Plant products as antimicrobial agents

Unveiling the Potent Antiviral and Antioxidant Activities of an Aqueous Extract from Caesalpinia mimosoides Lamk: Cheminformatics and Molecular Docking Approaches

Our group previously demonstrated that Caesalpinia mimosoides Lamk exhibits many profound biological properties, including anticancer, antibacterial, and antioxidant activities. However, its antiviral activity has not yet been investigated. Here, the aqueous extract of C. mimosoides was prepared from the aerial parts (leaves, stalks, and trunks) to see whether it exerts anti-influenza (H1N1) effects and to reduce the organic solvents consumed during extraction, making it a desirable approach for the large-scale production for medical uses. Our plant extract was quantified to contain 7 g of gallic acid (GA) per 100 g of a dry sample, as determined using HPLC analysis. It also exerts potent antioxidant activities comparable to those of authentic GA. According to untargeted metabolomics (UPLC-ESI(-)-QTOF-MS/MS) with the aid of cheminformatics tools (MetFrag (version 2.1), SIRIUS (version 5.8.3), CSI:FingerID (version 4.8), and CANOPUS), the major metabolite was best annotated as "gallic acid", phenolics (e.g., quinic acid, shikimic acid, and protocatechuic acid), sugar derivatives, and dicarboxylic acids were deduced from this plant species for the first time. The aqueous plant extract efficiently inhibited an influenza A (H1N1) virus infection of MDCK cells with an IC50 of 5.14 µg/mL. Of equal importance, hemolytic activity was absent for this plant extract, signifying its applicability as a safe antiviral agent. Molecular docking suggested that GA interacts with conserved residues (e.g., Arg152 and Asp151) located in the catalytic inner shell of the viral neuraminidase (NA), sharing the same pocket as those of anti-neuraminidase drugs, such as laninamivir and oseltamivir. Additionally, other metabolites were also found to potentially interact with the active site and the hydrophobic 430-cavity of the viral surface protein, suggesting a possibly synergistic effect of various phytochemicals. Therefore, the C. mimosoides aqueous extract may be a good candidate for coping with increasing influenza virus resistance to existing antivirals.

Possible Beneficial Effects of Hydrolyzable Tannins Deriving from Castanea sativa L. in Internal Medicine

Hydrolyzable tannins (HTs) deriving from chestnuts have demonstrated, through numerous studies, the ability to exert multiple beneficial effects, including antioxidant and antimicrobial effects, on the lipid metabolism and cancer cells. The latter effect is very fascinating, since different polyphenols deriving from chestnuts were able to synergistically induce the inhibition of cancerous cells through multiple pathways. Moreover, the main mechanisms by which tannins induce antioxidant functions include: the reduction in oxidative stress, the ability to scavenge free radicals, and the modulation of specific enzymes, such as superoxide dismutase. HTs have also been shown to exert significant antimicrobial activity by suppressing microbial growth. The actions on the lipid metabolism are several, among which is the inhibition of lipid accumulation. Thus, tannins seem to induce a cardioprotective effect. In fact, through various mechanisms, such as the relaxation of the vascular smooth muscle, HTs were proven to be efficient against arterial hypertension. Therefore, the great number of studies in this field prove the growing interest on the utilization of natural bioactive compounds, such as HTs deriving from natural sources or obtained by circular economy models, as potential nutraceuticals or adjuvants therapies.

Determining the In Vivo Efficacy of Plant-Based and Probiotic-Based Antibiotic Alternatives against Mixed Infection with Salmonella enterica and Escherichia coli in Domestic Chickens

Restrictions on the use of antimicrobial compounds have led to a surge of interest in alternative solutions, such as natural, plant-based compounds. In our study, we investigated the efficacy of three feed supplements containing different additives, namely, probiotics (Lactobacillus spp., "Test substance A"), turmeric (Curcuma longa L., "Test substance B"), and fenugreek (Trigonella foenum graecum, "Test substance C"). In the experiment, we tested 180 birds of the Bábolna Tetra-SL laying hybrid breed that were infected with Salmonella enteritidis strains. The birds were randomly divided into six groups: three groups treated with the different additives, a negative control group, a positive control group, and an antibiotic-treated group using enrofloxacin. We examined the maturation and the time course of shedding of Salmonella; at the end of rearing, pathological and histopathological examinations were performed. When Salmonella was isolated from the cloacal swab samples, the enrofloxacin-treated group had a high number of animals shedding Salmonella by day 9, which was like the group treated with test material C. The greatest reduction in Salmonella shedding was observed in the groups treated with test materials A and B. In terms of pathological parameters, villus length and crypt depth were significantly better in the group treated with test material C compared to the positive and negative controls, and when comparing the body weight of the tested animals, the group treated with test material B had a significantly larger absorption surface area compared to the positive control group. Overall, the supplement with test material C proved to be the most effective. In the future, it is worthwhile to investigate the combination of the tested active substances for their possible synergistic effects and to perform a dose-response study to select the optimal dosage.

The potential of gamma irradiation on antioxidant capacity and genomic alterations in Calendula officinalis

There are lines of evidence that ionizing radiations such as gamma rays can cause different biological effects on plants. Marigold (Calendula officinalis L.) is a member of the family Asteraceae. It possesses profound amounts of active ingredients. The aim of this study was to evaluate the changes imposed upon different dose levels of gamma radiation on some features of Calendula officinalis such as antioxidant activity, total phenolic compounds and flavonoid contents, antibacterial activity and genomic alterations. Calendula officinalis seeds were exposed to different doses of Gamma radiation (0, 10, 15, 20 and 25 GY). Total phenolics, flavonoids, antioxidant activity (measured by DPPH assay) using methanolic extracts of plants and antibacterial activity measured by the disc diffusion assay showed significant differences to the control samples. The samples treated with 10 GY gamma rays showed the highest total phenol and flavonoid contents. Antioxidant activity significantly differed between Gamma rays dose levels and it was the highest at 25 GY. Four bacterial strains including E. coli, Bacillus subtilis and Pseudomonas aeroginosa were used for the antibacterial assay. Extracts from plants treated with 25 GY gamma rays showed the highest antibacterial activity against the 4 bacterial strains. Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers were used to study the genetic variation. The polymorphism information content (PIC) for RAPD primers ranged from 3% to 13% and ranged from 6 to 13% for ISSR primers. Results indicated that ISSR markers were more efficient than RAPD markers, as they detected 25.57% polymorphic DNA bands compared to 21.31% polymorphism for RAPD markers.

Interactions of naturally occurring compounds with antimicrobials

Antibiotics are among the most often used medications in human healthcare and agriculture. Overusing these substances can lead to complications such as increasing antibiotic resistance in bacteria or a toxic effect when administering large amounts. To solve these problems, new solutions in antibacterial therapy are needed. The use of natural products in medicine has been known for centuries. Some of them have antibacterial activity, hence the idea to combine their activity with commercial antibiotics to reduce the latter's use. This review presents collected information on natural compounds (terpenes, alkaloids, flavonoids, tannins, sulfoxides, and mycotoxins), of which various drug interactions have been observed. Many of the indicated compounds show synergistic or additive interactions with antibiotics, which suggests their potential for use in antibacterial therapy, reducing the toxicity of the antibiotics used and the risk of further development of bacterial resistance. Unfortunately, there are also compounds which interact antagonistically, potentially hindering the therapy of bacterial infection. Depending on its mechanism of action, each compound can behave differently in combination with different antibiotics and when acting against various bacterial strains.

Cellulose Nanocrystal-Based Emulsion of Thyme Essential Oil: Preparation and Characterisation as Sustainable Crop Protection Tool

Essential oil-based pesticides, which contain antimicrobial and antioxidant molecules, have potential for use in sustainable agriculture. However, these compounds have limitations such as volatility, poor water solubility, and phytotoxicity. Nanoencapsulation, through processes like micro- and nanoemulsions, can enhance the stability and bioactivity of essential oils. In this study, thyme essential oil from supercritical carbon dioxide extraction was selected as a sustainable antimicrobial tool and nanoencapsulated in an oil-in-water emulsion system. The investigated protocol provided high-speed homogenisation in the presence of cellulose nanocrystals as stabilisers and calcium chloride as an ionic crosslinking agent. Thyme essential oil was characterised via GC-MS and UV-vis analysis, indicating rich content in phenols. The cellulose nanocrystal/essential oil ratio and calcium chloride concentration were varied to tune the nanoemulsions' physical-chemical stability, which was investigated via UV-vis, direct observation, dynamic light scattering, and Turbiscan analysis. Transmission electron microscopy confirmed the nanosized droplet formation. The nanoemulsion resulting from the addition of crosslinked nanocrystals was very stable over time at room temperature. It was evaluated for the first time on Pseudomonas savastanoi pv. savastanoi, the causal agent of olive knot disease. In vitro tests showed a synergistic effect of the formulation components, and in vivo tests on olive seedlings demonstrated reduced bacterial colonies without any phytotoxic effect. These findings suggest that crosslinked cellulose nanocrystal emulsions can enhance the stability and bioactivity of thyme essential oil, providing a new tool for crop protection.

Phytochemical Composition, Antioxidant, Antimicrobial, Antibiofilm, and Antiquorum Sensing Potential of Methanol Extract and Essential Oil from Acanthus polystachyus Delile (Acanthaceae)

The evolution of microbes in response to conventional antimicrobials leads to antimicrobial resistance (AMR) and multidrug resistance (MDR), and it is a global threat to public health. Natural products are possible solutions to this massive challenge. In this study, the potential of Acanthus polystachyus extracts was investigated for phytochemical composition and biological properties as antimicrobials. Gas chromatography-mass spectra (GC-MS) analysis of methanol extract (ME) and essential oil (EO) detected 79 and 20 compounds, respectively. The major compounds identified in ME and their abundance were β-sitosterol acetate (16.06%), cholest-5-en-3-yl (9Z)-9-octadecenoate (9.54%), 1-dodecanol (7.57%), (S)-(E)-(-)-4-acetoxy-1-phenyl-2-dodecen-1-one (6.03%), neophytadiene (5.7%), (E)-2-nonadecene (3.9%), hexanol-4-D2 (2.92%), and decane (2.4%). Most compounds have known bioactive functions. In EO, the major compounds were stearyl alcohol (25.38%); cis-9-tetradecenoic acid, isobutyl ester (22.95%); butyl 9-tetradecenoate (10.62%); 11,13-dimethyl-12-tetradecen-1-ol acetate (10.14%); ginsenol (3.48%); and diisooctyl phthalate (2.54%). All compounds are known to be bioactive. The antioxidant activity of ME and EO ranged from 48.3 to 84.2% radical scavenging activity (RSA) and 45.6 to 82% RSA, respectively, with dose dependency. The disc diffusion assay for the antimicrobial activity of ME revealed high inhibition against Acenetobacter baumannii (130.2%), Pseudomonas aeruginosa (100.3%), and Staphylococcus aureus (87.7%). The MIC, MBC/MFC, and MBIC values for ME were 0.5-1.0, 2-4, and 0.5-1.0 mg/mL and for EO were 0.31-0.62, 1.25-2.5, and 0.31-0.62 μL/mL, respectively, indicating inhibition potential as well as inhibition of biofilm formation. The tolerance test values indicated bactericidal activity against most strains and bacteriostatic/fungistatic activity against A. baumannii, E. faecalis, and C. albicans. The antiquorum sensing activity of ME achieved by pyocyanin inhibition assay on P. aeruginosa showed a 51.6% inhibition at 500 μg/mL. These results suggest that ME and EO derived from A. polystachyus leaves are potent, valuable, cost-effective antioxidants and antimicrobials. Both extracts may effectively combat pathogenic and resistant microbes.

Antibacterial stigmastane-type steroids and other constituents from the leaves of Vernonia glabra (Steetz) Vatke (Asteraceae)

Two new stigmastane steroids (1 and 2) were isolated from the methanol extract of the leaves of Vernonia glabra, together with seventeen known compounds (3-19) including one fatty acid, four triterpenoids, four steroids, one trinitropropanoyl glucoside, and seven flavonoids. The structures of compounds 1 and 2 were assigned based on their IR, NMR and MS data, and by comparison with literature values. The MeOH extract, its fractions and isolated compounds were subjected to in vitro antibacterial assay against two Gram-positive (Staphylococcus aureus ATCC25923 and Streptococcus pneumoniae ATCC49619) and two Gram-negative (Escherichia coli ATCC8739 and Klebsiella pneumoniae ATCC10031) bacteria, using broth microdilution method. The extract and fractions exhibited (16 ≤ MIC ≤ 512 μg/mL) antibacterial activities. The isolated and tested compounds were also active (16 ≤ MIC ≤ 128 μg/mL) against the four pathogenic bacteria, with compound 2 being the most active and E. coli, the most sensitive microorganism.

Evaluation of the Antioxidant, Antimicrobial, and Anti-Biofilm Effects of the Stem Bark, Leaf, and Seed Extracts from Hymenaea courbaril and Characterization by UPLC-ESI-QTOF-MS/MS Analysis

Currently, biofilm-forming bacteria are difficult to treat by conventional antibiotic therapy and are, thus, becoming a clinical and epidemiological problem worldwide. Medicinal plants have been identified as novel alternative treatments due to their therapeutic and antimicrobial effects. In this context, the present study aimed to determine the total phenolic content, antioxidant capacity, and antimicrobial and anti-biofilm potential of nine extracts of Hymenaea courbaril (Fabaceae), popularly known as Jatobá. Furthermore, extracts that exhibited biofilm inhibitory activity against S. aureus (ATCC 25923) were selected for UPLC-HRMS/MS chemical analysis. Our results showed a high total phenolic content, mainly in the stem bark extract, and that the plant is rich in compounds with antioxidant activity. In the anti-biofilm analysis, leaf extracts stood out in comparison with chloramphenicol, with inhibition percentages of 78.29% and 78.85%, respectively. Through chemical analysis by UPLC-HRMS/MS, chrysoeriol-7-O-neohesperidoside, isorhamnetin-3-O-glucoside, and 3,7-di-O-methylquercetin were annotated for the first time in the leaves of H. courbaril. Therefore, these results showed the potential use of H. courbaril as an antioxidant and point to its use in antimicrobial therapy with an anti-biofilm effect.

Bakuchiol, a natural constituent and its pharmacological benefits

Background and aims

Natural compounds extracted from medicinal plants have recently gained attention in therapeutics as they are considered to have lower Toxicity and higher tolerability relative to chemically synthesized compounds. Bakuchiol from Psoralea corylifolia L. is one such compound; it is a type of meroterpene derived from the leaves and seeds of Psoralea corylifolia plants. Natural sources of bakuchiol have been used in traditional Chinese and Indian medicine for centuries due to its preventive benefits against tumors and inflammation. It plays a strong potential role as an antioxidant with impressive abilities to remove Reactive Oxygen Species (ROS). This review has focused on bakuchiol's extraction, therapeutic applications, and pharmacological benefits.

Methods

A search strategy has been followed to retrieve the relevant newly published literature on the pharmacological benefits of bakuchiol. After an extensive study of the retrieved articles and maintaining the inclusion and exclusion criteria, 110 articles were finally selected for this review.

Results

Strong support of primary research on the protective effects via antitumorigenic, anti-inflammatory, antioxidative, antimicrobial, and antiviral activities are delineated.

Conclusions

From ancient to modern life, medicinal plants have always been drawing the attention of human beings to alleviate ailments for a healthy and balanced lifestyle. This review is a comprehensive approach to highlighting bona fide essential pharmacological benefits and mechanisms underlying their therapeutic applications.

Phytochemical composition, cytotoxicity, antioxidant and antimicrobial responses of Lavandula dentata L. grown under different levels of heavy metals stress condition

In order to know if the heavy metals stress condition is boon or bane for the plants growth, Lavandula dentata species was planted in pots under different levels of heavy metals stress condition and the phytochemical composition, cytotoxicity, antioxidant and antimicrobial responses of their leaf ethanolic extracts toward this stress condition were investigated compared to the control samples. Our findings showed significant differences in heavy metals bioaccumulation, photosynthetic pigments and total phenolic/flavonoids contents among L. dentata leafs ethanolic extracts, grown under different levels of heavy metals stress condition. The L. dentata leafs extracts, grown under Zn and Cu stress condition, showed the highest antioxidant and antimicrobial activities than those grown under Cd and Pb stress condition. Comparatively, the L. dentata leafs extracts, grown under Zn stress condition, showed higher antioxidant activity, and those, grown under Cu stress condition, showed higher antimicrobial activity. The highest cytotoxicity was showed by L. dentata leaf extracts, grown under Cd and Pb stress condition, which lead to conclude that these extracts could be served as a novel scaffold in search for new drugs against cancer. In conclusion, the highlighted variability reflects the high impact of heavy metals stress condition on phytochemical composition and consequently on the biological activities of medicinal plants. Such impact led to conclude that we should select medicinal plants extracts to be investigated carefully depending on this stress condition, in order to isolate the bioactive components or to have the best quality of extracts in terms of biological activities.

Study of chemical constituents, antioxidants and antimicrobial activities of Tamarindus indica L. seed

The fruits of Tamarindus indica L. are consumed worldwide, with various parts of the plant being used for medicinal purposes. The residues (pericarp and seeds) generated during cellulose processing are of significant value as they contain bioactive compounds with diverse biological activities. The objective of this study was to evaluate the chemical constituents of the ethyl acetate fraction as possible substitutes for synthetic compounds with biological properties using ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS/MS) analysis and the evaluation of the antioxidant activity (ferric reducing antioxidant power [FRAP], 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid [ABTS], and 1-diphenyl-2-picrylhydrazyl [DPPH]), total phenolic compounds (TPC), and antimicrobial activity of the hydroalcoholic extract and tamarind seed fractions were also performed. The chemical investigation of the acetate fraction using UHPLC-HRMS/MS resulted in the putative identification of 14 compounds, including flavonoids, (+)-catechin/(-)-epicatechin, procyanidin B2, procyanidin C2, isoquercetin, quercetin, luteolin, rutin, taxifolin, eriodictyol, kaempferide, hydroxybenzoic acid, protocathecuic acid, and protocathecuic acid methyl and ethyl esters derivatives. The crude hydroalcoholic extract exhibited the best results in terms of TPC: 883.87 gallic acid equivalent (GAE; mg/g) and antioxidant activity: FRAP: 183.29 GAE (mg/g), ABTS: 39.67%, and DPPH: 91.08%. The extract exhibited excellent antibacterial activity against gram-positive bacteria, specifically Staphylococcus aureus minimum inhibitory concentration (MIC)/minimum bactericidal concentration (MBC; 62.5/125 g/mL) and Bacillus cereus MIC/MBC (125/250 g/mL), and gram-negative bacteria, specifically Aeromonas hydrophila MIC/MBC (125/250 µg/mL) and Pseudomonas aeruginosa MIC/MBC (250/500 g/mL). Morphological damage to cells was observed using flow cytometry and scanning electron microscopy. Tamarind seeds contain unique bioactive compounds that should be explored for their use as novel food preservatives. PRACTICAL APPLICATION: Original data were obtained regarding the Tamarindus indica L. seed extract and the ethyl acetate and hexane fractions. This research aimed to investigate the potential of these for food preservation and as alternatives to additives and synthetic compounds added to cattle feed. This paper reports novel findings regarding the chemical composition of the extract and its antioxidant activity, along with its antimicrobial activity against bacteria (gram-positive: Staphylococcus aureus, Bacillus cereus, and gram-negative: Salmonella enterica serovar Enteritidis, Escherichia coli, Pseudomonas aeruginosa, and Aeromonas hydrophila) and yeasts (Candida albicans and Saccharomyces cerevisiae).

Bioassay-Guided Assessment of Antioxidative, Anti-Inflammatory and Antimicrobial Activities of Extracts from Medicinal Plants via High-Performance Thin-Layer Chromatography

Natural products and their analogues have contributed significantly to treatment options, especially for anti-inflammatory and infectious diseases. Thus, the primary objective of this work was to compare the bioactivity profiles of selected medicinal plants that are historically used in folk medicine to treat inflammation and infections in the body. Chemical HPTLC fingerprinting was used to assess antioxidant, phenolic and flavonoid content, while bioassay-guided HPTLC was used to detect compounds with the highest antibacterial and anti-inflammatory activities. The results of this study showed that green tea leaf, walnut leaf, St. John's wort herb, wild thyme herb, European goldenrod herb, chamomile flower, and immortelle flower extracts were strong radical scavengers. Green tea and nettle extracts were the most active extracts against E. coli, while calendula flower extract showed significant potency against S. aureus. Furthermore, green tea, greater celandine, and fumitory extracts exhibited pronounced potential in suppressing COX-1 activity. The bioactive compounds from the green tea extract, as the most bioactive, were isolated by preparative thin-layer chromatography and characterized with their FTIR spectra. Although earlier studies have related green tea's anti-inflammatory properties to the presence of catechins, particularly epigallocatechin-3-gallate, the FTIR spectrum of the compound from the most intense bioactive zone showed the strongest anti-inflammatory activity can be attributed to amino acids and heterocyclic compounds. As expected, antibacterial activity in extracts was related to fatty acids and monoglycerides.

Artemisia brevifolia Wall. Ex DC Enhances Cefixime Susceptibility by Reforming Antimicrobial Resistance

(1) Background: A possible solution to antimicrobial resistance (AMR) is synergism with plants like Artemisia brevifolia Wall. ex DC. (2) Methods: Phytochemical quantification of extracts (n-hexane (NH), ethyl acetate (EA), methanol (M), and aqueous (Aq)) was performed using RP-HPLC and chromogenic assays. Extracts were screened against resistant clinical isolates via disc diffusion, broth dilution, the checkerboard method, time-kill, and protein quantification assays. (3) Results: M extract had the maximum phenolic (15.98 ± 0.1 μg GAE/mgE) and flavonoid contents (9.93 ± 0.5 μg QE/mgE). RP-HPLC displayed the maximum polyphenols in the M extract. Secondary metabolite determination showed M extract to have the highest glycosides, alkaloids, and tannins. Preliminary resistance profiling indicated that selected isolates were resistant to cefixime (MIC 20-40 µg/mL). Extracts showed moderate antibacterial activity (MIC 60-100 µg/mL). The checkerboard method revealed a total synergy between EA extract and cefixime with 10-fold reductions in cefixime dose against resistant P. aeruginosa and MRSA. Moreover, A. brevifolia extracts potentiated the antibacterial effect of cefixime after 6 and 9 h. The synergistic combination was non- to slightly hemolytic and could inhibit bacterial protein in addition to cefixime disrupting the cell wall, thus making it difficult for bacteria to survive. (4) Conclusion: A. brevifolia in combination with cefixime has the potential to inhibit AMR.

Heteroleptic Silver(I) and Gold(I) N-Heterocyclic Carbene Complexes: Structural Characterization, Computational Analysis, Tyrosinase Inhibitory, and Biological Effects

Derivatization of (NHC)M-Cl (M = Ag, Au) with selected sulfur donors from the family of dialkyldithiophosphates and bis(2-mercapto-1-methylimidazolyl)borate ligands gave a series of heteroleptic mononuclear complexes. In single-crystal X-ray diffraction analysis, Ag(I) complexes adopted a trigonal planar geometry, while Au(I) complexes are near-linear. TD-DFT and hole-electron analyses of the selected complexes gave insight into the electronic features of the metal complexes. In vitro cellular tests were conducted on the human cancerous breast cell line MCF-7 using 2 and 8. The antibacterial activities of complexes 1, 2, 3, 7, 8, and IPr-Ag-Cl were also screened against Gram-positive (Staphylococcus aureus PTCC 1112) and Gram-negative (Escherichia coli PTCC 1330) bacteria. Antityrosinase and hemolytic effects of the selected compounds were also determined.

Mineral composition, the profile of phenolic compounds, organic acids, sugar and in vitro antioxidant capacity, and antimicrobial activity of organic extracts of Juniperus drupacea fruits

Juniperus drupacea fruit is widely used in traditional and complementary medicine in Turkey for the treatment of different diseases in various forms such as molasses and tar. This study was carried out to evaluate the phenolic compounds, organic acid, sugar, and macro- and micromineral distributions of methanol and water extracts of J. drupace fruit, as well as their antioxidant and antimicrobial potential. For this purpose, total phenolic content by spectrophotometer, phenolics, organic acids, and sugars distributions by HPLC in extracts of J. drupacea fruits, and macro- and micromineral element content by ICP-AES in fruit were determined. 2,2-diphenyl-l-picrylhydrazyl assay (DPPH assay) was used to evaluate in vitro antioxidant activity in extracts. The antimicrobial potential of J. drupacea fruit methanol extract against some gram-positive and gram-negative pathogenic bacteria was evaluated using disk diffusion and minimum inhibitory concentration (MIC) methods. The potassium macroelement and the iron microelement were found at high content in J. drupacea fruit. The total phenolic content in the methanol extracts was higher than the water extracts. Among the individual phenolic compounds, catechin, a flavonoid that was the highest in both extractions, was determined as 300.49 μg/g in methanol extract and 314.88 μg/g in water extract. DPPH scavenging activity was higher in methanol extracts. While the methanol extract of J. drupacea had no-inhibitory effect on the gram-negative bacteria tested, it exhibited a strong inhibition on the gram-positive bacteria Listeria innocua, Listeria monocytogenes, Staphylococcus carnosus, and Enterococcus faecalis.

Comparative analysis of antimicrobial compounds from endophytic Buergenerula spartinae from orchid

A rare fungal endophyte, identified as Buergenerula spartinae (C28), was isolated from the roots of Cymbidium orchids and was characterised and evaluated for its antimicrobial activities. Bio-guided fractionation revealed 4 fractions from B. spartinae (C28) having antibacterial activities against at least one bacterial pathogen tested (Bacillus cereus and Staphylococcus aureus). However, inhibitory activities were absent against pathogenic fungi (Ganoderma boninense, Pythium ultimum and Fusarium solani). Fraction 2 and fraction 4 of B. spartinae (C28) exhibited potent antibacterial activities against S. aureus (MIC: 0.078 mg/mL) and B. cereus (MIC: 0.313 mg/mL), respectively. LCMS analysis revealed the presence of antibacterial agents and antibiotics in fraction 2 (benoxinate, pyropheophorbide A, (-)-ormosanine and N-undecylbenzenesulfonic acid) and fraction 4 (kaempferol 3-p-coumarate, 6-methoxy naphthalene acetic acid, levofuraltadone, hinokitiol glucoside, 3-α(S)-strictosidine, pyropheophorbide A, 5'-hydroxystreptomycin, kanzonol N and 3-butylidene-7-hydroxyphthalide), which may be responsible for the antibacterial activities observed. Most of the bioactive compounds profiled from the antibacterial fractions were discovered for the first time from endophytic isolates (i.e. from B. spartinae (C28)). Buergenerula spartinae (C28) from Cymbidium sp. is therefore, an untapped resource of bioactive compounds for potential applications in healthcare and commercial industries.

Evolution of five environmentally responsive gene families in a pine-feeding sawfly, Neodiprion lecontei (Hymenoptera: Diprionidae)

A central goal in evolutionary biology is to determine the predictability of adaptive genetic changes. Despite many documented cases of convergent evolution at individual loci, little is known about the repeatability of gene family expansions and contractions. To address this void, we examined gene family evolution in the redheaded pine sawfly Neodiprion lecontei, a noneusocial hymenopteran and exemplar of a pine-specialized lineage evolved from angiosperm-feeding ancestors. After assembling and annotating a draft genome, we manually annotated multiple gene families with chemosensory, detoxification, or immunity functions before characterizing their genomic distributions and molecular evolution. We find evidence of recent expansions of bitter gustatory receptor, clan 3 cytochrome P450, olfactory receptor, and antimicrobial peptide subfamilies, with strong evidence of positive selection among paralogs in a clade of gustatory receptors possibly involved in the detection of bitter compounds. In contrast, these gene families had little evidence of recent contraction via pseudogenization. Overall, our results are consistent with the hypothesis that in response to novel selection pressures, gene families that mediate ecological interactions may expand and contract predictably. Testing this hypothesis will require the comparative analysis of high-quality annotation data from phylogenetically and ecologically diverse insect species and functionally diverse gene families. To this end, increasing sampling in under-sampled hymenopteran lineages and environmentally responsive gene families and standardizing manual annotation methods should be prioritized.

Chemical characterization of Callingcard Vine (Entada polystachya (L.) DC. var. polystachya) aqueous seed extract and evaluation of its cytotoxic, genotoxic and mutagenic properties

Callingcard Vine (Entada polystachya (L.) DC. var. polystachya - Fabaceae) is a common plant in coastal thickets from western Mexico through Central America to Colombia and Brazil, especially in Amazon biome. It has been popularly used as a urinary burning reliever and diuretic. However, the plant chemical constituents are poorly understood and Entada spp. genotoxic potential have not been previously investigated. In the present study we determined the chemical composition of the aqueous E. polystachya crude seed extract (EPCSE) and evaluated the cytotoxic, genotoxic and mutagenic properties of EPCSE in Salmonella typhimurium and Chinese hamster fibroblast (V79) cells. Cytotoxic activity was also evaluated in tumor cell lines (HT29, MCF7 and U87) and non-malignant cells (MRC5). The chemical analysis by High Resolution Mass Spectrometry (HRMS) of EPCSE indicated the presence of saponin and chalcone. The results of the MTT and clonal survival assays suggest that EPCSE is cytotoxic to V79 cells. Survival analysis showed higher IC50 in non-tumor compared with tumor cell lines. EPCSE showed induction of DNA strand breaks as revealed by the alkaline comet assay and micronucleus test. Using the modified comet assay, it was possible to detect the induction of oxidative DNA base damage by EPCSE in V79 cells. Consistently, the extract induced increase lipid peroxidation (TBARS), superoxide dismutase (SOD) and catalase (CAT) activities in V79 cells. In addition, EPCSE induced mutations in S. typhimurium TA98 and TA100 strains, confirming a mutagenic potential. Taken together, our results suggest that EPCSE is cytotoxic and genotoxic to V79 cells and mutagenic to S. typhimurium. These properties can be related to the pro-oxidant ability of the extract and induction of DNA lesions. Additionally, EPCSE could inhibit the growth of tumor cells, especially human colorectal adenocarcinoma (HT29) cell line, and can constitute a possible source of antitumor natural agents.

Evolving biofilm inhibition and eradication in clinical settings through plant-based antibiofilm agents

BACKGROUND

After almost 100 years since evidence of biofilm mode of growth and decades of intensive investigation about their formation, regulatory pathways and mechanisms of antimicrobial tolerance, nowadays there are still no therapeutic solutions to eradicate bacterial biofilms and their biomedical related issues.

PURPOSE

This review intends to provide a comprehensive summary of the recent and most relevant published studies on plant-based products, or their isolated compounds with antibiofilm activity mechanisms of action or identified molecular targets against bacterial biofilms. The objective is to offer a new perspective of most recent data for clinical researchers aiming to prevent or eliminate biofilm-associated infections caused by bacterial pathogens.

METHODS

The search was performed considering original research articles published on PubMed, Web of Science and Scopus from 2015 to April 2023, using keywords such as "antibiofilm", "antivirulence", "phytochemicals" and "plant extracts".

RESULTS

Over 180 articles were considered for this review with a focus on the priority human pathogens listed by World Health Organization, including Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli. Inhibition and detachment or dismantling of biofilms formed by these pathogens were found using plant-based extract/products or derivative compounds. Although combination of plant-based products and antibiotics were recorded and discussed, this topic is currently poorly explored and only for a reduced number of bacterial species.

CONCLUSIONS

This review clearly demonstrates that plant-based products or derivative compounds may be a promising therapeutic strategy to eliminate bacterial biofilms and their associated infections. After thoroughly reviewing the vast amount of research carried out over years, it was concluded that plant-based products are mostly able to prevent biofilm formation through inhibition of quorum sensing signals, but also to disrupt mature biofilms developed by multidrug resistant bacteria targeting the biofilm extracellular polymeric substance. Flavonoids and phenolic compounds seemed the most effective against bacterial biofilms.

Furanonaphthoquinones, Diterpenes, and Flavonoids from Sweet Marjoram and Investigation of Antimicrobial, Bacterial Efflux, and Biofilm Formation Inhibitory Activities

The chloroform extract of Origanum majorana exhibited high antibacterial and antifungal activities against 12 bacterial and 4 fungal strains; therefore, it was subjected to bioassay-guided isolation to afford six compounds (1-6). The structures were determined via one- and two-dimensional nuclear magnetic spectroscopy and high-resolution electrospray ionization mass spectrometry experiments. The compounds were identified as furanonaphthoquinones [majoranaquinone (1), 2,3-dimethylnaphtho[2,3-b]furan-4,9-dione (2)], diterpenes [19-hydroxyabieta-8,11,13-trien-7-one (3), 13,14-seco-13-oxo-19-hydroxyabieta-8-en-14-al (4)], and flavonoids [sterubin (5) and majoranin (6)]. Compounds 1 and 2 were first obtained from a natural source and compounds 3 and 4 were previously undescribed. Majoranaquinone (1) exhibited a high antibacterial effect against 4 Staphylococcus, 1 Moraxella, and 1 Enterococcus strains (MIC values between 7.8 μM and 1 mM). In the efflux pump inhibition assay, majoranaquinone (1) showed substantial activity in Escherichia coli ATCC 25922 strain. Furthermore, 1 was found to be an effective biofilm formation inhibitor on E. coli ATCC 25922 and E. coli K-12 AG100 bacteria. Our findings proved that bioactivities of majoranaquinone (1) significantly exceed those of the essential oil constituents; therefore, it should also be considered when assessing the antimicrobial effects of O. majorana.

Molecular Docking Study of the C-10 Massoia Lactone Compound as an Antimicrobial and Antibiofilm Agent against Candida tropicalis

Antimicrobial resistance is now considered a global health problem because it reduces the effectiveness of antimicrobial drugs. According to the World Health Organization (WHO), the highest mortality rate is associated with infections caused by multidrug-resistant microorganisms, with approximately 700,000 deaths worldwide each year. The aim of this study was to determine the potential of C-10 massoia lactone to inhibit the growth of fungi and C. tropicalis biofilm, and molecular docking studies were performed to determine the nature of the inhibition. The study was conducted using the microdilution method for antifungal and antibiofilm testing and designed with a molecular docking approach. Furthermore, an analysis using the scanning electron microscope (SEM) was performed to evaluate the mechanism of effect. The results obtained showed that C-10 massoia lactone can inhibit the growth of fungi by 84.21% w/v. Meanwhile, the growth of C. tropicalis biofilm in the intermediate phase was 80.23% w/v and in the mature phase was 74.23% w/v. SEM results showed that C-10 massoia lactone damaged the EPS matrix of C. tropicalis so that hyphal formation was hindered due to damage to fungal cells, resulting in a decrease in attachment, density, and lysis of C. tropicalis fungal cells. Based on molecular docking tests, C-10 massoia lactone was able to inhibit biofilm formation without affecting microbial growth, while docking C-10 massoia lactone showed a significant binding and has the potential as an antifungal agent. In conclusion, the C-10 massoia lactone compound has the potential as an antibiofilm against C. tropicalis, so it can become a new antibiofilm agent.

Antimicrobial Activity of Frankincense (Boswellia sacra) Oil and Smoke against Pathogenic and Airborne Microbes

As they continuously evolve, plants will remain a renewable source for antimicrobial compounds. Omani frankincense is produced by B. sacra trees and is graded into Hojari, Nejdi, Shazri or Sha'bi. Air can be a source for pathogenic or food spoilage microbes; thus, inactivating airborne microbes is necessary in environments such as food and animal production areas. This study investigated the antimicrobial activity and the chemistry of steam-distilled oils of Hojari and Sha'bi grades. It also analyzed the antimicrobial activity of frankincense smoke and the size of its solid particles. Chemical analysis was performed using gas chromatography mass spectrometry (GC-MS). The antimicrobial activity of the oils against Staphylococcus aureus (NCTC 6571), Bacillus spp., Escherichia coli (NCTC 10418), Pseudomonas aeruginosa (NCTC 10662), Saccharomyces cerevisiae, Candida albicans, Aspergillus flavus, Aspergillus ochraceus, Aspergillus niger, Penicillium citrinum, Alternaria alternata and Fusarium solani was determined using well diffusion and micro-well dilution methods. A microscopic technique was used to determine the size of frankincense smoke solid particles. Microbes were exposed to frankincense smoke to test their susceptibility to the smoke. Hojari and Sha'bi oils were similar in composition and contained monoterpenes and sesquiterpenes. The Hojari and the Sha'bi oils possessed broad spectrum antimicrobial activity. The largest growth inhibition zones were obtained with S. cerevisiae and F. solani. An MIC of 1.56% (v/v) was found with E. coli, S. cerevisiae and F. solani. Frankincense smoke contained fine irregular solid particles with a diameter range of 0.8-2287.4 µm, and thus may pose a health risk to susceptible individuals. The smoke had potent antimicrobial activity against S. aureus, E. coli, and airborne bacteria, yeast and mold, with a maximum inhibition of 100%. It was concluded that Hojari and Sha'bi frankincense oils and smoke had significant antimicrobial activity that can be exploited in controlling human, animal and plant pathogenic microbes.

Control of the Growth of Listeria monocytogenes in Cooked Ham through Combinations of Natural Ingredients

In the ready-to-eat food industry, Listeria control is mandatory to ensure the food safety of the products since its presence could cause a disease called listeriosis. The objective of the present study was to carry out a challenge test to verify the efficiency of different combinations of natural antimicrobial ingredients against Listeria monocytogenes to be used in ready-to-eat foods. Six different formulations of cooked ham were prepared: a control formulation and five different formulations. An initial inoculation of 2 log cycles was used in the different products, and the growth of Listeria was monitored at different temperatures and times (4 °C for 17 w and 7 °C for 12 w). Control samples showed a progressive growth, reaching 5-6 log after 3 or 4 weeks. The rest of the samples showed constant counts of Listeria during the entire study. Only samples containing 100 ppm nitrite + 250 PPM ascorbic acid + 0.7% PRS-DV-5 did not control the growth of Listeria at 7 °C after 7 w of storage. The results obtained allowed us to classify the cooked ham prepared using natural ingredient combinations as a "Ready-to-eat food unable to support the growth of L. monocytogenes other than those intended for infants and for special medical purposes".

Evaluation of Antimicrobial Activity of Kitaibelia vitifolia Extract against Proven Antibiotic-Susceptible and Multidrug-Resistant (MDR) Strains of Bacteria of Clinical Origin

The goal of the present research was to screen the antimicrobial activity of an ethanolic extract of Kitaibelia vitifolia against 30 multidrug-resistant (MDR) bacterial strains isolated from healthcare-associated infections. Minimum inhibitory concentrations (MICs) of the samples against the tested bacteria were determined using the microdilution method. MDR bacterial strains were characterized using standard biochemical tests and the commercial identification systems API 20 NE and API 20 E as: Klebsiella spp. (18 isolates-I); methicillin-resistant Staphylococcus aureus (MRSA)-3; Acinetobacter spp.-3; Pseudomonas aeruginosa-5; vancomycin-resistant Enterococcus (VRE)-1. The sensitivity of isolated bacterial strains was determined using the disc diffusion method against 25 commonly used antibiotics. The highest level of sensitivity to K. vitifolia extract was confirmed in 88.89% of Klebsiella spp. isolates, E. coli ATCC 25922, two strains of MRSA (1726, 1063), Acinetobacter spp. strain 1578, and VRE strain 30, like Enterococcus faecalis ATCC 29212 (MIC =< 2.44 μg/mL). The lowest sensitivity was exhibited by 75.00% of Acinetobacter spp. (strains 1577 and 6401), where the highest values for MICs were noted (1250 μg/mL). The results indicate that the extract of K. vitifolia could be a possible source for creating new, efficient, and effective natural medicines for combat against MDR strains of bacteria.

In Vivo, In Vitro and In Silico Study of Cucurbita moschata Flower Extract: A Promising Source of Natural Analgesic, Anti-Inflammatory, and Antibacterial Agents

For thousands of years, medicinal plants have played a pivotal role in maintaining human health and improving the quality of human life. This study was designed to analyze the analgesic, anti-inflammatory, and antibacterial potentials of a hydro-methanolic extract of Cucurbita moschata flowers, along with qualitative and quantitative phytochemical screening. The anti-inflammatory effect was tested using the in vitro membrane stabilizing method for human red blood cells (HRBC), the analgesic effect was tested using the in vivo acetic acid-induced writing method, and the antibacterial effect was tested using the disc diffusion method. In silico ADME/T and molecular docking studies were performed to assess the potential of the stated phytochemicals against Cyclooxygenase-II enzyme. Phytochemical screening confirmed the presence of flavonoids, alkaloids, glycosides, tannins, and carbohydrates. The flower extract demonstrated the maximum protection of human red blood cells at 1000 µg/mL, with a 65.73% reduction in hemolysis in a hypotonic solution. The extract also showed significant (p < 0.05) and dose-dependent analgesic effects at oral doses of 200 and 400 mg/kg on the tested animals. Furthermore, the flower extract exhibited potent antibacterial activity due to the disc diffusion method, which was compared with standard ciprofloxacin. In silico testing revealed that 42 phytochemicals exhibited notable pharmacokinetic properties and passed drug likeness screening tests. Among the six best-selected compounds, 3,4-dihydro-2H-pyran-2-yl)methanamine showed the highest binding affinity (-10.1) with significant non-bonding interactions with the target enzyme. In conclusion, the hydro-methanolic extract of Cucurbita moschata was found to be rich in various phytochemicals that may be associated with therapeutic potential, and this study supports the traditional use of Cucurbita moschata flowers in the management of inflammation and painful conditions.

Antimicrobial Peptides: The Production of Novel Peptide-Based Therapeutics in Plant Systems

The increased prevalence of antibiotic resistance is alarming and has a significant impact on the economies of emerging and underdeveloped nations. The redundancy of antibiotic discovery platforms (ADPs) and injudicious use of conventional antibiotics has severely impacted millions, across the globe. Potent antimicrobials from biological sources have been extensively explored as a ray of hope to counter the growing menace of antibiotic resistance in the population. Antimicrobial peptides (AMPs) are gaining momentum as powerful antimicrobial therapies to combat drug-resistant bacterial strains. The tremendous therapeutic potential of natural and synthesized AMPs as novel and potent antimicrobials is highlighted by their unique mode of action, as exemplified by multiple research initiatives. Recent advances and developments in antimicrobial discovery and research have increased our understanding of the structure, characteristics, and function of AMPs; nevertheless, knowledge gaps still need to be addressed before these therapeutic options can be fully exploited. This thematic article provides a comprehensive insight into the potential of AMPs as potent arsenals to counter drug-resistant pathogens, a historical overview and recent advances, and their efficient production in plants, defining novel upcoming trends in drug discovery and research. The advances in synthetic biology and plant-based expression systems for AMP production have defined new paradigms in the efficient production of potent antimicrobials in plant systems, a prospective approach to countering drug-resistant pathogens.

A Comprehensive Mini-Review on Lignin-Based Nanomaterials for Food Applications: Systemic Advancement and Future Trends

The shift to an environmentally friendly material economy requires renewable resource exploration. This shift may depend on lignin valorization. Lignin is an aromatic polymer that makes up one-third of total lingo-cellulosic biomass and is separated into large amounts for biofuel and paper manufacture. This renewable polymer is readily available at a very low cost as nearly all the lignin that is produced each year (90–100 million tons) is simply burned as a low-value fuel. Lignin offers potential qualities for many applications, and yet it is underutilized. This Perspective highlights lignin-based material prospects and problems in food packaging, antimicrobial, and agricultural applications. The first half will discuss the present and future studies on exploiting lignin as an addition to improve food packaging’s mechanical, gas, UV, bioactive molecules, polyphenols, and antioxidant qualities. Second, lignin’s antibacterial activity against bacteria, fungi, and viruses will be discussed. In conclusion, lignin agriculture will be discussed in the food industries.

A Comprehensive Mini-Review on Lignin-Based Nanomaterials for Food Applications: Systemic Advancement and Future Trends

The shift to an environmentally friendly material economy requires renewable resource exploration. This shift may depend on lignin valorization. Lignin is an aromatic polymer that makes up one-third of total lingo-cellulosic biomass and is separated into large amounts for biofuel and paper manufacture. This renewable polymer is readily available at a very low cost as nearly all the lignin that is produced each year (90-100 million tons) is simply burned as a low-value fuel. Lignin offers potential qualities for many applications, and yet it is underutilized. This Perspective highlights lignin-based material prospects and problems in food packaging, antimicrobial, and agricultural applications. The first half will discuss the present and future studies on exploiting lignin as an addition to improve food packaging's mechanical, gas, UV, bioactive molecules, polyphenols, and antioxidant qualities. Second, lignin's antibacterial activity against bacteria, fungi, and viruses will be discussed. In conclusion, lignin agriculture will be discussed in the food industries.

Natural phenolic compounds as biofilm inhibitors of multidrug-resistant Escherichia coli - the role of similar biological processes despite structural diversity

Multidrug-resistant gram-negative pathogens such as Escherichia coli have become increasingly difficult to treat and therefore alternative treatment options are needed. Targeting virulence factors like biofilm formation could be one such option. Inhibition of biofilm-related structures like curli and cellulose formation in E. coli has been shown for different phenolic natural compounds like epigallocatechin gallate. This study demonstrates this effect for other structurally unrelated phenolics, namely octyl gallate, scutellarein and wedelolactone. To verify whether these structurally different compounds influence identical pathways of biofilm formation in E. coli a broad comparative RNA-sequencing approach was chosen with additional RT-qPCR to gain initial insights into the pathways affected at the transcriptomic level. Bioinformatical analysis of the RNA-Seq data was performed using DESeq2, BioCyc and KEGG Mapper. The comparative bioinformatics analysis on the pathways revealed that, irrespective of their structure, all compounds mainly influenced similar biological processes. These pathways included bacterial motility, chemotaxis, biofilm formation as well as metabolic processes like arginine biosynthesis and tricarboxylic acid cycle. Overall, this work provides the first insights into the potential mechanisms of action of novel phenolic biofilm inhibitors and highlights the complex regulatory processes of biofilm formation in E. coli.

Potential of combining natural-derived antioxidants for improving broiler meat shelf-life - A review

Synthetic antioxidants have shown adverse effects on consumers. The review, thus, aims to assess the effect of marinating broiler meat with plant leaves-derived antioxidants potential for improving shelf-life and human health. Broiler meat loss and waste due to spoilage is more than three million kg annually, thus, extending shelf-life by reducing initial microbial load and autoxidation is essential. Adding various antioxidants would reduce oxidation of protein and fatty acids improving nutritional shelf-life through synergic interactions. Antioxidant synergetic effects also improves reduction in microbiota proliferation leading to the delayed development of off flavours and deterioration of meat colour. To reduce initial microbial load and autoxidation effects, the inclusion of polyphenols and antioxidants from varying sources by mixing various antioxidants would lead to improved synergic effects.

Double-network hydrogel enhanced by SS31-loaded mesoporous polydopamine nanoparticles: Symphonic collaboration of near-infrared photothermal antibacterial effect and mitochondrial maintenance for full-thickness wound healing in diabetes mellitus

Diabetic wound healing has become a serious healthcare challenge. The high-glucose environment leads to persistent bacterial infection and mitochondrial dysfunction, resulting in chronic inflammation, abnormal vascular function, and tissue necrosis. To solve these issues, we developed a double-network hydrogel, constructed with pluronic F127 diacrylate (F127DA) and hyaluronic acid methacrylate (HAMA), and enhanced by SS31-loaded mesoporous polydopamine nanoparticles (MPDA NPs). As components, SS31, a mitochondria-targeted peptide, maintains mitochondrial function, reduces mitochondrial reactive oxygen species (ROS) and thus regulates macrophage polarization, as well as promoting cell proliferation and migration, while MPDA NPs not only scavenge ROS and exert an anti-bacterial effect by photothermal treatment under near-infrared light irradiation, but also control release of SS31 in response to ROS. This F127DA/HAMA-MPDA@SS31 (FH-M@S) hydrogel has characteristics of adhesion, superior biocompatibility and mechanical properties which can adapt to irregular wounds at different body sites and provide sustained release of MPDA@SS31 (M@S) NPs. In addition, in a diabetic rat full thickness skin defect model, the FH-M@S hydrogel promoted macrophage M2 polarization, collagen deposition, neovascularization and wound healing. Therefore, the FH-M@S hydrogel exhibits promising therapeutic potential for skin regeneration.

Antimicrobial resistance (AMR) as a form of human-wildlife conflict: Why and how nondomesticated species should be incorporated into AMR guidance

The challenge of antimicrobial resistance (AMR) continues to receive significant global attention as common infections become increasingly resistant to the drugs used to treat them. Once an infectious microbe has developed a mechanism of resistance, it can cause longer, more damaging infections which are more costly, time-consuming, and sometimes impossible to treat. Such impacts occur across the health of humans, animals, plants, and the environment. Thus, AMR is considered a One Health issue. However, current narratives on AMR focus on humans, food-producing animals, crops, and their immediate environments. Very little attention is given to wildlife in terms of the impact of AMR on their health, nor their role in the evolution and spread of AMR. This article (1) discusses an absence of wildlife in current AMR guidance, (2) suggests how this absence of wildlife could limit understanding of, and action on, AMR, (3) proposes that considering AMR as a form of human-wildlife conflict could enable AMR guidance to better incorporate wildlife into action planning and create a truly One Health approach to tackle AMR.

In vitro inhibition and eradication of multidrug-resistant Acinetobacter baumannii biofilms by riparin III and colistin combination

Acinetobacter baumannii, a prominent emerging pathogen, is responsible for persistent and recurrent healthcare-associated infections (HAIs). Its bacterial resistance and virulence factors, such as biofilm formation, contribute to its survival in hospital environments. Combination therapy has proven to be an effective approach for controlling these infections; however, antimicrobial resistance and compound toxicity can hinder antimicrobial efficacy. Numerous in vitro studies have demonstrated the synergistic effect of antimicrobials and natural products against multidrug-resistant (MDR) A. baumannii biofilm. Riparin III, a natural alkamide derived from Aniba riparia (Nees) Mez., possesses various biological activities, including significant antimicrobial potential. Nonetheless, no reports are available on the use of this compound in conjunction with conventional antimicrobials. Hence, this study aimed to investigate the inhibition and eradication of A. baumannii MDR biofilm by combining riparin III and colistin, along with potential ultrastructural changes observed in vitro. Clinical isolates of A. baumannii, known for their robust biofilm production, were inhibited, or eradicated in the presence of the riparin III/colistin combination. Furthermore, the combination resulted in several ultrastructural alterations within the biofilm, such as elongated cells and coccus morphology, partial or complete disruption of the biofilm's extracellular matrix, and cells exhibiting cytoplasmic material extravasation. At the synergistic concentrations, the riparin III/colistin combination exhibited a low hemolytic percentage, ranging from 5.74% to 6.19%, exerting inhibitory and eradicating effects on the A. baumannii biofilm, accompanied by notable ultrastructural changes. These findings suggest its potential as a promising alternative for therapeutic purposes.

Back to Nature: Medicinal Plants as Promising Sources for Antibacterial Drugs in the Post-Antibiotic Era

Undoubtedly, the advent of antibiotics in the 19th century had a substantial impact, increasing human life expectancy. However, a multitude of scientific investigations now indicate that we are currently experiencing a phase known as the post-antibiotic era. There is a genuine concern that we might regress to a time before antibiotics and confront widespread outbreaks of severe epidemic diseases, particularly those caused by bacterial infections. These investigations have demonstrated that epidemics thrive under environmental stressors such as climate change, the depletion of natural resources, and detrimental human activities such as wars, conflicts, antibiotic overuse, and pollution. Moreover, bacteria possess a remarkable ability to adapt and mutate. Unfortunately, the current development of antibiotics is insufficient, and the future appears grim unless we abandon our current approach of generating synthetic antibiotics that rapidly lose their effectiveness against multidrug-resistant bacteria. Despite their vital role in modern medicine, medicinal plants have served as the primary source of curative drugs since ancient times. Numerous scientific reports published over the past three decades suggest that medicinal plants could serve as a promising alternative to ineffective antibiotics in combating infectious diseases. Over the past few years, phenolic compounds, alkaloids, saponins, and terpenoids have exhibited noteworthy antibacterial potential, primarily through membrane-disruption mechanisms, protein binding, interference with intermediary metabolism, anti-quorum sensing, and anti-biofilm activity. However, to optimize their utilization as effective antibacterial drugs, further advancements in omics technologies and network pharmacology will be required in order to identify optimal combinations among these compounds or in conjunction with antibiotics.

as a Versatile and Predictable Chiral Stationary Phase for the Resolution of Racemic Mixtures

Metal-organic frameworks (MOFs) have become promising materials for multiple applications due to their controlled dimensionality and tunable properties. The incorporation of chirality into their frameworks opens new strategies for chiral separation, a key technology in the pharmaceutical industry as each enantiomer of a racemic drug must be isolated. Here, we describe the use of a combination of computational modeling and experiments to demonstrate that high-performance liquid chromatography (HPLC) columns packed with TAMOF-1 as the chiral stationary phase are efficient, versatile, robust, and reusable with a wide array of mobile phases (polar and non-polar). As proof of concept, in this article, we report the resolution with TAMOF-1 HPLC columns of nine racemic mixtures with different molecular sizes, geometries, and functional groups. Initial in silico studies allowed us to predict plausible separations in chiral compounds from different families, including terpenes, calcium channel blockers, or P-stereogenic compounds. The experimental data confirmed the validity of the models and the robust performance of TAMOF-1 columns. The added value of in silico screening is an unprecedented achievement in chiral chromatography.

Antibacterial Activity of Thesium chinense Turcz Extract Against Bacteria Associated with Upper Respiratory Tract Infections

Purpose

The drug resistance of Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes and Haemophilus influenzae has become more and more serious, and it is urgent to seek new antibacterial drugs. In this study, Thesium chinense Turcz. extracts were tested for its potential antibacterial activities.

Methods

T. chinense powder was extracted with 5 solvents of different polarity (ethyl alcohol, petroleum ether, ethyl acetate, n-butyl alcohol and double distilled water), and their antibacterial activities were tested. The Broth dilution method was used to evaluate the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of highly active plant extracts with a concentration of 1g/mL. The inhibitory activity of this extract on biofilm formation was investigated. Afterwards, we investigated its effect on the transcriptome of S. aureus.

Results

The ethanol extract coded as BRY, only inhibited S. aureus, whereas the ethyl acetate extract coded as BY2 showed inhibitory effect on all the tested bacteria. The MIC of BRY on S. aureus was 128 mg/mL, and the MBC was 512 mg/mL. The MIC of BY2 against S. aureus, S. pneumoniae, S. pyogenes and H. influenzae were 8 mg/mL, 4 mg/mL, 4 mg/mL, and 4 mg/mL, respectively. The MBC of BY2 for these four bacteria ranged from 4 to 256 mg/mL. Mechanism studies have shown that BRY and BY2 have an impact on anti-formation of biofilms at MIC concentrations. Transcriptome sequencing results showed that 531 genes were up-regulated and 340 genes showed down-regulated expression in S. aureus after BY2 treatment.

Conclusion

BY2 has a broader antibacterial spectrum than BRY. Meanwhile, the inhibitory effect of BY2 on S. aureus is better than BRY. The mechanism of BY2 against S. aureus may relate to its inhibition of ribosome synthesis, restriction of key enzymes of citric acid cycle, decrease of pathogenicity and influence on biofilm formation. The results confirmed that BY2 was the main antibacterial part of T. chinense, which can be used as a source of antibacterial agents.

Plant myo-inositol transport influences bacterial colonization phenotypes

Plant microbiomes are assembled and modified through a complex milieu of biotic and abiotic factors. Despite dynamic and fluctuating contributing variables, specific host metabolites are consistently identified as important mediators of microbial interactions. We combine information from a large-scale metatranscriptomic dataset from natural poplar trees and experimental genetic manipulation assays in seedlings of the model plant Arabidopsis thaliana to converge on a conserved role for transport of the plant metabolite myo-inositol in mediating host-microbe interactions. While microbial catabolism of this compound has been linked to increased host colonization, we identify bacterial phenotypes that occur in both catabolism-dependent and -independent manners, suggesting that myo-inositol may additionally serve as a eukaryotic-derived signaling molecule to modulate microbial activities. Our data suggest host control of this compound and resulting microbial behavior are important mechanisms at play surrounding the host metabolite myo-inositol.

Antioxidant, Volatile Compounds; Antimicrobial, Anti-Inflammatory, and Dermatoprotective Properties of Cedrus atlantica (Endl.) Manetti Ex Carriere Essential Oil: In Vitro and In Silico Investigations

Cedrus atlantica (Endl.) Manetti ex Carriere is an endemic tree possessing valuable health benefits which has been widely used since time immemorial in international traditional pharmacopoeia. The aim of this exploratory investigation is to determine the volatile compounds of C. atlantica essential oils (CAEOs) and to examine their in vitro antimicrobial, antioxidant, anti-inflammatory, and dermatoprotective properties. In silico simulations, including molecular docking and pharmacokinetics absorption, distribution, metabolism, excretion, and toxicity (ADMET), and drug-likeness prediction were used to reveal the processes underlying in vitro biological properties. Gas chromatography-mass spectrophotometry (GC-MS) was used for the chemical screening of CAEO. The antioxidant activity of CAEO was investigated using four in vitro complementary techniques, including ABTS and DPPH radicals scavenging activity, ferric reductive power, and inhibition of lipid peroxidation (β-carotene test). Lipoxygenase (5-LOX) inhibition and tyrosinase inhibitory assays were used for testing the anti-inflammatory and dermatoprotective properties. GC-MS analysis indicated that the main components of CAEO are β-himachalene (28.99%), α-himachalene (14.43%), and longifolene (12.2%). An in vitro antimicrobial activity of CAEO was examined against eleven strains of Gram-positive bacteria (three strains), Gram-negative bacteria (four strains), and fungi (four strains). The results demonstrated high antibacterial and antifungal activity against ten of them (>15 mm zone of inhibition) using the disc-diffusion assay. The microdilution test showed that the lowest values of MIC and MBC were recorded with the Gram-positive bacteria in particular, which ranged from 0.0625 to 0.25 % v/v for MIC and from 0.5 to 0.125 % v/v for MBC. The MIC and MFC of the fungal strains ranged from 0.5 to 4.0% (MIC) and 0.5 to 8.0% v/v (MFC). According to the MBC/MIC and MFC/MIC ratios, CAEO has bactericidal and fungicidal activity. The results of the in vitro antioxidant assays revealed that CAEO possesses remarkable antioxidant activity. The inhibitory effects on 5-LOX and tyrosinase enzymes was also significant (p < 0.05). ADMET investigation suggests that the main compounds of CAEO possess favorable pharmacokinetic properties. These findings provide scientific validation of the traditional uses of this plant and suggest its potential application as natural drugs.

Antifungal Activity of Plantago lanceolata and Sida ovata Leaf Extracts against Dermatomycotic Fungi

Plantago lanceolata and Sida ovata have been used as medicinal plants for centuries to cure numerous diseases. This study aimed to evaluate antifungal activity of P. lanceolata and S. ovata leaf extracts against dermatomycotic fungi. Crude extracts from leaves of both plants were prepared using methanol and ethyl acetate. Phytochemical screening of both plants leaves was performed. Antifungal activity of crude extracts was evaluated against three dermatomycotic fungi (Candida albicans, Malassezia furfur, and Malassezia globosa). In addition, minimum inhibitory concentration (MIC) of the extracts was determined by microbroth dilution method. Maximum inhibition zone of 32.00 ± 11.64 mm was exhibited when combined ethyl acetate extract of both plants was applied against M. globosa. Best effect of MIC was demonstrated by ethyl acetate extract against most tested dermatomycotic fungi. Average MIC of ethyl acetate and methanol extracts ranged as follows: (0.19 ± 0.00 to 0.65 ± 0.00 mg/mL and 0.19 ± 0.00 to 0.52 ± 0.22 mg/mL) and (0.65 ± 0.22 to 1.56 ± 0.00 mg/mL and 0.19 ± 0.00 to 0.52 ± 0.00 mg/mL), respectively. Their synergistic effect was better than the effect of individual plant leaf extract. Minimum fungicidal concentration (MFC) values varied across the fungal pathogens when extracts from both plants and their combinations were used. The findings from the current study support the traditional use of P. lanceolata and S. ovata against dermatomycotic fungal infections, which could potentially be exploited for the treatment of superficial infection in humans.

Biochemical, Antioxidant Properties and Antimicrobial Activity of Steno-Endemic Origanum onites

Origanum onites (Lamiaceae) is an Eastern Mediterranean plant that is widely used in Turkish traditional medicine. This study aimed to investigate the biochemical composition, antimicrobial activity, and antioxidant potential of O. onites. In this study, the biochemical composition of the O. onites ethanol extract (OOEt) was analyzed using GC-MS. The antimicrobial activity was investigated using a disk diffusion test and determining minimum inhibitory concentrations (MIC) against 30 microorganism strains, including 28 bacteria (some multidrug-resistant) and 2 fungi. Additionally, the antioxidant activity was evaluated using the DPPH method. The main component identified was carvacrol. OOEt demonstrated antimicrobial activity against a wide range of tested microorganism strains. OOEt displayed the highest activity against E. faecium (a Gram-positive bacterium) at 100 µL with a 52 mm inhibition zone. Additionally, P. aeruginosa DSMZ 50071 and P. fluorescens P1, which are Gram-negative bacteria, were the most sensitive strains with a 24 mm inhibition zone in 100 µL of OOEt. The data obtained from A. baumannii (a multidrug-resistant strain) is particularly striking, as higher activity was observed compared to all positive controls. All tested fungal strains showed more effective results than positive controls. The antioxidant activity of OOEt was found to be stronger than that of the positive control, ascorbic acid. This study determined that O. onites has significant antimicrobial and antioxidant potential.

Effects of Cuminum cyminum L. essential oil and its nanoemulsion on oxidative stability and microbial growth in mayonnaise during storage

The present study aimed to investigate the effects of Cuminum cyminum L. essential oil (CEO) and its nanoemulsion (CEON) on oxidative stability and microbial growth of mayonnaise during storage. The GC analysis indicated that Cuminaldehyde (27.99%), o-Cymene (17.31%), γ-Terpinen (16.67%), and β-Pinene (9.35%) were the major components of CEO, respectively. The assessments of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) showed that Escherichia coli ATCC 25922 (MBCCEO = 12 and MBCCEON = 6 mg/mL) was the most resistant bacteria, and in contrast, Staphylococcus aureus ATCC 29213 (MBCCEO = 6 and MBCCEON = 3 mg/mL) was the most sensitive bacteria. In the radical-scavenging assay, CEON (IC50 = 5 ± 0.07 μg/mL) exhibited a higher antioxidant activity than CEO (IC50 = 10 ± 0.13 μg/mL). The results showed that applying the MBC of CEO and CEON in mayonnaise led to a significant decrease (p < .05) in acidity, peroxide value, number of acid-resistant bacteria and fungi, and total microbial count compared with the control sample. In conclusion, this study demonstrated that using CEON resulted in oxidative stability, microbial growth control, and desirable sensorial attributes in mayonnaise compared with CEO and control samples.

Caenorhabditis elegans as an In Vivo Model for the Discovery and Development of Natural Plant-Based Antimicrobial Compounds

Antimicrobial resistance (AMR) due to the prevalence of multidrug-resistant (MDR) pathogens is rapidly increasing worldwide, and the identification of new antimicrobial agents with innovative mechanisms of action is urgently required. Medicinal plants that have been utilised for centuries with minor side effects may hold great promise as sources of effective antimicrobial products. The free-living nematode Caenorhabditis elegans (C. elegans) is an excellent live infection model for the discovery and development of new antimicrobial compounds. However, while C. elegans has widely been utilised to explore the effectiveness and toxicity of synthetic antibiotics, it has not been used to a comparable extent for the analysis of natural products. By screening the PubMed database, we identified articles reporting the use of the C. elegans model for the identification of natural products endowed with antibacterial and antifungal potential, and we critically analysed their results. The studies discussed here provide important information regarding "in vivo" antimicrobial effectiveness and toxicity of natural products, as evaluated prior to testing in conventional vertebrate models, thereby supporting the relevance of C. elegans as a highly proficient model for their identification and functional assessment. However, their critical evaluation also underlines that the characterisation of active phytochemicals and of their chemical structure, and the unravelling of their mechanisms of action represent decisive challenges for future research in this area.

Exploring the antibacterial potential of plant extracts and essential oils against Bacillus thermophilus in beet sugar for enhanced sucrose retention: a comparative assessment and implications

Sugar beet is one of the greatest sources for producing sugar worldwide. However, a group of bacteria grows on beets during the storage process, leading to a reduction in sucrose yield. Our study focused on identifying common bacterial species that grow on beets during manufacturing and contribute to sucrose loss. The ultimate goal was to find a potential antibacterial agent from various plant extracts and oils to inhibit the growth of these harmful bacteria and reduce sucrose losses. The screening of bacterial species that grow on beet revealed that a large group of mesophilic bacteria, such as Bacillus subtilis, Leuconostoc mesenteroides, Pseudomonas fluorescens, Escherichia coli, Acinetobacter baumannii, Staphylococcus xylosus, Enterobacter amnigenus, and Aeromonas species, in addition to a dominant thermophilic species called Bacillus thermophilus, were found to be present during the manufacturing of beets. The application of 20 plant extracts and 13 different oils indicated that the extracts of Geranium gruinum, Datura stramonium, and Mentha spicata were the best antibacterials to reduce the growth of B. thermophilus with inhibition zones equal to 40, 39, and 35 mm, respectively. In contrast, the best active oils for inhibiting the growth of B. thermophilus were Mentha spicata and Ocimum bacilicum, with an inhibitory effect of 50 and 45 mm, respectively. RAPD-PCR with different primers indicated that treating sugar juice with the most effective oils against bacteria resulted in new recombinant microorganisms, confirming their roles as strong antibacterial products. The characterization of Mentha spicata and Ocimum bacilicum oils using GC/MS analysis identified cis-iso pulegone and hexadecanoic acid as the two main bioactive compounds with potential antibacterial activity. An analysis of five genes using DD-PCR that have been affected due to antibacterial activity from the highly effective oil from Mentha spicata concluded that all belonged to the family of protein defense. Our findings indicate that the application of these pure antibacterial plant extracts and oils would minimize the reduction of sucrose during sugar production.

Galactoside-Based Molecule Enhanced Antimicrobial Activity through Acyl Moiety Incorporation: Synthesis and In Silico Exploration for Therapeutic Target

In this study, a series of galactoside-based molecules, compounds of methyl β-d-galactopyranoside (MDGP, 1), were selectively acylated using 2-bromobenzoyl chloride to obtain 6-O-(2-bromobenzoyl) substitution products, which were then transformed into 2,3,4-tri-O-6-(2-bromobenzoyl) compounds (2-7) with various nontraditional acyl substituents. The chemical structures of the synthesized analogs were characterized by spectroscopic methods and physicochemical and elemental data analyses. The antimicrobial activities of the compounds against five human pathogenic bacteria and two phyto-fungi were evaluated in vitro and it was found that the acyl moiety-induced synthesized analogs exhibited varying levels of antibacterial activity against different bacteria, with compounds 3 and 6 exhibiting broad-spectrum activity and compounds 2 and 5 exhibiting activity against specific bacteria. Compounds 3 and 6 were tested for MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) based on their activity. The synthesized analogs were also found to have potential as a source of new antibacterial agents, particularly against gram-positive bacteria. The antifungal results suggested that the synthesized analogs could be a potential source of novel antifungal agents. Moreover, cytotoxicity testing revealed that the compounds are less toxic. A structure-activity relationship (SAR) investigation revealed that the lauroyl chain [CH₃(CH₂)₁₀CO-] and the halo-aromatic chain [3(/4)-Cl.C₆H₄CO-] in combination with sugar, had the most potent activity against bacterial and fungal pathogens. Density functional theory (DFT)-calculated thermodynamic and physicochemical parameters, and molecular docking, showed that the synthesized molecule may block dengue virus 1 NS2B/NS3 protease (3L6P). A 150 ns molecular dynamic simulation indicated stable conformation and binding patterns in a stimulating environment. In silico ADMET calculations suggested that the designed (MDGP, 1) had good drug-likeness values. In summary, the newly synthesized MDGP analogs exhibit potential antiviral activity and could serve as a therapeutic target for dengue virus 1 NS2B/NS3 protease.

The Use of Natural Bioactive Nutraceuticals in the Management of Tick-Borne Illnesses

The primary objective of this paper is to provide an evidence-based update of the literature on the use of bioactive phytochemicals, nutraceuticals, and micronutrients (dietary supplements that provide health benefits beyond their nutritional value) in the management of persistent cases of Borrelia burgdorferi infection (Lyme disease) and two other tick-borne pathogens, Babesia and Bartonella species. Recent studies have advanced our understanding of the pathophysiology and mechanisms of persistent infections. These advances have increasingly enabled clinicians and patients to utilize a wider set of options to manage these frequently disabling conditions. This broader toolkit holds the promise of simultaneously improving treatment outcomes and helping to decrease our reliance on the long-term use of pharmaceutical antimicrobials and antibiotics in the treatment of tick-borne pathogens such as Borrelia burgdorferi, Babesia, and Bartonella.

Preparation and Application of Active Bionanocomposite Films Based on Sago Starch Reinforced with a Combination of TiO2 Nanoparticles and Penganum harmala Extract for Preserving Chicken Fillets

The aim of this study was to develop sago starch-based bionanocomposite films containing TiO₂ nanoparticles and Penganum harmala extract (PE) to increase the shelf life of chicken fillets. First, sago starch films containing different levels of TiO₂ nanoparticles (1, 3, and 5%) and PE (5, 10, and 15%) were prepared. The barrier properties and antibacterial activity of the films against different bacteria strains were investigated. Then, the produced films were used for the chicken fillets packaging, and the physicochemical and antimicrobial properties of fillets were estimated during 12-day storage at 4 °C. The results showed that the addition of nano TiO₂ and PE in the films increased the antibacterial activity against gram-positive (S. aureus) higher than gram-negative (E. coli) bacteria. The water vapor permeability of the films decreased from 2.9 to 1.26 (×10^-11 g/m·s·Pa) by incorporating both PE and nano TiO₂. Synergistic effects of PE and nano TiO₂ significantly decreased the oxygen permeability of the sago starch films from 8.17 to 4.44 (cc.mil/m²·day). Application results of bionanocomposite films for chicken fillet storage at 4 °C for 12 days demonstrated that the films have great potential to increase the shelf life of fillets. The total volatile basic nitrogen (TVB-N) of chicken fillets increased from 7.34 to 35.28 after 12 days, whereas samples coated with bionanocomposite films increased from 7.34 to 16.4. For other physicochemical and microbiological properties of chicken fillets, similar improvement was observed during cold storage. It means that the bionanocomposite films could successfully improve the shelf life of the chicken fillets by at least eight days compared to the control sample.

Assessing Contact Time and Concentration of Thymus vulgaris Essential Oil on Antibacterial Efficacy In Vitro

The overuse and misuse of antibiotics can pose the risk of spreading mutant strains that show antimicrobial resistance (AMR), with negative impacts on the management of bacterial infections and economic implications for healthcare systems. The research and development of natural antibacterial agents could be a priority in the next years to improve a number of effective antibacterial molecules and to reduce the AMR phenomenon and its development. The present study identified the most effective concentration and contact time of Thymus vulgaris L. essential oil (TEO) to obtain bactericidal effects in vitro against different Gram-positive and Gram-negative bacterial strains. Six clinically isolated (wild types) bacterial strains, (Citrobacter freundii, Enterococcus feciorum, Proteus mirabilis, Acinetobacter cioffi, Pseudomonas putrefaciens and Klebsiella pneumoniae) and two ATCCs (Staphylococcus aureus and Streptococcus mutans) were tested after 1 min, 3 min and 5 min of contact with TEO. The preliminary results on S. aureus after 24 h of incubation revealed a TEO concentration of 9.28 mg/mL (w/v) that completely inhibited bacteria growth, keeping cell viability. The total suppression of bacterial growth at all tested contact times was observed for all tested bacterial strains, and the results were confirmed after 48 h of incubation. Bacterial growth suppression was confirmed even with the presence of organic components. These preliminary results showed the in vitro antimicrobial efficacy of TEO against different Gram-positive and Gram-negative bacterial strains. Future studies are necessary to confirm the reproducibility of these results even on other strains and to define the exact molecular mechanisms of EOs in order to consider TEO as a valid alternative to classic antibiotic therapies and subsequently to reduce the occurrence of AMR.