Antioxidant and antimicrobial phenolic compounds from extracts of cultivated and wild-grown Tunisian Ruta chalepensis

Antibacterial and Antioxidant Activities of Hydroalcoholic and Phenolic Extracts from Ternstroemia dentisepala and T. lineata Leaves

Traditional Mexican medicine commonly uses infusions of Ternstroemia spp. to treat insomnia, injuries, and infections. The antibacterial activities of Ternstroemia dentisepala and Ternstroemia lineata were evaluated for the first time against a panel of Gram-positive and Gram-negative bacteria that have implications for human health, including Enterococcus faecalis, Streptococcus agalactiae, Streptococcus pyogenes, Salmonella typhi, Pseudomonas aeruginosa, and Vibrio parahaemolyticus. Furthermore, the scavenging potential of the hydroalcoholic (HAEs) and total phenolic extracts (TPEs) from the leaves of both plants by a 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assay (ABTS•+) was determined. Also, the total phenolic contents of the HAEs using the Folin-Ciocalteu reagent were assayed. T. dentisepala HAE and TPE were active against all bacterial strains tested, with a minimum inhibitory concentration between 1.0 and 6.0 mg/mL, with the last one being the most active. However, the T. lineata extracts only demonstrated effectiveness against S. typhi and P. aeruginosa. The TPEs from T. dentisepala and T. lineata improved the activity by approximately 30% in all bacteria tested in comparison with the HAEs. The T. dentisepala HAE had a higher total phenolic content than the T. lineata extract, which was consistent with its ABTS•+-scavenging activity. The two HAEs had different chemical profiles, mostly because of the types and amounts of phenolic compounds they contained. These profiles were obtained using thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), and proton nuclear magnetic resonance (1H NMR) experiments.

Chemical Composition, Antioxidant, and Antibacterial Activity of Ruta chalepensis L. Ethanolic Extract

Ruta chalepensis L. is a versatile herb used in culinary arts and traditional medicine. The study aimed to determine the chemical composition of an ethanolic extract from R. chalepensis and the total phenolic and flavonoid content. Additionally, the extracts' antimicrobial and antioxidant activities were tested. The disc diffusion method and minimum inhibitory concentration (MIC) were used to test the antibacterial properties on four types of bacteria: Escherichia coli, Proteus penneri, Bacillus cereus, and Staphylococcus aureus. A colorimetric assay was used to evaluate the total phenolic and flavonoid content, and the DPPH method was used to assess the antioxidant activity. The phytochemical constituents were determined using LC-MS/MS. The results indicated that R. chalepensis ethanolic extract had 34 compounds, and the predominant compounds were quercetin (9.2 %), myricetin (8.8 %), and camphene (8.0 %). Moreover, the extract had a good level of polyphenols and flavonoids, as demonstrated by inhibiting free radicals (DPPH) (IC50 was 41.2±0.1). Also, the extract exhibited robust antimicrobial activity against P. penneri and S. aureus with an MIC of 12.5 and 25.0 μg/mL, respectively. In conclusion, the results suggest that the R. chalepensis ethanolic extract has good antioxidant and antibacterial properties that could be utilized to develop new antibacterial agents.

Gaafar AR, Gurusamy R, Akbar I. Synthesis of anthraquinone-connected coumarin derivatives via grindstone method and their evaluation of antibacterial, antioxidant, tyrosinase inhibitory activities with molecular docking, and DFT calculation studies

Anthraquinones and coumarins have excellent pharmacological activities and are an important class of natural plant metabolites with various biological activities. In this study, anthraquinone-9,10-dione and coumarin derivatives were combined to develop a novel anthraquinone-connected coumarin-derivative sequence. The synthesised novel anthraquinone-connected coumarin derivatives (1a-t) were screened for in vitro antibacterial, antioxidant, and tyrosinase inhibitory activities. The antibacterial activities of the synthesised compounds (1a-t) were tested against both gram-positive and gram-negative bacteria. Specifically, compound 1t was more active against E. aerogenes than ciprofloxacin. With regard to antioxidant activity, compound 1o (50.68 % at 100 μg/mL) was highly active compared to the other compounds, whereas it was less active than the standard BHT (76.74 % at 100 μg/mL). In terms of compound 1r (9.31 ± 0.45 μg/mL) was highly active against tyrosinase inhibitory activity compared with kojic acid (10.42 ± 0.98 μg/mL). In the molecular docking study, compound 1r had a higher docking score (-8.8 kcal mol-1) than kojic acid (-1.7 kcal mol-1). DFT calculations were performed to determine the energy gap of highly active compound 1r (ΔE = 0.11) and weakly active compound 1a (ΔE = 0.12). In this study, we found that every molecule displayed significant antibacterial, antioxidant, and tyrosinase inhibitory properties. Based on these reports, compounds 1r and 1t may act as multi-target agents.

Potential Protective Effects of Ruta Chalepensis L. Extracts Against Gentamicin-Induced Nephrotoxicity via Reduction on Apoptotic, DNA Damage and Oxidative Stress Markers in Mice

In this study, the protective effects of Ruta chalepensis L. extracts on the extent of tissue damage in gentamicin-induced nephrotoxicity have been investigated. Ruta chalepensis L. extracts were prepared by subcritical water and ultrasound-assisted organic solvent extraction methods. Protective activity of Ruta chalepensis L. extracts on Gentamicin-induced nephrotoxicity is investigated by apoptotic, DNA damage, oxidative stress markers and evaluating histopathological in kidney tissue of mice. Gentamicin significantly increased Caspase-3 and -8 activities, NO levels, serum creatinine and BUN, while 8-OHdG and MDA levels were significantly decreased with Ruta chalepensis L. extract treatment. In addition, Ruta chalepensis L. extracts treatment significantly increased CAT and SOD activities. Histopathological alterations in Gentamicin group were significantly diminished by application of Ruta chalepensis L. extracts. These results suggest that treatment with Ruta chalepensis L. extracts may ameliorate renal dysfunction and structural damage through the reduction of oxidative stress and apoptosis in the kidney.

Challenges and advances in biotechnological approaches for the synthesis of canolol and other vinylphenols from biobased p-hydroxycinnamic acids: a review

p-Hydroxycinnamic acids, such as sinapic, ferulic, p-coumaric and caffeic acids, are among the most abundant phenolic compounds found in plant biomass and agro-industrial by-products (e.g. cereal brans, sugar-beet and coffee pulps, oilseed meals). These p-hydroxycinnamic acids, and their resulting decarboxylation products named vinylphenols (canolol, 4-vinylguaiacol, 4-vinylphenol, 4-vinylcatechol), are bioactive molecules with many properties including antioxidant, anti-inflammatory and antimicrobial activities, and potential applications in food, cosmetic or pharmaceutical industries. They were also shown to be suitable precursors of new sustainable polymers and biobased substitutes for fine chemicals such as bisphenol A diglycidyl ethers. Non-oxidative microbial decarboxylation of p-hydroxycinnamic acids into vinylphenols involves cofactor-free and metal-independent phenolic acid decarboxylases (EC 4.1.1 carboxyl lyase family). Historically purified from bacteria (Bacillus, Lactobacillus, Pseudomonas, Enterobacter genera) and some yeasts (e.g. Brettanomyces or Candida), these enzymes were described for the decarboxylation of ferulic and p-coumaric acids into 4-vinylguaiacol and 4-vinylphenol, respectively. The catalytic mechanism comprised a first step involving p-hydroxycinnamic acid conversion into a semi-quinone that then decarboxylated spontaneously into the corresponding vinyl compound, in a second step. Bioconversion processes for synthesizing 4-vinylguaiacol and 4-vinylphenol by microbial decarboxylation of ferulic and p-coumaric acids historically attracted the most research using bacterial recombinant phenolic acid decarboxylases (especially Bacillus enzymes) and the processes developed to date included mono- or biphasic systems, and the use of free- or immobilized cells. More recently, filamentous fungi of the Neolentinus lepideus species were shown to natively produce a more versatile phenolic acid decarboxylase with high activity on sinapic acid in addition to the others p-hydroxycinnamic acids, opening the way to the production of canolol by biotechnological processes applied to rapeseed meal. Few studies have described the further microbial/enzymatic bioconversion of these vinylphenols into valuable compounds: (i) synthesis of flavours such as vanillin, 4-ethylguaiacol and 4-ethylphenol from 4-vinylguaiacol and 4-vinylphenol, (ii) laccase-mediated polymer synthesis from canolol, 4-vinylguaiacol and 4-vinylphenol.

Chemical composition, antioxidant and antibacterial activity of Piper chaba stem extracts with preservative effects on storage of raw beef patties

Piper chaba, a traditional South-east Asian medicinal herb and well-known curry spice, was studied to evaluate its suitability as a source of natural preservatives for beef products. Plant extracts that are high in phenolics and have high antimicrobial and antioxidant activities are likely to be useful as a natural preservative. Therefore, the phytochemical composition and the bioactivities of both ethanolic and methanolic extracts of P. chaba stem were examined first. The study revealed a significant antioxidant activities and potential antibacterial activity of P. chaba extracts. Next we investigated the preservation characteristics of P. chaba by using beef patties as a model system. Beef patties were produced and treated with 0.2 % ethanolic extract (mentioned as PEE) of P. chaba and 0.1 % commercial preservative (mentioned as PCP). They were then assessed for various storage quality parameters under refrigerated (4° C ± 1° C) conditions, including free fatty acid, antioxidant contents, and oxidative stability at 0, 6th, 16th, and 33rd days. No significant variations were observed across the products with regard to proximate composition study such as protein, ash and fat contents. In comparison to both PEE and PCP, the control product had higher free fatty acid values throughout the storage period. This indicates that the fat content of the PEE and PCP degraded at a slower rate than the control over the 33-day storage period. Our study also showed that both PCP and PEE had increased antioxidant capacity, implying that lipid oxidation is minimized. In contrast to the control, the oxidative stability of the P. chaba treated products was also higher. Altogether this study revealed that P. chaba could be utilized commercially, particularly in the food industry to preserve muscle foods.

Practical Applications

Natural preservatives are becoming more popular as a result of the different carcinogenic and toxic side effects of conventional preservatives. P. chaba, an exquisite culinary herb in Bangladesh, has long been used as a traditional medicine, because of its antimicrobial and antioxidant properties. This study revealed that P. chaba can be utilized as a food preservative, which opens up new possibilities for its development and use in functional foods.

Ruta angustifolia Pers. (Narrow-Leaved Fringed Rue): Pharmacological Properties and Phytochemical Profile

The genus Ruta in the family Rutaceae includes about 40 species, such as the well-known plants R. graveolens L. (common rue) or R. chalepensis L. (fringed rue), but also much lesser-known species such as R. angustifolia Pers. (narrow-leaved fringed rue). This rue specie, originating from the Mediterranean region, is well-distributed in Southeast Asia, notably in the Indo-Chinese peninsula and other territories. In some countries, such as Malaysia, the plant is used to treat liver diseases and cancer. Extracts of R. angustifolia display antifungal, antiviral and antiparasitic effects. Diverse bioactive natural products have been isolated from the aerial parts of the plant, notably quinoline alkaloids and furocoumarins, which present noticeable anti-inflammatory, antioxidant and/or antiproliferative properties. The present review discusses the main pharmacological properties of the plant and its phytoconstituents, with a focus on the anticancer activities evidenced with diverse alkaloids and terpenoids isolated from the aerial parts of the plant. Quinoline alkaloids such as graveoline, kokusaginine, and arborinine have been characterized and their mode of action defined. Arborinine stands as a remarkable inhibitor of histone demethylase LSD1, endowed with promising anticancer activities. Other anticancer compounds, such as the furocoumarins chalepin and rutamarin, have revealed antitumor effects. Their mechanism of action is discussed together with that of other bioactive natural products, including angustifolin and moskachans. Altogether, R. angustifolia Pers. presents a rich phytochemical profile, fully consistent with the traditional use of the plant to treat cancer. This rue species, somewhat neglected, warrant further investigations as a medicinal plant and a source of inspiration for drug discovery and design.

Ruta chalepensis L. In Vitro Cultures as a Source of Bioactive Furanocoumarins and Furoquinoline Alkaloids

Recently, due to the decreasing areas of cultivation and climate change, the use of biotechnological methods to obtain biomass, which is a source of valuable bioactive metabolites, is becoming more and more interesting. In this study, Ruta chalepensis in vitro cultures were investigated in RITA^® temporary immersion bioreactors. Biomass growth and the production of secondary metabolites in 4- and 5-week growth cycles on three variants of the Linsmaier and Skoog (LS) medium (naphthyl-1-acetic acid/6-benzylaminopurine (NAA/BAP): 0.5/1.0, 0.1/0.1, and 1.0/1.0 mg/L) were analyzed. Using high-performance liquid chromatography of methanolic extracts of biomass, the presence of linear furanocoumarins (bergapten, isoimperatorin, isopimpinellin, psoralen, and xanthotoxin) and furoquinoline alkaloids (γ-fagarine, 7-isopentenyloxy-γ-fagarine, and skimmianine) was confirmed. The highest content of linear furanocoumarins (1170 mg/100 g DW (dry weight)) was observed in the LS medium variant containing 0.5/1.0 mg/L NAA/BAP (4-week growth cycle). The highest content of furoquinoline alkaloids (449 mg/100 g DW) was observed in the LS medium variant containing 0.1/0.1 mg/L NAA/BAP (5-week growth cycle). Hence, R. chalepensis bioreactor cultures may be used as a biotechnological source of linear furanocoumarins (xanthotoxin and bergapten) and furoquinoline alkaloids (skimmianine and γ-fagarine).

Valorization of Quercus suber L. Bark as a Source of Phytochemicals with Antimicrobial Activity against Apple Tree Diseases

Cork, an anatomic adaptation of the bark of Quercus suber L. through its suberization process, finds its main application in the production of bottle stoppers. Its processing results in a large waste stream of cork fragments, granulates, and dust, which may be susceptible to valorization. The work presented here explored the use of its extracts to inhibit the growth of phytopathogenic microorganisms associated with apple tree diseases. The in vitro antimicrobial activity of cork aqueous ammonia extract was assayed against four fungi, viz. Monilinia fructigena and M. laxa (brown rot), Neofussicoccum parvum (dieback), and Phytophthora cactorum (collar and root rot), and two bacteria, viz. Erwinia amylovora and Pseudomonas syringae pv. syringae, either alone or in combination with chitosan oligomers (COS). Effective concentration values of EC₉₀ in the 675-3450 μg·mL^-1 range, depending on the fungal pathogen, were obtained in growth inhibition tests, which were substantially improved for the conjugate complexes (340-801 μg·mL^-1) as a result of strong synergism with COS. Similar enhanced behavior was also observed in antibacterial activity assays, with MIC values of 375 and 750 μg·mL^-1 for the conjugate complexes against P. syringae pv. syringae and E. amylovora, respectively. This in vitro inhibitory activity was substantially higher than those exhibited by azoxystrobin and fosetyl-Al, which were tested for comparison purposes, and stood out among those reported for other natural compounds in the literature. The observed antimicrobial activity may be mainly attributed to the presence of glycerin and vanillic acid, identified by gas chromatography-mass spectroscopy. In the first step towards in-field application, the COS-Q. suber bark extract conjugate complex was further tested ex situ against P. cactorum on artificially inoculated excised stems of the 'Garnem' almond rootstock, achieving high protection at a dose of 3750 μg·mL^-1. These results suggest that cork industrial leftovers may, thus, be a promising source of bioactive compounds for integrated pest management.

Total Flavonoids Extracts of Apocynum L. from the Ili River Valley Region at Different Harvesting Periods and Bioactivity Analysis

In the current study, the total content from two Apocynum species leaves (Apocynum venetum and Apocynum hendersonii) collected from the Ili River Valley Region were extracted, and their bioactivities were investigated. The results showed a significant variation in the total flavonoid contents in the leaf samples collected at different periods (June, July, August, and September), with the highest content in August (60.11 ± 0.38 mg RE/g DW for A. venetum and 56.56 ± 0.24 mg RE/g DW for A. hendersonii), and the lowest in June (22.36 ± 0.05 mg RE/g DW for A. venetum and 20.79 ± 0.02 mg RE/g DW for A. hendersonii). The total flavonoid content was comparably higher in A. venetum than in A. hendersonii. Leaves extracts from the two species demonstrated strong bioactivity, which positively correlated with the total flavonoid contents. The anti-oxidative activity of A. venetum was higher than that of A. hendersonii in tandem with its higher flavonoid contents; the antibacterial activity, however, was conversely opposite. Furthermore, a total of 83 flavonoid metabolites were identified in the two species based on UPLC-ESI-MS/MS, out of which 24 metabolites were differentially accumulated. The variability in these metabolites might be the reason for the different bioactivities displayed by the two species. The present study provides insight into the optimal harvest time for Apocynum species planted in the major distribution area of the Ili River Valley and the specific utilization of A. venetum and A. hendersonii.

Source dependent variation in phenolics, antioxidant and antimicrobial activity of Paeonia emodi in west Himalaya, India

Paeonia emodi is one of the ethno therapeutically important Himalayan plants used to cure various diseases. However, a systematic investigation of the effect of altitude on phytochemical, antioxidant, and antimicrobial activity has not been reported so far. The present study assessed the variation in the bioactive compounds, antioxidant and antimicrobial activity of the leaf, and rhizome of P. emodi collected from different altitudes. Phytochemicals such as phenols, flavonoids, flavanol, tannins, emodin, and paeoniflorin were found in all the sampled populations, but the quantity varied significantly across the altitude. In leaf, phenolics, flavonoids, and tannins content positively correlated with altitude (p < 0.01), but flavanol did not show any connection. Similarly, in the rhizome, positive relation with altitude (p < 0.01) was observed in phenol, flavonoids, and paeoniflorin. Antioxidant activity measured by 1, 1-diphenyl- 2 picrylhydrazyl (DPPH) and nitric oxide assays showed a positive correlation (p < 0.05) with altitude. 2, 2-azinobis (3-ethylbenzothiazoline-6-sulphonic acid), ferric reducing antioxidant power, and hydroxyl ion assays did not show any relation with altitude. Antimicrobial activity was higher in the case of rhizome for the minimum inhibitory concentration and positively correlated with phenolics, flavonoids, and flavanol (p < 0.05). The present study further revealed that the secondary metabolites in the leaf and rhizome extracts of P. emodi are an excellent source of antioxidant and antimicrobial activity, thus validating the species' therapeutic potential.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-022-01242-z.

Phytochemical Composition, Antioxidant, Antibacterial, and Enzyme Inhibitory Activities of Various Organic Extracts from Apocynum hendersonii (Hook.f.) Woodson

Apocynum hendersonii is a traditional medicinal plant used primarily as tea. It has a potential health benefit from its rich bioactive substances. This study investigated the reactivity of solvents of different polarities (ethanol, ethyl acetate, n-hexane, methanol, and water) extracts of the A. hendersonii leaf. The phytochemical composition of the extracts was evaluated using a Fourier Transform Infrared spectrophotometer (FT-IR), Gas Chromatography-Mass Spectrometry (GC-MS), UHPLC-MS, and Higher Performance Liquid Chromatography (HPLC). The result revealed the presence of medicinally important bioactive constituents, including phenols, flavonoids, and polysaccharides. Methanol extracts exhibited the highest flavonoid contents (20.11 ± 0.85 mg QE/g DW) and the second-highest in terms of phenolic (9.25 ± 0.03 mg GAE/g DW) and polysaccharide (119.66 ± 2.65 mg GE/g DW). It also had the highest antioxidant capacity with 60.30 ± 0.52% and 4.60 ± 0.02 µmol Fe²⁺ per g DW based on a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and ferric reducing antioxidant power (FRAP), respectively. Ethanol extract displayed the maximum antibacterial action against Gram-negative and Gram-positive bacteria and the highest inhibition activity against the enzymes tyrosinase and acetylcholinesterase, followed by methanol extract. The principal component analysis revealed a positive correlation between the constituents, bioactivities, and extracts. The overall result showed A. hendersonii as a rich natural source of antimicrobial and antioxidant bioactive compounds and may be used for future applications in pharmaceuticals and food industries.

Phenolic Characterization Using cLC-DAD Analysis and Evaluation of In Vitro and In Vivo Pharmacological Activities of Ruta tuberculata Forssk

The perennial aromatic plant Ruta tuberculata Forssk (Rutaceae) has been traditionally used by Mediterranean peoples as folk medicine against several types of disease to treat diverse illness. The objective of this work is to evaluate the in vitro and in vivo pharmacological activities of the aqueous (RAE) and methanolic (MeOH) 80% (RME) extracts of Algerian R. tuberculata aerial parts. Antioxidant potential, neuro-protective and anti-arthritic activities were investigated in vitro using six antioxidant approaches and by determining acetyl-cholinesterase and bovine albumin denaturation inhibitory capacities, respectively. Furthermore, in vivo anti-ulcer and anti-inflammatory activities were evaluated on EtOH-induced gastric mucosal damage and carrageenan-induced paw edema models in mice. Moreover, bio-compounds’ contents were also quantified using spectrophotometric and cLC-DAD methods. Both in vivo and in vitro investigations showed remarkable antioxidant activity of Ruta tuberculata Forssk, while methanolic extract (RME) of Ruta tuberculata Forssk exhibited more significant neuro-protective and anti-inflammatory effects. However, the antiulcer activity was more pronounced with RAE of R. tuberculata, which suggests that this plant can be considered as a natural resource of potent bioactive compounds that may act as antioxidant and anti-inflammatory agents, which underlines the importance of incorporating them in therapies in order to treat various diseases linked to oxidative stress, and they may also provide crucial data for the development of new anticholinesterase drugs to improve neurodegenerative diseases, such as Alzheimer’s.

A Candidate for Health Promotion, Disease Prevention and Treatment, Common Rue (Ruta graveolens L.), an Important Medicinal plant in Traditional Medicine

BACKGROUND

Ruta graveolens L. belongs to Rutaceae; it is a semi-wood perennial or a small evergreen sub-shrub, which is native to Southern Europe, West of Asia and Northern Africa.

OBJECTIVE

The goal of this manuscript was to outline the most notable traditional and modern advantages and pharmaceutical benefits of common rue.

METHODS

The manuscript covers review articles, randomized control experiments, analytical studies and observations, which have been gathered from different sources such as Google Scholar, Scopus, Science Direct and PubMed. A review of the literature was carried out using the keywords rutin, Ruta graveolens L., rue, common rune, coumarin, natural products and pharmaceutical benefits.

RESULTS

Rue contains quinoline alkaloids, such as graveoline and graveolinine, acridone alkaloids, such as furacridone and gravacridone, the furanoquinoline dictamnine, coumaris, such as gravelliferone, isorutarin, rutacultin, rutaretin, and suberenone, and the furanocoumarins 5-methoxypsoralen (bergapten) and 8-methoxypsoralen (xanthotoxine). Most of its aromatic and medicinal properties are from its rutin, and essential oil. It has been used in folk medicines as a stimulant, anti-inflammatory and analgesic properties, anti-androgenic activity, anti-hyperglycemic effects, anti-hyperlipidemic effects, xanthine oxidase inhibition activity, anticancer properties.

CONCLUSION

According to pharmacological and phytochemical advantages, pennyroyal shows its importance as a medicinal plant in both modern medicinal science and traditional medicine.

Insights into the Antimicrobial, Antioxidant, Anti-SARS-CoV-2 and Cytotoxic Activities of Pistacia lentiscus Bark and Phytochemical Profile; In Silico and In Vitro Study

Foodborne infections and antibiotic resistance pose a serious threat to public health and must be addressed urgently. Pistacia lentiscus is a wild-growing shrub and has been utilized for medicinal applications as well as for culinary purposes. The antibacterial and antioxidant activities of P. lentiscus bark in vitro, as well as the phytochemical composition, are the focus of this inquiry. The bark extract of P. lentiscus showed significant antimicrobial activity in experiments on bacteria and yeast isolated from human and food sources. The exposure time for the complete inhibition of cell viability of P. aeruginosa in the extracts was found to be 5% at 15 min. Phytochemical inquiry of the methanol extract demonstrates the existence of carbohydrates, flavonoids, tannins, coumarins, triterpenes, and alkaloids. Deep phytochemical exploration led to the identification of methyl gallate, gallic acid, kaempferol, quercetin, kaempferol 3-O-α-rhamnoside, kaempferol 3-O-β-glucoside, and Quercetin-3-O-β-glucoside. When tested using the DPPH assay, the methanol extracts of P. lentiscus bark demonstrated a high free radical scavenging efficiency. Further, we have performed a molecular modelling study which revealed that the extract of P. lentiscus bark could be a beneficial source for novel flavonoid glycosides inhibitors against SARS-CoV-2 infection. Taken together, this study highlights the Pistacia lentiscus bark methanol extract as a promising antimicrobial and antiviral agent.

Spent Coffee Grounds Valorization as Bioactive Phenolic Source Acquired Antifungal, Anti-Mycotoxigenic, and Anti-Cytotoxic Activities

Spent coffee grounds (SCGs), which constitute 75% of original coffee beans, represent an integral part of sustainability. Contamination by toxigenic fungi and their mycotoxins is a hazard that threatens food production. This investigation aimed to examine SCGs extract as antimycotic and anti-ochratoxigenic material. The SCGs were extracted in an eco-friendly way using isopropanol. Bioactive molecules of the extract were determined using the UPLC apparatus. The cytotoxicity on liver cancer cells (Hep-G2) showed moderate activity with selectivity compared with human healthy oral epithelial (OEC) cell lines but still lower than the positive control (Cisplatin). The antibacterial properties were examined against pathogenic strains, and the antifungal was examined against toxigenic fungi using two diffusion assays. Extract potency was investigated by two simulated models, a liquid medium and a food model. The results of the extract showed 15 phenolic acids and 8 flavonoids. Rosmarinic and syringic acids were the most abundant phenolic acids, while apigenin-7-glucoside, naringin, epicatechin, and catechin were the predominant flavonoids in the SCGs extract. The results reflected the degradation efficiency of the extract against the growth of Aspergillus strains. The SCGs recorded detoxification in liquid media for aflatoxins (AFs) and ochratoxin A (OCA). The incubation time of the extract within dough spiked with OCA was affected up to 2 h, where cooking was not affected. Therefore, SCGs in food products could be applied to reduce the mycotoxin contamination of raw materials to the acceptable regulated limits.

High-Frequency Plant Regeneration, Genetic Uniformity, and Flow Cytometric Analysis of Regenerants in Rutachalepensis L

Ruta chalepensis L., an evergreen shrub in the citrus family, is well-known around the world for its essential oils and variety of bioactivities, indicating its potential medicinal applications. In this study, we investigated the effect of different culture conditions, including plant growth regulators, media types, pH of the medium, and carbon sources, on in vitro regeneration from nodal explants of R. chalepensis. Following 8 weeks of culture, the highest percentage of regeneration (96.3%) and maximum number of shoots (40.3 shoot/explant) with a length of 4.8 cm were obtained with Murashige and Skoog (MS) medium at pH 5.8, supplemented with 3.0% sucrose and 5.0 µM 6-Benzyladenine (BA) in combination with 1.0 µM 1-naphthaleneacetic acid (NAA). For rooting, individually harvested shootlets were transferred on ½ MS (half-strength) supplemented with IAA (indole-3-acetic acid), IBA (indole 3-butyric acid), or NAA, and the best response in terms of root induction (91.6%), number of roots (5.3), and root mean length (4.9 cm) was achieved with 0.5 µM IBA after 6 weeks. An average of 95.2 percent of healthy, in vitro regenerated plantlets survived after being transplanted into potting soil, indicating that they were effectively hardened. DNA assays (PCR-based markers) such as random amplification of polymorphic DNA (RAPD) and directed amplification of minisatellite-region (DAMD) were employed to assess in vitro cultivated R. chalepensis plantlets that produced a monomorphic banding pattern confirming the genetic stability. Additionally, no changes in the flow cytometric profile of ploidy between regenerated plantlets and donor plants were detected. Regeneration of this valuable medicinal plant in vitro will open up new avenues in pharmaceutical biotechnology by providing an unconventional steadfast system for mass multiplication and might be effectively used in genetic manipulation for enhanced bioactive constituents.

Highly recyclable Ti0.97Ni0.03O1.97 catalyst coated on cordierite monolith for efficient transformation of arylboronic acids to phenols and reduction of 4-nitrophenol

A stable Ni²⁺ substituted TiO₂ catalyst (Ti_0.97Ni_0.03O_1.97) has been synthesized by a solution combustion method with an average crystallite size of 7.5 nm. Ti_1-xNi_xO_2-x (x = 0.01-0.06) crystallizes in the TiO₂ anatase structure with Ni²⁺ substituted in Ti⁴⁺ ion sites and Ni taking a nearly square planar geometry. This catalyst is found to be highly active in the transformation of diverse arylboronic acids to the corresponding phenols. The catalyst coated cordierite monolith can even be recycled for up to 20 cycles with a cumulative TOF of 1.8 × 10⁵ h^-1. In scale-up reactions, various phenols are synthesized by employing a single cordierite monolith. It also shows high performance in the reduction of 4-nitrophenol.

Anti-enterococcal and anti-oxidative potential of a thermophilic cyanobacterium, Leptolyngbya sp. HNBGU 003

Enterococci, the opportunistic pathogens, pose several serious and life-threatening infections such as urinary tract infections, sepsis, and endocarditis. The situation is worsening due to the development of drug resistance in these pathogens against several antibiotics. The addition of anti-enterococcal compounds with antioxidant activity in fermented and packaged food may help prevent the transmission of food-borne enterococcal infections. Scientists are in continuous search of such compounds from various sources. Hence, the present study has tested the diethyl ether extracts of thermophilic cyanobacteria, selected based on a previous study, against the multidrug-resistant and -sensitive strains of Enterococcus faecium. Out of the eleven tested extracts, 72% have shown anti-enterococcal activity against both strains. Among the extracts with anti-enterococcal activity, the diethyl ether extract of Leptolyngbya sp. (DEEL-3) inhibited the growth of VRE in a dose-dependent manner with a minimum inhibitory concentration of 2.0 mg mL^-1. The DEEL-3 has also shown its antioxidant potential in terms of DPPH scavenging with an IC₅₀ of 3.16 mg mL^-1. The organism was named Leptolyngbya sp. HNBGU 003 based on 16SrRNA sequence homology analysis and morphological features. Further, the GC–MS analysis of the DEEL-3 has revealed the predominance of two phenolic compounds, phenol, 2,4-bis(1,1-dimethylethyl)-, phosphite (3:1) and tris(2,4-di-tert-butylphenyl) phosphate, in it. Thus, the anti-enterococcal and antioxidant activity of DEEL-3 may be attributed to these phenolics, which may be isolated and developed as food additives.

Multivariate analysis of adaptive response to ferulic acid and p-coumaric acid after physiological stresses in Cronobacter sakazakii

AIM

The present study demonstrated the antimicrobial activity of ferulic acid and p-coumaric acid against unstressed and stressed (cold stressed, starved and desiccated) Cronobacter sakazakii in laboratory media (37°C) and reconstituted powdered infant formulation (PIF) with mild heat treatment (50°C).

METHODS AND RESULTS

Five phenolics, namely, quercetin, rutin, caffeic acid, ferulic acid and p-coumaric acid, were tested for antimicrobial activities against five strains of C. sakazakii either unstressed or stressed. Strain specific higher resistance to ferulic acid and p-coumaric acid was observed after stress adaptation in laboratory media. The effect of cross protection was validated using reconstituted PIF as delivery vehicle of selected compounds. Both p-coumaric acid and ferulic acid showed inhibition of C. sakazakii in a dose and time dependent manner as revealed by their viable cell counts. Principal component analysis revealed that the desiccated cells were more sensitive to phenolics in reconstituted PIF.

CONCLUSIONS

Only ferulic acid and p-coumaric acid showed marked antibacterial activity with minimum inhibitory concentration in the range of 2·5-5 mg ml^-1 for unstressed C. sakazakii cells in tryptone soy broth. The maximum inhibition was achieved with 20 mg ml^-1 of both the tested polyphenols in reconstituted PIF. Cold stress and starvation stress did not impart any protection nor increased the susceptibility of C. sakazakii, whereas desiccation resulted in increased susceptibility to phenolic compounds.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results obtained in this study helps in understanding the effect of environmental stresses during processing on susceptibility of C. sakazakii to natural antimicrobial agents. Future transcriptomic studies and functional genetic studies are warranted to understand the strain specific stress responses for the development of better control methods possibly by using these natural antagonists.

Misuse, consequences and phototoxic skin-related effects of Rutaceae: a comprehensive literature review

Ruta is a common plant growing in Italy and in the Mediterranean area. It has been used in popular tradition with different aims, ranging from therapeutic to esoteric purposes. However, the plant is still used as a common remedy in some of present-day rural and urban communities and it can be found in gardens all over Europe. Ruta's photosensitizing effect has been described in the literature and seems to be mediated by furanocoumarins. We collected data from the 18 case-reports for a total of 32 patients that we included in our analysis, assessing demographic variables, clinical findings, diagnosis, time of onset of lesions, time of resolution and therapy. The main aim of this work was to outline the clinical presentation, therapeutic management and demography of phytophototoxic reactions from contact with Ruta in order to suggest the correct diagnostic approach and disease recognition, as well as its possible prevention.

Synergistic and Antagonistic Effects of Biogenic Silver Nanoparticles in Combination With Antibiotics Against Some Pathogenic Microbes

The latest advances in green nanoparticle synthesis have preserved natural and non-renewable resources and decreased environmental pollution. The current study was designed to evaluate silver nanoparticles (AgNPs) fabricated using aqueous extracts of two medicinal plants, Anastatica hierochuntica L. (Kaff Maryam) and Artemisia absinthium. The phytochemicals were detected by Fourier-transform infrared spectroscopy (FTIR) and Chromatography/Mass Spectrometry (GC-MS). The effects of the AgNPs on Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Candida albicans as well as the cytotoxicity against MDA-MB-231 cells were examined. The synergistic and antagonistic effects of the biogenic AgNPs in combination with standard antibiotics against several microbes were also investigated. The ability of the plant extracts to transfer silver ions to AgNPs was measured via dynamic light scattering, zeta potential measurement, and transmission electron microscopy. The most sensitive microbes to AgNP treatment were examined via scanning electron microscopy to assess morphological changes. Biogenic AgNPs showed significant antibacterial effects against most of the tested microbes and significant cytotoxicity was noted. Polysaccharides, proteins and Phenolic compounds are likely involved in AgNP biosynthesis since hydroxyl groups and amides were detected via FTIR as well as GC-MS. This study confirmed that plant-based AgNP fabrication with AgNO₃ as the Ag (I) delivering salt can be an economical and practical approach for large-scale production of particles with antimicrobial and cytotoxic potential. The synergistic effects of biogenic AgNPs in combination with some antibiotics support their potential as a safe therapeutic for bacterial infections because they are capped with organic biomolecules.

Antimicrobial Potential of Biosynthesized Silver Nanoparticles by Aaronsohnia factorovskyi Extract

The green biosynthesis of nanoparticles by plant extracts is an attractive and promising technique for medicinal applications. In the current study, we chose one of the daisy plants, Aaronsohnia factorovskyi (which grows in the Najd region, Saudi Arabia), to investigate its anti-microbial efficacy, in combination with silver nanoparticles. The biosynthesized nanoparticles were evaluated for antibacterial activity against Staphylococcus aureus, Bacillussubtilis (Gram-positive), Pseudomonas aeruginosa, and Escherichia coli, (Gram-negative) using the disc diffusion method, while the antifungal activity was assessed against Fusarium oxysporum, Fusarium solani, Helminthosporiumrostratum, and Alternariaalternata. The potential phytoconstituents of the plant extracts were identified by Fourier-transform infrared spectroscopy (FT-IR) techniques, the Field emission scanning electron microscopy (FE-SEM), Chromatography/Mass Spectrometry (GC-MS) techniques, and Zeta potential analysis. The current study revealed the ability of the tested plant extract to convert silver ions to silver nanoparticles with an average diameter of 104–140 nm. Biogenic Aaronsohnia factorovskyi-silver nanoparticles (AF-AgNPs) showed significant antibacterial activity against Staphylococcus aureus with inhibition zone diameter to 19.00 ± 2.94 mm, and antifungal activity against Fusarium solani, which reduced the growth of fungal yarn to 1.5 mm. The innovation of the present study is that the green synthesis of NPs, which is simple, cost-effective, provides stable nano-materials, and can be an alternative for the large-scale synthesis of silver nanoparticles.

4-O-methylascochlorin attenuates inflammatory responses induced by lipopolysaccharide in RAW 264.7 macrophages

Inflammation is implicated in various diseases, such as inflammatory bowel disease and cancer. Ascochlorin (ASC) and its derivatives have been shown to modulate inflammatory responses in many previous studies. However, the effects of 4-O-methylascochlorin (MAC), one of the ASC derivatives, on inflammatory responses have yet to be reported. In addition, the consequences of chemical modification of ASC on protein signaling and immunity have yet to be fully understood. The fourth carbon in MAC is methylated, which may result in modulation of immune response differently compared with ASC. Hence, we have investigated the role of MAC in inflammatory response induced by lipopolysaccharide in murine macrophage cells. Here, we found that MAC treatment decreased the inflammatory response by murine macrophages. When murine macrophages were treated with MAC, the transcription and translation of various pro-inflammatory indicators such as iNOS and COX-2 decreased. In addition, the ELISA results showed that the expression of TNF-α, IL-6, and IL-1β, which are pro-inflammatory cytokines, was successfully decreased by MAC. Such effects of MAC appear to be mediated via downregulation of MAPK signaling and the transactivational activity of NF-κB. Lipopolysaccharide upregulates MAPK protein phosphorylation and NF-κB translocation, which in turn enhances the transactivation of genes related to NF-κB. Such results of lipopolysaccharide were attenuated by MAC. Collectively, our results indicate that MAC alleviated the inflammatory responses induced by lipopolysaccharide in murine macrophages successfully by modulating MAPK signaling pathway and NF-κB-related genes. This study shows that MAC, similar to other ASC derivatives, can potentially be used therapeutically to reduce the harmful damage induced by prolonged inflammation. In addition, the structural differences between ASC and its derivatives as well as their effect on intracellular signaling will also be discussed.

In-vitro antioxidant, anti-cancer, and anti-inflammatory activities of selected medicinal plants from western Nepal

Background

This study was focused on the measurement of anticancer properties of six medicinal plants from western Nepal in three cell lines; HeLa, Hep3B, and HCT116, and anti-inflammatory properties in RAW 264.7 cell line through NO, PGE2, and TNF-α production. In addition, the phytochemical screening, total phenolic, flavonoid content, and antioxidant properties were evaluated.

Results

The qualitative phytochemical analysis revealed the presence of different secondary metabolite and range of total phenolic and total flavonoid content. The highest antioxidant activities were observed in Bergenia pacumbis against both DPPH (IC50 = 25.97 ± 0.19 μg/mL) and ABTS (IC50 = 14.49 ± 0.40 μg/mL). Furthermore, the highest antiproliferative effect against cervical, liver, and colon cancer cell lines were observed in Melia azedarach as IC50 values of 10.50, 5.30, and 1.57 μg/mL respectively, while the strongest anti-metastatic potential on liver cancer cell line was found in Pleurospermum benthamii. In addition, P. benthamii showed the most potent anti-inflammatory effect in RAW264.7 murine macrophage cells.

Conclusion

This study provided the evidence for M. azedarach and P. benthamii to have great anticancer potential and finding builds the enough scientific backgrounds in future to isolate and purify the bioactive compounds for further applications.

Genome-wide transcriptome variation landscape in Ruta chalepensis organs revealed potential genes responsible for rutin biosynthesis

Ruta chalepensis L., most commonly known as 'fringed rue,' is an excellent and valuable bioactive plant that produces a range of complex flavonoids, of which rutin is the major compound present in this plant of great pharmaceutical and medicinal significance. The present study is a pioneering attempt to examine the changes in the transcriptomic landscape of leaf, stem, and root tissues and correlate this with rutin quantity in each tissue in order to identify the candidate genes responsible for rutin biosynthesis and to increase genomic resources in fringed rue. Comparative transcriptome sequencing of leaves, stems and roots were performed using the NovaSeq 6000 platform. The de novo transcriptome assembly generated 254,685 transcripts representing 154,018 genes with GC content of 42.60 % and N50 of 2280 bp. Searching assembled transcripts against UniRef90 and SwissProt databases annotated 79.7 % of them as protein coding. The leaf tissues had the highest rutin content followed by stems and roots. Several differentially expressed genes and transcripts relating to rutin biosynthesis were identified in leaves comparing with roots or stems comparing with roots. All the genes known to be involved in rutin biosynthesis showed up-regulation in leaves as compared with roots. These results were confirmed by gene ontology (GO) and pathway enrichment analyses. Up-regulated genes in leaves as compared with roots enriched GO terms with relation to rutin biosynthesis e.g. action of flavonol synthase, biosynthetic mechanism of malonyl-CoA, and action of monooxygenase. Phylogenetic analysis of the rhamnosyltransferase (RT) gene showed that it was highly homologues with RT sequence from Citrus species and all were located in the same clade. This transcriptomic dataset will serve as an important public resource for future genomics and transcriptomic studies in R. chalepensis and will act as a benchmark for the identification and genetic modification of genes involved in the biosynthesis of secondary metabolites.

Cochlospermum regium (Schrank) pilger leaf extract inhibit methicillin-resistant Staphylococcus aureus biofilm formation

ETHNOPHARMACOLOGICAL RELEVANCE

Cochlospermum regium, known as "algodãozinho", is an important plant belonging to Brazilian biodiversity used in traditional medicine to treat infections, wounds and skin conditions.

AIM OF THE STUDY

To assess the effects of aqueous and ethanolic extracts from C. regium leaves on methicillin-resistant Staphylococcus aureus planktonic cells and biofilm formation.

MATERIAL AND METHODS

The phytochemical characterization of the extracts was carried out by quantification of flavonoids, phenols and tannins and HPLC-DAD. Minimum inhibitory concentrations, cell viability, and enzyme activity inhibition were determined in planktonic cells exposed to C. regium extracts. The effect of the extracts on biofilms was assessed by quantifying colony-forming units (CFUs) and the extracellular matrix, and by visualizing the biofilm structure using scanning electron microscopy.

RESULTS

Leaf extract contents showed high concentration of phenols and the gallic and ellagic acids were identified. The extracts showed potent antimicrobial activities at concentrations ranging from 62.5-250 μg/mL, and decreased coagulase activity. In addition, the extracts prevented biofilm formation, and the aqueous extract completely inhibited its formation.

CONCLUSIONS

C. regium extracts stand out as promising alternative treatments for the prevention and treatment of methicillin-resistant Staphylococcus aureus infections.

Genus Ruta: A natural source of high value products with biological and pharmacological properties

ETHNOPHARMACOLOGICAL RELEVANCE

Ruta genus is constituted by ten species, of which the most commonly described are R. chalepensis and R. graveolens. Ruta plants are perennial shrubs belonging to the family Rutaceae, which are traditionally used in folk medicine, since ancient times mostly for the treatment of various ailments of the womb.

AIM OF THE STUDY

To provide a review of the different uses of Ruta species in traditional medicine, as well as, on their multifactorial biological and pharmacological properties.

MATERIAL AND METHODS

A search of the literature on genus Ruta and Ruta species was performed using various scientific databases and search engines and the information of articles were reviewed and compiled.

RESULTS

Different parts of the plants belonging to Ruta genus are used in folk medicine to treat a wide range of different diseases. The principal use of these is in gynaecological field, but the treatment of pain, fever, nausea, inflammation, infections, nervous disorders, among others, are also described. These plants have been used to fertility regulation, as anti-fertility agent, to control menstrual flux and bleedings, as abortifacient and as contraceptive. The phytochemical composition of these plants consists mainly in essential oil (EO), but phenolic compounds were also reported, like coumarins and flavonoids, as well as alkaloids. Ruta species products like extracts and EOs have shown broad pharmacological activities, such as antimicrobial and antifungal activities, as well as, antiviral and antiparasitic. Moreover, Ruta plants products present antioxidant, neuroprotective, anti-inflammatory, anti-cancer and anti-diabetic activities and demonstrated contraceptive and abortifacient effects. These plants were also tested to be used for non-therapeutic approaches, as bio-insecticides in the control of different insect pests showing to be able to reduce infestation.

CONCLUSIONS

Ruta species could be a potential source of natural products with biological activities. Ruta extracts, essential oils and isolated compounds have shown a diverse potential for use in the treatment of different diseases, as well as, for pests control, contributing to the valorisation of these plants. Nonetheless, this review indicates that more studies are needed to demonstrate the full potential of Ruta species, and to further explore the toxicology and safety of these plants.

Antioxidant and antimicrobial applications of biopolymers: A review

Biopolymers have generated mounting interest among researchers and industrialists over the recent past. Rising consciousness on the use of eco-friendly materials as green alternatives for fossil-based biopolymers has shifted the research focus towards biopolymers. Advances in technologies have opened up new windows of opportunities to explore the potential of biopolymers. In this context, this review presents a critique on applications of biopolymers in relation to antioxidant and antimicrobial activities. Some biopolymers are reported to contain inherent antioxidant and antimicrobial properties, whereas, some biopolymers, which do not possess such inherent properties, are used as carriers for other biopolymers or additives having these properties. Modifications are often performed in order to improve the properties of biopolymers to suit them for different applications. This review aims at presenting an overview on recent advances in the use of biopolymers with special reference to their antioxidant and antimicrobial applications in various fields.

Comparative inhibitory effects of 4-allylpyrocatechol isolated from Piper betle on Streptococcus intermedius, Streptococcus mutans, and Candida albicans

Streptococcus intermedius, Streptococcus mutans, and Candida albicans are harmful oral pathogens and prone to resist chemical antimicrobial agents. Active ingredients from plants are of increasing interest as an alternative. This study aims to compare antimicrobial effects of 4-allylpyrocatechol (APC) extracted from Piper betle on these oral pathogens. Minimum concentration of APC against the tested pathogens was determined using a broth microdilution assay. Killing kinetic study of APC was carried out within 24 h. Morphology of the pathogenic cells was assessed using scanning electron microscopy (SEM). Anti-biofilm was investigated using crystal violet assay and confocal laser scanning microscopy (CLSM). The results showed that the mechanism of inhibition of APC was bactericidal and fungicidal effects. APC at minimum concentration of 400 μg/mL could completely kill Streptococcus and Candida spp., however, the killing rate on S. intermedius and C. albicans was significantly faster than on S. mutans. APC inhibited biofilm formation of C. albicans more efficiently than that of the bacterial cells. Cell morphology from SEM indicated that APC caused bacterial cell membrane destruction and inhibited fungal budding or tubing formation. CLSM images confirmed the killing potential of APC and suggested that bacterial dead cells could be easier washed out than the fungal dead cells. It is concluded that APC potentially inhibits growth and biofilms of oral Streptococcus and Candida spp. in different mechanism of action and killing rate. APC can be considered as a promising agent for preventing and treating dental disorders caused by S. intermedius, S. mutans, and C. albicans.

Plant Phenolics and Phenolic-Enriched Extracts as Antimicrobial Agents against Food-Contaminating Microorganisms

Phenolic compounds and extracts with bioactive properties can be obtained from many kinds of plant materials. These natural substances have gained attention in the food research as possible growth inhibitors of foodborne pathogenic and spoilage bacteria. Many phenolic-enriched plant extracts and individual phenolics have promising anti-quorum sensing potential as well and can suppress the biofilm formation and toxin production of food-related pathogens. Various studies have shown that plant phenolics can substitute or support the activity of synthetic food preservatives and disinfectants, which, by the way, can provoke serious concerns in consumers. In this review, we will provide a brief insight into the bioactive properties, i.e., the antimicrobial, anti-quorum sensing, anti-biofilm and anti-enterotoxin activities, of plant phenolic extracts and compounds, with special attention to pathogen microorganisms that have food relation. Carbohydrase aided applications to improve the antimicrobial properties of phenolic extracts are also discussed.

Antibacterial Properties of Polyphenols: Characterization and QSAR (Quantitative Structure-Activity Relationship) Models

Besides their established antioxidant activity, many phenolic compounds may exhibit significant antibacterial activity. Here, the effect of a large dataset of 35 polyphenols on the growth of 6 foodborne pathogenic or food-spoiling bacterial strains, three Gram-positive ones (Staphylococcus aureus, Bacillus subtilis, and Listeria monocytogenes) and three Gram-negative ones (Escherichia coli, Pseudomonas aeruginosa, and Salmonella Enteritidis), have been characterized. As expected, the effects of phenolic compounds were highly heterogeneous ranging from bacterial growth stimulation to antibacterial activity and depended on bacterial strains. The effect on bacterial growth of each of the polyphenols was expressed as relative Bacterial Load Difference (BLD) between a culture with and without (control) polyphenols at a 1 g L-1 concentration after 24 h incubation at 37°C. Reliable Quantitative Structure-Activity Relationship (QSAR) models were developed (regardless of polyphenol class or the mechanism of action involved) to predict BLD for E. coli, S. Enteritidis, S. aureus, and B. subtilis, unlike for L. monocytogenes and P. aeruginosa. L. monocytogenes was generally sensitive to polyphenols whereas P. aeruginosa was not. No satisfactory models predicting the BLD of P. aeruginosa and L. monocytogenes were obtained due to their specific and quite constant behavior toward polyphenols. The main descriptors involved in reliable QSAR models were the lipophilicity and the electronic and charge properties of the polyphenols. The models developed for the two Gram-negative bacteria (E. coli, S. Enteritidis) were comparable suggesting similar mechanisms of toxic action. This was not clearly observed for the two Gram-positive bacteria (S. aureus and B. subtilis). Interestingly, a preliminary evaluation by Microbial Adhesion To Solvents (MATS) measurements of surface properties of the two Gram-negative bacteria for which QSAR models were based on similar physico-chemical descriptors, revealed that MATS results were also quite similar. Moreover, the MATS results of the two Gram-positive bacterial strains S. aureus and B. subtilis for which QSARs were not based on similar physico-chemical descriptors also strongly differed. These observations suggest that the antibacterial activity of most of polyphenols likely depends on interactions between polyphenols and bacterial cells surface, although the surface properties of the bacterial strains should be further investigated with other techniques than MATS.

Assessment of Total Phenolic Content, In Vitro Antioxidant and Antibacterial Activity of Ruta graveolens L. Extracts Obtained by Choline Chloride Based Natural Deep Eutectic Solvents

Rue (R. graveolens) has been an extensively studied medicinal plant due to its rich phytochemicals content, such as furanocoumarins and flavonoids. The aim of this study was to determine the effects of varying extraction conditions on the total phenolic content, the antioxidant and antibacterial property of rue leaves crude extracts using deep eutectic solvents with different water content. These extraction conditions include the temperature and the extraction time. The extract obtained at 30 °C, with 20% water and at 90 min, with 13.3 µg mL-1 concentration, was found to possess the highest total phenolic content (38.24 ± 0.11 mg of GAE g-1 of DM) and the highest antioxidant activity (72.53 ± 0.31%). In this study, the same extract showed the best antibacterial efficiency against all the tested strains, especially gram-negative P. aeruginosa.

Comparative Phytochemical Profiles and Antioxidant Enzyme Activity Analyses of the Southern Highbush Blueberry (Vaccinium corymbosum) at Different Developmental Stages

In this study, the fruit quality, anthocyanin content and antioxidant enzyme activities of skin and pulp of southern blueberries (Vaccinium corymbosum) from China y at five developmental stages (green, pink, red, purple and blue) were investigated and anthocyanins were characterized and quantified by HPLC during the considered developmental stages. The results indicatated that the contents of phenolic, flavonoids and anthocyanin as well as antioxidant enzyme activities varied depending on the developmental stages. The correlation values between total phenolic content (TPC), total flavonoids content (TFC) and total anthocyanin content (TAC) were significant. The highest activity of peroxidase (POD) and catalase (CAT) was found in red fruit, and the variety of monomeric anthocyanin increased gradually, skin from blue fruit possessed higher TAC. However, the highest activity of polyphenol oxidase (PPO) and superoxide dismutase (SOD) were detected in green and blue fruit, respectively. In the present work, the differences regarding phytochemical profiles and antioxidant enzyme activities were mainly correlated with developmental stages of fruit.

Radical Scavenging and Antioxidant Activity of Anthyllis Vulneraria Leaves and Flowers

The main targets of this work were to determine the phenolic content of Anthyllis vulneraria (A. vulneraria) leaves and flowers and to evaluate their antioxidant activity. Total polyphenols and flavonoid content (TPC and TFC, respectively) were determined. Antioxidant capacity was evaluated by the Ferric Reducing Antioxidant Power (FRAP), the Oxygen Radical Absorbance Capacity (ORAC), the Trolox Equivalent Antioxidant Capacity (TEAC) and the diphenyl picrylhydrazyl (DPPH) assays, and by the analysis of primary and secondary oxidation products in oil-in-water emulsions and in raw beef patties during storage. The results revealed that the flowers of the A. vulneraria contained the highest content of total polyphenols and flavonoids and extracts from these tissues exhibited the strongest antioxidant activity, as they were more effective at retarding lipid oxidation in oil-in-water emulsions and raw beef patties than extracts from the leaves which had a potent antioxidant effect only at the beginning of the oxidation process. The results of this study allowed us to obtain a deep knowledge about the properties of A. vulneraria and confirmed the possibility of using its biologically active extracts in the food, cosmetic and pharmaceutical industries.

4- O -Caffeoylquinic acid as an antioxidant marker for mulberry leaves rich in phenolic compounds

Mulberry (Morus alba L.) leaves are widely used as herbal tea to prevent heat stroke. Potential chemical markers of the antioxidant properties and its correlation with harvesting times and leaf location were explored in this study. A 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay guided isolation of mulberry leaves extract provided five phenolic compounds: 5-O-caffeoylquinic acid (1), 4-O-caffeoylquinic acid (2), gastrodin (3), isoquercetin (4) and rutin (5). The 50% radical-scavenging concentrations (SC₅₀) of these compounds were 32.76 ± 0.27, 11.41 ± 0.48, 404.30 ± 4.92, 10.63 ± 0.96, and 10.57 ± 0.61 μg/mL, respectively. Chromatographic fingerprinting allowed content analysis of 1–5 in samples over a 12-month period. Compounds 1–5 were abundance in apical leaves (0–10 cm) in January and February at temperatures < 20 °C. Contents of 2 and 5 were highest in these months and were strongly correlated to the antioxidant property. Therefore, we suggested that the mulberry leaves harvested during January and February have high yield of 4-O-caffeoylquinic acid and this compound can be used as antioxidative marker in mulberry leaves.

Determination of carnosic acid in Rosmarinus officinalis L. using square wave voltammetry and electrochemical behavior

A new, fast, sensitive and simple voltammetric method is established for the direct determination of carnosic acid (CA). And the electroreduction of carnosic acid (CA) was studied using electrochemical methods. The number of electrons transferred in electrode mechanisms were calculated for reversible and adsorption-controlled electrochemical reduction of CA at 17 mV versus Ag/AgCl at pH 7.0 in Britton–Robinson buffer (BR) on a hanging mercury drop electrode. Square-wave voltammetry was developed and validated for direct determination of CA. Square-wave parameters were optimized as accumulation potential = 0.0 mV, accumulation time = 5 s, frequency = 50 Hz, pulse amplitude = 50 mV, and staircase step potential = 5 mV. The developed method displays three linear responses from 2 to 9 μM, 10 to 30 and 40 to 90 μM for carnosic acid with a correlation coefficient of 0.996, 0.999 and 0.999. The detection limits were found to be 1.5 μM, 4.0 μM and 40.1 μM, respectively. The interference effect of most common organic and inorganic species was investigated. Proposed method was successfully applied for determination of CA in natural extract of rosemary and the average content was determined as 11.9 ± 1.0 (μg CA/1 g rosemary). The results were in agreement with that obtained by HPLC-UV comparison method. The developed method can be widely used in routine quality control of herbal materials as well as other in foods, medicinal, pharmaceutical and environmental analysis.