Screening antifungal activities of selected medicinal plants

Molecular identification and management of mycotoxigenic fungi in stored corn Grains

Mycotoxin-producing molds which considered as common maize grains contaminants are the genera Fusarium, Aspergillus and Penicillium. There are natural and safe ways to protect grains from mold contamination as the use of essential oils and chemical treatments. A total number of 25 samples were used to study the natural frequency in five governorates in Egypt, Molecular identification indicated that the most frequent fungi were Fusarium verticillioides, Aspergillus niger, Talaromyces verruculosus, Aspergillus flavus and Aspergillus terreus. The in vitro studies have been done to determine mycelial growth and spore germination inhibition of the two A. flavus; isolated and reference isolates. Thyme and acetic acid were tested in direct contact assay to study their effects on mycelial growth. Treatments showed significant impact on mycelial growth and spore germination inhibition of both A. flavus isolates. In the postharvest application treatments: as vapour and carrier contact assay, Thyme and Acetic acid were tested to determine their influence on growth and aflatoxin production in A. flavus isolates by liquid chromatography–electrospray ionization–tandem mass spectrometry (LC–ESI–MS/MS). Results indicated that both treatments were effective in inhibition of aflatoxin production in both vapour and carrier assays as they succeeded in reducing AFB1 while they inhibited completely the production of AFB2. The extent of the inhibition of aflatoxin production was dependent on the concentration and storage duration of treatments applied.

Enhanced Antioxidant, Antifungal, and Herbicidal Activities through Bioconversion of Diosgenin by Yarrowia lipolytica P01a

This study explores the bioconversion of diosgenin by Yarrowia lipolytica P01a, focusing on enhancing the antioxidant, antifungal, and herbicidal activities of the resulting extracts. The bioconversion process, involving glycosylation and hydroxylation, produced significant amounts of protodioscin and soyasaponin I. The extracts showed superior antioxidant activity, with up to 97.02% inhibition of ABTS· radicals and 33.30% inhibition of DPPH· radicals at 1000 mg L-1 of diosgenin. Antifungal assays revealed strong inhibitory effects against Botrytis cinerea, Alternaria sp., and Aspergillus niger, with maximum inhibition rates of 67.34%, 35.63%, and 65.53%, respectively. Additionally, the herbicidal activity of the bioconverted extracts was comparable to commercial herbicides, achieving 100% inhibition of seed germination in both monocotyledonous and dicotyledonous plants. These findings suggest that the Y. lipolytica P01a-mediated bioconversion of diosgenin could provide a sustainable and eco-friendly alternative for developing natural biofungicides and bioherbicides.

Antifungal capabilities of gut microbial communities of three dung beetle species (Scarabaeidae: Scarabaeinae)

Gut microbial communities are part of the regulatory array of various processes within their hosts, ranging from nutrition to pathogen control. Recent evidence shows that dung beetle's gut microbial communities release substances with antifungal activity. Because of the enormous diversity of gut microorganisms in dung beetles, there is a possibility of discovering novel compounds with antifungal properties. We tested the antifungal activity mediated by gut microbial communities of female dung beetles against nine phytopathogenic fungi strains (Colletotrichum asianum-339, C. asianum-340, C. asianum-1, C. kahawae-390, C. karstii-358, C. siamense-220, Fusarium oxysporum-ATCC338, Nectria pseudotrichia-232, Verticillium zaelandica-22). Our tests included the gut microbial communities of three species of dung beetles: Canthon cyanellus (roller beetle), Digitonthophagus gazella (burrower beetle), and Onthophagus batesi (burrower beetle), and we followed the dual confrontation protocol, i.e., we challenged each fungal strain with the microbial communities of each species of beetles in Petri dishes containing culture medium. Our results showed that gut microbial communities of the three dung beetle species exhibit antifungal activity against at least seven of the nine phytopathogenic fungal strains. The gut microbial communities of Onthophagus batesi significantly decreased the mycelial growth of the nine phytopathogenic fungi strains; the gut microbial communities of Canthon cyanellus and Digitonthophagus gazella significantly reduced the mycelial growth of seven strains. These results provide a basis for investigating novel antifungal substances within gut microbial communities of dung beetles.

Hemolysis by Saponin Is Accelerated at Hypertonic Conditions

Saponins are a large group of organic amphiphilic substances (surfactants) mainly extracted from herbs with biological activity, considered as one of the main ingredients in numerous remedies used in traditional medicine since ancient times. Anti-inflammatory, antifungal, antibacterial, antiviral, antiparasitic, antitumor, antioxidant and many other properties have been confirmed for some. There is increasing interest in the elucidation of the mechanisms behind the effects of saponins on different cell types at the molecular level. In this regard, erythrocytes are a very welcome model, having very simple structures with no organelles. They react to changing external conditions and substances by changing shape or volume, with damage to their membrane ultimately leading to hemolysis. Hemolysis can be followed spectrophotometrically and provides valuable information about the type and extent of membrane damage. We investigated hemolysis of erythrocytes induced by various saponin concentrations in hypotonic, isotonic and hypertonic media using measurements of real time and end-point hemolysis. The osmotic pressure was adjusted by different concentrations of NaCl, manitol or a NaCl/manitol mixture. Unexpectedly, at a fixed saponin concentration, hemolysis was accelerated at hypertonic conditions, but was much faster in NaCl compared to mannitol solutions at the same osmotic pressure. These findings confirm the colloid-osmotic mechanism behind saponin hemolysis with pore formation with increasing size in the membrane.

Synthesis, Characterization, and Evaluation of Antifungal Activity of 1-Butyl-3-hexyl-1H-imidazol-2(3H)-selenone by Surface-Enhanced Raman Spectroscopy

In the present research work, a selenium N-heterocyclic carbene (Se-NHC) complex/adduct was synthesized and characterized by using different analytical methods including FT-IR, 1HNMR, and 13CNMR. The antifungal activity of the Se-NHC complex against Aspergillus flavus (A. flavus) fungus was investigated with disc diffusion assay. Moreover, the biochemical changes occurring in this fungus due to exposure of different concentrations of the in-house synthesized compound are characterized by surface-enhanced Raman spectroscopy (SERS) and are illustrated in the form of SERS spectral peaks. SERS analysis yields valuable information about the probable mechanisms responsible for the antifungal effects of the Se-NHC complex. As demonstrated by the SERS spectra, this Se-NHC complex caused denaturation and conformational changes in the proteins as well as decomposition of the fungal cell membrane. The SERS spectra were analyzed using two chemometric tools such as principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA). The fungal samples' SERS spectra were differentiated using PCA, while various groups of spectra were discriminated with ultrahigh sensitivity (98%), high specificity (99.7%), accuracy (100%), and area under the receiver operating characteristic curve (87%) using PLS-DA.

Genus Equisetum L: Taxonomy, toxicology, phytochemistry and pharmacology

INTRODUCTION

The genus Equisetum (Equisetaceae) is cosmopolitan in distribution, with 41 recognized species. Several species of Equisetum are widely used in treating genitourinary and related diseases, inflammatory and rheumatic problems, hypertension, and wound healing in traditional medicine practices worldwide. This review intends to present information on the traditional uses, phytochemical components, pharmacological activities, and toxicity of Equisetum spp. and to analyze the new insights for further study.

METHODS

Relevant literature has been scanned and collected via various electronic repositories, including PubMed, Science Direct, Google Scholar, Springer Connect, and Science Online, from 1960 to 2022.

RESULTS

Sixteen Equisetum spp. were documented as widely used in traditional medicine practices by different ethnic groups throughout the world. A total of 229 chemical compounds were identified from Equisetum spp. with the major group of constituents being flavonol glycosides and flavonoids. The crude extracts and phytochemicals of Equisetum spp. exhibited significant antioxidant, antimicrobial, anti-inflammatory, antiulcerogenic, antidiabetic, hepatoprotective, and diuretic properties. A wide range of studies have also demonstrated the safety of Equisetum spp.

CONCLUSION

The reported pharmacological properties of Equisetum spp. support its use in traditional medicine, though there are gaps in understanding the traditional usage of these plants for clinical experiments. The documented information revealed that the genus is not only a great herbal remedy but also has several bioactives with the potential to be discovered as novel drugs. Detailed scientific investigation is still needed to fully understand the efficacy of this genus; hence, very few Equisetum spp. were studied in detail for phytochemical and pharmacological investigation. Moreover, its bioactives, structure-activity connection, in vivo activity, and associated mechanism of action ought to be explored further.

Synthesis, Structure-Activity Relationship, and Mechanism of a Series of Diarylhydrazide Compounds as Potential Antifungal Agents

A series of simple diarylhydrazide derivatives (45 examples) were well-designed, prepared, and screened for their antifungal activities both in vitro and in vivo. Bioassay results suggested that all designed compounds had significant activity against Alternaria brassicae (EC₅₀ = 0.30-8.35 μg/mL). Among of them, 2c, as the highest activity compound, could effectively inhibit the growth of plant pathogens Pyricularia oryza, Fusarium solani, Alternaria solani, Alternaria brassicae, and Alternaria alternate and was more potent than carbendazim and thiabendazole. 2c showed almost 100% protection at 200 μg/mL in vivo activity against A. solani in tomato. Moreover, 2c did not affect the germination of cowpea seed and the growth of normal human hepatocytes. The preliminary mechanistic exploration documented that 2c could result in the abnormal morphology and irregular structure of the cell membrane, destroy the function of mitochondria, increase the reactive oxygen species, and inhibit the proliferation of hypha cell. The above results manifested that target compound 2c could be a potential fungicidal candidate against phytopathogenic diseases for its excellent fungicidal activities.

Endophytic bacteria of Fagonia indica Burm. f revealed to harbour rich secondary antibacterial metabolites

Endophytic bacteria are the source of novel bioactive compounds, used as therapeutic agent. Molecular docking is a computational technique use frequently, to find novel drugs targets and drugs-receptors interactions. The current study was designed to isolate and identify endophytic bacteria for the extraction of bioactive compounds. Further, to characterized extracts and to explore compounds interactions with bacterial cell wall and outer membrane synthesizing proteins. Endophytes were identified using 16s rRNA amplification technique. For bioactive compounds, solvent extraction method was followed and characterized further through GC-MS analysis. To find targets and drugs-receptors interactions, molecular docking studies and biological assays were performed. The isolated endophytes belong to five different genera namely Enterobacter, Bacillus, Erwinia, Stenotrophomonas and Pantoea. In case of antibacterial assay Stenotrophomonas maltophilia extract showed significant inhibitory zones (15.11±0.11mm and 11.3±0.16) against Staphylococcus caseolyticus and Acinetobacter baumanni, with MIC 33.3 and 50μg/mL respectively. Among the characterized fifty compounds, from endophytic bacteria "antibacterial compound" N-(5-benzyl-10b-hydroxy-2-methyl-3,6-dioxooctahydro-8H-oxazolo[3,2-α] pyrrolo[2,1c] pyrazin-2-yl)-7-methyl2,3,3a,3a1,6,6a,7,8,9,10,10a,10b-dodecahydro-1H-4λ2-indolo[4,3-fg]quinoline-9-carboxamide of bacteria Stenotrophomonas maltophilia were an excellent binder with MurF ligase active site, with binding energy of -10.2 kcal/mol. Extracts of endophytic bacteria composed of various pharmacologically active ingredients such as antibacterial compounds. Molecular docking studies provide important information regarding drug-receptor interaction, thus can be used in novel drug discovery.

Treatment opportunities with Fernandoa adenophylla and recent novel approaches for natural medicinal phytochemicals as a drug delivery system

Fernandoa adenophylla (FA, Heterophragma adenophyllum) is a plant, cultivated throughout Africa and Southeast Asia. It contains potent phytochemicals such as novel naphthoquinones, their derivatives (peshwaraquinone, dilapachone, adenophyllone, indadone, and lapachol), and triterpenoids [ursolic acid (UA), β-sitosterol (BS), α-amyrin, and oleanolic acid (OA)] that have been assessed and reported to show potential pharmacological activities. The crude extract obtained from the plant has been investigated for certain pharmacological activities such as antibacterial, antifungal, anti-tubercular (TB), antihypertensive, and leishmanicidal activity. A novel drug delivery systems (NDDS) is the latest technique that combines innovative development, formulations, new technology, and methodologies for the safe delivery of pharmaceutical substances in the body. The present study reports the possible treatment opportunities of FA and recent possible novel drug delivery approaches for the natural medicinal phytochemicals.

Comparative genomic analysis reveals cellulase plays an important role in the pathogenicity of Setosphaeria turcica f. sp. zeae

Setosphaeria turcica f. sp. zeae and S. turcica f. sp. sorghi, the two formae speciales of S. turcica, cause northern leaf blight disease of corn and sorghum, respectively, and often cause serious economic losses. They have obvious physiological differentiation and show complete host specificity. Host specificity is often closely related to pathogen virulence factors, including secreted protein effectors and secondary metabolites. Genomic sequencing can provide more information for understanding the virulence mechanisms of pathogens. However, the complete genomic sequence of S. turcica f. sp. sorghi has not yet been reported, and no comparative genomic information is available for the two formae speciales. In this study, S. turcica f. sp. zeae was predicted to have fewer secreted proteins, pathogen-host interaction (PHI) genes and carbohydrate-active enzymes (CAZys) than S. turcica f. sp. sorghi. Fifteen and 20 polyketide synthase (PKS) genes were identified in S. turcica f. sp. zeae and S. turcica f. sp. sorghi, respectively, which maintained high homology. There were eight functionally annotated effector protein-encoding genes specifically in S. turcica f. sp. zeae, among which the encoding gene StCEL2 of endo-1, 4-β-D-glucanase, an important component of cellulase, was significantly up-regulated during the interaction process. Finally, gluconolactone inhibited cellulase activity and decreased infection rate and pathogenicity, which indicates that cellulase is essential for maintaining virulence. These findings demonstrate that cellulase plays an important role in the pathogenicity of S. turcica f. sp. zeae. Our results also provide a theoretical basis for future research on the molecular mechanisms underlying the pathogenicity of the two formae speciales and for identifying any associated genes.

Phytochemical Screening and In Vitro Antifungal Activity of Selected Medicinal Plants against Candida albicans and Aspergillus niger in West Shewa Zone, Ethiopia

Antimicrobial resistance to commercially available medications has become a global issue, yet there is still the possibility of developing new drugs from medicinal plants. As a result, the aims of the present study were to screen secondary metabolites and to evaluate in vitro antifungal activities of Brucea antidysenterica, Aloe vera, and Justicia schimperiana. After the plants were identified, their leaves were collected, washed, dried under the shade, pulverized, and extracted with methanol (99.8%) using the maceration technique. The presence of secondary metabolites in plant extracts was screened using various laboratory protocols. The antifungal activities of the plant extract against reference fungal strains of Candida albicans and Aspergillus niger at concentrations of 200, 100, and 50 mg/mL were assessed using the agar-well diffusion method. Ketoconazole (15 μg) was used as a positive control, while 5% dimethyl sulfoxide and/or 5% Tween 80 were used as negative controls. All tests were conducted in triplicate. Alkaloids, flavonoids, and phenols were secondary metabolites found in all plant extracts. The extract of leaves of B. antidysenterica and J. schimperiana formed a mean zone of inhibition of 15.5 ± 0.5 mm and 15.3 ± 0.58 mm, respectively, against Candida albicans at a concentration of 200 mg/mL, whereas extracts of A. vera leaves formed a 12.3 ± 0.58 mm inhibition zone only against Aspergillus niger at 200 mg/mL. In conclusion, the current study found that B. antidysenterica, A. vera, and J. schimperiana had antifungal activity. In addition, all these plants had a variety of secondary metabolites that possibly have antifungal activities. Studies on in vivo investigations and isolation of specific antifungal compounds from these medicinal plants are suggested.

Antifungal Mechanism of MTE-1, a Novel Oligosaccharide Ester, against Ustilaginoidea virens

Ustilaginoidea virens is a pathogenic fungus that causes false smut disease in rice during the flowering stage through stamen filaments. Currently, there is a need to develop safe and effective antifungal agents for the control of this disease. In our preliminary experiments, we found that MTE-1, a new trisaccharide ester, exhibits significant inhibitory activity against U. virens. Hence, the effects and inhibitory mechanism of MTE-1 in U. virens were investigated. Results showed that the MTE-1 inhibited the hyphae growth of U. virens with an IC₅₀ of 5.67 μg/mL. Similarly, MTE-1 disrupted the endomembrane system in U. virens, especially the plasma membrane, mitochondria, and lipidosome. Moreover, transcriptome and proteome analysis indicated that MTE-1 inhibited the growth of U. virens by inhibiting the synthesis of lipids, altering the primary metabolic pathways including carbohydrates and amino acid metabolism, and affecting the intracellular redox dyshomeostasis, thus leading to the disorder of active oxygen metabolism. These findings lay the foundation for the future application of MTE-1-derived agents in the management of antifungal diseases.

Antioxidant, antifungal, and aphicidal activity of the triterpenoids spinasterol and 22,23-dihydrospinasterol from leaves of Citrullus colocynthis L

Terpenoids from natural plant sources are valuable for their diverse biological activities that have important roles in the medical and agrochemical industries. In this study, we assessed the antioxidant, antifungal, and aphicidal activities of a mixture of spinasterol and 22,23-dihydrospinasterol from the leaves of Citrullus colocynthis. We used 1,1-diphenyl-2-picrylhydrazyl (DPPH) to assess antioxidant activity, and we measured antifungal activity using mycelium growth inhibition assays with three pathogenic fungi, Magnaporthe grisea, Rhizoctonia solani, and Phytophthora infestans. Aphicidal activity against adults of Myzus persicae was determined using in vitro and in vivo assays. Spinasterol and 22,23-dihydrospinasterol exhibited moderate antioxidant activity, even at lower concentrations: 19.98% at 0.78 µg mL⁻¹, 31.52% at 3.0 µg mL⁻¹, 36.61% at 12.5 µg mL⁻¹, and 49.76% at 50 µg mL⁻¹. Spinasterol and 22,23-dihydrospinasterol showed reasonable levels of fungicidal activity toward R. solani and M. grisea, with EC₅₀ values of 129.5 and 206.1 µg mL⁻¹, respectively. The positive controls boscalid and carbendazim were highly effective against all fungi except boscalid for M. grisea (EC₅₀ = 868 µg mL⁻¹) and carbendazim for P. infestans (EC₅₀ = 8721 µg mL⁻¹). Significant insecticidal activity was observed in both residual and greenhouse assays, with LC₅₀ values of 42.46, 54.86, and 180.9 µg mL⁻¹ and 32.71, 42.46, and 173.8 µg mL⁻¹ at 72, 48, and 24 h, respectively. The antioxidant activity of spinasterol and 22,23-dihydrospinasterol was strongly positively correlated with their antifungal and insecticidal activity. Spinasterol and 22,23-dihydrospinasterol therefore show good antioxidant and aphicidal activity with moderate fungicidal activity, making them suitable candidates for an alternative to synthetic agents.

Protein Extract of Tobacco Expressing Solanum torvum PP5-Encoding Gene Inhibits Verticillium dahliae Proliferation

Verticillium wilt, a soilborne disease caused by Verticillium dahliae (V. dahliae), can severely affect the yields of Solanaceae crops. In a previous study, it was observed in Solanum torvum (S. torvum) that protein phosphatase 5 (PP5) was induced by V. dahliae infection. To elucidate the function of PP5 more clearly, this study cloned an StPP5 cDNA from S. torvum by PCR. The cDNA contained an ORF of 1458 bp long encoding a putative protein of 485 amino acid residues with a predicted molecular mass of 54.63 kDa and a theoretical isoelectric point of 5.66. StPP5 protein contained a conserved PP domain and showed high similarity to other homologous members of the PP5 family from various plant species. The expression of StPP5 gene was upregulated after V. infection and reached its maximum value at 24 h in leaves. In order to clarify the role of StPP5, four transgenic tobacco plants expressing StPP5 were generated through Agrobacterium-mediated transformation and identified by PCR. In vitro culture assay showed that the growth of V. dahliae in PDA medium containing proteins extracted from the leaves of transgenic tobacco line P6 was inhibited, whose inhibition rate was 55.1%, higher than the non-transgenic control. These results indicated that StPP5 might be involved in plant defense against V. dahliae infection.

Lactic Acid Bacteria Fermentation and Endopeptidase Treatment Improve the Functional and Nutritional Features of Arthrospira platensis

This study aimed at investigating the effect of fermentation and enzymatic treatment on the degree of proteolysis of wet (WB), dried at low temperature (DB), and freeze-dried Spirulina (LB) proteins that affect the nutritional (e.g., amino acid content and profiles, and protein digestibility) and functional (e.g., antioxidant and antimicrobial activities) properties. The desiccation treatments influenced the unprocessed Spirulina characteristics because, compared with that in WB, peptides and free amino acids content was 73% lower in DB and 34% higher in LB. An integrated approach, including chromatographic and electrophoresis analyses, was used to evaluate the effect of the different bioprocessing options on protein profiles, release of peptides and amino acids, and the overall protein digestibility. Compared with the application of fermentation with the selected Lactiplantibacillus plantarum T0A10, the treatment with the endopeptidase Alcalase®, alone or combined, determined the most intense proteolysis. Moreover, the treatment with Alcalase® of LB allowed the release of potentially bioactive compounds that are able to inhibit Penicillium roqueforti growth, whereas the combination of fermentation with L. plantarum T0A10 and Alcalase® treatment increased Spirulina antioxidant properties, as determined by the scavenging activity toward ABTS radical (up to 60%) and antimicrobial activity against food pathogen Escherichia coli.

Culturable Endophytic Fungi from Glycyrrhiza inflata Distributed in Xinjiang, China with Antifungal Activity

A total of 99 endophytic fungal isolates were obtained from the roots of Glycyrrhiza inflata, which was a traditional medicinal plant mainly distributed in Xinjiang, China. Twenty-two distinct isolates were selected for further taxonomical identification by morphological traits and internal transcribed spacer (ITS) rRNA gene sequence analysis. Eleven genera were identified, among which Aspergillus, Alternaria and Fusarium were dominant. The crude extracts of 22 distinct identified fungi were successively evaluated for their antifungal activities on three rice fungal pathogens using the method of hyphal radial growth rate. Among them, the crude extract of Alternaria an-gustiovoidea Glinf007 showed the significantly mycelial growth inhibitory activity. The results demonstrated that G. inflata contained a diversity of culturable endophytic fungi, which could produce natural antimicrobial compounds that might be of great value to the agriculture and pharmaceutical industries.

Towards Advances in Medicinal Plant Antimicrobial Activity: A Review Study on Challenges and Future Perspectives

The increasing incidence of drug- resistant pathogens raises an urgent need to identify and isolate new bioactive compounds from medicinal plants using standardized modern analytical procedures. Medicinal plant-derived compounds could provide novel straightforward approaches against pathogenic bacteria. This review explores the antimicrobial activity of plant-derived components, their possible mechanisms of action, as well as their chemical potential. The focus is put on the current challenges and future perspectives surrounding medicinal plants antimicrobial activity. There are some inherent challenges regarding medicinal plant extracts and their antimicrobial efficacy. Appropriate and optimized extraction methodology plant species dependent leads to upgraded and selective extracted compounds. Antimicrobial susceptibility tests for the determination of the antimicrobial activity of plant extracts may show variations in obtained results. Moreover, there are several difficulties and problems that need to be overcome for the development of new antimicrobials from plant extracts, while efforts have been made to enhance the antimicrobial activity of chemical compounds. Research on the mechanisms of action, interplay with other substances, and the pharmacokinetic and/or pharmacodynamic profile of the medicinal plant extracts should be given high priority to characterize them as potential antimicrobial agents.

Endophytes of Brazilian Medicinal Plants With Activity Against Phytopathogens

Plant diseases caused by phytopathogens are responsible for significant crop losses worldwide. Resistance induction and biological control have been exploited in agriculture due to their enormous potential. In this study, we investigated the antimicrobial potential of endophytic fungi of leaves and petioles of medicinal plants Vochysia divergens and Stryphnodendron adstringens located in two regions of high diversity in Brazil, Pantanal, and Cerrado, respectively. We recovered 1,304 fungal isolates and based on the characteristics of the culture, were assigned to 159 phenotypes. One isolate was selected as representative of each phenotype and studied for antimicrobial activity against phytopathogens. Isolates with better biological activities were identified based on DNA sequences and phylogenetic analyzes. Among the 159 representative isolates, extracts from 12 endophytes that inhibited the mycelial growth (IG) of Colletotrichum abscissum (≥40%) were selected to expand the antimicrobial analysis. The minimum inhibitory concentrations (MIC) of the extracts were determined against citrus pathogens, C. abscissum, Phyllosticta citricarpa and Xanthomonas citri subsp. citri and the maize pathogen Fusarium graminearum. The highest activity against C. abscissum were from extracts of Pseudofusicoccum stromaticum CMRP4328 (IG: 83% and MIC: 40 μg/mL) and Diaporthe vochysiae CMRP4322 (IG: 75% and MIC: 1 μg/mL), both extracts also inhibited the development of post-bloom fruit drop symptoms in citrus flowers. The extracts were promising in inhibiting the mycelial growth of P. citricarpa and reducing the production of pycnidia in citrus leaves. Among the isolates that showed activity, the genus Diaporthe was the most common, including the new species D. cerradensis described in this study. In addition, high performance liquid chromatography, UV detection, and mass spectrometry and thin layer chromatography analyzes of extracts produced by endophytes that showed high activity, indicated D. vochysiae CMRP4322 and P. stromaticum CMRP4328 as promising strains that produce new bioactive natural products. We report here the capacity of endophytic fungi of medicinal plants to produce secondary metabolites with biological activities against phytopathogenic fungi and bacteria. The description of the new species D. cerradensis, reinforces the ability of medicinal plants found in Brazil to host a diverse group of fungi with biotechnological potential.

Plant active products and emerging interventions in water potabilisation: disinfection and multi-drug resistant pathogen treatment

Background

This review aims at establishing the emerging applications of phytobiotics in water treatment and disinfection.

Results

Statistical analysis of data obtained revealed that the use of plant product in water treatment needs more research attention. A major observation is that plants possess multifaceted components and can be sustainably developed into products for water treatment. The seed (24.53%), flower (20.75), leaf (16.98%) and fruit (11.32%) biomasses are preferred against bulb (3.77%), resin (1.89%), bark (1.89%) and tuber (1.89%). The observation suggests that novel applications of plant in water treatment need further exploration since vast and broader antimicrobial activities (63.63%) is reported than water treatment application (36.37%).

Conclusions

This review has revealed the existing knowledge gaps in exploration of plant resources for water treatment and product development. Chemical complexity of some plant extracts, lack of standardisation, slow working rate, poor water solubility, extraction and purification complexities are limitations that need to be overcome for industrial adoption of phytochemicals in water treatment. The field of phytobiotics should engage modern methodologies such as proteomics, genomics, and metabolomics to minimise challenges confronting phytobiotic standardisation. The knowledge disseminated awaits novel application for plant product development in water treatment.

Discovery of a Novel Lineage Burkholderia cepacia ST 1870 Endophytically Isolated from Medicinal Polygala paniculata Which Shows Potent In Vitro Antileishmanial and Antimicrobial Effects

In this study, we report the isolation and identification of an endophytic strain of Burkholderia cepacia (COPS strain) associated with Polygala paniculata roots. Polygala plants are rich sources of promising microbiomes, of which the literature reports several pharmacological effects, such as trypanocidal, antinociceptive, anesthetic, anxiolytics, and anticonvulsant activities. B. cepacia COPS belongs to a new sequence type (ST 1870) and harbors a genome estimated in 8.3 Mbp which exhibits the aminoglycosides and beta-lactams resistance genes aph(3′)-IIa and bla_TEM-116, respectively. Analysis performed using MLST, average nucleotide identity, and digital DNA-DNA hybridization support its species-level identification and reveals its novel housekeeping genes alleles gyrB, lepA, and phaC. The root endophyte B. cepacia COPS drew our attention from a group of 14 bacterial isolates during the primary screening for being potentially active against Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, Micrococcus luteus ATCC 9341, Escherichia coli ATCC 25922, and Candida albicans ATCC 10231 and exhibited the broad-spectrum activity against phytopathogenic fungi. In addition, COPS strain showed production of protease, lipase, and esterase in solid media, and its natural product extract showed potent inhibition against fungal plant pathogens, such as Moniliophthora perniciosa, whose antagonism index (89.32%) exceeded the positive control (74.17%), whereas Sclerotinia sclerotiorum and Ceratocystis paradoxa showed high percentages of inhibition (85.53% and 82.69%, respectively). COPS crude extract also significantly inhibited S. epidermidis ATCC 35984, E. faecium ATCC 700221 (MIC values of 32 μg/mL for both), E. faecalis ATCC 29212 (64 μg/mL), and S. aureus ATCC 25923 (128 μg/mL). We observed moderate antagonistic activity against A. baumannii ATCC 19606 and E. coli ATCC 25922 (both at 512 μg/mL), as well as potent cytotoxic effects on Leishmania infantum and Leishmania major promastigote forms with 78.25% and 57.30% inhibition. In conclusion, this study presents for the first time the isolation of an endophytic B. cepacia strain associated with P. paniculata and enough evidence that these plants may be considered a rich source of microbes for the fight against neglected diseases.

Phytochemical profile and antioxidant activity of extracts of the peruvian peppertree Schinus areira L. from Chile

The Andean tree Schinus areira L. has multiple traditional uses, from the treatment of bronchitis and rheumatic diseases to menstrual cycle regulation and wound healing. With reported hypotensive, analgesic, antitumoral and anti-inflammatory properties, it acts predominantly against diseases related to oxidative stress. This study focuses on the antioxidant activity and phytochemical profile of the extracts of Schinus areira L.

Serial extraction of the fruits was performed both by maceration and by Soxhlet. Total phenols and flavonoids were measured using the Folin-Ciocalteu method and AlCl₃, respectively. In vitro antioxidant activity was determined by FRAP and DPPH.

Results were similar for both extraction methods. Primary metabolites detected included carbohydrates, proteins and amino acids; secondary metabolites included tannins, flavonoids, saponins, steroids and triterpenes. Antioxidant activity was confirmed for ethyl acetate, methanolic and aqueous extracts. The methanolic extract had both the highest polyphenol content (>195 mg GAE/ g dry weight) and the highest antioxidant activity [EC₅₀ > 476 μg/mL; >273 mg AA/g dry weight (DPPH); >301 mg AA/ g dry weight (FRAP)]. The extract does not produce macrophage cytotoxicity in RAW 264.7, which is indicated by an average cytotoxicity of 2% over 24 h.

Our study serves as a starting point for future research on the pharmacological properties of Schinus areira L.

Extension of the Shelf-Life of Fresh Pasta Using Chickpea Flour Fermented with Selected Lactic Acid Bacteria

Fresh pasta is subjected to rapid spoilage, mainly due to the metabolic activity of bacteria, yeasts, and especially molds, which negatively affect the sensorial characteristics and the safety of the product. In this work, chickpea flour was fermented with selected lactic acid bacteria, characterized in terms of the antifungal activity, and used to fortify fresh semolina pasta. Pasta was characterized and subjected to a long period of storage after being artificially inoculated with Penicillium roqueforti. Conventional fresh semolina pasta, produced with or without calcium propionate addition, was used as a reference. The water/salt-soluble extract from chickpea sourdough exhibited antifungal activity towards a large spectrum of molds. Its purification led to the identification of ten potentially active peptides. Besides the high content of dietary fibers (4.37%) and proteins (11.20%), nutritional improvements, such as the decrease of the antinutritional factors concentration and the starch hydrolysis index (25% lower than the control) and the increase of the protein digestibility (36% higher than the control), were achieved in fresh pasta fortified with the chickpea sourdough. Inhibition of the indicator mold growth during a 40-day storage period was more effective than in pasta added to calcium propionate.

Antifungal and Phytotoxic Activities of Essential Oils: In Vitro Assays and Their Potential Use in Crop Protection

(1) Background: The use of natural products based on essential oils (EO) is nowadays arousing great interest as an alternative method to control plant pathogens and weeds. However, EO possess low bioavailability and are highly volatile, and their encapsulation in hydroxypropyl-ß-cyclodextrin (HP-β-CD) could be a means to enhance their stability and maintain their bioactivity. Thus, the current study aims at investigating, in the presence and the absence of HP-β-CD, the antifungal and phytotoxic activities of nine EO, distilled from plant species belonging to Alliaceae, Apiaceae, and Cupressaceae families, with considerations for their chemical composition. (2) Methods: EO antifungal activity was assessed by direct contact and volatility assays against Fusarium culmorum, a major phytopathogenic fungi, while phytotoxic effects were evaluated against lettuce (Lactuca sativa L.) and rye-grass (Lolium perenne L.), by seedling’s emergence and growth assays. (3) Results: These EO inhibit fungal growth in both direct contact and volatility assays, with half-maximal inhibitory concentrations (IC50) ranging from 0.01 to 4.2 g L−1, and from 0.08 up to 25.6 g L−1, respectively. Concerning phytotoxicity, these EO have shown great potential in inhibiting lettuce (IC50 ranging from 0.0008 up to 0.3 g L−1) and rye-grass (IC50 ranging from 0.01 to 0.8 g L−1) seedlings’ emergence and growth. However, the EO encapsulation in HP-β-CD has not shown a significant improvement in EO biological properties in our experimental conditions. (4) Conclusion: All tested EO present antifungal and phytotoxic activities, with diverse efficacy regarding their chemical composition, whilst no increase of their biological effects was observed with HP-β-CD.

Leishmanicidal, Antifungal, and Cytotoxic Activity of Triterpenoid Glycosides Isolated from the Sea Cucumber Neothyone Gibbosa

Neothyosides A - C, isolated from the body walls of the sea cucumber Neothyone gibbosa Deichmann, and a partially purified mixture of these saponins, were tested in vitro against promastigotes of two strains of Leishmania mexicana and a panel of several fungi using the broth microdilution technique. In addition, the cytotoxicity of these saponins was tested against Artemia salina. The IR, 1H and 13C NMR spectroscopic and FAB MS data of neothyoside C revealed that its structure was identical to that of pervicoside B, isolated from another sea cucumber species, Holothuria pervicax. Neothyoside C was the most active antiparasitic compound, inhibiting 100% of the promastigotes at 5 and 10 μg/mL of both L. mexicana strains. The mixture of saponins and pure neothyoside C showed the best activity against Aspergillus niger strains with MIC values between 15.6 μg/mL and 16.7 μg/mL for the mixture, and 4.65 μg/mL and 7.8 μg/mL for neothyoside C. Assays for cytotoxicity using Artemia salina showed that neothyosides A and C caused 50% brine-shrimp deaths at 130 and 63 μg/mL with this cytotoxicity 4 to 6 times greater than the concentration at which these compounds produce an antimicrobial effect. This is the first report describing the antileishmanial, antifungal, and cytotoxic activity of N. gibbosa saponins.

Novel solid-state fermentation of bee-collected pollen emulating the natural fermentation process of bee bread

Structure of lactic acid bacteria biota in ivy flowers, fresh bee-collected pollen (BCP), hive-stored bee bread, and honeybee gastrointestinal tract was investigated. Although a large microbial diversity characterized flowers and fresh BCP, most of lactic acid bacteria species disappeared throughout the bee bread maturation, giving way to Lactobacillus kunkeei and Fructobacillus fructosus to dominate long stored bee bread and honeybee crop. Adaptation of lactic acid bacteria was mainly related to species-specific, and, more in deep, to strain-specific features. Bee bread preservation seemed related to bacteria metabolites, produced especially by some L. kunkeei strains, which likely gave to lactic acid bacteria the capacity to outcompete other microbial groups. A protocol to ferment BCP was successfully set up, which included the mixed inoculum of selected L. kunkeei strains and Hanseniaspora uvarum AN8Y27B, almost emulating the spontaneous fermentation of bee bread. The strict relationship between lactic acid bacteria and yeasts during bee bread maturation was highlighted. The use of the selected starters increased the digestibility and bioavailability of nutrients and bioactive compounds naturally occurring in BCP. Our biotechnological protocol ensured a product microbiologically stable and safe. Conversely, raw BCP was more exposed to the uncontrolled growth of yeasts, moulds, and other bacterial groups.

NADES-mediated folk plant extracts as novel antifungal agents against Candida albicans

Candida albicans is an opportunistic pathogenic yeast commonly found in mouth, gastrointestinal tract and vagina. Under certain conditions, it causes skin, mucosal and systemic infections. With growing concern over the emergence of resistant strains to conventional antifungals, the development of novel antifungal agents for the management of this pathogen is an urgent need. In the present work, novel bioextracts from folk medicinal plants were directly used as active ingredient in a topical formulation for dermal candidiasis. With the aim to replace hazardous traditional reagents, a natural solvent composed by lactic acid: glucose: water (LGH) was used as vehicle for bioactive compound extraction. Furthermore, phenolic and alkaloid composition were determined by HPLC and their individual antifungal effect was evaluated. LGH extracts of Larrea spices demonstrate a significant antimicrobial activity against C. albicans being higher than their individual bioactive constituents. Notably, the mixture of Larrea cuneifolia and L divaricata extracts in topical formulations reveal a synergistic antifungal effect highlighting their potential for candidiasis treatment.

Chemical composition and enzyme inhibition of Phytolacca dioica L. seeds extracts

Phytolacca, which belongs to the family of Phytolaccaceae, are known for their use in popular medicine. Bioactivity of five extracts from Phytolacca dioica seeds were evaluated in four bioassays. A selected group of compounds from the extract that displayed the best bioactivity was analysed. The ethyl acetate extract (EAE) possessed the highest content of phenolics, the highest inhibitory activity on the tyrosinase and xanthine oxidase enzymes and showed a high antioxidant activity. HPLC-DAD-MS was employed to identify the phenolics profile of the most active one (EAE). HSCCC analysis of the EAE led to the isolation of phytolaccoside B and a mixture of 4 isomers, isoamericanol B1, B2, C1 and C2. These isoamericanol isomers presented activity against tyrosinase and xanthine oxidase. Our results revealed for the first time an interesting biological activity of the extract and isolated compounds from P. dioica seeds, which could be considered as a source of bioactive molecules.

Bioprospecting and Structure of Fungal Endophyte Communities Found in the Brazilian Biomes, Pantanal, and Cerrado

Medicinal plants have been recognized as hosts of high diverse endophytic microorganisms, including fungi that produce secondary metabolites with biological activity. Two biomes in Brazil, Pantanal (wetland), and Cerrado (savannah), are known as biodiversity hotspots, and despite their importance as a reservoir for several species, knowledge about the fungal biodiversity in these biomes is very limited. Fungal endophytic communities associated with leaves and petioles of the medicinal plants Vochysia divergens (from Pantanal) and Stryphnodendron adstringens (from Cerrado) were analyzed and studied for their antimicrobial activity against human and plant pathogens. A total of 1,146 isolates of endophytic fungi were obtained from plants collected in January and June of 2016 and grouped into 124 morphotypes. One isolate of each morphotype was identified by sequencing of internal transcribed spacer (ITS) region of the rDNA gene, which revealed the presence of 24 genera, including 3 possible new genera, and 48 taxa. Differences in the endophytic community according to the biomes were observed concerning the analyzed morphotypes. However, when we analyzed the diversity of genera and richness, they were similar for both plants, with Diaporthe, Phyllosticta, and Neofusicoccum as dominant genera. In addition, the community composition of V. divergens differs according to the analyzed plant tissues (petiole and leaf). These data suggested that both, the plant species and plant tissues play a role in the composition of endophytic community. As regards the biotechnological potential, 5 isolates showed activity against the phytopathogens Phyllosticta citricarpa, Colletotrichum abscissum, and Fusarium verticilioides, and 8 isolates showed high activity against clinical pathogens and were selected for the production of crude extract in different culture media. Extract from cultivation of Diaporthe sp. LGMF1548 and LGMF1583 and Neofusicoccum brasiliense LGMF1535 showed activity against methicillin-resistant Staphylococcus aureus, Klebssiella pneumonia, and Candida albicans. In addition, extracts of Diaporthe cf. heveae LGMF1631 inhibited 90% of the mycelial growth of the P. citricarpa and 70% of C. abscissum and may represent an alternative to be used in the biological control of these phytopathogens. Future research will focus on the chemical characterization and structural elucidation of these bioactive compounds.

Argentinean Larrea Dry Extracts with Potential Use in Vaginal Candidiasis

Larrea divaricata (Ld), Larrea cuneifolia (Lc) and Larrea nitida (Ln) are shrubs occurring in Northwestern Argentina used in traditional medicine to treat fungal and bacterial infections and as anti-inflammatory. Antibacterial and antifungal activity of several Larrea species has been reported. However, their potential use in vaginal infections has been so far not assessed. The aim of this work was to determine the botanical difference between Larrea species, the chemical composition and the activity of Larrea dry extracts (DE) on Candida species isolated from vaginal infections and to assess their potential as antioxidant agents because infections are usually associated with oxidative processes. The main botanical difference between Larrea species resides in the morphology and shape of leaf, leaflets and stipules, presence or absence of mucron and rachis, percentage of coalescence of the leaflets. The position and abundance of the sclerenchymatic tissue at the mind vein and petiole transection allows the differentiation of the three species. The profile of phenolic compounds in the Larrea DE was determined. HPLC-ESI-MS/MS analysis of DE allowed the identification of 2 flavonoids and 10 lignans. Trihydroxy-6,7′cyclolignan was found only in L. divaricata and dihydroxy-methoxy-epoxylignan in L. cuneifolia and L. nitida, nordihydroguaiaretic acid (NDGA) was found in the three species. All extracts showed antioxidant capacity. The DE showed to be effective against Candida albicans and non-albicans strains. According to our results, the local vaginal use of Larrea DE in the concentration range of MIC values for Candida species does not affect the Lactobacillus normal vaginal microbiota. This work adds evidence to the potential use of Larrea DE as phytomedicine in vulvovaginal candidiasis with multiple effects, including antifungal and antioxidant activity.

Polarity directed optimization of phytochemical and in vitro biological potential of an indigenous folklore: Quercus dilatata Lindl. ex Royle

BACKGROUND

Plants have served either as a natural templates for the development of new chemicals or a phytomedicine since antiquity. Therefore, the present study was aimed to appraise the polarity directed antioxidant, cytotoxic, protein kinase inhibitory, antileishmanial and glucose modulatory attributes of a Himalayan medicinal plant- Quercus dilatata.

METHODS

Total phenolic and flavonoid contents were determined colorimetrically and various polyphenols were identified by RP-HPLC analysis. Brine shrimp lethality, SRB and MTT assays were employed to test cytotoxicity against Artemia salina and human cancer cell lines respectively. Antileishmanial activity was determined using standard MTT protocol. Glucose modulation was assessed by α-amylase inhibition assay while disc diffusion assay was used to establish protein kinase inhibitory and antifungal spectrum.

RESULTS

Among 14 extracts of aerial parts, distilled water-acetone extract demonstrated maximum extract recovery (10.52% w/w), phenolic content (21.37 ± 0.21 μg GAE/mg dry weight (DW)), total antioxidant capacity (4.81 ± 0.98 μg AAE/mg DW) and reducing power potential (20.03 ± 2.4 μg/mg DW). On the other hand, Distilled water extract proficiently extracted flavonoid content (4.78 ± 0.51 μg QE/mg DW). RP-HPLC analysis revealed the presence of significant amounts of phenolic metabolites (0.049 to 15.336 μg/mg extract) including, pyrocatechol, gallic acid, catechin, chlorogenic acid, p-coumaric acid, ferulic acid and quercetin. Highest free radical scavenging capacity was found in Methanol-Ethyl acetate extract (IC₅₀ 8.1 ± 0.5 μg/ml). In the brine shrimp toxicity assay, most of the tested extracts (57%) showed high cytotoxicity. Among these, Chloroform-Methanol extract had highest cytotoxicity against THP-1 cell line (IC₅₀ 3.88 ± 0.53 μg/ml). About 50% of the extracts were found to be moderately antiproliferative against Hep G2 cell line. Methanol extract exhibited considerable protein kinase inhibitory activity against Streptomyces 85E strain (28 ± 0.35 mm bald phenotype at 100 μg/disc; MIC = 12.5 μg/ disc) while, Chloroform extract displayed maximum antidiabetic activity (α-amylase inhibition of 21.61 ± 1.53% at 200 μg/ml concentration). The highest antileishmanial potential was found in Ethyl acetate-Acetone extract (12.91 ± 0.02% at 100 μg/ml concentration), while, Q. dilatata extracts also showed a moderate antifungal activity.

CONCLUSION

This study proposes that multiple-solvent system is a crucial variable to elucidate pharmacological potential of Q. dilatata and the results of the present findings prospects its potential as a resource for the discovery of novel anticancer, antidiabetic, antileishmanial and antioxidant agents.

Antimicrobial and antioxidant activities of a new metabolite from Quercus incana

Phytochemical investigations of Quercus incana led to the isolation of a new catechin derivative quercuschin (1), along with six known compounds: quercetin (2), methyl gallate (3), gallic acid (4), betulinic acid (5), (Z)-9-octadecenoic acid methyl ester (6) and β-sitosterol glucoside (7) from the ethyl acetate fraction of methanolic extract of the bark. Compound 1 was screened for its antibacterial, antifungal and antioxidant potential. Antibacterial and antifungal activities of the compound were tested against different bacterial and fungal strains, employing the agar well diffusion methods. The antibacterial activity was the highest against Streptococcus pyogenes with 80.0% inhibition, while the antifungal activity of the compound was the highest against Candida glabrata with 80.5% inhibition. The results of the antioxidant activity indicated that the compound exhibited antioxidant activity comparable to that of standard, butylated hydroxyanisole (51.2 μg/10 μl versus 45.9 μg/10 μl).