Remarkable Antifungal Effect Research Articles

Chemical Composition and Biocontrol Activity of Different Essential Oils against Soil-Borne Fungal Pathogens.

In this study, the efficacy of the essential oil of Mentha longifolia, Achillea arabica and Artemisia absinthium plants were evaluated against important soil-borne fungal pathogens as Verticillium dahliae, Rhizoctonia solani, and Fusarium oxysporum. Essential oils were obtained from plants by hydrodistillation method and the chemical components of essential oils were determined by analyzing by gas chromatography-mass spectrometry. The main components found as piperitone oxide (13.61%), piperitenone oxide (15.55%), pulegone (12.47%), 1-menthone (5.75%), and camphor (5.75%) in M. longifolia, á-selinene 13.38%, camphor 13.34%, L-4-terpineneol 8.40%, (-)-á-Elemene 7.01%, 1,8-cineole 4.71%, and (-)-spathulenol 3.84% in A. arabica, and á-thujone (34.64%), 1,8-cineole (19.54%), pulegone (7.86%), camphene (5.31%), sabinene (4.86%), and germacrene-d (3.67%) in A. absinthium. The antifungal activities of the oils were investigated 0.05, 0.1, 0.25, 0.5, 1.00, and 2.00 μl/ml concentrations with the contact effect method. M. longifolia oil (1.00 and 2.00 μl/ml) has displayed remarkable antifungal effect and provided 100% inhibition on mycelial growth of V. dahliae, R. solani and F. oxysporum. The results obtained from this study may contribute to the development of new alternative and safe methods against soil-borne fungal pathogens.

Isochlorogenic Acid Glucosides from the Arabian Medicinal Plant Artemisia sieberi and Their Antimicrobial Activities.

A phytochemical investigation of the stems of the Arabian plant Artemisia sieberi afforded three new isochlorogenic acid derivatives, namely isochlorogenic acid A-3'-O-β-glucopyranoside (1), isochlorogenic acid A-3'-O-β-glucopyranoside methyl ester (2), and isochlorogenic acid C-3'-O-β-glucopyranoside (3), obtained along with thirteen known secondary metabolites belonging to distinct structural classes. The structures of the new metabolites were elucidated by modern spectroscopic techniues based on high-resolution mass spectrometry (HR-ESIMS) and 1D/2D nuclear magnetic resonance (NMR). All isolated compounds were tested for their potential antimicrobial activity against four different bacterial strains (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa), in addition to a fungal strain (Candida tropicalis), The results were expressed as the diameter of the clear zone (in millimetres) around each well. Compounds 1 and 3 (isochlorogenic acid A-3'-O-β-glucopyranoside and isochlorogenic acid C-3'-O-β-glucopyranoside, respectively) displayed remarkable antifungal effect and potent antibacterial activities against B. subtilis and S. aureus, respectively. 3α,4α-10β-trihydroxy-8α-acetyloxyguaian-12,6α-olide (6) and angelicoidenol 2-O-β-d-glucopyranoside (9) emerged as interesting dual antibacterial (selective on P. aeruginosa)/antifungal agents.

Evaluation of Curcumin Nanoparticles against Rabbit Skin Infection

Curcumin is a polyphenolic compound with multiple beneficial effects in human health. It has shown a remarkable anti-inflammatory, antibacterial, antifungal, anticancer, and antioxidant effects. The limitations of curcumin are primarily in its bioavailability. Curcumin nanoparticles is suggested to reduce the limitation of bulk curcumin and probably enhance its desired effect. Curcumin was turned into nanoparticles by using simple wet-milling method. The characterization of curcumin nanoparticles indicated the presence of curcumin in size less than 100 nm. The effect of both curcumin and curcumin nanoparticles on wound healing was investigated in rabbits, in paraffin wax. Rabbits whom under curcumin and curcumin nanoparticles have shown faster healing from day 5 compared to control rabbits whom showed a proximate advancement after day 7. On day 14, rabbits whom treated with bulk and nanosized curcumin have shown a perfect healing with no sign of infection. Furthermore, both bulk and nanosized curcumin have shown a comparable antioxidant effect with ascorbic acid. Furthermore, curcumin nanoparticles were exhibited a slightly powerful antioxidant effect compared to curcumin.

Chelerythrine Inhibits Stemness of Cancer Stem-Like Cells of Osteosarcoma and PI3K/AKT/mTOR Signal.

Chelerythrine (CHE) is widely found in many herbs and is the main alkaloid constituent of Toddalia asiatica (L.) LAM. It has been proved to exert remarkable antitumor, antifungal, anti-inflammatory, and antiparasitic effects. In osteosarcoma, CHE is reported to inhibit proliferation and promote apoptosis. However, the effect of CHE on cancer stem-like cells (CSCs), which contribute to metastasis and recurrence in osteosarcoma, is still largely unknown. In this study, we investigated the effects of CHE on the stemness and malignant behaviors of CSCs derived from osteosarcoma cells. CSCs were enriched by culturing in serum-free medium. The effects of CHE on stemness were measured by detecting stemness factors and sphere formation ability. The effects of CHE on chemosensitivity to doxorubicin and MTX were measured by Annexin V-FITC/PI double staining. The effects of CHE on CSC malignancy were measured by performing CCK-8, colony formation, tumor formation in soft agar, migration, and invasion assays. We first enriched CSCs from osteosarcoma cells, which were characterized by upregulated stemness markers, including Oct4, Nanog, and Nestin. The addition of CHE clearly decreased malignant behaviors, including colony formation, tumor formation in soft agar, migration, and invasion. CHE also inhibited stemness and thus induced the failure of sphere formation. Moreover, CHE promoted apoptosis induced by chemo agents, including doxorubicin (DOX) and methotrexate (MTX). After CHE treatment, the protein expression of MMP-2/9 was significantly decreased, potentially inhibiting invasion. CHE also exhibited an inhibitory effect on the phosphorylation of PI3K, AKT, and mTOR, which is an upstream regulatory signaling pathway of MMP-2/9. In summary, CSCs derived from U2OS and MG-63 cells, CHE could inhibit the stemness and malignant behaviors of CSCs potentially by inhibiting the PI3K/AKT/mTOR signaling pathway.

Development of fluorinated nicotinonitriles and fused candidates as antimicrobial, antibiofilm, and enzyme inhibitors.

The antimicrobial assessments of two new series of nicotinonitriles and pyrido[2,3-d]pyrimidines were performed using amoxicillin and nystatin as reference standards. Outstanding antifungal activities were achieved by some target compounds; for instance, compounds 7 and 9 displayed a minimal inhibitory concentration (MIC) value of 1.95 µg/ml toward Candida albicans, compound 11 showed a potent anti-Rhizopus effect (MIC 1.95 µg/ml) and compound 14 elicited remarkable antifungal effects against both Aspergillis niger and C. albicans (MIC 1.95 µg/ml). However, pyrido[2,3-d]pyrimidines 12, 14, and 16 showed moderate antibacterial activities against some gram-negative bacteria. The antibiofilm results of these compounds against resistant strains of Proteus mirabilis were better than those of Pseudomonas aeruginosa. Docking studies of these hits at the DNA gyrase active site revealed affinity and docking scores comparable to that of the reference standards. Gyrase-inhibitory activities revealed that 14 (IC50 = 0.31 µM) is the most potent hit as DNA gyrase A inhibitor; it exhibited 1.66-fold the activity of ciprofloxacin (IC50 = 0.50 µM) and it was a 44.3 times more potent gyrase B inhibitor (IC50 = 0.04 µM) than novobiocin (IC50 = 1.77 µM). Regarding its antifungal activity, it displayed 0.78% of the fluconazole activity as a 14α-demethylase inhibitor. The cytotoxicity of 12, 14, and 16 on human diploid lung fibroblasts (WI38 cells) ensured their safety. Moreover, they are orally bioavailable with no permeation of the blood-brain barrier.

A pH-responsive MOF for site-specific delivery of fungicide to control citrus disease of Botrytis cinerea

The pH-responsive controlled release of Boscalid with low toxicity. • 18% Boscalid has been loaded in ZIF-67 nanocarriers with large pore size. • Release of Boscalid@ZIF-67 can be triggered in acid condition. • Boscalid@ZIF-67 exhibits remarkable antifungal effect over Botrytis cinerea . Pesticides have been always restricted by poor efficacy and inacceptable toxicity. In this work, a pH-sensitive controlled-release nano-capsule of fungicide, Boscalid@ZIF-67 (ZIF is a subclass of MOF), was prepared based on metal–organic framework (MOF) for higher antifungal effect and low bio-toxicity. The Boscalid@ZIF-67 was formed by physical adsorption method and it possesses uniform size and dodecahedral shape. The loading ratio is as high as 18%. In addition, the release of fungicide Boscalid showed pH sensitive response due to the weak acidic group in the MOF structure, in which the rate of release was more rapid under acid condition (＜7). Cumulative release rate release was higher about 25% and 38% adjusted from 7 to 3.5 and from 7 to 5.5 on the 6th day than that under neutral condition. At the early stage of infecting the host plant, Botrytis cinerea will produce more acidic substances such as oxalic acid, which are conducive to Boscalid@ZIF-67 disintegration for rapid release of Boscalid. Meanwhile, the antifungal effect of Boscalid@ZIF-67 was 4–6 times more of that commercially available product on Botrytis cinerea , while the bio-toxicity under the same condition is much lower than that of latter. Thus, this work not only proves that Boscalid@ZIF-67 could be used as nanoparticles platform for smart control over Botrytis cinerea , but also has great potential to improve traditional modalities by addressing the crop diseases in economic and ecological manner.

Synthesis and in vitro antifungal activity of new Michael-type amino derivatives of xanthatin, a natural sesquiterpene lactone from Xanthium strumarium L.

Structural optimization using plant secondary metabolites as templates is one of the important approach to discover pesticide molecules with novel skeletons. Xanthatin, a natural sesquiterpene lactone isolated from the Xanthium plants (Family: Compositae), exhibits important biological properties. In this work, a series of Michael-type amino derivatives were prepared from xanthatin and their structures were characterized by 1H NMR, 13C NMR and HR-MS, and their antifungal activities against several phytopathogenic fungi were evaluated according to the spore germination method and mycelium growth rate method in vitro. The results illustrated that compounds 2g (IC50 = 78.91 µg/mL) and 2o (IC50 = 64.51 µg/mL) exhibited more promising inhibition activity against spores of F. solani than precursor xanthatin, compounds 2g, 2l, and 2r exhibited remarkable antifungal effect on C. mandshurica with the average inhibition rates (AIRs) >90%, whereas the AIR of xanthatin was only 59.34%. Meanwhile, the preliminary structure–activity relationships suggested that the amino containing 2-methoxyethyl or 4-chlorophenylmethyl group appended in the C-13 position of xanthatin could yield potential compounds against fungal spores, and the exocyclic double bond of xanthatin is essential to maintain its mycelial growth inhibitory activity. Therefore, the aforementioned findings indicate that partial xanthatin amino-derivatives could be considered for further exploration as the potential lead structures toward development of the new environmentally friendly fungicidal candidates for sustainable crop protection.

Anti-fungal activity and preliminary active components separation from ethanol extracts in Saffron (Crocus sativus L.) lateral buds

Saffron (Crocus sativus L.) is renowned for the active compounds contained in its stigmas, which are used in traditional medicine and as a spice. However, although the stigmas are well above the average yield, the lateral buds of saffron are usually discarded in saffron culturing. In order to expand saffron resource utilization, this study assessed the anti-fungal activities of saffron lateral bud ethanol extracts on six common food-borne pathogenic fungi, as well as investigated the stability of these activities under various heat and pH conditions. Furthermore, the active anti-fungal components of ethyl acetate phase were preliminarily separated by silica gel column chromatography technology and its major chemical constituents were investigated by HPLC-MS/MS. Results revealed that the ethyl acetate phase of saffron lateral bud ethanol extracts elicited a remarkable anti-fungal effect against the tested fungi, especially Aspergillus niger (83.47 %) and Trichoderma viride (79.93 %). Moreover, these inhibitory effects were stable in neutral and acidic pH ranges at temperatures < 100 °C. The ethyl acetate phase can further be separated into eight fractions by silica gel column chromatography, of which fraction 6 (F6) had the strongest anti-fungal effect by anti-fungal activity evaluation in vitro. HPLC-MS/MS analysis showed that the major compounds of F6 mostly belonged to polyphenols. To summarize, these findings demonstrated that saffron lateral buds are a potentially efficient and affordable source of natural preservatives for use in food.

The Genus Haplophyllum Juss.: Phytochemistry and Bioactivities-A Review.

Herein, a comprehensive review is given focusing on the chemical profiles of the essential oils (EOs), non-volatile compounds, ethnobotany, and biological activities of different Haplophyllum (Rutaceae family) species. To gather the relevant data, all the scientific databases, including Scopus, ISI-WOS (Institute of Scientific Information-Web of Science), and PubMed and highly esteemed publishers such as Elsevier, Springer, Taylor and Francis, etc., were systematically retrieved and reviewed. A wide array of valuable groups of natural compounds, e.g., terpenoids, coumarins, alkaloids, lignans, flavonoids, and organic acids have been isolated and subsequently characterized in different organic extracts of a number of Haplophyllum species. In addition, some remarkable antimicrobial, antifungal, anti-inflammatory, anticancer, cytotoxic, antileishmanial, and antialgal effects as well as promising remedial therapeutic properties have been well-documented for some species of the genus Haplophyllum.

Antimicrobial activities evaluation and phytochemical screening of some selected medicinal plants: A possible alternative in the treatment of multidrug-resistant microbes.

BackgroundFour out of five individuals rely on traditional medicine for their primary healthcare needs. Medicinal plants are endowed with diverse bioactive compounds to treat multidrug-resistant (MDR) microbes. So far, a less thorough examination has been made in this regard. This study aimed to evaluate antimicrobial activity and phytochemical screening of selected medicinal plants against MDR microbes.MethodsIn vitro experimental study was carried out to evaluate antimicrobial effects and phytochemical screening of Rumex abyssinicus, Cucumis pustulatus, Discopodium penninervium, Lippia adoensis, Euphorbia depauperata, Cirsium englerianum, and Polysphaeria aethiopica against MDR bacteria and fungi. Aqueous and 80% methanolic extraction methods were employed for extraction. The susceptibility test, minimum inhibitory concentration, and minimum bactericidal or fungicidal concentration were measured using disc diffusion or broth micro-dilution as per the CLSI protocols.ResultThe 80% methanolic extraction method was a preferred method to aqueous. The phytochemical constituents identified were alkaloids, flavonoids, saponins, phenolic, tannins, terpenoidss, and cardiac glycosides. The hydroalcoholic extract demonstrated an appreciable antimicrobial role against MDR microbes with an MIC value of 1.0–128.0μg/ml and 11-29mm inhibition zone (IZ) in diameter. Extracts obtained from C. englerianum and E. depauperata showed a significant IZ ranged of 26-29mm on MRSA and Streptococcus pyogenes. MDR E. coli and K. pneumoniae showed 12-25mm and 23-28mm IZ in diameter, respectively. T. mentagraphytes was susceptible to all tested extracts. Moreover, S. pyogenes and K. pneumoniae were found the most susceptible bacteria to C. englerianum. Cirsium englerianum, L. adoensis, D. penninervium, and R. abyssinicus demonstrated remarkable antifungal effect against C. albicans and T. mentagrophytes, while R. abyssinicus showed the leading antifungal effect with 32 to 64μg/ml MIC values.ConclusionThe plant extracts have shown appreciable antimicrobial activities comparable to the currently prescribed modern drugs tested. Accordingly, further studies on clinical efficacy trial, safety, toxicity and affordability analyses have to be instigated promptly, so as to head to the final step to synthesize precursor molecules for new effective antimicrobials.

Mn3O4 nanoparticles bearing 5-amino-2-mercapto benzimidazole moiety as antibacterial and antifungal agents

The antibacterial and antifungal effects of non-functionalized and surface-functionalized Mn3O4 nanoparticles were comparatively analyzed to reason out the potential changes in antimicrobial activities due to functionalization with 5-amino-2-mercapto benzimidazole (AMB) molecule. The surface functionalization of Mn3O4 nanoparticles with AMB molecule was confirmed by the XRD result, which shows the shift in 2θ values with noticeable peaks. The surface morphology and functionalization of Mn3O4 nanoparticles were additionally confirmed by HR-SEM and EDAX studies. Antimicrobial activities were investigated by an agar-well-diffusion method using the bacteria Staphylococcus aureus and Pseudomonas aeruginosa and fungi Aspergillus niger. The functionalized Mn3O4 nanoparticles possess remarkable antibacterial and antifungal effect than the non-functionalized Mn3O4 nanoparticles and AMB molecule. The coating of low energy surface layer over metal oxide nanoparticles such as Mn3O4 offers an active surface toward both transfer of electron and the adsorption or desorption of water, inorganic ions, and other molecules, which leads to the increased antimicrobial activity of f-Mn3O4 nanoparticles. Communicated by Ramaswamy H. Sarma

Insight into the phase inversion of a turmeric oil nanoemulsion in antifungal process

SummaryAntimicrobial essential oil nanoemulsions have been wildly applied in plant sterilisation. Here, a turmeric oil (TO) oil‐in‐water (O/W) nanoemulsion was developed to understand the antifungal mechanism between TO and Podosphaera xanthii (P. xanthii), simulating a moisture evaporation after spraying TO nanoemulsion on plant leaves. Dynamic light scattering (DLS) and cryogenic transmission electron microscopy (cryo‐TEM) suggested the average hydrodynamic diameter of spherical TO nanoemulsion droplets was 150.2 nm with polydispersity index (PDI) of 0.17, which suggested no significant change after storing at 54 °C for 2 weeks. Atomic force microscope (AFM) as well as conductivity and viscosity demonstrated the phase inversion of droplets from O/W to water‐in‐oil (W/O) types during moisture evaporation is a primary mechanism to reveal the antifungal TO on cucumber leaves. Finally, the antifungal capacity of TO nanoemulsion was evaluated on living cucumber plants and demonstrated a remarkable antifungal effect on inhibiting the growth of P. xanthii.

Ocotea glomerata (Nees) Mez Extract and Fractions: Chemical Characterization, Anti-Candida Activity and Related Mechanism of Action.

Background: Opportunistic fungal infections are increasingly common, with Candida albicans being the most common etiological agent; however, in recent years, episodes of candidiasis caused by non-albicans Candida species have emerged. Plants belonging to the Lauraceae family have shown remarkable antifungal effects. This study assessed the anti-Candida activity of Ocotea glomerata extracts and fractions, time of death and the synergistic effects with conventional antifungals. The possible mechanism of action was also addressed. Methods: Minimal inhibitory concentrations (MIC) were determined by broth microdilution technique, and the mechanism of action was assessed by ergosterol, sorbitol, cell viability, reactive oxygen species (ROS) generation and phosphatidylserine externalization tests. Results: All the tested extracts evidenced antifungal activity, but the methanol extract was revealed to be the most effective (MIC = 3.12 μg/mL) on C. krusei. The combination of methanol extract with ketoconazole and fluconazole revealed a synergistic effect for C. krusei and C. albicans, respectively. Fractions 1 and 5 obtained from the methanol extract had fungicidal activity, mainly against C. krusei. Methanol extract did not reveal effects by ergosterol and sorbitol assays; however, it led to an increase in intracellular ROS levels, decreased cell viability, and consequently, cell death. Conclusion: O. glomerata methanol extract may be viewed as a rich source of biomolecules with antifungal activity against Candida spp.

Fungal Quorum-Sensing Molecules: A Review of Their Antifungal Effect against Candida Biofilms.

The number of effective therapeutic strategies against biofilms is limited; development of novel therapies is urgently needed to treat a variety of biofilm-associated infections. Quorum sensing is a special form of microbial cell-to-cell communication that is responsible for the release of numerous extracellular molecules, whose concentration is proportional with cell density. Candida-secreted quorum-sensing molecules (i.e., farnesol and tyrosol) have a pivotal role in morphogenesis, biofilm formation, and virulence. Farnesol can mediate the hyphae-to-yeast transition, while tyrosol has the opposite effect of inducing transition from the yeast to hyphal form. A number of questions regarding Candida quorum sensing remain to be addressed; nevertheless, the literature shows that farnesol and tyrosol possess remarkable antifungal and anti-biofilm effect at supraphysiological concentration. Furthermore, previous in vitro and in vivo data suggest that they may have a potent adjuvant effect in combination with certain traditional antifungal agents. This review discusses the most promising farnesol- and tyrosol-based in vitro and in vivo results, which may be a foundation for future development of novel therapeutic strategies to combat Candida biofilms.

Phenolic compounds profile of water and ethanol extracts of Euphorbia hirta L. leaves showing antioxidant and antifungal properties

The bioactive chemical constituents of water and ethanol extracts of Euphorbia hirta L. leaves have been identified and quantified using an un-targeted mass spectrometric approach. The study allowed the tentative identification of 123 individual phenolic compounds and 18 non-phenolic phytochemicals, most of them described in Euphorbia hirta L. leaves for the first time. Gallotannins, hydroxybenzoic and hydroxycinnamic acids were the most abundant phenolic classes in Euphorbia hirta L. leaves, representing together the 71.5% (26.3%, 25.2% and 20%, respectively) of the total amount of identified phenolics. The main phenolic compounds detected were tri-O-galloyl-glucose isomers, feruloyl-coniferin, tetra-O-galloyl-glucose isomers, di-O-galloyl-glucose isomers, ethyl-gallic acid, protocatechuic acid-O-pentoside-O-hexoside, 5-O-caffeoyl-quinic acid trans isomer and digalloyl-quinic acid. Feruloyl-coniferin was found to be approximately six times more concentrated in the ethanol extract with respect to the water extract. The ethanol extract exhibited higher ABTS (1338.3 ± 85.3 and 802.3 ± 91.0 μmol ascorbic acid equivalent/gram of dry extract, respectively) and superoxide anion (2014.6 ± 78.6 and 1528.0 ± 111.7 μmol ascorbic acid equivalent/gram of dry extract, respectively) scavenging abilities than the water extract. Additionally, the ethanol extract also showed a remarkable anti-fungal effect against Fusarium oxysporum f. sp. vasinfectum, Alternaria solani and Rhizoctonia solani. This study provides new information about Euphorbia hirta L., offering reasons to promote this plant species as rich source of phenolics and an excellent source of antifungal molecules that might have a prospective use in controlling fungal diseases of vegetable crops.

Fungicidal properties and insights on the mechanisms of the action of volatile oils from Amazonian Aniba trees

The Amazonian Aniba species are world-renowned for their essential oils (EOs). The molecules derived from EOs have been intensively investigated in regards to their potential for disease control in plants. The aim of this study was to investigate the antifungal properties of Aniba canelilla EO (ACEO) and Aniba parviflora EO (APEO) when used against eight phytopathogenic fungi. Gas chromatography-mass spectrometry (GC–MS) analysis of oils showed that 1-nitro-2-phenylethane (∼80%) and linalool (∼40%) are the major compounds in ACEO and APEO, respectively. The ACEO and APEO treatments displayed remarkable antifungal effects against Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, Fusarium solani, Alternaria alternata, Colletotrichum gloeosporioides, Colletotrichum musae and Colletotrichum guaranicola, for which the IC50 values ranged from 0.05 to 0.28 μL mL−1 and 0.17 to 0.63 μL mL−1, respectively. Furthermore, the oil caused the inhibition of conidial germination by at least 83% for ACEO and 78% for APEO. The ACEO and APEO at 5 μL mL−1 induced leakage of nucleic acids and protein, suggesting that inhibition could be linked to the breakdown of membrane integrity of the conidia. In addition, the detection of fluorescent dye propidium iodide (PI) on F. solani conidia treated with ACEO and APEO indicates damage on the conidia cytoplasmic membrane. The findings of this study may be of biotechnological interest for the development of new plant protection products, with the advantage of being less harmful than the agrochemicals currently available.

Antifungal Properties of Two Volatile Organic Compounds on Barley Pathogens and Introduction to Their Mechanism of Action.

This study evaluated the antifungal effects of various volatile organic compounds (VOCs) against two common pathogens: Fusarium culmorum and Cochliobolus sativus. Among the various VOCs, methyl propanoate (MP) and methyl prop-2-enoate (MA) exhibited remarkable antifungal effects under different experimental conditions (direct or indirect contact) and at different concentrations (500–1000 μM). In addition, the type of antifungal effect (fungistatic or fungicidal) appeared to be strongly correlated with the VOC concentrations. Additional tests revealed that both molecules increased membrane permeability of pathogenic spores, which resulted in a decreased efflux of K+ ions into the intracellular medium.

Bacterial iturins mediate biocontrol activity of Bacillus sp. against postharvest pear fruit‐rotting fungi

AbstractA potential antagonist, Bacillus sp. LYLB4 isolated from pear fruits, was tested for its antifungal activity against postharvest pear pathogens. LYLB4 had a remarkable antifungal effect on Botryosphaeria dothidea. Although it showed a weak inhibition effect on the growth of Rhizopus stolonifer on potato dextrose agar (PDA) plates, LYLB4 almost completely destroyed R. stolonifer during direct contact in potato dextrose broth (PDB). LYLB4 treatment was able to significantly reduce disease incidence (by 68.9% and 100%, respectively) and lesion diameter (by 68.7% and 100%, respectively) of ring rot caused by B. dothidea and soft rot caused by R. stolonifer in pears. LYLB4 also suppressed several other phytopathogens in vitro, suggesting a broad‐spectrum antagonistic activity against fungal pathogens. 16S rRNA and gyrA sequence analysis indicated that LYLB4 is closely related to B. velezensis. Genome mining indicated that LYLB4 had 11 secondary metabolites encoding clusters, but that the surfactin and fengycin gene clusters may not be functional because of a large deletion. Matrix‐assisted laser desorption ionization‐time of flight mass spectra (MALDI‐TOF‐MS) demonstrated that iturins were the major lipopeptides, and that C16/C17 Bacillomycin D synthesis was stimulated when LYLB4 was co‐cultured with B. dothidea compared to the control. Overall, these results demonstrate that the main biocontrol mechanism adopted by LYLB4 could be through the production of toxic metabolites and direct contact with pathogens.

Antimicrobial guaianolide sesquiterpenoids from leaves of the Saudi Arabian plant Anvillea garcinii

Anvillea garcinii is a medicinal plant used in the Arab region for intestinal diseases, lungs and liver diseases, digestive problems, and as an anti-diabetic. Repeated chromatographic purifications of A. garcinii leaves led to the isolation of two undescribed guaiane sesquiterpene lactones (1–2), along with four known germacranolides (3–6). The structures of the new compounds were established using spectroscopic (1D, 2D NMR) and spectrometric methods (ESIMS). Compounds 1 and 2 were shown to possess hydroxyl substituents at position 9, a structural feature rarely reported in guaianolide-type sesquiterpenes. The antimicrobial activity of 1–6 was screened against five different gram-positive/negative bacteria and the fungi Candida albicans and C. parapsilosis. Compounds 1 and 2 displayed remarkable antifungal effect against C. albicans and C. parapsilosis and potent antibacterial activities against Staphylococcus aureus.

CARACTERIZACIÓN FITOQUÍMICA DEL EXTRACTO HIDROALCOHÓLICO DEL FRUTO DE Bromelia pinguin Y EVALUACIÓN DE SU ACTIVIDAD ANTIFÚNGICA FRENTE A UN HONGO AISLADO DEL FRUTO DE CACAO (Theobroma cacao L.) EN ESTADO DE PUDRICIÓN.

Se evaluó el efecto antifúngico del extracto hidroalcohólico de fruto de B. pinguin frente a un hongo aislado de frutos enfermos en estado de pudrición de Cacao (Theobroma cacao L.) mediante un ensayo de inhibición de crecimiento micelial empleando el método de dilución en agar. El extracto tuvo un efecto antifúngico bastante notorio en un rango de concentraciones entre 2,5 y 10 % (V/V) y se pudo evidenciar además una fuerte relación dosis-respuesta. Un análisis fitoquímico preliminar, permitió identificar flavonoides, antraquinonas, taninos, saponinas y glucósidos cardiotónicos como los principales metabolitos secundarios presentes en el extracto hidroalcohólico de B. pinguin; sin embargo, aquí se discute sobre la Pinguinaína, como principal responsable de dicha actividad.