Cytotoxic Polyhydroxy-Isoprenoids from Neodidymelliopsis negundinis.

Fungal-derived natural products continue to play a pivotal role in the discovery of drug agents for human, veterinary, and general agricultural use. The fungus Neodidymelliopsis negundinis presents a significant saprobic ascomycete whose metabolites remained hitherto unstudied. Herein we report the isolation of eight unprecedented secondary metabolites named neodidymelliosides A and B (1 and 2), neodidymelliol A (3), and neodidymellioic acids A-E (4-8) produced by the submerged cultures of the fungus. Compound 1 proved to be the most active compound, with IC50 values ranging between 4.8 and 8.8 µM against KB3.1 (cervix), PC-3 (prostate), MCF-7 (breast), SKOV-3 (ovary), A431 (skin), and A549 (lung) cell lines. Compound 1 revealed significant inhibition of Staphylococcus aureus and Candida albicans biofilms.

Lasiodipline G and other diketopiperazine metabolites produced by Lasiodiplodia chiangraiensis.

Lasiodiplodia fungi are known to colonize plants as both pathogens and/or endophytes; hence, they can be exploited for their beneficial roles. Many compound classes from the genus have exhibited their potential biotechnological applications. Herein, we report two new metabolites 1 and 2 together with three known cyclo-(D-Ala-D-Trp) (3), indole-3-carboxylic acid (4) and a cyclic pentapeptide clavatustide B (5), isolated from the submerged cultures of a recently described species L. chiangraiensis. Chemical structures of the isolated compounds were determined by extensive NMR spectroscopic analyses together with HRESIMS. The absolute configurations of the new compounds were established based on comparing experimental and calculated time-dependent density functional theory circular dichroism (TDDFT-ECD) spectra. Compound 1 exhibited significant cytotoxic activities against an array of cell lines with IC50 values of 2.9-12.6 µM, as well as moderate antibacterial effects.

Characterisation of teaghrelin-like principles from Assam tea cultivated in Thailand.

Teaghrelins were identified as unique acylated flavonoid tetraglycosides and firstly reported in Chin-shin oolong tea. In the present study, two new teaghrelin-like compounds (1 and 2) were purified and characterised from Assam tea varieties collected in Thailand. Their chemical structures were constructed by the spectroscopic and spectrometric analysis. These two teaghrelin-like compounds were also not supposed to exhibit significant ghrelin receptor affinity according to the structural comparison with those teaghrelin-like compounds previously reported. In addition, compounds 1 and 2 did not display notable anti-inflammatory activity in human neutrophils assay.[Formula: see text].

Antifungal properties of volatile organic compounds produced by Daldinia eschscholtzii MFLUCC 19-0493 isolated from Barleria prionitis leaves against Colletotrichum acutatum and its post-harvest infections on strawberry fruits.

Fungal endophytes are microorganisms living symbiotically with a host plant. They can produce volatile organic compounds (VOCs) that have antimicrobial activity. This study aimed to isolate endophytic fungi from Barleria prionitis plants grown in Thailand and to investigate the antifungal properties of their VOCs against Colletotrichum acutatum, a causal agent of anthracnose disease on post-harvest strawberry fruits. A total of 34 endophytic fungi were isolated from leaves of B. prionitis. The VOCs produced from each individual isolate were screened for their antifungal activity against C. acutatum using a dual-culture plate method. From this in vitro screening experiment, the VOCs produced by the endophytic isolate BP11 were found to have the highest inhibition percentage (80.3%) against the mycelial growth of C. acutatum. The endophytic isolate BP11 was molecularly identified as Daldinia eschscholtzii MFLUCC 19-0493. This strain was then selected for an in vivo experiment. Results from the in vivo experiment indicated that the VOCs produced by D. eschscholtzii MFLUCC 19-0493 were able to inhibit infections by C. acutatum on organic fresh strawberry fruits with an average inhibition percentage of 72.4%. The quality of the pathogen-inoculated strawberry fruits treated with VOCs produced by D. eschscholtzii MFLUCC 19-0493 was evaluated. Their fruit firmness, total soluble solids, and pH were found to be similar to the untreated strawberry fruits. Solid phase microextraction-gas chromatographic-mass spectrometric analysis of the VOCs produced by D. eschscholtzii MFLUCC 19-0493 led to the detection and identification of 60 compounds. The major compounds were elemicin (23.8%), benzaldehyde dimethyl acetal (8.5%), ethyl sorbate (6.8%), methyl geranate (6.5%), trans-sabinene hydrate (5.4%), and 3,5-dimethyl-4-heptanone (5.1%). Each major compound was tested for its antifungal activity against C. acutatum using the in vitro assay. While all these selected VOCs showed varying degrees of antifungal activity, elemicin was found to possess the strongest antifungal activity. This work suggests that D. eschscholtzii MFLUCC 19-0493 could be a promising natural preservative for controlling C. acutatum associated anthracnose disease in strawberry fruits during the post-harvest period.

In vitro and in vivo antifungal activity of Cuminum cyminum essential oil against Aspergillus aculeatus causing bunch rot of postharvest grapes.

Bunch rot in grapes is an aggressive disease and needs to be controlled during the postharvest period. We investigate the antifungal potential of Zanthoxylum bungeanum Maxim., Zanthoxylum rhetsa, Cuminum cyminum, Coriandrum sativum, and Zingiber montanum (J. Koenig) Link ex A. Dietr. essential oils against Aspergillus aculeatus that cause bunch rot disease on postharvest grapes. C. cyminum essential oil exhibited stronger significantly inhibition percentage of 95.08% than other treatments in in vitro assay. Cumin aldehyde (33.94%) and α-terpinen-7-al (32.20%) were identified as major volatile compounds in C. cyminum oil. Antifungal potential of C. cyminum oil was then tested in conidia germination and in vitro tests compared to cumin aldehyde and α-terpinen-7-al. Their EC50 values against the conidial germination were also estimated. Significant reduction of conidia germination was also detected in C. cyminum essential oil and cumin aldehyde at a concentration of 1,000 and 100 µg/mL, respectively. EC50 values of the C. cyminum essential oil, cumin aldehyde, and α-terpinen-7-al were 67.28 µg/mL, 9.31 µg/mL, and 13.23 µg/mL, respectively. In vivo assay, the decrease of the disease severity (0.69%) and incidence (1.48%) percentage of A. aculeatus on grape berries treated at 1,000 µg/mL of C. cyminum essential oil was significantly greater than that obtained from other treatments after 10 days incubation. In addition, grape berries treated with C. cyminum essential oil decreased weight loss and retained fruit firmness. The changing of total soluble solids, total phenolic content, and antioxidant activity are also delayed in treated fruits. Therefore, essential oil of C. cyminum may be applied as a biological antifungal agent to control A. aculeatus in postharvest grapes without any negative effects on its quality.

Antifungal activity of 8-methoxynaphthalen-1-ol isolated from the endophytic fungus Diatrype palmicola MFLUCC 17-0313 against the plant pathogenic fungus Athelia rolfsii on tomatoes.

Thirty-four endophytic fungal isolates were obtained from the leaves of the medicinal plant Polyscias fruticosa, and their antagonistic activities against the growth of the common tomatoes plant pathogenic fungus Athelia rolfsii were initially screened using a dual culture assay. The endophytic fungus MFLUCC 17-0313, which was later molecularly identified as Diatrype palmicola, displayed the highest inhibition percentage (49.98%) in comparison to the others. This fungus was then chosen for further evaluation. Its culture broth and mycelia from a 10 L scale were separated and extracted using ethyl acetate, methanol, and hexane. Each extract was tested for antifungal activity against the same pathogen using a disc diffusion assay. Only the crude hexane extract of fungal mycelium showed antifungal activity. The hexane extract was fractioned using sephadex gel filtration chromatography and each fraction was tested for antifungal activity until the one with the highest inhibition percentage was obtained. The bioactive compound was identified as 8-methoxynaphthalen-1-ol using nuclear magnetic resonance spectroscopy and mass spectrometry. The minimum inhibition concentration of 8-methoxynaphthalen-1-ol was demonstrated at 250 µg/mL against the selected pathogen. Using the leaf assay, the solution of 8-methoxynapthalen-1-ol was tested for phytotoxic activity against A. rolfsii and was found to have no phytotoxic effects. These results showed that 8-methoxynaphthalen-1-ol has the potential for controlling the growth of A. rolfsii, the cause of Southern blight disease on tomatoes. This study may provide the foundation for future use of this compound as a biofungicide.

Essential Oil Compositions and Antibacterial and Antioxidant Activities of Five Lavandula stoechas Cultivars Grown in Thailand.

The essential oils of five Lavandula stoechas cultivars grown in Thailand were characterized for their volatile compounds using GC-FID and GC/MS methods as well as screened for antibacterial and antioxidant activities. Dried aerial parts, including flowers and stems from each cultivar, were subjected to hydrodistillation for 4 h. The essential oil yields were 0.18 %-0.82 % w/w. Of the 95 compounds detected and identified, 1,8-cineole, fenchone, and camphor were considered the major compounds. Essential oil from each cultivar demonstrated different patterns of antibacterial activity and a variety of antioxidant properties. The highest antibacterial activity, MIC=0.39 mg mL-1 , was observed from the essential oil of L. stoechas 'major' (against Klebsiella pneumoniae and Salmonella typhimurium) and the essential oil of L. stoechas 'white lavender' (against S. typhimurium). The essential oil of L. stoechas×viridis 'St. Brelade' possessed the highest antioxidant capacity, as determined by the DPPH and ABTS assays (IC50 of 67.65 and 89.26 mg mL-1 , respectively). The results indicated that some of these essential oils could be used as key ingredients in lavender oil products in Thailand to increase their therapeutic efficacy, depending on their intended application.

Production of eugenol from fungal endophytes Neopestalotiopsis sp. and Diaporthe sp. isolated from Cinnamomum loureiroi leaves.

Endophytic fungi, which colonize within a host plant without causing any apparent diseases, have been considered as an important source of bioactive secondary metabolites containing antimicrobial and antioxidant activities. The aim of this research was to isolate the endophytic fungi of Cinnamomum loureiroi and then to screen their antimicrobial and antioxidant activities. A total of 11 fungal endophytes were isolated from healthy leaves of Cinnamomum loureiroi belonging to six genera: Botryosphaeria, Colletotrichum, Diaporthe, Fusarium, Neopestalotiopsis, and Pestalotiopsis. All isolated strains were cultured and further extracted with ethyl acetate solvent. Antimicrobial activity of all crude endophytic fungal extracts was analyzed using disc diffusion assay against six bacterial and two fungal pathogens. Crude extracts of strains MFLUCC15-1130 and MFLUCC15-1131 showed broad-spectrum antimicrobial activity against all tested pathogens. Activity against Bacillus cereus and Staphylococcus epidermidis was notable, showing the lowest minimum inhibitory concentration at 3.91 µg/mL. Antioxidant activity of all crude endophytic fungal extracts was also evaluated based on 2,2-diphenyl-1-picrylhydrazyl assay. Significant antioxidant activity was detected in the crude extracts of fungus MFLUCC15-1130 and MFLUCC15-1131 with IC50 of 22.92 ± 0.67 and 37.61 ± 0.49 µg/mL, respectively. Using molecular identification, MFLUCC15-1130 and MFLUCC15-1131 were identified as Neopestalotiopsis sp. and Diaporthe sp., respectively. The major chemical constituents produced by both crude extracts were identified by gas chromatography-mass spectrometry. Eugenol, myristaldehyde, lauric acid, and caprylic acid were the primary antimicrobial and antioxidant compounds in both crude extracts. This is the first report of eugenol being a biologically active compound of Neopestalotiopsis sp. and Diaporthe sp. fungal endophytes. Eugenol has been reported as antimicrobial and antioxidant agents with agronomic applications. Thus the two newly-isolated endophytes may be used for eugenol production, which in turn can be used in a variety of applications.

Antibacterial potential of secondary metabolites produced by Aspergillus sp., an endophyte of Mitrephora wangii.

Mitrephora wangii, an ethnomedicinal plant, has been used as a natural antibiotic and immunity booster in Thailand. A total of 22 fungi were isolated from M. wangii flowers. The fungal isolates were categorized into six genera including Agrocybe, Aspergillus, Colletotrichum, Nigrospora, Puccinia and Ustilago. Most extracts exhibited antibacterial activity against at least one of the test bacteria. Aspergillus sp. MFLUCC16-0845 was identified as the most bioactive fungus. Chemical composition of Aspergillus sp. MFLUCC16-0845 investigated using gas chromatography-mass spectrometry indicated that the major antibacterial compound was ß-thujaplicin. Moreover, the newly isolated Aspergillus sp. MFLUCC16-0845 could be exploited as a potential source of bioactive compounds and plant defense activators. In addition, it is the first time that strain of Aspergillus sp. isolated and cultured from M. wangii flowers could produce ß-thujaplicin at high yield with strong antimicrobial spectrum, which may lead to wide utilization in producing cosmetics and clinical products.

Antibacterial and Antioxidant Metabolites of Diaporthe spp. Isolated from Flowers of Melodorum fruticosum.

Fifty-two strains of endophytic fungi were isolated from flowers of the medicinal plant Melodorum fruticosum. Seven genera were identified including Alternaria, Aspergillus, Colletotrichum, Diaporthe, Fusarium, Greeneria and Nigrospora. All strains were cultured for 30 days and further macerated in ethyl acetate solvent for 3 days. The obtained fungal extracts were examined for antibacterial activity using agar disc diffusion against nine pathogenic bacteria: Staphylococcus aureus, Bacillus subtilis, B. cereus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Shigella flexneri, Vibrio cholerae and V. parahaemolyticus. Forty-three fungal extracts exhibited antibacterial activity against at least one tested pathogen. The antioxidant properties of all extracts were also investigated by DPPH scavenging assay. Sixteen extracts displayed high antioxidant capacity (IC50 ranging from 10 to 50 µg/mL) when compared to the gallic acid and trolox standards (IC50 of 12.46 and 2.55 µg/mL, respectively). The crude extracts of Diaporthe sp. MFLUCC16-0682 and Diaporthe sp. MFLUCC16-0693 exhibited notable antibacterial and antioxidant activities. Analysis of chemical composition using gas chromatography-mass spectrometry suggested that the observed antibacterial activity of the two Diaporthe spp. was possibly due to the presence of abienol, 4-methoxy stilbene, phenethyl cinnamate and 2Z,6Z-farnesal, while their potential antioxidant activity could be attributed to phenolic compounds, such as benzene acetaldehyde, benzyl benzoate, salicylaldehyde, benzoin and benzyl cinnamate. The results suggest that the genus Diaporthe is a potential source of metabolites that can be used in a variety of applications.