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    Cytotoxic and antibacterial depsidones from the endophytic fungus Chaetomium brasiliense isolated from Thai rice
    (2022-01-01)
    Promgool, Trinop
    ;
    Kanokmedhakul, Kwanjai
    ;
    Leewijit, Thianrat
    ;
    ;
    Four new depsidones, mollicellins V-Y (1-4), together with eight known depsidones (5-12) were isolated from the endophytic fungus, Chaetomium brasiliense, detached from stems of Thai rice. Their structures were determined by extensive spectroscopic methods. Mollicellins X, H, and F (3, 8 and 10) showed potent cytotoxicity against the human oral epidermoid carcinoma (KB) cell line, and mollicellin F (10) also showed a potent cytotoxicity against the human hepatocellular carcinoma (HepG2) cell line. Besides, mollicellin B (11) exhibited cytotoxicity against the colorectal adenocarcinoma (HT-29) cell line. Moreover, most of the isolated depsidones displayed potent antibacterial activity against Gram-positive bacteria, Bacillus cereus and Bacillus subtilis, and several of them showed moderate activity against Methicillin-resistant Staphylococcus aureus (MRSA) and clinical isolates of S. aureus. In addition, a few of them also showed moderate activity against a Gram-negative bacteria Pseudomonas aeruginosa.
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    Antifungal activity of microbial nanoparticles derived from Chaetomium spp. against Magnaporthe oryzae causing rice blast
    (2020-01-01) ; ;
    Kanokmedhakul, Somdej
    ;
    Kanokmedhakul, Kwanjai
    ;
    The Magnaporthe oryzae isolate PO2 was proven to cause rice blast var. PSL 2 in this study. Chaetomium elatum, Chaetomium lucknowense and Chaetomium brasiliense were antagonised to M. oryzae. The hexane extract of C. brasiliense gave the highest inhibition of the spore production with an ED<inf>50</inf> of 35 ppm, the EtOAC extract of C. lucknowense inhibited the spore production at 57 ppm and the EtOAC extracts of C. elatum inhibited the spore production at 106 ppm. The nano-CLM (C. lucknowense) inhibited the spore production at 5.24 ppm, the nano-CBH (C. brasiliense) inhibited the spore production at 6.86 ppm and the nano-CEE (C. elatum) inhibited the spore production at 7.89 ppm. The rice leaves treated with nano-CBH from C. brasiliense produced Sakuranertin and Oryzalexin B as seen on the thin layer chromatography where the Rf value was 0.08 assumed to be Sakuranertin, and the R<inf>f</inf> value of 0.28 supposed to be Oryzalexin B. It was found that the nanoparticles act as elicitors to induce immunity in rice plants through the production of phytoalexin.
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    New Pyrrolobenzoxazine Sesquiterpenoid Derivatives from the Fungus Talaromyces trachyspermus
    (2021-07-13)
    Chaiyosang, Boonyanoot
    ;
    Kanokmedhakul, Kwanjai
    ;
    ; ;
    Soytong, Mayamor
    Three new pyrrolobenzoxazine sesquiterpenoids, talatrachyoxazines A-C (1-3), together with fourteen known compounds (4-17), were isolated from the fungus Talaromyces trachyspermus EU23. Their structures were identified by spectroscopic evidence and mass spectrometry. The absolute configurations of 1-3 were determined by NOESY data and comparison of their calculated and experimental electronic circular dichroism (ECD) spectra. Compound 1 showed cytotoxic activity against HelaS3, KB, HT-29, MCF-7, and HepG2 cell lines with IC50 values of 7, 11, 10, 12, and 10 μM, respectively. Compounds 1 and 14 showed weak antibacterial activity against the gram-positive bacteria Bacillus cereus and Bacillus subtilis, while 1-3 and 14 showed weak antibacterial activity against the gram-negative bacterium Pseudomonas aeruginosa. In addition, compound 1 showed weak antibacterial activity against Escherichia coli.
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    Control of rice blast disease caused by Magnaporthe oryzae by application of antifungal nanomaterials from Emericella nidulans
    (2022-01-01) ; ;
    Kanokmedhakul, Somdej
    Metabolites of Emericella nidulans (EN) were separated by chromatographic methods from crude hexane included emericellin and sterigmatocystin, while crude ethyl acetate found demethylsterigmatocystin. These metabolites proved to be antagonistic to Magnaporthe oryzae, the causal agent of rice blast. Crude extracts and nano-particles derived from EN inhibited M. oryzae. The ethyl acetate crude extract derived inhibited M. oryzae with an effective dose (ED<inf>50</inf>) of 66 μg/mL. The nanoparticles showed better inhibition of M. oryzae than crude extracts at low concentrations. Nanoparticles, namely from crude ethyl acetate, crude methanol and crude hexane of EN were active against M. oryzae with ED<inf>50</inf> of 4.2 μg/mL, 4.5 μg/mL, 8.9 μg/mL, respectively. It detected sakuranetin (rate of flow value is 0.09) in nano-EN treated rice leaves. These nanoparticles inhibited M. oryzae and acted as a new elicitor to induce immunity.
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    Natural product of nano-particles constructed from chaetomium spp. To control rice blast disease caused by magnaporthe oryzae
    (2020-01-01) ; ;
    Kanokmedhakul, Somdej
    ;
    Kanokmedhkul, Kwanjai
    ;
    Nanoparticles containing active compounds derived from Chaetomium cochliodes (CTh05) was tested to control rice blast disease caused by Magnaporthe oryzae isolate PO1. The causal agent of rice blast on leaves of rice var. RD57 was isolated. M. oryzae and C. cochliodes were identified morphologically and confirmed by molecular phylogenetic. M. oryzae was demonstrated to be pathogenic, causing blast of rice var. RD57. Biculture tests demonstrated that C. cochliodes could suppress the growth of M. oryzae. The crude metabolites of C. cochliodes (CCoH, CCoE and CCoM) at the concentrations of 10-1000 ppm expressed antifungal activity against the M. oryzae, resulting in inhibited spore production in 12 days with effective dose (ED<inf>50</inf>) values of 85, 144 and 374 ppm, respectively. The nanoparticles sizes of nano-CCoH, nano-CCoE and nano-CCoM were ranged between 567-611, `422-566 and 415-472 nm, respectively. Nanoparticles derived from C. cochliodes (nano-CCoH, nano-CCoE and nano-CCoM) at concentrations of 3-15 ppm significantly inhibited M. oryzae in 12 days with ED<inf>50</inf> values of 9, 16 and 33 ppm, respectively. In vivo experiments revealed a reduction of 38% in blast disease after application of nanoparticles constructed from crude extract mixtures from C. cochliodes at 10 ppm for 30 days. Tricyclazole resulted in reduction of blast disease by 29%. Rice blast disease was decreased in 30 days after applying nano-CCoM at the concentration of 7 ppm (60% disease reduction), followed by nanoCCoE and nanoCCoH with disease reduction of 58 and 50% respectively, and tricyclazole resulted in a 56% reduction in rice blast.
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    Meroterpenoid pyrones, alkaloid and bicyclic brasiliamide from the fungus Neosartorya hiratsukae
    (2020-04-01)
    Paluka, Jakkapat
    ;
    Kanokmedhakul, Kwanjai
    ;
    Soytong, Mayamor
    ;
    ;
    Yahuafai, Jantana
    Two new meroterpenoid pyrones, chevalone G (1) and aszonapyrone C (2), a new indole alkaloid, 7-chlorofischerindoline (3) and a new bicyclic brasiliamide, brasiliamide H (4), together with sixteen known compounds, 5–20 were isolated from the fungus Neosartorya hiratsukae. Their structures were established on the basis of spectroscopic evidence. The antibacterial activity and the cytotoxic activity of new compounds were evaluated.
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    Bioactive xanthoquinodins and epipolythiodioxopiperazines from Chaetomium globosum 7s-1, an endophytic fungus isolated from Rhapis cochinchinensis (Lour.) Mart
    (2020-02-16)
    Tantapakul, Cholpisut
    ;
    Promgool, Trinop
    ;
    Kanokmedhakul, Kwanjai
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    ;
    A new xanthoquinodin B9 (1), together with two known xanthoquinodins, xanthoquinodin A1 (2) and xanthoquinodin A3 (3), three epipolythiodioxopiperazines, chetomin (4), chaetocochin C (5) and dethio-tetra(methylthio)chetomin (6), and four other compounds, chrysophanol (7), emodin (8), alatinone (9), and ergosterol (10) were isolated from the endophytic fungus Chaetomium globosum 7s-1, isolated from Rhapis cochinchinensis (Lour.) Mart. All isolated structures were established based on their spectroscopic data analyses. Compounds 1–6 showed antibacterial activity against Gram positive bacteria with MICs ranging from 0.02 pM to 10.81 µM. Compounds 1–6 also exhibited cytotoxicity against KB, MCF-7 and NCI-H187 cancer cell lines (IC<inf>50</inf> 0.04–18.40 µM). However, they were cytotoxic towards a normal cell line (Vero cell) with IC<inf>50</inf> values ranging from 0.04 to 3.86 µM.
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