Soytong, Kasem

Preferred name

Soytong, Kasem

Alternative Name

Soytong, K.

kasem.so@kmitl.ac.th

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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
;
Song, Jiaojiao
;
Soytong, Kasem
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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Elucidation of high micro-heterogeneity of an acidic-neutral trichotoxin mixture from Trichoderma harzianum by electrospray ionization quadrupole time-of-flight mass spectrometry
(2000-01-01)
Suwan, Sathorn
;
Isobe, Minoru
;
Kanokmedhakul, Somdej
;
Lourit, Nuttaya
;
Kanokmedhakul, Kwanjai
The high micro-heterogeneity of an acidic-neutral trichotoxin mixture from T. harzianum, PC01, was elucidated using a modern tandem mass spectrometer equipped with an electrospray ionization source, a hybrid quadrupole-orthogonal accelerator and a reflectron time-of-flight analyzer. The trichotoxins appeared predominantly in six possible doubly charged pseudo molecular ions with three different adducts (H, Na and K) as [M + 2H]2+, [M + H + Na]2+, [M + H + K]2+, [M + 2Na]2+, [M + Na + K]2+ and [M + 2K]2+. The singly charged pseudomolecular ions, [M + H]+, [M + Na]+ and [M + K]+, occurred only in low abundance when the cone voltages were higher than 30 V. Additional singly charged fragments, b<inf>12</inf> and y′6 (complementary N- and C-terminal fragments), were obtained in high abundance using high cone voltages. The peak patterns of both singly and doubly charged molecular adducts revealed that this trichotoxin mixture contained several components having 6-7 molecular masses with a consecutive 14 u difference among members in the same molecular adduct series. Furthermore, well resolved isotopic peaks of every doubly or singly charged ions and their reproducible peak intensity allowed the identification of the mixing of acidic trichotoxins 1 u molecular mass heavier than the neutral counterparts in the sample. Tandem mass spectrometric (MS/MS) analyses of various singly charged b<inf>12</inf> and y′6 ions supported the sequence deduction of the major and minor components and also the position of Glu in the sequences of these acidic molecules. The setting of either low or high resolution of the quadrupole mass filter unit together with a suitable variation of the collision voltage for any MS/MS precursor were the tools for extracting a number of mixed components and obtaining the major and minor sequences of these precursor peaks. The nature of the MS/MS fragmentation and the data assignment of three major doubly charged ions, [M + 2H]2+, [M + K + H]2+ and [M + 2K]2+, are demonstrated. Eleven new sequences of both acidic and neutral trichotoxins are reported. Copyright © 2000 John Wiley & Sons, Ltd.
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Antifungal activity of microbial nanoparticles derived from Chaetomium spp. against Magnaporthe oryzae causing rice blast
(2020-01-01)
Song, Jiao Jiao
;
Soytong, Kasem
;
Kanokmedhakul, Somdej
;
Kanokmedhakul, Kwanjai
;
Poeaim, Supattra
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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A bioactive triterpenoid and vulpinic acid derivatives from the mushroom Scleroderma citrinum
(2003-06-01)
Kanokmedhakul, Somdej
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Kanokmedhakul, Kwanjai
;
Prajuabsuk, Thirada
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Soytong, Kasem
;
Kongsaeree, Palangpon
A new lanostane-type triterpenoid, (20S,22S,23E)-22-O-acetyl-25-hydroxylanosta-8,23(E)-dien-3-one (1), isolated as a new natural product for the first time, methyl 4,4′-dimethoxyvulpinate (2), together with the known compound 4,4′-dimethoxyvulpinic acid (3) were isolated from the mushroom Scleroderma citrinum. Their structures were determined using spectroscopic and chemical methods, and an X-ray analysis was performed to confirm structure of 1. Compound 1 exhibited significant antiviral activity against Herpes simplex type 1. Compound 3 and two of its derivatives, the dibromo derivative 5 and acetate derivative 6, exhibited activity towards Mycobacterium tuberculosis. In addition, 5 and 6 also showed cytotoxicity against the NCI-H187 cell line.
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A new xanthone from the fungus Apiospora montagnei
(2017-01-01)
Arthan, Supakorn
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Tantapakul, Cholpisut
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Kanokmedhakul, Kwanjai
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Soytong, Kasem
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Kanokmedhakul, Somdej
A new xanthone derivative, methyl 8-hydroxy-3-hydroxymethylxanthone-1-carboxylate (1), and seven known compounds, 8-hydroxy-3-methylxanthone-1-carboxylate (2), methyl 8-hydroxy-6-methylxanthone-1-carboxylate (3), ergosterol (4), cyathisterone (5), ergosta-4,6,8(14),22-tetraen-3-one (6), calvasterone (7) and 2-hexyl-3-methylmaleic anhydride (8) were first isolated from the fungus Apiospora montagnei. Their structures were elucidated on the basis of spectroscopic analysis (UV, IR, MS, 1D, and 2D NMR). Compounds 5 and 6 showed weak to very weak cytotoxicity against cancer cell lines, NCI-H187 and KB.
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Meroditerpene pyrone, tryptoquivaline and brasiliamide derivatives from the fungus Neosartorya pseudofischeri
(2019-09-01)
Paluka, Jakkapat
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Kanokmedhakul, Kwanjai
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Soytong, Mayamor
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Soytong, Kasem
;
Kanokmedhakul, Somdej
Two new meroditerpene pyrones, chevalone F (1) and 11-hydroxychevalone E (2), a new tryptoquivaline analog, tryptoquivaline V (3) and a new brasiliamide analog, brasiliamide G (4), together with thirteen known compounds, chevalones A-C (5–7), chevalone E (8), 11-hydroxychevalone C (9), pyripyropene A (10), isochaetominine C (11), pyrrolobenzoxazine terpenoids CJ-12662 (12) and CJ-12663 (13), fischerindoline (14), eurochevalierine (15), 1,4-diacetyl-2,5-dibenzylpiperazine-3,7′′-oxide (16) and lecanorin (17) were isolated from the fungus Neosartorya pseudofischeri. Their structures were established on the basis of spectroscopic evidence. Compound 2 showed weak antibacterial activity against Escherichia coli and Salmonella enterica serovar Typhimurium, whereas compounds 7, 12, 13 and 15 showed antibacterial activity against Bacillus cereus and Staphylococcus aureus. In addition, compounds 13 and 14 showed cytotoxicity against KB and MCF-7 cancer cell lines, as well as the Vero cell line.
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Antimycobacterial anthraquinone-chromanone compound and diketopiperazine alkaloid from the fungus Chaetomium globosum KMITL-N0802
(2002-09-01)
Kanokmedhakul, Somdej
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Kanokmedhakul, Kwanjai
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Phonkerd, Nutchanat
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Soytong, Kasem
;
Kongsaeree, Palangpon
Investigation of the fungus Chaetomium globosum KMITL-N0802 led to the isolation of a novel anthraquinone-chromanone compound named chaetomanone along with seven known compounds, ergosterol, ergosteryl palmitate, chrysophanol, chaetoglobosin C, alternariol monomethyl ether, echinuline and isochaetoglobosin D. These compounds were characterized by spectroscopic methods. Chaetomanone and echinulin exhibited activity towards Mycobacterium tuberculosis.
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A new benzyl ester and ergosterol derivatives from the fungus Gymnoascus reessii
(2014-01-01)
Kitchawalit, Sasiwimon
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Kanokmedhakul, Kwanjai
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Kanokmedhakul, Somdej
;
Soytong, Kasem
A new benzyl ester, reessiate (1), anthraquinone, islandicin (2), ergosterol and seven ergosterol derivatives (3-9) were isolated from the fungus Gymnoascus reessii. All structures were identified by spectroscopic methods. This is the first report of their isolation from this fungus. Compounds 4-7 and 9 exhibited antimalarial activity against Plasmodium falciparum with IC <inf>50</inf> values in the range of 3.3-4.5 μg/mL. In addition, 4 showed cytotoxicity against KB, MCF7 and NCI-H187 cancer cell lines. It was found that 4 has cytotoxic effect to MCF7 (IC<inf>50</inf> = 7.9 μg/mL) lower than Doxorubicin (IC<inf>50</inf> = 8.5 μg/mL). © 2014 Taylor & Francis.
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Bioactive azaphilones from the fungus Penicillium multicolor CM01
(2016-06-01)
Hemtasin, Chulida
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Kanokmedhakul, Somdej
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Moosophon, Panawan
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Soytong, Kasem
;
Kanokmedhakul, Kwanjai
Two new azaphilones, dechloroisochromophilone II (1) and epi-isochromophilone III (2), a new natural product, 5-hydroxy-4-methoxy-5,6-dihydro-2H-pyran-2-one (3), together with eleven known compounds, 4-14 were isolated from the fungus, Penicillium multicolor CM01. Their structures were elucidated by spectroscopic methods. Compounds 2, 8, 10 and 11 exhibited antimalarial activity against Plasmodium falciparum (IC<inf>50</inf> 2.1-7.8 μg/mL), while compounds 9 and 10 showed antimycobacterial activity against Mycobacterium tuberculosis (MIC 6.2 and 50.0 μg/mL, respectively). Compounds 2, 4, and 7-11 showed cytotoxicity against three cancer cell lines, KB, MCF-7 and NCI-H187 (IC<inf>50</inf> 2.2-35.2 μg/mL). In addition, compounds 1, 5-8 and 11 showed a minimum inhibition requirement to acetylcholinesterase (AChE) assay in the range of 0.03-0.25 nM.
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Chemical constituents from the fungus Chaetomium cupreum RY202
(2015-05-01)
Panthama, Natcha
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Kanokmedhakul, Somdej
;
Kanokmedhakul, Kwanjai
;
Soytong, Kasem
Two new angular types of azaphilones, isochromophilonol (1) and ochrephilonol (2), together with ten known compounds (3-12), were isolated from Chaetomium cupreum RY202. Their structures were established on the basis of spectroscopic data and the absolute configurations of 1 and 3 were determined by the modified Mosher's method. Compounds 1, 2 and 4 showed moderated cytotoxicity against KB and NCI-H187 cell lines (IC<inf>50</inf> 9.63-32.42 μg/mL).

Soytong, Kasem

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