Vatcharin Rukachaisirikul

Anthraquinone, cyclopentanone, and naphthoquinone derivatives from the sea fan-derived fungi Fusarium spp. PSU-F14 and PSU-F135.

Five new metabolites, fusaranthraquinone (1), fusarnaphthoquinones A-C (2-4), and fusarone (5), were isolated from the sea fan-derived fungi Fusarium spp. PSU-F14 and PSU-F135 along with 18 known compounds. The structures were elucidated on the basis of spectroscopic evidence. Their antibacterial, antifungal, antimycobacterial, antimalarial, and cytotoxic activities were examined.

Phthalide and isocoumarin derivatives produced by an Acremonium sp. isolated from a mangrove Rhizophora apiculata.

Nine new fungal metabolites, one phthalide derivative, acremonide (1), and eight isocoumarin derivatives, acremonones A-H (2-9), were isolated from the mangrove-derived fungus Acremonium sp. PSU-MA70 together with 10 known compounds. Their structures were determined by NMR analysis. The known 8-deoxytrichothecin and trichodermol exhibited moderate antifungal activity against Candida albicans and Cryptococcus neoformanns, respectively.

Metabolites from the endophytic fungus Xylaria sp. PSU-D14

Glucoside derivatives, xylarosides A (1) and B (2), were isolated from the broth extract of the endophytic fungus Xylaria sp. PSU-D14 along with two known compounds, sordaricin (3) and 2,3-dihydro-5-hydroxy-2-methyl-4H-1-benzopyran-4-one (4). The structures were assigned by spectroscopic methods. Sordaricin (3), one of the known metabolites, exhibited moderate antifungal activity against Candida albicans ATCC90028 with a MIC value of 32 microg/ml.

Sesquiterpene and Xanthone Derivatives from the Sea Fan-Derived Fungus Aspergillus sydowii PSU-F154

Three new sesquiterpenes, named aspergillusenes A and B and (+)-(7S)-7-O-methylsydonic acid, and two new hydrogenated xanthone derivatives, named aspergillusones A and B, were isolated from the sea fan-derived fungus Aspergillus sydowii PSU-F154 together with 10 known compounds. Their structures were identified on the basis of spectroscopic data. The isolated compounds were evaluated for their antioxidant activity.

Epoxydons and a Pyrone from the Marine-Derived Fungus Nigrospora sp. PSU-F5

Nigrospoxydons A-C (1- 3) and nigrosporapyrone (4), four new metabolites, were isolated from the marine-derived fungus Nigrospora sp. PSU-F5 together with nine known compounds. Their structures were elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopic techniques. The antibacterial activity against the standard Staphylococcus aureus ATCC 25923 and methicillin-resistant S. aureus was evaluated.

A 17-Diarylheptanoid from Alpinia conchigera

Abstract The rhizomes of Alpinia conchigera were found to contain a new 1,7-diarylheptanoid, which was identified as 1,7-diphenyl-3,5-heptanedione, together with four other diarylheptanoids, two flavonoids and four phenylpropanoids.

Antioxidative and Free Radical Scavenging Activities of Some Plants Used in Thai Folk Medicine

Abstract Ten methanol extracts from various parts of seven medicinal plants, Angiopteris evecta Hoffm.., (Marattiaceae) Citrus hystrix DC.., (Rutaceae) Laurentia longiflora (L.). Peterm.., (Campanulaceae) Nelumbo nucifera Gaertn.., (Nelumbonaceae), Piper sarmentosum Roxb.., (Piperaceae), Portulaca oleracea Linn.., (Portulacaceae) and Stachytarphera indica (L.). Vahl. (Verbenaceae), commonly used in Thai traditional medicine, were evaluated for their antioxidative and free radical scavenging activities. Among them, only that prepared from sacred lotus (N. nucifera) leaves exhibited a pronounced activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay with an IC50 of 90 µg/ml, compared with an IC50 of 30 µg/ml for the butylated hydroxytoluene (BHT) control. The same extract was also found to be the most potent in removing the superoxide anion () radical and in inhibiting the 2,2′-azo-bis.-(2-amidinopropane) dihydrochloride (AAPH)-induced erythrocyte hemolysis and lipid peroxidation in a rat brain homogenate. The extract from leaves and peels of the Kaffir lime (C. hystrix.) exerted the strongest effect on production of the hydroxyl radical (OH·). They conferred a twice greater protection of deoxyribose from OH· than did tannin. However, none of the extracts examined in this study showed a significant pro-oxidant action in the bleomycin-dependent DNA oxidation system.

Pyrone derivatives from the marine-derived fungus Nigrospora sp. PSU-F18.

Pyrones, named nigrosporapyrones A-D (1-4), and five known compounds were isolated from the marine-derived fungus Nigrospora PSU-F18. Their structures were elucidated on the basis of spectroscopic evidence. The antibacterial activity against the standard Staphylococcus aureus ATCC 25923 and methicillin-resistant S. aureus was evaluated.

Cyclohexene, diketopiperazine, lactone and phenol derivatives from the sea fan-derived fungi Nigrospora sp. PSU-F11 and PSU-F12

Nigrosporanenes A (1) and B (2), two new cylohexene derivatives, and tyrosol (3) were isolated from the sea fan-derived fungus Nigrospora sp. PSU-F11, whereas five known compounds: 4-hydroxybenzoic acid (4), aplysiopsene D (5), 3-isochromanone (6), (−)-drimenin (7) and diketopiperazine derivative (8), were obtained from the fungus Nigrospora sp. PSU-F12. Their structures were established by spectroscopic evidence. We also tested their cytotoxic (on African green monkey kidney fibroblast and breast cancer cells), antioxidant (in the DPPH assay), and antibacterial (against the standard Staphylococcus aureus ATCC 25923 and methicillinresistant S. aureus) activities.

Antimicrobial potential of endophytic fungi derived from three seagrass species: Cymodocea serrulata, Halophila ovalis and Thalassia hemprichii.

Endophytic fungi from three commonly found seagrasses in southern Thailand were explored for their ability to produce antimicrobial metabolites. One hundred and sixty endophytic fungi derived from Cymodocea serrulata (Family Cymodoceaceae), Halophila ovalis and Thalassia hemprichii (Family Hydrocharitaceae) were screened for production of antimicrobial compounds by a colorimetric broth microdilution test against ten human pathogenic microorganisms including Staphylococcus aureus ATCC 25923, a clinical isolate of methicillin-resistant S. aureus, Escherichia coli ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Candida albicans ATCC 90028 and NCPF 3153, Cryptococcus neoformans ATCC 90112 and ATCC 90113 and clinical isolates of Microsporum gypseum and Penicillium marneffei . Sixty-nine percent of the isolates exhibited antimicrobial activity against at least one test strain. Antifungal activity was more pronounced than antibacterial activity. Among the active fungi, seven isolates including Hypocreales sp. PSU-ES26 from C . serrulata , Trichoderma spp. PSU-ES8 and PSU-ES38 from H . ovalis , and Penicillium sp. PSU-ES43, Fusarium sp. PSU-ES73, Stephanonectria sp. PSU-ES172 and an unidentified endophyte PSU-ES190 from T . hemprichii exhibited strong antimicrobial activity against human pathogens with minimum inhibitory concentrations (MIC) of less than 10 µg/ml. The inhibitory extracts at concentrations of 4 times their MIC destroyed the targeted cells as observed by scanning electron microscopy. These results showed the antimicrobial potential of extracts from endophytic fungi from seagrasses.