VK-12

Chemical investigation of the marine-derived endophytic fungus Ascomycota sp. VK12 resulted in isolation and identification of a new compound, (3R)-(3',5'-dihydroxyphenyl)butan-2-one (1) and five known ones: AGI-7 (2), sescandelin (3), sescandelin-B (4), 4-hydroxybenzaldehyde (5), and hydroxysydonic acid (6). The absolute configuration of 1 was determined by time-dependent density functional theory electronic circular dichroism, specific optical rotation, and NMR calculations. Compounds 1 and 2 showed cytotoxicity towards HepG2, MCF-7, and SK-Mel2 carcinoma cells, with IC₅₀ values ranging from 48.6 to 96.5 µM. Compounds 1, 2, 4-6 displayed NO inhibitory effects in LPS-stimulated BV2 cells, with IC₅₀ values in a range from 24.2 to 76.5 µM. Compound 2 further inhibited PGE₂ overproduction, with an IC₅₀ value of 25.3 µM. The inhibitory effects of 2 towards NO and PGE₂ overproduction were found to have a close relationship with its suppression of iNOS and COX-2 protein expression, respectively.