Chemical Constituents From the Marine Microalgae Thraustochytrium pachydermum

Objectives Isolation, structure determination, and antimicrobial activities evaluation of compounds from the methanol extract of the marine microalga Thraustochytrium pachydermumTSL10.Methods Using chromatographic methods to isolate compounds from the methanol extract of the T pachydermum. The chemical structures were elucidated by analyses of HR-ESI-MS and NMR spectral data. The antimicrobial activities of compounds were evaluated using the dilution turbidimetric broth method as the standard protocol published by the Clinical and Laboratory Standard Institute.Results One new sterol, (24R)-ergosta-7,22-diene-3β,5α,9α-triol (1), and 16 known compounds, ergosta-7,22-diene-3β,5α-diol (2), cerevisterol (3), (22E,24S)-5α,6α-epoxy-ergosta-8(9),22-diene-3β,7α-diol (4), ergosterol (5), 5α,8α-epidioxyergosta-6,22-diene-3β-ol (6), linoleic acid (7), 4-((9Z,12Z)-octadeca-9,12-dienoyloxy)butanoic acid (8), 1-linoleoyl-sn-glycero-3-phosphocholine (9), cibotiglycerol (10), gingerglycolipid B (11), oleic acid (12), 4-((9Z)-octadec-9-enoyloxy)butanoic acid (13), (2S)-1-O-(9Z)-octadec-9-enoyl)-3-O-(6-sulfo-D-quinovopyranosyl)glycerol (14), 6′-O-linoleylsucrose (15), gingerglycolipid C (16), and (S)-3-stearoyl-sn-glycerol (17) were identified from the marine microalga Thraustochytrium pachydermumTSL10. Sterols 1–6were found to exhibit significant antimicrobial activities on Gram-( + ) bacteria (Enterococcus faecalisATCC29212, Staphylococcus aureusATCC25923, and Bacillus cereusATCC14579) and the yeast (Candida albicansATCC10231) with MIC values ranging from 32 to 256 µg/mL.Conclusions The results suggested sterols 1–6could be potential antimicrobial agents against Gram-( + ) bacteria.