Sesquiterpene and Sorbicillinoid Glycosides from the Endophytic Fungus Trichoderma longibrachiatum EN-586 Derived from the Marine Red Alga Laurencia obtusa .

An unusual sesquiterpene glycoside trichoacorside A ( 1 ) and two novel sorbicillinoid glycosides sorbicillisides A ( 2 ) and B ( 3 ), together with a known compound sorbicillin ( 4 ), were isolated and identified from the culture extract of an endophytic fungus Trichoderma longibrachiatum EN-586, obtained from the marine red alga Laurencia obtusa . Trichoacorside A ( 1 ) is the first representative of a glucosamine-coupled acorane-type sesquiterpenoid. Their structures were elucidated based on detailed interpretation of NMR and mass spectroscopic data. The absolute configurations were determined by X-ray crystallographic analysis, chemical derivatization, and DP4+ probability analysis. The antimicrobial activities of compounds 1 - 4 against several human, aquatic, and plant pathogens were evaluated.