Two New Cytotoxic Nonsulfated Pentasaccharide Holostane (=20‐Hydroxylanostan‐18‐oic Acid γ‐Lactone) Glycosides from the Sea Cucumber Holothuria grisea

Abstract

AbstractTwo new lanostane‐type nonsulfated pentasaccharide triterpene glycosides, 17‐dehydroxyholothurinoside A (1) and griseaside A (2), were isolated from the sea cucumber Holothuria grisea. Their structures were elucidated by spectroscopic methods, including 2D‐NMR and MS experiments, as well as chemical evidence. Compounds 1 and 2 possess the same pentasaccharide moieties but differ slightly in their side chains of the holostane‐type triterpene aglycone. The structures of the two new glycosides were established as (3β,12α)‐22,25‐epoxy‐3‐{(O‐β‐D‐glucopyranosyl‐(1→4)‐O‐[O‐3‐O‐methyl‐β‐D‐glucopyranosyl‐(1→3)‐O‐β‐D‐glucopyranosyl‐(1→4)‐6‐deoxy‐β‐D‐glucopyranosyl‐(1→2)]‐β‐D‐xylopyranosyl)oxy}‐12,20‐dihydroxylanost‐9(11)‐en‐18‐oic acid γ‐lactone (1) and (3β,12α)‐3‐{(O‐β‐D‐glucopyranosyl‐(1→4)‐O‐[O‐3‐O‐methyl‐β‐D‐glucopyranosyl‐(1→3)‐O‐β‐D‐glucopyranosyl‐(1→4)‐6‐deoxy‐β‐D‐glucopyranosyl‐(1→2)]‐β‐D‐xylopyranosyl)oxy}‐12,20,22‐trihydroxylanost‐9(11)‐en‐18‐oic acid γ‐lactone (2). The 17‐dehydroxyholothurinoside A (1) and griseaside A (2) exhibited significant cytotoxicity against HL‐60, BEL‐7402, Molt‐4, and A‐549 cancer cell lines.