Structures and biological activities of typicosides A1, A 2, B1, C1 and C2, triterpene glycosides from the sea cucumber Actinocucumis typica

Abstract

Five new minor triterpene glycosides, typicosides A1 (1), A 2 (2), B1 (3), C1 (4) and C2 (5), along with two known glycosides, intercedenside A and holothurin B3, have been isolated from the sea cucumber Actinocucumis typica. Structures of the glycosides were elucidated by 2D NMR spectroscopy and MS. Glycosides 1-5 are linear mono- and disulfated tetraosides differing from each other in both aglycone structures and monosaccharide composition of the carbohydrate chains. Typicosides A1 (1) and A2 (2) have identical monosulfated carbohydrate moieties with a xylose residue as the third monosaccharide unit and differ from each other in aglycon structures. Typicoside B1 (3) has glucose as the third monosaccharide residue. Typicosides C1 (4) and C2 (5) contain the same disulfated carbohydrate chains and differ from each other in structures of aglycone side chains. Antifungal activity of glycosides 1-5 against three species of fungi along with cytotoxic activity against mouse spleen lymphocytes and mouse Ehrlich carcinoma cells (ascite form), as well as hemolytic activities against mouse erythrocytes have been studied. All new glycosides, except for typicoside C1 (4), containing a hydroxy-group in the aglycone side chain, demonstrate rather strong hemolytic and cytotoxic activities.