Antifungal Steroidal Glycosides from the Patagonian StarfishAnasteriasminuta:  Structure−Activity Correlations

Abstract

Two new sulfated steroidal hexaglycosides, anasterosides A (2) and B (3), along with the known versicoside A (1) have been isolated from the Patagonian starfish Anasterias minuta. Their structures have been elucidated by spectroscopic analysis (NMR and FABMS) and chemical transformations. Compounds 1 and 2 and the synthetic pentaglycoside 1b derived from versicoside A showed antifungal activity against the plant pathogenic fungus Cladosporium cucumerinum. Desulfation of hexaglycoside 1 rendered a totally inactive saponin.

Asterosaponin 1 induces endoplasmic reticulum stress-associated apoptosis in A549 human lung cancer cells

“…Asterosaponin is a new class of steroidal glycosides extracted and isolated from starfish and responsible for their general toxicity (4). Diverse pharmacological effects induced by asterosaponin and its analogues have been reported, including antibacterial, antiviral, antitumor and antifungal activities (5)(6)(7).…”

Structural Determination of Saponins Extracted from Starfish by Fast Atom Bombardment Collision-Induced Dissociation Mass Spectrometry

“…1,2 Some saponins have properties of hemolysis, bitterness, complex formation with cholesterol, and fish poisons. [3][4][5][6] Saponins consist of sugar moieties linked to aglycone, which are classified into triterpenoid and steroid types, sugars are linked to the aglycone generally through an ester or an ether linkage at one or two sites. [7][8][9] Saponins are found predominantly in the secondary metabolites of starfish and exist as complex mixtures in minute amounts.…”

Asterosaponins Isolated from the Starfish Asterias amurensis

“…[8][9][10][11][12] The starfish saponins can be categorized into three main groups: asterosaponins possessing a sulfated steroidal moiety; steroidal cyclic glycosides, which to date have only been found in two species of the genus Echinaster; and polyhydroxysteroidal saponins. 8) Due to the widespread interest in their biological and structural significance, we have undertaken structural studies on the saponins of A. amurensis.…”

“…8) Due to the widespread interest in their biological and structural significance, we have undertaken structural studies on the saponins of A. amurensis. Our recent investigation on the n-BuOH soluble fraction of A. amurensis resulted in the isolation of three new asterosaponins 1-3, and four known saponins, thornasteroside A (4), [12][13][14][15][16][17][18] versicoside A (5), 18,19) anasteroside B (6), 11) and asteronyl pentaglycoside sulfate (7). 15,20) Although the chemical structures of asterosaponins 4-7 have been already determined using hydrolyzed molecules, there are few reports on the full NMR assignment for undegraded saponins.…”