Structural relationship among steroids from Sulawesi Tenggara’s sponge Clathria sp. and their radical scavenger activity

Four steroids were isolated and identified from the acetone extract of Clathria sp., namely clathruhoate or 3 β -(butiryloxymethyl)- A -nor-5α-cholestane ( 1 ), 3 β -(acetoxymethyl)- A -nor-5α-cholestane ( 2 ), 3 β -(hydroxymethyl)- A -nor-5α-cholestane ( 3 ), and 3 β -(hydroxymethyl)- A -nor-5α-cholest-15-ene ( 4 ). Isolation was carried out using chromatography techniques including Thin Layer Chromatography (TLC), vacuum liquid chromatography (VLC) and radial chromatography (RC) with silica gel as adsorbent and mixture of solvents as eluent. The Structure of isolated compounds was determined by spectroscopic methods i.e. FTIR, 1 H and 13 C NMR and also by comparing the spectroscopic data with similar data from references. The compounds isolated were evaluated for biological activity against a radical agent (DPPH radical). The relationship of the steroids showed that compound 3 is an oxidation product of compound 4 . Clathruhoate ( 1 ) is formed by esterification of compound 3 with buthanoic acid, and compound 2 is produced by esterification of compound 3 with acetic acid. The radical scavenger potential of the methanol extract and steroids from Clathria sp. can be summarized as follows: methanol extracts > compound 4 > compound 3 > compound 2 > compound 1.