ISOLATION OF A NONSTEROIDAL CONTRAGESTATIVE AGENT FROM SRI-LANKAN MARINE RED-ALGA, GELIDIELLA-ACEROSA

This study reports the isolation of a non-steroidal contragestative ag ent from the Sri Lankan marine red alga, Gelidiella acerosa. One-hundr ed grams of MeOH-CH2Cl2 (1:1) crude extract of G. acerosa was initiall y partitioned into hexane, CH2Cl2 and EtOAc, respectively, using the m odified Kupchan scheme. At each separation step, all the resulting fra ctions were tested for contragestative effects in pregnant rats. The f ertility was assessed in terms of the number of viable implants follow ing oral administration of fractions (co-precipitated with polyvinylpy rrolidone), on day 1 through day 7 of pregnancy. The hexane fraction w ith highest activity was subjected to gel filtration through Sephadex LH-20, vacuum liquid chromatography over TLC-grade silica, two open-co lumn chromatography runs over silica gel (60-120 mesh), and HPLC to is olate the active component. Nuclear magnetic resonance and infrared sp ectroscopic analysis revealed that the contragestative agent of G. ace rosa is a sphingosine derivative. (C) 1996 Elsevier Science Inc.