Chemical and pharmacological studies of the polar consituents of luffa echinata and luffa cylindrica

Abstract

The fruits of Luffa echinata /800 gm) were extracted with chloroform 13X48 hours) at room temperature. The chloroform extracts yielded a deep green solid mass (40 gm) on removal of the solvent. The chloroform extract was fractionated with nhexane. The n-hexane insoluble part gave a green solid Mass L /30 gm). On decolourization with activated charcoal Mass L yielded a yellowish solid mass (2S gm) which was noted as Mass L1• Mass L1 showed the presence of at least six compounds on TLC plates. Column chromatographic separation of Mass LIon silica gel with CC14 : EtOAc 11:1) as eluant gave one pure compound A1,a mixture of two compunds (A2 &: A3) and a fraction which on concentration gave a crystalline solid. /compound A4). Compound A2 and compound A3 were separated from the mixture by preparative TLC. The mother liquor on removal of compound A4 gave a solid mass, (Mass L2). Mass L2 on further chromatography gave two more pure compounds, compound AS and compound A6, Compound AI' A2,A3, A4 and extensive use of UV, IR, IH NMR, AS were characterized by 13C NMR and mass spectral analyses. The compounds are datiscacin(37)/a cucurbitacin-20- acetate ester darivative) ,(AI' yield 0;013%), cucurbitacin B(41), (A2, yield 0.266%), isocucurbitacin B(421, (A3, yield 0,109%),3- sitosterol glucoside(43l, (A4, yield 0.047%) and 2-0-3-Dglucopyranosyl cucurbitacin B(44), (AS' yield 0.936%). UV and IR spectra of compound A6 suggested it to be cucurbitacin S glucoside(4S), (A6, yield 0.043%) but remains to be confirmed. 123 The present investigation has led to the isolation of three more compounds namely datiscacin(37), 2-0-B-D-glucopyranosyl cucurbitacin B(44) and cucurbitacin S glucoside(45) besides cucurbitacin B(41),isocucurbitacin B(42)and a-sitosterol glucoside(43) from Luffa echinata. Of course the structure of cucurbitacin S glucoside requires to be more regorously established. The ethanol extract of the plant Luffa echinata shows potent -.~ activity against spasmogen induced contraction in gtil~~~~pig ileum, poor activity on guinea-pig atria and poor activity against oxytocin induced contraction in rat uterus.