Biologically Active Saponin from Seeds of Allium Ampeloprasum

Abstract

A novel oleanen type triterpenoid glycoside has been isolated from the butanolic extract of the seeds of Allium ampeloprasum. Its structure was elucidated as 3?O?{??D?glucopyranosyl?(1?6)?[??L?rhamnopyranosyl?(1?2)]???D?glucopyranosyl?(1?4)?[??D?glucopyranosyl?(1?2)]???D?xylopyranosyl}?2,16?dihydroxy?23,29?dihydroxymethylolean?11,13(18)?diene?28?oic acid on the basis of spectral evidences, i.e. FT?IR, ¹H NMR, ¹³C NMR and FAB?MS data. The isolated saponin was tested for its antimicrobial activity.  Significant results were obtained by evaluating the antibacterial activity by “Disc diffusion method” and antifungal activity by “Spore  dilution  method”.  Maximum  inhibition  was  recorded  in  gram  positive  bacterium? Streptococcus  pneumoniae,  while  complete  inhibition  on  the  growth  of  fungus?Alternaria alternata was observed at a concentration of  200  ?g/mL. The potency of the extract was quantitatively assessed by determining the minimum inhibitory concentration values against selected bacteria.  The minimum inhibitory concentration values were in agreement with antibacterial results where minimum value was recorded to be 23 ?g/mL for Streptococcus pneumonia.

Key Words: Allium ampeloprasum, Triterpenoid, Saponin, Antimicrobial activity.