New derivatives of nonactic and homononactic acids from Bacillus pumilus derived from Breynia fruticosa

Abstract

Six new nonactic and homononactic acid derivatives, ethyl homononactate (1), ethyl nonactate (2), homononactyl homononactate (6), ethyl homononactyl nonactate (7), ethyl homononactyl homononactate (8), and ethyl nonactyl nonactate (9), as well as four known compounds, homononactic acid (3), nonactic acid (4), homononactyl nonactate (5), and bishomononactic acid (10), were isolated from culture broth of Bacillus pumilus derived from Breynia fruticosa. The structures of new compounds were elucidated by spectroscopic analysis and chemical methods. The optical purities of 1-6 were determined by HPLC/MS after treatment with L-phenylalanine methyl ester. The dimeric compounds 5-9 showed weak cytotoxic activities against five human cancer cell lines (IC50 19-100 μg/ml).

Keywords: Bacillus pumilus; Breynia fruticosa; Cytotoxic activity; Homononactic acid derivatives; Nonactic acid derivatives.