Characterization of 2-Epicastasterone from Immature Seeds of Phaseolus vulgaris

摘要

Brassinosteroids (BRs), steroidal plant hormones, regulate diverse phenomenon in the growth and differentiation of plants. Among naturally-occurring BRs, castasterone (CS) has been identified as the most abundant BR in the plant kingdom, one which strongly regulates the overall development of plants, especially vegetatively growing plants. We have previously reported that immature seeds of Phaseolus vulgaris contain CS and a number of unknown BRs showing the same MS spectrum as that of CS with different retention times on GC and HPLC, suggesting that the unknown BRs are isomers of CS (Fig. 1). This prompted us to investigate the chemical structure of the unknown CS isomers, and lead to our identification of a new naturally-occurring BR, 2-epi-castasterone (2-epiCS) from immature seeds of P. vulgaris. Herein, we report elucidation of the structure and biological activity of 2-epiCS.