Antibacterial Evaluation of Piperidine Alkaloids from Cassia siamea Lam

Abstract

Bioassay directed isolation of the EtOAc extract from a chinese folk herb Cassia siamea Lam resulted in the purification of a new piperidine alkaloid (-)-(2R,3R,6R)-7-hydroxyspectaline (1), as well as a known analogue, (-)-(2R,3R,6R)-iso-6-spectaline (2). The structure of 1 was determined by extensive 1D and 2D NMR and MS data analyses. Compound 1 was isolated during a drug discovery program aimed at identifying new antibacterial leads from a prefractionated natural product library. Antibacterial study showed that both compounds are potent antimicrobial agents with MIC values range of 12.5-50 μg/mL against methicillinresistant Staphylococcus aureus and S. epidermidis, respectively.