Isomeric phenylpropanoid from Stereospermum suaveolens (Roxb.) DC Growing in Bangladesh

Abstract

Plants have long been a crucial source of bioactive compounds for developing innovative therapeutics against various diseases. The research aimed to explore the natural compound composition of methanol extracts from the leaves and stem bark of Stereospermum suaveolens (Roxb.) DC (Family: Bignoniaceae) through repeated chromatographic separation and purification processes using silica gel. The phytochemical investigation led to the identification of two isomeric phenylpropanoids, namely 4-methoxy-cis-cinnamic acid (1) and 4-methoxy-trans-cinnamic acid (2). The chemical structures of these isolated compounds were determined through the data from ¹H-NMR, ¹³C-NMR, COSY, HSQC and HRMS, and were confirmed by comparing the results with published reports. Notably, this marks the first reported instance of the isolation of the isomeric 4-methoxycinnamic acid from any plant species so far.