Simultaneous determination of caffeic acid and vitexin contents in Thunbergia laurifolia leaf extracts collected from different provinces in Thailand by HPLC

Abstract

© Faculty of Pharmacy, Mahidol University (Thailand) 2018. Thunbergia laulifolia Lindl. (rang chuet) is a fast growing, perennial climbing vine in Acanthaceae family. Twelve T. laulifolia leaf samples were collected from different provinces in Thailand. All samples were identified by analysis of macroscopic and microscopic characteristics and chromatographic fingerprints compared with authentic sample. The simultaneous quantitative analysis of caffeic acid and vitexin was developed and validated using High Performance Liquid Chromatography (HPLC). The analytical method for these two compounds was developed with acceptable validation parameters. Good linearity ranges of caffeic acid and vitexin were 2 - 32 μg/mL. The repeatability and intermediate precision were shown to be precised with relative standard deviations of less than 5%. The average percentage recovery of caffeic acid and vitexin were 95.87% and 101.52% suggesting the acceptable accuracy. The content of caffeic acid and vitexin in T. laulifolia leaves collected from different provinces in Thailand analyzed by the validated HPLC method was in the ranges of 0.01 ± 0.00 to 0.28 ± 0.30 and 0.01 ± 0.00 to 0.07 ± 0.02 g/100 g of crude extract, respectively. The leaves collected from Chaiyaphum and Phitsanulok provinces significantly contained the highest caffeic acid and vitexin contents, respectively. The validated HPLC method is rapid, precise, reliable and sensitive for routine analysis of caffeic acid and vitexin contents in T. laulifolia leaf raw materials and its commercial products in the future.