Identification and quantification of polyphenols from Cassia auriculata L. leaf, flower and flower bud using UPLC-QqQ-MS/MS

Cassia auriculata is an Ayurvedic medicinal herb, traditionally indicated for diabetes and hyperlipidemia. Several works have demonstrated its antioxidant, antidiabetic and anti-hyperlipidemic activity in vivo and in vitro. Nevertheless, only a few works have investigated its phytochemical composition, and specifically, the polyphenolic composition of the various plant parts that are traditionally used. In this work, the polyphenolic composition of C. auriculata leaves, flowers and flower buds were evaluated using UPLC-QqQ-MS/MS. Our results demonstrated the polyphenolic profile of C. auriculata plant parts. A total of five benzoic acids, four hydroxycinnamic acids, three flavonoids and two other phenolic compounds were identified and quantified. Our results show that in C. auriculata leaves, flavonoids were most abundant (4204 µg/g DW), while in flowers benzoic acids were the most prominent (3924 µg/g DW). Total benzoic acid contents ranged from 1580 to 3924 µg/g DW in leaf and flower, respectively. Hydroxycinnamic acids ranged from 404 µg/g DW in flower buds to 2623 µg/g DW in leaves. Flavonoids showed the highest contents in leaves, while the lowest levels were observed in flowers (2626 µg/g DW). The meaning of the results is discussed in light of the bioactivities of phenolic compounds, concomitant with C. auriculata reported medicinal bioactivities. To our knowledge, this is the first work to identify and quantify polyphenolic compounds in flower and bud of C. auriculata.