Extraction, Identification and Antioxidative Properties of the Flavonoid-Rich Fractions from Leaves and Flowers of Cassia iangustifolia/i

摘要

Flavonoids identification, total flavonoids content and antioxidant activity of the extracts from the leaves as well as flowers of Cassia angustifolia were determined. Five different extraction techniques were used for the extraction of flavonoids from leaves and flowers. Total flavonoid contents (TFC) in the extracts were determined by UV-visible spectrophotometry. Individual flavonoids were identified and quantified by high-performance liquid chromatography coupled with photodiode array detection and electrospray ioniza- tion tandem mass spectrometry (HPLC-PDA-ESI-MS). It has been examined that aqueous ethanol (70%) fractions of C. angustifolia flowers and leaves are highly rich in flavonoids and microwave extraction is the best method for the extraction of individual flavanoid constituents (1 - 9) as well as total flavonoid contents. It was also found that compound 8 was absent in the leaves and compounds 2 and 5 could not be identified. The extracts of C. angustifolia flowers and leaves show strong antioxidant activity.