Antioxidant, diuretic activities and polyphenol content of Stereospermum kunthianum Cham. (Bignoniaceae)

Abstract

Stereospermum kunthianum was used for biological and phytochemical investigations. In biological studies, antioxidant activities were investigated with water, methanol and aqueous acetone extracts. Furthermore, the xanthine oxidase inhibitory activity and the diuretic activity of an aqueous acetone extract were evaluated. In the phytochemical investigations, the flavonoids and polyphenols were quantified spectrophotometrically in all extracts followed by high-performance liquid chromatography-mass spectrometry (HPLC–MS) analysis of an aqueous acetone extract. The 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing/antioxidant power (FRAP) and 2,2′-azinobis (3-ethylbenzoline-6-sulphonate (ABTS) methods have shown that the aqueous acetone extract presents the best antioxidant activities. This aqueous acetone extract was further proven to have interesting xanthine oxidase inhibitory activity, but only a weak diuretic activity. This aqueous acetone extract also possessed the highest phenolic and flavonoid contents. HPLC–MS analysis allowed identifying and quantifying, rutin, isoquercitrin, quercetin, hyperoside, quercitrin and luteolin and the glycosides of ferulic, sinapic p-coumaric acids and kaempferol, apigenin in aqueous-acetone extract.

Keywords:

• Stereospermum kunthianum
• antioxidant activity
• diuretic activity
• flavonoid and polyphenol
• HPLC–MS

Acknowledgements

We are grateful to the International Atomic Energy Agency for providing the facilities through the technical cooperation project BKF 5002. We are grateful to the Agence universitaire de la Francophonie through which the Doctoral Fellowship ‘EUGEN IONESCU’ allowed us to perform the HPLC–MS analysis and the diuretic activity studies in Medicine and Pharmacy University ‘Iuliu Hatieganu’.