Src tyrosine kinase inhibitory and antioxidant activity of Stevia rebaudiana Bertoni

Stevia rebaudiana Bertoni (Stevia) is a perennial herb of the Asteraceae family, a well-known source of the natural sweetener steviol glycosides. Isolation of the sweet compounds from Stevia generates large amounts of waste, which could be a rich source of many bioactive compounds. Previous studies have shown promising health benefits of Stevia against diabetes, obesity, hypertension, cancer, dental caries and microbial infections [ 1 ] [ 2 ]. Therefore, the aim of our study was to investigate the polyphenolic composition of the ethanolic extract of Stevia leaves and, for the first time, its ability to inhibit Src tyrosine kinase activity and scavenge NO free radicals. The total content of phenolic acid and flavonoids (5.06% and 1.36%, respectively) in Stevia leaves was determined spectrophotometrically. Eight hydroxycinnamic derivatives and thirteen flavonoids were identified in the ethanolic extract by LC-ESI-MS/MS. Caffeoylquinic acids were found to be the predominant constituents (7.62-55.21 mg/g). The ethanolic extract inhibited Src tyrosine kinase activity in the time-resolved fluorescence resonance energy transfer (TR-FRET) assay (IC 50 =213 μg/mL). It also showed a strong ability to scavenge NO radicals (IC 50 =67.58 μg/mL). Our study suggests that Stevia may be beneficial in cancer and other inflammation-related diseases, with chlorogenic acid and its derivatives making a substantial contribution. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany