Isolation of phytochemical constituents from Stevia rebaudiana (Bert.) and evaluation of their anticancer, antimicrobial and antioxidant properties via in vitro and in silico approaches

Abstract

The current study was designed to isolate and characterize some bioactive secondary metabolites by using repeated chromatographic and spectroscopic techniques, targeting their anticancer, antimicrobial, and antioxidant properties through <i>in vitro</i> and <i>in silico</i> approaches. Six compounds were isolated and analyzed by thin layer chromatographic technique and the compounds were identified as 5-<i>O</i>-caffeoyl quinic acid (<b>1</b>), syringin (<b>2</b>), luteolin (<b>3</b>), apigenin (<b>4</b>), jhanol (<b>5</b>), and jhanidiol (<b>6</b>) based on spectroscopic methods. The cytotoxic effect of each compound was dose-dependent, and compound <b>1</b> showed a higher anti-proliferative effect (IC₅₀ = 181.3 μg/ml) than other compounds (compound <b>2</b>, <b>4</b>, <b>5</b>, and <b>6</b>). Besides, compound <b>1</b> showed the most promising antibacterial activity with a zone of inhibition ranges from 12-15 mm against different strains compared to ciprofloxacin (14-22 mm). In contrast, compound <b>3</b> exerted the highest scavenging property against DPPH free radical. Finally, the <i>in vitro</i> bioactivities were also supported by molecular docking studies. The computational study demonstrated that the isolated compounds exerted stronger affinity compared to the standard drugs towards the binding sites of dihydrofolate reductase (DHFR), glutathione reductase, and urase oxidase.