Anti-inflammatory and cytotoxic assessment of flavonoids isolated from Viola odorata flowers with computer-guided docking study

Abstract

Abstract The therapeutic potential of plant-derived polyphenols has garnered significant attention due to their roles in modulating inflammation and cancer progression. Viola odorata (V. odorata), traditionally used in herbal medicine, is known for its bioactive constituents, yet comprehensive profiling of its floral phytochemicals—particularly phenolic acids, flavonoids, and anthocyanins—remains limited. This study was pharmacologically designed to investigate the detailed phytochemical composition of V. odorata flowers and evaluate their anti-inflammatory and anticancer activities, aiming to identify novel natural agents for therapeutic development. Methanolic extracts of V. odorata flowers were analyzed for total phenolics, flavonoids, and anthocyanins using spectrophotometric methods. HPLC and UPLC/ESI–MS techniques were employed to identify and quantify individual compounds. Structural elucidation of isolated flavonoids was performed using advanced spectroscopic techniques. The anti-inflammatory and cytotoxic effects of the extract and isolated flavonoids were assessed in vitro using hepatocellular carcinoma (HepG2), human colonic epithelial (Caco-2), and colorectal carcinoma (HTC-116) cell lines. Molecular dynamics simulations were conducted to explore the interactions underlying the observed bioactivities. The methanolic extract contained 81.34 ± 0.17 mg GAE/g of total phenolics, 69.45 ± 0.24 mg CE/g of flavonoids, and 92.43 mg cyanidin-3-glucoside/100 g of anthocyanins. HPLC analysis revealed twelve phenolic acids and ten flavonoids, with gentisic acid (391.37 μg/g), apigenin-7-glucoside (417.22 μg/g), catechin (372.56 μg/g), and rutin (262.73 μg/g) being predominant. UPLC/ESI–MS identified 8 phenolic acids and derivatives, 3 flavonols, 4 flavones, 14 flavonoid glycosides, and 5 anthocyanins derived from cyanidin, delphinidin, and petunidin. Three flavonoids—5,7-dihydroxy-3,6-dimethoxyflavone, luteolin 7-O-glucoside, and kaempferol 3-O-rutinoside—were isolated and structurally characterized. The extract and isolated compounds exhibited dose-dependent cytotoxicity and anti-inflammatory effects across all tested cell lines. Molecular dynamics studies supported the observed inhibitory mechanisms. This study highlights the rich polyphenolic profile of V. odorata flowers and their promising anti-inflammatory and anticancer properties. The correlation between phytochemical composition and pharmacological activity underscores the therapeutic potential of V. odorata as a source of bioactive compounds for drug development.