Caractérisation phytochimique et évaluation de la capacité antioxydante de Calendula officinalis L.

Abstract

Medicinal plants have been used for centuries for their therapeutic properties. Rich in bioactive compounds, they offer natural treatment options for various pathologies. This study aims to valorize Calendula officinalis L. by characterizing its phenolic compounds and evaluating the in vitro antioxidant activity of its aerial parts. Two extraction methods were performed using maceration with different solvents: water and ethanol. Qualitative phytochemical analyses were conducted using colorimetric reactions, and the total phenolic content, condensed tannins, and hydrolysable tannins were quantified. Additionally, in vitro antioxidant activity was assessed using multiple methods: DPPH, ABTS, FRAP, and CAT. The results revealed significantly higher levels of total phenolics and catechic tannins in the hydroethanolic extract (3.293 mg GAE/g lyophilizate and 0.082 mg CE/g lyophilizate, respectively) compared to the aqueous extract (0.26 mg GAE/g lyophilizate and 0.014 mg CE/g lyophilizate). However, hydrolysable tannins were more abundant in the aqueous extract (1.203 mg TAE/g lyophilizate) than in the hydroethanolic extract (0.121 mg TAE/g lyophilizate). Regarding antioxidant activity, the aqueous lyophilizate of C. officinalis exhibited lower IC50 values for DPPH and ABTS radicals (2.921 mg/mL and 2.835 mg/mL, respectively) compared to the hydroethanolic lyophilizate (5.942 mg/mL and 3.139 mg/mL, respectively). Meanwhile, the total antioxidant capacity (FRAP and CAT) was nearly comparable for both extracts. The findings confirm that Calendula officinalis L. could serve as a valuable source of phenolic compounds with potential applications as an antioxidant agent. This capacity may be key to developing novel therapeutic strategies.