Phytochemical characterization and antioxidant potential of the leaves of Calyptrochilum christyanum (Rchb.f.) Summerh. collected in Man, Western Côte d’Ivoire

Abstract

Calyptrochilum christyanum (Rchb.f.) Summerh. is an orchid species reported to be used in traditional medicine in Côte d’Ivoire, but its phytochemical composition and biological properties remain poorly documented. This study aimed to characterize the phytochemical profile and evaluate the antioxidant activity of aqueous and hydroethanolic leaf extracts of C. christyanum. Thin-layer chromatography (TLC) was used for phytochemical screening, while total phenolic compounds, flavonoids, and condensed tannins were quantified using colorimetric methods. Antioxidant activity was evaluated by TLC-DPPH bioautography and spectrophotometric DPPH assays. TLC revealed the presence of tannins, flavonoids, coumarins, and anthraquinone/anthrone derivatives. The aqueous extract exhibited the highest levels of total phenolic content (157.75 ± 3.89 mg GAE/g extract), flavonoids (87.53 ± 6.11 mg QE/g extract), and condensed tannins (17.35 ± 1.26 mg CE/g extract). However, the hydroethanolic extract showed stronger antioxidant activity (IC₅₀ = 0.197 mg/mL) than the aqueous extract (IC₅₀ = 0.739 mg/mL). These findings highlight C. christyanum leaves as a potential source of antioxidant phytochemicals.