Seed Maturity and Extraction Solvent Shape the Antioxidant and In Vivo Anti-Inflammatory Activities of Citrullus colocynthis (L.) Schrad. Extracts: Implications for Dermo-Functional Use

Abstract

Citrullus colocynthis (L.) Schrad. (Cucurbitaceae) is a medicinal plant, renowned since antiquity, widely used in traditional medicine for the management of metabolic and inflammatory disorders: seed extracts particularly are reported for the management of rheumatoid arthritis, articular inflammation and skin wound recovery. Our aim was to comparatively evaluate the antioxidant and anti-inflammatory activities of aqueous and oily extracts obtained from mature and immature seeds, and to preliminarily assess their dermal tolerance and protective effects against induced inflammation and UV damage. Antioxidant activity was investigated in vitro using β-carotene bleaching and ferric reducing antioxidant power (FRAP) assays, whereas anti-inflammatory activity and anti-irritation effects were evaluated in vivo in a mouse model using the xylene-induced ear edema and the UV-induced skin irritation test. Oily extracts from both maturation stages showed marked inhibition of β-carotene oxidation, while the aqueous extract of immature seeds exhibited the highest ferric reducing capacity; on the other hand, fixed oils demonstrated a significantly greater inhibitory effect on oedema, suggesting a higher efficacy in modulating acute inflammatory responses. Results showed how C. colocynthis seed maturity and extraction solvent influence the bioactive potential of these ingredients for phytotherapeutic and dermo-functional applications, supporting a possible use against wrinkle formation and UV-induced skin alterations.