Abstract Euphorbia abyssinica (Camel Slipper plant) is an important medicinal herb in East African traditional medicine, reputed for treating inflammatory, infectious, and dermatological conditions. While its biological activities are attributed to various secondary metabolites, a detailed phytochemical profile of its phenolic fraction remains underexplored. This study aimed to systematically extract, characterize, and evaluate the antioxidant potential of phenolic compounds from E. abyssinica leaves. An optimized ultrasonic-assisted extraction using a hydroethanolic solvent (70:30 ethanol/water) at pH 3 was employed. The phenolic composition was analyzed via Reverse-Phase High-Performance Liquid Chromatography with Photodiode Array detection (RP-HPLC-PDA). Total phenolic content (TPC) was quantified using the Folin-Ciocalteu assay, and in vitro antioxidant activity was assessed via the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, with results expressed as Gallic Acid Equivalents (GAE) and efficient concentration (EC). HPLC analysis identified and quantified five major phenolics: chlorogenic acid (45.9 µg/mL), kaempferol (9.18 µg/mL), caffeic acid (7.25 µg/mL), vanillic acid (3.81 µg/mL), and syringic acid (3.77 µg/mL). The extract exhibited a high TPC of 79.33 mg GAE/100 mL. It demonstrated potent DPPH radical scavenging activity, with inhibition rates up to 77%, and an EC range of 10.65–11.55 mg GAE/100 mL. The results confirm that E. abyssinica leaves are a rich source of bioactive phenolics, with chlorogenic acid as the dominant constituent. The strong correlation between TPC and antioxidant activity provides a scientific basis for the plant's ethnomedicinal uses in managing oxidative stress-related pathologies and supports its potential for development into standardized nutraceutical or cosmetic products.
ALALLAN et al. (Fri,) studied this question.