Evaluation Of Phytochemical and Antioxidant Activities of Daphne Gnidium

Unit in Applied Chemistry, Faculty of Sciences and Technique, Abdelmalek Essaadi University, Al Hoceima, 32003, Morocco

^* Corresponding author: kamalelyousfi1985@gmail.com

Abstract

This study aimed to quantify the phenolic and flavonoid contents of Daphne gnidium leaf extracts and evaluate their antioxidant properties. Daphne gnidium, a species from the Thymelaeaceae family, was extracted using methanol and ethyl acetate as solvents through two methods: sonication and Soxhlet extraction. The polyphenol and flavonoid contents were determined using spectrophotometric assays and were found to vary significantly depending on the extraction method. The sonicated extracts yielded between 67.57 and 70.12 µg gallic acid equivalents (GAE) per 100 mg of dry weight, while Soxhlet extracts ranged from 68.53 to 87.11 µg GAE/100 mg. Similarly, total flavonoid content ranged from 3.63 to 4.93 µg quercetin equivalents (QE) per 100 mg in sonicated extracts, and from 4.14 to 4.72 µg QE/100 mg in Soxhlet extracts. The antioxidant activity was evaluated using the DPPH radical scavenging assay and the β- carotene bleaching method. The extracts showed strong antioxidant potential, with IC₅₀ values in the DPPH assay ranging from 0.42 to 1.60 µg/mL, and an IC₅₀ of 0.815 ± 0.007 mg/mL in the β-carotene bleaching assay. Notably, the ethyl acetate extract obtained via Soxhlet and the methanolic extract obtained via sonication exhibited the highest antioxidant activities. Also, the two extracts tested, the Soxhlet extraction by ethyl acetate and the methanolic extract by sonication gave the most active sample of Daphne gnidium extracts with are more active than the reference extract.