PHYSICOCHEMICAL AND PHYTOCHEMICAL ANALYSIS, ANTIOXIDANT AND ANTIMICROBIAL EVALUATION OF AERIAL PARTS OF JATROPHA SPINOSA, JATROPHA VARIEGATA AND EUPHORBIA MILII

Abstract

Yemen is renowned for its rich biodiversity, particularly its medicinal flora, which includes numerous endemic species of significant therapeutic value. This study aims to investigate the physicochemical and phytochemical properties of the aerial parts of Jatropha spinosa, Jatropha variegata, and Euphorbia milii, and evaluate their antioxidant and antimicrobial activities. Standard methodologies were used. Physicochemical parameters such as ash value, extractive value and moisture content were evaluated and phytochemicals like phenolics, flavonoids, tannins, terpenes, sterols and carbohydrates were determined in the studied plants. The total phenolic content in the 80% methanolic extracts were 128.12, 63.70, and 50.54 mg GAE/g for Euphorbia milii, Jatropha variegata and Jatropha spinosa, respectively. Antioxidant activity was evaluated using the in vitro DPPH assay. The IC₅₀ values of the methanolic extract of Jatropha spinosa, Jatropha variegata, Euphorbia milii, and the standard quercetin were 100.71 ± 0.43, 54.62 ± 0.63, 12.56 ± 0.34, and 2.37 ± 0.23 μg/mL, respectively. Among the studied extracts, Euphorbia milii exhibited the highest antioxidant activity, when compared with the standard quercetin. The antimicrobial activity was assessed using the agar well diffusion method. Methanolic extracts at concentrations of 250 mg/ml showed the highest antimicrobial activity against Staphylococcus aureus, with Euphorbia milii, followed by Jatropha variegata and Jatropha spinosa, producing inhibition zone diameters of 22.13 mm, 20.22 mm, and 17.43 mm, respectively. Against Pseudomonas aeruginosa, the inhibition zones were 20.22 mm for Euphorbia milii, 18.97 mm for Jatropha variegata, and 17.77 mm for Jatropha spinosa. Similarly, against Proteus mirabilis, inhibition zones were 18.32 mm, 17.54 mm, and 15.23 mm for Euphorbia milii, Jatropha variegata, and Jatropha spinosa, respectively. For Candida albicans, the inhibition zones were 19.44 mm for Euphorbia milii, 16.54 mm for Jatropha variegata, and 16.55 mm for Jatropha spinosa. The above results indicate that the studied plants, especially Euphorbia milii, may be good sources of antioxidants and antimicrobials.