Comparative In Vitro Antioxidant Activities, Phenolic and Flavonoid Profiles of Different Morphological Parts of Commiphora africana (A. Rich.) Engl. (Burseraceae)

Abstract

Commiphora africana (A. Rich.) Engl. is widely used in African traditional medicine for managing oxidative stress-related disorders, but scientific validation of this part-specific use remains limited. This study evaluated and compared the antioxidant activities and total phenolic and flavonoid contents of leaf, stem bark, and root bark extracts of C. africana. Powdered plant materials were macerated in 80% aqueous ethanol for 48 h. Antioxidant capacity was assessed using DPPH, hydrogen peroxide (H₂O₂), phosphomolybdenum, and ferric reducing antioxidant power (FRAP) assays, while total phenolic and flavonoid contents were quantified by the Folin–Ciocalteu and aluminum chloride methods. All extracts showed concentration-dependent antioxidant activity. Initial DPPH screening gave IC₅₀ values of 26.90 ± 0.004 (leaf), 58.27 ± 0.006 (stem bark), and 39.34 ± 0.003 μg/mL (root bark), versus 6.43 ± 0.004 μg/mL for ascorbic acid. In extended testing, stem bark outperformed leaf in H₂O₂ scavenging (155.26 vs. 325.43 μg/mL), phosphomolybdenum reduction (1224.25 vs. 1682.33 μg/mL), and FRAP (658.56 vs. 942.17 μg/mL). Total phenolic content was highest in leaf (2.17 mg GAE/g dw); total flavonoid content was highest in stem bark (0.85 mg QE/g dw); all pairwise differences were significant (p < 0.05). The findings demonstrate that the antioxidant activity of Commiphora africana varies among plant parts, with the leaf exhibiting the highest phenolic content and strongest DPPH radical-scavenging activity, while the stem bark showed superior hydrogen peroxide scavenging and reducing power.