Comparative Antioxidant and Antimicrobial Activities of Stem and Root Bark Extracts and Solvent Fractions of Securidaca longepedunculata

Securidaca longepedunculata Fresen is widely used in traditional medicine in northern Ghana, particularly the stem and root bark for treating various diseases. However, extensive root harvesting threatens the sustainability of the species. This study evaluated and compared the antioxidant and antimicrobial properties of the plant's stem and root bark extracts and fractions. Powdered stem and root bark samples were extracted with 70% ethanol and successively fractionated using chloroform, ethyl acetate, and butanol. Phytochemical screening, total phenolic content (TPC), total flavonoid content (TFC), total antioxidant capacity (TAC), DPPH radical scavenging activity, and antimicrobial assays were performed on all extracts and fractions. Phytochemical analyses revealed that both stem and root bark extracts contained similar phytochemicals. The stem bark extract showed higher antioxidant capacity (251.14 ± 1.66 mg AAE/g DW) than the root bark (245.38 ± 7.37 mg AAE/g DW), and a lower IC₅₀ value in the DPPH assay (0.343 ± 0.081 mg/mL vs 0.491 ± 0.131 mg/mL). Antimicrobial assays revealed broad-spectrum activity, with the stem bark extract demonstrating greater efficacy (activity score of 7 versus 2 for the root). Among the fractions, the Chloroform fractions exhibited the highest phenolic and flavonoid contents, as well as antioxidant and antimicrobial activity. The stem bark of S. longepedunculata exhibits superior antioxidant and antimicrobial activities compared to the root bark. These findings highlight the stem bark as a promising and more sustainable alternative for medicinal use. The findings also showed that solvent polarity affected the extraction and activity of the plant.