Phytochemical Analysis and Investigation of the Antibacterial and Antioxidant Activities of Aristolochia albida Root Extracts

Introduction: The increasing prevalence of antibacterial resistance has led to the deliberate laborious exploration of plants for new potent drugs. Over the years, plants have served as rich reservoirs of medicinal components that are used for the management of various ailments because of the belief that they exhibit minimal side effects and improved efficacy than other synthetic counterparts.

Aim: The aim of this research is to evaluate the phytochemical content, antimicrobial and antioxidant activities of the root extracts of A. albida; a shrub that is commonly used in North Central Nigeria for the management of some microbial infections, snakebite, stomach ailments and pain.

Methods: The roots of A. albida were harvested, washed with clean water, dried, ground, and extracted with hexane, ethyl acetate, methanol and water using the Soxhlet extractor. The phytochemical screening which indicated the presence of alkaloids, anthraquinones, flavonoids, terpenes, cardiac glycosides and tannins was done using standard methods. The antimicrobial activity was tested using agar well diffusion technique against five human pathogens namely: Staphylococcus aureus, Escherichia coli, Salmonella typhi, Streptococcus pneumonae and Pseudomonas aeruginosa while the antioxidant activities were tested using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) method.

Results: All extracts showed the antibacterial activity against all test organisms at all concentrations used. At 50 mg/cm3, S. aureus showed high sensitivities with 23.00 mm, 20.50 mm, 22.00 mm and 18.50 mm diameter of zone of inhibition for hexane, ethyl acetate, methanol and water extracts respectively. The results obtained in this study indicated that the MICs of the four extracts were weak (12.50-200.0 mg/cm3) when compared to the MIC range of most commonly available antibiotics having a range of 0.015-0.107 mg/cm3. The extracts demonstrated minimum bactericidal concentration (MBC) range of 400-50 mg/cm3. All the extracts showed a DPPH scavenging activity which increased with increase in sample concentration. Among the solvents used, hexane extract gave the highest antioxidant activity, IC50 = 0.032 mg/cm3. Ethyl acetate and water extracts of A. albida had IC50 = 0.05 mg/cm3.

Conclusion: The results reported in this research work highlighted the potential use of A. albida extract as a source of phytochemicals with promising antimicrobial and antioxidant activities.