Antimicrobial, antioxidant and anti-inflammatory activities of the root extracts and fractions of Terminalia avicennioides Guill. and Perr.

Abstract Background Infectious diseases remain a major source of death and sickness globally. Their management entails use of antimicrobials. However, emergence of microbial resistance to these agents is on the increase. Inflammation and oxidative stress also accompany disease states. Newer agents to counter microbes, inflammation and oxidative stress are needed. Terminalia avicennioides Guill and Perr. is regularly exploited as a traditional remedy to numerous complaints, comprising infections, inflammation and enhancement of well-being. This study was intended to examine the effects of the root extracts and fractions of T. avicennioides against select bacteria and fungi as well as their anti-inflammatory and antioxidant potentials. Antimicrobial, anti-inflammatory and antioxidant assessments were conducted with broth microdilution technique, lipoxygenase and 2,2-diphenyl-1-picryhydrazyl (DPPH) assays, respectively. Results All the bacteria displayed varying susceptibility to the different extracts. The extracts caused good antibacterial activity towards Staphylococcus aureus, Salmonella typhimurium, Stenotrophomonas maltophilis, Enterobacter cloaca, Klebsiella pneumoniae, Echinococcus faecalis and Escherichia coli, but moderate for Proteus mirabilis and Pseudomonas aeruginosa. Antifungal action varied from good to moderate against Fusarium spp, moderate against Aspergillus niger but inactive against Candida albicans. Anti-inflammatory and antioxidant activities were dose-dependent, recording robust activity at higher concentrations. The n-butanol fraction manifested the highest anti-inflammatory and antioxidant activities, then ethylacetate while methanol extract showed better activities among hot and cold water extracts. Conclusions The analysis of the biological activities of T. avicennioides root extracts and fractions revealed encouraging antibacterial, antioxidant and anti-inflammatory activities, which were dose reliant. The different extracts and fractions displayed variable grades of activity. The plant showed good antibacterial but weak antifungal action. These activities could be credited to polyphenols and other plant constituents. This report may explain some of the traditional medicinal uses of the plant and could open the door for further studies in search of newer compounds against microbial organisms, inflammation and/or oxidative stress