Abstract

Background: Ethnomedicinal practices typically employ botanical medicines as complex mixtures of two or more plants whose net bioactivity is the culmination of its phytochemical additivity or phytochemical synergy or phytochemical antagonism among discreet phytochemical entities. The aqueous co-extract mixture of Combretum molle (stem bark) and Xylopia aethiopica (fruit) is an example of this practice where the two botanicals are popularly co-used ethnomedicinally for the promotion of healthy wound healing.

Aim: To evaluate the potential phytochemical synergy of the combined methanol extracts of Combretum molle (stem bark) and Xylopia aethiopica (fruit) and to examine the effect of this co-extract on the relative anti-inflammation efficacy in vivo, on the relative attenuation of microbial growth in vitro and on the relative mitigation of oxidative stress in vitro.

Methods and Materials: The antioxidant effect of the combination was assessed through the DPPH radical scavenging activity in vitro. Broth dilution evaluations of anti-microbial susceptibility was taken as the in vitro anti-microbial response. Oral administration of co-extract to suppress the carrageenan-induced foot oedema in 7-day chicks was chosen for the in vivo assessment of the anti-inflammatory response.

Results: Although the phenolic content of Combretum molle (stem bark) was 1.6-fold higher than that of the Combretum molle (stem bark) and Xylopia aethiopica (fruit) co-extract, its DPPH radical scavenging activity was 38.2-fold lower leading to the conclusion that the co-extract yielded robust synergistic attenuation of oxidative stress through DPPH radical scavenging activities in vitro. Co-extracts produced a synergistic inhibition of fungal cell growth (2-fold higher inhibition over individual extracts) in the two fungal species (Candida albicans and Taenia corporis) in vitro. Not only did the co-extract efficacy outperformed the efficacy of individual extracts at the dose-response endpoints of the carrageenan-induced inflammation in 7-day old chicks but it also matched the efficacy of the control drug Diclofenac.

Conclusion: Clinically relevant phytochemical combinations from ethnomedicinal sources acting synergistically can exert net potent biological effects of medicinal importance. The Combretum molle (stem bark) and Xylopia aethiopica (fruit) co-extract ethnomedicinal wound care have implications for healthy wound healing and can be brought forward into the clinical and public health realms for translational impact.

Keywords: Combretum molle, Xylopia aethiopica, anti-microbial, antioxidant, anti-inflammation, phytochemical synergy