Wound Healing Potential of Combined Extracts of Stem Bark and Leaves of Sphenocentrum Jollyanum: A Classical Factorial Design Model Approach

Stem bark, in combination with the leaves of Sphenocentrum jollyanum, is used for the management of wounds in the Southern part of Nigeria. The wound healing potential was determined by applying different concentrations of the prepared plant extracts, alone and in combination, to deep partial-thickness wounds on a rat model. Wound healing was measured on 15 days post-operation and compared with the controls. The percentage wound closure efficacy of the combined leaves and stem bark extracts were determined and compared statistically by 22 Factorial design model over 2, 8, and 15 post-operative days. Fluctuations in the wound surface pH were also measured over 15 days. All the extracts-treated wounds epithelized faster with dosedependent wound contraction, reaching statistically significant differences (p<0.01) compared with untreated wounds. The stem bark extract was about 50% more potent than the leaves extract. A significantly higher wound contraction effect of combined extracts was observed when compared with the individual extract effects. Also interesting was the <10 days complete epithelization observed in combined (200 mg equivalent) leaves and stem bark-treated wounds, which is shorter than 13 postoperative days in both 100 mg stem bark extract- and cicatrin-treated groups. However, there was no statistical evidence (*p<0.0) of interaction between the leaves and stem bark extracts; and improved activities of the combined extracts, in comparison with the individual extracts, were purely additive. The initial alkaline wound surface pH normalized to acidic pH within 8 and 12 post-operative days in extracts- and positive control-treated wounds. S. jollyanum extracts possess promising wound healing property. This study validated the primary folkloric use of the plant and aside from additive effect, empirical and statistical evidences showed that there was no basis for the claimed potency of combined leaves and stem as used by the traditional healers.

Keywords: Ethnomedicine, Factorial design, Sphenocentrum jollyanum, Wound contraction.