Formulation and efficacy assessment of a polyherbal wound healing formula from Heliotropium indicum and Nephrolepis biserrata

Background: Heliotropium indicum and Nephrolepis biserrata denoted herewith as H and F are common medicinal plants used in folk medicine for the treatment of many disease conditions including wounds in most African countries such as Ghana. Previous separate preliminary studies on these two herbs have shown that they have wound healing abilities. However, their combined effects with respect to wound healing remain unknown. Relatedly, many studies have identified diverse phyto-compounds in the leaves of these two medicinal plants which are suspected to possess anti-oxidant and free radical scavenging properties. Objective: The present study describes development of a polyherbal wound healing formulation from leaves of H and F and further assessed their wound healing effects by using both in vivo and in vitro wound healing models. Materials and Methods: After collection of H and F leaves and confirmation of their identity, ethanol was used to extract phyto-compounds from the dried leaves of H and F. The crude ethanol extract of both H and F were subjected to phytochemical screening using standard methods. Subsequently, anti-oxidant and free radical scavenging properties of the crude extracts were assessed. By using weight: weight (W/W) proportions, the polyherbal formula was prepared. Excision wound model was used to test the wound healing effects of the polyherbal formula. Wound contraction and wounding days were used as endpoints to assess the degree of wound healing effects of the polyherbal formula. Results: Extract of F exhibited antioxidant activity with an IC50 value of 324.1 μg/mL in the DPPH radical scavenging method, 745.6 μg/mL in the NOS assay, and 806.4 μg/mL in the ferric reducing assay. On the other hand, extract of H exhibited antioxidant activity with an IC50 value of 301.1 in the DPPH radical scavenging method, 350.1 μg/mL in the NOS assay, and 180.5 μg/mL in the ferric reducing assay. The amount of total phenolic content in F extract was 52.271 mg gallic acid equivalent (GAE) per gram of dry extract significantly higher than 32.170 recorded in H extract. Similarly, F extract exhibited significantly higher flavonoid content of 594.537(QE)) than 357.471 (QE) recorded for H extract. None of the formulations gave 100% complete wound healing on the 18th day of treatment. However, the monotherapy formulations performed better than the polyherbal formulations. The 10% dosage formulation of H recorded the highest percentage wound healing (97.4) whereas the 20% dosage of 1:2 F and H formulation recorded the highest percentage wound healing activity (93.8%) among the polyherbal treatments.