Evaluation of Wound Closure Activity of Nigella sativa, Melastoma malabathricum, Pluchea indica, and Piper sarmentosum Extracts on Scratched Monolayer of Human Gingival Fibroblasts

Nigella sativa, Melastoma malabathricum, Pluchea indica, and Piper sarmentosum are common Asian traditional medicines to treat minor wounds. This study aimed to investigate the in vitro wound healing properties of aqueous extracts of these plants using human gingival fibroblast (HGF) monolayer as study model. DPPH scavenging activity of the extracts was evaluated and effect on HGF proliferation was determined. Their effect on HGF's function to synthesize collagen was indicated by the level of hydroxyproline produced and effect on wound healing activity was assessed using an in vitro scratch assay. The influence of the extracts on expression of bFGF and TGF-β was also determined. Results revealed all four extracts to exhibit low free radical scavenging activity. The extract from N. sativa (NSSE) compared to the others showed favourable enhancement of HGF proliferation with EC50 of 22.67 ± 3.06 µg/mL (P < 0.05) with accelerated wound closure activity despite its nonsignificant effect on collagen synthesis. In addition to the elevated level of bFGF by up to 15% at 100 µg/mL of NSSE, a slightly better effect was observed on the expression of TGF-β. NSSE thus showed that promising wound healing properties and data obtained may contribute towards validation of its traditional use for the healing of oral wounds.