Synergistic-antagonistic interaction of vegetable extracts, Acalypha indica, Centella asiatica, and Sesbania grandiflora: Wound healing, antioxidant, protectivity, and antimicrobial properties

ABSTRACT

Aims@#Acalypha indica (AI), Centella asiatica (CA), and Sesbania grandiflora (SG) are vegetables commonly used in traditional medicine in Asian countries to treat skin problems. In this study, we investigated their pharmacological activities relevant to wound healing and synergistic actions to provide an insight into a promising vegetable combination as a candidate treatment for wounds. @*Methodology and results@#The stimulatory, antioxidant, and antibacterial activities of aqueous (A) and methanol (M) extracts of all the three vegetables were assessed alone and in combination in normal human dermal fibroblast (NHDF) cells in vitro. CA-A (89.52%) and the combination of AI-A+CA-A (90.76%) produced the highest percentage of wound closure. AI-A exhibited the highest total phenolic content (TPC) (82.94 mg GAE/g) and moderate reducing activity (61.63 mM Fe (II)/mg) when assessed by ferric reducing antioxidant power (FRAP) assay. Free radical scavenging activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), and the combination of AI-A+CA-A exhibited scavenging activity at IC50 = 379.75 µg/mL and IC50 = 578.7 µg/mL, respectively. Pre-treatment of NHDF cells with CA-M at 100 µg/mL offered the highest protection against hydrogen peroxide. All single and combined vegetable extracts showed poor antibacterial properties against Gram negative and Gram positive bacterial species implicated in wound infection. Only AI-A+CA-A executed synergism in fibroblast migration when assessed via the combination index (CI). Furthermore, screening and identification of AI-A, CA-A, and CA-M via UHPLC (LC-MS/MS) system revealed that the major components responsible for all the tested bioactivities were phenolic groups such as simple polyphenols, flavonoids, polysaccharides, and triterpenes (asiaticoside and madecassosides). @*Conclusion, significance and impact of study@#The vegetable extracts of A. indica, C. asiatica, and S. grandiflora exhibited good bioactivities independently. However, only AI-A+CA-A showed synergism in combination to accelerate the migration of fibroblast and increase antioxidant activities. These findings demonstrate the potential formulation of combined vegetable extracts from the two species of A. indica and C. asiatica for optimum wound healing properties.