Comparative analysis of in vitro antioxidant and wound healing activities of Indian paalai plant extracts and investigation of their phytochemical profile by GC-MS

Abstract

Wound healing refers to the natural physiological process comprising four overlapping phases through which the body restores damaged tissues following an injury. One of the factors that affect wound healing is oxidative stress caused by excessive release of reactive oxygen species (ROS). Conventional wound care often includes the use of antibiotics and antiseptics. However, they do not act specifically against oxidative stress and also pose a significant risk for allergies and irritations, highlighting the necessity for alternative treatment approaches. Phytomedicines, such as vetpaalai thailam derived from Wrightia tinctoria leaves, offer promising alternatives for wound healing in Indian system of medicine. While vetpaalai has been traditionally used for this purpose, other plants with similar nomenclature in local Tamil language, including Alstonia scholaris (Ezhilaipaalai), Argyreia nervosa (Kadarpaalai), Aristolochia bracteolata (Aadutheendapaalai), Holarrhena pubescens (Kudasapaalai) and Manilkara hexandra (Ulakaipaalai), remain unexplored in this regard. Therefore, in this project the antioxidant and wound healing activities of various paalai plants were assessed through in vitro assays. The ROS scavenging activity, cytotoxicity and cell proliferation properties of paalai plant extracts were compared to understand their wound healing potential. Extracts of paalai plants demonstrated better antioxidant activity compared to their respective oils in each sample. Among extracts, M. hexandra recorded superior antioxidant activity, demonstrated cytotoxic effects on cells and did not promote scratch closure, suggesting limitations in its potential for wound healing applications. Alternatively, A. nervosa and A. scholaris extracts exhibited better antioxidant activity, enhanced scratch (wound) closure, and demonstrated safety, indicating their potential wound healing efficacy. Among the investigated paalai plants, extracts of A. nervosa and A. scholaris were found to possess promising activity to reduce the oxidative stress and promote cell migration and proliferation based on in vitro wound healing studies. Additional research is necessary to investigate their precise mechanisms and development of potential commercial products for wound healing.