Enzymatic defence mechanisms in Sapindus mukorossi and Acacia concinna: A Michaelis Menten model approach

Sapindus mukorossi (soapnut) and Acacia concinna, belonging to the families Sapindaceae and Leguminosae respectively, are medicinal plants known for their high saponin content as part of their adaptation and defence strategies against environmental stresses. This study investigates and compares the enzymatic antioxidant defence responses of these two saponin rich species, focusing on key enzymes involved in plant stress role in plant adaptation. Enzymatic assays displayed notable differences in the activities of catalase, peroxidase, and polyphenol oxidase; Acacia concinna possessed higher overall enzymatic activity, while Sapindus mukorossi possessed higher polyphenol oxidase activity reflecting their ecological adaptation and biochemical resilience. The comparative kinetic profiling highlights the enzymatic adaptability of both species under oxidative stress, emphasizing the ecological and biochemical roles of saponins in defence. Linear Discriminant Analysis (LDA), which captured 96.53 percent of the total variation, proved a clear isolation based on enzymatic profiles. Post hoc analysis confirmed statistically significant differences (p ≤ 0.05) in enzyme activity between the two species. These findings provide insights into the metabolic resilience of saponin-rich plants and contribute to understanding plant defence mechanisms in stressful environments.