Optimization of Microwave-Assisted Extraction Conditions for Total Saponin Content and Antioxidant Activity of Launaea sarmentosa Leaves

Abstract

Launaea sarmentosa is an herbaceous plant rich in saponin, especially in the leaves. The plant has been shown to have antioxidant activity. The present study aimed to optimize the extraction conditions for maximizing both total saponin content (TSC) and antioxidant activity of the plant leaves. To achieve this, Response Surface Methodology (RSM) was applied using a Box-Behnken Design (BBD), which involved three independent variables: microwave power, extraction time, and ethanol concentration. These parameters were systematically optimized to maximize the extraction yield of the desired bioactive compounds. TSC was determined spectrophotometrically using diosgenin as the reference standard. Antioxidant activity was assessed through the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging method. The optimal conditions determined through the model were microwave power of 330 W, extraction time of 22 minutes, and ethanol concentration of 64%. Under these conditions, the experimental values of TSC and antioxidant activity were found to be 9.56 ± 0.24 mg DE/g dry weight and 87.62 ± 0.46%, respectively. The findings indicate that microwave-assisted extraction, when optimized using RSM, is an effective approach for enhancing the recovery of bioactive components from L. sarmentosa. This study provides a scientific basis for the efficient use of this plant as a natural source of antioxidants. In addition, the results gave valuable insights into the development of plant-based functional ingredients for pharmaceutical and nutraceutical applications. By optimizing the extraction conditions, this work demonstrated the potential of Launaea sarmentosa as a promising candidate for use in health-promoting products, paving the way for its broader industrial application.