Effects of extraction temperature on bioactive compounds and antioxidant activity of yellow velvetleaf (Limnocharis flava) and water lettuce (Pistia stratiotes) leaf extract

Abstract

Oxidative stress is considered a source of metabolic disorders. It is caused by an imbalance between the body's antioxidant potential and free radical production. Therefore, the body needs exogenous antioxidants, such as the bioactive compounds of plants. The yellow velvetleaf (Limnocharis flava) and water lettuce (Pistia stratiotes) leaf showed potential antioxidant activity because of their polyphenol compounds. This study aimed to investigate the effects of extraction temperature on polyphenols and flavonoids as well as their antioxidant activity on yellow velvetleaf and water lettuce leaf. The plant was extracted by the maceration method in various processes using 70% ethanol. The results showed the total polyphenol (TPC) and flavonoid content (TFC), as well as the antioxidant content determined using the DPPH method. The highest TPC (512.5 mg GAE/g of dried sample; 273.7 mg GAE/g of the dried sample) and TFC (209.5 mg QE/g of dried sample; 641 mg QE/g of the dried sample) were observed in low-temperature extraction. Under these conditions, the highest antioxidant activity (IC50) of yellow velvetleaf and water lettuce was 0.207 mg/mL and 0.227 mg/mL, respectively. A low extraction temperature is optimal for extracting these bioactive compounds, primarily from yellow velvetleaf and water lettuce leaf.