Phytochemical analysis, antioxidants, α-glucosidase inhibitory activity, and Toxicity Evaluation of Orthosiphon stamineus leaf extract

Abstract The potency of O. stamineus as a herbal candidate has been evaluated by previous studies. The goal of this study is to compare water and a 100% ethanolic extract of O. stamineus to see which one is more effective as an α-glucosidase inhibitor and antioxidant. However, these parameters are critical in the development of herbal medicines. Furthermore, the toxicity of this herb is assessed. According to this study, water extract of O. stamineus leaves has a better inhibition activity of α-glucosidase, ABTS, and DPPH, with IC50 values of approximately 43.623±0.039 µg/mL, 27.556±0.125 µg/mL, and 95.047±1.587 µg/mL, respectively. The major active compounds are fatty acid groups such as Ethyl myristate (Tr: 20.8 min); 6-(Stearoyloxy)octadecanoic acid (Tr: 20.75 min); Linoleic acid (Tr: 23.09 min); Oleic acid (Tr: 23.22 min); and phenolic groups including D-(-)-Quinic acid (Tr:1.3 min) and Caffeic acid (Tr: 5.2 min); and carboxylic acid groups and its derivate including 2-(Benzoyloxy)-3-hydroxysuccinic acid (Tr: 7.85 min) and Tuberonic acid (Tr: 9.67 min). Therefore, this study also found that the water extract of this herb is non-toxic to zebrafish embryos and has no effect on zebrafish larvae development at concentrations less than 500 g/mL.