Phytochemical, Metabolite Compound, and Antioxidant Activity of Clinacanthus nutans Leaf Extract from Indonesia

Abstract

The antioxidant properties from medicinal plants have protective effects against oxidative stress-linked diseases. Their antioxidantcapacities are related to phenolic compounds, including phenols and flavonoids.Clinacanthus nutans, a native to Asia, includingMalaysia, Thailand, and Indonesia, are used for treating diabetes and other diseases, but the exploration of the plant in Indonesia isstill limited. Therefore, this study aimed to reveal the phytochemical constituents, metabolic compounds, and antioxidant activityofC. nutansextracts. Dried leaf powder was extracted with 70% ethanol and aqueous, each extract was subjected to qualitativephytochemical screening. Subsequently, total phenolic and flavonoid content was calculated using Folin-Ciocalteu and AlCl3colorimetric assay. The antioxidant activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavengingmethod. Theprofilesofphenolicandflavonoidcompoundsof70%ethanolicextractwereinvestigatedbyLC-MS/MS.Phytochemicalscreening showed that the extracts contain phenolic, flavonoid, tannin, and saponin. The total phenolic content of the 70% ethanolandaqueousextractwas4.14±1.9%mgGAE/gand3.89±3.2%mgGAE/g, respectively. Meanwhile, thetotalflavonoidcontentobtainedwas 0.19±1.0% mgQE/g and 0.03±0.5% mgQE/g for 70% ethanol and aqueous extracts, respectively. Both extracts showed highantioxidant activity, with DPPH IC50 30.57 𝜇g/mL for 70% ethanol and 37.24 𝜇g/mL for aqueous extract. LC-MS/MS analysis of70% ethanol extract revealed 5 phenolic and 3 flavonoid compounds, where DL-glutamic monohydrate and Boesenbergin B werethe most dominant based on the percentage of area under the curve.C. nutansoriginating from Indonesia can be a good source ofnatural antioxidants because 70% ethanol and aqueous extract show high phytochemical content and antioxidant activity.