Identification of Antioxidant Compounds from Gynura procumbens Using LC-MS/MS-Based Metabolomics

Gynura procumbens or commonly known as sambung nyawa is one of Indonesian medicinal plants. This plant has antioxidant activity, but no reported studies have been performed to identify antioxidant compounds from G. procumbens leaves using a metabolomics approach. In this study, we aimed to identify antioxidant compounds from G. procumbens by LC-MS/MS-based metabolomics. G. procumbens was extracted by maceration using ethanol p.a, 70%-, 50%-, 30% ethanol, and water as the extracting solvent. Metabolite profiling using LC-MS/MS could putatively identify about 54 metabolites from all extracts. We found that flavonols are the most abundant group in all ethanol extracts. Antioxidant activity was determined using the DPPH method. The antioxidant activity of all extracts yielded IC50 values ranging 90.39 to 140.75 mg/L, indicating strong to medium activity. Antioxidant compound prediction was done by correlating metabolites profile and antioxidant activity using orthogonal partial least square-discriminant analysis (OPLS-DA). From the OPLS-DA, five compounds are predicted as antioxidant compounds, namely kaempferol 3-O-rutinoside, 4-hydroxybenzaldehyde, 4,5-dicaffeoylquinic acid, 3-dicaffeoylquinic acid, and 1 unknown compound. The five metabolites had a p-value (<0.05), fold change (>1.5), and variable importance in the projection (VIP) (>1.46), which indicated that these metabolites had a significant contribution to the antioxidant activity from G. procumbens leaves.