LCHRMS-based metabolomics on Acalypha indica with different altitude and antioxidant activity

Achalypha indica is a weed that has medicinal properties. This study aims to determine the metabolite profile and evaluate the antioxidant activity of A. indica from areas with different altitudes, Tuban (20 to 50 masl; TBN), Banyuwangi (60 to 90 masl; BB), Magetan (300 to 600 masl; MGT), and Malang (500 to 800 masl; MLG). The ethanol extract of A. indica was analyzed for total phenolics and antioxidant activity. Separation and identification of samples were carried out using liquid chromatography-high-resolution mass spectrometry (LC HRMS), then classified by Principal Component Analysis (PCA). The total phenol value ranged from 6.83 to 10.67 mg GAE /g of dry powder, with an antioxidant IC 50 of 86.09 to 118.96 µg/mL. LC HRMS successfully identified 83 metabolites. PCA analysis was able to clearly distinguish each sample based on the altitude of the growing location with a total variance value reaching 82 % (PC-1: 57 %, and PC-2: 25 %). Heat map analysis that observes variations in metabolite composition in each sample shows an increase in the content of flavonoid compounds in the lowlands under certain geographical conditions. Therefore, the height of the growing location has a significant influence on the metabolite profile and antioxidant activity. These findings are very important for assessing the quality, safety, and efficacy of medicinal plant raw materials.