2 2 azinobis 3 ethylbenzothiazoline 6 sulfonic acid (abts)

The antioxidant activities of the 30%, 60%, and 95% ethanol extracts of R. himalense fruits were determined microassay, using the T‐AOC assay (DPPH, ABTS, and FRAP) kits purchased from Suzhou Comin Biotechnology Co., Ltd. (Jiangsu, China). The scavenging capability for DPPH free radical and ABTS radical cation (ABTSˑ⁺) was evaluated by applying a microplate reader in absorbance at 515 and 734 nm, respectively (Abreu et al., 2019; Arts et al., 2004; Souza et al., 2020). The results of DPPH and ABTS were expressed as trolox equivalent antioxidant capacity (TEAC), which is µmol TEAC/g fresh weight and determined via a calibration curve, such as y = 0.7072x − 0.0081, R² = 0.9977 and y = 0.7021x − 0.0012, R² = 0.9985. The antioxidant activity was conducted using ferric reducing antioxidant power (FRAP) assay method, that is, under acidic conditions, the ability of antioxidants to reduce Fe³⁺‐TPTZ (2,4,6‐tripyridyl‐s‐triazine) to produce blue Fe²⁺‐TPTZ (Asghar et al., 2019; Oikeh et al., 2016; Razak et al., 2015). The absorbance was measured at 593 nm, and the FRAP results were represented as Fe (II) equivalent antioxidant capacity, which is µmol Fe (II)/g fresh weight, and determined via a standard curve (y = 1.2416x + 0.0134, R² = 0.9996). The analyses were carried out in triplicate for each concentration.