Abstract:

The ripe fruit of wild hill gooseberry (Rhodomyrtus tomentosa) was analyzed for its antioxidant activity, total
phenolics, total flavonoids, ascorbic acid contents, and anthocyanin composition. Ultra performance liquid chromatography
coupled to photo-diode array and ion-trap mass spectrometry (UPLC-PDA-IT-MS) was used to identify the anthocyanin
composition. The antioxidant activity was determined by high-throughput free radical scavenging assay. As a result, the wild
hill gooseberry had a higher antioxidant capacity. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was
expressed as 67.2 μmol of ascorbic acid and 28.5 μmol of gallic acid equivalents per g of hill gooseberry. The peroxyl radical
scavenging capacity (PSC) was expressed as 23.2 μmol of ascorbic acid and 14.3 μmol of gallic acid equivalents per g of hill
gooseberry. The 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity was expressed as
30.4 μmol of ascorbic acid and 7.8 μmol of gallic acid equivalents per g of hill gooseberry. The ferric reducing antioxidant power
(FRAP) was expressed as 28.7 μmol of ascorbic acid and 3.1 μmol of gallic acid equivalents per g of hill gooseberry. Total
phenolics and total flavonoids contents (on a dry weight basis) were 4 976 mg GAE/100 g md and 49.7 mg catechin/100 g md,
respectively, and total ascorbic acid content (on a fresh weight basis) was 9 mg/100 g mf. Total monomeric anthocyanin content (on
a dry weight basis) was 414 mg/100 g md. Seven anthocyanins including delphinidin 3-O-glucoside were identified. Cyanidin
3-O-glucoside was the most predominated form, followed by peonidin 3-O-glucoside and delphinidin 3-O-glucoside.

Key words: hill gooseberry, anthocyanins, antioxidant components, antioxidant properties