Relative Free Radicals Scavenging and Enzymatic Activities of Hippophae rhamnoides and Cassia fistula Extracts: Importance for Cosmetic, Food and Medicinal Applications

Hippophae rhamnoides L. and Cassia fistula L. extracts have great potential as food, medicinal, or cosmetic ingredients. The aim of our study was to assess their relative antioxidant activities and key enzymatic activities. Thereby, H. rhamnoides’ fruit and C. fistula’s pod extracts were evaluated by spectrophotometry, based on their respective total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) ferric-reducing power, capacity in nitric oxide, hydroxyl and superoxide radicals scavenging, as well as on their β-glucuronidase, α-glucosidase and α-tyrosinase inhibition activities. H. rhamnoides and C. fistula extracts exhibited similarly high TPC levels, hydroxyl ion [OH•] quenching activity, and α-glucosidase and α-tyrosinase IC50 values (p > 0.05). However, their respective DPPH radical, nitric oxide radical [NO•], and superoxide anion [O2] scavenging activities, as well as their IC50 values for β-glucuronidase, significantly differed (p ≤ 0.05), with results showcasing the highest values in C. fistula extracts. In sum, our in vitro data explicitly suggest that the pod extracts of C. fistula exert better antioxidant and enzymatic properties than those exhibited by the fruit extract of H. rhamnoides. They also implicitly encourage performing multiple in vitro assays in order to thoroughly select a plant extract destined to a given medicinal, dietetic, or esthetic application.