Study of the Antioxidant and Antidiabetic Properties of the Alga Halopteris Scoparia: In Vitro and In Vivo Evaluation in Alloxan-Induced Diabetic Mice

Halopteris scoparia is an edible brown algae seaweed with significant biological activities. This study aimed to explore the biological and toxicological activities of the methanol extract of Halopteris scoparia. The study included a comprehensive evaluation of the phytochemical composition of the extract, as well as its antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging, and Ferric reducing antioxidant power (FRAP) assays. Antidiabetic activity was evaluated in vitro using α-amylase and α-glucosidase inhibitory assays, and in vivo in alloxan-induced diabetic mice. Toxicological effect was investigated in vivo by acute toxicity and sub-acute toxicity tests in mice. Phytochemical analysis revealed a rich phytochemical profile of Halopteris scoparia, with phenolic and flavonoid contents of 55.47 ± 0.70 mg GAE /g and 147.67 ± 1.53 mg QE/g, respectively. LC-MS analysis revealed various bioactive compounds. Halopteris scoparia extract showed remarkable antioxidant potential, with IC50 values of 1.213 ± 0.290 mg/mL and 2.671 ± 0.210 mg/mL in the DPPH and ABTS radical scavenging assays, respectively, and FRAP value of 82.215 ± 0.970 mg AAE/g. Halopteris scoparia extract exhibited promising antidiabetic activity by demonstrating significant α-amylase and α-glucosidase inhibitory activities in vitro, and potent hypoglycaemic effect in vivo comparable to that of glibenclamide. In addition, Halopteris scoparia extract significantly decreased malondialdehyde, and increased the levels of antioxidant enzymes in the pancreas, liver and kidneys of diabetic mice. These results highlight the potentials of H. scoparia extract as a relatively safe natural antioxidant and alternative source of antidiabetic agent(s).