Objectives: The antioxidant activities of two Indian mangrove plants, Bruguiera cylindrica and Ceriops decandra, were investigated.
Materials and methods: Total phenolics and total flavonoid contents of the mangroves were determined using folin-ciocalteu reagent method and aluminium chloride method, respectively. Antioxidant capacity was assessed by the following methods: 1,1-diphenyl-2-picryl hydroxyl (DPPH.) quenching assay; 2,2'- azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS.(+)) cation decolorization test; scavenging capacity towards hydroxyl ion radicals (.OH); reductive capacity; and antihemolytic activity.
Results: The mangroves yielded 233.3 ± 0.062 and 283.31 ± 0.04 mg gallic acid equivalent/g phenolic contents and 11.6 ± 0.12 and 15.1 ± 0.02 mg quercetin equivalent/g flavonoid contents. The methanol extracts of both mangroves exhibited high antiradical activity against DPPH., ABTS.(+), and .OH radicals. The reductive capacity of the extracts increased with increasing concentration of samples. The extracts also inhibited H(2)O(2) induced hemolysis in cow blood erythrocytes. The antioxidant activities were found stronger than that of the reference standard, butylated hydroxy toluene (BHT). The antioxidant activity of mangrove plants was correlated with total phenolics and flavonoid contents.
Conclusion: Both plants can be considered as good sources of natural antioxidants for medicinal uses. Further studies are necessary to isolate active principles responsible for the overall antioxidant activity of the extracts.
Keywords: ABTS.+ assay; Bruguiera cylindrica; Ceriops decandra; DPPH.; H22 induced mangroves; red blood cell hemolysis; total flavonoids; total phenolics.