Objective To evaluate three flowers of Hibiscus rosa-sinensis (H. rosa-sinensis), Quisqualis indica (Q. indica) and Senna surattensis (S. surattensis) for their antioxidant activity by different methods in addition to total phenolic, flavonoid and pigment contents. Methods Antioxidant activity of water, ethanol and absolute ethanol extracts of three flowers; H. rosa-sinensis, Q. indica and S. surattensis was evaluated. The antioxidant activity was assessed by 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity, ferrous chelating activity, reducing power, nitric oxide scavenging activity, hydroxyl radical scavenging activity as well as total antioxidant capacity. Total flavonoids, total phenols and total pigments including chlorophylls and carotenoids were measured for the three flowers. Results The results showed that the highest total antioxidant capacity at concentration of 500 mg/L was found in S. surattensis as 0.479 ± 0.001. Scavenging activity of H. rosa-sinensis, Q. indica and S. surattensis flower extracts against 1,1-diphenyl-2-picrylhydrazyl radical showed the highest activity of (90.20 ± 0.29)% with 500 mg/L. Phytochemical screening of the three flowers extracts were carried out for alkaloids, flavonoids, saponins, tannins, steroids, glycosides, terpenoids, amino acid and mucilages. H. rosa-sinensis showed the total phenolic in water extract of (235.77 ± 14.31) mg/100 g, the other two flowers Q. indica and S. surattensis had the total phenolic in ethanol extracts of (937.70 ± 25.06) and (850.30 ± 13.81) mg/100 g, respectively. On the other hand total flavonoids were identified in absolute ethanol extracts in the three flowers [(32.83 ± 1.34), (49.24 ± 4.87) and (2.79 ± 0.23) mg/100 g, respectively]. Conclusions The extracts in the constituents of the three flowers could be used as additives as supplement fractions in foods.

Objective: To evaluate the antioxidant and antidiabetic mechanism(s) of ethyl acetate extract fraction of Moringa oleifera (M. oleifera) leaves on streptozotocin-induced diabetes in male Sprague-Dawley rats. Methods: A total of 24 adult male rats were segregated randomly into four groups (6 rats each group). Streptozotocin-induced diabetes rats were given (oral gavage) ethyl acetate extract fraction of M. oleifera (200 mg/kg b.w.) for 30 d. The rats of control and experimental groups were sacrificed after 24 hours of final dose of treatment, to extract blood and pancreatic tissue for biochemical and histopathological analysis. Results: The ethyl acetate extract fraction of M. oleifera significantly reversed (P<0.05) the manifestation of streptozotocin on the levels of serum glucose & insulin, lipid profile, hepatic damage markers (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase), malondialdehyde formation, antioxidants (glutathione, Vitamin C & Vitamin E), antioxidant enzymes (superoxide dismutase, glutathione S-transferase, glutathione peroxidase and catalase) and pro-inflammatory cytokines (IL-1 β , TNF- α & IL-6). Histopathological analysis of pancreatic tissues was in concurrence with the biochemical results. Conclusions: These findings support that M. oleifera leaves have potent therapeutic effect on diabetes mellitus via increasing antioxidant levels and inhibition of pro-inflammatory mediators.