Effect of Honghua (Flos Carthami) on nitric oxide production in RAW 264.7 cells and α-glucosidase activity
Lao, H, Banbury, L, Liang, H, Wang, X, Lü, X, Hu, L & Wu, J 2014, 'Effect of Honghua (Flos Carthami) on nitric oxide production in RAW 264.7 cells and α-glucosidase activity', Journal of Traditional Chinese Medicine, vol. 34, no. 3, pp. 362-368.
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Objective: To study the effects of extracts from Honghua (Flos Carthami) on lipopolysaccharide induced nitric oxide (NO) production in RAW 264.7 cells and the influence of the extracts on yeast α-glucosidase activity. The total flavonoid content of the extracts was also determined. Methods: Cytotoxicity of the extracts to RAW 264.7 cells was evaluated by the ATPlite™ method. Inhibitory effects of the extracts on NO production were evaluated by Griess assay. Curcumin was used as a positive control. Screening of extracts for potential α-glucosidase inhibitors was done by a fluorometric assay. The assay was based on the hydrolysis of 4-methylumbelliferyl-a-D-glucopyranoside to form the fluorescent product, 4-methylumbellifer-one. Acarbose was used as a positive control. The total flavonoid content was tested using kaempferol as the standard. Results: There were significant inhibitory effects on NO production when the extracts were 25-100 μg/mL (P<0.05) and curcumin was 2-4 μg/mL (P< 0.001). The extracts showed an inhibitory effect on α-glucosidase activity at the concentrations of 15.6-125 μg/mL with a half maximal (50%) inhibitory concentration (IC50) of (32.8 ± 5.7) μg/mL, compared with the IC50 of acarbose at (1.8±0.4) μg/mL. There was a significant difference between the two IC50 values (P<0.001). The total content of flavonoids per gram of dried herb was 1.14 mg. Conclusion: Honghua (Flos Carthami) showed inhibitory effects on NO production in activated RAW 264.7 macrophage cells and an inhibitory effect on yeast α-glucosidase. There might be a relationship between these pharmacological effects and its flavonoid content.