HPLC-DAD-MS/MS profiling of phenolics from Securigera securidaca flowers and its anti-hyperglycemic and anti-hyperlipidemic activities
Securigera securidaca (L.) Degen & Doefl., Fabaceae, has been widely used in the Iranian, Indian and Egyptian folk medicine as antidiabetic and anti-hyperlipidemic remedy. Phenolic profiling of the ethanolic extract (90%) of the flowers of S. securidaca was performed via HPLC-DAD-MS/MS analysis in the positive and negative ion modes. The total polyphenols and flavonoids in the flowers were determined colorimetrically, and the quantification of their components was carried out using HPLC-UV. Total phenolics and flavonoids estimated as gallic acid and rutin equivalents were 82.39 ± 2.79 mg/g and 48.82 ± 1.95 mg/g of the dried powdered flowers, respectively. HPLC-DAD-MS/MS analysis of the extract allowed the identification of 39 flavonoids and eight phenolic acids. Quantitative analysis of some flavonoids and phenolics (mg/100 g powdered flowers) revealed the presence of isoquercetrin (3340 ± 2.1), hesperidin (32.09 ± 2.28), naringin (197.3 ± 30.16), luteolin (10.247 ± 0.594), chlorogenic acid (84.22 ± 2.08), catechin (3.94 ± 0.57) and protocatechuic acid (34.4 ± 0.15), in the extract. Moreover, the acute toxicity, hypoglycemic and hypolipidemic effects of the extract were investigated using alloxan induced diabetes in rats in a dose of 100, 200, and 400 mg/kg bwt. The ethanolic extract was safe up to a dose of 2000 mg/kg. All tested doses of the flower extract showed marked decrease in blood glucose level by 31.78%, 66.41% and 63.8% at 100, 200 and 400 mg/kg bwt, respectively, at p < 0.05. Regarding the anti-hyperlipidemic effect, a dose of 400 mg/kg of the flower extract showed the highest reduction in serum triacylglycerides and total cholesterol levels (68.46% and 51.50%, respectively at p < 0.05). The current study proved the folk use of the flowers of S. securidaca as anti-diabetic and anti-hyperlipidemic agent which could be attributed to its high phenolic content.