Antidiabetic and antihypertensive effect of a polyphenol‐rich fraction of Thymelaea hirsuta L. in a model of neonatal streptozotocin‐diabetic and N^G‐nitro‐l‐arginine methyl ester‐hypertensive rats

Abstract

Background: The present study examined the effect of the polyphenol-rich fraction from Thymelaea hirsuta (PRF-Th) in a rat model of streptozotocin (STZ)-diabetes and nitric oxide (NO)-deficient hypertension. Methods: Diabetes was induced by a single dose of STZ (90 mg ⁄ kg, i.p.). To induce NO-deficient hypertension, rats were treated with the NO synthase inhibitor N G -nitro-l-arginine methyl ester; l-NAME; 30 mg ⁄ kg per day, p.o. for 3 weeks. The effects of 21 days treatment with 80 mg ⁄ kg per day PRF-Th in the drinking water were evaluated in diabetic-hypertensive (DH) rats. In all groups (n = 6 in each), glycemia and systolic blood pressure were determined weekly. At the end of the experiment, hepatic glycogen was determined. Results: Blood glucose levels decreased gradually from baseline until the end of the experiment in untreated DH rats (from 1.92 ± 0.09 to 1.3 ± 0.1 g ⁄ L; P < 0.05). Administration of PRF-Th concomitantly with l-NAME prevented the blood pressure increase in rats. After 21 days, blood pressure in PRF-Th + l-NAME-and l-NAME-treated rats was 132 ± 1 and 157 ± 1 mmHg, respectively (P < 0.001). Administration of 2 mL ⁄ kg per day PRF-Th to DH rats significantly increased hepatic glycogen levels compared with levels in untreated DH rats (13.65 ± 1.84 vs 6.34 ± 0.75 mg ⁄ g tissue, respectively; P < 0.01). Moreover, PRF-Th significantly reduced the amount of glucose absorbed in in situ perfused jejunum segments compared with control (by 33.6%; P < 0.001). This effect of PRF-Th was comparable with that of acarbose, an a-glucosidase inhibitor. Conclusions: The findings of the present study indicate that T. hirsuta has antidiabetic and antihypertensive activity in STZ-diabetic, NO-deficient hypertensive rats. This effect seems to be due to its rich polyphenol content. Therefore, T. hirsuta may be useful as a food supplement for the prevention of type 2 diabetes and hypertension.

Inhibition of α‐glucosidase and glucose intestinal absorption by Thymelaea hirsuta fractions (毛花瑞香成分对α‐糖甙酶以及肠道葡萄糖吸收的抑制作用)

“…Thymelaea hirsuta contains sterols (cholesterol, campesterol, β‐sitosterol, β‐sitosterol‐ β‐stigmasterol), coumarins (daphnoretin, daphnin, daphnetin, daphnetin‐glucoside, umbelliferone, scopoletin and esculetin), terpenes (lupeol, phytol, β‐amyrine, betulin, erythrodiol, and lanosterol), a flavone (2‐vicenin), the flavonol tiliroside (3‐p‐coumaroylglucosylkaempferol), tannins, an aliphatic alcohol (C12H22O), a lactone (C19H18O6); long chain alkanes (27‐31 carbons), long chain alcohols (22, 24, 26, 28 carbons) and 5,12‐dihydroxy‐6,7‐epoxy‐resiniferonol …”

“…aliphatic alcohol (C12H22O), a lactone (C19H18O6); long chain alkanes (27-31 carbons), long chain alcohols (22,24,26,28 carbons) and 5,12-dihydroxy-6,7-epoxyresiniferonol. 7,22 Previous studies have shown that T. hirsuta is rich in polyphenols 9 and essential oil. 11 Therefore, the polyphenols and essential oil compounds are most likely responsible for the antioxidant activity.…”

“…(Thymelaeaceae), widely distributed in the Mediterranean area, are used to prevent and treat diabetes . Previous studies in our laboratory have demonstrated the antihyperglycemic activity of a polyphenol‐rich fraction of this plant (PrF‐TH) . Moreover, this plant has demonstrated hypoglycemic, antidiabetic, antioxidant, antimelanogenesis, and antiseptic activities…”

“…4,5 Previous studies in our laboratory have demonstrated the antihyperglycemic activity of a polyphenol-rich fraction of this plant (PrF-TH). 6,7 Moreover, this plant has demonstrated hypoglycemic, antidiabetic, 8 antioxidant, 9 antimelanogenesis, 10 and antiseptic activities. 11 No information in the literature was found on its mechanism of action concerning its antihyperglycemic activity.…”

Phytochemical Investigations and Antibacterial and Antioxidant Properties of Thymelaea Microphylla Essential Oil

“…antidirehyde and purgative and in the treatment of influenza 1-2,5-6,10, [13][14][15][16][17] . In M'Sila region, T. hirsuta is recommended by herbalists for the treatment of human diseases (Leishmanicide, dewormer and eczema) 18 .…”