Long-Term Effect of an AqueousFraxinus excelsiorL. Seed Extract in Spontaneously Hypertensive Rats

Abstract

The effect of long-term intake of different doses (20, 40, and 60 mg/kg/day) of a Fraxinus excelsior L. seed extract (FESE) on spontaneously hypertensive rats (SHR) was evaluated. Water was used as control and captopril (50 mg/kg/day) was used as positive control. Systolic blood pressure, body weight, and food and liquid intake were registered weekly in SHR. The antioxidant and vascular relaxing properties of FESE were also studied in these animals. The development of hypertension was attenuated in the groups treated with captopril or FESE. The antihypertensive effect was more accentuated in the captopril group than in the FESE groups, and it was paradoxically more accentuated in the groups treated with 20 mg/kg/day or 40 mg/kg/day of FESE than in the group treated with the highest dose of this extract. Body weight gain and food intake increased in the FESE groups. After removing the corresponding antihypertensive treatment, the arterial blood pressure and the body weight of the FESE treated animals returned to control values. In addition, FESE increased plasma antioxidant capacity and decreased plasma and liver malondialdehyde levels. Moreover, acetylcholine relaxation improved in the aorta rings from the FESE treated rats.

Lack of Tissue Accumulation of Grape Seed Flavanols after Daily Long-Term Administration in Healthy and Cafeteria-Diet Obese Rats

“…Hence, the health effects of flavanols as evidenced in long-term studies with a disease state could interestingly be attributed to a kind of pulsatile and repetitive effect of the bioactive forms of flavanols. This timely strategy would be in agreement with previous studies that reported that polyphenols exhibited health effects at short times after their acute ingestion, being reversed at longer times. ,,, Moreover, rapid reversions of the health benefits of polyphenol-rich products (increasing blood pressure) were observed after halting their long-term administration to hypertensive rats. ,, …”

Targeted and Untargeted Metabolomics to Explore the Bioavailability of the Secoiridoids from a Seed/Fruit Extract (Fraxinus angustifolia Vahl) in Human Healthy Volunteers: A Preliminary Study

“…Blood (5 mL) was collected into heparinized tubes from the antecubital arm vein: one sample at baseline (8.00 a.m. before Fraxinus intake, control) and several samples at predetermined time points (1, 2, 4, and 8 h) following a single acute dose of the Fraxinus extract in hard capsules (3 × 334 mg) with a glass of water. This dose was chosen according to that used in previous animal and human studies [2,3,4,5,6,7] reporting some metabolic beneficial effects. The volunteers were asked to come back the following morning (8.00 a.m. before breakfast) for a further 24 h blood sample extraction.…”

“…The genus Fraxinus (Oleaceae) which contains a wide range of phytochemicals, mostly secoiridoid glucosides, coumarins and phenylethanoids, but also some flavonoids, benzoquinones, indole derivatives and simple phenolics has been commonly used in traditional medicine against various inflammatory diseases, infections, constipation, as a diuretic and as a hepatoprotective agent [1]. Additionally, an extract produced from the seeds/fruits of Fraxinus has been shown to moderate body weight gain, body fat, glucose and insulin levels, fatty liver incidence as well as blood pressure in various animal models of obesity, diabetes and hypertension [2,3,4,5] supporting potential beneficial properties of Fraxinus against metabolic disorders. These beneficial effects were observed with doses ranging between 100 and 200 mg per kg of body weight per day, corresponding to a Human Equivalent Dose (HED = animal dose in mg/kg × (animal weight in kg/human weight in kg) 0.33 ) of ~1.0 g/day for a 60 kg person.…”