Thymus atlanticus polyphenol-rich extract regulates cholesterol metabolism by inhibiting its biosynthesis without affecting its excretion in hamsters fed a high-fat diet.

CONTEXT: Thymus atlanticus has been reported to have significant hypolipidaemic effect in animal models. However, the mechanism of this hypolipidaemic action still unknown. OBJECTIVE: To determinate the possible mechanism(s) of hypolipidaemic action of a Thymus atlanticus polyphenol-rich extract (PRE). MATERIALS AND METHODS: Plasma, faecal, and liver cholesterol, bile acid content in the faeces, and gene expression level of HMG-CoA reductase, CYP7A1, ABCG5 and ABCG8 were analysed after 9 weeks in hamsters feeding normal diet, high-fat diet (HFD) or HFD supplemented with 400 mg/kg body weight/day of PRE. RESULTS: PRE significantly decreased total cholesterol content (p < .05) and HMG-CoA reductase expression (p < .05), but did not affect the faecal cholesterol, bile acid contents and CYP7A1 and ABCG5/G8 expression (p > .05). CONCLUSION: We can conclude that the T. atlanticus extract is efficient in the alleviation of chronic hyperlipidaemia by acting as cholesterol biosynthesis inhibitor.

Loquat (Eriobotrya japonica (Thunb) Lindl.): Evaluation of nutritional value, polyphenol composition, antidiabetic effect, and toxicity of leaf aqueous extract.

ETHNOPHARMACOLOGICAL RELEVANCE: Loquat (Eriobotrya japonica (Thunb.) Lindl.) is an evergreen tree native to China, which is introduced in many Mediterranean countries. As in many ancient medical systems, loquat leaves have been used in Moroccan traditional medicine to treat diabetes and its complications. AIM OF THE STUDY: This study aims to determine the nutritional and polyphenol composition and to evaluate the in vivo antidiabetic, and antihyperlipidemic properties and oral toxicity of a leaf aqueous extract (LLE) derived from loquat grown in Morocco. MATERIALS AND METHODS: Energy value and fiber, fatty acids, minerals, vitamins, total carbohydrate, sugar, lipid, and protein contents were determined according to international methods committee guidelines. Polyphenol profiling was carried out using the HPLC-DAD method. Mice fed a high-fat and high-glucose (HFG) diet for 10 weeks were used as a model to assess the antidiabetic and antihyperlipidemic effects of a daily administration of LLE at three different doses (150, 200, 250 mg/kg body weight (BW)/day), in comparison with metformin (50 mg/kg BW/day) and pravastatin (20 mg/kg BW/day). The oral toxicity was determined following OECD 425 Guideline. RESULTS: Loquat leaves were found to be rich in fiber, minerals (potassium, calcium, magnesium, iron, and sodium), and vitamins (B2, B6, and B12) and lower in energy, sugar, and fat. Ten different phenolic compounds were characterized. Naringenin, procyanidin C1, epicatechin, and rutin were the more abundant compounds in LLE. The administration of the LLE dose-dependently ameliorated hyperglycemia, insulin resistance, oxidative stress, and hyperlipidemia in HFG diet-fed mice. The median lethal dose of LLE was higher than 5000 mg/kg BW. CONCLUSIONS: Loquat leaves are a potential source of micronutrients and polyphenols with beneficial effects on diabetes and its complications.

Effect of supplementation with polyphenol extract of Thymus atlanticus on paraoxonase-1 activity, insulin resistance, and lipid profile in high-fat diet-fed hamsters.

Thymus atlanticus has been used by Moroccan people to treat a variety of health problems, particularly metabolic disorders. In this study, hamsters fed a high-fat diet daily received distilled water (a positive control) or a single dose of Thymus atlanticus polyphenols (Pp) for 63 days. The negative control was fed a normal diet and received distilled water. Results showed that the supplementation of HFD with Pp significantly (p < .001) reduced the levels of MDA and LDL cholesterol, restored insulin level, and increased the activities of serum paraoxonase-1 and HDL cholesterol levels, but did not affect (p > .05) the activity of superoxide dismutase and glutathione peroxidase when compared with the group feeding HFD alone. Thymus atlanticus could be an effective agent against dyslipidemia, oxidative stress, and insulin resistance. PRACTICAL APPLICATIONS: HFD consumption is a risk factor for oxidative stress and the development of metabolic disorders, such as hyperlipidemia and insulin resistance, which may result in atherosclerosis and related cardiovascular diseases, the leading causes of death globally. The management of these alterations is an important strategy to prevent and treat heart complications. Our results showed thatT. atlanticus effectively alleviated HFD-induced hyperlipidemia and insulin resistance and improved PON1 activity. T. atlanticus is a source of biomolecules that may be an effective supplement for controlling HFD-related metabolic disorders. Therefore, the findings of this study may be helpful in the preparation of effective supplements from T. atlanticus to control metabolic disorders and related complications.

Protective Effect of Phoenix dactylifera L. Seeds against Paracetamol-Induced Hepatotoxicity in Rats: A Comparison with Vitamin C.

Phoenix dactylifera L. (date palm) seeds have been mentioned in the Moroccan pharmacopoeia as efficient remedies against a wide range of diseases including hepatic and gastrointestinal disorders and countless infections. The current work was performed to assess the phenolic profile and hepatoprotective potential of two date seed varieties, locally known as Jihl and Majhoul, aqueous extracts against paracetamol- (PCM-) driven liver toxicity in 42 Wistar rats. The polyphenol profile was built by means of an HPLC analysis. Hepatic damage was provoked by exposing rats to PCM at a dose of 1.5 g/kg once a week. Besides PCM, Jihl and Majhoul date seed extracts (200 and 400 mg/kg) were administered orally in a day-to-day routine. Our findings showed that among the examined polyphenol compounds, p-coumaric acid, quercetin, caffeic acid, and rutin were the most abundant phytochemicals. Date pits significantly (p < 0.001) stabilized the PCM-driven alterations in liver function parameters (AST, ALT, ALP, LDH, total protein, direct bilirubin, and total bilirubin). Moreover, Phoenix dactylifera pits enhanced considerably (p < 0.001) the activities of antioxidant enzymes (SOD, CAT, and GPx) as well as the level of reduced glutathione (GSH). The established hepatoprotective effect may be due to the date seeds antioxidant effect and their ability to trap free radicals. The main outcomes of the present study could validate the traditional use of these date seeds to manage various health conditions.