Obesity is a complicated multifaceted problem generally accompanied by disturbances in carbohydrate and fat metabolism, insulin resistance as well as an increase in oxidative stress. The bark of Hypodaphnis zenkeri (HZ) and dry fruits of Xylopia aethiopica (XA) commonly used as spices in Cameroonian cuisine also have applications in traditional medicine. This study evaluates their effects on some biological parameters of acute hyperlipidemic rats and on rats fed with High Fat High Sucrose (HFHS) diet. The spices were extracted in water, water/ethanol (50/50) and ethanol. The first part of the work was the in vitro study where, the partial phytochemical composition as well as the antioxidant potential of extracts were studied, using folin Ciocalteu's phenol method and ABTS (3-ethyl-benzothiazoline-6-sulfonic acid) assay. The best extract for each spice was selected and used for the "in vivo" study which consisted in studying their effect on weight and biochemical parameters in acute hyperlipidemic rats and insulin resistant rats. The extracts contained phenols like flavonoids. They also showed free radical scavenging properties in vitro. Total phenolic content were higher particularly for the hydroethanolic extract (HEE) of Hypodaphnis zenkeri (413.87 ± 13.19 mg Eq catechin/g of extract), but lowest for the water extract (WE) of Xylopia aethiopica (63.07 ± 1.60 mg Eq catechin/g of extract). At a concentration of 400 mg/kg, the HEE extract of Hypodaphnis zenkeri showed a hypotriglyceridemic activity on rats with hypertriglyceridemia induced by triton WR-1339 unlike the EE of Xylopia aethiopica. But these two extracts inhibited weight gain and reduced postprandial glycemia in insulin resistant rats. The bark of Hypodaphnis zenkeri, and dry fruits of Xylopia aethiopica contained bioactive ingredients; they ameliorated the glucose uptake and the evolution of weight impaired by the chronic consumption of HFHS diet in rats.
The study of edible plants, especially in developing countries, might provide more affordable means for the management of diabetes. Telfairia occidentalis is one of the plants whose leaves are commonly consumed in Cameroon. This work hereby studied the antiamylasic potential of its aqueous leaves extract and the effect of its dietary supplementation on fasting blood glucose in Wistar rats. An aqueous extract (1:6) was prepared from shed-dried T. occidentalis leaves by maceration. Its antiamylase activity was evaluated in vitro and a phytochemical screening was realized. Its acute toxicity and its effect on an oral glucose tolerance test (OGTT) were evaluated in rats. The effect of T. occidentalis leaves dietary supplementation (10%) on fasting blood glucose was studied for 28 days in rats fed with carbohydrate enriched diet, using Glibenclamide (0.3 mg/kg body weight) as reference hypoglycemic drug. Results showed that there was total inhibition of α-amylase activity in vitro by T. occidentalis aqueous leaves extract at 0.075 mg/ml. The presence of tannins, flavonoids and anthocyanins was revealed by the phytochemical screening. No sign of toxicity was observed in rats after an oral administration of the extract at 2000 mg/kg body weight. The extract significantly hindered a rise in blood glucose at 400 mg/kg body weight during an oral glucose tolerance test. Dietary supplementation with T. occidentalis leaves caused a significant decrease (p < 0.05) in fasting blood glucose as compared to the positive control. Telfairia occidentalis leaves and their aqueous extract could be used in the management of hyperglycemia and diabetes.
Edible mushrooms, known for many years and considered as functional foods, contain a wide variety of biomolecules with nutritional and medicinal properties. Pleurotus species, especially Pleurotus pulmonarius, Pleurotus floridanus and Pleurotus sajor-caju are the most commonly consumed in Cameroon. The present work aims to study the "in vitro" antiradical activity and ferric reducing antioxidant power of extracts of formulations of these three species. Mushrooms were harvested in two mycicultures from Cameroon, then dried and crushed finely to obtain powders. In well-defined proportions, ten different formulations were made and their aqueous, ethanol and hydroethanol extracts prepared. These were used to determine total phenolic content by using Folin-Ciocalteu reagent method, the antioxidant activity determined by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity and ferric-reducing antioxidant power (FRAP) assays, with vitamin C (ascorbic acid) as standard. The results obtained from the ten formulations, including thirty extracts, showed that all the extracts had quite significant ferric reducing power at C = 1 mg/ml, (7.35-26.02 mg EAA/g). They also had good percentages of DPPH radical inhibition at C = 25 mg/ml (60.40%-77.72%) and a significant polyphenol content at C = 100 mg/ml (13.73-21.15 mg CE/g). The aqueous extracts had the best activities compared to the standard. In addition, a strong positive linear correlation exists between polyphenol content and the scavenging property (R 2 = 0.9063; p = 0.0003) also with the ferric reducing test (R 2 = 0.9253; p = 0.0001); suggesting the responsibility of these compounds for these activities. This study suggests that these mushrooms may be used as a natural source of potential antioxidants for food supplements and their consumption is strongly recommended How to cite this paper:
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