Tapinanthus dodoneifolius leaf inhibits the activity of carbohydrate digesting enzymes and improves the insulin resistance induced in rats by dexamethasone

Background

Tapinanthus dodoneifolius is a plant used in traditional African medicine to treat diabetes mellitus. This study aimed to evaluate the preventive antidiabetic potential of the aqueous extract of T. dodoneifolius leaves (AETD) in insulin resistant rats.

Methods

A quantitative phytochemical study of AETD was carried out to determine the contents of total phenols, tannins, flavonoids, and saponins. AETD was tested in vitro on the activity of α-amylase and α-glucosidase enzymes. Insulin resistance was induced for 10 days by daily subcutaneous injection of dexamethasone (1 mg/kg). One hour before, the rats were divided into 5 groups and treated as follows: group 1 received distilled water (10 mL/kg); group 2 received metformin (40 mg/kg), and groups 3, 4, and 5 were treated with AETD (125, 250, and 500 mg/kg). Body weight, blood sugar, food and water consumption, serum insulin level, lipid profile, and oxidative status were assessed. One-way analysis of variance followed by Turkey's post-test and two-way analysis followed by Bonferroni's post-test were used to analyze univariate and bivariate parameters, respectively.

Results

Results showed that the phenol content of AETD (54.13 ± 0.14 mg GAE/g extract) was higher than that of flavonoids (16.73 ± 0.06 mg GAE/g extract), tannins (12.08 ± 0.07 mg GAE/g extract), and saponins (IC₅₀ = 13.56 ± 0.03 mg DE/g extract). AETD showed a higher inhibitory potential on α-glucosidase activity (IC₅₀ = 191.51 ± 5.63 μg/mL) than on α-amylase activity (IC₅₀ = 1774.90 ± 10.32 μg/mL). AETD (250 and/or 500 mg/kg) prevented drastic loss of body weight and reduced food and water consumption in insulin resistant rats. The levels of blood glucose, total cholesterol, triglycerides, low-density lipoprotein cholesterol, and malondialdehyde were also reduced while high-density lipoprotein cholesterol level, reduced glutathion level, and catalase and superoxide dismutase activity increased after administration of AETD (250 and 500 mg/kg) in insulin resistant rats.

Conclusion

AETD has significant antihyperglycemic, antidyslipidemic, and antioxidant potential, thus it can be used for the management of type 2 diabetes mellitus and its complications.

Antioxidant activity and phytochemical constituent of two plants used to manage foot and mouth disease in the Far North Region of Cameroon

Aim:

Plants used in the Far North Region of Cameroon by livestock farmers to manage foot and mouth disease (FMD) in cattle and the phytochemical composition and antioxidant potentials of two of them (Boscia senegalensis [BS] and Tapinanthus dodoneifolius [TD]) were investigated in this study.

Materials and Methods:

Ethno veterinary data were collected from 325 livestock farmers using semi-structured interviews from September 2011 to April 2012. The 2,2-diphenyl-picrylhydrazyl radical scavenging activity and total phenolic content (TPC) were first performed with five different solvents to choose the best extract of each plant based on these two factors. To achieve our aim, the ferric iron reducing activity, hydroxyl radical scavenging activity (HRSA), free radical scavenging activity (FRSA), vitamin E and iron content were analyzed on extracts selected using current techniques.

Results:

The results showed that 12 plants of 8 different families are regularly used by farmers to manage FMD. It also demonstrated that acetone extract of TD and methanolic extract of BS are the extracts which showed the best total antioxidant activity (AA) and the best TPC. In general, TD show the best AA during the HRSA and FRSA analysis compared with BS. Similarly, TD content more phenolic compounds and tannins than BS. Both plants contain proteins, saponins, tannins, phenols, alkaloid, and polyphenols which are known to have many biological activities.

Conclusion:

These results support the AA of both plants and can justify their use by herders to treat FMD which is often followed by many secondary diseases.