Hypoglycemic and antihyperglycemic effect of Witheringia solanacea in normal and alloxan-induced hyperglycemic rats

Anil Kumar N, Sharopov F, Ramírez-Alarcón K, Ruiz-Ortega A, Abdulmajid Ayatollahi S, Valere Tsouh Fokou P, Kobarfard F, Amiruddin Zakaria Z, Iriti M, Taheri Y, Martorell M, Sureda A, N. Setzer W, Durazzo A, Lucarini M, Santini A, Capasso R, Adrian Ostrander E, -ur-Rahman A, Iqbal Choudhary M, C. Cho W, Sharifi-Rad J. Antidiabetic Potential of Medicinal Plants and Their Active Components

Diabetes mellitus is one of the major health problems in the world, the incidence and associated mortality are increasing. Inadequate regulation of the blood sugar imposes serious consequences for health. Conventional antidiabetic drugs are effective, however, also with unavoidable side effects. On the other hand, medicinal plants may act as an alternative source of antidiabetic agents. Examples of medicinal plants with antidiabetic potential are described, with focuses on preclinical and clinical studies. The beneficial potential of each plant matrix is given by the combined and concerted action of their profile of biologically active compounds.

Chemical and Biological Aspects of Extracts from Medicinal Plants with Antidiabetic Effects

Diabetes mellitus is a chronic disease and a leading cause of death in western countries. Despite advancements in the clinical management of the disease, it is not possible to control the late complications of diabetes. The main characteristic feature of diabetes is hyperglycemia, which reflects the deterioration in the use of glucose due to a faulty or poor response to insulin secretion. Alloxan and streptozotocin (STZ) are the chemical tools that are most commonly used to study the disease in rodents. Many plant species have been used in ethnopharmacology or to treat experimentally symptoms of this disease. When evaluated pharmacologically, most of the plants employed as antidiabetic substances have been shown to exhibit hypoglycemic and antihyperglycemic activities, and to contain chemical constituents that may be used as new antidiabetic agents. There are many substances extracted from plants that offer antidiabetic potential, whereas others may result in hypoglycemia as a side effect due to their toxicity, particularly their hepatotoxicity. In this article we present an updated overview of the studies on extracts from medicinal plants, relating the mechanisms of action by which these substances act and the natural principles of antidiabetic activity.

Evaluation of hypoglycemic effects of polyphenols and extracts from Penthorum chinense

ETHNOPHARMACOLOGICAL RELEVANCE

Penthorum chinense Pursh has a long history of use as a health food and folk medicine to alleviate "heat"-associated disorders, promote circulation and diuresis, and to treat liver problems, and to protect the spleen. In this study we provide experimental evidence for the clinical use of Penthorum chinense in the treatment of diabetes mellitus. The aim of the study was to investigate the hypoglycemic effects of extracts and active constituents from Penthorum chinense.

MATERIALS AND METHODS

High fat diet and STZ (35mg/kg) induced diabetic rats were administered with Penthorum chinense extract at graded oral doses (150 and 300mg/kg/day, ig.) for 2 weeks. A range of parameters, including blood glucose and lipid, serum insulin, glucose tolerance, were tested to evaluate its anti-hyperglycemic effects. Moreover, oral starch tolerance test (OSTT) was performed to test the level of postprandial glucose after administrating Penthorum chinense extract. In vitro study, the Penthorum chinense extracts and purified Penthorum chinense polyphenols were tested for α-amylase inhibitory activity. The polyphenols were determined by UPLC-Q-TOF mass spectrometry and NMR.

RESULTS

The Penthorum chinense extract possessed anti-hyperglycemic activities as shown by the decreased serum levels of glycosylated hemoglobulin A1C (HbA1c), triglyceride(TG), total cholesterol (TC), and low density lipoprotein-cholesterol (LDL-C), as well as increased serum levels of high density lipoprotein-cholesterol (HDL-C) and insulin. Penthorum chinense extract also improved the oral glucose tolerance test (OGTT) to a certain degree. Moreover, the OSTT study showed that in diabetic rats, the extract (600mg/kg) caused a significant hypoglycemic effect with a blood glucose reduction of 42% at 60min. To identify the active constituents, three polyphenols, pinocembrin-7-O-[4″,6″-hexahydroxydiphenoyl]-β-d-glucose (1), pinocembrin-7-O-[3″-O-galloyl-4″, 6″-hexahydroxydiphenoyl]-β- d-glucose (2), and thonningianin A (3) were isolated from Penthorum chinense. Compounds 1-3 moderately inhibited α-amylase activity, with IC50 values of 0.14, 0.03, and 0.08µmol/ml, respectively.

CONCLUSIONS

The folk medicinal plant, Penthorum chinense produced a moderated anti-hyperglycemic effect on STZ-induced diabetic rats and starch induced postprandial hyperglycemic mice.