Diabetes mellitus is a multifactorial global health disorder that is rising at an alarming rate. Cardiovascular diseases, kidney damage and neuropathy are the main cause of high mortality rates among individuals with diabetes. One effective therapeutic approach for controlling hyperglycemia associated with type-2 diabetes is to target alpha-amylase and alpha-glucosidase, enzymes that catalyzes starch hydrolysis in the intestine. At present, approved inhibitors for these enzymes are restricted to acarbose, miglitol and voglibose. Although these inhibitors retard glucose absorption, undesirable gastrointestinal side effects impede their application. Therefore, research efforts continue to seek novel inhibitors with improved efficacy and minimal side effects. Natural products of plant origin have been a valuable source of therapeutic agents with lesser toxicity and side effects. The anti-diabetic potential through alpha-glucosidase inhibition of plant-derived molecules are summarized in this review. Eight molecules (Taxumariene F, Akebonoic acid, Morusin, Rhaponticin, Procyanidin A2, Alaternin, Mulberrofuran K and Psoralidin) were selected as promising drug candidates and their pharmacokinetic properties and toxicity were discussed where available.

/pdf/a-review-of-alpha-glucosidase-inhibitors-from-plants-as-9ow8o1o38u.pdf

A review of alpha-glucosidase inhibitors from plants as potential candidates for the treatment of type-2 diabetes.

Polygonum multiflorum Thunb. and its processed products have been used in China for centuries due to their multiple beneficial effects to human body. Currently, liver injuries caused by taking P. multiflorum have been reported worldwide, but the potential toxic components and possible mechanism that caused hepatotoxicity remain unclear. It is worth noting that the processing procedure could significantly decrease the toxicity of raw P. multiflorum and the processed products of P. multiflorum are considered to be relatively safe. However, the processing mechanism is still ambiguous, and there is the lack of a scientific approach to control the quality of P. multiflorum praeparata. This study is the first review that summarizes the recently advances (from 2007 to 2017) in the chemical analysis of P. multiflorum, and provides comprehensive information on the quantitative and qualitative analysis of P. multiflorum as well as its related species. In addition, the processing mechanism and quality evaluation of processed P. multiflorum are discussed. Moreover, the toxicity of P. multiflorum is analyzed from the perspectives of exploration of the proposed toxic ingredients, metabolite identification, metabolomics studies, and exogenous contaminant determination. Furthermore, trends and perspectives for future research of this medicine are discussed.

/pdf/polygonum-multiflorum-thunb-a-review-on-chemical-analysis-3nz69w6x8p.pdf

Polygonum multiflorum Thunb.: A Review on Chemical Analysis, Processing Mechanism, Quality Evaluation, and Hepatotoxicity.

Acute toxicity screening of different extractions, components and constituents of Polygonum multiflorum Thunb. on zebrafish (Danio rerio) embryos in vivo.

Popular functional foods and herbs for the management of type-2-diabetes mellitus: A comprehensive review with special reference to clinical trials and its proposed mechanism

The adverse effects of Polygonum (P.) multiflorum, including abnormal bilirubin metabolism, are a serious public health issue. As uridine diphosphate (UDP)-glucuronosyltransferase 1A1 (UGT1A1) is the only enzyme responsible for bilirubin metabolism, we investigated the inhibitory effect of a P. multiflorum extract and 10 anthraquinone and dianthrone compounds on UGT1A1 in rat liver microsomes in vitro. The P. multiflorum extract exhibited the strongest inhibitory effect on UGT1A1 activity (inhibition constant [Ki] = 0.3257 μM, 1422 μg of material/mL), followed by cis-emodin dianthrones (Ki = 0.8630 μM), trans-emodin dianthrones (Ki = 1.083 μM), emodin-8-O-glc (Ki = 3.425 μM), and polygonumnolide C2 (Ki = 4.291 μM). Analysis of the structure–activity relationships of these compounds suggested that the spatial orientation of the molecules and the presence of particular functional groups affect UGT1A1 inhibition. A mechanistic analysis showed that all the tested compounds docked into two of the nine active sites of UGT1A1 and suggested that hydrophobic interactions and hydrogen bonds are important for the affinity of the tested compounds for UGT1A1; moreover, their interaction energies were generally in agreement with the Ki values. These findings provide insight into adverse reactions to P. multiflorum and identify the pharmacophores involved in inhibition of UGT1A1.

/pdf/identification-and-characterization-of-the-structure-3tx94tnvm5.pdf

Identification and characterization of the structure-activity relationships involved in UGT1A1 inhibition by anthraquinone and dianthrone constituents of Polygonum multiflorum.

a-Glucosidase inhibitors extracted from the roots of Polygonum multiflorum Thunb

Seven new dianthrone glycosides, named polygonumnolides A1–B3 (1–7), were isolated from the 70 % EtOH extract of the dried roots of Polygonum multiflorum Thunb. using column chromatography and preparative high-performance liquid chromatography. Their structures were determined by 1D and 2D NMR and mass spectroscopy. The isolated compounds were evaluated for their cytotoxic effects against KB tumor cell lines and compounds 1–4 showed moderate cytotoxicity.

/pdf/polygonumnolides-a1-b3-minor-dianthrone-derivatives-from-the-4hob3v8hxa.pdf

Zhong Dai

Papers

a-Glucosidase inhibitors extracted from the roots of Polygonum multiflorum Thunb

Polygonumnolides A1–B3, minor dianthrone derivatives from the roots of Polygonum multiflorum Thunb