A Narrative Review of Human Clinical Trials on the Impact of Phenolic-Rich Plant Extracts on Prediabetes and Its Subgroups

Abstract

Phenolic-rich plant extracts have been demonstrated to improve glycemic control in individuals with prediabetes. However, there is increasing evidence that people with prediabetes are not a homogeneous group but exhibit different glycemic profiles leading to the existence of prediabetes subgroups. Prediabetes subgroups have been identified as: isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT), and combined impaired fasting glucose and glucose intolerance (IFG/IGT). The present review investigates human clinical trials examining the hypoglycemic potential of phenolic-rich plant extracts in prediabetes and prediabetes subgroups. Artemisia princeps Pampanini, soy (Glycine max (L.) Merrill) leaf and Citrus junos Tanaka peel have been demonstrated to improve fasting glycemia and thus may be more useful for individuals with IFG with increasing hepatic insulin resistance. In contrast, white mulberry (Morus alba Linn.) leaf, persimmon (Diospyros kaki) leaf and Acacia. Mearnsii bark were shown to improve postprandial glycemia and hence may be preferably beneficial for individuals with IGT with increasing muscle insulin resistance. Elaeis guineensis leaf was observed to improve both fasting and postprandial glycemic measures depending on the dose. Current evidence remains scarce regarding the impact of the plant extracts on glycemic control in prediabetes subgroups and therefore warrants further study.

Investigation of the Renal Protective Effect of Combined Dietary Polyphenols in Streptozotocin-Induced Diabetic Aged Rats

“…Moreover, polyphenols consumption was also advised as a cure for patients undergoing dialysis in hospital service [ 70 ] and for those who are increasingly prescribed clinical treatment for kidney disease and renal fibrosis [ 69 , 71 , 72 ]. Despite the large heterogeneity of the chronic kidney disease patients, including the genetic and the behavior causes, food polyphenols present as a large spectrum and safe drugs complements as demonstrated with the increase of human clinical trials in the recent years [ 73 ]. However, this tendency should be better supervised and huge research effort is still needed to avoid any excess or uncalculated synergy that could occur before clinical approval, especially due to the critical pharmacokinetics and extensive metabolization that polyphenols undergo in the human body [ 66 ].…”

A Pilot Study on the Glucose-Lowering Effects of a Nutritional Supplement in People with Prediabetes

“…Moreover, in an in vitro study among 40 extracts, C. creticus extract proved to have the highest inhibitory activity on aldose reductase, the key enzyme of the polyol pathway [30]. Plant extracts rich in phenolics have been studied for the improvement of hyperglycemia in individuals with prediabetes, providing the opportunity for their use as alternative or complementary treatments with few or no adverse effects [31]. In the present study, we used a nutritional supplement that combines two rich polyphenol plant extracts, purslane and pink rock rose, which have an insulin-mimetic action, together with vitamins and minerals, with proven beneficial actions on the maintenance of glucose homeostasis.…”

Natural flavonoids derived from herbal medicines are potential anti-atherogenic agents by inhibiting oxidative stress in endothelial cells

“…Artemisia princeps Pampanini has been widely used as a medicinal plant in Asia over the last thousands of years. In modern times, due to the rapid development of modern pharmacology, eupatilin has been found to have a wider range of pharmacological activities (Lim et al, 2021). For example, eupatilin has therapeutic potential in diseases such as oncology, allergy, and inflammation (Park, 2014;Jeong et al, 2015).…”