Herbal Medicines and Nutraceuticals for Diabetic Vascular Complications: Mechanisms of Action and Bioactive Phytochemicals

Eshaifol      A. Omar; Antony      Kam; Ali      Alqahtani; Kong      M. Li; Valentina      Razmovski-Naumovski; Srinivas      Nammi; Kelvin      Chan; Basil      D Roufogalis; George      Q. Li

Abstract

Diabetes is one of the most prevalent chronic diseases throughout the world. The majority of its complications arise from vascular-related inflammation apparently initiated by endothelial cell injury. One cause of this injury has been attributed to hyperglycaemia-induced reactive oxygen species. Consequently, current drug developmental strategy has targeted specific inflammatory and oxidative stress pathways for the prevention of diabetic vascular complications. Herbal medicines have traditionally been used for the treatment of diabetes and its complications. In fact, current pre-clinical and clinical studies have demonstrated that many of them exhibit potent anti-inflammatory and anti-oxidative properties, and have also identified the active phytochemicals responsible for their activities. The present review summarises the latest research on the molecular mechanisms of diabetic vascular complications, and evaluates the level of scientific evidence for common herbal medicines and their bioactive phytochemicals. These agents have been shown to be effective through various mechanisms, particularly the NF-κB signalling pathways. Overall, herbal medicines and nutraceuticals, as well as their bioactive components, which exhibit anti-inflammatory and anti-oxidative properties, provide a promising approach for the prevention and treatment of diabetic complications.

Keywords: Anti-oxidants, diabetic complications, herbal medicines, inflammation, mechanisms of action, nutraceuticals, phytochemicals, hyperglycaemia, ROS, peripheral nervous system, meta-bolic syndrome, syndrome X, renal-related complications, ketoacidosis, retinopathy, limb ischemia, pancreatic insulin secretion, insulin sensitivity, peripheral glucose utilization, sulfonylurea, hiazolidinediones, biguanides, alpha-glucosidase inhibitors, insu-lin-like growth factor, incretin mimetics, aminoguanidine, alagebrium, benfotiamine, ruboxis-taurin, oxidative stress, protein kinase C (PKC), polyol/aldose reductase, (AGE), –, receptor of AGE (RAGE) pathways, protein-1 (AP-1), mitogen-activated protein kinases (MAPK), nuclear factor-kappa B (NF-B), inflammatory cytokines, TNF, IL-1, IL-6, IB kinase (IKK), IKK, nitric oxide synthase (iNOS), VCAM-I, ICAM, chemokines (e.g. MCP-1), Paeonia suffruticosa, Crataegus pinnatifida, Cinnamonum, Ligusticum chuangxiong, Salvia miltiorrhiza, Carthamus tinctoris, Dalbergia odorifera, Angelica sinensis, Cimicifuga heracleifolia, Gynostemma pentaphyllum