Abstract
Diabetic neuropathy (DN) is a serious complication in type-1 diabetes and
type-2 diabetes. Animal models show many abnormalities like neuropathy,
hyperalgesia, allodynia, slow nerve conduction velocity (NCV), and progressive
sensory and motor deficit that are associated with diabetic neuropathy. Various risk
factors may be involved in causing DN, such as persistent hyperglycemia,
microvascular insufficiency, oxidative stress, nitrosative stress, defective
neurotrophism and autoimmune-mediated nerve destruction. Many conventional and
newer therapeutic approaches are available. Approaches include effective control of
glycemia. Symptoms targeted therapies such as antidepressants, SSRIs,
anticonvulsants, opiates, NSAIDs and NMDA receptor antagonists. Therapies targeting
particular causes include aldose reductase inhibitors, drugs that act on hexosamine
pathways, protein kinase C pathways and AGE receptors. Preclinical studies involving
pharmacological agents have shown positive results but were withdrawn at the stage of
a clinical study, either due to lack of efficacy or due to their side effects on major
organs. Medicinal herbal plants are the richest bio-resource of drugs that have been
studied extensively for their neuroprotective effects. Various approaches involving
neuroprotection by natural products are discussed here.