Role of natural products in alleviation of Huntington's disease: An overview

Huntington's disease (HD) is an autosomal cognitive impairment neurodegenerative disorder that is characterized by behavioral and psychiatric disorders followed by dementia. HD is caused by repeated expansion of cytosine-adenine-guanine trinucleotide within the Huntingtin gene (Htt), which encodes for polyglutamine repeat in Huntingtin protein (Htt). Although a number of conventional treatment options such as antipsychotic drugs, antidepressants, mood stabilizing agents, anti-anxiety drugs and omega fatty acids are available for HD but all of them are associated with one or more side effects. Herbal products are an alternative remedies used for treatment of diverse pathological conditions are comparatively safe as compared to synthetic molecules. The present review summarizes various clinical and preclinical studies involving phytoconstituents which have been explored for treatment of huntington disease. Literature search was conducted using various electronic database i.e Scopus, Google, Pubmed, Web of Science. Search was conducted using different keywords such as “huntignton disease”, “herbal products”, “phytoconstituents”, “antihuntignton botanicals”, “herbal products for huntington disease”, “natural products for huntington disease” and “phytomedicine for huntington disease”. Further studies were screening by assessing abstracts and cross references and previously published review and research articles. A number of natural products are reported with antihuntington effects in various clinical and preclinical studies and some of them are also available as herbal formulations. Prominent phytoconstituents present in different plants exhibiting antihuntington effects include asiatic acid, celastrol, sesamol psoralen, isopsoralen, quercetin, madecassic acid, catechin, kaempferol, charantin, 6-shogoal, ellagic acid, celastrine, bacoside A, ginkgolide B, withaferin A, curcumin, scopoletin, caffeine, β-sitosterol, vitexin, rutin, apigenin, luteolin, cannabidiol, tetrahydrocannabinol, and resveratrol. The plant extracts containing these phytoconstituents or their isolated components are reported to exhibit antihuntington effect by targeting various enzymes, modulating inflammatory mediators and/or by improving cognitive impairment. Although, various preclinical studies have shown promising effects of phytochemicals in treatment of Huntington disease, but further investigation is required to prove their efficacy and safety in human beings.