ABSTRACT
BACKGROUND: The formation of senile plaques and neurofibrillary tangles of the tau protein are the main pathological mechanism of Alzheimer's disease (AD). Current therapies for AD offer discrete benefits to the clinical symptoms and do not prevent the continuing degeneration of neuronal cells. Therefore, novel therapeutic strategies have long been investigated, where curcumin (Curcuma longa) has shown some properties that can prevent the deleterious processes involved in neurodegenerative diseases. OBJECTIVE: The aim of the present work is to review studies that addressed the effects of curcumin in experimental models (in vivo and in vitro) for AD. METHOD: This study is a systematic review conducted between January and June 2017, in which a consultation of scientific articles from indexed periodicals was carried out in Science Direct, United States National Library of Medicine (PubMed), Cochrane Library and Scielo databases, using the following descriptors: "Curcuma longa", "Curcumin" and "Alzheimer's disease". RESULTS: A total of 32 studies were analyzed, which indicated that curcumin supplementation reverses neurotoxic and behavioral damages in both in vivo and in vitro models of AD. CONCLUSION: The administration of curcumin in experimental models seems to be a promising approach in AD, even though it is suggested that additional studies must be conducted using distinct doses and through other routes of administration.
Subject(s)
Alzheimer Disease/drug therapy , Curcumin/administration & dosage , Neuroprotective Agents/administration & dosage , Plant Extracts/administration & dosage , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Alzheimer Disease/prevention & control , Amyloid beta-Peptides/metabolism , Animals , Curcuma/chemistry , Curcumin/pharmacology , Dietary Supplements , Humans , Neurofibrillary Tangles/metabolism , Neuroprotective Agents/pharmacology , Plant Extracts/pharmacology , Randomized Controlled Trials as TopicABSTRACT
Parkinson's disease (PD) consists of a neurodegenerative pathology that has received a considerable amount of attention because of its clinical manifestations. The most common treatment consists of administering the drugs levodopa and biperiden, which reduce the effectiveness of the disease and the progress of its symptoms. However, phytotherapy treatment of PD has shown great potential in retarding the loss of dopaminergic neurons and minimizing the behavioral abnormalities. The aim of this study is to systematically review the use of supplemental herbal plants with cellular protective effect and behavioral activity in in vivo and in vitro experimental models. A total of 20 studies were summarized, where the effectiveness of herbal extracts and their isolated bioactive compounds was observed in animal models for PD. The main neurochemical mechanisms found in these studies are schematically represented. The herbal extracts and their biocompounds have antioxidant, anti-apoptotic, and antiinflammatory properties, which contribute to avoiding neuronal loss. Reports show that besides acting on the biosynthesis of dopamine and its metabolites, these compounds prevent D2 receptors' hypersensitivity. It is suggested that further studies need be conducted to better understand the mechanisms of action of the bioactive compounds distributed in these plants. Copyright © 2017 John Wiley & Sons, Ltd.
