RETRACTED ARTICLE: Polyphenols from Conyza dioscoridis (L.) ameliorate Alzheimer’s disease- like alterations through multi-targeting activities in two animal models

Abstract

Background Recent investigations suggested that anticancer agents may inhibit the progression of Alzheimer's disease (AD) pathology. Conyza dioscoridis (L.) was demonstrated to have anticancer, antioxidant, anti-inflammatory and antidiabetic effects. This study was carried out to investigate the efficacy of polyphenols from Conyza dioscoridis (L.) extract (PCDE) on AD. Methods Impacts of 3 doses of PCDE and donepezil, a reference drug, on the features of Alzheimer's disease in two animal models were investigated. Results PCDE ameliorated the memory and learning impairment shown in rats following a single dose of scopolamine (scopolamine model) or 17 weeks of high-fat/high-fructose(HF/Hfr) diet coupled with a single dose of streptozotocin, (25 mg/kg) (T2D model). They reduced significantly the high hippocampal cholinesterase activity in the two models of rats. Administration of PCDE for 8 weeks in the T2D model showed a significant reduction in hippocampal GSK-3β, caspase-3 activity and increase in the inhibited glutamate receptor expression (AMPA GluR1 subunit and NMDA receptor subunits NR1, NR2A, NR2B). A significant reduction of HOMA-insulin resistance and serum hypercholesterolemia was observed. The Tau hyperphosphorylation and Aβ 1–42 generation in the hippocampal of T2D rats were significantly decreased by PCDE. Modulation of the oxidative stress markers, (rise in GH and SOD; decrease in MDA levels) and a significant reduction of TNF-α and IL-1β in the hippocampus of T2D rats treated by PCDE extract were important findings in this study. The highest dose tested was 4% of the highest safe dose. Conclusion Our study suggests that PCDE is multi-targeting agent with multiple beneficial activities in combating features of AD. This study may provide a novel therapeutic strategy for AD treatment that warrants clinical studies.

Oligonol ameliorates liver function and brain function in the 5 × FAD mouse model: transcriptional and cellular analysis

“…18 Quercetin, a well-known flavonoid obtained from red berries, grapes, and onions, can increase mitochondrial biogenesis in neurons and protect neuronal cells against oxidative stress-induced free radicals. 19 In addition, polyphenols obtained from conyza dioscoridis are known to attenuate AD pathologies, 20 while others from resveratrol have been shown to enhance memory deficit in an AD mouse model. 21…”

“…18 Quercetin, a well-known flavonoid obtained from red berries, grapes, and onions, can increase mitochondrial biogenesis in neurons and protect neuronal cells against oxidative stress-induced free radicals. 19 In addition, polyphe-nols obtained from conyza dioscoridis are known to attenuate AD pathologies, 20 while others from resveratrol have been shown to enhance memory deficit in an AD mouse model. 21 Recently, oligonol, a low-molecular-weight polyphenol derived from lychee fruit extract and containing catechin-type monomers and pro-anthocyanidin oligomers, has gained interest owing to its potential to attenuate cognition impairment in AD and aging models.…”