In vitro evaluation of the protective effects of plant extracts against amyloid-beta peptide-induced toxicity in human neuroblastoma SH-SY5Y cells

Abstract

Alzheimer’s disease (AD) is the most common form of dementia and has no cure. Therapeutic strategies focusing on the reduction of oxidative stress, modulation of amyloid-beta (Aβ) toxicity and inhibition of tau protein hyperphosphorylation are warranted to avoid the development and progression of AD. The aim of this study was to screen the crude extracts (CEs) and ethyl-acetate fractions (EAFs) of Guazuma ulmifolia , Limonium brasiliense , Paullinia cupana , Poincianella pluviosa , Stryphnodendron adstringens and Trichilia catigua using preliminary in vitro bioassays (acetylcholinesterase inhibition, antioxidant activity and total polyphenol content) to select extracts/fractions and assess their protective effects against Aβ 25–35 toxicity in SH-SY5Y cells. The effect of the EAF of S . adstringens on mitochondrial membrane potential, lipid peroxidation, superoxide production and mRNA expression of 10 genes related to AD was also evaluated and the electropherogram fingerprints of EAFs were established by capillary electrophoresis. Chemometric tools were used to correlate the in vitro activities of the samples with their potential to be evaluated against AD and to divide extracts/fractions into four clusters. Pretreatment with the EAFs grouped in cluster 1 ( S . adstringens , P . pluviosa and L . brasiliense ) protected SH-SY5Y cells from Aβ 25-35 -induced toxicity. The EAF of S . adstringens at 15.62 μg/mL was able completely to inhibit the mitochondrial depolarization (69%), superoxide production (49%) and Aβ 25-35 -induced lipid peroxidation (35%). With respect to mRNA expression, the EAF of S . adstringens also prevented the MAPT mRNA overexpression (expression ratio of 2.387x) induced by Aβ 25–35 , which may be related to tau protein hyperphosphorylation. This is the first time that the neuroprotective effects of these fractions have been demonstrated and that the electropherogram fingerprints for the EAFs of G . ulmifolia , L . brasiliense , P . cupana , P . pluviosa and S . adstringens have been established. The study expands knowledge of the in vitro protective effects and quality control of the evaluated fractions.

In Vivo Anti Cancer Potential of Pyrogallol in Murine Model of Colon Cancer

“…However, it has been suggested that inhibition of H. pylori induced gastric inflammation associated with oxidative stress is considered as one of the promising approaches to prevent carcinogenesis (Cao et al, 2007). This statement is in agreement with our results where pyrogallol is an antioxidant (Kang et al, 2011;Li, 2012) and reported to be an anti tumor agent in breast cancer and neuroblastoma model (Nemec et al, 2016;Sereia et al, 2019). Our current data suggests that anti colon tumor efficacy of pyrogallol could be due to scavenging of free radicals produced by H. pylori induced inflammation associated carcinogenesis in mice.…”

Antioxidant Activity of Flavonoid Rich Fraction of Ligaria cuneifolia (Loranthaceae)

“…The CD-MEKC methodology present several advantages over traditional chromatographic approaches. [36,37] Not only does it allow a rapid flavonoid fingerprinting of the extract, but also enables the evaluation of the antioxidant capacity of each compound upon the reaction with DPPH * in the context of the whole plant extract, considering the potential synergy and antagonism among flavonoids. Consequently, this approach most closely resembles what actually takes place in a real sample when tested as an antioxidant.…”

A Mechanistic Evaluation of Antioxidant Nutraceuticals on Their Potential against Age-Associated Neurodegenerative Diseases

“…It contains very high levels of caffeine as well as polyphenols such as catechins and epicatechins [ 103 ]. Recently, in vitro antioxidant assay done on a variety of Brazilian herb extracts, including from guarana seeds, have been reported [ 104 ]. Moreover, the antioxidant and anti-ageing potential of guarana seed, together with its protective effect on neurodegenerative diseases, has been well documented [ 105 , 106 , 107 ].…”