Neuroprotective and Anti-Amyloid β Effect and Main Chemical Profiles of White Tea: Comparison Against Green, Oolong and Black Tea

Abstract

White tea (WT) is one of six tea types originally derived from Fujian Province, China. White tea is known for its health-promoting properties. However, the neuroprotective and anti-aggregatory properties of WT against the hallmark toxic Alzheimer’s protein, Aβ have not been investigated. In this study, WT, green tea (GT), oolong tea (OT) and black tea (BT) were manufactured using tea leaves from the cultivar Camellia sinensis (Jin Guanyin). The protective effects of these tea extracts were then studied under oxidative stress conditions via t-bhp and H2O2 exposure, in addition to Aβ treatment using a PC-12 cell model. Each tea type failed to rescue PC-12 cells from either t-bhp or H2O2-mediated toxicity, however each extract exerted significant protection against Aβ-evoked neurotoxicity. Results of the Thioflavin T Kinetic (ThT) and TEM assay showed that Aβ aggregate formation was inhibited by each tea type. Additionally, TEM also supported the different anti-aggregatory effect of WT by modifying Aβ into an amorphous and punctate aggregate morphology. Higher accumulated precedent or potential neuroprotective compounds in WT, including ECG’’3Me, 8-C-ascorbyl-EGCG, GABA and Gln, in addition to flavonol or flavone glycosides detected by using UPLC-QTOF-MS and UPLC-QqQ-MS, may contribute to a favourable anti-aggregative and neuroprotective effect of WT against Aβ.

Green and white teas as health-promoting foods

“…Acute lung injury or acute respiratory distress syndrome are serious clinical complications with high morbidity and mortality. 95 A study in mice showed that treatment with EGCG improved histopathological lesions, reduced pro-inflammatory markers and improved lung regeneration capacity by improving the expression of Ki67, PCNA and Ang-1 proteins. 95…”

Extract from the Marine Seaweed Padina pavonica Protects Mitochondrial Biomembranes from Damage by Amyloidogenic Peptides

“…We observed that 1 μg/mL PPE exerted a highly significant reduction in both Aβ- and α-syn-induced CCR from mitochondria (Aβ42: from 2.24 ng/mL to 0.61 ng/mL, p < 0.001; α-syn: from 2.95 ng/mL to 1.43 ng/mL, p < 0.001). The inhibition by PPE was compared to that of black tea extract (BTE) as a ‘positive control’, since BTE is a well-known anti-amyloid and neuroprotectant against both Aβ and α-syn toxicity in vitro and in vivo [ 35 , 36 , 37 ]. Indeed, PPE was similarly effective to BTE in preventing CCR, especially against Aβ ( Figure 1 A,B).…”

Nanostructures Formed by Custom-Made Peptides Based on Amyloid Peptide Sequences and Their Inhibition by 2-Hydroxynaphthoquinone

“…The inhibitory investigations of amyloid aggregation usually employ transmission electron microscopy to visualize the effects of inhibitors at molecular level as applied in many studies (Bermejo-Bescos et al, 2010 ; Gong et al, 2014 ; Li et al, 2019 ; Scheidt et al, 2019 ). In this study, we co-incubated the amyloid peptides with HNQ (peptide: HNQ concentration = 8:1) for 3 days and took SEM images of treated samples.…”

“…The mesh of fibers in peptide P3 incubated with HNQ disappeared ( Figure 1B ) as has been observed in similar studies on inhibitor action of 1,4-naphthoquinones (Gill, 2014 ), quinones (Gong et al, 2014 ), and other polyphenols (Ono et al, 2003 ), and copper (Mold et al, 2013 ) on amyloid formations. Amyloid β treated with white tea also showed amorphous aggregates whereas the overall density of aggregates was less in those samples treated with other types of tea (Li et al, 2019 ). Tubular aggregates of P3 appear to have dissolved as has been observed when amyloid aggregates were treated with curcumin (Yang et al, 2005 ).…”