Theacrine, a purine alkaloid from kucha, protects against Parkinson's disease through SIRT3 activation.

BACKGROUND: Oxidative damage of dopaminergic neurons is the fundamental causes of Parkinson's disease (PD) that has no standard cure at present. Theacrine, a purine alkaloid from Chinese tea Kucha, has been speculated to benefit the neurodegeneration in PD, through similar actions to its chemical analogue caffeine, albeit excluding side effects. Theacrine has nowadays gained a lot of interest for its multiple benefits, while the investigations are weak and insufficient. HYPOTHESIS/PURPOSE: It is well-known that tea has a wide range of functions, especially in the prevention and treatment of neurodegenerative diseases. Theacrine is an active monomer compound in Camellia assamica var. kucha Hung T. Chang & H.S.Wang (Kucha), which appears to be effective and safe in PD therapy. The aim of this study is to examine its actions in diverse PD models and explore the mechanisms. STUDY DESIGN: For determination of theacrine's effects, we employed diverse oxidative damage-associated PD models, including 6-OHDA-treated rats, MPTP-treated mice/zebrafish and MPP+-treated SH-SY5Y cells, and using caffeine, selegiline and depranyl as positve control. For investigation and verification of the mechanisms, we utilized approaches testing mitochondrial function-related parameters and enzyme activity as well as applied gene knockdown and overexpression. METHODS: We employed behavioral tests including spontaneous activity, pole, swimming, rotarod and gait, immunohistochemistry, HPLC, flow cytometry, immunohistochemistry, Western blot, gene knockdown by siRNA and overexpression by plasmid in this study. RESULTS: Theacrine is demonstrated to retrieve the loss of dopaminergic neurons and the damages of behavioral performance in multiple animal models of PD (6-OHDA-treated rats and in MPTP-treated mice and zebrafish). The followed data of MPP+-treated SH-SY5Y cells indicate that theacrine relieves apoptosis resulted from oxidative damage and mitochondrial dysfunction. Further investigations illustrate that theacrine activates SIRT3 directly. It is of advantage to prevent apoptosis through SIRT3-mediated SOD2 deacetylation that reduces ROS accumulation and restores mitochondrial function. This concept is elaborated by 3TYP that inhibits SIRT3 enzyme activity and knockdown/overexpression of SIRT3 gene, demonstrating a crucial role of SIRT3 in theacrine-benefited dopaminergic neurons. CONCLUSION: Theacrine prevents apoptosis of dopaminergic neurons through directly activating SIRT3 which deacetylating SOD2 and restoring mitochondrial functions.

Alternative Oxidase Promotes Biofilm Formation of Candida albicans.

This study was designed to analyze the effect of the mitochondrial respiratory pathways of Candida albicans (C. albicans) on the biofilm formation. The 2, 3-bis (2-methoxy- 4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay was used to measure the metabolic activities of biofilms formed by the C. albicans which were cultured in the presence of respiratory pathways inhibitors. The biofilms formed by the wide type (WT), GOA7-deleted (GOA31), GOAV-reconstituted (GOA32), AOXla-deleted (AOX1) and AOXlb-deleted (AOX2) C. albicans strains were examined by the XTT reduction assay and fluorescence microscopy. The expression of adhesion-related genes BCR1, ALS1, ALS3, ECE1 and HWP1 in the biofilms formed by the above five C. albicans strains was detected by real time polymerase chain reaction. It was found that the metabolic activity of biofilms formed by C. albicans was decreased in the presence of alternative oxidase inhibitor whereas it was increased in the presence of classical mitochondrial respiratory pathway complex HI or complex IV inhibitor. AOX1 strain produced scarce biofilms interspersed with few hyphal filaments. Moreover, no significant changes in the expression of BCR1 and ALS3 were observed in the AOX1 strain, but the expression of ALSI and ECE1 was down-regulated, and that of HWP1 was up-regulated. These results indicate that both AOX1 and AOX2 can promote the biofilm formation. However, AOXla primarily plays a regulatory role in biofilm formation in the absence of inducers where the promoting effect is mainly achieved by promoting mycelial formation.

A comparative analysis of chemical compositions in Camellia sinensis var. puanensis Kurihara, a novel Chinese tea, by HPLC and UFLC-Q-TOF-MS/MS.

Camellia sinensis var. puanensis Kurihara (Puan tea) is a kind of ancient tea plant newly found in Jiangxipo and the surrounding areas of Puan County (Guizhou, China). People there always believe that drinking Puan tea is beneficial to the promotion of health and prevention of diseases. However, detailed information on its compositions has not been reported. Therefore, in this study, the varieties and contents of purine alkaloids and polyphenols in Puan tea were identified and determined by HPLC and UFLC-Q-TOF-MS/MS. Our results showed that theacrine, but not caffeine, was the dominated purine alkaloid detected in Puan tea. Meanwhile, Puan tea contained B-type procyanidin dimer, trimer and dimer monogallate, which were not detected in Camellia sinensis, Camellia ptilophylla and Camellia assamica var. kucha. The obtained results could support the local uses of Puan tea in health and nutrition and contribute to the research of tea variety.