The Dynamic Change in Fatty Acids during the Postharvest Process of Oolong Tea Production.

As important factors to oolong tea quality, the accumulation and dynamic change in aroma substances attracts great attention. The volatile composition of oolong tea is closely related to the precursor contents. Fatty acids (FAs) and their derivatives are basic components of oolong tea fragrance during the postharvest process. However, information about the precursors of FAs during the postharvest process of oolong tea production is rare. To investigate the transformation of fatty acids during the process of oolong tea production, gas chromatograph−flame ionization detection (GC-FID) was conducted to analyze the composition of FAs. The results show that the content of total polyunsaturated FAs initially increased and then decreased. Specifically, the contents of α-linolenic acid, linoleic acid and other representative substances decreased after the turn-over process of oolong tea production. The results of partial least squares discrimination analysis (PLS-DA) showed that five types of FAs were obviously impacted by the processing methods of oolong tea (VIP > 1.0). LOX (Lipoxygenase, EC 1.13.11.12) is considered one of the key rate-limiting enzymes of long-chain unsaturated FAs in the LOX-HPL (hydroperoxide lyase) pathway, and the mechanical wounding occurring during the postharvest process of oolong tea production greatly elevated the activity of LOX.

PI3K/AKT Signal Pathway: A Target of Natural Products in the Prevention and Treatment of Alzheimer's Disease and Parkinson's Disease.

Alzheimer's disease (AD) and Parkinson's disease (PD) are two typical neurodegenerative diseases that increased with aging. With the emergence of aging population, the health problem and economic burden caused by the two diseases also increase. Phosphatidylinositol 3-kinases/protein kinase B (PI3K/AKT) signaling pathway regulates signal transduction and biological processes such as cell proliferation, apoptosis and metabolism. According to reports, it regulates neurotoxicity and mediates the survival of neurons through different substrates such as forkhead box protein Os (FoxOs), glycogen synthase kinase-3ß (GSK-3ß), and caspase-9. Accumulating evidences indicate that some natural products can play a neuroprotective role by activating PI3K/AKT pathway, providing an effective resource for the discovery of potential therapeutic drugs. This article reviews the relationship between AKT signaling pathway and AD and PD, and discusses the potential natural products based on the PI3K/AKT signaling pathway to treat two diseases in recent years, hoping to provide guidance and reference for this field. Further development of Chinese herbal medicine is needed to treat these two diseases.