Bioactive compound from the Tibetan turnip (Brassica rapa L.) elicited anti-hypoxia effects in OGD/R-injured HT22 cells by activating the PI3K/AKT pathway

Antioxidant Capacity and Protective Effects on H2O2-Induced Oxidative Damage in PC12 Cells of the Active Fraction of Brassica rapa L

Brassica rapa L. (BR), a traditional biennial herb belonging to the Brassica species of Brassicaceae, has been widely used for functions of anti-inflammatory, antitumor, antioxidation, antiaging, and regulation of immunity. In this study, antioxidant activity and protective effects on H2O2-induced oxidative damage in PC12 cells of the active fractions of BR were investigated in vitro. Among all active fractions, the ethyl acetate fraction of ethanol extract from BR (BREE-Ea) showed the strongest antioxidant activity. Additionally, it was noted that BREE-Ea and n-butyl alcohol fraction of ethanol extract from BR (BREE-Ba) both have protective effects in oxidatively damaged PC12 cells, while BREE-Ea displayed the best protective effect in all determined experimental doses. Furthermore, flow cytometry (DCFH-DA staining) analysis indicated that BREE-Ea could reduce the H2O2-induced apoptosis in PC12 cells by reducing the production of intracellular reactive oxygen species (ROS) and increasing enzymatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Moreover, BREE-Ea could decrease the malondialdehyde (MDA) content and reduce the release of extracellular lactic dehydrogenase (LDH) from H2O2-induced PC12 cells. All these results demonstrate that BREE-Ea has a good antioxidant capacity and protective effect on PC12 cells against apoptosis induced by H2O2 and that it can be used as a good edible antioxidant to improve the body's endogenous antioxidant defense.

The protection impact of tectoridin on PC12 cell preventing OGD/R-caused damage through PI3K/AKT signaling channel

The present work examined the effect exerted by tectoridin preventing oxygen glucose deprivation/reoxygenation (OGD/R) damage within PC12 cell. We incubated PC12 cells with Na₂S₂O₄ (10 mM) for 2 h, and tectoridin at different concentrations was then added; based on methyl-thiazolyl-tetrazolium (MTT) and lactate dehydrogenase (LDH) tests, the protection impact was tested. 2',7'-dicholorofluorescein diacetate (DCFH-DA), Fluo-3AM, and 5, 5', 6, 6' -tetrachloro-1, 1', 3, 3' -tetraethyl-imidacarbocyanine iodide (JC-1) staining, and Western blotting were used for determining reactive oxygen species (ROS) level, intracellular Ca²⁺ content, mitochondrial membrane potential (MMP) and the related proteins contents. As a result, tectoridin could improve the cell viability and inhibit the release of LDH. In-depth studies demonstrated that tectoridin limited the overproduction of ROS and intracellular Ca²⁺ content and increased MMP, which showed a close association with ROS-mediated mitochondrial function. Moreover, tectoridin hindered apoptosis based on the up-regulation of the expressions of p-AKT, Bcl-2/Bax and p-mTOR. Furthermore, the level of Nrf2 was also improved by treatment of tectoridin. In addition, the expression of Bcl-2/Bax, p-Akt, p-mTOR, Nrf2, HO-1, NQO1 and GCLM were reduced by LY294002 and the protective role of tectoridin was limited by LY294002. The results unambiguously suggested that tectoridin reduced OGD/R-caused damage to PC12 cells and might ensure neuroprotection by stimulating the PI3K/AKT signaling channel.

Brassica rapa L. (Tibetan turnip) prevents sleep-deprivation induced cognitive deficits via the inhibition of neuroinflammation and mitochondrial depolarization

Brassica rapa L., an edible, feeding and medicinal plant cultivated on the Tibetan plateau with altitudes above 3800 m, has several pharmacological effects. However, its therapeutic effects against memory impairment and central fatigue have yet to be conclusively established. In this study, the Y-maze and Morris water maze tasks revealed that Brassica rapa L. aqueous extract (BE) significantly ameliorated cognitive deficits of sleep deprivation (SD)-treated mice. Moreover, BE treatment partially alleviated SD-induced reductions in the levels of peripheral energy metabolism, and significantly decreased inflammatory factor levels in serum and hippocampus. In addition, BE treatment significantly relieved central fatigue and stabilized the excitability as well as activities of neurons by regulating the levels of hypothalamus tryptophan metabolites and striatum neurotransmitters. The neuroprotective effects of BE were also confirmed using glutamate-treated HT22 cells, whereby BE pretreatment significantly attenuated intracellular ROS production and mitochondrial depolarization via adenosine 5'-monophosphate activated protein kinase/peroxisome proliferators-activated receptors (AMPK/PPAR-γ) signaling pathways. Thus, BE might probably prevent SD-induced learning and memory deficits by inhibiting neuroinflammation and restoring mitochondrial energy metabolism in the hippocampus. These findings imply that BE is a potential complementary therapy for those suffering from deficient sleep or neurometabolic disorders, although this needs verification by prospective clinical studies.