Citrus hystrix Extracts Protect Human Neuronal Cells against High Glucose-Induced Senescence

Abstract

Citrus hystrix (CH) is a beneficial plant utilized in traditional folk medicine to relieve various health ailments. The antisenescent mechanisms of CH extracts were investigated using human neuroblastoma cells (SH-SY5Y). Phytochemical contents and antioxidant activities of CH extracts were analyzed using a gas chromatograph–mass spectrometer (GC-MS), 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay and 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) assay. Effects of CH extracts on high glucose-induced cytotoxicity, reactive oxygen species (ROS) generation, cell cycle arrest and cell cycle-associated proteins were assessed using a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium (MTT) assay, non-fluorescent 2′, 7′-dichloro-dihydrofluorescein diacetate (H2DCFDA) assay, flow cytometer and Western blot. The extracts protected neuronal senescence by inhibiting ROS generation. CH extracts induced cell cycle progression by releasing senescent cells from the G1 phase arrest. As the Western blot confirmed, the mechanism involved in cell cycle progression was associated with the downregulation of cyclin D1, phospho-cell division cycle 2 (pcdc2) and phospho-Retinoblastoma (pRb) proteins. Furthermore, the Western blot showed that extracts increased Surtuin 1 (SIRT1) expression by increasing the phosphorylation of Glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Collectively, CH extracts could protect high glucose-induced human neuronal senescence by inducing cell cycle progression and up-regulation of SIRT1, thus leading to the improvement of the neuronal cell functions.

Momordica charantia L. Extract Protects Hippocampal Neuronal Cells against PAHs-Induced Neurotoxicity: Possible Active Constituents Include Stigmasterol and Vitamin E

“…GC-MS/MS analysis of MC extract was performed with the facility available at the Scientific and Technological Research Equipment Center (STREC), Chulalongkorn University, Thailand, according to the standard procedure [ 16 ]. The mass spectra obtained were correlated with the database from NIST2011 Mass Spectrometry Data Center for the identification of phytoconstituents.…”

“…Cells (5 × 10 3 cells) were treated or co-treated with MC and phenanthrene (Phe) for 48 h. ROS levels were measured, according to the protocol described elsewhere [ 16 ], and the fluorescence was measured using an EnSpire Plate Reader (Perkin-Elmer) with excitation/emission wavelengths of 485/535 nm.…”

“…Cells (1 × 10 5 cells) were co-treated with Phe and MC for 48 h. After treatment, apoptosis was analyzed in each experimental group using flow cytometry (FACSCalibur), according to the standard protocol [ 16 ].…”

“…Treatment to the cells (2.5 × 10 5 cells) was done, as explained earlier, and proteins from each experimental group were obtained by lysis using NP-40 lysis buffer. Western blotting was performed using the standard experimental procedure [ 16 ] with primary antibodies (cyclin D1 (1:2000), phospho-p38 (1:2000), p38 (1:2000), p53 (1:2000), and GAPDH (1:5000)) and anti-rabbit IgG. HRP-linked secondary antibody bands were developed using chemiluminescence detection reagent and the obtained bands were processed using ImageJ software.…”

Hibiscus sabdariffa extract protects HT-22 cells from glutamate-induced neurodegeneration by upregulating glutamate transporters and exerts lifespan extension in C. elegans via DAF-16 mediated pathway

“…Plants have often been used to improve cognitive functions and retain the mental ability for centuries. Recent studies from our lab have reported the neuroprotective efficacies of various plant extracts, including Kaempferia parviflora, Cleistocalyx nervosum, Bacopa monnieri, and Citrus hystrix against toxic insults in cellular and nematode models [10][11][12][13][14].…”