Tamaractam, a New Bioactive Lactam from Tamarix ramosissima, Induces Apoptosis in Rheumatoid Arthritis Fibroblast-Like Synoviocytes.

Chemical investigation of Tamarix ramosissima Ledeb, a traditional herbal medicine used for rheumatoid arthritis (RA) treatment in northwest China, led to the discovery of a new phenolic aromatic rings substituted lactam, tamaractam (1), together with the previously reported compounds cis-N-feruloyl-3-O-methyldopamine (2) and trans-N-feruloyl-3-O-methyldopamine (3). The structures of the compounds were determined by high resolution electrospray ionization mass spectroscopy (HRESIMS) and 1D and 2D-NMR experiments, as well as comparison with the literature data. The effects of the three compounds on the viability of RA fibroblast-like synoviocytes (RA-FLS) were assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Pro-apoptosis effect of compound 1 in RA-FLS was further investigated by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, activated caspase-3/7 level assessment using luminescence assay, and sub-G1 fraction measurement using flow cytometry. It was found that these three compounds displayed variable proliferation inhibitory activity in RA-FLS, and compound 1 exhibited the strongest effect. Compound 1 could remarkably induce cellular apoptosis of RA-FLS, increase activated caspase-3/7 levels, and significantly increase sub-G1 fraction in the cell cycle. The results suggested that compound 1 may inhibit the proliferation of RA-FLS through apoptosis-inducing effect, and these compounds may contribute to the anti-RA effect of T. ramosissima.

Trichodimerol and sorbicillin induced apoptosis of HL-60 cells is mediated by reactive oxygen species.

In this study, two secondary metabolite compounds, trichodimerol and sorbicillin were isolated from the mycelial mass of the marine fungus Trichothecium sp.. It was found that trichodimerol and sorbicillin exhibited strong cytotoxic activity with IC50 values from 6.55 µM to 28.55 µM on three cancer cell lines, HL-60, U937 and T47D. Then HL-60 cells were employed for apoptotic assay. The two compounds could significantly increase the levels of activated caspase-3/7 in a dose-dependent manner and remarkably increase sub-G1 fraction in the cell cycle using flow cytometry, indicating that trichodimerol and sorbicillin potently induced apoptosis in HL-60 cells. Trichodimerol or sorbicillin induced ROS levels also showed dose-dependent increases in HL-60 cells as measured by 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA), while trichodimerol or sorbicillin induced apoptosis was effectively blocked by the ROS inhibitor N-acetyl-L-cysteine (NAC). Western blot results showed that trichodimerol or sorbicillin could increase phosphorylated p38 levels and decrease ERK and phosphorylated ERK levels in a concentration-dependent manner. Our findings suggest that the pro-apoptosis effects of trichodimerol and sorbicillin were mediated by ROS, while activation of p38 and inhibition of ERK may be involved in these effects.

Resveratrol inhibits oligomeric Aß-induced microglial activation via NADPH oxidase.

Microglia­mediated neuroinflammation is key in the pathogenesis of Alzheimer's disease (AD). Several studies have suggested that NADPH oxidase contributes to microglia­mediated neuroinflammation. Resveratrol, which is a natural polyphenolic compound, exerts neuroprotective effects in AD due to its anti­inflammatory properties. The present study aimed to investigate the effects of resveratrol on the activation of oligomeric amyloid ß (oAß)­induced BV­2 microglia, and to determine the role of NADPH oxidase in these effects. Microglial proliferation was measured by high­content screening cell counting and using a bromodeoxyuridine incorporation assay. In addition, the levels of reactive oxygen species (ROS), nitric oxide (NO), tumor necrosis factor (TNF)­α and interleukin (IL)­1ß were assessed. The results of the present study demonstrated that resveratrol inhibited the proliferation of oAß­induced microglia and the production of pro­inflammatory factors, including ROS, NO, TNF­α and IL­1ß. Subsequent mechanistic investigations demonstrated that resveratrol inhibited the oAß­induced mRNA and protein expression levels of p47phox and gp91phox. These results suggested that NADPH oxidase may be a potential target for AD treatment, and resveratrol may be a valuable natural product possessing therapeutic potential against AD.