Conjugated Linoleic Acid Induces Apoptosis by Activating AMPK in MCF-7 Breast Cancer Cells

Rhei Rhizoma (RR; 大黃) consists of the underground parts (rhizome and root) of Rheum officinale Baill. and Rheum palmatum L. (Polygonaceae), and is widely used in Southeast Asian folk medicine to alleviate liver and kidney damages. In this study, we investigated into the efficacy and mechanism of RR water extract in supporting neuronal survival in a hypoxia model of cultured rat hippocampal neurons. RR exhibited no cytotoxicity up to 10 μg/ml and exhibited neurosupportive effects at 2.5 μg /ml in normoxia. When RR was added to the culture media on 10 days in vitro (DIV10) and given a hypoxic shock (2% O2/5% CO2, 3 hr, 37 o C) on DIV13, RR exhibited neuroprotective effects on 5 days post-shock. H2DCF stainings indicated that RR effectively prevents ROS production in both normoxia and hypoxia. JC-1 stainings showed that RR prevents dissipation of MMP in hypoxia. These results indicate that RR protects neurons by suppressing ROS production and MMP loss.

Water Extract of Rhei Rhizoma Prevent Production of Reactive Oxygen Species and Loss of Mitochondrial Membrane Potential in a Hypoxia Model of Cultured Neurons

Lee¹,

Moon

2008

Roles of TLR-4 and NF-κB in Interleukin-6 Expression Induced by Heat Shock Protein 90 in Vascular Smooth Muscle Cells

Rhim¹,

Kim²,

Kim

2008

This study has investigated whether extracellular HSP90 predisposes vascular smooth muscle cells (VSMCs) to pro-inflammatory phenotype. Exposure of rat aortic smooth muscle cells to HSP90 not only enhanced IL-6 release but also profoundly induced IL-6 transcript via promoter activation. HSP90-induced IL-6 promoter activation was suppressed by dominant-negative forms of Toll-like receptor (TLR)-4 and myeloid differentiation factor 88 (MyD88), but not by dominant-negative-forms of TLR-3 and TIR-domain-containing adapter-inducing interferon-β (TRIF). Curcumin, which inhibits dimerization of TLR-4, also attenuated the IL-6 induction by HSP90. Mutation at the NF-κB-or C/EBP-binding site in the IL-6 promoter region suppressed the promoter activation in response to HSP90. The gene delivery of IκB using recombinant adenoviruses and treatment with resveratrol, which inhibit NF-κB activity, attenuated the HSP90-induced IL-6 release from VSMCs. The present study proposes that extracellular HSP90 would contribute to inflammatory reaction in the stressed vasculature by inducing IL-6 in VSMCs, and that TLR-4 and NF-κB would play active roles in the process.

Bioactivity and Chemical Composition of the Essential oil of Tea Tree (Melaleuca alternifolia)

Yang¹,

Jeon²,

Lee³

et al. 2008

The essential oil of tea tree (Melaleuca alternifolia) is widely used in traditional Australian medicine for skin lesions and infected injuries. In the present study, we investigated the chemical composition, cytotoxicity and its biological activities. The composition of the oil was analyzed by GC-MS. β-Terpinene (20.87%), α-pinene (17.60%), p-cymene (11.23%), 3-carene (10.40%), trans-anethole (8.47%) and limonene (4.65%) were the major components in the oil. The results tested by MTT assay indicated that the oil showed no cytotoxic effect, at concentrations up to 5%, for less than 3h. The antiradical capacity was evaluated by measuring the scavenging activity of the essential oil on the 2,20-diphenylpicrylhydrazyl (DPPH) and 2,2'-azino-bis 3-ethyl benzothiazoline-6-sulfonic acid (ABTS) radicals. The oil was able to reduce the both radicals dose-dependently, and the concentration required for 50% reduction (RC50) against ABTS radicals (1.6±0.02%) was slightly lower than DPPH radicals (2.6±0.29%). The direct contact and vapor-phase antibacterial activity of the oil were also evaluated using disc diffusion method against Staphylococcus aureus, Streptococcus mutans, Listeria monocytogenes, Acinetobacter baumannii, Escherichia coli, and Vibrio parahaemolyticus. All the Gram-negative bacterial strains tested showed more sensibility to the oil than the Gram-positive strains when compare to the effect of gentamycin. On the other hand, the vapor phase of the essential oil against S. aureus exhibited strongest inhibitory effect.