Mechanism of platycodin D-induced apoptosis in A549 human lung cancer cells / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the molecular mechanism of platycodin D showing the inhibitory effect on proliferation and induced apoptosis of humane long cancer cells A549.</p><p><b>METHOD</b>Humane long cancer cells A549 were cultured in vitro, with the final PD concentration of 5-20 micromol x L(-1). PD's inhibitory effect on cell proliferation was examined by MTT assay. Morphological changes in cells were observed with microscope. The cell apoptosis rate was detected by Annexin V-FITC/PI double staining. The change of mitochondrial membrane potential was detected by JC-1. The protein expressing of leaved Caspase-3, cleaved Caspase-9, cleaved PARP, Bcl-2, Bcl-xl, Bak and Bax were detected by Western blot analysis.</p><p><b>RESULT</b>PD could inhibit the proliferation of A549 cells and show stronger effect with the increase of concentration and over time. Compared with the control group, PDs of different concentration showed significant increase in the cell apoptosis rate, decrease in mitochondrial membrane potential after 24 h. Protein electrophoresis inspection showed cut segments in both protein Caspase-3 and Caspase-9 and notable fractures with time. Further study found that PD decreased Bcl-2, Bcl-xl proteins and increased Bax, Bak proteins after processing A549 cells.</p><p><b>CONCLUSION</b>PD shows notable effect on cytotoxicity and can induce A549 cell apoptosis. It causes decrease in mitochondrial membrane potential by regulating Bax, Bak, Bcl-2 and Bcl-xl expressions, and thus activating caspase and finally causing long cancer cell apoptosis.</p>

Mechanisms of (2-methyl-n-butyl) shikonin induced apoptosis of gastric cancer SGC-7901 cells / 药学学报

This study is to investigate the effect of (2-methyl-n-butyl) shikonin (MBS) on inducing apoptosis of human gastric cancer cell line SGC-7901 and the role of ERK1/2 signal pathway in the apoptosis. MTT assay was used to detect SGC-7901 cell proliferation. DNA condensation was measured by DAPI stain. Cell apoptosis was analyzed by flow cytometry. Mitochondrial membrane potential (MMP) was analyzed by JC-1 staining. The protein expressions of Bcl-2, Bax, Survivin, cleaved caspase-9, cleaved caspase-3, cleaved PARP, p-ERK1/2, ERK1/2, p-JNK, JNK, p-p38 and p38 were detected by Western blotting. The results showed that MBS reduced the cell viability of SGC-7901 cells in a dose- and time-dependent manner. The IC50 at 24 h and 48 h for SGC-7901 cells was 10.113 and 4.196 micromolL(-1), respectively. After being treated with MBS, the typical nuclear condensation was observed in SGC-7901 cells by DAPI stain. Apoptosis in SGC-7901 cells was induced by MBS in a dose dependent manner. The protein expression of Bcl-2 was down-regulated, while the protein expressions of cleaved caspase-9, cleaved caspase-3, cleaved PARP, p-ERK1/2 and p-JNK were up-regulated after MBS treatment. U0126, a specific MAP kinase (MEK1/2) inhibitor, blocked the ERK1/2 activation by MBS. MMP was decreased by MBS treatment. It can be concluded that MBS could inhibit SGC-7901 cell proliferation and induce apoptosis. Mitochondrial apoptosis pathway, ERK1/2 signal pathway and JNK signal pathway might be involved in this process.

Biological effects and toxicology studies of melamine and its derivative cyanuric acid / 浙江大学学报·医学版

Melamine (Tripolycyanamide) and its derivatives have recently become a public concern on food safety. To better understand melamine and its major derivative cyanuric acid.literature on their chemical properties, metabolism, biological effects, relevant toxicology studies, and the detection methods is reviewed. Studies indicate that the acute toxicity of melamine and cyanuric acid is low. In mammalian, these compounds are hardly metabolized in vivo and are rapidly eliminated in the urine. When used in large dosage,these compounds demonstrate marked renal toxicity,as well as toxic effect towards heart. The renal toxicity is exemplified by the calculi formation, acute renal failure, and subsequently induced carcinomas of the urinary bladder. Among the tested species, male cats and rats are more prone to be affected by the compounds. The HPLC/MS/MS is becoming the mainstay of the detection methods. Despite of the achieved knowledge on melamine and cyanuric acid, further research is warranted to unveil the mechanism of underlying susceptibility of kidney, to develop better analytic methods,and to explore possible biomarkers for better clinical diagnosis.

Relationship between antibacterial activity of aloe and its anthaquinone compounds / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the relationship between the antibacterial activity of aloe and its contents of anthaquinone compounds, measure and compale antibacterial activities of aloin and aloe-emodin, and analyse the effect of glycoside on the antibacterial activity of aloin.</p><p><b>METHOD</b>The antibacterial activities of the extracts from the outer leaf of Aloe saponaria Haw, aloin and aloe-emodin against three Gram-negative and two Gram-positive bacteria were investigated with the method of agar diffusion. The antibacterial effect of aloin on E. coli was further studied with scanning electron microscopy.</p><p><b>RESULT</b>The antibacterial activities of aloe showed to be dependent on the dose of anthraquinone, aloin (1 g x L(-1)) exhibited higher antibacterial activity [inhibition diameter > (7. 1 +/- 0.15) mm] than Aloe-emodin (inhibition diameter < 5.0 mm), and aloin changed the morphology of E. coli and damaged the outer cell structrue.</p><p><b>CONCLUSION</b>Anthraquinone compounds are the active antibacterial components in aloe and aloin is the main active compound. The glycoside makes it easy for aloin to invade cells and enhances its activity.</p>