采用程序升温汽化(programmed temperature vaporization,PTV)大体积进样与气相色谱-质谱选择离子扫描模式(GC/MS-SIM)联用,检测了卷烟主流烟气中苯并[a]芘(benzo[a]pyrene B[a]P),优化了PTV-GC/MS-SIM检测卷烟烟气B[a]P的参数。样品经...采用程序升温汽化(programmed temperature vaporization,PTV)大体积进样与气相色谱-质谱选择离子扫描模式(GC/MS-SIM)联用,检测了卷烟主流烟气中苯并[a]芘(benzo[a]pyrene B[a]P),优化了PTV-GC/MS-SIM检测卷烟烟气B[a]P的参数。样品经反相C18固相萃取柱(solid-phase extraction,SPE)纯化后的洗脱液不再需要浓缩,直接应用PTV技术进样,提高了洗脱液的利用率,缩短了分析时间,提高了GC/MS-SIM检测卷烟烟气B[a]P的灵敏度。展开更多
Objective To study the molecular mechanism of the inhibitory effects of vitamin C on benzo[a]pyrene （B[a]P）-induced changes of cell cycle in human embryo lung fibroblast （HELF） cells. Methods The stable transfecta...Objective To study the molecular mechanism of the inhibitory effects of vitamin C on benzo[a]pyrene （B[a]P）-induced changes of cell cycle in human embryo lung fibroblast （HELF） cells. Methods The stable transfectants, HELF transfected with antisense cyclin D1 and antisense CDK4, were established. Cells were cultured and pretreated with vitamin C before stimulation with B[a]P for 24 h. The expression levels of cyclin DI, CDK4, E2FI, and E2F4 were determined by Western blot. Flow cytometric analysis was employed to detect the distributions of cell cycle. Results B[a]P significantly elevated the expression levels of cyclin D 1, E2F1, and E2F4 in HELF cells. Vitamin C decreased the expression levels of cyclin D 1, E2F1, and E2F4 in B [a]P-stimulated HELF cells. Dose-dependent relationships were not found between the different concentrations of vitamin C （10, 100, 500, 1000, and 5000 lamol/L） and the expression levels of cyclin D 1, E2F1, and E2F4 in HELF cells. The expression levels of cyclin D1, E2FI, and E2F4 in B[a]P-treated transfectants were lower than those in B[a]P-treated HELF cells. The expression levels of cyclin DI and E2F4 treated with vitamin C and antisense cyclin D1 were decreased compared with those treated with antisense cyclin DI alone. The effects of vitamin C combined with antisense CDK4 on the expression levels of cyclin DI and E2FI/E2F4 were similar to those of antisense CDK4 alone. B[a]P progressed HELF cells from GI to S phase. Both vitamin C and antisense cyclin DI suppressed the changes of cell cycle progressed by B[a]P. However, antisense CDK4 did not attenuate the above changes. Vitamin C combined with antisense CDK4 markedly suppressed B[a]P-induced changes of cell cycle as compared with antisense CDK4. But the inhibitory effects of vitamin C combined with antisense cyclin DI on B[a]P-induced changes of cell cycle were similar to those of vitamin C alone or antisense cyclin DI alone. Conclusions B[a]P progressed HELF cells from G1 to S phase via intracellular signaling pathway of cyclin D I/E2F. Vitamin C may modulate this signaling pathway to protect cells from injury caused by B[a]P.展开更多
Objective To study the modulatory effect of distillate of Ocimum sanctum （traditionally known as Tulsi） leaf extract （DTLE） on genotoxicants. Methods In the present investigation, we studied the antigenotoxic and ...Objective To study the modulatory effect of distillate of Ocimum sanctum （traditionally known as Tulsi） leaf extract （DTLE） on genotoxicants. Methods In the present investigation, we studied the antigenotoxic and anticlastogenic effect of distillate of Tulsi leaf extract on （i） human polymorphonuclear leukocytes by evaluating the DNA strand break without metabolic activation against mitomycin C （MMC） and hexavalent chromium （Cr^＋6） and （ii） human peripheral lymphocytes （in vitro） with or without metabolic activation against mitomycin C （MMC）, hexavalent chromium （Cr^＋6） and B[a]P by evaluating chromosomal aberration （CA） and micronucleus assay （MN）. Three different doses of DTLE, 50 μL/mL, 100 μL/mL, and 200 μL/mL were selected on the basis of cytotoxicity assay and used for studying DNA strand break, chromosomal aberration and micronucleus emergence. The following positive controls were used for inducing genotoxicity and clastogenicity MMC （0.29 μmol/L） for DNA strand break, chromosomal aberration and 0.51 μmol/L for micronucleus assay; Potassium dichromate （Cr^＋6） 600 μmol/L for DNA strand break and 5 μmol/L for chromosomal aberration and micronucleus assay; Benzo[a]pyrene （30 μmol/L） for chromosomal aberration and 40 μmol/L for micronucleus assay. The active ingredients present in the distillate of Tulsi leaf extract were identified by HPLC and LC-MS. Results Mitomycin C （MMC） and hexavalent chromium （Cr^＋6） induced statistically significant DNA strand break of respectively 69% and 71% （P〈0.001） as revealed by fluorometric analysis of DNA unwinding. Furthermore, the damage could be protected with DTLE （50 μL/mL, 100 μL/mL, and 200 μL/mL） on simultaneous treatment. Chromosomal aberration and micronucleus formation induced by MMC, Cr^＋6 and B[a]P were significantly protected （P〈0.001） by DTLE with and without metabolic activation. Conclusion Distillate of Tulsi leaf extract possesses antioxidants contributed mainly by eugenol, luteolin and apigenin as identified by LC-MS. These active ingredients may have the protective effect against genotoxicants.展开更多
文摘采用程序升温汽化(programmed temperature vaporization,PTV)大体积进样与气相色谱-质谱选择离子扫描模式(GC/MS-SIM)联用,检测了卷烟主流烟气中苯并[a]芘(benzo[a]pyrene B[a]P),优化了PTV-GC/MS-SIM检测卷烟烟气B[a]P的参数。样品经反相C18固相萃取柱(solid-phase extraction,SPE)纯化后的洗脱液不再需要浓缩,直接应用PTV技术进样,提高了洗脱液的利用率,缩短了分析时间,提高了GC/MS-SIM检测卷烟烟气B[a]P的灵敏度。
基金This work was supported by grants of National Natural Science Foundation of China (30371206, 30440420593), 973 National Key Basic Research and Development Program (2002 CB 512905) and Taishan Charitable Association LTD. HK.
文摘Objective To study the molecular mechanism of the inhibitory effects of vitamin C on benzo[a]pyrene （B[a]P）-induced changes of cell cycle in human embryo lung fibroblast （HELF） cells. Methods The stable transfectants, HELF transfected with antisense cyclin D1 and antisense CDK4, were established. Cells were cultured and pretreated with vitamin C before stimulation with B[a]P for 24 h. The expression levels of cyclin DI, CDK4, E2FI, and E2F4 were determined by Western blot. Flow cytometric analysis was employed to detect the distributions of cell cycle. Results B[a]P significantly elevated the expression levels of cyclin D 1, E2F1, and E2F4 in HELF cells. Vitamin C decreased the expression levels of cyclin D 1, E2F1, and E2F4 in B [a]P-stimulated HELF cells. Dose-dependent relationships were not found between the different concentrations of vitamin C （10, 100, 500, 1000, and 5000 lamol/L） and the expression levels of cyclin D 1, E2F1, and E2F4 in HELF cells. The expression levels of cyclin D1, E2FI, and E2F4 in B[a]P-treated transfectants were lower than those in B[a]P-treated HELF cells. The expression levels of cyclin DI and E2F4 treated with vitamin C and antisense cyclin D1 were decreased compared with those treated with antisense cyclin DI alone. The effects of vitamin C combined with antisense CDK4 on the expression levels of cyclin DI and E2FI/E2F4 were similar to those of antisense CDK4 alone. B[a]P progressed HELF cells from GI to S phase. Both vitamin C and antisense cyclin DI suppressed the changes of cell cycle progressed by B[a]P. However, antisense CDK4 did not attenuate the above changes. Vitamin C combined with antisense CDK4 markedly suppressed B[a]P-induced changes of cell cycle as compared with antisense CDK4. But the inhibitory effects of vitamin C combined with antisense cyclin DI on B[a]P-induced changes of cell cycle were similar to those of vitamin C alone or antisense cyclin DI alone. Conclusions B[a]P progressed HELF cells from G1 to S phase via intracellular signaling pathway of cyclin D I/E2F. Vitamin C may modulate this signaling pathway to protect cells from injury caused by B[a]P.
文摘Objective To study the modulatory effect of distillate of Ocimum sanctum （traditionally known as Tulsi） leaf extract （DTLE） on genotoxicants. Methods In the present investigation, we studied the antigenotoxic and anticlastogenic effect of distillate of Tulsi leaf extract on （i） human polymorphonuclear leukocytes by evaluating the DNA strand break without metabolic activation against mitomycin C （MMC） and hexavalent chromium （Cr^＋6） and （ii） human peripheral lymphocytes （in vitro） with or without metabolic activation against mitomycin C （MMC）, hexavalent chromium （Cr^＋6） and B[a]P by evaluating chromosomal aberration （CA） and micronucleus assay （MN）. Three different doses of DTLE, 50 μL/mL, 100 μL/mL, and 200 μL/mL were selected on the basis of cytotoxicity assay and used for studying DNA strand break, chromosomal aberration and micronucleus emergence. The following positive controls were used for inducing genotoxicity and clastogenicity MMC （0.29 μmol/L） for DNA strand break, chromosomal aberration and 0.51 μmol/L for micronucleus assay; Potassium dichromate （Cr^＋6） 600 μmol/L for DNA strand break and 5 μmol/L for chromosomal aberration and micronucleus assay; Benzo[a]pyrene （30 μmol/L） for chromosomal aberration and 40 μmol/L for micronucleus assay. The active ingredients present in the distillate of Tulsi leaf extract were identified by HPLC and LC-MS. Results Mitomycin C （MMC） and hexavalent chromium （Cr^＋6） induced statistically significant DNA strand break of respectively 69% and 71% （P〈0.001） as revealed by fluorometric analysis of DNA unwinding. Furthermore, the damage could be protected with DTLE （50 μL/mL, 100 μL/mL, and 200 μL/mL） on simultaneous treatment. Chromosomal aberration and micronucleus formation induced by MMC, Cr^＋6 and B[a]P were significantly protected （P〈0.001） by DTLE with and without metabolic activation. Conclusion Distillate of Tulsi leaf extract possesses antioxidants contributed mainly by eugenol, luteolin and apigenin as identified by LC-MS. These active ingredients may have the protective effect against genotoxicants.
