Curcumin is an inhibitor of tyrosinase with IC50 value of 47uM [1].
Curcumin is a natural compound with potency of anticancer. It is currently under clinical investigation for cancer chemoprevention. There is a variety of biochemical mechanisms of this anticancer function. The targets of Curcumin are involved in signaling pathways include transcription factors, growth factors,
inflammatory cytokines, receptors, and enzymes. Phase I trials have tested the toxicity and tolerability of Curcumin and found that Curcumin has no toxicities at doses up to 12 g/day. However, the bioavailability of Curcumin is quite poor. It is about ~1% after oral administration in phase I/II clinical trials and this hinders Curcumin‘s use in the clinic [2].
It is also reported that Curcumin reduces the generation of amloid beta (Aβ 40 and Aβ42) in SH-SY5Y neuroblastoma cells. It also down-regulates the expression of PS1 and GSK-3β in cells. All these cause the inhibition of Aβ formation and make Curcumin to be a potent therapeutic agent in AD [3].
参考文献:
[1] Sachiko Shirota, Kouji Miyazaki, Ritsuo Aiyama, Minoru Ichioka and Teruo Yokokura. Tyrosinase inhibitors from crude drugs. Biol. Pharm. Bull. 1994, 17 (2): 266-269.
[2] Wungki Park, A.R.M Ruhul Amin, Zhuo Georgia Chen, and Dong M. Shin. New perspectives of curcumin in cancer prevention. Cancer Prev Res (Phila). 2013, 6(5): 387–400.
[3] Zhang Xiong, Zhang Hongmei, SiLu, LiYu. Curcumin mediates presenilin-1 activity to reduce β-amyloid production in a model of Alzheimer’s disease. Pharmacological Reports. 2013, 63: 1101-1108.
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Cell experiment: |
T47D breast cancer cell line is grown in RPMI 1640 supplemented with 10% FBS, 2 mg/mL sodium bicarbonate, 0.05 mg/mL penicillin G, 0.08 mg/mL streptomycin. Culture is maintained on plastic flask and incubated at 37°C in 5% CO2. After growing sufficient amount of cells, cytotoxic effect of silibinin and curcumin is studied by 24, 48 and 72 h MTT assays in which 1000 cell/well are cultivated in a 96 well plate. After 24 h incubation in 37°C with humidified atmosphere containing 5% CO2, the cells are treated with serial concentrations of curcumin (5, 10, 20, 30, 40, 50, 60, 80, 100 μM), silibinin (20, 40, 60, 80, 100, 120, 140, 180, 200 μM), and curcumin-silibinin mixture (each of them 5, 10, 20, 30, 40, 50, 60, 80, 100 μM) for 24, 48 and 72 h in the quadruplicate manner, in addition to cells with 200 μL culture medium containing 10% DMSO for control. After incubation, the medium of all wells of the plate are exchanged with fresh medium and the cells are leaved for 24 h in incubator. Then, medium of all wells are removed carefully and 50 μL of 2 mg/mL MTT dissolved in PBS is added to each wells and the plate is covered with aluminum foil and incubated for 4.5 h again. After removing content of the wells, 200 μL pure DMSO is added to the wells. Then, 25 μL Sorensen’s glycine buffer is added and immediately absorbance of each wells is read in 570 nm using EL×800 Microplate Absorbance Reader with reference wavelength of 630 nm. |
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Animal experiment: |
Curcumin (10?mg/kg), freshly suspended in saline, is administrated by oral gavage once a day for 3?weeks. Forty rats are randomLy assigned to 4 groups (n=10/each group): group I receives saline and serves as control, group II receives curcumin, group III is exposed to CMS andreceive saline and group IV are subjected to CMS andreceive curcumin. |
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参考文献: [1]. Gao S, et al. Curcumin attenuates arsenic-induced hepatic injuries and oxidative stress in experimental mice through activation of Nrf2 pathway, promotion of arsenic methylation and urinary excretion. Food Chem Toxicol. 2013 Jul 18. pii: S0278-6915(13)004 |
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