Emodin induces apoptosis through caspase 3-dependent pathway in HK-2 cells
ABSTRACT Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a major constituent of rhubarb. Although it has been claimed to have a wild spectrum of therapeutic value, its side effects, especially in human kidney cells have not been well characterized. In the present study, we treated human proximal tubular epithelial cell line HK-2 cells with emodin in vitro and evaluated its toxic effects with cell viability, cell cycle phases and induction of apoptosis/necrosis and activity of caspase 3. The proliferation of HK-2 cells was inhibited by emodin in a dose- and time-dependent manner. Cell cycle analysis revealed that HK-2 cells were locked in G1 phase by emodin as for 12h. Apoptosis was supported by the Annexin V/propidium iodide (PI) assay and the occurrence of a sub-G1 peak. Emodin caused an increase in caspase 3-like activities and a caspase 3 inhibitor, Ac-DEVD-CHO, attenuated the apoptosis. These results suggested that HK-2 cells are sensitive to emodin-induced cytotoxic effects, which are mediated through the induction of apoptosis in caspase 3-dependent pathway.
- SourceAvailable from: Surrinder Lattoo[Show abstract] [Hide abstract]
ABSTRACT: Rheum emodi (Polygonaceae), a multipurpose medicinal herb is a rich repository of pharmacologically active secondary metabolites known as anthraquinones. The present study entails HPLC quantitation and in vitro activity of four major constituents and the extracts of R. emodi. The anthraquinone glycosides were more abundant than their aglycone constituents viz. emodin and chrysophanol. MTT assay was used to assess the in vitro antiproliferative activity of anthraquinones and extracts on four cancer cell lines namely MIAPaCa-2, HCT-116, MCF-7 and T47D. The cytotoxicity was more obvious on MIAPaCa-2. Further, the study of mechanism of action involving cell cycle analysis and determination of mitochondrial membrane potential (MMP) loss was also investigated. The extracts significantly reduced cell viability by inducing apoptosis/necrosis and cell cycle arrest with concurrent loss of MMP (∆ψm) in a concentration dependent manner. The methanolic extract of rhizome (SPL5) with the least IC50 value (25 μg/ml) showed a significant increase in the percentage of apoptotic/necrotic cells (42.3% at 100 μg/ml) compared to that of vehicle treated cells (11.6%). These cellular manifestations corresponded remarkably with a decrease in integrity of the mitochondrial membrane. In conclusion, SPL5 with emodin and chrysophanol as the preponderant constituents exhibited considerable antiproliferative activity possibly by reducing cell viability and stirring up ∆ψm loss.South African Journal of Botany 08/2014; 95:1-8. DOI:10.1016/j.sajb.2014.07.012 · 1.34 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: In recent years, a numerous studies had been conducted in all over the world to explore the traditional medicinal system as a resource of complementary and alternative medicine. The Indian indigenous drugs from the medicinal plants also have great importance, both professional and economical point of view. Rheum webbianum Royle commonly known as Rhubarb, is an important medicinal plant, belonging to the family Polygonaceae. It is commonly used for the management of renal function disorders, hyperlipidemia, cancer and improves the memory in senile patients. R. webbianum, R. speciformae, R. tibetana and R. orcroftianum are the commonly found species in cold arid zones of India. The Rheum species contains a number of anthraquinone derivatives. The free anthraquinones viz. rhein, emodin, aloe-emodin, physcion, and chrysophamol are present in nearly all species. Stilbene glycosides, including rhaponticin and the metabolite rhapontigenin, have been identified in the root. Tannins, sennosides, catechins, gallic acid, and cinnaminic acid have been identified. Keeping in view the utility of this plant in certain herbal products and traditional medicine, conservation and sustainable utilization of this rare species is the urgent need of present hour. This will not only provide raw material but also provide resource generation for economic development for the local population in the cold arid high altitude regions of Ladakh Himalaya.
- [Show abstract] [Hide abstract]
ABSTRACT: Emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) and rhein (4,5-dihydroxyanthraquinone-2-carboxyl acid) are two main active compounds in total rhubarb anthraquinones (TRAs), which showed nephrotoxicity in Sprague Dawley (S.D.) rats in our previous study. However, it is unknown yet whether emodin and rhein have cytotoxic effects on kidney. To address this issue, HK-2 cells, a human proximal tubular epithelial cell line, were treated with different concentrations of emodin or rhein, and cell viability and morphological changes were investigated. The ratio of hypodiploid cells and the activity of caspase 3 protease were also detected. Results showed that addition of emodin but not rhein at concentrations above 40microM for 24h reduced cell viability and induced apoptosis in HK-2 cells. Additionally, emodin at apoptosis-inducing concentrations caused expression of cathepsin B (CB) protein and activation of CB protease. Addition of CB inhibitor, CA-074, significantly attenuated the ratio of hypodiploid and apoptotic cells, partially blocked caspase 3 activation and inhibited reduction of cell viability induced by emodin. These data indicate that emodin possesses cytotoxic effects on HK-2 cells partially through induction of CB protein and activation of CB protease.Toxicology Letters 10/2008; 181(3):196-204. DOI:10.1016/j.toxlet.2008.05.013 · 3.36 Impact Factor