Studies On Antioxidant Activities And Anticancer Activities Of Amaranthus Viridis L. Extracts

Amaranthus viridis L. is a herbaceous annual belonging to Amaranthaceae and found widely in China. It is generally used as livestock forage grass or unuseful weeds directly. A.viridis L. contains rich nutritions and can be used as a herbal medicine with the effect of clearing heat and detoxicating. Actually, it has been used as a traditional drug in some Asian countries, such as India and Nepal. In recent years, some studies have shown that it has antioxidant activities. But we still have little knowledge of its bioactivities and medicinal value, so we think that it is a very significative work to develop the medicine health care function of A.viridis L. The researches on A.viridis L.’s antioxidant activities, anticancer activities and other bioactivities were did in this paper to provide the scientific basis for its further development and utilization.1. The researches on the antioxidant activitiesTo research the antioxidant activities of the extracts of A.viridis L., DPPH free radical scavenging activity, lipid peroxidation inhibition ability and total phenolic content were determined. The DPPH free radical scavenging activity of the methanol extracts of A.viridis L is the highest and the IC50value is109.25μg/ml. The lipid peroxidation inhibition ability of the methanol extracts of A.viridis L. is the highest. The linoleic acid inhibition ratio is63.5%at100μg/ml. The total phenolic content of the methanol extracts of A.viridis L. is221.7μg/ml which is the highest among all the extracts, too. So we used methanol as the the extracting solvent of lots of materials and dispersed the extracts by water and extracted the mixture by petroleum ether, diethyl ether, ethyl acetate, n-butanol respectively. Next, we determined the DPPH free radical scavenging activity, lipid peroxidation inhibition ability, hydroxyl radical scavenging activity and superoxide anion scavenging activity of the extracts. The research results showed that ethyl ether extract(DEE) and ethyl acetate extract(EAE) had stronger antioxidant activities than the other three kinds of extracts. The IC50values for DPPH free radical scavenging activity were74.1μg/ml and70.3μg/ml respectively. The linoleic acid peroxidation inhibition ratios were40.1%and39.3%respectively at500μg/ml. The hydroxyl radical scavenging ratios were57.5%and57.1%respectively at1mg/ml. The superoxide anion scavenging ratios were56.3%and60.2%respectively at1mg/ml.2. The researches on the anticancer activitiesThe researches on the anticancer activities of DEE and EAE which had the higher antioxidant activities, were conducted in the paper. The MTT analysis results showed that DEE had the cell apoptosis ability to HT-29cells and HepG2cells in a dose dependent manner, but the cytotoxicity of DEE to HEK-293cells wasn’t obvious. When the concentration of DEE was400μg/ml, the cell survival rates of HT-29cells and HepG2cells fell to39.3%and21.5%respectively. The results of microscopic observation showed that50μg/ml,100μg/ml,200μg/ml or400μg/ml of DEE had the obvious cell apoptosis ability in a dose dependent manner after treating the cells for24h whereas after treating for48h50μg/ml of DEE caused the death of lots of HT-29cells and100μg/ml,200μg/ml or400μg/ml of DEE had more obvious cell apoptosis ability than10μg/ml of paclitaxel. For researching the effect of DEE on the ROS (reactive oxygen species) generation in HT-29cells the ROS was detected by a flow cytometry. The results showed that the mean fluorescence intensity (MFI) in HT-29cells increased gradually as the increasing of the concentration of DEE. When the concentration of DEE increased from50μg/ml to400μg/ml, MFI increased from48.58to87.53, proving that DEE could cause the increasing of ROS’content in the HT-29cells. The expression level of caspase-3was tested by RT-PCR analysis. The results showed that DEE could cause the increasing of the expression level of caspase-3in a dose dependent manner. For researching the effect of DEE on the cell cycle of HT-29cells the experiment was conducted by a flow cytometry. The results showed that DEE could cause the increaseing of the cell number in subG1phase, and the reducing of the cell number in G0/G1phase and S phase for HT-29cells.3. The researches on other bioactivitiesThe antibacterial activity of A.viridis L. extracts against Escherichia coli, Staphylococcus aureus and Salmonella enlerica was tested by the method of drug sensitive slips in this paper. The results showed that petroleum ether extract (PEE). DEE and EAE had antibacterial activity to Escherichia coli and the inhibition ability sequence was DEE>EAE>PEE. DEE and EAE had the antibacterial activity to both Staphylococcus aureus and Salmonella enterica and the inhibition ability sequence was DEE>EAE. The n-butanol extract (BAE) and the water extract (WLE) had no antibacterial activities to all the bacterials.To research the antidiabetic activities of A.viridis L. the α-glucosidase inhibition activity of the extracts was tested in this study. The results showed that all the extracts (PEE, DEE, EAE, BAE and WLE) had some inhibitory effect on the α-glucosidase in a dose dependent manner. For the same concentration, PEE had the strongest inhibitory activity and WLE had the weakest inhibitory activity. The inhibition ratios were65.2%、35.3%、30.1%、13.7%、12.8%respectively at500μg/ml.