الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Phenolic compounds from natural sources are receiving increasing attention recent years since they were reported to have a remarkable spectrum of biological activities including antioxidant, anti-inflammatory and anti-carcinogenic activities. They may have many health benefits and can be considered possible chemopreventive agents against cancer.
In this research, we attempted to isolate and characterize phenolic compounds from Pluchea dioscoridis. Solvent extraction and a series of column chromatography methods were used for isolation of compounds, while structures were elucidated by integration of data from chemical reaction, comparative paper chromatography, UV, MS, 1HNMR and 13CNMR. Antimicrobial, Hepatoprotective and anticancer activities of 70% ethanolic extract were evaluated.
The aerial parts of Pluchea dioscoridis were air dried, grounded and the phenolic compounds were extracted with 70% aqueous ethanol several times. The aqueous ethanolic extract was applied on polyamide 6S column and eluted with water and water/ethanol mixtures with gradual increase in concentration. The successive extraction of plant afforded the isolation of nine phenolic compounds, which are Kaempferol 3-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside (A1), Quercetin 3-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside (Rutin) (A2), 5, 7, 4ʼ-trihydroxy 8-C-glucopyranoside (vitexin) (A3), 5, 7, 4ʼ-trihydroxy 6-C-glucopyranoside (isovitexin) (A4) Quercetin-3-O-α-L- rhamnopyranoside (A5), Kaempferol 3-O-β-D-glucopyranosyl (A6), Quercetin 3-O-β-D-glucopyranosyl (A7), Kaempferol (A8) and Quercetin (A9).
Pharmacological studies demonstrated that, In the anti-proliferative bioassay, the 70% aqueous ethanolic extract of Pluchea dioscoridis showed significant growth inhibitory activities against HepG2, HeLa, HCT, MCF-7 and HEp2 tumor cells with IC50 values in the range of 10-23 µg/ml. The extract was proved to have no cytotoxic effect on the normal cells (vero cell line). The hepatoprotective activity of ethanolic extract of pluchea dioscoridis has been evaluated, administration of the aqueous ethanolic extract of Pluchea dioscoridis before CCl4 injection displayed significant decrease in the levels of ALT and showed marked decrease in AST, γ-GT and ALP levels. The histopathological study also demonstrates that the ethanolic extract of Pluchea dioscoridis had hepatoprotective effect.
Also, the 70% aqueous ethanolic extract of Pluchea dioscoridis was tested for the antimicrobial tests against some pathogenic Gram positive (Staphylococcus aureus, Bacillis subtilis and Streptococcus pyogenes) and Gram negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Salmonella typhimurium, Proteous vulgaris and Klebsiella pneumoniae) as well as some unicellular and filamentous fungi (Aspergillus flavus, Candida albicans, Penicillium italicum, Syncephalastrum racemosum, Aspergillus fumigatus, Aspergillus niger and Geotrichum candidum). The ethanolic extract of Pluchea dioscoridis exhibited a potent antifungal and antibacterial activities against all tested fungi and bacteria except Syncephalastrum racemosum, Pseudomonas aeruginosa and Proteous vulgaris. Finally, MIC determination was carried out to calculate the lowest concentration of the antimicrobial agent for inhibition of different microbes. The ethanolic extract was found to be more effective against Streptococcus pyogenes with the lowest MIC value (0.97µg/ml).