الفهرس 
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Abstract
Objectives: The present investigation includes study of some chemical and biological properties of three ornamental plants namely, Bauhinia variegata, Enterolobium cyclocarpum, and Albizia lebbeck.
Methods: leaves methanolic extracts of the three plants were used to detect the presence of terpens, flavonoids,alkaloids, saponins,glycosides and tannins by qualitative methods. Then flavonoids and total polyphenols contents were quantitively estimated for the same methanolic extracts by AlCl3 and Folin Ciocalteu colorimetric methods, respectively . Identification and quantitative analysis of flavonoids and polyphenols for the three plant leaves under study were done by HPLC technique. Different concentrations(50:2000μg/ml)of leaves methanolic extracts were prepared to investigate their inhibitory action on α-amylase by starch iodine method .Similarly the same concentrations were prepared to study their possible antioxidant activity by reducing power method . Another experiment was conducted to evaluate antifungal activity of leaves methanolic extracts by radial growth test on potato dextrose agar media . The used concentrations were400 and 800 ppm of each extract. Antidiabetic ,antihyperipidemic and antioxidant activities of leaves methanolic extracts of Bauhinia variegata and Enterolobium cyclocarpum were studied in streptozotocin treated rats experiment. The diabetic rats daily treated with oral doses (200 or 400 mg/kg) of tested extracts for 22 days. Blood serum was used to estimate the levels of glucose ,total cholesterol,triglycerides,high density cholesterol and low density cholesterol. Liver tissues were used to quantify malondialdehyde and glutathione . Ehrlich ascites carcinoma (EAC)cells grown in suitable suspension culture media were used to evaluate in vitro antitumor activity of methanolic extracts of Bauhinia variegata leaves and stem bark in addition to their resultant fractions .The tested extracts and fractions were prepared in the concentrations of 25,50 and100 μg/ml. Another experiment was conducted to investigate the effect of daily doses (200mg/kg) of ethyl acetate fractions of both Bauhinia variegata leaves and stem bark for 14 days against(EAC)cells in mice. The changes in Body weight , hemoglobin%, red blood cells count, white blood cells count, (EAC)count, tumor volume and mean survival time were recorded. Finally different chromatographic techniques and physiochemical analysis were used to isolate and identify of three pure compound from chloroform fraction of Bauhinia variegata leaves.
Results: Phytochemical screening revealed that alkaloid only detected in Albizia lebbeck ,while other natural components were detected in the three plants . Methanolic extract of Bauhinia variegata leaves contained highest values for total polyphenols and flavonoids. Six flavonoids were identified by HPLC in Bauhinia variegata leaves, rutin had the highest amount. While 7 and 8 flavonoids were detected in Enterolobium cyclocarpum, and Albizia lebbeck, respectively. Also, 14 polyphenolic compounds were detected in Bauhinia variegata leaves,syringic acid was predominant. Lower number of polyphenols were detected in both Enterolobium cyclocarpum, and Albizia lebbeck and their quantities were considerably low. Bauhinia variegata methanolic extract showed higher anti α-amylase and reducing power activities comparing to other two plant extracts. The methanolic extract of Enterolobium cyclocarpum demonstrated a strong antifungal activity against pathogenic fungi. Methanolic extract of Bauhinia variegata leaves had a strong ability to reduce glucose and lipids levels in blood . Levels of malondialdehyde and glutathione in liver tissue revealed that the same extract had in vivo antioxidant capacity . While Enterolobium cyclocarpum had weak antidiabetic,antihyperlipidemic and in vivo antioxidant activities. Methanolic extracts of both Bauhinia variegata leaves and stem bark in addition to their successive extraction fractions demonstrated antitumor activity in vitro against(EAC)cells. Similary ethyl acetate fractions of Bauhinia variegata leaves and stem bark led to decrease EAC count and tumor volume in tumor bearing mice . They also increased mean survival time and improved hematological parameters . Finally three compounds were isolated and identified by different methods of chromatography and physicochemical analysis from chloroform fraction of Bauhinia variegata leaves. They are mixture of β-sitosterol and stegmasterol(1)bis(2-methyl heptyl)phthalate(2)and isomers of phytol ester(3).
Conclusion: Bauhinia variegata extract may be used in controlling diabetes mellitus and considered as antihyperlipidemic agent. It also had antioxidant and antitumor activities due to their high content of polyphenols and flavonoids.