الفهرس 
Introduction
Chapter I: Preliminary phytochemical screening of the powdered bulbs of H. vittatumOnly 14 pages are availabe for public view
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Abstract
Hippeastrum vittatum is a perennial herb belonging to family Amaryllidaceae, showing a flowering tunicated single bulb and attaining a height of 50-70 cm on flowering, which extends from March to July. It is natively distributed throughout South America. Besides its popularity as ornamental plant with beautiful and elegant flowers, H. vittatum possess interesting biological activities. Phytochemical analysis has recently yielded a number of important phytocompounds, particularly alkaloids, with significant biological properties. The current study of H. vittatum bulbs included:
Part I:
Phytochemical study of H.vittatum including:
Phytochemical screening of H. vittatum bulbs.
Extraction, fractionation, isolation, and identification of different constituents from the bulbs of H. vittatum.
Part II:
Biological study of H. vittatum including:
Evaluation of the total phenolic and total flavonoidal contents, and the antioxidant activity.
Evaluation of the antibacterial activity of the total extract, different fractions, and some isolated pure compounds.
Evaluation of the anti-diabetic activity of the mucilage of the bulbs.
The obtained results indicated that the bulbs of H.vittatum contain carbohydrates and/or glycosides, unsaturated sterols and/or triterpenes, flavonoids, and alkaloids, whereas they were free from crystalline sublimates, cardiac glycosides, saponins, tannins, and anthraquinones.
The air-dried powdered bulbs (2.5 kg) were extracted by maceration with 95% ethanol at room temperature. The combined macerate was filtered and the solvent was evaporated to dryness under reduced pressure. The crude extract of bulbs (220 g) was suspended in the least amount of distilled water, transferred to a separating funnel, and then defatted with light petroleum ether. The remaining aqueous solution was acidified with tartaric acid (10%) and extracted with ethyl acetate. The mother liquor was then completely basified with sodium carbonate and re-extracted with ethyl acetate. The fractions were concentrated under reduced pressure to afford the petroleum ether (fraction I, 34.5 g), the non-basic EtOAc (fraction II, 35.0 g), the basic EtOAc (fraction III, 33.5 g), and the aqueous (fraction IV, 110 g). Compound 1 was also precipitated as a creamy powder (80.0 mg) during acid base fractionation. Fraction II was fractionated by VLC using gradient elution with DCM-MeOH to give six subfractions (I1-I6). Subfraction II2 (10.0 g) was further chromatographed on a silica gel column using petroleum ether–EtOAc gradient mixtures to yield five subfractions (II2–F–1: II2–F–5). Compounds 2-16 were obtained after successive purification steps of the resulting subfractions using sephadex LH-20 and HPLC.
Structure elucidation of the isolated compounds was performed with the aid of various spectroscopic techniques, including 1H and 13C NMR, APT, DEPT, HSQC, HMBC, 1H-1H COSY, EI-MS, and ESI-MS analyses, in addition to comparison of their physical, chemical, and chromatographic characters with those of the literature. A list of the isolated compounds is recorded in Table 38.
Evaluation of the total phenolic and total flavonoidal contents and antioxidant activity of the bulbs of H. vittatum
1- Evaluation of the total phenolic content:
The content of total phenolic compounds of the total extract and different fractions of H. vittatum bulbs was determined by the Folin–Ciocalteu method. The highest amount of phenols was observed in the basic ethyl acetate fraction or alkaloid fraction (23.56 ± 0.20 mg gallic acid equivalent/g).
2- Evaluation of the total flavonoidal content:
The total flavonoidal content of the total extract and different fractions of H. vittatum bulbs was compared. The highest content of flavonoids was found in the acidic ethyl acetate fraction (8.62 ± 0.18 mg rutin equivalent/g).