الفهرس 
Taxonomy
Preparation of the crude extractOnly 14 pages are availabe for public view
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Abstract
Morus is a small genus consisting of about ten to fifteen species. It is one of the economically important genera of the family Moraceae due to its edible leaves by silkworms in addition to its edible fruits (Nomura, 1988; Nepal, 2008). This genus contains a diverse variety of phenolic compounds (Nomura, 1988; Nomura and Hano, 1994). The present study reported the phytochemical investigation of the bark of Morus nigra, methylation of the isolated stilbens, evaluation of the antioxidant activities of the naturally isolated compounds and evaluation of the antiproliferative activities of the isolated and methylated compounds towards HepG2 and MCF-7 cancer cell lines. Part I Phytochemical study of the stem bark of Morus nigra L. Chapter 1 Phytochemical investigation of the stem bark of Morus nigra L. The barks of M. nigra were collected, dried and extracted with methanol. The extracts were further fractionated and purified using different chromatographic methods including normal and reversed phase silica gel along with sephadex LH-20 columns to afford two compounds 11, 12 from the hexane fraction, five compounds 5, 6, 7, 13, 14 from the methylene chloride fraction and seven compounds 1, 2, 3, 4, 8, 9, 10 from the ethyl acetate fraction, respectively. Chapter 2 Identification of the isolated compounds from the stem bark Morus nigra L. Three stilbenes, 2`,3,4`,5,5`-pentahydroxy-cis-stilbene (1), resveratrol (2), oxyresveratrol (3), four flavonoids, norartocarpetin (4), kuwanon C (5), morusin (6), cudraflavone A (7), three Diels-Alder adducts, kuwanon G (8), albafuran C (9), mulberrofuran G (10), four terpenoids, 3-O-acetyl-α-amyrin (11), 3-O-acetyl-β-amyrin (12) ursolic acid-3-O-acetate (13), and uvaol (14), were isolated from M. nigra stem bark. The structures were elucidated using spectroscopic techniques (1D and 2D-NMR, UV, IR and MS). 2`,3,4`,5,5`-pentahydroxy-cis-stilbene (1) was isolated for the first time from nature. Compounds 7 and 12 were reported for the first time from genus Morus. Compounds 2, 8, 10, 13 and 14 were reported for the first time from M. nigra. Chapter 3 Identification of the methylation products A new methylated stilbene, 2`,3,4`-trimethoxy-5-hydroxy-trans-stilbene (18) was prepared from oxyresveratrol (3) together with another three known analogues, 2`,3,4`,5,5`-pentamethoxy-cis-stilbene (15), resveratrol trimethyl ether (16) and oxyresveratrol tetramethyl ether (17) from compounds 1, 2 and 3, respectively. The structures were elucidated using spectroscopic techniques (1D and 2D-NMR. Part II Biological study of different extracts, isolated and methylated compounds of the stem bark Morus nigra L. Chapter 1 Screening of the antioxidant activity of the different extracts and isolated compounds of the stem bark of Morus nigra L. Free radical scavenging activity of the methanol, n-hexane, methylene chloride and ethyl acetate extracts and isolated compounds were evaluated by the ABTS+ radical antioxidant assay. Among the investigated fractions, the ethyl acetate and the methylene chloride fractions showed remarkable antioxidant activity. All isolated compounds showed high antioxidant activity except cyclized prenylated flavonoids and terpenoids. Chapter 2 Antiproliferative activity of the isolated and methylated products of the stem bark of Morus nigra L. The results showed that compound 5 showed the highest antiproliferative activity against the investigated cell lines. The new stilbene analogue (18) showed remarkable activity towards MCF-7 cell line. Compound 16 strongly suppressed the growth of HepG2 cells. Most of the other isolated and derivatized compounds showed moderate activities towards HepG2 cells and low to moderate activities towards MCF-7 cells.