Phytochemical and biological studies of the extracts of Pseuduvaria Monticola and Pseuduvaria Macrophylla / Hairin Taha

Hairin, Taha (2016) Phytochemical and biological studies of the extracts of Pseuduvaria Monticola and Pseuduvaria Macrophylla / Hairin Taha. PhD thesis, University of Malaya.

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Abstract

The chemical constituents of two Pseuduvaria species from the Annonaceae family; Pseuduvaria monticola and Pseuduvaria macrophylla have been investigated. The extraction of the compounds from the bark and leaves was carried out using n-hexane, dichloromethane and methanol followed by chromatographic techniques such as column chromatography (CC), preparative thin layer chromatography (PTLC) and high performance liquid chromatography (HPLC). Structural elucidations of the compounds were established through spectroscopic methods; 1D-NMR (1H,13C, DEPT 135 ), 2D-NMR (COSY, HMQC, HMBC), UV, IR and MS (LC-MS, GC-MS) and comparison from the published data. The leaf essential oils were extracted by Clavenger-type apparatus and analyzed by GC-MSTOF. A total of 29 chemical constituents ( 3, 39, 40, 4, 41, 42, 43, 14, 15, 32, 44, 45, 46, 47, 48, 39, 10, 5, 7, 16, 49, 26, 50, 52, 53, 54, 55) including 2 new compounds (32, 51) were isolated and elucidated from both species. 15 chemical compounds were isolated from the bark and leaves of Pseuduvaria monticola. They are four oxoaporphine alkaloids; liriodenine (3), lysicamine (39), oxoputerine (40), ouregidione (4), two phenanthrene alkaloids; atherosperminine (41) and argentinine (42), one sesquiterpene; tau cadinol (43), three benzopyran derivatives; oligandrol (14), (6E,10E) isopolycerasoidol (15), (6E,10E) isopolycerasoidol methyl ester (a new compound) (32), two phenolic acids; caffeic acid (44) and chlorogenic acid (45), two fatty acids; n-hexadecanoic acid (46), methyl oleate (47) and one sterol; stigmasterol (48). From Pseuduvaria macrophylla, 14 compounds were isolated from the leaves and bark. They are one new compound; 1,3,5,7-tetramethoxy-2-naphthoic acid (51), five oxoaporphine alkaloids; liriodinine (3), lysicamine (39) atherospermidine (10), N-methyl ouregidione (5) and O-methylmoschatoline (7), two benzopyran derivatives; polycerasoidol (16) and polycerasoidin (49), two phenyl propanoids; elimicin (26) and elimicin 6-methoxy (50), two sterols; β-sitosterol (52) and stigmasta-5,22-diene, 3 methoxy (53) and two fatty acids; oleic acid (54) and n-hexadecanoic acid methyl ester (55). The major compounds in the leaf essential oils of Pseuduvaria monticola were alpha cadinol (56) (13.0 %), cis-calamenene (57) (6.9 %) and alpha copaene (25) (4 %) whereas the major compounds in the leaf essential oils of Pseuduvaria macrophylla were caryophyllene oxide (29) (29.7 %) and elimicin (26) (28 %). In DPPH assay, polycerasoidol (16) and (6E,10E) isopolycerasoidol (15) demonstrated good antioxidant activity (IC50 of 18.89 μg/mL and 22.56 μg/mL) respectively, compared to quercetin (IC50 7.01 μg/mL ). Leaf essential oil of Pseuduvaria macrophylla exhibited slightly greater antioxidant activity than that of Pseuduvaria monticola. In anticancer activity, (6E, 10E) isopolycerasoidol (15) and (6E,10E) isopolycerasoidol methyl ester (32) demonstrated cytotoxic effects on MCF-7 and MDA-MB-231 human breast cancer cells (IC50 59 ± 5.1, 43 ± 2.4 and 76 ± 8.5, 58 ± 2.6 respectively) and induced apoptosis. In antidiabetic study, the bark methanolic extract of Pseuduvaria monticola induced the glucose uptake and insulin secretion of mouse pancreatic β-cell line (NIT-1) and upregulated insulin secretion and downregulated oxidative stress and hyperglycemia in STZ-nicotinamide-induced type 2 diabetic rats whereas the methanol extract of Pseuduvaria macrophylla upregulated insulin and C-peptide levels and down-regulated hyperglycemia and oxidative stress in STZ-nicotinamide-induced type 2 diabetic rats.

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