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ISOLATION AND STRUCTURAL ELUCIDATION OF BIOACTIVE CONSTITUENTS OF COFFEABREVIPES HIERN AND PSEUDOCERATINAPURPUREA CARTER
Published 2014Subjects: “…Antimycobacterial activity…”
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PHYTOCHEMICAL SCREENING AND ANTIMYCOBACTERIAL POTENTIALS OF Syzygium guineense WILD DC. AND Mimosa pigra LINN
Published 2014-09Subjects: “…Antimycobacterial activity…”
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Page will reload when a filter is selected or excluded.- Antimycobacterial activity 2 results 2
- Acetylcholinesterase inhibition 1 results 1
- Coffea brevipes 1 results 1
- Mimosa pigra 1 results 1
- Pseudoceratinapurpurea 1 results 1
- Syzygium guineense 1 results 1
- The increase in the incidence of Alzheimer disease and infections caused by Mycobacterium tuberculosis are of considerable global health challenge. The inability of existing drugs to cure the Alzheimer disease and the rise in multi-drugs resistant strains of M. tuberculosis has led to continuous search for new anti-alzheimer and antimycobacterial drugs. Terrestrial plants and marine organisms have been major sources of bioactive components for drug development. This study was designed to isolate the chemical constituents, and investigate potential antimycobacterial activity of Coffeabrevipes and antiacetylcholinesterase activity of the marine sponge Pseudoceratinapurpurea based on their ethnomedicinal uses. Dried whole plant of C. brevipes (5.0 kg) was extracted with ethanol. The crude extract was macerated with hexane, chloroform and ethylacetate successively. These fractions were screened against two clinical strains of M. tuberculosis (ZMC 303 and 050) at standard load of 10-2 and 10-4 inoculum concentrations using egg enriched Lowensten Jensen medium following standard method. Isoniazid, dihydrostreptomycin, ethambutol and rifampicin were used as positive controls. Freeze dried P. purpurea (1 kg) was extracted with methanol:tetrachloroethylene (1:1). The obtained extract was successively partitioned with hexane, tetrachloroethylene, chloroform and butanol. The fractions were assayed for acetylcholinesterase inhibition using microplate method with galanthamine as positive control. The bioactive compounds were isolated using chromatographic techniques. Structural elucidations of the isolated compounds were carried out using infrared (IR), ultraviolet, 1D and 2D nuclear magnetic resonance augmented with Mass spectroscopy (MS). The C. brevipes crude extract yielded hexane (7.4 g), chloroform (8.5 g) and ethylacetate (9.3 g) fractions. Similar Minimum Inhibitory Concentration (MIC) against ZMC 303 and 050, were obtained for hexane (5 mg/mL), Chloroform and ethylacetate (>1000 mg/mL) fractions. The MIC of isoniazid, dihydrostreptomycin, and ethambutol were 0.2, 8.0 and 2.0 �g/L respectively. Rifampicin was not active against both strains. Two new flavonoids were isolated from C.brevipes named Coffethone A and B with absorptions due to hydroxyl, carbonyl and aromatic C=C groups at ? max 3435, 1712 and 1400-1600 cm-1 in the IR spectrum. The characteristic NMR signals of flavonoids were seen at ? (ppm) of 12.2(1Hs), 12.1(1Hs), 7.8(1Hd, J=7Hz), 7.6(1Hd, J=7Hz), 7.7(1Hs) and 7.1(1Hs). The MS of coffethone A and B suggested the molecular formular C23H24O5 and C23H26O4 at m/z 380.43 and 366.18 respectively. The P. purpurea extract gave hexane (7.4 g), tetrachloroethylene (79.1 g), chloroform (66.4 g) and butanol (115.4 g) fractions. The Acetylcholinesterase inhibitory activity for butanol (93.7%) and chloroform (91.9%) fractions were obtained. Other fractions showed no activities. Three compounds, Bromospiranol, Iso-anomoian and Aplyzansine were isolated from P.purpurea. Their IR spectra showed similar absorption band for the presence of hydroxyl, amide carbonyl and amine at 3400, 1695 and 3300 cm-1. The MS revealed clusters of peaks for pseudomolecular ion at m/z 973.0/974.9/976.9 725/727/730/732 and 740/742/744/746 indicating the presence of bromine atoms in bromospiranol, Iso-anomoian and Aplyzansine respectively. Coffeabrevipes and Pseudoceratinapurpurea extracts are potential sources of antimycobacterial and anti-alzheimer drugs respectively. The new isolated compounds have increased the library of natural products. 1 results 1
- The prevalence of multi-drug resistant tuberculosis is an increasing health challenge. Attention has therefore been shifted to the use of ethno-medicines in combating this disease. Traditionally, Syzygium guineense (stem-bark) and Mimosa pigra (aerial parts) are used in the treatment of respiratory tract infections with no scientific justification. This study was designed to identify the constituents of Syzygium guineense and Mimosa pigra that may be active against Mycobacterium tuberculosis. The S. guineense (stem-bark) and M. pigra (aerial parts) were obtained from farmlands in Abuja and authenticated at the herbarium of National Institute for Pharmaceutical Research and Development, Abuja. The S. guineense (1.0 kg) was extracted successively with chloroform and methanol. The extracts were separately fractionated with n-hexane followed by acetone. Mimosa pigra (0.5 kg) was extracted with methanol and partitioned with diethylether and n-butanol. The fractions were purified using chromatographic techniques. The extracts, fractions and isolated compounds were subjected to antimycobacterial assay with Mycobacterium tuberculosis (ZMC 050 and 303) strains using the Lowenstein-Jensen and mycobacterium growth indicator tube methods. Streptomycin, isoniazid, rifampicin, and ethambutol were used as standard drugs and dimethylsulphoxide as negative control. The structures of the isolated compounds were elucidated using infrared, ultra-violet/visible, nuclear magnetic resonance and mass spectroscopic techniques. The chloroform extract of S. guineense yielded 4.1 g n-hexane fraction and 5.2 g acetone fraction A while the methanol extract gave 5.2 g acetone fraction B and 98.0 g residue. Crude methanol extract of M. pigra gave 40.1, 4.6 and 12.3 g of diethylether, n-butanol and residue fractions respectively. Two new triterpenoids were isolated from S. guineense namely: 12-hydroxy-27-demethylfriedelan-3-one and betulinic acid methylenediol ester, in addition to the two known triterpenoids: betulinic acid, and friedelan-3-one. One new flavonoid, 8-hydroxy-3-phenyl-4-benzopyrone rhamnoside was isolated from M. pigra. The two plants‘ methanol extracts, n-butanol fraction, acetone fraction A, and isolated compounds: betulinic acid, betulinic acid methylenediol ester and 8-hydroxy-3-phenyl-4- benzopyrone rhamnoside were active against ZMC 050 strain with Minimum Inhibitory Concentrations (MIC) of 5.0, 5.0, 2.0, 0.6, 0.6, 0.15 and 0.5 mg/mL respectively. The ZMC 303 strain also gave similar MIC values as ZMC 050 strain. Spectroscopic analysis of 12-hydroxy-27-demethylfriedelan-3-one provided evidence for δH signals: 0.8-1.2 UNIVERSITY OF IBADAN LIBRARY iv (7CH3), 1.2-1.8 (10CH2), and 2.2-2.4 (5CH), δC signals: 29.9-41.7 (5C), 72.8 (1CHOH) and 213.4 (1C=O) with a molecular ion of 428 corresponding to C29H48O2. The betulinic acid methylenediol ester showed δH and δC signals similar to betulinic acid except for the downfield methylenedioxy carbinol (OCH2O) δC signal at 79.0 and molecular ion of 486 correspond to C31H50O4. Betulinic acid and friedelan-3-one signals are similar to published spectra. The 8-hydroxy-3-phenyl-4-benzopyrone rhamnoside showed δH signals: 0.9 (3Hd, J=5.8 Hz), 3.1-3.8 (overlapping glycone multiplet) and 5.2 (anomeric) typical of a rhamnose moiety, with δH 6.2 (1H), 6.4 (1H), 6.9 (5H) and δC 178.0 (1C=O) of the flavonoid ring. The bioactive compounds obtained from Syzygium guineense and Mimosa pigra exhibited anti-mycobacterial activities. They have potentials for the development of drugs for the management of tuberculosis. The new triterpenoids and flavonoids are addition to the library of compounds. Keywords: Syzygium guineense, Mimosa pigra, Antimycobacterial activity, Triterpenoids Word count: 484 1 results 1
- Triterpenoids 1 results 1
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