Absolute Methanol Research Articles

Synthesis, spectral characterization and biological activities of Organotin(IV) complexes with <i>ortho</i>-vanillin-2-hydrazinopyridine (VHP)

Five new organotin(IV) complexes of ortho-vanillin-2-hydrazinopyridine hydrazone with formula [RnSnCl4–n(VHP)] [R = Me2, n = 2 (2); R = Ph2, n = 2 (3); R= nBu2, n = 2 (4); R = nBu, n = 2 (5) and R = 1, n = 0 (6)] have been synthesized by direct reaction of ortho-vanillin-2-hydrazinopyridine hydrazone [(VHP), (1)], base and organotin(IV) chloride(s) in absolute methanol. The hydrazone ligand [(VHP), (1)] and its organotin(IV) complexes (2-6) have been characterized by UV-Visible, FT-IR and 1H NMR spectral studies. Spectroscopic data suggested that in the complexes (2-4), the ligand (1) acted as a neutral bidentate ligand and is coordinated to the tin(IV) atom via the azomethine nitrogen and pyridyl nitrogen atoms, whereas the ligand (1) acted as a uninegative tridentate ligand and coordinated to the tin(IV) atom through phenolic-O, azomethine-N and pyridyl-N atoms in complexes (5-6). The toxicity of the ligand (1) and its organotin (IV) complexes (2-6) were determined against Artemia salina. Organotin(IV) complexes showed moderate activity against Artemia salina. The ligand (1) and its organotin(IV) complexes (2-6) were also tested against four types of bacteria namely Bacillus cereus, Staphylococcus aureus, Escherichia coli and Enterobacter aerogenes. All organotin(IV) complexes and the free ligand (1) showed better antibacterial activities against bacteria. Among the organotin(IV) complexes (2-6), diphenyltin(IV) complex (3) showed higher activity against the four types of bacteria.

Synthesis, Characterization and In Vitro Antibacterial Studies of Organotin(IV) Complexes with 2-Hydroxyacetophenone-2-methylphenylthiosemicarbazone (H(2)dampt).

Five new organotin(IV) complexes of 2-hydroxyacetophenone-2-methylphenylthiosemicarbazone [H2dampt, (1)] with formula [RSnCln-1(dampt)] (where R = Me, n = 2 (2); R = Bu, n = 2 (3); R = Ph, n = 2 (4); R = Me2, n = 1 (5); R = Ph2, n = 1 (6)) have been synthesized by direct reaction of H2dampt (1) with organotin(IV) chloride(s) in absolute methanol. The ligand (1) and its organotin(IV) complexes (2–6) were characterized by CHN analyses, molar conductivity, UV-Vis, FT-IR, 1H, 13C, and 119Sn NMR spectral studies. H2dampt (1) is newly synthesized and has been structurally characterized by X-ray crystallography. Spectroscopic data suggested that H2dampt (1) is coordinated to the tin(IV) atom through the thiolate-S, azomethine-N, and phenoxide-O atoms; the coordination number of tin is five. The in vitro antibacterial activity has been evaluated against Staphylococcus aureus, Enterobacter aerogenes, Escherichia coli, and Salmonella typhi. The screening results have shown that the organotin(IV) complexes (2–6) have better antibacterial activities and have potential as drugs. Furthermore, it has been shown that diphenyltin(IV) derivative (6) exhibits significantly better activity than the other organotin(IV) derivatives (2–5).

Carbohydrase inhibition and anti-cancerous and free radical scavenging properties along with DNA and protein protection ability of methanolic root extracts ofRumex crispus

The study elucidated carbohydrase inhibition, anti-cancerous, free radical scavenging properties and also investigated the DNA and protein protection abilities of methanolic root extract of Rumex crispus (RERC). For this purpose, pulverized roots of Rumex crispus was extracted in methanol (80% and absolute conc.) for 3 hrs for 60℃ and filtered and evaporated with vacuum rotary evaporator. RERC showed high phenolic content (211 µg/GAE equivalent) and strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging (IC50 = 42.86 (absolute methanol) and 36.91 µg/mL (80% methanolic extract)) and reduced power ability. Furthermore, RERC exhibited significant protective ability in H2O2/Fe3+/ascorbic acid-induced protein or DNA damage and percentage inhibition of the HT-29 cell growth rate following 80% methanolic RERC exposure at 400 µg/mL was observed to be highest (10.2% ± 1.03). Moreover, methanolic RERC inhibited α-glucosidase and amylase effectively and significantly (P < 0.05). Conclusively, RERC could be considered as potent carbohydrase inhibitor, anti-cancerous and anti-oxidant.

Synthesis and crystal structures of Schiff base oxovanadium(V) complexes [VO(Bhm)(OCH3)(CH3OH)] and [VO2(Bpp)

Compound [VO(acac)2] reacts with the Schiff bases N′-(5-bromo-2-hydroxybenzylidene)-2-hydroxy-3-methylbenzohydrazide (H2Bhm) and 4-bromo-2-[(2-piperidin-1-ylethylimino)methyl]phenol (HBpp) in absolute methanol to give the oxovanadium(V) complexes [VO(Bhm)(OCH3)(CH3OH)] (I) and [VO2(Bpp)] (II), respectively. Both complexes were characterized by elemental analysis, IR spectra, and single-crystal X-ray determination. The crystal of I crystallizes in the triclinic space group \(P\bar 1\) with a = 7.625(2), b = 11.240(3), c = 12.156(4) A, α = 77.404(5)°, β = 75.770(4)°, γ = 79.922(5)°, V = 977.4(5) A3, Z = 2. The crystal of II crystallizes in the monoclinic space group P2/c with a = 26.760(3), b = 6.655(1), c = 17.570(2) A, β = 100.335(2)°, V = 3078.2(7) A3, Z = 8. The V atom in I is in an octahedral coordination, and those in II are intervenient between square pyramidal and trigonal bipyramidal coordination.

Synthesis and Crystal Structures of Schiff Base Oxovanadium(V) Complexes [VO(BN)(OCH3)]2 and [VO2(BM)

[VO(acac)2] reacts with the Schiff bases N’-(2-hydroxy-4- diethylaminobenzylidene)-2-nitrobenzohydrazide (H2BN) and N’- (2-hydroxy-4-diethylaminobenzylidene)-2-methoxybenzohydrazi de (HBM), respectively, in absolute methanol to give the oxovanadium(V) complexes [VO(BN)(OCH3)]2 (1) and [VO2(BM)] (2). Both complexes were characterized by elemental analysis, infrared (IR) spectra, and single-crystal x-ray determination. The complex (1) crystallizes in the monoclinic space group P21/c, with a = 10.828(2), b = 18.177(4), c = 10.778(2) Å, β = 106.914(3)°, V = 2029.6(7) Å3, Z = 4. The complex (2) crystallizes in the triclinic space group P-1, with a = 8.459(2), b = 10.068(3), c = 11.776(3) Å, α = 88.727(2), β = 88.904(3), γ = 69.486(3)°, V = 939.0(4) Å3, Z = 2. Complex (1) is a centrosymmetric methoxy-bridged dimeric oxovanadium(V) compound, and complex (2) is a monomeric dioxovanadium(V) compound.

(E)-2′-[(3,5-Di-tert-butyl-2-hydroxybenzylidene)amino]-1,1′-binaphthalen-2-ol methanol monosolvate

The title compound, C35H35NO2·CH4O, was obtained by the reaction of rac-2-amino-2-hy­droxy-1,1-binaphthyl and 3,5-di-tert-butyl-2-hy­droxy­benzaldehyde in absolute methanol. In the Schiff base mol­ecule, the two naphthyl bicycles are twisted by 71.15 (5)°. One hy­droxy group is involved in intra­molecular O—H⋯N hydrogen bond, while the methanol solvent mol­ecule is linked to another hy­droxy group via an inter­molecular O—H⋯O hydrogen bond.

Synthesis of CuO and ZnO Nanoparticles and CuO Doped ZnO Nanophotocatalysts

Nanocrystalline copper oxide (CuO) particles were precipitated by using different sources of copper salts and oxalic acids. The transformation to monoclinic CuO is achieved by heating the copper precipitate at 300°C for 4 h. Dice-like and flower-like structures were obtained from the effects of by-product’s acidity to the morphology of copper oxalate (Cu (C2O4)). The particle sizes of all samples, determined by transmission electron microscopy (TEM), were in the range of 10-30 nm. 0.5% CuO doped ZnO (CuO-ZnO) nanophotocatalysts were successfully prepared by mixing synthesized CuO nanoparticles with synthesized ZnO in absolute methanol. No significant changes in morphology were observed between the undoped and doped ZnO except for a higher surface area obtained for CuO doped ZnO. The doping of CuO on ZnO also resulted in enhanced photocatalytic performance of ZnO in the photodegradation of methyl orange dye.

Antioxidant and Antimicrobial Attributes and Phenolics of Different Solvent Extracts from Leaves, Flowers and Bark of Gold Mohar [Delonix regia (Bojer ex Hook.) Raf.

This paper describes the antioxidant and antimicrobial activities and phenolic components of different solvent (absolute methanol, absolute ethanol, absolute acetone, 80% methanol, 80% ethanol, 80% acetone and deionized water) extracts of leaves, flowers and bark of Gold Mohar [Delonix regia (Bojer ex Hook.) Raf.]. The extract yields from leaves, flowers and bark ranged from 10.19 to 36.24, 12.97 to 48.47 and 4.22 to 8.48 g/100 g dry weight (DW), respectively. Overall, 80% methanol extract produced from the leaves exhibited significantly (P < 0.05) higher antioxidant activity, with high phenolic contents (3.63 g GAE/100 g DW), total flavonoid contents (1.19 g CE/100 g DW), inhibition of peroxidation (85.54%), DPPH scavenging capacity (IC50 value 8.89 μg/mL) and reducing power (1.87). Similarly, this 80% methanol leaves extract also showed superior antimicrobial activity. HPLC analysis of the 80% methanol extracts for individual phenolics revealed the presence of gallic, protocatechuic and salicylic acid in leaves; gallic, protocatechuic, salicylic, trans-cinnamic and chlorogenic acid in flowers, and gallic acid in bark as the main (amount > 1.50 mg/100 g DW) phenolic acids. Besides, small amounts (<1.50 mg/100 g DW) of some other phenolic acids such as sorbic, sinapic, p-coumaric, m-coumaric, ferulic, caffeic, 3-hydroxybenzoic, 4-hydroxycinnamic and 4-hydroxybenzoic acids were also detected. The extracts of the tested parts of Gold Mohar, especially, the leaves, might be valuable for functional food and therapeutic applications.

Antibacterial activities of selected medicinal plants in traditional treatment of human wounds in Ethiopia

Objective To evaluate the activity of selected Ethiopian medicinal plants traditionally used for wound treatment against wound-causing bacteria. Methods Samples of medicinal plants ( Achyranthes aspera, Brucea antidysenterica, Datura stramonium, Croton macrostachyus, Acokanthera schimperi, Phytolacca dodecandra, Millettia ferruginea, and Solanum incanum) were extracted using absolute methanol and water and tested for their antimicrobial activities against clinical isolates and standard strains of wound-causing bacteria using agar well diffusion and micro titer plate methods. Results Most of the plant extracts had antibacterial activities, among which Acokanthera schimperi and Brucea antidysenterica inhibited growth of 100% and 35% of the test organisms, respectively. Methanolic extracts had higher activities compared with their corresponding aqueous extracts. The most susceptible organism to the extracts was Streptococcus pyogens while the most resistant were Escherichia coli and Proteus vulgaris. Conclusions This finding justifies the use of the plants in wound healing and their potential activity against wound-causing bacteria. Their toxicity level and antimicrobial activity with different extraction solvents should further be studied to use them as sources and templates for the synthesis of drugs to control wound and other disease-causing bacteria.

Synthesis and characterization of tin(IV)/organotin(IV) complexes with 2-benzoylpyridine-N(4)-cyclohexylthiosemicarbazone [HBPCT]: X-ray crystal structure of [SnCl3(BPCT)

Four new tin(IV)/organotin(IV) complexes, [SnCl3(BPCT)] (2), [MeSnCl2(BPCT)] (3), [Me2SnCl(BPCT)] (4), and [Ph2SnCl(BPCT)] (5), have been synthesized by the direct reaction of 2-benzoylpyridine-N(4)-cyclohexylthiosemicarbazone [HBPCT, (1)] and stannic chloride/organotin(IV) chloride(s) in absolute methanol under purified nitrogen. HBPCT and its tin(IV)/organotin(IV) complexes (2–5) were characterized by CHN analyses, molar conductivity, UV-Vis, FT-IR, and 1H NMR spectral studies. In all the complexes, tin(IV) was coordinated via pyridine-N, azomethine-N, and thiolato-S from 1. The molecular structure of 2 has been determined by X-ray single-crystal diffraction analysis. Complex 2 is a monomer and the central tin(IV) is six-coordinate in a distorted octahedral geometry. The crystal system of 2 is monoclinic with space group P121/n1 and the unit cell dimensions are a = 8.3564(3) Å, b = 23.1321(8) Å, c = 11.9984(4) Å.

Synthesis, Characterization and Crystal Structures of N′-(5-Bromo-2-hydroxybenzylidene)-2-fluorobenzohydrazide in Unsolvated and Monohydrate Forms

A new hydrazone derivative, N′-(5-bromo-2-hydroxybenzylidene)-2-fluorobenzohydrazide (BFBH), has been prepared and crystallized from absolute methanol and 95% ethanol, respectively, yielding unsolvated and monohydrate forms of the compound, viz. BFBH (1) and BFBH·H2O (2). The two forms of the compound were characterized by elemental analysis, IR spectra, 1HNMR spectra, and X-ray single crystal structural determination. The unsolvated form of the compound crystallizes in the monoclinic space group P21/c with unit cell dimensions a = 6.879(1) A, b = 28.911(2) A, c = 8.724(1) A, β = 127.685(2)o, V = 1373.1(3) Ǻ3, Z = 4, R 1 = 0.0569, and wR 2 = 0.1352. The monohydrate forms of the compound crystallizes in the monoclinic space group P21/c with unit cell dimensions a = 14.873(3) A, b = 7.265(1) A, c = 13.043(2) A, β = 96.281(2)o, V = 1400.9(4) Ǻ3, Z = 4, R 1 = 0.0402, and wR 2 = 0.0890. The two structures are similar to each other, except for the presence of a water molecule in (2). A new hydrazone derivative, N′-(5-bromo-2-hydroxybenzylidene)-2-fluorobenzohydrazide, has been prepared and crystallized from absolute methanol and 95% ethanol, respectively, yielding unsolvated and monohydrate forms of the compound.

The structure of cinnamic acid and cinnamoyl azides, a unique localized π system: The electronic spectra and DFT‐treatment

AbstractThe electronic absorption spectra of cinnamic acid and some cinnamoyl azides have been recorded in absolute methanol and investigated to explore the structure of the titled compounds. Cinnamic acid and its derivatives have a double bond, CC, between the aromatic ring and the carboxyl group which disturbs the π electron system of the molecule and inhibits electron delocalization as compared with styrene or benzoic acid. The azide group is neither a strong electron donor nor a strong electron acceptor but it increases conjugation in the molecule. The observed spectra confirm that each of the cinnamic acid and cinnamoyl azide molecules is one of a kind of unique disturbed π‐system and not of different independent π systems, each on a fragment of the molecule as predicted by the quantum theory of atom in molecule calculations. The spectra of cinnamic acid and its derivatives are not the additive spectra of the different fragments of the molecule. The spectra are characterized by few number, low intensity, and high‐energy electronic transitions (absorption bands) in the UV‐vis region. Molecular orbital calculations confirmed the spectral observations. The optimized geometry of the ground state of the studied compounds is calculated using the DFT/B3LYP/6‐31G** level of theory and an explicit molecular orbital analysis is carried out. Excited states are calculated using the TD/DFT procedure as implemented by the Gamess 2009 package of programs. The correspondence between calculated and the observed transition energies is adequate. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012

Rapid paper chromatographic separation of [14C] angiotensen II from some metabolites: application to organ distribution.

A rapid, inexpensive method for the separation of 5-1-isoleucyl[14C] angiotensin II (A-II) from its various metabolites has been devised. A-II was extracted from tissues with absolute methanol (recovery 96%) and paper chromatographed in a butanol-acetic acid-water (18:2:5) medium for two ascents at 60 degrees C. The resulting RF for A-II of 0.45 was then compared with the RF values of three A-II metabolites produced by enzymatic degradation of the 14C-A-II and [14C]isoleucine. Trypsin degradation produced the [14C]hexapeptide metabolite, chymotryptic degradation produced the [14C]tetrapeptide metabolite and carboxypeptidase A degradation produced the [14C]heptapeptide. Increases in temperature produced a continuous increase in RF values for all the substances examined but the resolution decreased above 60 degrees C. Similarly, increases in the temperature caused the appearance of secondary peaks with some but not all peptides. The tryptic digest (hexapeptide) and the chymotryptic digest (tetrapeptide) are apparently acid- and heat-stable under the experimental conditions. All of the peptides examined failed to produce secondary peaks when heated at neutral pH. The method was used to study the tissue distribution of 14C-A-II after intravenous injection.

Solvent effects on antioxidant properties of persimmon (Diospyros kaki L. cv. Daebong) seeds

SummaryThe aim of this study was to investigate the antioxidant activities of persimmon seed extracts (PSE) using different solvents such as ethanol, methanol, acetone, and their aqueous 80% solvents. The EC50 values of the extracts from absolute ethanol (EE) and methanol (ME) in 2, 2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical–scavenging assay were 49.71 and 51.15 μg mL−1, respectively, while the EC50 of butylated hydroxyanisole (BHA) was 70.82 μg mL−1. However, the EC50 value of reducing power for the absolute acetone extract (AE) was higher (210.06 μg mL−1) than that of BHA (212.67 μg mL−1). Although the absolute ME had the highest antioxidant activity, it exhibited the lowest total phenolics and flavonoids. In contrast, the antioxidant activities of the aqueous solvent extracts showed a good correlation with total phenolics and flavonoids when compared to the absolute solvent extracts. The results showed that PSE could potentially be used as an inexpensive source of natural antioxidant in food and pharmaceutical industries.

A colorimetric method for the evaluation of anti-giardial drugs in vitro

The aim of this study was to develop a simple and reliable method to determine the viability of Giardia intestinalis after incubation with an anti-giardial agent by using a colorimetric method. Factors that may affect the optical density value were systematically evaluated. The most suitable conditions were obtained when G. intestinalis trophozoites, 5×105cells/ml were incubated with the anti-giardial agent for 48h. The culture medium was removed and trophozoites were immediately fixed by immersing the whole plate in absolute methanol for 2min. The fixed trophozoites were then stained with 0.1% w/v methylene blue for 10min, washed once by immersing the whole plate into distilled water. The dye was released by adding 0.1M hydrochloric acid solution (300μl) and the optical density was read at 655nm. The 50% inhibitory concentration values (IC50) of metronidazole, ornidazole and furazolidone obtained from our proposed method (0.41±0.06, 0.18±0.01, 0.26±0.13μg/ml, respectively) were comparable to the IC50 values obtained by the current conventional method (0.14±0.05, 0.15±0.04, 0.14±0.02μg/ml, respectively). This new method did provide a convenient and reliable way to screen for potential anti-giardial agents.

Micronuclei in the blood and bone marrow cells of mice exposed to specific complex time‐varying pulsed magnetic fields

For 8 weeks, adult CD-1 male mice were continuously exposed to complex time-varying pulsed magnetic fields (PMF) generated in the horizontal direction by a set of square Helmholtz coils. The PMF were <1000 Hz and delivered at a peak flux density of 1 mT. Sham-exposed mice were kept in a similar exposure system without a PMF. Positive control animals exposed to 1 Gy gamma radiation were also included in the study. Blood samples were collected before (time 0) and at 2, 4, 6, and 8 weeks. All mice were euthanized at the end of 8 weeks and their bone marrow was collected. From each blood and bone marrow sample, smears were prepared on microscope slides, fixed in absolute methanol, air-dried, and stained with acridine orange. All slides were coded and examined using a fluorescence microscope. The extent of genotoxicity and cytotoxicity was assessed from the incidence of micronuclei (MN) and percent polychromatic erythrocytes (PCE) in the blood and bone marrow, respectively. The data indicated that both indices in PMF-exposed mice were not significantly different from those observed in sham-exposed animals. In contrast, positive control mice exhibited significantly increased MN, and decreased percentages of PCE in both tissues. Thus, the overall data suggested that 8 weeks of continuous exposure to PMF did not induce significantly increased genotoxicity and cytotoxicity in experimental mice. Further investigations are underway using other genotoxicity assays (comet assay, gamma-H2AX foci, and chromosomal aberrations) to assess genotoxicity following PMF exposure.

Cancer/Testis Antigen CAGE Exerts Negative Regulation on p53 Expression through HDAC2 and Confers Resistance to Anti-cancer Drugs

The role of the cancer/testis antigen CAGE in drug resistance was investigated. The drug-resistant human melanoma Malme3M (Malme3M(R)) and the human hepatic cancer cell line SNU387 (SNU387(R)) showed in vivo drug resistance and CAGE induction. Induction of CAGE resulted from decreased expression and thereby displacement of DNA methyltransferase 1(DNMT1) from CAGE promoter sequences. Various drugs induce expression of CAGE by decreasing expression of DNMT1, and hypomethylation of CAGE was correlated with the increased expression of CAGE. Down-regulation of CAGE in these cell lines decreased invasion and enhanced drug sensitivity resulting from increased apoptosis. Down-regulation of CAGE also led to decreased anchorage-independent growth. Down-regulation of CAGE led to increased expression of p53, suggesting that CAGE may act as a negative regulator of p53. Down-regulation of p53 enhanced resistance to drugs and prevented drugs from exerting apoptotic effects. In SNU387(R) cells, CAGE induced the interaction between histone deacetylase 2 (HDAC2) and Snail, which exerted a negative effect on p53 expression. Chromatin immunoprecipitation assay showed that CAGE, through interaction with HDAC2, exerted a negative effect on p53 expression in Malme3M(R) cells. These results suggest that CAGE confers drug resistance by regulating expression of p53 through HDAC2. Taken together, these results show the potential value of CAGE as a target for the development of cancer therapeutics.

Ohr (Organic Hydroperoxide Resistance Protein) Possesses a Previously Undescribed Activity, Lipoyl-dependent Peroxidase

The Ohr (organic hydroperoxide resistance) family of 15-kDa Cys-based, thiol-dependent peroxidases is central to the bacterial response to stress induced by organic hydroperoxides but not by hydrogen peroxide. Ohr has a unique three-dimensional structure and requires dithiols, but not monothiols, to support its activity. However, the physiological reducing system of Ohr has not yet been identified. Here we show that lipoylated enzymes present in the bacterial extracts of Xylella fastidiosa interacted physically and functionally with this Cys-based peroxidase, whereas thioredoxin and glutathione systems failed to support Ohr peroxidase activity. Furthermore, we could reconstitute in vitro three lipoyl-dependent systems as the Ohr physiological reducing systems. We also showed that OsmC from Escherichia coli, an orthologue of Ohr from Xylella fastidiosa, is specifically reduced by lipoyl-dependent systems. These results represent the first description of a Cys-based peroxidase that is directly reduced by lipoylated enzymes.

Anti-inflammatory, anti-angiogenic, and anti-nociceptive activities of the chloroform fraction of a methanol extract from Rosa davurica Pall. leaves in experimental animal models

Rosa davurica Pall. has been traditionally used to treat inflammatory diseases and tumors. Its dried leaves were extracted with absolute methanol, and the methanol extract was successively fractionated into n-hexane, chloroform, ethyl acetate, n-butanol, and aqueous fractions. Anti-angiogenic and anti-nociceptive activities were determined using the chick embryo chorioallantoic membrane (CAM) assay and acetic acid-induced writhing response, respectively. Anti-inflammatory activity was evaluated using two in vivo mouse models, acetic acid-induced vascular permeability and carrageenan-induced inflammation in the air-pouch. The methanol extract gave rise to significant inhibition in the CAM angiogenesis, and showed marked 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. Among the fractions prepared from the methanol extract, the chloroform fraction exhibited highest inhibitory effect in the CAM angiogenesis. The chloroform fraction displayed anti-inflammatory activities in vascular permeability and air-pouch models. In the air-pouch model, it was able to diminish exudate volume, number of polymorphonulcear leukocytes, and nitrite content. It also showed anti-nociceptive activity in the writhing response model in mice. The leaves of R. davurica possess anti-angiogenic and related anti-inflammatory and anti-nociceptive activities, which would provide some therapeutic support on its traditional use.

Evaluation of Antioxidant Properties of Phenolics Extracted from Ananas comosus L.

Phenolics were extracted from the fruit tissues of Ananas comosus L. var. queen, cv. ‘Meitei Keehom’, a variety of pineapple grown in Manipur, India, after skin peeling, purified and their antioxidant properties were analyzed. The antioxidant properties were assessed based on the ability of fruit phenolics in absolute methanol to scavenge DPPH, superoxide anion radicals and hydroxyl radicals and compared to antioxidant compounds like ascorbic acid and pyragallol. Pineapple fruit phenolics scavenged DPPH, superioxide anion radicals and hydroxyl radicals in a dose dependent way. In DPPH assay, the IC50 values of pineapple phenolics, ascorbic acid and pyragallol were 12.2μg/ml, 17.82μg/ml and 15.92μg/ml respectively. In superoxide anion and hydroxyl radical scavenging activities, the IC50 values of pineapple phenolics were 11.42μg/ml and 55.292μg/ml, for ascorbic acid 49.62μg/ml, 48.52μg/ml and that of pyragallol was 15.672μg/ ml and 60.62μg/ml. The IC50 value was lowest in pineapple phenolics than ascorbic acid and pyragallol in DPPH and superoxide anion assays. But it is higher than ascorbic acid and lower than pyragallol in hydroxyl radical assay. The lower the IC50 values, the higher the antioxidant activities. The phenolics extracted from this variety of pineapple exhibit excellent free radical scavenging activity. The result shows that pineapple and its active constituents may be used in further antioxidative therapy.