Displaying publications 1 - 20 of 49 in total

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  1. Abdul Karim N', Wan Ibrahim WA, Sanagi MM, Abdul Keyon AS
    Electrophoresis, 2016 10;37(20):2649-2656.
    PMID: 27434368 DOI: 10.1002/elps.201600207
    Online preconcentration using electrokinetic supercharging (EKS) was proposed to enhance the sensitivity of separation for endocrine disrupting chemical (methylparaben (MP)) and phenolic pollutants (2-nitrophenol (NP) and 4-chlorophenol (CP)) in water sample. Important EKS and separation conditions such as the concentration of BGE; the choice of terminating electrolyte (TE); and the injection time of leading electrolyte (LE), sample, and TE were optimized. The optimum EKS-CE conditions were as follows: BGE comprising of 12 mM sodium tetraborate pH 10.1, 100 mM sodium chloride as LE hydrodynamically injected at 50 mbar for 30 s, electrokinetic injection (EKI) of sample at -3 kV for 200 s, and 100 mM CHES as TE hydrodynamically injected at 50 mbar for 40 s. The separation was conducted at negative polarity mode and UV detection at 214 nm. Under these conditions, the sensitivity of analytes was enhanced from 100- to 737-fold as compared to normal CZE with hydrodynamic injection, giving LOD of 4.89, 5.29, and 53 μg/L for MP, NP and CP, respectively. The LODs were adequate for the analysis of NP and CP in environmental water sample having concentration at or lower than their maximum admissible concentration limit (240 and 2000 μg/L for NP and CP). The LOD of MP can be suitable for the analysis of MP exists at mid-microgram per liter level, even though the LOD was slightly higher than the concentration usually found in water samples (from ng/L to 1 μg/L). The method repeatabilities (%RSD) were in the range of 1.07-2.39% (migration time) and 8.28-14.0% (peak area).
    Matched MeSH terms: Phenols/isolation & purification*
  2. Ahmad T, Bustam MA, Irfan M, Moniruzzaman M, Asghar HMA, Bhattacharjee S
    Biotechnol Appl Biochem, 2019 Jul;66(4):698-708.
    PMID: 31172593 DOI: 10.1002/bab.1787
    Phytosynthesis of gold nanoparticles (AuNPs) has achieved an indispensable significance due to the diverse roles played by biomolecules in directing the physiochemical characteristics of biosynthesized nanoparticles. Therefore, the precise identification of key bioactive compounds involved in producing AuNPs is vital to control their tunable characteristics for potential applications. Herein, qualitative and quantitative determination of key biocompounds contributing to the formation of AuNPs using aqueous Elaeis guineensis leaves extract is reported. Moreover, roles of phenolic compounds and flavonoids in reduction of Au3+ and stabilization of AuNPs have been elucidated by establishing a reaction mechanism. Fourier-transform infrared spectroscopy (FTIR) showed shifting of O─H stretching vibrations toward longer wavenumbers and C═O toward shorter wavenumbers due to involvement of polyphenolic compounds in biosynthesis and oxidation of polyphenolic into carboxylic compounds, respectively, which cape nanoparticles to inhibit the aggregation. Congruently, pyrolysis-gas chromatography-mass spectrometry revealed the major contribution of polyphenolic compounds in the synthesis of AuNPs, which was further endorsed by reduction of total phenolic and total flavonoids contents from 48.08 ± 1.98 to 9.59 ± 0.92 mg GAE/g and 32.02 ± 1.31 to 13.8 ± 0.97 mg CE/g within 60 Min, respectively. Based on experimental results, reaction mechanism explained the roles of phenolic compounds and flavonoids in producing spherical-shaped AuNPs.
    Matched MeSH terms: Phenols/isolation & purification
  3. Alam MZ, Muyibi SA, Mansor MF, Wahid R
    J Environ Sci (China), 2006;18(3):446-52.
    PMID: 17294638
    The study was attempted to produce activated carbons from palm oil mill effluent (POME) sludge. The adsorption capacity of the activated carbons produced was evaluated in aqueous solution of phenol. Two types of activation were followed, namely, thermal activation at 300, 500 and 800 degrees C, and physical activation at 15 degrees C (boiling treatment). A control (raw POME sludge) was used to compare the adsorption capacity of the activated carbons produced. The results indicated that the activation temperature of 800 degrees C showed maximum absorption capacity by the activated carbon (POME 800) in aqueous solution of phenol. Batch adsorption studies showed an equilibrium time of 6 h for the activated carbon of POME 800. It was observed that the adsorption capacity was higher at lower values of pH (2-3) and higher value of initial concentration of phenol (200-300 mg/L). The equilibrium data were fitted by the Langmuir and Freundlich adsorption isotherms. The adsorption of phenol onto the activated carbon POME 800 was studied in terms of pseudo- first and second order kinetics to predict the rate constant and equilibrium capacity with the effect of initial phenol concentrations. The rate of adsorption was found to be better correlation for the pseudo-second order kinetics compared to the first order kinetics.
    Matched MeSH terms: Phenols/isolation & purification
  4. Alam N, Hossain M, Khalil MI, Moniruzzaman M, Sulaiman SA, Gan SH
    PMID: 21854608 DOI: 10.1186/1472-6882-11-65
    Withania somnifera is an important medicinal plant traditionally used in the treatment of many diseases. The present study was carried out to characterize the phenolic acids, flavonoids and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activities in methanolic extracts of W. somnifera fruits, roots and leaves (WSFEt, WSREt and WSLEt).
    Matched MeSH terms: Phenols/isolation & purification
  5. Aung HH, Chia LS, Goh NK, Chia TF, Ahmed AA, Pare PW, et al.
    Fitoterapia, 2002 Aug;73(5):445-7.
    PMID: 12165348
    Plumbagin, isoshinanolone, epishinanolone, shinanolone, quercetin and kaempferol were isolated from the leaves of Nepenthes gracilis. Spectral data of shinanolone are presented.
    Matched MeSH terms: Phenols/isolation & purification*
  6. Bujang JS, Zakaria MH, Ramaiya SD
    PLoS One, 2021;16(2):e0247327.
    PMID: 33626109 DOI: 10.1371/journal.pone.0247327
    Currently, bee-gathered pollen (bee pollen) is commonly used worldwide as a dietary supplement and is recognized for its curative properties. Floral pollen is also important but is less recognized due to a lack of investigation. This study aims to determine the morphological characteristics and nutritional and phytochemical properties of floral maize pollen. Fresh pollen grains harvested from a farm of maize plants are yellow in colour and spheroid in shape. They change to amber and indented prismatic solid shapes when dehydrated. The main composition of floral maize pollen is carbohydrates (44.30±3.73%), followed by moisture (23.38±5.73%), crude proteins (17.16±3.13%), crude fibres (9.56±0.92%), and ash (4.98±0.11%), while the lowest content is observed for crude fats (0.62±0.06%). The predominant mineral is potassium (768.50±11.40 mg 100 g-1), followed by sodium (695.10±9.70 mg 100 g-1), calcium (147.20±12.60 mg 100 g-1), and magnesium (97.30±2.9 mg 100 g-1). The microelements (with average values) consist of iron (49.50±3.30 mg 100 g-1) and zinc (30.00±3.70 mg 100 g-1). Excellent phytochemical properties add value to floral maize pollen. Maize pollen contains a high total phenolic content (TPC) and total flavonoid content (TFC) of 783.02 mg GAE 100 g-1 and 1706.83 mg QE 100 g-1, respectively, and possesses strong antioxidant activity of 10.54 mg mL-1. Maize floral pollen and derived products can serve as future food resources for human consumption and as a source of functional and bioactive compounds in nutraceutical and pharmaceutical industries.
    Matched MeSH terms: Phenols/isolation & purification
  7. Chew YL, Lim YY, Stanslas J, Ee GC, Goh JK
    PMID: 25371595
    BACKGROUND: Flowers of Bauhinia kockiana were investigated for their anticancer properties.

    METHODS: Gallic acid (1), and methyl gallate (2), were isolated via bioassay-directed isolation, and they exhibited anticancer properties towards several cancer cell lines, examined using MTT cell viability assay. Pyrogallol (3) was examined against the same cancer cell lines to deduce the bioactive functional group of the phenolic compounds.

    RESULTS: The results showed that the phenolic compounds could exhibit moderate to weak cytotoxicity towards certain cell lines (GI50 30 - 86 µM), but were inactive towards DU145 prostate cancer cell (GI50 > 100 µM).

    CONCLUSION: It was observed that pyrogallol moiety was one of the essential functional structures of the phenolic compounds in exhibiting anticancer activity. Also, the carboxyl group of compound 1 was also important in anticancer activity. Examination of the PC-3 cells treated with compound 1 using fluorescence microscopy showed that PC-3 cells were killed by apoptosis.

    Matched MeSH terms: Phenols/isolation & purification
  8. Choong CE, Ibrahim S, Basirun WJ
    J Colloid Interface Sci, 2019 Apr 01;541:12-17.
    PMID: 30682589 DOI: 10.1016/j.jcis.2019.01.071
    The present study reports the removal of Bisphenol A (BPA) and Ibuprofen (IBP) using adsorbents prepared from batik sludge. The calcite sludge-aluminum hydroxide (CAl) adsorbent was prepared by calcination and followed by aluminum hydroxide impregnation. The batik sludge and prepared adsorbents were characterized by FESEM, TGA, XRD, FTIR and BET techniques. The maximum adsorption capacity, adsorption time, different initial solution pH, ionic strength and regeneration study of the adsorbents were also investigated. Furthermore, the sorption behavior of the pollutants were studied by the Langmuir and Freundlich isotherms. The deposition of Al(OH)3 enhanced the BPA and IBP adsorption capacity on the CAl surface. The maximum removal capacity of BPA and Ibuprofen were 83.53 mg g-1 and 34.96 mg g-1 for the CAl adsorbent. In addition, the kinetic data for BPA and IBP were fitted to the pseudo first order, pseudo second order, Elovich, parabolic diffusion and power function equations to understand the sorption behavior. The adsorption behavior of BPA and IBP was mainly chemisorption. This study shows that CAl is a promising adsorbent for the removal of BPA and IBP.
    Matched MeSH terms: Phenols/isolation & purification*
  9. Djebli N, Mustafa MR, Keskin M, Kolayli S
    Comb Chem High Throughput Screen, 2021;24(10):1664-1670.
    PMID: 33208062 DOI: 10.2174/1386207323999201117114008
    AIM AND OBJECTIVE: This study aimed at investigating the gastro-protective effects of Algerian Sahara (Sidr) honey from Apis mellifera intermissa against HCl/Ethanol-induced gastric ulcers in rats.

    MATERIALS AND METHODS: Total phenolic content, antioxidant activity and phenolic compounds were determined. Then, three groups of rats (control, HCl/ Ethanol-induced ulcer, and orally administered honey) were used for the determination of gastro-protective effect of Sidr honey.

    RESULTS: Total phenolic content, total flavonoid content, and DPPH activity of the honey sample were determined as 47.35±3.35 mg GAE/ 100 g, 2.13±0.17 mg QE/ 100 g, and 229.24±0.02 mg/mL, respectively. Oral pretreatment of rats with honey (1.2 g/Kg body weight orally at an interval of 2 days) protected gastric mucosa against HCl/Ethanol-induced damage by decreasing ulcer score, the volume and acidity of gastric juice and increasing pH.

    CONCLUSION: These results were confirmed by the histological assessment, which demonstrated a significant gastro-protective activity of Saharian (Sidr) honey against HCl/Ethanol-induced stomach ulcer. Plasma tumor necrosis factor-α, IL-6 and PGE2 were also measured. Sahara honey significantly decreased the plasma TNF-α, PGE2, and IL-6 concentrations.

    Matched MeSH terms: Phenols/isolation & purification
  10. Eseyin OA, Sattar MA, Rathore HA, Aigbe F, Afzal S, Ahmad A, et al.
    Pak J Pharm Sci, 2018 Jan;31(1):45-50.
    PMID: 29348083
    Telfairia occidentalis possesses high antioxidant activity. However, the antioxidant components of the plant have not yet been identified. This study was undertaken to identify the phenolics in the leaf of the plant. Extract and fractions of the leaf of the plant were analysed using the HPLC and GCMS. HPLC analysis revealed the presence of gallic acid (22.19μg/mg), catechin (29.17μg/mg), caffeic acid (9.17μg/mg), ferulic acid (0.94μg/mg), sinapic acid (1.91 μg/mg) and 4-hydroxy benzoic acid (43.86 μg/mg) in the aqueous extract. Phenolics fraction contained gallic acid (0.88 μg/mg), catechin (2.70μg/mg), caffeic acid (7.92μg/mg), ferulic acid (2.72μg/mg), benzoic acid (6.36μg/mg), p-coumaric acid (1.48μg/mg), quercetin (12.00μg/mg). Only caffeic acid (2.50μg/mg), ferulic acid (0.44μg/mg) and quercetin (8.50μg/mg) were detected in the flavonoid fraction. While GCMS analysis showed the presence of methylparaben; ethylparaben; benzoic acid; 4-hydroxy-2-methoxy-3,5,6-trimethyl-, methyl ester; 4-hydroxy-3-methoxy; phenol, 5-methoxy-2-(methoxymethyl)-; phenol, 5-methoxy-2, 3- dimethyl; and phenol, 2-(2-benzothiazolyl)-. This study is the first to reveal the identity of some phenolics components of the leaf of Telfairia occidentalis.
    Matched MeSH terms: Phenols/isolation & purification*
  11. Gođevac D, Stanković J, Novaković M, Anđelković B, Dajić-Stevanović Z, Petrović M, et al.
    J Nat Prod, 2015 Sep 25;78(9):2198-204.
    PMID: 26290401 DOI: 10.1021/acs.jnatprod.5b00273
    From the aerial parts of Atriplex littoralis, three new flavonoid glycosides named atriplexins I-III (1-3), a known flavonoid glycoside, spinacetin 3-O-β-d-glucopyranoside (4), arbutin (5), and 4-hydroxybenzyl-β-d-glucopyranoside (6) were isolated. Their structures were elucidated on the basis of detailed spectroscopic analysis, including 1D and 2D NMR (COSY, NOESY, TOCSY, HSQC, HMBC) and HRESITOF MS data. The compounds were tested for in vitro protective effects on chromosome aberrations in peripheral human lymphocytes using a cytochalasin-B-blocked micronucleus (MN) assay in a concentration range of 0.8-7.4 μM of final culture solution. Chromosomal damage was induced by 2 Gy of γ-radiation on binucleated human lymphocytes, and the effects of the compounds were tested 2 to 19 h after irradiation. The frequency of micronuclei (MNi) was scored in binucleated cells, and the nuclear proliferation index was calculated. The highest prevention of in vitro biochemical and cytogenetic damage of human lymphocytes induced by γ-radiation was exhibited by 3 (reduction of MN frequency by 31%), followed by 4 and 6.
    Matched MeSH terms: Phenols/isolation & purification*
  12. Hameed BH, Rahman AA
    J Hazard Mater, 2008 Dec 30;160(2-3):576-81.
    PMID: 18434009 DOI: 10.1016/j.jhazmat.2008.03.028
    Activated carbon derived from rattan sawdust (ACR) was evaluated for its ability to remove phenol from an aqueous solution in a batch process. Equilibrium studies were conducted in the range of 25-200mg/L initial phenol concentrations, 3-10 solution pH and at temperature of 30 degrees C. The experimental data were analyzed by the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. Equilibrium data fitted well to the Langmuir model with a maximum adsorption capacity of 149.25mg/g. The dimensionless separation factor RL revealed the favorable nature of the isotherm of the phenol-activated carbon system. The pseudo-second-order kinetic model best described the adsorption process. The results proved that the prepared activated carbon was an effective adsorbent for removal of phenol from aqueous solution.
    Matched MeSH terms: Phenols/isolation & purification*
  13. Iqbal M, Shah MD, Lie CA, San CK
    Mol Cell Biochem, 2010 Aug;341(1-2):271-7.
    PMID: 20376534 DOI: 10.1007/s11010-010-0458-x
    This study was aimed to evaluate the effect of Strobilanthes crispus extract for possible protection against lipid peroxidation and DNA damage induced by iron nitrilotriacetate (Fe-NTA) and hydrogen peroxide (H(2)O(2)). Fe-NTA is a potent nephrotoxic agent and induces acute and subacute renal proximal tubular necrosis by catalyzing the decomposition of H(2)O(2)-derived production of hydroxyl radicals, which are known to cause lipid peroxidation and DNA damage. Incubation of postmitochondrial supernatant and/or calf thymus DNA with H(2)O(2) (40 mM) in the presence of Fe-NTA (0.1 mM) induces lipid peroxidation and DNA damage to about 2.3-fold and 2.9-fold, respectively, as compared to control (P < 0.05). In lipid peroxidation protection studies, S. crispus treatment showed a dose-dependent inhibition (45-53% inhibition, P < 0.05) of Fe-NTA and H(2)O(2) induced lipid peroxidation. Similarly, in DNA damage protection studies, S. crispus treatment also showed a dose-dependent inhibition (18-30% inhibition, P < 0.05) of DNA damage. In addition, the protection was closely related to the content of phenolic compounds as evident by S. crispus extract showing the value of 124.48 mg/g total phenolics expressed as gallic acid equivalent (GAE, mg/g of extract). From these studies, it is concluded that S. crispus inhibits peroxidation of membrane lipids and DNA damage induced by Fe-NTA and H(2)O(2) and possesses the potential to be used to treat or prevent degenerative diseases where oxidative stress is implicated.
    Matched MeSH terms: Phenols/isolation & purification
  14. Jalal TK, Ahmed IA, Mikail M, Momand L, Draman S, Isa ML, et al.
    Appl Biochem Biotechnol, 2015 Apr;175(7):3231-43.
    PMID: 25649443 DOI: 10.1007/s12010-015-1499-0
    Artocarpus altilis (breadfruit) pulp, peel and whole fruit were extracted with various solvents such as hexane, dichloromethane (DCM) and methanol. The antioxidant activity of these extracts were examined using the stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test. IC50 was 55 ± 5.89 μg/ml for the pulp part of methanol extract. In the β-carotene bleaching assay, the antioxidant activity was 90.02 ± 1.51 % for the positive control (Trolox) and 88.34 ± 1.31 % for the pulp part of the fruit methanol extract. The total phenolic content of the crude extracts was determined using the Folin-Ciocalteu procedure; methanol pulp part demonstrated the highest phenol content value of 781 ± 52.97 mg GAE/g of dry sample. While the total flavonoid content was determined using the aluminium chloride colorimetric assay, the highest value of 6213.33 ± 142.22 mg QE/g was indicated by pulp part of the fruit methanol extract. The antimicrobial activity of the crude extracts was tested using disc diffusion method against pathogenic microorganisms: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Salmonella typhimurium, Escherichia coli, Klebsiella pneumonia and Candida albicans. Methanol extract of pulp part was recorded to have the highest zone of inhibition against Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration (MIC) and MBC/minimal fungicidal concentration (MFC) for the extracts were also determined using the microdilution method ranging from 4000 to 63 μg/ml against pathogenic microbes. The MBC/MFC values varied from 250 to 4000 μg/ml. A correlation between antioxidant activity assays, antimicrobial activity and phenolic content was established. The results shows that the various parts of A. altilis fruit extracts promising antioxidant activities have potential bioactivities due to high content of phenolic compounds.
    Matched MeSH terms: Phenols/isolation & purification
  15. Jothy SL, Zakaria Z, Chen Y, Lau YL, Latha LY, Shin LN, et al.
    Molecules, 2011 Sep 05;16(9):7583-92.
    PMID: 21894090 DOI: 10.3390/molecules16097583
    BACKGROUND AND OBJECTIVE: Cassia fistula L belongs to the family Leguminosae, and it is one of the most popular herbal products in tropical countries. C. fistula seeds have been used as a herbal medicine and have pharmacological activity which includes anti-bacterial, anti-fungal, and antioxidant properties. The goal of this study was to identify compounds from C. fistula seeds which are responsible for anti-Candida albicans activity using bioassay-directed isolation.

    RESULTS: The preliminary phytochemical screening of the plant seed revealed the presence of anthraquinones, flavonoids, saponins, tannins and terpenoids. The isolation of active compounds was carried out in four steps: multiple extractions, fractionation using column chromatography and purification using preparative thin-layer chromatography (TLC) and liquid chromatography/mass spectrometry (LC/MS). The structure of separated compounds was determined on the basis of mass spectrometry data. One compound was identified is roseanone.

    CONCLUSIONS: The MS analysis on the active fraction from seed extract of C. fistula confirmed the presence of roseanone with antiyeast activity.

    Matched MeSH terms: Phenols/isolation & purification
  16. Kho YS, Vikineswary S, Abdullah N, Kuppusamy UR, Oh HI
    J Med Food, 2009 Feb;12(1):167-74.
    PMID: 19298211 DOI: 10.1089/jmf.2007.0568
    Auricularia auricula-judae is currently grown in Malaysia. In the present study, the methanolic extracts from fruit bodies (fresh, oven-dried, and freeze-dried) and mycelium of A. auricula-judae were evaluated for their antioxidant capacities based on 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity and ferric reducing antioxidant power (FRAP) assay. The total phenolic content in the extracts were also measured. The extract of freeze-dried fruit bodies of A. auricula-judae had potent DPPH free radical scavenging activity with a 50% effective concentration of 2.87 mg/mL, whereas the FRAP value of A. auricula-judae mycelium was 5.22 micromol of FeSO(4).7H(2)O equivalents/g of mycelium sample. Further, a positive correlation (R(2) = 0.7668) between FRAP level of A. auricula-judae extracts and the total phenolic contents was observed. Thus the method of processing of fresh fruit bodies had an effect on the antioxidant potential of A. auricula-judae.
    Matched MeSH terms: Phenols/isolation & purification
  17. Khoo HE, Azlan A, Ismail A, Abas F
    Molecules, 2012 Aug 14;17(8):9754-73.
    PMID: 22893021 DOI: 10.3390/molecules17089754
    Solid phase extraction (SPE) using Sep-Pak® cartridges is one of the techniques used for fractionation of antioxidant compounds in waste of dabai oil extraction (defatted dabai parts). The aim of this study was to determine the phenolic compounds and antioxidant capacity in crude extracts and several SPE fractions from methanolic extract of defatted dabai pulp and peel. Based on SPE, Sep-Pak® cyanopropyl and C₁₈ cartridges were used to fractionate the antioxidant-rich crude extracts into water and methanolic fractions. Analyzed using LC-MS, flavonoids, anthocyanins, saponin derivatives and other unknown antioxidative compounds were detected in the defatted dabai crude extracts and their SPE fractions. Anthocyanins were the major phenolic compounds identified in the defatted dabai peel and detected in most of the SPE fractions. Methanolic fractions of defatted dabai parts embraced higher total phenolics and antioxidant capacity than water fractions. This finding also revealed the crude extracts of defatted dabai peel have the most significant antioxidant properties compared to the methanolic and water fractions studied. The crude extract of defatted dabai parts remain as the most potent antioxidant as it contains mixture of flavonoids, anthocyanins and other potential antioxidants.
    Matched MeSH terms: Phenols/isolation & purification
  18. Khorasani Esmaeili A, Mat Taha R, Mohajer S, Banisalam B
    Biomed Res Int, 2015;2015:643285.
    PMID: 26064936 DOI: 10.1155/2015/643285
    In the present study the extracts of in vivo and in vitro grown plants as well as callus tissue of red clover were tested for their antioxidant activities, using different extraction solvent and different antioxidant assays. The total flavonoid and phenolic contents as well as extraction yield of the extracts were also investigated to determine their correlation with the antioxidant activity of the extracts. Among all the tested extracts the highest amounts of total phenolic and total flavonoids content were found in methanol extract of in vivo grown plants. The antioxidant activity of tested samples followed the order in vivo plant extract > callus extract > in vitro extract. The highest reducing power, 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging, and chelating power were found in methanol extracts of in vivo grown red clover, while the chloroform fraction of in vivo grown plants showed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, superoxide anion radical scavenging and hydrogen peroxide scavenging compared to the other tested extracts. A significant correlation was found between the antioxidant activity of extracts and their total phenolic and total flavonoid content. According to the findings, the extract of in vitro culture of red clover especially the callus tissue possesses a comparable antioxidant activity to the in vivo cultured plants' extract.
    Matched MeSH terms: Phenols/isolation & purification
  19. Lee KM, Lim PE
    Chemosphere, 2005 Jan;58(4):407-16.
    PMID: 15620732
    The role of bioregeneration process in renewing the adsorbent surface for further adsorption of organics during simultaneous adsorption and biodegradation processes has been well recognized. The extent of bioregeneration of powdered activated carbon (PAC) as an adsorbent loaded with phenol, p-methylphenol, p-ethylphenol and p-isopropylphenol, respectively, in the simultaneous adsorption and biodegradation processes were quantitatively determined using oxygen uptake as a measure of substrate consumption. Bioregeneration phenomenon was also evaluated in the simultaneous adsorption and biodegradation processes under sequencing batch reactor (SBR) operation to treat synthetic wastewater containing 1200 mg l(-1) phenol and p-methylphenol, respectively. The SBR systems were operated with FILL, REACT, SETTLE, DRAW and IDLE periods in the ratio of 4:6:1:0.75:0.25 for a cycle time of 12 h. The results show that the percentage of desorption from loaded PAC decreased in the order phenol>p-methylphenol>p-ethylphenol>p-isopropylphenol. For the treatment of phenol and p-methylphenol in the SBR reactors, respectively, the simultaneous adsorption and biodegradation processes were able to produce a consistent effluent quality of COD < or = 100 mg l(-1) when the applied PAC dosage was 0.115 and 0.143 g PAC per cycle, respectively. When no further PAC was added, the treatment performance deteriorated to that of the case without PAC addition after 68 and 48 cycles of SBR operation, respectively, for phenol and p-methylphenol. This observation is consistent with the greater extent of bioregeneration for phenol-loaded PAC as compared to p-methylphenol-loaded PAC.
    Matched MeSH terms: Phenols/isolation & purification*
  20. Lee KM, Lim PE
    Water Sci Technol, 2003;47(10):41-7.
    PMID: 12862215
    The objective of this study is to investigate the potential of the activated rice husk to be used as an alternative adsorbent to powdered activated carbon (PAC) in the simultaneous adsorption and biodegradation processes under sequencing batch reactor (SBR) operation to treat synthetic wastewater containing phenol, p-methylphenol, p-ethylphenol and p-isopropylphenol. The rice husk (PRH) was activated by pyrolysis at 600 degrees C for 5 hours in a nitrogen atmosphere. Using the Langmuir model, the limiting adsorption capacities of PRH for the phenols were found to vary from 0.015-0.05 of those of PAC. The SBR reactors with and without adsorbent addition were operated with fill, react, settle, draw and idle periods in the ratio of 4:6:1:0.76:0.25 for a cycle time of 12 hours. For phenolic wastewater containing, 1,200 mg/L phenol, 1,200 mg/L p-methylphenol, 800 mg/L p-ethylphenol and 660 mg/L p-isopropylphenol, it was found that the biodegradation process alone was unable to produce effluent of quality which would satisfy the discharge standards of COD < or = 100 mg/L and phenol concentration < or = 1 mg/L. The addition of PAC in the ratio of PAC/phenolic compound at 0.095 g/g for phenol, 0.119 g/g for p-methylpheol, 0.179 g/g for p-ethylphenol and 0.220 g/g for p-isopropylphenol, can improve the effluent quality to satisfy the discharge standards. Equivalent treatment performance was achieved with the use of PRH at dosages of 2-3 times higher than those of PAC for all the phenolic wastewater studied. The increased adsorption capacity of PRH shown in the treatment indicates bioregeneration of the adsorbed surface during the treatment process.
    Matched MeSH terms: Phenols/isolation & purification*
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