Displaying publications 41 - 60 of 349 in total

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  1. 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: Antioxidants/chemistry*
  2. Jothy SL, Torey A, Darah I, Choong YS, Saravanan D, Chen Y, et al.
    Molecules, 2012 Aug 29;17(9):10292-305.
    PMID: 22932211 DOI: 10.3390/molecules170910292
    The genus Cassia, comprising about 600 species widely distributed worldwide is well known for its diverse biological and pharmacological properties. Cassia spectabilis (sin Senna spectabilis) (DC) Irwin et Barn (Fabaceae) is widely grown as an ornamental plant in tropical and subtropical areas. C. spectabilis has been commonly used in traditional medicine for many years. Information in the biomedical literature has indicated the presence of a variety of medicinally-important chemical constituents in C. spectabilis. Pharmacological studies by various groups of investigators have shown that C. spectabilis possesses significant biological activity, such as antibacterial, antibiofilm, antifungal and antioxidant properties. Beside this, toxicity studies of this plant have revealed no toxic effect on mice. In view of the immense medicinal importance of C. spectabilis, this review aimed at compiling all currently available information on C. spectabilis’s botany, phytochemistry, pharmacology, and mechanism of actions, toxicology and its ethnomedicinal uses.
    Matched MeSH terms: Antioxidants/chemistry
  3. Grace-Lynn C, Darah I, Chen Y, Latha LY, Jothy SL, Sasidharan S
    Molecules, 2012 Sep 19;17(9):11185-98.
    PMID: 22992785
    Lantadenes are pentacyclic triterpenoids present in the leaves of the plant Lantana camara. In the present study, in vitro antioxidant activity and free radical scavenging capacity of lantadene A was evaluated using established in vitro models such as ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picryl-hydrazyl (DPPH•), hydroxyl radical (OH•), nitric oxide radical (NO•), superoxide anion scavenging activities and ferrous ion chelating assay. Interestingly, lantadene A showed considerable in vitro antioxidant, free radical scavenging capacity activities in a dose dependant manner when compared with the standard antioxidant in nitric oxide scavenging, superoxide anion radical scavenging and ferrous ion chelating assay. These findings show that the lantadene A possesses antioxidant activity with different mechanism of actions towards the different free radicals tested. Since lantadene A is a very popular drug in modern medicine, it is a promising candidate for use as an antioxidant and hepatoprotective agent.
    Matched MeSH terms: Antioxidants/chemistry
  4. Khalil I, Moniruzzaman M, Boukraâ L, Benhanifia M, Islam A, Islam N, et al.
    Molecules, 2012 Sep 20;17(9):11199-215.
    PMID: 22996344
    The aim of the present study was to characterize the physical, biochemical and antioxidant properties of Algerian honey samples (n = 4). Physical parameters, such as pH, moisture content, electrical conductivity (EC), total dissolved solids (TDS), color intensity, total sugar and sucrose content were measured. Several biochemical and antioxidant tests were performed to determine the antioxidant properties of the honey samples. The mean pH was 3.84 ± 0.01, and moisture the content was 13.21 ± 0.16%. The mean EC was 0.636 ± 0.001, and the mean TDS was 316.92 ± 0.92. The mean color was 120.58 ± 0.64 mm Pfund, and the mean 5-hydroxymethylfurfural (HMF) content was 21.49 mg/kg. The mean total sugar and reducing sugar contents were 67.03 ± 0.68 g/mL and 64.72 ± 0.52 g/g, respectively. The mean sucrose content was 2.29 ± 0.65%. High mean values of phenolic (459.83 ± 1.92 mg gallic acid/kg), flavonoid (54.23 ± 0.62 mg catechin/kg), ascorbic acid (159.70 ± 0.78 mg/kg), AEAC (278.15 ± 4.34 mg/kg), protein (3381.83 ± 6.19 mg/kg) and proline (2131.47 ± 0.90) contents, as well as DPPH (39.57% ± 4.18) and FRAP activities [337.77 ± 1.01 µM Fe (II)/100 g], were also detected, indicating that Algerian honey has a high antioxidant potential. Strong positive correlations were found between flavonoid, proline and ascorbic acid contents and color intensity with DPPH and FRAP values. Thus, the present study revealed that Algerian honey is a good source of antioxidants.
    Matched MeSH terms: Antioxidants/chemistry*
  5. Bimakr M, Rahman RA, Taip FS, Adzahan NM, Sarker MZ, Ganjloo A
    Molecules, 2012 Oct 08;17(10):11748-62.
    PMID: 23044712 DOI: 10.3390/molecules171011748
    In the present study, ultrasound-assisted extraction of crude oil from winter melon seeds was investigated through response surface methodology (RSM). Process variables were power level (25-75%), temperature (45-55 °C) and sonication time (20-40 min). It was found that all process variables have significant (p < 0.05) effects on the response variable. A central composite design (CCD) was used to determine the optimum process conditions. Optimal conditions were identified as 65% power level, 52 °C temperature and 36 min sonication time for maximum crude yield (108.62 mg-extract/g-dried matter). The antioxidant activity, total phenolic content and fatty acid composition of extract obtained under optimized conditions were determined and compared with those of oil obtained by the Soxhlet method. It was found that crude extract yield (CEY) of ultrasound-assisted extraction was lower than that of the Soxhlet method, whereas antioxidant activity and total phenolic content of the extract obtained by ultrasound-assisted extraction were clearly higher than those of the Soxhlet extract. Furthermore, both extracts were rich in unsaturated fatty acids. The major fatty acids of the both extracts were linoleic acid and oleic acid.
    Matched MeSH terms: Antioxidants/chemistry*
  6. Ghasemzadeh A, Jaafar HZ, Karimi E
    Int J Mol Sci, 2012 Nov 13;13(11):14828-44.
    PMID: 23203096 DOI: 10.3390/ijms131114828
    The effect of foliar application of salicylic acid (SA) at different concentrations (10-3 M and 10-5 M) was investigated on the production of secondary metabolites (flavonoids), chalcone synthase (CHS) activity, antioxidant activity and anticancer activity (against breast cancer cell lines MCF-7 and MDA-MB-231) in two varieties of Malaysian ginger, namely Halia Bentong and Halia Bara. The results of high performance liquid chromatography (HPLC) analysis showed that application of SA induced the synthesis of anthocyanin and fisetin in both varieties. Anthocyanin and fisetin were not detected in the control plants. Accordingly, the concentrations of some flavonoids (rutin and apigenin) decreased significantly in plants treated with different concentrations of SA. The present study showed that SA enhanced the chalcone synthase (CHS) enzyme activity (involving flavonoid synthesis) and recorded the highest activity value of 5.77 nkat /mg protein in Halia Bara with the 10-5 M SA treatment. As the SA concentration was decreased from 10-3 M to 10-5 M, the free radical scavenging power (FRAP) increased about 23% in Halia Bentong and 10.6% in Halia Bara. At a concentration of 350 μg mL-1, the DPPH antioxidant activity recorded the highest value of 58.30%-72.90% with the 10-5 M SA treatment followed by the 10-3 M SA (52.14%-63.66%) treatment. The lowest value was recorded in the untreated control plants (42.5%-46.7%). These results indicate that SA can act not only as an inducer but also as an inhibitor of secondary metabolites. Meanwhile, the highest anticancer activity against MCF-7 and MDA-MB-231 cell lines was observed for H. Bara extracts treated with 10-5 M SA with values of 61.53 and 59.88%, respectively. The results suggest that the high anticancer activity in these varieties may be related to the high concentration of potent anticancer components including fisetin and anthocyanin. The results thus indicate that the synthesis of flavonoids in ginger can be increased by foliar application of SA in a controlled environment and that the anticancer activity in young ginger extracts could be improved.
    Matched MeSH terms: Antioxidants/chemistry
  7. Sulaiman SF, Ooi KL
    J Agric Food Chem, 2012 Nov 28;60(47):11832-8.
    PMID: 23136968 DOI: 10.1021/jf303736h
    Mature-green and ripe fleshes from 12 samples of Mangifera were selected for this study. The mature-green fleshes were found to have higher vitamin C contents than the ripe fleshes. However, not all higher total or individual phenolic contents were measured from the mature-green fleshes. The highest contents of vitamin C and total phenolics were respectively measured from the aqueous extracts of mature-green (255.86 ± 12.98 μg AAE/g sample) and ripe (142.57 ± 0.38 μg GAE/g sample) fleshes of M. petandra cv. Pauh. Gallic acid and mangiferin were detected in all aqueous extracts. The extracts of the mature-green flesh of M. indica cv. Chokanan and the ripe flesh of M. indica cv. Siku Raja, respectively, exhibited the greatest 1,1-diphenyl-2-picrylhydrazyl radical (DPPH)-scavenging activity (408.21 ± 5.37 μg TE/g sample) and metal chelating activity (93.68 ± 0.74%). The combined or potentiation effects of the moderate vitamin C, gallic acid, and mangiferin contents in both extracts may be responsible for the activities. The highest mangiferin content (31.72 ± 2.57 μg/g sample) in the mature-green M. caesia (Binjai) could be the major contributor to its highest FRAP activity (868.29 ± 2.71 μg TE/g sample). This paper reports apparently the first comparative study highlighting the antioxidant activities of these fruit fleshes.
    Matched MeSH terms: Antioxidants/chemistry
  8. Anarjan N, Tan CP, Nehdi IA, Ling TC
    Food Chem, 2012 Dec 1;135(3):1303-9.
    PMID: 22953858 DOI: 10.1016/j.foodchem.2012.05.091
    Astaxanthin colloidal particles were produced using solvent-diffusion technique in the presence of different food grade surface active compounds, namely, Polysorbate 20 (PS20), sodium caseinate (SC), gum Arabic (GA) and the optimum combination of them (OPT). Particle size and surface charge characteristics, rheological behaviour, chemical stability, colour, in vitro cellular uptake, in vitro antioxidant activity and residual solvent concentration of prepared colloidal particles were evaluated. The results indicated that in most cases the mixture of surface active compounds lead to production of colloidal particles with more desirable physicochemical and biological properties, as compared to using them individually. The optimum combination of PS20, SC and GA could produce the astaxanthin colloidal particles with small particle size, polydispersity index (PDI), conductivity and higher zeta potential, mobility, cellular uptake, colour intensity and in vitro antioxidant activity. In addition, all prepared astaxanthin colloidal particles had significantly (p<0.05) higher cellular uptake than pure astaxanthin powder.
    Matched MeSH terms: Antioxidants/chemistry*
  9. Naidu KR, Kumar KS, Arulselvan P, Reddy CB, Lasekan O
    Arch Pharm (Weinheim), 2012 Dec;345(12):957-63.
    PMID: 23015406 DOI: 10.1002/ardp.201200192
    A series of α-hydroxyphosphonates were synthesized from the reaction of aldehyde (1) with triethylphosphite (2) in the presence of oxone and evaluated for their antioxidant properties against lipid peroxidation, reduced glutathione, superoxide dismutase, and catalase. The majority of the compounds showed promising antioxidant activity. Diethyl anthracen-9-yl (hydroxy) methylphosphonate (3n) is the most potent and biologically active compound against free radicals.
    Matched MeSH terms: Antioxidants/chemistry
  10. Memon AA, Wahid H, Rosnina Y, Goh YM, Ebrahimi M, Nadia FM
    Anim. Reprod. Sci., 2012 Dec;136(1-2):55-60.
    PMID: 23182473 DOI: 10.1016/j.anireprosci.2012.10.020
    This study was conducted to determine the effect of antioxidants on standard semen parameters, lipid peroxidation and fertility of Boer goat semen after cryopreservation. Ejaculates from four bucks were collected, evaluated and pooled at 37°C. The pooled semen was diluted with Tris citric acid fructose for washing. Semen samples, which were diluted with a Tris-based extender containing the antioxidant ascorbic acid (8.5mg/ml), butylated hydroxytoluene (2mM), cysteine (5mM) and hypotaurine (10mM) and an extender without antioxidant supplementation were cooled to 4°C and frozen in 0.25 straws with programmable freezer and finally stored in liquid nitrogen. Data (10 replicates) were analyzed by one-way analysis of variance. Mean (±SEM) progressive motility was significantly higher in ascorbic acid than other supplement groups and control samples (P>0.05). Best values were observed in ascorbic acid followed by BHT, cysteine, and hypotaurine. Antioxidant supplementation in extender showed significant (P<0.05) better values than the control group for sperm membrane integrity, acrosome integrity and viability. The ability of antioxidants to reduce the lipid peroxidation (LPO) after freeze thawing was measured by the formation of malondialdehyde (MDA) using the thiobarbituric acid method. Results showed that addition of antioxidants significantly reduced the rate of LPO in comparison to control (P<0.05). Ascorbic acid exhibited better values (1.27±0.28), than butylated hydroxytoluene, cysteine and hypotaurine 1.32±0.42, 2.27±0.16 and 2.38±0.17 respectively, which are significantly better than control (3.52±0.54). Higher pregnancy rate was observed with ascorbic acid followed by butylated hydroxtolune, hypotaurine and cysteine. However, differences in the fertility rate were non-significant with hypotaurine, cysteine and control groups.
    Matched MeSH terms: Antioxidants/chemistry
  11. Salleh WM, Ahmad F, Yen KH, Sirat HM
    Nat Prod Commun, 2012 Dec;7(12):1659-62.
    PMID: 23413576
    This study was designed to investigate the antioxidant and antimicrobial activities of the essential oils from Piper officinarum C. DC. GC and GC/MS analysis of the leaf and stem oils showed forty one components, representing 85.6% and 93.0% of the oil, respectively. The most abundant components in the leaf oil were beta-caryophyllene (11.2%), alpha-pinene (9.3%), sabinene (7.6%), beta-selinene (5.3%) and limonene (4.6%), while beta-caryophyllene (10.9%), alpha-phellandrene (9.3%), linalool (6.9%), limonene (6.7%) and alpha-pinene (5.0%) were the main components of the stem oil. The antioxidant activities were determined by using complementary tests: namely beta-carotene-linoleic acid, DPPH radical scavenging and total phenolic assays. The stems oil showed weak activity (IC50 = 777.4 microg/mL) in the DPPH system, but showed moderate lipid peroxidation inhibition in the beta-carotene-linoleic acid system (88.9 +/- 0.35%) compared with BHT (95.5 +/- 0.30%). Both oils showed weak activity against P. aeruginosa and E. coli with M IC values of 250 microg/mL.
    Matched MeSH terms: Antioxidants/chemistry
  12. Manaharan T, Palanisamy UD, Ming CH
    Molecules, 2012;17(5):5915-23.
    PMID: 22609782 DOI: 10.3390/molecules17055915
    Preliminary investigations on 14 plant extracts (obtained by ethanolic and aqueous extraction) identified those having high antioxidant and a significant total phenolic content. Antihyperglycemic, α-amylase and α-glucosidase inhibition activities were also observed. A correlation between the antihyperglycemic activity, total phenolic content and antioxidant (DPPH scavenging) activity was established. To further substantiate these findings, the possibility of tannins binding non-specifically to enzymes and thus contributing to the antihyperglycemic activity was also investigated. Our study clearly indicated that the antihyperglycemic activity observed in the plant extracts was indeed not due to non-specific tannin absorption.
    Matched MeSH terms: Antioxidants/chemistry
  13. Alnajar ZA, Abdulla MA, Ali HM, Alshawsh MA, Hadi AH
    Molecules, 2012;17(3):3547-59.
    PMID: 22433579 DOI: 10.3390/molecules17033547
    Melastoma malabathricum (MM) is a well-known plant in Malaysian traditional medicine, locally known as senduduk. Its ethanol and aqueous extracts have been used in the present investigation to study the immunomodulatory role on human peripheral blood mononuclear cell (PBMC), and the DPPH, ABTS and FRAP free radical scavenging activities were also measured. Total flavonoids and total phenolic contents were assayed and the antibacterial effect was tested against four species of bacteria; two Gram-positive (Staphylococcus aureus and Streptococcus agalactiae) and two Gram-negative (Escherichia coli and Klebsilla pneumonia). The tests were carried out using the disc diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. Moreover, the acute toxicity was evaluated in vivo on the ethanol extract of MM to establish its safety when administered orally. In our results, both extracts of MM showed abilities to scavenge DPPH and ABTS free radicals, IC(50) values: (11.599 ± 0.84, 10.573 ± 0.58 µmol/L) and (62.657 ± 0.78, 63.939 ± 0.48 µmol/L) for ethanol and aqueous extracts respectively. Indeed the ethanol extract evidenced high phenolic content (384.33 ± 0.005 mg/g), flavonoids contents (85.8 ± 0.009 mg/g) and ferric reducing antioxidant power (33,590 ± 0.038 mmol/g), with high activity against S. aureus and S. agalactiae (11 ± 0.3 and 12 ± 0.6 mm inhibition zones). Likewise, the percentage of peripheral blood mononuclear cells (PBMC) viability was increased in response to MM, IC(50) values (1.781 ± 1.2 and 6.545 ± 0.93 µg/mL) for ethanol and aqueous extracts, respectively. In addition, our results showed that the MM extract is safe even at a high dose of 5,000 mg/kg and has no oral toxicity. These findings suggest the excellent medicinal bioactivity of MM and explain the popularity of this plant in the folk medicine as a remedy for different illnesses.
    Matched MeSH terms: Antioxidants/chemistry*
  14. Ibrahim MH, Jaafar HZ
    Int J Mol Sci, 2012;13(5):5290-306.
    PMID: 22754297 DOI: 10.3390/ijms13055290
    A randomized complete block design experiment was designed to characterize the relationship between production of total flavonoids and phenolics, anthocyanin, photosynthesis, maximum efficiency of photosystem II (Fv/Fm), electron transfer rate (Fm/Fo), phenyl alanine lyase activity (PAL) and antioxidant (DPPH) in Labisia pumila var. alata, under four levels of irradiance (225, 500, 625 and 900 μmol/m(2)/s) for 16 weeks. As irradiance levels increased from 225 to 900 μmol/m(2)/s, the production of plant secondary metabolites (total flavonoids, phenolics and antocyanin) was found to decrease steadily. Production of total flavonoids and phenolics reached their peaks under 225 followed by 500, 625 and 900 μmol/m(2)/s irradiances. Significant positive correlation of production of total phenolics, flavonoids and antocyanin content with Fv/Fm, Fm/Fo and photosynthesis indicated up-regulation of carbon-based secondary metabolites (CBSM) under reduced photoinhibition on the under low light levels condition. At the lowest irradiance levels, Labisia pumila extracts also exhibited a significantly higher antioxidant activity (DPPH) than under high irradiance. The improved antioxidative activity under low light levels might be due to high availability of total flavonoids, phenolics and anthocyanin content in the plant extract. It was also found that an increase in the production of CBSM was due to high PAL activity under low light, probably signifying more availability of phenylalanine (Phe) under this condition.
    Matched MeSH terms: Antioxidants/chemistry
  15. Ibrahim MH, Jaafar HZ, Rahmat A, Rahman ZA
    Int J Mol Sci, 2012;13(1):393-408.
    PMID: 22312260 DOI: 10.3390/ijms13010393
    A split plot 3 by 4 experiment was designed to characterize the relationship between production of gluthatione (GSH), oxidized gluthatione (GSSG), total flavonoid, anthocyanin, ascorbic acid and antioxidant activities (FRAP and DPPH) in three varieties of Labisia pumila Blume, namely the varieties alata, pumila and lanceolata, under four levels of nitrogen fertilization (0, 90, 180 and 270 kg N/ha) for 15 weeks. The treatment effects were solely contributed by nitrogen application; there was neither varietal nor interaction effects observed. As the nitrogen levels decreased from 270 to 0 kg N/ha, the production of GSH and GSSG, anthocyanin, total flavonoid and ascorbic acid increased steadily. At the highest nitrogen treatment level, L. pumila exhibited significantly lower antioxidant activities (DPPH and FRAP) than those exposed to limited nitrogen growing conditions. Significant positive correlation was obtained between antioxidant activities (DPPH and FRAP), total flavonoid, GSH, GSSG, anthocyanin and ascorbic acid suggesting that an increase in the antioxidative activities in L. pumila under low nitrogen fertilization could be attributed to higher contents of these compounds. From this observation, it could be concluded that in order to avoid negative effects on the quality of L. pumila, it is advisable to avoid excessive application of nitrogen fertilizer when cultivating the herb for its medicinal use.
    Matched MeSH terms: Antioxidants/chemistry*
  16. Chan KW, Khong NM, Iqbal S, Umar IM, Ismail M
    Int J Mol Sci, 2012;13(7):8987-97.
    PMID: 22942747 DOI: 10.3390/ijms13078987
    Sweet potato is known to be rich in healthful antioxidants, but the stability of its antioxidant properties under gastrointestinal pH is very much unknown. Hence, this study aimed to evaluate the changes in antioxidant properties (total contents of phenolics and flavonoids as well as antioxidant activity) of sweet potato flour (SPF) under simulated gastrointestinal pH conditions. It was found that the yield of SPF crude phenolic extract increased from 0.29 to 3.22 g/100 g SPF upon subjection to gastrointestinal pH conditions (p < 0.05). Also elevated significantly were the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of SPF (p < 0.05). In summary, the antioxidant properties of SPF were enhanced under gastrointestinal pH conditions, suggesting that SPF might possess a considerable amount of bound phenolic and other antioxidative compounds. The antioxidant properties of SPF are largely influenced by pH and thus might be enhanced during the in vivo digestive process.
    Matched MeSH terms: Antioxidants/chemistry*
  17. Hashim NM, Rahmani M, Ee GC, Sukari MA, Yahayu M, Amin MA, et al.
    Molecules, 2012;17(5):6071-82.
    PMID: 22614861 DOI: 10.3390/molecules17056071
    One of the most promising plants in biological screening test results of thirteen Artocarpus species was Artocarpus obtusus FM Jarrett and detailed phytochemical investigation of powdered dried bark of the plant has led to the isolation and identification of three xanthones; pyranocycloartobiloxanthone A (1), dihydroartoindonesianin C (2) and pyranocycloartobiloxanthone B (3). These compounds were screened for antioxidant, antimicrobial and tyrosinase inhibitory activities. Pyranocycloartobiloxanthone A (1) exhibited a strong free radical scavenger towards DPPH free radicals with IC50 value of 2 µg/mL with prominent discoloration observed in comparison with standard ascorbic acid, α-tocopherol and quercetin, The compound also exhibited antibacterial activity against methicillin resistant Staphylococcus aureus (ATCC3359) and Bacillus subtilis (clinically isolated) with inhibition zone of 20 and 12 mm, respectively. However the other two xanthones were found to be inactive. For the tyrosinase inhibitory activity, again compound (1) displayed strong activity comparable with the standard kojic acid.
    Matched MeSH terms: Antioxidants/chemistry
  18. Chan KW, Khong NM, Iqbal S, Ismail M
    Int J Mol Sci, 2012;13(6):7496-507.
    PMID: 22837707 DOI: 10.3390/ijms13067496
    The present study was conducted to evaluate the antioxidant properties of wheat and rice flours under simulated gastrointestinal pH condition. After subjecting the wheat and rice flour slurries to simulated gastrointestinal pH condition, both slurries were centrifuged to obtain the crude phenolic extracts for further analyses. Extraction yield, total contents of phenolic and flavonoids were determined as such (untreated) and under simulated gastrointestinal pH condition (treated). 1,1-diphenyl-2-picrylhydrazyl radical (DPPH(•)) scavenging activity, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radical cation (ABTS(•+)) scavenging activity, ferric reducing antioxidant power (FRAP), beta-carotene bleaching (BCB) and iron chelating activity assays were employed for the determination of antioxidant activity of the tested samples. In almost all of the assays performed, significant improvements in antioxidant properties (p < 0.05) were observed in both flours after treatment, suggesting that wheat and rice flours contain considerably heavy amounts of bound phenolics, and that their antioxidant properties might be improved under gastrointestinal digestive conditions.
    Matched MeSH terms: Antioxidants/chemistry*
  19. Lim SM, Yim HS
    Int J Med Mushrooms, 2012;14(6):593-602.
    PMID: 23510253
    A central composite design of response surface methodology (RSM) was employed to optimize the extraction time (X1: 266.4-393.6 min) and temperature (X2: 42.9-57.1°C) of Pleurotus ostreatus aqueous extract with high antioxidant activities, namely DPPH radical-scavenging activity, ABTS radical cation inhibition, and ferric reducing/antioxidant power, as well as total phenolic content (TPC). Results showed that the data were adequately fitted into four second-order polynomial models developed by RSM. The extraction time and temperature were found to have significant quadratic effects on antioxidant activities and TPC. The optimal extraction time and temperature were 282.3 min and 42.9°C (DPPH), 393.6 min and 42.9°C (ABTS), 340.4 min and 49.8°C (FRAP), and 347.6 min, 49.7°C (TPC), with corresponding yields of 53.32%, 73.20%, 37.14 mM Fe2+ equivalents/100 g, and 826.33 mg gallic acid equivalents/100 g, respectively. These experimental data were close to their predicted values. The establishment of such a model provides a good experimental basis for employing RSM to optimize the extraction time and temperature for high antioxidant activities from P. ostreatus.
    Matched MeSH terms: Antioxidants/chemistry
  20. Imam MU, Musa SN, Azmi NH, Ismail M
    Int J Mol Sci, 2012;13(10):12952-69.
    PMID: 23202932 DOI: 10.3390/ijms131012952
    Oxidative stress is implicated in the pathogenesis of diabetic complications, and can be increased by diet like white rice (WR). Though brown rice (BR) and germinated brown rice (GBR) have high antioxidant potentials as a result of their bioactive compounds, reports of their effects on oxidative stress-related conditions such as type 2 diabetes are lacking. We hypothesized therefore that if BR and GBR were to improve antioxidant status, they would be better for rice consuming populations instead of the commonly consumed WR that is known to promote oxidative stress. This will then provide further reasons why less consumption of WR should be encouraged. We studied the effects of GBR on antioxidant status in type 2 diabetic rats, induced using a high-fat diet and streptozotocin injection, and also evaluated the effects of WR, BR and GBR on catalase and superoxide dismutase genes. As dietary components, BR and GBR improved glycemia and kidney hydroxyl radical scavenging activities, and prevented the deterioration of total antioxidant status in type 2 diabetic rats. Similarly, GBR preserved liver enzymes, as well as serum creatinine. There seem to be evidence that upregulation of superoxide dismutase gene may likely be an underlying mechanism for antioxidant effects of BR and GBR. Our results provide insight into the effects of different rice types on antioxidant status in type 2 diabetes. The results also suggest that WR consumption, contrary to BR and GBR, may worsen antioxidant status that may lead to more damage by free radicals. From the data so far, the antioxidant effects of BR and GBR are worth studying further especially on a long term to determine their effects on development of oxidative stress-related problems, which WR consumption predisposes to.
    Matched MeSH terms: Antioxidants/chemistry
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