Displaying publications 1 - 20 of 58 in total

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  1. Wong, B.Y., Tan, C.P., Ho, C.W.
    MyJurnal
    The objective of this study was to evaluate the effects of solid-to-solvent ratio (1:5. 1:10, 1:15 and 1:20) on the extraction of phenolic compounds (TPC and TFC) and antioxidant capacity (ABTS and DPPH radical scavenging capacity) of P. niruri. Solid-to-solvent ratio showed a significant effect for both phenolic compounds (TPC and TFC) and antioxidant capacity (ABTS and DPPH radical scavenging capacity) with 1:20 was the condition for extracting the highest of phenolic compounds (TPC and TFC) with a value of 5788.7 mg GAE/100 g DW and 1906.5 mg CE/100 g DW, respectively and exhibited high antioxidant capacities (ABTS and DPPH radical scavenging capacities) with a value of 0.820 mM and 1.598 mM, respectively among the four levels studied. TPC was positively and significantly correlated with ABTS and DPPH (r=0.999 and r=0.999) under the effects of solid-to-solvent ratio as compared to TFC, positively and strongly correlated (r=0.865 and r=0.868) with ABTS and DPPH.
    Matched MeSH terms: Sulfonic Acids
  2. Emmclan LSH, Zakaria MH, Ramaiya SD, Natrah I, Bujang JS
    PeerJ, 2022;10:e12821.
    PMID: 35111414 DOI: 10.7717/peerj.12821
    BACKGROUND: Coastal land development has deteriorated the habitat and water quality for seagrass growth and causes the proliferation of opportunist macroalgae that can potentially affect them physically and biochemically. The present study investigates the morphological and biochemical responses of seagrass from the Hydrocharitaceae family under the macroalgal bloom of Ulva reticulata, induced by land reclamation activities for constructing artificial islands.

    METHODS: Five seagrass species, Enhalus acoroides, Thalassia hemprichii, Halophila ovalis, Halophila major, and Halophila spinulosa were collected at an Ulva reticulata-colonized site (MA) shoal and a non-Ulva reticulata-colonized site (MC) shoal at Sungai Pulai estuary, Johor, Malaysia. Morphometry of shoots comprising leaf length (LL), leaf width (LW), leaf sheath length (LSL), leaflet length (LTL), leaflet width (LTW), petiole length (PL), space between intra-marginal veins (IV) of leaf, cross vein angle (CVA) of leaf, number of the cross vein (NOC), number of the leaf (NOL) and number of the leaflet (NOLT) were measured on fresh seagrass specimens. Moreover, in-situ water quality and water nutrient content were also recorded. Seagrass extracts in methanol were assessed for total phenolic content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid radical cation scavenging activity (ABTS), and ferric reducing antioxidant power (FRAP).

    RESULTS: Seagrasses in the U. reticulata-colonized site (MA) had significantly higher (t-test, p < 0.05) leaf dimensions compared to those at the non-U. reticulata colonized site (MC). Simple broad-leaved seagrass of H. major and H. ovalis were highly sensitive to the colonization of U. reticulata, which resulted in higher morphometric variation (t-test, p < 0.05) including LL, PL, LW, and IV. Concerning the biochemical properties, all the seagrasses at MA recorded significantly higher (t-test, p < 0.05) TPC, TFC, and ABTS and lower DPPH and FRAP activities compared to those at MC. Hydrocharitaceae seagrass experience positive changes in leaf morphology features and metabolite contents when shaded by U. reticulata. Researching the synergistic effect of anthropogenic nutrient loads on the interaction between seagrasses and macroalgae can provide valuable information to decrease the negative effect of macroalgae blooms on seagrasses in the tropical meadow.

    Matched MeSH terms: Sulfonic Acids
  3. Nizar SA, Mohd Suah FB
    J Fluoresc, 2016 Jul;26(4):1167-71.
    PMID: 27286697 DOI: 10.1007/s10895-016-1845-9
    The effect of room temperature ionic liquid (RTIL) on the formation of the fluorescence ternary complex oxalate-sodium morin-5-sulfonate (NaMSA)-Aluminium(III) has been studied. In weakly acidic medium and in the presence of RTIL, 1-Butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6), total complex formation is achieved as compared with the formation of the binary complex of NaMSA-Aluminium(III). The fluorescence characteristics of the system allowed the establishment of a very sensitive method for the spectrofluorimetric determination of oxalate ion. The ternary complex formed its highest fluorescence signal at 513 nm and excitation at 420 nm. In these conditions, the method produces a detection limit of 0.57 ng mL(-1). The procedure has been satisfactorily applied to the determination of oxalate ion in a vegetal tissue (spinach leaves).
    Matched MeSH terms: Sulfonic Acids/chemistry*
  4. Tay BY
    Int J Cosmet Sci, 2013 Feb;35(1):57-63.
    PMID: 22994145 DOI: 10.1111/ics.12004
    A simple and rapid gas chromatography (GC) method with flame ionization detector was developed for detection of isopropyl para-toluenesulphonate (IPTS) in palm-based isopropyl palmitate (IPP) and isopropyl myristate (IPM). The method involved spiking the IPP/IPM samples with IPTS and directly injecting the spiked samples into GC without undergoing clean-up steps. The calibration curves for IPTS showed good linearity with coefficient correlation of 0.9999 for six-point calibration from 0.5 to 50 μg mL(-1) and 0.9996 for six-point calibration from 0.5 to 200 μg mL(-1) . IPTS recoveries from IPP were 98.6-103.5% with relative standard deviation (RSD) of 0.40-2.80%, whereas recoveries from IPM were 97.0-107.2% with RSD of 0.42-4.21%. The identity of IPTS recovered from the isopropyl esters was confirmed by a GC-mass spectrometer detector. The method was successfully applied to the analyses of IPTS in commercial samples. It was found that there were IPTS in the range of 34.8-1303.0 μg g(-1) in the palm-based esters for some of the samples analysed.
    Matched MeSH terms: Sulfonic Acids/analysis*
  5. Yusof NZ, Azizul Hasan ZA, Abd Maurad Z, Idris Z
    Cutan Ocul Toxicol, 2018 Jun;37(2):103-111.
    PMID: 28693384 DOI: 10.1080/15569527.2017.1352595
    AIM: To evaluate eye irritation potential of palm-based methyl ester sulphonates (MES) of different chain lengths; C12, C14, C16, C16:18.

    METHODS: The Bovine Corneal Opacity and Permeability test method (BCOP), OECD Test Guideline 437, was used as an initial step to study the inducing effect of palm-based MES on irreversible eye damage. The second assessment involved the use of reconstructed human corneal-like epithelium test method, OECD Test Guideline 492 using SkinEthic™ Human Corneal Epithelium to study the potential effect of palm-based MES on eye irritancy. The palm-based MES were prepared in 10% solution (w/v) in deionized water and tested as a liquid and surfactant test substances whereby both test conducted according to the liquid/surfactant treatment protocol.

    RESULTS: The preliminary BCOP results showed that palm-based MES; C12, C14, C16, C16:18 were not classified as severe eye irritants test substances with in vitro irritancy score between 3 and the threshold level of 55. The second evaluation using SkinEthic™ HCE model showed that palm-based MES; C12, C14, C16, C16:18 and three commercial samples were potentially irritants to the eyes with mean tissue viability ≤ 60% and classified as Category 2 according to United Nations Globally Harmonized System of Classification and Labelling of Chemicals. However, there are some limitations of the proposed ocular irritation classification of palm-based MES due to insolubility of long chain MES in 10% solution (w/v) in deionized water.

    CONCLUSION: Therefore, future studies to clarify the eye irritation potential of the palm-based MES will be needed, and could include; methods to improve the test substance solubility, use of test protocol for solids, and/or inclusion of a benchmark anionic surfactant, such as sodium dodecyl sulphate within the study design.

    Matched MeSH terms: Sulfonic Acids/classification; Sulfonic Acids/toxicity*
  6. Yim HS, Chye FY, Rao V, Low JY, Matanjun P, How SE, et al.
    J Food Sci Technol, 2013 Apr;50(2):275-83.
    PMID: 24425917 DOI: 10.1007/s13197-011-0349-5
    Central composite design of response surface methodology (RSM) was employed to optimize the extraction time (X 1 : 99.5-290.5 min) and temperature (X 2 : 30.1-54.9 °C) of Schizophyllum commune aqueous extract with high antioxidant activities and total phenolic content (TPC). Results indicated that the data were adequately fitted into four second-order polynomial models. The extraction time and temperature were found to have significant linear, quadratic and interaction effects on antioxidant activities and TPC. The optimal extraction time and temperature were: 290.5 min and 35.7 °C (DPPH(•) scavenging ability); 180.7 min and 41.7 °C (ABTS(•+) inhibition ability); 185.2 min and 42.4 °C (ferric reducing antioxidant power, FRAP); 290.5 min and 40.3 °C (TPC). These optimum conditions yielded 85.10%; 94.31%; 0.74 mM Fe(2+) equivalent/100 g; 635.76 mg gallic acid equivalent/100 g, respectively. The yields of antioxidant activities and TPC obtained experimentally were close to its predicted values. The establishment of such model provides a good experimental basis employing RSM for optimizing the extraction time and temperature on antioxidants from S. commune aqueous extract.
    Matched MeSH terms: Sulfonic Acids
  7. 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: Sulfonic Acids
  8. Abdullah SA, Jamil S, Basar N, Abdul Lathiff SM, Mohd Arriffin N
    Nat Prod Res, 2017 May;31(10):1113-1120.
    PMID: 27564208 DOI: 10.1080/14786419.2016.1222387
    A new dihydrochalcone, 2',4'-dihydroxy-3,4-(2″,2″-dimethylchromeno)-3'-prenyldihydrochalcone (1) together with 4-hydroxyonchocarpin (2), isobavachalcone (3), 4',5-dihydroxy-6,7-(2,2-dimethylpyrano)-2'-methoxy-8-γ,γ-dimethylallyflavone (4), artocarpin (5) and cycloheterophyllin (6) were successfully isolated from the leaves and heartwoods of Artocarpus lowii King (Moraceae). The structures of these compounds were fully characterised using spectroscopic methods and by direct comparison with published data. These compounds were tested for their antioxidant and tyrosinase inhibitory activities. Compound (1) displayed moderate antioxidant activity towards DPPH and tyrosinase inhibitory activities with SC50 value of 223.8 μM and IC50 value of 722.5 μM, respectively. Among the isolated compounds, cycloheterophyllin (6) showed the most potential antioxidant activity with SC50 value of 320.0 and 102.8 μM for ABTS and DPPH radicals scavenging activities, respectively, and also exhibited highest FRAP equivalent value of 4.7 ± 0.09 mM. Compound (6) showed tyrosinase inhibitory activity with the IC50 value of 104.6 μM.
    Matched MeSH terms: Sulfonic Acids
  9. Woo, P.F., Yim, H.S., Khoo, H.E., Sia, C.M., Ang, Y.K.
    MyJurnal
    This study investigated the effects of different percentages of ethanol (0 - 100%), extraction times (1 - 5 h) and temperatures (25 - 60°C) on total phenolic content (TPC) and antioxidant activity (AA) of sapodilla pulp and peel. TPC was determined by Folin-Ciocalteu reagent method, while AA was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, 2,2-azino-bis-(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay, ferric reducing antioxidant power (FRAP) assay and β-carotene bleaching (BCB) assay. Based on the optimal extraction conditions used, sapodilla pulp extract had TPC of 3.89 mg GAE/g, 63.20% of DPPH scavenging activity, 4.30% of ABTS scavenging activity, 19.17% of BCB activity, and FRAP value of 15.24 mg TE/g; while its peel extract had TPC of 9.23 mg GAE/g, 92.95% of DPPH scavenging activity, 5.36% of ABTS scavenging activity, 8.14% of BCB activity, and 27.85 mg TE/g (FRAP value). Using the optimal extraction conditions for sapodilla pulp (40% ethanol as extraction solvent that extracted at 60°C for 4 h) and sapodilla peel (80% ethanol and 2 h extraction time at 40°C), highest antioxidants can be extracted from the pulp and peel.
    Matched MeSH terms: Sulfonic Acids
  10. Salar U, Khan KM, Jabeen A, Faheem A, Fakhri MI, Saad SM, et al.
    Bioorg Chem, 2016 12;69:37-47.
    PMID: 27669119 DOI: 10.1016/j.bioorg.2016.09.006
    Coumarin sulfonates 4-43 were synthesized by reacting 3-hydroxy coumarin 1, 4-hydroxy coumarin 2and6-hydroxy coumarin 3 with different substituted sulfonyl chlorides and subjected to evaluate for their in vitro immunomodulatory potential. The compounds were investigated for their effect on oxidative burst activity of zymosan stimulated whole blood phagocytes using a luminol enhanced chemiluminescence technique. Ibuprofen was used as standard drug (IC50=54.2±9.2μM). Eleven compounds 6 (IC50=46.60±14.6μM), 8 (IC50=11.50±6.5μM), 15 (IC50=21.40±12.2μM), 19 (IC50=5.75±0.86μM), 22 (IC50=10.27±1.06μM), 23 (IC50=33.09±5.61μM), 24 (IC50=4.93±0.58μM), 25 (IC50=21.96±14.74μM), 29 (IC50=12.47±9.2μM), 35 (IC50=20.20±13.4μM) and 37 (IC50=14.47±5.02μM) out of forty demonstrated their potential suppressive effect on production of reactive oxygen species (ROS) as compared to ibuprofen. All the synthetic derivatives 4-43 were characterized by different available spectroscopic techniques such as 1H NMR, 13C NMR, EIMS and HRMS. CHN analysis was also performed.
    Matched MeSH terms: Sulfonic Acids/chemical synthesis; Sulfonic Acids/pharmacology*; Sulfonic Acids/chemistry
  11. Bimakr, M., Rahman, R.A., Saleena Taip, F., Adzahan, N.M., Islam Sarker, Z., Ganjloo, A
    MyJurnal
    Ultrasound-assisted extraction (UAE) was applied for the extraction of bioactive valuable compounds from winter melon (Benincasa hispida) seeds. Effects of amplitude (25-75%), temperature (40-60°C) and sonication time (20-60 min) on crude extraction yield (CEY) and radical scavenging activities (RSA, % inhibition of DPPH˙ and ABTS˙+ free radicals) of extracts were determined using complete randomised design (CRD). The results showed that the CEY and RSA of extracts significantly affected by independent variables. The maximum value of CEY (97.14±0.36 mgg-1), scavenging of DPPH˙ radicals (32.12 ± 0.38%) and scavenging of ABTS˙+ radicals (40.52±0.73%) were obtained at the combined treatment conditions of 75%, 55°C and 40 min. The UAE results obtained were compared with those achieved by using conventional Soxhlet extraction (CSE) method. It was found UAE allowed extraction at lower temperature and the extracts obtained posses higher quality compare with CSE. UAE is a promising environment friendly technique for the extraction of bioactive compounds from winter melon (Benincasa hispida) seeds.
    Matched MeSH terms: Sulfonic Acids
  12. Thoo, Y.Y., Ng, S.Y., Khoo, M.Z., Wan Aida, W.M., Ho, C.W.
    MyJurnal
    The effects of ethanol concentration (0-100%, v/v), extraction time (60-300 min) and extraction temperature (25-65°C) on the extraction of phenolic antioxidants from Andrographis paniculata was evaluated using single-factor experiments. The following complementary assays were used to screen the antioxidant properties of the crude extracts: total phenolic content (TPC), total flavonoid content (TFC), condensed tannin content (CTC), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical-scavenging capacity and 2,2’-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity. The extraction conditions chosen had significant effects (p < 0.05) on the extraction of phenolic compounds and antioxidant capacity. The optimal conditions were 60% ethanol for 60 min at 65oC for phenolic compounds and at 25oC for antioxidant capacity. Strong negative significant (p < 0.05) correlations were observed between the phenolic compounds (TPC, TFC and CTC) and antioxidant capacity comprising ABTS (-0.924, -0.909, -0.887, respectively) and DPPH radical-scavenging capacities (-0.992, -0.938, -0.928, respectively) were determined under the influence of extraction temperature.
    Matched MeSH terms: Sulfonic Acids
  13. Zuhair, R.A., Aminah, A., Sahilah, A.M., Eqbal, D.
    MyJurnal
    Papaya (Carica papaya L. cv. Hongkong) is an economically important fruit crop grown in Malaysia. During its ripening stages, (C. papaya L.) exhibits different physicochemical properties, antioxidant capacities, and sensory quality results. The objective of this study was to elucidate in detail the antioxidant capacity of C. papaya as determined by total phenol content (TPC), total flavonoid content (TFC), ferric reducing antioxidant power (FRAP),2,2-diphenyl-1-picrylhydrazyl (DPPH) and scavenging systemand (ABTS). The study also aimed to study physicochemical changes of papaya fruits based on measured pH, titratable acidity (TA), total soluble solids (TSS), moisture and fruit color at five different stages of ripening. The fruits were harvested at five different, stages RS1, RS2, RS3, RS4, and RS5 corresponding to 12, 14, 16, 18, and 20 weeks after anthesis, respectively. Significant differences were found at different stages of ripening. The pH of the fruit decreased significantly (P < 0.05), whereas TA, moisture, and TSS increased significantly (P < 0.05) during the ripening process. The redness (a*) and yellowness (b*) values of fruit color both increased significantly (P < 0.05), whereas
    lightness (L*) varied. The total phenol content TPC, TFC, FRAP, DPPH and ABTS values increased significantly (P < 0.05) with the ripening process. Sensory evaluation based on the color, sweetness, sourness, flavor, and overall acceptance for the last three maturity stages was also performed. RS5 had a better score than RS3 or RS4. The results showed the important role of the ripening stage in increasing the antioxidant content of papaya fruits.
    Matched MeSH terms: Sulfonic Acids
  14. Mohammad NA, Abang Zaidel DN, Muhamad II, Abdul Hamid M, Yaakob H, Mohd Jusoh YM
    Heliyon, 2019 Oct;5(10):e02571.
    PMID: 31667409 DOI: 10.1016/j.heliyon.2019.e02571
    Total phenolic content (TPC) and antioxidant properties of xanthone extract from mangosteen pericarp via microwave-assisted extraction (MAE) method was optimized by response surface methodology (RSM). The MAE extraction conditions to obtain optimum antioxidant-rich xanthone extract were at 2.24 min of irradiation time, 25 mL/g of solvent-to-solid ratio and 71% of ethanol concentration. The predicted results for four responses were as follows; 320.31 mg gallic acid equivalent/g extract, 83.63% and 93.77% inhibition (DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-Azino-bis-3-ethylbenzthiazoline-6-sulfonic acid) assays), and 144.56 mg Trolox equivalent/g extract (FRAP, Ferric reducing antioxidant power). The predicted and actual values were statistically insignificant (P > 0.05). Therefore, these results confirmed that the examined model was acceptable and relevant. MAE led to a slightly similar antioxidant capacity and a higher extraction of α-mangostin, a major xanthone of mangosteen pericarp as compared to water bath-maceration technique.
    Matched MeSH terms: Sulfonic Acids
  15. Abu F, Mat Taib CN, Mohd Moklas MA, Mohd Akhir S
    PMID: 28761496 DOI: 10.1155/2017/2907219
    Antioxidant properties of crude extract, partition extract, and fermented medium from Dendrobium sabin (DS) flower were investigated. The oven-dried DS flower was extracted using 100% methanol (w/v), 100% ethanol (w/v), and 100% water (w/v). The 100% methanolic crude extract showed the highest total phenolic content (40.33 ± mg GAE/g extract) and the best antioxidant properties as shown by DPPH, ABTS, and FRAP assays. A correlation relationship between antioxidant activity and total phenolic content showed that phenolic compounds were the dominant antioxidant components in this flower extract. The microbial fermentation on DS flower medium showed a potential in increasing the phenolic content and DPPH scavenging activity. The TPC of final fermented medium showed approximately 18% increment, while the DPPH of fermented medium increased significantly to approximately 80% at the end of the fermentation. Dendrobium sabin (DS) flower showed very good potential properties of antioxidant in crude extract and partition extract as well as better antioxidant activity in the flower fermented medium.
    Matched MeSH terms: Sulfonic Acids
  16. Ho SK, Tan CP, Thoo YY, Abas F, Ho CW
    Molecules, 2014 Aug 19;19(8):12640-59.
    PMID: 25153876 DOI: 10.3390/molecules190812640
    Ultrasound-assisted extraction (UAE) with ethanol was used to extract the compounds responsible for the antioxidant activities of Misai Kucing (Orthosiphon stamineus). Response surface methodology (RSM) was used to optimize four independent variables: ethanol concentration (%), amplitude (%), duty cycle (W/s) and extraction time (min). Antioxidant compounds were determined by total phenolic content and total flavonoid content to be 1.4 g gallic acid equivalent/100 g DW and 45 g catechin equivalent/100 g DW, respectively. Antioxidant activities were evaluated using the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) radical scavenging capacity assay and the 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging capacity assay to be 1,961.3 and 2,423.3 µmol Trolox Equivalent Antioxidant Capacity (TEAC)/100 g DW, respectively. Based on the optimal conditions, experimental values were reported to be close to the predicted value by RSM modeling (p>0.05), indicating the suitability of UAE for extracting the antioxidants of Misai Kucing. Rosmarinic acid, kaempferol-rutinoside and sinesetine were identified by high performance liquid chromatography-mass spectrometry.
    Matched MeSH terms: Sulfonic Acids/chemistry
  17. Wong YS, Sia CM, Khoo HE, Ang YK, Chang SK, Chang SK, et al.
    Acta Sci Pol Technol Aliment, 2014 Jul-Sep;13(3):257-65.
    PMID: 24887941
    As a by-product of tropical fruit juice industry, passion fruit peel is a valuable functional food. It is rich in antioxidants. To determine its potential antioxidant properties of passion fruit peel, this study aimed to evaluate the effect of extraction conditions on total phenolic content and antioxidant activity.
    Matched MeSH terms: Sulfonic Acids/analysis
  18. Kumar CS, Loh WS, Ooi CW, Quah CK, Fun HK
    Molecules, 2013 Sep 26;18(10):11996-2011.
    PMID: 24077177 DOI: 10.3390/molecules181011996
    A series of six novel heterocyclic chalcone analogues 4(a-f) has been synthesized by condensing 2-acetyl-5-chlorothiophene with benzaldehyde derivatives in methanol at room temperature using a catalytic amount of sodium hydroxide. The newly synthesized compounds are characterized by IR, mass spectra, elemental analysis and melting point. Subsequently; the structures of these compounds were determined using single crystal X-ray diffraction. All the synthesized compounds were screened for their antioxidant potential by employing various in vitro models such as DPPH free radical scavenging assay, ABTS radical scavenging assay, ferric reducing antioxidant power and cupric ion reducing antioxidant capacity. Results reflect the structural impact on the antioxidant ability of the compounds. The IC₀ values illustrate the mild to good antioxidant activities of the reported compounds. Among them, 4f with a p-methoxy substituent was found to be more potent as antioxidant agent.
    Matched MeSH terms: Sulfonic Acids/chemistry
  19. Awang M, Seng GM
    ChemSusChem, 2008;1(3):210-4.
    PMID: 18605208 DOI: 10.1002/cssc.200700083
    The cost of chemicals prohibits many technically feasible enhanced oil recovery methods to be applied in oil fields. It is shown that by-products from oil palm processing can be a source of valuable chemicals. Analysis of the pyrolysis oil from oil palm shells, a by-product of the palm oil industry, reveals a complex mixture of mainly phenolic compounds, carboxylic acids, and aldehydes. The phenolic compounds were extracted from the pyrolysis oil by liquid-liquid extraction using alkali and an organic solvent and analyzed, indicating the presence of over 93% phenols and phenolic compounds. Simultaneous sulfonation and alkylation of the pyrolysis oil was carried out to produce surfactants for application in oil fields. The lowest measured surface tension and critical micelle concentration was 30.2 mNm(-1) and 0.22 wt%, respectively. Displacement tests showed that 7-14% of the original oil in place was recovered by using a combination of surfactants and xanthan (polymer) as additives.
    Matched MeSH terms: Sulfonic Acids/chemistry
  20. Danov KD, Stanimirova RD, Kralchevsky PA, Basheva ES, Ivanova VI, Petkov JT
    J Colloid Interface Sci, 2015 Nov 1;457:307-18.
    PMID: 26196714 DOI: 10.1016/j.jcis.2015.07.020
    The interest to sulfonated methyl esters of fatty acids (SME) has been growing during the last decade, because these surfactants are considered as an environmentally friendly and renewable alternative of the linear alkyl-benzene sulfonates (LAS). Here, we present a quantitative study on the properties of aqueous SME solutions, and especially on their surface tension isotherms, critical micelle concentration (CMC) and its dependence on the concentration of added NaCl. It is demonstrated that the CMC of an ionic surfactant determined by electrical conductivity is insensitive to the presence of a small nonionic admixture, so that the CMC values determined by conductivity represent the CMC of the pure surfactant. Using SME as an example, we have demonstrated the application of a new and powerful method for determining the physicochemical parameters of the pure ionic surfactant by theoretical data analysis ("computer purification") if the used surfactant sample contains nonionic admixtures, which are present as a rule. This method involves fits of the experimental data for surface tension and conductivity by a physicochemical model based on a system of mass-balance, chemical-equilibrium and electric-double-layer equations, which allows us to determine the adsorption and micellization parameters of C12-, C14-, C16- and C18-SME, as well the fraction of nonionic admixtures (if any). Having determined these parameters, we can further predict the interfacial and micellization properties of the surfactant solutions, such as surface tension, adsorption, degree of counterion binding, and surface electric potential at every surfactant, salt and co-surfactant concentrations.
    Matched MeSH terms: Sulfonic Acids/chemistry*
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