Displaying publications 41 - 60 of 637 in total

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  1. Khaidzir S, Masri AN, Ruslan MSH, Abdul Mutalib MI
    ACS Omega, 2021 Apr 13;6(14):9629-9637.
    PMID: 33869943 DOI: 10.1021/acsomega.1c00189
    In this study, piperidinium-based ionic liquids (IL) containing trifluoromethanesulfonate, phenolate, and dicyanamide anions were synthesized. Using the ILs, extraction of naphthenic acid from highly acidic oil with a total acid number (TAN) of 1.44 was studied. Two agitation techniques have been implemented for the extraction process, which were mechanical stirring and ultrasonic-assisted irradiation. 1-Butyl-1-methylpiperidinium phenolate [BMPi][Phe] showed the best potential in extracting naphthenic acid from oil, with complete removal of naphthenic acid with IL-to-oil ratios of 0.010 and 0.0025 for the mechanical stirring method and the ultrasonic-assisted method, respectively. Ultrasonic-assisted extraction process shows very good potential in enhancing the extraction efficiency of naphthenic acid. Optimization and study on the effects of ultrasonic parameters, namely, IL-to-oil ratio, ultrasonic amplitude, and time, were studied through response surface methodology (RSM). Using [BMPi][Phe], the optimum conditions obtained are IL-to-oil ratio of 0.03, 53.91% of amplitude, and 4.29 min of extraction time. Under these optimum conditions, 100% removal of naphthenic acid was achieved.
    Matched MeSH terms: Phenols
  2. Wong PL, Ramli NS, Tan CP, Azlan A, Abas F
    Phytochem Anal, 2021 Sep;32(5):685-697.
    PMID: 33295100 DOI: 10.1002/pca.3015
    INTRODUCTION: Ardisia elliptica Thunb. (Primulaceae) is a medicinal herb that is traditionally used for the treatment of fever, diarrhoea, measles and herpes. However, there is limited information regarding the correlation of its phytoconstituents with the bioactivity. Optimisation of solvent extraction is vital for maximising retention of bioactive molecules.

    OBJECTIVE: This study investigated the metabolite variations in A. elliptica leaves and the correlation with antioxidant activities.

    METHODOLOGY: Total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) radicals scavenging assays were performed on A. elliptica leaves extracted with four different ethanol ratios (0%, 50%, 70% and absolute ethanol). The correlation of metabolites with antioxidant activities was evaluated using a nuclear magnetic resonance (NMR)-based metabolomics approach.

    RESULTS: The results showed that the 50% and 70% ethanolic extracts retained the highest TPC, and the 70% ethanolic extract was the most active, exhibiting half maximal inhibitory concentration (IC50 ) values of 10.18 ± 0.83 and 43.05 ± 1.69 μg/mL, respectively, in both radical scavenging assays. A total of 46 metabolites were tentatively identified, including flavonoids, benzoquinones, triterpenes and phenolic derivatives. The 50% and 70% ethanolic extracts showed similarities in metabolites content and were well discriminated from water and absolute ethanol extracts in a principal component analysis (PCA) model. Moreover, 31 metabolites were found to contribute significantly to the differentiation and antioxidant activity.

    CONCLUSION: This study provides information on bioactive compounds in A. elliptica leaves, which is promising as a functional ingredient for food production or for the development of phytomedicinal products.

    Matched MeSH terms: Phenols
  3. Olalere OA, Gan CY, Akintomiwa OE, Adeyi O, Adeyi A
    Phytochem Anal, 2021 Sep;32(5):850-858.
    PMID: 33583076 DOI: 10.1002/pca.3030
    INTRODUCTION: The quality characteristics and stability of phenolic by-products from Cola nitida wastes are critical factors for drug formulation and food nutraceutical applications.

    OBJECTIVES: In this study, the effect of electromagnetic-based microwave-reflux extraction on the total phenolic content, antioxidant capacity, morphological characteristics, physisorption and chromatographic phenolic profiles were successfully investigated. These physicochemical analyses are often employed in the standardisation of dried herbal and food nutraceutical products.

    MATERIAL AND METHODS: In this study, the electromagnetic-based extraction process was optimised using the Box-Behnken design. The oleoresin bio-products were subsequently characterised to determine the total phenolic content, morphological and microstructural degradation. These analyses were conducted to elucidate the effect of the microwave heating on the C. nitida pod powder.

    RESULTS: From the predicted response, the optimal percentage yield was achieved at 26.20% under 5.39 min of irradiation time, 440 W microwave power and oven temperature of 55°C. Moreover, the rapid estimation of the phenolic content and antioxidant capacity were recorded at 124.84 ± 0.064 mg gallic acid equivalent (GAE)/g dry weight (d.w.) and 6.93 ± 0.34 μg/mL, respectively. The physicochemical characterisation results from the Fourier-transform infrared spectroscopy, field emission scanning electron microscopy and physisorption analyses showed remarkable changes in the micro-surface area (13.66%) characteristics.

    CONCLUSION: The recorded optimal conditions established a basis for future scale-up of microwave extraction parameters with a potential for maximum yield. The physiochemical characterisation revealed the functional characteristics of C. nitida and their tolerance to microwave heating.

    Matched MeSH terms: Phenols
  4. Kong, K.W., Emmy, H.K.I., Azizah, O., Amin, I., Tan, C.P.
    MyJurnal
    Lycopene and total phenolics of pink guava puree industry by-products (refiner, siever and decanter)
    were evaluated after steam blanching at selected temperatures and times. Lycopene content was in the order of decanter > siever > refiner (7.3, 6.3 and 1.5 mg/100 g, respectively), and the content of total phenolics was in the order of refiner > siever > decanter (4434.1, 2881.3 and 1529.3 mg GAE/100 g, respectively). Regression coefficients for temperatures (x1) and times (x2) from multiple linear regression models of siever and decanter showed significant (p
    Matched MeSH terms: Phenols
  5. Nor Qhairul Izzreen, M.N., Mohd Fadzelly, A.B.
    MyJurnal
    This study was conducted to determine the total phenolic (TPC) and total flavonoid content (TFC) as well as the antioxidant activity of 50% ethanolic extracts from different parts of Camellia sinensis (shoot, young and matured leaves). Comparison was also made between black (fermented) and green (unfermented) tea. For green tea, the results showed that the shoot contained significantly higher total phenolic content, followed by the young and matured leaves (p
    Matched MeSH terms: Phenols
  6. 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/analysis; Phenols/isolation & purification*; Phenols/chemistry
  7. Abdullah, Z., Halim, Z.I.A., Bakar, M.A.A., Idris, A.M.
    ASM Science Journal, 2009;3(1):39-44.
    MyJurnal
    3-Nitro-2-phenoxypyridine and 3-nitro-2-(4-methyl)phenoxypyridine were obtained when 2-chloro-3-nitropyridine was treated with phenol and p-cresol, respectively. Fluorescence studies were carried out in various solvents, in capped and uncapped conditions and for differing concentrations. Both 3-nitro-2-phenoxypyridine and 3-nitro-2-(4-methyl)phenoxypyridine were fluorescent compounds but 3-Nitro-2-(4-methyl)phenoxypyridine was more fluorescent than 3-nitro-2-phenoxypyridine in all the solvents used. The fluorescence intensity decreased with concentration and time.
    Matched MeSH terms: Phenols
  8. Azrina, A., Nurul Nadiah, M.N., Amin, I.
    MyJurnal
    The antioxidant properties of skin, flesh and kernel of Canarium odontophyllum fruit were determined. The methanolic extracts of the fruit were screened for their total phenolic content and antioxidant properties. The averaged antioxidant properties (mM TE/g FM) in skin, flesh, and kernel of Canarium odontophyllum were 16.46 ± 0.24, 20.54 ± 0.35, and 8.89 ± 0.29, respectively by DPPH assay; 151.24 ± 9.75, 70.58 ± 2.98, and 5.65 ± 0.02, respectively by FRAP assay; and 47.9 ± 0.00, 11.61 ± 1.14, and 3.00 ± 0.00, respectively by β-Carotene bleaching method. The averaged OH scavenging activity (mg DMSOE/mg FM) in skin, flesh, and kernel of Canarium odontophyllum were 43.33 ± 13.85, 7.81 ± 1.42, and 3.31 ± 0.80, respectively. While averaged total phenolic content (mg GAE/100g FM) were 387.5 ± 33.23, 267.0 ± 4.24, and 51.0 ± 0.00 for skin, flesh, and kernel respectively. Antioxidant activities were positively correlated with the total phenolic content (0.71 ≤ r ≤ 0.84).
    Matched MeSH terms: Phenols
  9. Hasmida, M.N., Nur Syukriah, A.R., Liza, M.S., Mohd Azizi, C.Y.
    MyJurnal
    In this work, the bioactive compounds which was obtained by extracting Quercus infectoria via two extraction methods; Soxhlet and supercritical carbon dioxide (SC-CO2) extraction, were analyzed using total phenolic content and DPPH (2,2-diphenyl-1-picryl hydrazyl) free radical scavenging activity analysis. The aim of this study is to compare the total phenolic content and antioxidant activity of Quercus infectoria extract acquired from SC-CO2 extraction with those from Soxhlet extraction method. The results showed the used of SC-CO2 extraction give the lowest extraction yield as compared to Soxhlet extraction. The selectivity of Q. infectoria extracts using SC-CO2 extraction was better which in contrast with Soxhlet extraction method since it shows higher total phenolic content (143.75 ± 1.06 mg GAE/g sample). This study also revealed that the extracts from both extraction methods can posses’ antioxidant activity and comparable to those obtained from commercial antioxidant.
    Matched MeSH terms: Phenols
  10. Chan, S.W., Lee, C.Y., Yap, C.F., Wan Aida, W.M., Ho, C.W.
    MyJurnal
    The objective of this study was to optimise the extraction conditions for phenolic compounds from limau purut (Citrus hystrix) peels using response surface methodology (RSM). A central composite rotatable design (CCRD) was applied to determine the effects of ethanol concentration (%), extraction temperature (oC), and extraction time (min) on total phenolic content (TPC) from limau purut (Citrus hystrix) peels. The independent variables were coded at five levels and their actual values were selected based on the results of single factor experiments. Results showed that ethanol concentration was the most significant (p
    Matched MeSH terms: Phenols
  11. 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: Phenols
  12. Fatemeh, S. R., Saifullah, R., Abbas, F. M. A., Azhar, M. E.
    MyJurnal
    The influence of variety (Cavendish and Dream), stage of ripeness (green and ripe) and parts (pulp and peel) on antioxidative compounds and antioxidant activity of banana fruit was investigated. The TPC and TFC ranged widely from 75.01 to 685.57 mg GAE/100 g and 39.01 to 389.33 mg CEQ/100 g of dry matter respectively. Cavendish banana flour contained higher TPC and TFC compared to Dream variety. TPC and TFC values of banana peel were higher than those of banana pulp. Also, green banana showed higher TPC and TFC values than those of ripe fruit. Radical scavenging activities (inhibition of DPPH) of the extracts ranged from 26.55 to 52.66%. Although Dream banana peel extracts appeared to have low TPC and TFC, its antioxidant activities were ranked moderate to high. This implies that antioxidative compounds other than phenolics and flavonoids were probably responsible for inhibition of DPPH.
    Matched MeSH terms: Phenols
  13. Tan, M. C., Tan, C. P., Khoo, H. E., Ho, C. W.
    MyJurnal
    This study aimed to optimise potential extraction conditions using response surface methodology (RSM) for yielding maximum levels of total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) scavenging capacity of henna (Lawsonia inermis) stems. The ranges for selected independent variables, namely acetone concentration (20−90%, v/v), extraction time (10−90 min), and extraction temperature (25−45°C) were identified by screening tests. Optimum conditions obtained for extraction of TPC were 47.0% acetone, extraction time of 47.6 min and extraction temperature of 37.3oC. The result also showed that 75.8% acetone, extraction time of 26.2 min and extraction temperature of 41oC yielded the highest DPPH• scavenging capacity. The optimized extraction conditions have resulted in TPC and DPPH• scavenging capacity of 5232.4 mg GAE/100 g DW and 6085.7 mg TE/100 g DW, respectively which similar to the predicted values. Therefore, RSM has successfully optimized the extraction conditions for TPC and radical scavenging capacity of henna stems.
    Matched MeSH terms: Phenols
  14. Aminah, A., Anna, P.K.
    MyJurnal
    Momordica charantia is known to contain with antioxidant properties and bioactive compounds to lower of diabetic diseases. Objective this study was investigate the influence of ripening stages on the phenolic bioactive substances and the corresponding antioxidant activity of bitter melon (Momordica charantia). The ripening of bitter melon fruit divided to four stages (RS1, RS2, RS3 and RS4). The results of this study were more ripened the fruit, lightness (L * ), yellowish (b * ) and chroma increased. Other ways, more ripened the fruit, the pH value and titratable acidity decreased. Total phenolic content and FRAF of RS 4 was highest compared other samples but DPPH of RS 4 was lowest among all the samples. However DPPH and FRAP value of bitter gourd on ripening stages showed no significant difference (p>0.05) among samples.
    Matched MeSH terms: Phenols
  15. Hismath, I., Wan Aida, W. M., Ho, C.W.
    MyJurnal
    The objective of this study was to optimise the extraction conditions for phenolic compounds from neem (Azadirachta indica) leaves using response surface methodology (RSM). A central composite rotatable design (CCRD) was applied to determine the effects of acetone concentration (%), extraction time (mins), and extraction temperature ( o C) on total phenolic content (TPC) from neem (Azadirachta indica) leaves. The independent variables were coded at five levels and their actual values were selected based on the results of single factor experiments. Results showed that acetone concentration and extraction time were the most significant (p
    Matched MeSH terms: Phenols
  16. Jemain, S.F.P., Jamal, P., Raus, A. R., Amid, A., Jaswir, I.
    MyJurnal
    Medicinal properties of Malaysian Curcuma caesia have not been studied extensively, even though it has been used as a traditional remedy. This study examined the effects of various extraction temperatures (30, 40, 50, 60, 70oC) using a high frequency (40 kHz) ultrasonic extraction method, time (30,60,90 and 120 minutes), pH (1,2,3,4,5,6,7,8,9,10) on the extraction yield of total phenolics and DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging activities from C. caesia rhizome. Extraction was most efficient at pH 6.0, while the extraction time of 30 minutes and temperature of 60oC was the best in terms of total phenolics content and DPPH scavenging activity. This study is important due to its ability to improve extraction of total phenolics compound using ultrasonic extraction method while maintaining a relatively high DPPH scavenging activity of the extracts.
    Matched MeSH terms: Phenols
  17. Aziz A, Agamuthu P, Fauziah SH
    Waste Manag Res, 2018 Oct;36(10):975-984.
    PMID: 30058954 DOI: 10.1177/0734242X18790360
    Landfill leachate contain persistent organic pollutants (POPs), namely, bisphenol A (BPA) and 2,4-Di-tert-butylphenol, which exceed the permissible limits. Thus, such landfill leachate must be treated before it is released into natural water courses. This article reports on investigations about the removal efficiency of POPs such as BPA and 2,4-Di-tert-butylphenol from leachate using locust bean gum (LBG) in comparison with alum. The vital experimental variables (pH, coagulant dosage and stirring speed) were optimised by applying response surface methodology equipped with the Box-Behnken design to reduce the POPs from leachate. An empirical quadratic polynomial model could accurately model the surface response with R2 values of 0.928 and 0.954 to reduce BPA and 2,4-Di-tert-butylphenol, respectively. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were performed on treated flocs for further understanding. FTIR analysis revealed that the bridging of pollutant particles could be due to the explicit adsorption and bridging via hydrogen bonding of a coagulation mechanism. SEM micrographs indicated that the flocs produced by LBG have a rough cloudy surface and numerous micro-pores compared with alum, which enabled the capture and removal of POPs from leachate. Results showed that the reduction efficiencies for BPA and 2,4-Di-tert-butylphenol at pH 7.5 were 76% and 84% at LBG dosage of 500 mg·L-1 and 400 mg·L-1, respectively. Coagulant dosage and pH variation have a significant effect on POPs reduction in leachate. Coagulation/flocculation using LBG could be applied for POPs reduction in leachate as a pre-treatment prior to advanced treatments.
    Matched MeSH terms: Phenols
  18. Omar, N.N., Abdullah, N., Mustafa, I.S., Sulaiman, F.
    ASM Science Journal, 2018;11(1):9-22.
    MyJurnal
    Oil palm frond is known to be the largest contributor to the oil palm residues, providing
    up to 50.3% of the total residues. Since it has a very limited utility, an initiative was taken
    by this study to investigate its suitability for bio-oil production. Hence, slow pyrolysis was
    conducted in an experimental setup equipped with a fixed bed reactor and a liquid collection
    system. From the experiments, the effect of reaction temperature on the bio-oil yield was
    examined. The characteristics of the obtained bio-oil were also investigated to study its
    potential as a substitute of phenol. It was found that at reaction temperature of 375oC,
    highest yield of bio-oil was obtained at 38.4 wt%. Meanwhile, the characteristics of oil palm
    frond and its bio-oil were found to be approximately similar to the characteristics of typical
    softwoods and their bio-oil. Most softwood biomass has been successfully used as a phenol
    substitute. Therefore, the potential of this bio-oil to be used as a phenol substitute was
    enhanced.
    Matched MeSH terms: Phenols; Polyphenols
  19. H-E. Khoo, Azlan A, Ismail A, Abas F
    Sains Malaysiana, 2013;42:949-954.
    This study aimed to determine the total phenolics and antioxidant capacity of defatted dabai parts based on liquid extraction and optimized using response surface methodology (RSM). A two-level factorial design was applied to determine the effect of two independent variables (extraction time: X1 and % methanol: X2) on three response variables (total phenolic content: Y1, total flavonoid/anthocyanin content: Y2 and Trolox equivalent antioxidant capacity: Y3). The optimum conditions for extraction time and percent methanol were 36 min or 1 min and 62.25% or 53% for the defatted dabai pulp or peel, respectively. The RSM optimized extraction was compared with sonication-assisted extraction. Optimization results showed that defatted dabai parts had high total phenolic content and antioxidant capacity. Sonication-assisted extraction utilized the optimized extraction conditions had further increased the total phenolic content and antioxidant capacity of defatted dabai peel, but not in the pulp. Therefore, optimization of different extraction methods for the defatted fruit parts is recommended for future studies.
    Matched MeSH terms: Phenols
  20. Ali Ahmadzadeh, Sarani Zakaria, Maisarah Yusoff
    The liquefaction of oil palm empty fruit bunch (EFB) in phenol was carried out in the presence of sulfuric acid as a catalyst in the reflux condenser system. The effect of initial phenol input and EFB on liquefaction reaction was investigated by measuring the reaction yield, EFB residue and combined phenol. The initial ratio of phenol to EFB has the greatest influence on the residue and reaction yield. The liquefaction products consist of some liquid by products with high amount of OH groups. The amount of this byproduct is 0.5 time of the solid product (phenolic resin).
    Matched MeSH terms: Phenols
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