Displaying publications 1 - 20 of 68 in total

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  1. Microwave-assisted extraction of polysaccharide from Cinnamomum cassia with anti-hyperpigmentation properties: Optimization and characterization studies
    Al-Ajalein AAS, Shafie MH, Yap PG, Kassim MA, Naharudin I, Wong TW, et al.
    Int J Biol Macromol, 2023 Jan 31;226:321-335.
    PMID: 36502951 DOI: 10.1016/j.ijbiomac.2022.12.023
    The anti-hyperpigmentation effect and tyrosinase inhibitory mechanism of cinnamon polysaccharides have not been reported. The current study focused on the extraction of polysaccharides from Cinnamomum cassia bark using microwave-assisted approach and optimization of the extraction process (i.e., microwave power, irradiation time and buffer-to-sample ratio) by Box-Behnken design to obtain a high yield of polysaccharides with high sun protection factor (SPF), anti-hyperpigmentation and antioxidant activities. The extracted pectic-polysaccharides had low molecular weight and degree of esterification. The optimal extraction process had polysaccharides characterized by (a) monophenolase inhibitory activity = 97.5 %; (b) diphenolase inhibitory activity = 99.4 %; (c) ferric reducing antioxidant power = 4.4 mM; (d) SPF = 6.1; (e) yield = 13.7 %. The SPF, tyrosinase inhibitory and antioxidant activities were primarily contributed by the polysaccharides. In conclusion, the polysaccharides from C. cassia could be an alternative therapeutic source for skin hyperpigmentation treatment.
    Matched MeSH terms: Monophenol Monooxygenase
  2. Essential oil composition, anti-tyrosinase activity, and molecular docking studies of Knema intermedia Warb. (Myristicaceae)
    Salihu AS, Salleh WMNHW, Setzer WN
    Z Naturforsch C J Biosci, 2023 Jul 26;78(7-8):293-298.
    PMID: 36960928 DOI: 10.1515/znc-2023-0003
    Knema is one of the genera in the Myristicaceae family. The genus includes 60 species in Southeast Asia and is traditionally used for treating skin disorders. Here, for the first time, the essential oil, anti-tyrosinase, and molecular docking studies of Knema intermedia were evaluated. The essential oil was obtained by hydrodistillation and fully characterized by gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Anti-tyrosinase activity was evaluated against mushroom tyrosinase, whereas molecular docking studies were performed using Autodock vina embedded in PyRx to evaluate the binding interactions of major components. A total of 37 components (97.3%) were successfully identified in the essential oil, which was characterized by high amounts of t-muurolol (20.1%), α-copaene (14.4%), δ-cadinene (13.9%), germacrene B (9.5%), and δ-selinene (7.0%). The essential oil displayed moderate inhibitory activity towards tyrosinase with an IC50 value of 70.2 μg/mL. The best docking energy was observed with δ-selinene (-7.8 kcal/mol), and it also forms interactions with His85, His263, and His244 which are important amino acid residues of the tyrosinase receptor. Hence, this study provides valuable scientific data on K. intermedia as potential candidate for the development of natural antiaging formulations.
    Matched MeSH terms: Monophenol Monooxygenase
  3. Review on pharmacological activities of Cinnamomum subavenium
    Lee CH, Kuo CN, Chen HL, Chen CY
    Nat Prod Res, 2013;27(11):988-91.
    PMID: 22691063 DOI: 10.1080/14786419.2012.695369
    This review describes the morphological, phytochemical and pharmacological properties of Cinnamomum subavenium (Lauraceae). The plant grows wild in southern Mainland China, Burma, Cambodia, Taiwan, Malaysia and Indonesia. This plant is recorded as having long been used to treat carcinomatous swelling, stomach ache, chest pain, abdominal pain, hernia, diarrhoea, rheumatism, nausea and vomiting. This article enumerates an overview of phytochemical and pharmacological aspects that is useful to researchers for further exploration for the necessary development of this potential herb.
    Matched MeSH terms: Monophenol Monooxygenase/antagonists & inhibitors
  4. 2-Aminothiazole-Oxadiazole Bearing N-Arylated Butanamides: Convergent Synthesis, Tyrosinase Inhibition, Kinetics, Structure-Activity Relationship, and Binding Conformations
    Raza H, Rehman Sadiq Butt A, Athar Abbasi M, Aziz-Ur-Rehman, Zahra Siddiqui S, Hassan M, et al.
    Chem Biodivers, 2023 Feb;20(2):e202201019.
    PMID: 36597268 DOI: 10.1002/cbdv.202201019
    A multi-step synthesis of novel bi-heterocyclic N-arylated butanamides was consummated through a convergent strategy and the structures of these medicinal scaffolds, 7a-h, were corroborated using spectral techniques. The in vitro analysis of these hybrid molecules revealed their potent tyrosinase inhibition as compared to the standard used. The kinetics mechanism was investigated through Lineweaver-Burk plots which exposed that, 7f, inhibited tyrosinase enzyme non-competitively by forming the enzyme-inhibitor complex. The inhibition constants Ki calculated from Dixon plots for this compound was 0.025 μM. Their binding conformations were ascertained by in silico computational studies whereby these molecules disclosed good binding energy values (kcal/mol). So, it was anticipated from the current research that these bi-heterocyclic butanamides might be probed as imperative therapeutic agents for melanogenesis.
    Matched MeSH terms: Monophenol Monooxygenase*
  5. Synthesis and Computational Exploration of Morpholine Bearing Halogenated Sulfonamides as Potential Tyrosinase Inhibitors
    Abbasi MA, Raza H, Aziz-Ur-Rehman, Siddiqui SZ, Muhammad S, Khan FM, et al.
    Chem Biodivers, 2023 Sep;20(9):e202300257.
    PMID: 37578300 DOI: 10.1002/cbdv.202300257
    In the presented work, a new series of three different 4-((3,5-dichloro-2-[(2/4-halobenzyl)oxy]phenyl)sulfonyl)morpholines was synthesized and the structure of these compounds were corroborated by 1 H-NMR & 13 C-NMR studies. The in vitro results established all the three compounds as potent tyrosinase inhibitors relative to the standard. The Kinetics mechanism plots established that compound 8 inhibited the enzyme non-competitively. The inhibition constants Ki calculated from Dixon plots for this compound was 0.0025 μM. Additionally, computational techniques were used to explore electronic structures of synthesized compounds. Fully optimized geometries were further docked with tyrosinase enzyme for inhibition studies. Reasonably good binding/interaction energies and intermolecular interactions were obtained. Finally, drug likeness was also predicted using the rule of five (RO5) and Chemical absorption, distribution, metabolism, excretion, and toxicity (ADMET) characteristics. It is anticipated that current experimental and computational investigations will evoke the scientific interest of the research community for the above-entitled compounds.
    Matched MeSH terms: Monophenol Monooxygenase*
  6. Methyl 4-pyridyl ketone thiosemicarbazone (4-PT) as an effective and safe inhibitor of mushroom tyrosinase and antibrowning agent
    Hassanuddin NA, Normaya E, Ismail H, Iqbal A, Piah MBM, Abd Hamid S, et al.
    Int J Biol Macromol, 2024 Jan;255:128229.
    PMID: 37981274 DOI: 10.1016/j.ijbiomac.2023.128229
    Enzymatic browning is of concern as it can affect food safety and quality. In this study, an effective and safe tyrosinase inhibitor and anti-browning agent, methyl 4-pyridyl ketone thiosemicarbazone (4-PT), was synthesised and characterised using Fourier-transform infrared (FTIR) spectroscopy, CHNS elemental analysis, and proton (1H) and carbon-13 (13C) nuclear magnetic resonance (NMR) spectroscopy. The vibrational frequencies of 4-PT were studied theoretically using vibrational energy distribution analysis (VEDA). Density functional theory (DFT) was applied to elucidate its chemical properties, including the Mulliken atomic charges, molecular electrostatic potential (MEP), quantum theory of atoms in molecules (QTAIM) and reduced density gradient non-covalent interactions (RDG-NCIs). Moreover, 4-PT was compared with kojic acid in terms of its effectiveness as a tyrosinase inhibitor and anti-browning agent. The toxicity and physicochemical properties of 4-PT were predicted via ADME evaluation, which proved that 4-PT is safer than kojic acid. Experimentally, 4-PT (IC50 = 5.82 μM, browning index (10 days) = 0.292 ± 0.002) was proven to be an effective tyrosinase inhibitor and anti-browning agent compared to kojic acid (IC50 = 128.17 μM, browning index (10 days) = 0.332 ± 0.002). Furthermore, kinetic analyses indicated that the type of tyrosinase inhibition is a mixed inhibition, with Km and Vmax values of 0.85 mM and 2.78 E-09 μM/s, respectively. Finally, the mechanism of 4-PT for tyrosinase inhibition was proven by 1D, second derivative and 2D IR spectroscopy, molecular docking and molecular dynamic simulation approaches.
    Matched MeSH terms: Monophenol Monooxygenase/chemistry
  7. Fulltext Characterization of two bacterial tyrosinases from the halophilic bacterium Hahella sp. CCB MM4 relevant for phenolic compounds oxidation in wetlands
    de Almeida Santos G, Englund ANB, Dalleywater EL, Røhr ÅK
    FEBS Open Bio, 2024 Dec;14(12):2038-2058.
    PMID: 39382070 DOI: 10.1002/2211-5463.13906
    Tyrosinases (TYRs) are type-3 copper proteins that are widely distributed in nature. They can hydroxylate and oxidize phenolic molecules and are mostly known for producing melanins that confer protection against photo induced damage. TYRs are also thought to play an important role in the 'latch mechanism', where high concentrations of phenolic compounds inhibit oxidative decomposition of organic biomass and subsequent CO2 release, especially relevant in wetland environments. In the present study, we describe two TYRs, HcTyr1 and HcTyr2, from halophilic bacterium Hahella sp. CCB MM4 previously isolated at Matang mangrove forest in Perak, Malaysia. The structure of HcTyr1 was determined by X-ray crystallography at a resolution of 1.9 Å and represents an uncharacterized group of prokaryotic TYRs as demonstrated by a sequence similarity network analysis. The genes encoding the enzymes were cloned, expressed, purified and thoroughly characterized by biochemical methods. HcTyr1 was able to self-cleave its lid-domain (LID) in a protease independent manner, whereas the LID of HcTyr2 was essential for activity and stability. Both enzymes showed variable activity in the presence of different metals, surfactants and NaCl, and were able to oxidize lignin constituents. The high salinity tolerance of HcTyr1 indicates that the enzyme can be an efficient catalyst in the habitat of the host.
    Matched MeSH terms: Monophenol Monooxygenase/metabolism
  8. Fulltext Estimation of Inhibitory Effect against Tyrosinase Activity through Homology Modeling and Molecular Docking
    Nokinsee D, Shank L, Lee VS, Nimmanpipug P
    Enzyme Res, 2015;2015:262364.
    PMID: 26788364 DOI: 10.1155/2015/262364
    Tyrosinase is a key enzyme in melanogenesis. Generally, mushroom tyrosinase from A. bisporus had been used as a model in skin-whitening agent tests employed in the cosmetic industry. The recently obtained crystal structure of bacterial tyrosinase from B. megaterium has high similarity (33.5%) to the human enzyme and thus it was used as a template for constructing of the human model. Binding of tyrosinase to a series of its inhibitors was simulated by automated docking calculations. Docking and MD simulation results suggested that N81, N260, H263, and M280 are involved in the binding of inhibitors to mushroom tyrosinase. E195 and H208 are important residues in bacterial tyrosinase, while E230, S245, N249, H252, V262, and S265 bind to inhibitors and are important in forming pi interaction in human tyrosinase.
    Matched MeSH terms: Monophenol Monooxygenase
  9. Deciphering the toxicological and computational assessment of Verbascum yemenese.: Integrating phytochemistry and bioinformatics tools
    Alghamdi A, A Awadh Ali N, Alafnan A, Zainal Abidin SA, Alamri A, Hussein W, et al.
    Food Chem Toxicol, 2024 Nov;193:115028.
    PMID: 39368542 DOI: 10.1016/j.fct.2024.115028
    This study explores the phytochemical composition and biological activities of Verbascum yemenense, a plant known for its medicinal properties. The plant extract revealed a rich presence of bioactive compounds that exhibited significant antioxidant properties against free radicals. The enzyme inhibition potential was particularly notable against cholinesterases (AChE: 2.56 mg GALAE/g; BChE: 1.98 mg GALAE/g), and tyrosinase (87.94 mg KAE/g), α-glucosidase suggesting potential therapeutic applications in neurodegenerative diseases, skin disorders and diabetes. Molecular docking studies and Molecular Dynamics simulations, providing insights into the interaction mechanisms of the identified compounds with the target proteins. Molecular docking studies revealed high binding affinities of the phytoconstituents, with compounds like VY4 and phyllanthusol-A (VY15) showing substantial docking scores against AChE (-9.840 kcal/mol) and BChE (-9.853 kcal/mol), respectively. For instance, the RMSD values during the MD simulations for compound VY17 in the AML complex showed a stable conformation, fluctuating within a range of 0.75 Å to 1.75 Å, indicating a strong and consistent interaction with the enzyme. MESP studies highlighted VY17's distinctive electrostatic features, notably a pronounced electronegative region, which might contribute to its binding efficiency. These findings suggest that V. yemenense is a promising candidate for developing novel therapeutic agents.
    Matched MeSH terms: Monophenol Monooxygenase/antagonists & inhibitors; Monophenol Monooxygenase/metabolism; Monophenol Monooxygenase/chemistry
  10. Development of chemometric-assisted supercritical fluid extraction of effective and natural tyrosinase inhibitor from Syzygium aqueum leaves
    Zarudin NH, Normaya E, Shamsuri SS, Iqbal A, Mat Piah MB, Abdullah Z, et al.
    Int J Biol Macromol, 2024 Feb;258(Pt 2):129168.
    PMID: 38171432 DOI: 10.1016/j.ijbiomac.2023.129168
    Tyrosinase is a key enzyme in enzymatic browning, causing quality losses in food through the oxidation process. Thus, the discovery of an effective and natural tyrosinase inhibitor via green technology is of great interest to the global food market due to food security and climate change issues. In this study, Syzygium aqueum (S. aqueum) leaves, which are known to be rich in phenolic compounds (PC), were chosen as a natural source of tyrosinase inhibitor, and the effect of the sustainable, supercritical fluid extraction (SFE) process was evaluated. Response surface methodology-assisted supercritical fluid extraction (RSM-assisted SFE) was utilized to optimize the PCs extracted from S. aqueum. The highest amount of PC was obtained at the optimum conditions (55 °C, 3350 psi, and 70 min). The IC50 (661.815 μg/mL) of the optimized extract was evaluated, and its antioxidant activity (96.8 %) was determined. Gas chromatography-mass spectrometry (GC-MS) results reveal that 2',6'-dihydroxy-4'-methoxychalcone (2,6-D4MC) (82.65 %) was the major PC in S. aqueum. Chemometric analysis indicated that 2,6-D4MC has similar chemical properties to the tyrosinase inhibitor control (kaempferol). The toxicity and physiochemical properties of the novel 2,6-D4MC from S. aqueum revealed that the 2,6-D4MC is safer than kaempferol as predicted via absorption, distribution, metabolism, and excretion (ADME) evaluation. Enzyme kinetic analysis shows that the type of inhibition of the optimized extract is non-competitive inhibition with Km = 1.55 mM and Vmax = 0.017 μM/s. High-performance liquid chromatography (HPLC) analysis shows the effectiveness of S. aqueum as a tyrosinase inhibitor. The mechanistic insight of the tyrosinase inhibition using 2,6-D4MC was successfully calculated using density functional theory (DFT) and molecular docking approaches. The findings could have a significant impact on food security development by devising a sustainable and effective tyrosinase inhibitor from waste by-products that is aligned with the United Nation's SDG 2, zero hunger.
    Matched MeSH terms: Monophenol Monooxygenase
  11. Antioxidant activities and tyrosinase inhibition effects of Phaleria macrocarpa extracts
    Nadri MH, Salim Y, Basar N, Yahya A, Zulkifli RM
    Afr J Tradit Complement Altern Med, 2014;11(3):107-11.
    PMID: 25371571
    BACKGROUND: The ethyl acetate and chloroform extracts of stems, leaves and fruits of Phaleria macrocarpa were screened for their antioxidant capacity and tyrosinase inhibition properties.

    MATERIAL AND METHOD: The total phenolic content (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and ferric-ion reducing power (FRAP) were used to evaluate their antioxidant capacity. Tyrosinase inhibition effect was measured using mushroom tyrosinase inhibition assay.

    RESULT: Ethyl acetate extract of P. macrocarpa's stem exhibited highest total phenolic content, DPPH free radical scavenging and ferric reducing power. Meanwhile, chloroform extracts of leaves and fruits demonstrated potent anti-tyrosinase activities as compared to a well-known tyrosinase inhibitor, kojic acid.

    CONCLUSION: Since chloroform extracts of leaves and fruits have low antioxidant capacities, the tyrosinase inhibition effect observed are antioxidant independent. This study suggests direct tyrosinase inhibition by chloroform extracts of Phaleria macrocarpa.

    Matched MeSH terms: Monophenol Monooxygenase/analysis; Monophenol Monooxygenase/antagonists & inhibitors*
  12. Biological activity and molecular docking studies of curcumin-related α,β-unsaturated carbonyl-based synthetic compounds as anticancer agents and mushroom tyrosinase inhibitors
    Bukhari SN, Jantan I, Unsal Tan O, Sher M, Naeem-Ul-Hassan M, Qin HL
    J Agric Food Chem, 2014 Jun 18;62(24):5538-47.
    PMID: 24901506 DOI: 10.1021/jf501145b
    Hyperpigmentation in human skin and enzymatic browning in fruits, which are caused by tyrosinase enzyme, are not desirable. Investigations in the discovery of tyrosinase enzyme inhibitors and search for improved cytotoxic agents continue to be an important line in drug discovery and development. In present work, a new series of 30 compounds bearing α,β-unsaturated carbonyl moiety was designed and synthesized following curcumin as model. All compounds were evaluated for their effects on human cancer cell lines and mushroom tyrosinase enzyme. Moreover, the structure-activity relationships of these compounds are also explained. Molecular modeling studies of these new compounds were carried out to explore interactions with tyrosinase enzyme. Synthetic curcumin-like compounds (2a-b) were identified as potent anticancer agents with 81-82% cytotoxicity. Five of these newly synthesized compounds (1a, 8a-b, 10a-b) emerged to be the potent inhibitors of mushroom tyrosinase, providing further insight into designing compounds useful in fields of food, health, and agriculture.
    Matched MeSH terms: Monophenol Monooxygenase/antagonists & inhibitors; Monophenol Monooxygenase/metabolism*
  13. Fulltext Novel biphenyl ester derivatives as tyrosinase inhibitors: Synthesis, crystallographic, spectral analysis and molecular docking studies
    Kwong HC, Chidan Kumar CS, Mah SH, Chia TS, Quah CK, Loh ZH, et al.
    PLoS One, 2017;12(2):e0170117.
    PMID: 28241010 DOI: 10.1371/journal.pone.0170117
    Biphenyl-based compounds are clinically important for the treatments of hypertension and inflammatory, while many more are under development for pharmaceutical uses. In the present study, a series of 2-([1,1'-biphenyl]-4-yl)-2-oxoethyl benzoates, 2(a-q), and 2-([1,1'-biphenyl]-4-yl)-2-oxoethyl pyridinecarboxylate, 2(r-s) were synthesized by reacting 1-([1,1'-biphenyl]-4-yl)-2-bromoethan-1-one with various carboxylic acids using potassium carbonate in dimethylformamide at ambient temperature. Single-crystal X-ray diffraction studies revealed a more closely packed crystal structure can be produced by introduction of biphenyl moiety. Five of the compounds among the reported series exhibited significant anti-tyrosinase activities, in which 2p, 2r and 2s displayed good inhibitions which are comparable to standard inhibitor kojic acid at concentrations of 100 and 250 μg/mL. The inhibitory effects of these active compounds were further confirmed by computational molecular docking studies and the results revealed the primary binding site is active-site entrance instead of inner copper binding site which acted as the secondary binding site.
    Matched MeSH terms: Monophenol Monooxygenase/antagonists & inhibitors*; Monophenol Monooxygenase/chemistry
  14. Fulltext Optimisation and Characterisation of Lipase-Catalysed Synthesis of a Kojic Monooleate Ester in a Solvent-Free System by Response Surface Methodology
    Jumbri K, Al-Haniff Rozy MF, Ashari SE, Mohamad R, Basri M, Fard Masoumi HR
    PLoS One, 2015;10(12):e0144664.
    PMID: 26657030 DOI: 10.1371/journal.pone.0144664
    Kojic acid is widely used to inhibit the browning effect of tyrosinase in cosmetic and food industries. In this work, synthesis of kojic monooleate ester (KMO) was carried out using lipase-catalysed esterification of kojic acid and oleic acid in a solvent-free system. Response Surface Methodology (RSM) based on central composite rotatable design (CCRD) was used to optimise the main important reaction variables, such as enzyme amount, reaction temperature, substrate molar ratio, and reaction time along with immobilised lipase from Candida Antarctica (Novozym 435) as a biocatalyst. The RSM data indicated that the reaction temperature was less significant in comparison to other factors for the production of a KMO ester. By using this statistical analysis, a quadratic model was developed in order to correlate the preparation variable to the response (reaction yield). The optimum conditions for the enzymatic synthesis of KMO were as follows: an enzyme amount of 2.0 wt%, reaction temperature of 83.69°C, substrate molar ratio of 1:2.37 (mmole kojic acid:oleic acid) and a reaction time of 300.0 min. Under these conditions, the actual yield percentage obtained was 42.09%, which is comparably well with the maximum predicted value of 44.46%. Under the optimal conditions, Novozym 435 could be reused for 5 cycles for KMO production percentage yield of at least 40%. The results demonstrated that statistical analysis using RSM can be used efficiently to optimise the production of a KMO ester. Moreover, the optimum conditions obtained can be applied to scale-up the process and minimise the cost.
    Matched MeSH terms: Monophenol Monooxygenase
  15. Flavonoids from the leaves and heartwoods of Artocarpus lowii King and their bioactivities
    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: Monophenol Monooxygenase
  16. Fulltext Sea grapes powder with the addition of tempe rich in collagen: An anti-aging functional food
    Permatasari HK, Nurkolis F, Vivo CD, Noor SL, Rahmawati R, Radu S, et al.
    F1000Res, 2021;10:789.
    PMID: 36237995 DOI: 10.12688/f1000research.55307.3
    Background: This study aimed to determine the potential anti-aging effects of sea grapes and tempe (fermented soybeans) collagen particle size, by measuring the activities of anti-glycation, antioxidant, and tyrosinase inhibitors. Methods: Collagen was isolated from freeze-dried sea grapes and tempe powder and treated with different NaOH concentrations (0.10 M; 0.20 M; 0.30 M), and CH 3COOH 1 M solution, separately. The collagen particle size was adjusted by stirring at 1000 rpm for 5 and 10 hours. 2,2-diphenyl-1-picrylhydrazyl (DPPH) was used to measure the antioxidant activity, and L-tyrosine and L-DOPA (l-3,4-dihydroxyphenylalanine) was used as a marker of tyrosine inhibition.  Results:  The collagen treated with 0.10 M NaOH produced the highest collagen yield (11.65%), and the largest particle size (2455 nm). Additionally, this collagen, when treated for 5 hours, exhibited 24.70% antioxidant activity, 62.60% anti-glycation, 8.97% L-tyrosine, and 26.77% L-Dopa inhibition activities. Meanwhile, the collagen treated for 10 hours had a 9.98% antioxidant activity, 41.48% anti-glycation, 7.89% L-tyrosine, and 2.67% L-Dopa inhibition activity.  Conclusion: Sea grapes and tempe collagen powder treated with 0.10 M NaOH and stirred for 5 hours, possess the best potential anti-aging properties as a functional food.
    Matched MeSH terms: Monophenol Monooxygenase
  17. Fulltext An optical test strip for the detection of benzoic acid in food
    Hamzah HH, Yusof NA, Salleh AB, Bakar FA
    Sensors (Basel), 2011;11(8):7302-13.
    PMID: 22164018 DOI: 10.3390/s110807302
    Fabrication of a test strip for detection of benzoic acid was successfully implemented by immobilizing tyrosinase, phenol and 3-methyl-2-benzothiazolinone hydrazone (MBTH) onto filter paper using polystyrene as polymeric support. The sensing scheme was based on the decreasing intensity of the maroon colour of the test strip when introduced into benzoic acid solution. The test strip was characterized using optical fiber reflectance and has maximum reflectance at 375 nm. It has shown a highly reproducible measurement of benzoic acid with a calculated RSD of 0.47% (n = 10). The detection was optimized at pH 7. A linear response of the biosensor was obtained in 100 to 700 ppm of benzoic acid with a detection limit (LOD) of 73.6 ppm. At 1:1 ratio of benzoic acid to interfering substances, the main interfering substance is boric acid. The kinetic analyses show that, the inhibition of benzoic is competitive inhibitor and the inhibition constant (K(i)) is 52.9 ppm. The activity of immobilized tyrosinase, phenol, and MBTH in the test strip was fairly sustained during 20 days when stored at 3 °C. The developed test strip was used for detection of benzoic acid in food samples and was observed to have comparable results to the HPLC method, hence the developed test strip can be used as an alternative to HPLC in detecting benzoic acid in food products.
    Matched MeSH terms: Monophenol Monooxygenase/chemistry
  18. Identification of metabolites from phenanthrene oxidation by phenoloxidases and dioxygenases of Polyporus sp. S133
    Hadibarata T, Tachibana S, Askari M
    J Microbiol Biotechnol, 2011 Mar;21(3):299-304.
    PMID: 21464602
    Phenanthrene degradation by Polyporus sp. S133, a new phenanthrene-degrading strain, was investigated in this work. The analysis of degradation was performed by calculation of the remaining phenanthrene by gas chromatography-mass spectrometry. When cells were grown in phenanthrene culture after 92 h, all but 200 and 250 mg/l of the phenanthrene had been degraded. New metabolic pathways of phenanthrene and a better understanding of the phenoloxidases and dioxygenase mechanism involved in degradation of phenanthrene were explored in this research. The mechanism of degradation was determined through identification of the several metabolites; 9,10-phenanthrenequinone, 2,2'-diphenic acid, salicylic acid, and catechol. 9,10-Oxidation and ring cleavage to give 9,10-phenanthrenequinone is the major fate of phenanthrene in ligninolytic Polyporus sp. S133. The identification of 2,2'-diphenic acid in culture extracts indicates that phenanthrene was initially attacked through dioxigenation at C9 and C10 to give cis-9,10-dihydrodiol. Dehydrogenation of phenanthrene-cis-9,10-dihydrodiol to produce the corresponding diol, followed by ortho-cleavage of the oxygenated ring, produced 2,2'-diphenic acid. Several enzymes (manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase, and 2,3-dioxygenase) produced by Polyporus sp. S133 was detected during the incubation. The highest level of activity was shown at 92 h of culture.
    Matched MeSH terms: Monophenol Monooxygenase/metabolism*
  19. Phenolic components and assessment of biological properties of Tchihatchewia isatidea Boiss. extracts: Docking and functional approaches for designing novel products
    Zengin G, Abdallah HH, Dogan A, Mollica A, Aumeeruddy-Elalfi Z, Mahomoodally MF
    Food Chem Toxicol, 2018 Jan;111:423-431.
    PMID: 29198858 DOI: 10.1016/j.fct.2017.11.055
    The potentiality of bioactive phenolic compounds may result in plant extracts having multiple biological activities. The aim of this study was to investigate into the biological activities of the methanolic, ethyl acetate, and water extracts of Tchihatchewia isatidea Boiss, an endemic medicinal plant of Turkey. The phenolic compositions of the extracts were confirmed using RP-HPLC. Extracts were screened for their potential antioxidant through a panoply of assays; their anti-diabetic potential, and plausible inhibitory activity against tyrosinase and acetylcholinesterase. Molecular modelling methods were also used to assess the docking properties of phenolic compounds on tyrosinase. The major and most abundant compounds were rosmarinic acid (570 ± 14 μg/g extract in the methanolic extract), ferrulic acid (336 ± 6 μg/g extract in the methanolic extract), (+)-catechin (340 ± 4 μg/g extract in the water extract), apigenin (182 ± 4 μg/g extract in the methanolic extract), and epicatechin (188 ± 12 μg/g extract in the water extract). Radical scavenging, reducing capacity, and metal chelating activities were detected in the extracts, with preponderance activity observed in the methanolic extract. In conclusion, the potential clinical applications observed during this study may provide new insights into the molecular aspect particularly for neuroprotective and anti-diabetic mechanisms involving oxidative stress.
    Matched MeSH terms: Monophenol Monooxygenase/metabolism
  20. Antioxidative, tyrosinase inhibiting and antibacterial activities of leaf extracts from medicinal ferns
    Lai HY, Lim YY, Tan SP
    Biosci Biotechnol Biochem, 2009 Jun;73(6):1362-6.
    PMID: 19502733
    Leaf extracts of five medicinal ferns, Acrostichum aureum L. (Pteridaceae), Asplenium nidus L. (Aspleniaceae), Blechnum orientale L. (Blechnaceae), Cibotium barometz (L.) J. Sm. (Cyatheaceae) and Dicranopteris linearis (Burm.) underwood var. linearis (Gleicheniaceae), were investigated for their total phenolic content (TPC), and antioxidative, tyrosinase inhibiting and antibacterial activities. The antioxidative activity was measured by assays for radical scavenging against 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric ion reducing power (FRP), beta-carotene bleaching (BCB) and ferrous ion chelating (FIC). The results revealed B. orientale to possess the highest amount of total polyphenols and strongest potential as a natural antioxidative, tyrosinase inhibiting and antibacterial agent as demonstrated by its strong activities in all related bioassays. The other ferns with antioxidative potential were C. barometz and D. linearis. Except for A. aureum, all ferns showed antibacterial activity which may justify their usage in traditional medicines.
    Matched MeSH terms: Monophenol Monooxygenase/antagonists & inhibitors*
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