Determination of anti-tyrosinase activity of acetone extracts from selected Potentilla L. species.

2021 ◽  
Author(s):  
D Augustynowicz ◽  
K Jakimiuk ◽  
J W Strawa ◽  
M Tomczyk
Keyword(s):  
Tyrosinase Activity ◽  
Acetone Extracts

Studies on the Acetone Extraction of Raw Rubber

1935 ◽  
Vol 8 (4) ◽  
pp. 604-612
Author(s):  
Hidemaro Endô
Keyword(s):  
Acid Value ◽  
Acetone Extract ◽  
Water Bath ◽  
Acetone Extraction ◽  
Saponification Value ◽  
Alcoholic Potash ◽  
Saponifiable Matter ◽  
Acetone Extracts ◽  
Hcl Solution

Abstract (1) For the determination of the saponification value of the acetone extract, 20 cc. 0.2 N alcoholic potash is added to the extract and the flask is heated on a water bath for 60 minutes. It is then titrated with 0.1 N HCl solution, using phenolphthalein as indicator. (2) When the saponification values of the acetone extracts of 8, 16, and 24 hours are compared, the saponification value of the 8 hour extract is seen to be high, while those of 16 and 24 hour extracts are low. This indicates (a) that the 8 hour extract contains a higher percentage of saponifiable matter than the 16 and 24 hour extracts; (b) the quantity of rubber hydrocarbon which is dissolved in the acetone extract increases with increasing time of extraction, and (c) the acid value of the acetone extract decreases during the period of extraction from 16 to 24 hours. (3) Regarding the saponification values (R) of the acetone extracts of 8, 16, and 24 hours, similar remarks may be made as in (2) above.

A colorimetric and near -infrared ratiometric fluorescent probe for the determination of endogenous tyrosinase activity based on cyanine aggregation

The Analyst ◽  
2019 ◽  
Vol 144 (18) ◽  
pp. 5472-5478 ◽  
Author(s):  
Peng Zhang ◽  
Shasha Li ◽  
Caixia Fu ◽  
Qian Zhang ◽  
Yuzhe Xiao ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Near Infrared ◽  
High Sensitivity ◽  
Tyrosinase Activity ◽  
Cyanine Dye ◽  
Ratiometric Fluorescent Probe

A ratiometric fluorescent probe for TYR activity with high sensitivity was developed based on the H-aggregation of a cyanine dye.

scholarly journals An electrometric method for the determination of tyrosinase activity

1985 ◽  
Vol 229 (3) ◽  
pp. 573-578 ◽  
Author(s):  
F Solano-Muñoz ◽  
R Peñafiel ◽  
J D Galindo
Keyword(s):  
Continuous Method ◽  
Tyrosinase Activity ◽  
Proton Release ◽  
Electrometric Method ◽  
Proton Uptake ◽  
Net Release

The pathway of dopachrome formation from L-dopa involves the net release of one proton for each molecule of dopachrome formed. The protons produced as a consequence of the enzymic step catalysed by tyrosinase can be measured by an electrometric device able to monitor changes in H+ concentration below 1 microM. This electrometric recording can be used as a simple, sensitive and continuous method for determining tyrosinase activity. The electrometric method can also be used in the presence of ascorbate by the spontaneous coupling of ascorbate oxidation to dopaquinone reduction, but measuring proton uptake instead of proton release.

scholarly journals Simultaneous Determination of Six Isoflavones from Puerariae Lobatae Radix by CPE-HPLC and Effect of Puerarin on Tyrosinase Activity

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 344 ◽  
Author(s):  
Limin Qu ◽  
Ke Song ◽  
Qi Zhang ◽  
Jie Guo ◽  
Juan Huang
Keyword(s):  
High Performance ◽  
Equilibrium Temperature ◽  
Extraction Yield ◽  
Tyrosinase Activity ◽  
Ultrasound Assisted Extraction ◽  
Solid Ratio ◽  
Assisted Extraction ◽  
Triton X ◽  
Diphenolase Activity

Tyrosinase inhibitors with excellent inhibitory activities and lower side effects have promising applications in the fields of medicine, agriculture, food sciences and cosmetics. In this study, a method for simultaneous separation and determination of six target compounds (puerarin, daidzin, genistein, daidzein, genistin, and formononetin) in Puerariae Lobatae Radix was established by cloud point extraction (CPE) and concentration combined with high performance liquid chromatography (HPLC). To achieve high extraction yields, an ultrasound-assisted extraction method was developed based on a salt-modified Triton X-100 system. The optimal extraction conditions are: surfactant Triton X-100 concentration 0.07 g/mL, liquid-solid ratio 80:1 (mL/g), NaCl addition amount 0.6 g, equilibrium time 40 min, equilibrium temperature 70 °C. Under the optimal conditions, the total maximum extraction yield of the six target isoflavones reached 8.92 mg/g. Using l-tyrosine and l-dopa as substrates, the effects of puerarin on the monophenolase and diphenolase activity of tyrosinase activity were investigated by the enzyme kinetics method. The results showed that puerarin inhibited monophenolase activity with an IC50 of 0.537 mg/mL and activated diphenolase activity. The inhibition type of puerarin on monophenolase and the activation type of puerarin on diphenolase were analyzed by Lineweaver-Burk plots which show that puerarin showed mixed inhibition on monophenolase and mixed activation on diphenolase. Therefore, puerarin can be used as both a tyrosinase inhibitor and a tyrosinase activator.

Determination of Usnic Acid in Some Rhizoplaca Species from Middle Anatolia and their Antimicrobial Activities

2006 ◽  
Vol 61 (1-2) ◽  
pp. 47-51 ◽  
Author(s):  
Demet Cansaran ◽  
Demet Çetin ◽  
M. Gökhan Halıcı ◽  
Orhan Atakol
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Bacillus Subtilis ◽  
Enterococcus Faecalis ◽  
Usnic Acid ◽  
Dry Weight ◽  
Antimicrobial Activities ◽  
Acetone Extracts

Abstract Three species of lichens, Rhizoplaca chrysoleuca (Sm.) Zopf, Rhizoplaca melanopthalma (DC.) Leuckert & Poelt and Rhizoplaca peltata Ramonds Leuckert, were collected from middle Anatolia, Erciyes Mountain (Kayseri) in Turkey. Their usnic acid amounts were determined by HPLC in acetone extracts. In addition, antimicrobial activities of these extracts were determined against Escherichia coli (ATCC 35218), Enterococcus faecalis (RSKK 508), Proteus mirabilis (Pasteur Ens. 235), Staphylococcus aureus, Bacillus subtilis, Bacillus megaterium and Pseudomonas aeruginosa. It was shown that, as the usnic acid amount increased, the antimicrobial activities increased too. The usnic acid contents of Rhizoplaca species varied between 0.19-4.0% dry weight

scholarly journals PENETAPAN KADAR FENOL TOTAL DAN KATEKIN DAUN TEH HITAM DAN EKSTRAK ASETON TEH HITAM DARI TANAMAN CAMELLIA SINENSIS VAR. ASSAMICA

Jurnal Kimia ◽  
2020 ◽  
pp. 43
Author(s):  
N. L. P. V. Paramita ◽  
N. P. T. W. Andari ◽  
N. M. D. Andani ◽  
N. M. P. Susanti
Keyword(s):  
Camellia Sinensis ◽  
Black Tea ◽  
Acetone Extract ◽  
Total Phenol ◽  
Total Phenol Content ◽  
Phenol Content ◽  
Tea Leaves ◽  
Tea Leaf ◽  
Acetone Extracts

Indonesia is quite well known as one of the countries that has tea plantations and uses its own production of tea. As a tea producing country, Indonesia has been able as a tea exporter. The most tea production in Indonesia is black tea product. Black tea products are produced from species Camellia sinensis Var. Assamica which undergoes an enzymatic oxidation process to fresh tea leaves. The most phenolic compounds contained in the black tea leaf are catechins, theaflavins, and thearubigin. The purpose of this study was to determine the phenolic total and catechin content of black tea products and acetone extracts produced by D'wan Tea (DT) and Bali Cahaya Amertha (BCA) plantations which located in Tabanan district, Bali. Determination of total phenol was carried out on black tea leaf products and acetone extract using the Folin-Ciocalteu method compared with gallic acid standards. Determination of catechin content was performed on fresh (before oxidized) tea leaves, black tea leaf products, and acetone extracts using the UV-Vis Spectrophotometry method at a maximum wavelength of 257 nm. The results showed that total phenol content of D'wan Tea black tea products (SDT) and Bali Cahaya Amerta (SBCA) were 1.50 ± 0.02 % mg GAE/g dan 0.97 ± 0.02 % mg GAE/g, respectively. Results of the total phenol content of D'Awan Tea (EADT) black tea acetone extract was 6.92 ± 0.12 % mg GAE/g, while the Bali Cahaya Amerta (EABCA) black tea acetone extract was 7.38 ± 0.07 % mg GAE/g. Catechin content from fresh leaf samples of D'wan Tea (SSDT), SDT, and EADT were 15.30 ± 0.22 % mg/g, 8.37 ± 0.13 % mg/g, and 37.45 ± 0.74 % mg/g. Catechin content of fresh leaf samples of Bali Cahaya Amerta (SSBCA), SBCA, and EABCA were 14.71 ± 0.28 % mg/g, 15.16 ± 0.58 % mg/g, and 35.66 ± 0.89 % mg/g. Total phenol content of DT black tea products is greater than BCA black tea products. DT black tea products appear to have decreased catechins in processing. In the processing of black tea it is necessary to decrease catechins content due to the formation of catechin polymers, namely theaflavin and thearubigin as a determinant of the quality of black tea.   Keywords: black tea, Camellia Sinensis, cathecin, total phenol.

Flavanoids from Dalea elegans: Chemical reassignment and determination of kinetics parameters related to their anti-tyrosinase activity

2014 ◽  
Vol 10 ◽  
pp. 260-267 ◽  
Author(s):  
Mariana Andrea Peralta ◽  
María Daniela Santi ◽  
Alicia Mariel Agnese ◽  
José Luis Cabrera ◽  
María Gabriela Ortega
Keyword(s):  
Tyrosinase Activity ◽  
Kinetics Parameters

scholarly journals Suitable extraction conditions for determination of total anti-oxidant capacity and phenolic compounds in Ruspolia differens Serville

2020 ◽  
pp. 1-10
Author(s):  
G. Ssepuuya ◽  
J. Kagulire ◽  
J. Katongole ◽  
D. Kabbo ◽  
J. Claes ◽  
...  
Keyword(s):  
Total Phenolics ◽  
Total Flavonoids ◽  
Active Components ◽  
Active Compounds ◽  
Solvent Type ◽  
Anti Oxidant ◽  
Removal Of Fat ◽  
Acetone Extracts

Recent research on edible insects’ composition has placed more emphasis on the quantity and quality of macro- and micro- nutrients and less emphasis on their bio-active components. This study aimed at assessing the effect of four factors, namely: defatting, solvent type (ethanol, methanol and acetone), solvent concentration (50, 75 and 100%) and extraction time (15, 30, 45 and 60 minutes) on the extraction efficiency, the total anti-oxidant activity and the amount of total phenolics and total flavonoids of Ruspolia differens. It was not known if the removal of fat (defatting) would influence the total anti-oxidant activity, and the distribution of anti-oxidant compounds in the R. differens matrix. Non-defatting use of acetone and sonication for 60 minutes are associated with high anti-oxidant activity and high amounts of bio-active compounds extracted. Aqueous acetone (50%) extracts had the highest average anti-oxidant activity (87.00±2.59% RSA) while 100% acetone extracts had the highest average total phenolics (11.14±0.18 GAE/g) and average total flavonoids (3.02±0.21 QE/g) content, indicating the presence of other, possibly highly polar, bio-active compounds in R. differens.

scholarly journals Alkylresorcinols in rye (Secale cereale L.) grains. I. Micromethod for determination of alkyl derivatives of resorcinol in rye grain

2015 ◽  
Vol 44 (4) ◽  
pp. 479-489 ◽  
Author(s):  
W. Mejbaum-Katzenellenbogen ◽  
F. Tłuścik ◽  
A. Kozubek ◽  
A. Sikorski
Keyword(s):  
Preparative Thin Layer Chromatography ◽  
Uv Spectrum ◽  
Selective Determination ◽  
Alkyl Derivatives ◽  
Secale Cereale L ◽  
Spectrum Characteristic ◽  
Acetone Extracts ◽  
Layer Chromatography ◽  
Derivatives Of

A pure preparation of alkylresorcinol from rye grains was obtained by preparative thin-layer chromatography, which gave a UV spectrum characteristic for 5-n-alkylresorcinols and orcinol. This preparation served as standard in the elaboration of a micro method (for alkylresorcinols determination in acetone extract from rye grain. It was found that this method is suitable for selective determination of 5-n-alkylrezorcinols in acetone extracts from rye grains.

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