Curcumin solution

The quantitative determination is carried out colorimetrically in the same way with a weighed quantity of the sample. The coloration of the liquid is compared (as in estimating potassium nitrate) with a series of tubes in which solutions containing definite proportions of boric add (o-i, 02, 0-3, etc., %) are treated with the same amounts of add, alcohol and curcumin solution in each case. 

F - Curcumine solution 250 ml of a mixture of alcohol and water having a specific density of 0.809 to 0.810 is prepared at 20°C. To 175 ml of this mixture, 3.75 g oxalic acid (H2C20. 2H20), 6.25 ml hydrochloric acid (d = 1.19), 19 ml water and 87.5 mg curcumine are added in a 250 ml calibrated quartz flask. The reagent is then shaken in the light protected calibrated flask until all is dissolved, and the solution is diluted to the mark with the remaining alcohol-water mixture. The solution is stable for at least 2 months when stored cool and dark. 

Curcumin (indicator) prepare a saturated aqueous solution pH range yellow 6.0-8.0 brownish red. 

Regarding the data concerning the stability of curcumin in solution, it is advisable to perform extraction under acidic conditions and to avoid direct light exposure. However, it will also depend on the material from which curcumin has to be extracted. 

Wang, Y.J. et al., Stability of curcumin in buffer solutions and characterization of its degradation products, J. Pharm. Biomed. Anal, 15, 1867, 1997. 

Tonnesen, H.H. and Karlsen, J., Studies on curcumin and curcuminoids. VI. Kinetics of curcumin degradation in aqueous solution, Z. Lebensm. Unters. Forsch., 180, 402, 1985. 

A systematic study was carried out using in parallel 50 standard solutions for each concentration of three natural colorants (curcumin, carminic acid, and caramel as yellow, red, and brown, respectively). No false positive results for synthetics were obtained up to concentrations of 15 and 20 ng/ml for natural red and yellow colorants, respectively, or 110 ng/ml for natural brown colorant. The concentrations have to be high enough to prove that the screening method is able to accurately discriminate natural and synthetic colorants. To make a clear interpretation of the quantitative UV-Vis spectrum, linear regression analysis was used. Quantitative UV-Vis analysis of a dye ° can be calculated according to the following formula ... 

Various chromogenic reagents have been used for the spectrophotometric determination of boron in seawater. These include curcumin [108,109], nile blue [110], and more recently 3,5 di-tert butylcatechol and ethyl violet [111]. Uppstroem [108] added anhydrous acetic acid (1 ml) and propionic anhydride (3 ml) to the aqueous sample (0.5 ml) containing up to 5 mg of boron per litre as H3BO3 in a polyethylene beaker. After mixing and the dropwise addition of oxalyl chloride (0.25 ml) to catalyse the removal of water, the mixture is set aside for 15-30 minutes and cooled to room temperature. Subsequently, concentrated sulfuric-anhydrous acetic acid (1 1) (3 ml) and curcumin reagent (125 mg curcumin in 100 ml anhydrous acetic acid) (3 ml) are added, and the mixed solution is set aside for at least 30 minutes. Finally 20 ml standard buffer solution (90 ml of 96% ethanol, 180 g ammonium acetate - to destroy excess of protonated curcumin - and 135 ml anhydrous acetic acid diluted to 1 litre... 

Aznarez et al. [2] have described a Spectrophotometric method using curcumin as chromopore for the determination of boron in soil. Boron is extracted from the soil into methyl isobutyl ketone with 2-methylpentane-2,4-diol. In this method 0.2-lg of finely ground soil is digested with 5ml concentrated nitric-perchloric acid (3 + 1) in a polytetrafluoroethylene lined pressure pump for 2h at 150°C. The filtrate is neutralized with 6M sodium hydroxide and diluted to 100ml with hydrochloric acid 1+l.This solution is triple extracted with 10ml of methyl isobutyl ketone to remove iron interference. This solution is then extracted with 10ml 2-methyl pentane-2,4 diol and this extract dried over anhydrous sodium sulphate. 

Materials Required Salbutamol sulphate 50 mg solution of an equimolar mixture of anhydrous sodium carbonate and potassium carbonate (3% w/v in DW) 5.0 ml Solution of curcumin (0.125% w/v in glacial acetic acid) 3.0 ml mixture of H2S04 and glacial CH3COOH (5 ml 5 ml) 3.0 ml ethanol (96%) 100 ml solution of boric acid (dissolve 5 g of boric acid in a mixture of 20 ml DW and 20 ml absolute ethanol and dilute to 250 ml with absolute ethanol) 100 ml. 

Also, boron can be analyzed by colorimetry techniques (APHA, AWWA, and WEF. 1999. Standard Methods for the Examination of Water and Wastewater, 20th ed. Washington DC American Public Health Association). Boron in acidified aqueous phase reacts with curcumin to form a red-colored product, roso-cyanine. Presence of calcium and magnesium at high concentrations can interfere in the test. Another colorimetric measurement involves the reaction of boron with carmine or carminic acid in concentrated sulfuric acid. The color of the solution changes from bright red to bluish red or blue, depending on boron concentration. 

Anaiysis. If a borate is treated with H2SO4 and methanol H3COH, methyl borate is produced. If a small amount of the mixture is introduced to a flame, a green flame color is produced. The test is sensitive to 20 ppm of B. Ba and Cu interfere, both of these also giving a green color. A spot test with curcumin will detect 5 ppm of B. Titration of H3BO3 in a mannitol solution... 

The curcumin may be prepared as follows 30 grams of turmeric powder (Curcuma tonga) are dried at ioo° and then treated for four hours in an extraction apparatus with petroleum ether. The dry, defatted powder is then extracted in the same apparatus with 100 c.c. of benzene for 8—10 hours on cooling, the benzene solution deposits the curcumin as a fine, yellowish, crystalline powder. 

To prepare solutions or curcumin paper, o-io gram of the turmeric is dissolved in 100 c.c. of 90% alcohol. 

If the test gives a positive result, a 1% boric acid solution is prepared and with varying quantities of this a series of tests are made with the same amounts of add, alcohol and curcumin as are used in the case of the wine. By comparison of the colours, the amount of boric add in the wine may be judged. 

Indian yellow, fast yellow, azo flavine, brilliant yellow S, curcumine, orange II, palatine light yellow, wool fast yellow, azo acid yellow, azo yellow, etc. ° Solution becomes red or orange red. 

Anand P, Sundaram C, Jhurani S, Kunnumakkara AB, Aggarwal BB. 2008. Curcumin and cancer An old-age disease with an age-old solution. Cancer Lett 267 133-164. 

Figure 6.1. Adsorption spectra of A reagent blank solution measured against IBMK as reference, B Boron curcumin compound against reagent blank, 3 jxg/1 boron, and C as , 5 xg/l of boron. From [2]...

Procedure Determine the absorbance of each solution in 1-cm cells at the wavelength of maximum absorption at about 421 nm with a suitable spectrophotometer, using acetone as the blank. Calculate the percentage of curcumin in the sample by the formula... 

Tonnesen HH. Studies on curcumin and curcuminoids. XXVIII. Solubility, chemical and photochemical stability of curcumin in surfactant solution. Pharmazie 2002 57 ... 

The antibacterial activity of curcumin is greatly enhanced by UV-VIS radiation (5). Photodegraded solutions of thiomerosal were found to be more active... 

Solutions of phenylephrine hydrochloride, for example, develop a brown color as a result of photodegradation (2). Many dyes, including FD C dyes, used for coloring liquid pharmaceutical preparations such as syrups and elixirs, fade on exposure to light (9). Curcumin, a natural food colorant, fades on exposure to UV-VIS radiation (10). 

Some of the dyes that are photolabile have been reported to cause phototoxic effects. For example, curcumin has demonstrated phototoxicity to mammalian cells (20). Methylene blue in eye solutions was reported to induce toxic effects (21). It is important, therefore, that drugs and excipients used in product formulations be screened for their photostability as well as photosensitizing effects. 

Thoma and Klimek (115) also found that the natural food colorant curcumin as well as Fast Yellow, chrysoine, apocarotinol, and, cochineal Red A photostabi-lized solutions of nifedipine and nitrofurazone. They also found that vanillin and methyl gallate could stabilize solutions of dihydroergotamine. These authors also found that furosemide was stabilized by the addition of vanillin, haloperidol by benzyl alcohol, and vanillin and thiothixene by quinosol and vanillin. 

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