OXIDATION O F CARBOHYDRATES, FATS, AliD XITROGESOCS PRODUCTS BY AIR IX PRESEKCE OF SUNLIGHT B Y C. C. PALIT AND N. R. DHAR
In foregoing publications’ we have shown that different carbohydrates, nitrogenous products, alcohols, etc. which are not ordinarily oxidised by air, are readily oxidised by air in presence of reducing agents like sodium sulphite, ferrous hydroxide, cerous hydroxide, manganous hydroxide and other reducing agents. In a recent communication2 we have shown that methyl alcohol, ethyl alcohol, and glycerol can be oxidised by passing air a t the ordinary temperature in presence of sunlight. Noreover several years ago, one of us3 pointed out that reactions which are sensitive to the influence of light are also induced to take place in presence of another chemical change of the same type. I n this paper, we are recording the experimental results obtained in the 3xidation of several carbohydrates, urea, glycine, hippuric acid, potassium stearate, palmitate and oleate by passing air through these solutions in presence of tropical sunlight. Glass bottles containing solutions of various substances were exposed to sunlight and a definite volume of air was passed through them; and the amounts of unoxidised substances were estimated after passing 36. j litres of air in 5 ; hours. I n these experiments, a slow current of air was passed through a series of bottles containing solutions of carbohydrates, nitrogenous substances and fats respectively. I n each case I O cc. of the solutions under investigation were taken and the volume was made up to I O O cc. I n the case of carbohydrates and glycogen, these were estimated after hydrolysis when necessary by reduction of Fehling’s solution. The cuprous oxide obtained was collected, dried, and ignited in a crucible and weighed as cupric oxide. I n case of nitrogenous substances, urea was estimated by freshly prepared alkaline solution of sodium hypobromite in an ureometer. After introduction of a known volume of solution of urea, the whole system was set apart over night and the readings noted on the following day. By this method, an accurate result was obtained and the necessary correction was not needed a t all. Uric acid was determined by treating the solution with concentrated H2S0, and then titrating against standard potassium permanganate solution whilst the solution was hot. The amino-acids, viz. glycine, alanine, and hippuric acid, were estimated by adding I O cc. of neutralised solution of formaldehyde ( I part formaldehyde diluted with z parts of water) and titrating the mixture with K / I O sodium hydroxide solution using phenolphthalein as indicator. This method
’ J. Phys. Chem., 29, 376 (1925); 3 0 , 939 (1926).
* J. Phys.
Chem., 29, 926 (1925).
J. Chem. SOC.,111, 694 (1917).
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C . C. PALIT h S D S . R. DHAR
of determination gives accurate results. The fats viz. potassium stearate, potassium oleate and potassium palmitate were treated with I O cc. of iodine trichloride and kept for 2 hours in the dark;and then the whole solution was treated with Kj~osodium thiosulphate solution by adding potassium iodide solution. The following experimental results were obtained. T.4BLE I (-4) In each of these experiments, the volume of air passed was 36.5 litres in 53 hours Actual weight of Amount of s o . of Substance used Percent age
Experi- in the experiment ment
I
z 3 4
5 6 7 8 9
Galactose Arabinose Cane sugar Glucose Laevulose Lactose Maltose Starch Glycogen
substance In I O cc. substance oxiof the solution dised in grm. taken in grm. (Blank)
0.0861 0.1000
0.0059 0.0060
amount of substance oxidised
6.8 6.0 7.4 7.9 8.6 16.2
0.0964 0.0962 0.09185 0.0997 0,1097
0,0076 0.0079 0.0142 0,0220
20.0
0.1027
0.0366
0.0987
0.0157
35.6 15.9
0.0071
TABLE 1 (B) I n each of these experiments, the volume of air passed was 36.5 litres in ~f hours
Xo. of Substance Exp9i-1- used in the ment experiment
I 2
3 4
5 6 7 8 9
Arabinose Galactose Cane sugar Glucose Laevulose Lactose Maltose Starch Glycogen
Amount of Actual weight of substance in I O cc. substance oxidised in grm. of the solution taken in grm. (Blank) 0.1000
0.0075
0.0861 0.0964 0.0962 0.09185 0.0977 0.1097
0.0067 0.0098 0.0144 0.0159 0.0197 0.028; 0.0399 0.0987
0.1027
0.0987
Percent age amount of substance oxi. dised
7.5 7.8 IO.2
14.9 17.3 19.7 25.9 38.8 19.7
S . B.
I n these experiments, the intensity of light was greater than that in previous experiments shown in Table I (A).
The results prove conclusively that solutions of cane sugar, glucose, galactose, maltose, laevulose, lactose, arabinose, starch, and glycogen can be oxidised by passing air through these solutions in presence of sunlight.
126j
O X I D h T I O S BY A I R I S PRESESCE O F SUNLIGHT
The amounts of oxidation of the various carbohydrates are in the following decreasing order:- Starch ) maltose ) lactose ) laevulose ) glucose ) cane sugar ) galactose ) arabinose. We have repeatedly observed that the amount of oxidation varies as the intensity of light [Vide Table I (B)]. Having obtained the results to show that oxidation of the carbohydrates does take place in presence of sunlight, we carried on experiments with certain nitrogenous substances and the results given in Table I1 were obtained. a
TABLE I1 In each of these experiments, the volume of air passed was 36.j litres in j+ hours Amount of Actual weight of substance in I O cc. substance oxidised in grm. of the solution taken in grm. (Blank)
So. of Substance Experi- used in the ment experiment
I
2
3 4 j
Urea Glycine a-Alanine Hippuric acid Sodium urate
0.2000
0,0175
0.0999 0.0997 0.0483 0.0420
0.0096 0.036j 0.0069 0.00825
Percentage amount of substance oxidised
8.7 9.6 36.6 14.2 19.6
The foregoing results prove that solutions of urea, uric acid, hippuric acid, glycine, alanine, etc., can be oxidised in presence of sunlight by passing air. Yext we have investigated the oxidation of potassium stearate, potassium palmitate] and potassium oleate and have obtained the results given in Table 111. TABLE 111 Experiments with fats. The volume of air passed was 36. j litres in 5 8 hours. I O cc. of iodine trichloride I O cc. of IO%, potassium iodide solution = 16.0 cc. of S / I Osodium thiosulphate
+
s o . of Experiment
I
z
3
Substance used in the experiment
Potassium stearate Potassium oleate Potassium palmitate
Volume in cc. of X / i o sodium thiosulphate re uired for io cc. fat taken. (Blank)
07
Volume in cc. of Percentage S , i o sodium thio- amount sulphate required of fat for fat left after oxidised the experiment
Ij.2j
15.55
40
10.45 13.5j
12.2
31.5
14.45
36.7
Hence these fatty substances are also oxidised by passing air in presence of sunlight. The foregoing experimental results show that carbohydrates, nitrogenous matters and fatty substances have been oxidised for the first, time simply by passing air in presence of sunlight; and these results are likely to throw considerable light on understanding the use of sunlight and artificial lights in the treatment of several diseases.
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C. C. PALIT AND 9.R. DHAR
We have also tried to oxidise solutions of sodium nitrite, sodium arsenite, arsenious acid, and potassium oxalate in presence of sunlight by passing air. No oxidation was observed with sodium nitrite, sodium arsenite and arsenious acid. The results obtained with KzCzOl are given in Table IT.
TABLE IV Experiment with potassium oxalate. I n this experiment, the volume of air passed was 36.5 litres in 53 hours. I O cc. of potassium oxalate E 15.4cc. of N / I O KMnOl s o . of Substance ExDeri- used in ment the experiment
I
2
Volume in cc. of K!IO K M n 0 4 requred for I O cc. of potassium oxalate (Blank)
Potassium oxalate Potassium oxalate
Volume in cc. Amount of of X[ro K b l n 0 4 oxalate oxidised required for in terms of volthe oxalate left ume in cc. of after the exK / I O KMnO, perimen t
Percentage amount of oxalate oxidised
15.4
13.05
2.35
15.2
15.4
IO.8*
4.6*
29.8*
* In this experiment,
the intensity of light used was much greater than that used in the first experiment, thus showing greater amount of oxidation with increase in the intensity of light.
It is well-known that oxalate ion, C204”,is photosensitive and we have proved that it can be oxidised by passing air in presence of sunlight. TABLE V (A) I n each of these experiments, the volume of air passed was 36.5 litres in 53 hours. The weight of zinc oxide taken was exactly 0.5 grms. No. of Experiment I 2
3 4
5 6 7 8 9 IO I1 I2
I3 I4
Substance used in the experiment
Arabinose Galactose Glucose Laevulose Cane sugar Lactose Maltose Starch Glycogen Glycine a-Alanine Hippuric acid Sodium urate Urea
Amount of Actual weight of substance in I O cc. substance of the solution oxidised in grm. taken in grm. (Blank)
Percentage amount of substance oxidised
0 .I0000
0.01IO
11.0
0.0861 0.0962 0,09185 0.0969 0.0997
0.0101
11.7
0.0114
11.8
0.0117
12.7
0.0128 0.0402 0.0454 0.0688 0.0382 0.0452 0.0481 0.0206
41.9 41.3 66.9 38.7 45.2 48.2 41.8
0.0037
22.5
0.0200
10.0
0 .I097
0.1027
0.0987 0’0999 0.0997 0.0492 0.I 5 7 5 0,2000
13.2
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OXIDATION BY AIR I N PRESESCE O F SL-NLIGHT
In a recent paper we have proved that zinc oxide is a powerful photochemical sensitiser and many photochemical reactions have been accelerated by the presence of zinc oxide. We have carried on experiments on the oxidation of carbohydrates, glycogen, nitrogenous substances, and facts in sunlight in presence of zinc oxide. The results obtained are given in Table V.
TABLE F’ (B) Experiments with fats. Weight of zinc oxide taken was 0.5 grms. I O cc. of IC13 I O cc. of 107~ K I = 16.0 cc. of X/IO sodium thiosulphate
+
S o . of Experiment
I
2
3
Substance used in the experiment
Volume in cc. of N/IOsodium thiosulphate required for I O cc. of fat taken. (Blank)
Potassium stearate Potassium oleate Potassium palmitate
Volume in cc. of S/IO sodium thiosulphate required for the fat left after the experiment
15.25
15.60
10.45
12.4
13.55
14.55
Percentage amount of fat oxidised
46.6 35.1 40.8
TABLE V (C) Experiment with potassium oxalate. ZnO = 0.5 grm. I O cc. of potassium oxalate E 10.8cc. of 3/10 KMnOI S o . of Substance Experi- used in the ment experiment
I
Potassium oxalate
Volume in cc. of N/IO KMnO, required for I O cc. of potassium oxalate solution taken (Blank)
10.8
Volume in cc. of N/IO KMnOr required for oxalate left after the experiment
7.3
Amount of Percentage oxalate oldamount of dised in terms oxalate of volume in oxidised cc. of ?;/IO KMnO,
3.5
32.4
The foregoing experimental results show that the amount of oxidation is greater in presence of zinc oxide, which acts as a photosensitiser. Sunlight and artificial lights have been used with great success in the treatment of tuberculosis, pernicious anaemia, rickets, etc. In some previous publications1 we have emphasised the importance of sunlight in the treatment of deficiency diseases and we have observed that rickets, osteomalcia, beri-beri, pellagra, etc. would have been more common in poor tropical countries like India and China, had not the compensating agent, sunlight, been present. This conclusion has been corroborated by some experiments carried on in these laboratories. Two lots of pigeons were fed on polished rice for about six months. One lot had plenty of sunlight whilst the other had very little of it. The lot which had sunshine did not show any signs of polyneuritis whilst the other lot not having sunshine had stomachic troubles first and then showed definite signs of polyneuritis. Dhar: Chemie der Zelle und Gewebe, 12, 217,225, 317 (1925);13, 209
(1926)
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C . C. PALIT A S D N. R . DHAR
We are of the opinion that in the presence of sunlight the metabolism of the food materials taken in the system is accelerated and that is how disease is avoided. We believe that by absorption of sunlight the body cells are activated and greater amounts of oxidation of carbohydrates, fats and proteins take place than in the absence of sunlight. It seems pretty generally accepted that several diseases are caused by defective metabolism. We are of opinion that in these diseases, which are caused by the want of proper metabolism, sunlight or artificial light should be highly efficacious, because as we have proved experimentally the oxidation of fats, carbohydrates and nitrogenous matter is greatly accelerated by light. Summary and Conclusion Solutions of galactose, arabinose, cane sugar, glucose, laevulose, lactose, maltose, starch, glycogen, urea, glycine, a-alanine, hippuric acid, sodium urate, potassium stearate, potassium oleate, potassium palmitate, and potassium oxalate have been oxidised by passing air in presence of sunlight. 2. It has been found that the greater the intensity of sunlight, the greater is the amount of oxidation. 3 . Zinc oxide acts as a powerful photo-sensitiser in the above oxidations and in its presence the amount of oxidation in each case is greater than in its absence. 4. It is probable that by the absorption of sunlight, the cells in the animal body are activated and this activation leads to a greater amount of oxidation of fats, carbohydrates and proteins. Hence sunlight and other kinds of artificial lights prove efficacious in the treatment of diseases specially of metabolic origin. I.
Chemzcal Laboratory, AUahabad b'naverszty, Allahabad, Indaa. June, 1927
