Cigarette Smoking and Depletion of Vitamin C. (UV Spectroscopic Study.)

Abstract
It is being pointed out that acetonitrile as one of the constituents of cigarette smoke and as a pollutant in the environment from many industries destroys one of the most important anti-oxidant (Vitamin C) of human system. The deficiency of Vitamin C has been related with many diseases. We have pointed out that the destruction of Vitamin C in the Human Respiratory tract by acetonitrile may aggravate coughing and secreting large amount of mucins which may further result in the deficiency of other very important anti-oxidants e.g., Vitamin E, present in epithelial lining fluid.
Key Words
UV spectroscopy, Smoking, Acetonitrile, Vitamin C, Respiratory tract, Human health
Introduction
“Smoking is injurious to health” in spite of this warning, the mankinds love for cigarette smoking has hardly diminished. Ayaori etal. [1]have listed lots of diseases with cigarette smoking and the efforts to educate public about its various harmful effects continue. While studying the anti-oxidant role of Vitamin C we have come across some very useful piece of observation which we feel may add to the pool of existing awareness. According to Erickson Cigarettes smoke is known to contain about 4700 chemical compounds, some of them are oxidants even highly carcinogenic [2]. We wish to point out about a particular chemical; acetonitrile, which has been identified as a part of cigarette smoke and one of the environment’s pollutant. Becker & Lowenheim etal. have reported that combustion of straw, wood and other vegetable produces acetonitrile and it is one of the byproduct of commercial synthesis of acrylonitrile .This means all acrylonitrile based paints consists acetonitrile as one of the major impurity and persons involved in painting may be seriously exposed to the inhalation of acetonitrile. It is reported by Dalhamn that 74% of inhaled acetonitrile is absorbed when smoke is held in the mouth for 2s (and not inhaled) whereas 91% is absorbed when the smoke is inhaled. The presence of acetonitrile in the body fluids of smokers have been identified while in the body of the non-smokers it is essentially absent [ AL Gross]. The quantity of acetonitrile in the urine have been suggested to be a better indicator of exposure of cigarette smoking rather than the number of cigarettes smoked. Baud etal have concludede that the presence of acetonitrile in the blood is a better marker than other tests. These observations clearly suggest that cigarette smoking injects acetonitrile in the human body. Cigarette smoke enters in the human body through respiratory tract. The major components of respiratory tract are epithelial cells, Respiratory tract lining fluids (RTLFs) etc. RTLFs are a heterogeneous group of substances covering epithelial cells from nasal mucosa to alveoli. Carroll and Cross identified that antioxidants and some other components of the system contained in RTLFs are expected to provide an initial defence against inhaled environmental toxins. One of the major antioxidant in RTLFs is Vitamin C. Several observations support an antioxidant role for ascorbic acid in RTLFs. Frei etal have found that the decreased systemic ascorbic acid levels and its increased turnover seen in cigarette smokers appear to be mainly caused by increased RTLF Vitamin C utilization subsequent to its oxidation by oxidants contained in the gas phase of cigarette smoke.
It is known that Vitamin C decomposes reversibly from ascorbic acid → ascorbate anion → dehydroascorbic acid in the body. All the constituents of this equilibrium play their defined role so long their level of concentration as defined by the equilibrium constant, is maintained. If the concentration level of dehydroascorbic acid increases to a very high level, it decomposes reversibly to oxalic acid and 2, 3 diketogulonic acid and thus the body is deprived of ascorbate anion and ascorbic acid. The high level of presence of oxalic acid chelates with calcium ions present in the body to form calcium oxalate (called stone).
Materials and methods. All the solvents used were either spectrograde quality or purified extensively before use. Vit.C purchased from E. Merck was recrystallised before use. UV spectra were recorded on Cary 100 UV-VIS spectrophotometer in closed 10 mm path length cells. Spectra with different batches were identical.
Results and Discussion
We have studied the decomposition of Vitamin C in acetonitrile through UV spectroscopy. The solution of Vit.C ( ~ 1.6 x 10-4 M ) in acetonitrile was allowed to decompose in the cavity of the spectrophotometer and gradual fall in the intensity was monitored over a period of time. Comparable amount of Vitamin C was allowed to decompose in acetonitrile and water. The decomposition was monitored by measuring absorbencies. It was observed that about 90% of Vitamin C decomposed in 1 hour in acetonitrile while in water even after 6 hours 20-25% of Vitamin C was still there.
Concentrated sulphuric acid was added to both the cells in the sample compartment to raise pH level to about 4.0. In the case of water a stable spectra due to ascorbic acid was restored immediately while in the case of acetonitrile no spectra either due to ascorbic acid or ascorbate was restored. The decomposition continued but with reduced rate. This indicates that decomposition of Vitamin C in acetonitrile is a function of the property of acetonitrile itself.
Conclusion
We conclude our observation that acetonitrile being a component of cigarette smoke and as pollutants in environment depletes the level of Vitamin C in RTLF. As a result of this deficiency the constituents of RTLF are not able to perform their role of anti-oxidant effectively e.g. May has pointed out that Vitamin C reduces a-tocopheroxyl radical to a-tocopherol (Vitamin E). Therefore the condition of people suffering from cough etc gets aggravated in the form of secretion of higher level of mucins which may result in the depletion of other anti-oxidant in RTLF and aggregation of inflammatory conditions of the respiratory tract.
Keynotes
The following point refers to the already known observations;
1. Acetonitrile is a constituent of cigarette smoke and environmental pollution.
2. Cigarette smoking is injurious to human health.
3. Vitamin C has been claimed to be one of the most important anti-oxidant of human system.
The following points add new observation;
1. Acetonitrile destroys Vitamin C irreversibly.
2. The deficiency of Vitamin C by acetonitrile in respiratory tract system may aggravates coughing.
3. Secretion of large amount of mucins during coughing may result in the deficiency of other anti-oxidant present in the respiratory epithelial lining fluid. This may create further complications in our respiratory tract system.

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