Is ascorbic acid a general detoxifying agent?

Chemosphere No. 2/3~ pp 129 - 132, 1977.

Pergamon Press.

Printed in Great Britain.

IS ASCORBICACID A GENERALDETOXIFYINGAGENT?

Aftab Ahmad, G. P. Semeluk and I. Unger Department of Chemistry University of New Brunswick P. O. Box 4400 Fredericton, N. B. E3B 5A3 (Received in UK for publication 7 January 1977)

That ascorbic acid is essential for human existence has been known since the pioneering work of Szent-Gyorgi I.

In recent years i t has become apparent

that ascorbic acid plays a much wider role and indeed may be a general detoxifying agent.

Thus Kevany, Jessop and Goldsmith2 have shown that ascorbic acid, in

man, converts cholesterol into bile acids.

Ascorbic acid i n h i b i t s the in vivo

formation of carcinogenic nitrosoamines 3'4.

Shomberger5 and co-workers have

demonstrated that ascorbic acid decreases the damage that 7,12-dimethyl benzanthracene does to chromosomes and various workers6'7 have shown that ascorbic acid can prevent the harmful effects of heavy metals.

Most recently

Carlson, Cable and Pederson8 have carried out theoretical calculations in support of the hypothesis that ascorbic acid is a general detoxifying agent. We have examined in v i t r o the effect of ascorbic acid on a number of common pesticides:

129

13o

No. 2/3

Cl CHCCI

DDT

,o~o-I-(OCH3)2

Fenitrothion

O-C-NHCH3 Meobal CH3

O-I-NHCH3 Matacil CH3~

N,,

CH~3 CH3 and

cH3~o-INHcH3 CH~ CH3

Landrin

~o. 2/3

131

Experiments were carried out in neutral and HCI acidified ethanol solutions at temperatures ranging from room temperature (~22°C) to 40°C. Ascorbic acid concentrations ranged from O.ll35xlO-4M to O.5677xlO-3M, concentrations of pesticide were adjusted to give the mole ratios l : l , pesticide to ascorbic acid.

1:2, 1:3, and 1:4 of

No decomposition of any pesticide was observed

under any of the experimental conditions, i . e . , in neutral or in acidified solution, at room or at elevated temperature, at any of the mole ratios noted, at any concentration used. Nor was there any spectroscopic evidence for any form of association between ascorbic acid and pesticide.

We did, however,

observe the disappearance of the ascorbic acid under a l l experimental conditions, presumably because of the well known oxidation reaction in non-deaerated solution. was

Control runs showed that the rate of disappearance of ascorbic acid

the same whether or not a pesticide was present.

These results indicate

that,at least in vitro,ascorbic acid is not a detoxifying agent for this group of pesticides.

The results are summarized in the table.

ACKNOWLEDGMENTS We are grateful to the National Research Council for their financial assistance.

132

~o. 2/3

Reaction Mixture

Ascorbic Acid Conc. XlO4 M

Pesticide Conco XlO4 M

Asc. Acid + DDT

1.362

0.449

Asc. Acid + DDT

1.135

0.564

Asc. Acid + DDT

1.135

1.128

Asc. Acid + Meobal

5.6775

5.585

Asc. Acid + Landrin

2.27

2.06

Asc. Acid + Matacil

0.1135

0.1152

For each reaction mixture four experiments were run, in neutral and acidified ethanol, at room temperature and at 40°C.

No dissociation of pesticide or

association with ascorbic acid was observed in any experiment.

REFERENCES: I.

A. Szent-Gyorgi, Soc. Chim. B i o l . , 15, 693 (1933).

2.

J. Kevany, W. Jessop and A. Goldsmith, Irish Jr. Med.Science.144,474(1975).

3.

S. S. Mirvish, et al:

4.

S. Ivankovic, et al:

5.

J. Shamberger, et al:

6.

I, V. Shcherbakova, CA., 61, 16691 g (1964).

Science 177, 65 (1972). Naturwissenschaften 60, 525 (1973). Proc.Nat.Acad.Sci., U.S.A., 70, 1461 (1973).

Sbornik Nauchn. Trudvov. Ryazansk: Med. Inst. 15, 190 (1962). 7.

Mo R. Spiveyfox and B. E. Fry, J r . , Science 169, 989 (1970).

8.

G. L. Carlson, H. Cable and L. G. Pederson,Chem. Phys. Letters, 38, 75 (1976).