Die Nahrung 35 (1991) 4,369-371

institute of Nutrition and Food Hygiene, Havana, Cuba (Director: Dr. Milsa Cohas)

Antimutagenic activity of lettuce and chard extracts

A. Pkrez and G. Gago

The ability of lettuce and chard extracts to reduce the mutagenic activity of Benzo[a]pyrene was studied. In this experiment several groups of male Balb/C mice were treated with different doses of the substances under study. B[a]p was administered at doses of 36 and 72 mg/kg of body weight to groups I1 and 111, respectively. The lettuce extract combined with the doses of B[a]p were administered to groups IV and V. The experiment was performed again under the same conditions to test the effect of chard extract. Urine samples were tested by means of the Ames assay. The results show that the mutagenic activity of the urine samples from groups treated with B[a]p was reduced when the treatment also included any vegetable extract.

Introduction

In spite of the efforts directed to find and remove many substances representing a risk to human health, human beings are exposed to a great variety of them. One of the most potent carcinogens and mutagens widely expended in our environment is B[a]p, which has been identified at high levels in foodstuff [ 1l.Taking into account the impossibility to remove B[a]p and many other mutagens/carcinogens from our environment, new strategies began to develop in the recent past, for instance, the study of antimutagens and their mechanisms of action. Vegetables are considered important modulators of deleterious processes, the chloro- phyll content is suggested as playing an active role in their antimutagenic effect [2].

This paper demonstrates the ability of lettuce and chard extracts in reducing the excretion of mutagenic metabolites of B[a]p in mice.

Material and methods

The vegetables employed were lettuce and chard, obtained from a local market. The extracts were prepared and their chlorophyll level analysed according to the method proposed hy AOAC [3]. The extracts were con- centrated at 59 O C to a volume where each ml contained 7.2 mg chlorophyll.

Groups of 5 male Balb/C mice were used as experimental animals. Each animal received the test substan- ces by gastric intubation, according to the experimental design presented in Table I.

Urine samples from 24 h were collected during 3 days and rapidly frozen at -20 OC until the mutagenicity assay was performed. The Ames test was employed, TA 98 was the tester strain, combined with 500 U R-glu- curonidase per plate and 50, 100 or 200 pl urine.

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Die Nahrung 35 (1991) 4

Table 1 Experimental procedure (B[a]p** dissolved in DMSO)*

Group

~

I 11 In IV V

Thesamedr

tract** *

ign was used to test the effect of both vegetable extracts ** mglkg of body weight *** mg chlorophyll/kg of body weight

lefluce Extract

-

20

0 I m m P

Chard Extract

Fig. 1 By thc urine samples induced

rn sop1 m 100,iIl a 20ofli revertants

Perez / Gago: Antimutagenic activity 371

Results and discussion.

Fig.1 shows the induced revertants per plate by the urine samples. It can be observed that the number of induced revertants by urine samples from groups treated only with B[a]p (11, 111) is reduced to the control reversion (group I) by urine samples from groups treated also with one of the vegetable extracts (IV, V) suggesting an antimutagenic effect of both ex- tracts.

Chlorophyll has been assumed to be the active factor in the antimutagenicity of vegeta- bles [4, 51. These results could be determined in part by this substance, although antimuta- gens different from chlorophyll could be present in the extracts. Many of the known antimu- tagens, mainly vitamins, exhibit undesirable effects, however chlorophyll is ubiquitous in plants and is not known to be toxic [2].

Taking into account the relationship between mutagenicity and carcinogenicity [6], the antimutagenic agents should play an important role in the modulation of cancer, hence it is important to establish accurately the antimutagenic potency of vegetables and to deduce die- tary recommendations.

Zusammenfassung

A. Perez und G. Gago: Andmutagcnc Aktivitlt von Kopfsalat und Mangoidcxlraktcn Es wurde die FIhigkeit von Kopfsalat- und Mangoldextraitten zur Reduiierung der muVagcnen Aktivitlt

von Benzo(a]pyren untersucht. Dazu wurdcn mehrcrc Gruppcn mlnnlichcr Balh/C- Mlusc mit untcrschiedli- chen Dosen der Extrakte hchandelt. B[a]p wurde in Doscn von 36 hzw. 72 rng/kg KArpcmnasse an die Grup- pen I1 und 111 verabfolgt. Salatextrakte zusammen mit den hcidcn B[a]p-Dosen erhiclten die Gruppen IV und V. Entsprechende Vcnuche wurden zur Tcstung dcr Wirkung von Mangoldextrakt durchgcfiihrt. Zur Untcr- suchung der Urinproben wurde der Arnes-Test hcrange7ogen. Die Ergchnissc zcigcn, dal3 dic mutagenc Akti- vital der Gruppen, dcnen B[a]p verahfolgt wordcn war, redu7icrt wurde, wenn sic gleichzeitig eincn dcr pflanzlichen Extrakte erhalten hatten.

References

[l J Vaesscn,H.A.M.G., A.A. Jekcl and A.A.M.M. Wilhcrs, Toxicol. Environmcntal Chcm. 16, 281 (1988) [2] bi ,C.N. , Nutr. cancer 1, 19 (1988). [3] AOAC, 13 th ed., p. 49 (1980). [4] h i , C.N., M.A. Butler and T.S. Matney, Mutation Res. 77,245 (19x0). [5] Ohyama,S., S. Kitamori, H. Kawano, T. Yamada, T. Inamasu, M. Ishizawa and N. Ishinishi,

Mutation Res. 192,7 (1987). [6] McCann, J., E. Choi, E. Yamasaki and B.N. Ames, Roc. Natl. Acad. Sci. USA 72,5135 (1975).

A. Perez and G. Gago, Imlitute of Nutrition and Food Hygiene, Infanta 1158, Havana 3, Cuha.

Received June 5, 1990