Antirotozoal effects of the Tomato Tetrasaccharide Glycoalkaloid Tomatine and the Aglycone Tomatidine on Mucosal Trichomonads

ORCID

Kirkwood M. Land: 0000-0001-5951-9630

Document Type

Article

Publication Title

Journal of Agricultural and Food Chemistry

Department

Biological Sciences

ISSN

Print: 0021-8561, Electronic: 1520-5118

Volume

64

Issue

46

DOI

10.1021/acs.jafc.6b04030

First Page

8806

Last Page

8810

Publication Date

11-11-2016

Abstract

The present study investigated the inhibitory effects of the commercial tetrasaccharide tomato glycoalkaloid tomatine and the aglycone tomatidine on three mucosal pathogenic protozoa that are reported to infect humans, cattle, and cats, respectively: Trichomonas vaginalis strain G3, Tritrichomonas foetus strain D1, and Tritrichomonas foetus strain C1. A preliminary screen showed that tomatine at 100 μM concentration completely inhibited the growth of all three trichomonads. In contrast, the inhibition of all three pathogens by tomatidine was much lower, suggesting the involvement of the lycotetraose carbohydrate side chain in the mechanism of inhibition. Midpoints of concentration–response sigmoid plots of tomatine on the three strains correspond to IC50 values, the concentration that inhibits 50% of growth of the pathogenic protozoa. The concentration data were used to calculate the IC50 values for G3, D1, and C1 of 7.9, 1.9, and 2.2 μM, respectively. The results show an approximately 4-fold variation from the lowest to the highest value (lowest activity). Although the inhibition by tomatine was not as effective as that of the medicinal drug metronidazole, the relatively low IC50 values for both T. vaginalis and T. foetus indicated tomatine as a possible natural alternative therapeutic for trichomoniasis in humans and food-producing (cattle and pigs) and domestic (cats) animals. Because tomatine has the potential to serve as a new antiprotozoan functional (medical) food, the distribution of this glycoalkaloid in tomatoes and suggestions for further research are discussed.

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