Effect of glutathione S‐transferase (GST) M1 and T1 polymorphisms on lymphocyte DNA damage of Korean subclinical hypertensive patients after kale juice supplementation

Abstract

Glutathione S‐transferase (GST) forms a multigene family of phase II detoxification enzymes that are involved in the detoxification of xenobiotics by conjugating substances with glutathione. In this study, we examined whether supplementation of kale juice could modulate the levels of lymphocyte DNA damage in hypertensive patients, and whether this modulation could be affected by GSTM1 and T1 polymorphisms. Eighty‐four subclinical hypertensive patients showing systolic blood pressure (BP) over 130 mmHg or diastolic BP over 85 mmHg received 300 ml/day of kale juice for 6 weeks, and blood samples were drawn before and after the 6 weeks. DNA was extracted from whole blood samples, and GSTM1 and GSTT1 genotypes were determined using a multiplex PCR. Lymphocyte DNA damage was measured by comet assay and damage was quantified by measuring tail moment, tail length (μm), and DNA in tail (%). The level of DNA damage decreased significantly in both GSTM1‐null and GSTM1‐present genotypes (p<0.001) and decreased in both GSTT1‐null and GSTT1‐present genotypes after supplementation (p<0.001); however, after the 6‐week supplementation, the reduced effect of DNA damage was significantly greater in the GSTM1‐null genotype compared with the GSTM1‐present genotype. These results suggest that supplementation of kale juice might prevent lymphocyte DNA damage in subclinical hypertensive patients, and this preventive effect is affected by GSTM1 genotype (This research was supported by the Basic Science Research Program of the National Research Foundation of Korea (NRF) under the sponsorship of the Ministry of Education, Science and Technology (2010‐0012031)).