Variation in glucosinolate and polyphenol level and level of peroxisome proliferator activated receptorγ (PPARγ) expression in an ethanol extract of Highland Kimchi cabbage

Variations of polyphenol and glucosinolate levels, and growth characteristics of 40 cultivars of Kimchi cabbage cultivated in highlands were analyzed, in combination with the level of peroxisome proliferator activated receptorγ (PPARγ) expression in ethanol extract from leaves. In addition, the effect of sulfur and nitrogen supply on the sulfur and glucosinolate content was investigated. Differences in the levels of total polyphenol and glucosinolate could be detected in the different cultivars of Kimchi cabbage. Glucosinolate epiprogoitrin was detected in small amounts or not detected, and the level of glucosinolate progoitrin showed clear-differences in different cultivars. The anti-carcinogenic glucosinolate gluconasturttin level in Kimchi cabbage (‘Asiaibssam’) leaves was higher than 6.85 μmol·g^-1. Sulfur and glucosinolate levels in Kimchi cabbage leaves were dependent on the sulfur supply. The levels of the aliphatic glucosinolates progoitrin, gluconapin and glucobrassicanapin generally decreased with the increase of nitrogen supply, but the indolyl glucosinolate glucobrassicin increased. The total polyphenol levels in Kimchi cabbage leaves ranged from 1.5 to 2.3 mg GAE/g. Leaf ethanol extracts of 40 cultivars of Kimchi cabbage cultivated in highlands, activated the expression of PPARγ 2-4 fold when compared with the negative control.