| Chinese kale is an original Chinese vegetable which is high in nutrient value. Changes in glucosinolate profile of Chinese kale at different developmental stages, quinine reductase induction activity of edible parts among different Chinese kale varieties, and the effect of biotic stress (insect attack) on glucosinolate profile of Chinese kale seedlings were studied. The main results were as the following.An effective HPLC analytical method was developed for the analysis of glucosinolates. The glucosinolates profiles of in 13 Chinese kale cuitivars at different developmental stages were detected by HPLC analysis. The main aliphatic glucosinolates in Chinese kale were glucoraphanin and gluconapin, while the main indole glucosinolates in it were glucobrassicin, 4-metoxyglucobrassicin and neoglucobrassicin with glucobrassicin being the most abundant. No benzylic glucosinolate was detected in Chinese kale. Sulforaphane, the degradation produce of glucoraphanin is the most potent, naturally occurring, anticarcinogenic phytochemical identified thus far, it inhibits the development of cancer by specific modification of carcinogenic metabolism, induces the programmed cell death in human cancer cells, and therefore plays an important role in chemoprevention of cancer. The glucosinolate analysis showed that glucosinolate profile and content differed among different cuitivars, the glucoraphanin content of edible part differed among different cultivas, and glucoraphanin content was signifincantly high in edible part of Chinese kale cv. 'JL-SNZH'. The glucosinolate content of sprout was significantly higher than other stages, while the lowest glucosinolate content was observed at the stage of cotyledon. The extremely rich of glucoraphanin in sprout of Chinese kale cv. 'JL-FZHH' indicated the potential role of Chinese kale sprout in anticancer functional food. Chinese kale contained relatively less indole glucosinolates compare to aliphatic ones, the indole glucosinolate content of Chinese kale shifted among different varieties and at different stages, but the biological function of indole glucosinolate at different stages in Chinese kale remained to be further investigated.Effect of different extract methods, lysing solutions, and the incubation time of QR reaction mixtures on Quinone reductase bioassay was studied, and the results showed that the QR inducer potency of Chinese Kale phosphate buffer (5 mM K2HPO4-KH2PO4, 1 mM EDTA, pH 7.6) extracts was comparable to the potency of common triple solvent extracts. Extraction with phosphate buffer was better than other methods extraction with organic solvents because of its simplicity and effectiveness. 0.4% Nonidet P-40 can be substituted for 0.8% digitonin during cell lysis in QR assay. The suitable incubation time of QR reaction mixtures in QR assay was 5 to 10 minutes. The QR induction potency and activity of edible part of 13 Chinese kale cuitivars were analyzed, and the results showed that both the QR induction potency and activity of edible part of Chinese kale cv.'JL-SNZH' were significantly higher than other cuitivars, which was coincided with the significantly high content of glucoraphanin in the same cultivar.The survival of Bemisia tabaci of B biotype in Chinese kale and the changes of glucosinolates induced by biotic stress {Bemisia tabaci attack) were studied. The results showed that Bemisia tabaci could survive in all Chinese kales varieties tested, and there was no significant difference in survival rate among different Chinese kales cuitivars, while the amount of eggs per Bemisia tabaci were significantly less inChinese kale cv. 'JL-DFZC and 'JL-NPSJ'. Glucosinolate analysis of Chinese kale after Bemisia tabaci attack indicated that the total aliphatic glucosinolate content was significantly low in Chinese kale cv. "JL-TCLY", the total aliphatic glucosinolate content decreased steadily 12 h after Bemisia tabaci attack in all cultivars tested. The total indole glucosinolate content increased lh after Bemisia tabaci attack, being highest 12h after attack, and then decreased in all cultivars. The total indole glucosinolate content were significantly higher in Chineses kale cv. 'JL-DFZC and 'JL-NPSJ' than other cultivars 12h after attack, which was coincided with the low survival rate and significantly less eggs of Bemisia tabaci in these two Chinese kale cultivars. Furthermore,, an unknown glucosinolate was detected 3h after attack, the characteristic and function of the glucosinolate remained to be further investigated. |
