[Hydroxycinnamic acid esters in brassicaceous vegetables and garden cress].

The esters of caffeic, p-coumaric and ferulic acid with glucose or quinic acid and sinapoylglucose were determined in cauliflower, kale, Brussel sprouts, red, white, Savoy and Chinese cabbage and in garden cress by two different HPLC methods with gradient elution. In addition the occurrence of sinapin (sinapoylcholin) was checked. The pattern of hydroxycinamic acid esters in the Brassica species varied appreciably. In garden cress besides sinapin only sinapoylglucose was found. Sinapoylglucose is dominating in the group of glucose esters besides minor amounts of feruloylglucose. The 5-isomers of quinic acid esters, with neochlorogenic acid (5-caffeoylquinic acid) as the main compound, are dominating among the quinic acid esters. Considering the 3- and 4-isomers of quinic acid esters only 3- and 4-caffeoylquinic acids were determined in lower concentrations. Sinapoylquinic acid could never be recognized. Sinapin was determined in the Brassica species only in few cases in traces.