Cucurbitacin

Cucurbitacins are bitter substances, which are found primarily in the gourd family and figworts ( Bacopa monnieri for example ).

Properties

A particular danger of poisoning is based on ornamental and wild gourds. By default, mutations or uncontrolled backcrossing of cultivated pumpkins with wild gourds the cucurbitacins can also cause serious, rarely fatal food poisoning.

The cytotoxic effect was tested experimentally as chemotherapeutic agent in cancer therapy. In addition, the effect of cucurbitacin has been demonstrated as an attractant selected from the group of the kairomones some beetle species as Diabrotica.

Chemically they belong to the group of tri- terpenoids with four ring closures ( tetracyclic triterpenes ), building on the basic structure of the Gonan. The 40 naturally occurring cucurbitacins and other synthetically altered are divided into 12 different classes, among other things, depending on its oxygenation. Well known are the cucurbitacins A to S and the Norcucurbitacine. Cucurbitacins can be glycosylated.

Among the cucumbers are numerous cultivars that differed in the presence or absence of cucurbitacin C. This has already been returned to early studies on a single diallelischen locus. In this case, the allele Bi leads ( for " bitter" ) to cucumber plants that are bitter under stress conditions and accumulate at the 300 mg / kg fresh weight. This applies both to the fruit, i.e. the cucumber, and the entire plant. Therefore, the ability to synthesize cucurbitacin C is determined already at the cotyledon stage. The allele bi ( " not bitter " for ) prevents this accumulation. At least in Central Europe - - market of non- bitter cucumbers destined Since this discovery in the late 1950s, the whole is to this day.