23,24-Dihydrocucurbitacin C: a new compound regarded as the next metabolite of cucurbitacin C

Cucurbitacin C, a bitter substance in Cucumis sativus L., was isolated from green leaves by using phytochemical methods. An analytical method using high-performance liquid chromatography (HPLC) was established for the quantification of cucurbitacin C in different parts of the cucumber plant at different growth periods. Cucurbitacin C was detected in the leaves and stems but not in the female flowers, fruits, roots and leafstalks. The level of cucurbitacin C decreased significantly with the process of young leaves turning old. A new compound named 23,24-dihydrocucurbitacin C, regarded as the next metabolite of cucurbitacin C, was determined unambiguously by HPLC-quadrupole-time-of-flight mass spectrometry and nuclear magnetic resonance.