Quality evaluation and quantification of cucurbitacin E in different cultivars of Cucumis sativus L. fruit by a validated high-performance thin-layer chromatography method

Cucumis sativus L. of the Cucurbitaceae family, commonly known as cucumber, is commercially cultivated worldwide. The major phytoconstituents present in the Cucurbitaceae family are different curcurbitacins, principally cucurbitacin E. The content of cucurbitacin E differs within the species or cultivars due to factors like genetic variation and geographical location. The present study reports a simple and rapid quantitative analysis of cucurbitacin E in 5 different C. sativus cultivars by a validated high-performance thin-layer chromatography (HPTLC) method. The mobile phase contained petroleum ether, ethyl acetate and formic acid in the ratio of 40:60:0.5 (V/V). Cucurbitacin E was analyzed densitometrically and the absorbance wavelength was 254 nm. The method showed R_F spot = 0.79 ± 0.06, corresponding to cucurbitacin E in various samples. The calibration curve of standard cucurbitacin E showed good linear relationship in the concentration range of 2‒10 µg/spot with a correlation coefficient (r) > 0.99. The HPTLC method was validated in terms of sensitivity, linearity, accuracy, precision, and specificity as per the International Conference on Harmonization (ICH) guidelines. The present study revealed that the content of cucurbitacin E differs among the C. sativus cultivars. This method may be beneficial for addressing the quality-related aspects of C. sativus for food and pharmaceutical preparation.