Identification and Quantification of Cucurbitacins B and E in Different Parts of Bitter Gourd Plants Derived from Different Planting Methods

Abstract

Bitter gourd is a beneficial and easily accessible plant commonly utilised as a food source and medicinal herb. This plant produces numerous types of phytochemicals, especially when triggered by elicitors. It is also well known for its bitter taste, which is contributed by one of its phytochemical contents called cucurbitacin. This study determines the different levels of cucurbitacins B and E in the plants from two different planting methods, conventional and fertigation. Fruits, leaves, stems, and roots of bitter gourd plants from the two different planting methods were harvested for extraction using the sonication extraction method. The extraction solvents used were n-hexane, chloroform, and 80% ethanol. The extract’s cucurbitacins B and E content were identified and quantified using high-performance liquid chromatography. A preliminary rapid test using the Salkowski’s test to detect triterpenoids showed positive results for all sample runs. Results indicate significant variations in cucurbitacin levels across plant parts and cultivation methods. This study found that the content of cucurbitacin B in leaves of the fertigation planting method was the highest (208.0±0.4 ppm). Cucurbitacin B content in fruits was notably higher in both fertigation (200.0±1.3 ppm) and conventional (200.0±5.0 ppm) methods compared to other plant parts. However, leaves in the conventional method showed a significantly lower cucurbitacin B content (122.0±5.0 ppm). All plant parts were significantly different for cucurbitacin E, with the stem from the conventional planting method having the highest level of cucurbitacin E (31.0±1.0 ppm). Thus, it is concluded that plant parts and type of planting method can affect the cucurbitacin content in bitter gourd.