Identification and quantification of cucurbitacin in watermelon frost using molecular networking integrated with ultra‐high‐performance liquid chromatography‐tandem mass spectrometry

Abstract

Watermelon frost, a traditional Chinese medicine produced using watermelon and Glauber's salt, has been widely used for the therapy of oral and throat disorders. Watermelon contains various phytochemical compounds including cucurbitacins and their glycoside derivatives, which have attracted considerable attention because of their medicinal values. However, whether the composition of cucurbitacins existed in watermelon frost was rarely reported. In this study, three cucurbitacins including cucurbitacin B, isocucurbitacin B, and cucurbitacin E were found from watermelon frost extract assisted by ultra-highperformance liquid chromatography-tandem mass spectrometry and molecular networking guided strategy, and the compounds were verified using standard solutions. Furthermore, a quantification method for simultaneously targeted analysis of cucurbitacins was established using ultra-high-performance liquid chromatography-tandem mass spectrometry operating in the multiple reaction monitoring mode. Among them, cucurbitacin B and cucurbitacin E in watermelon frost samples were determined, and the concentrations were 3.78 ± 0.18 and 0.86 ± 0.19 ng/ml, respectively. While isocucurbitacin B was not detected due to the lower content possibly. In conclusion, ultra-high-performance liquid chromatography-tandem mass spectrometry combined with molecular networking is a very useful technique for the rapid identification of unknown cucurbitacin components in watermelon frost.

Total cucurbitacins from Herpetospermum pedunculosum pericarp do better than Hu-lu-su-pian (HLSP) in its safety and hepatoprotective efficacy

“…An UHPLC-Q-TOF MS system comprised of an AB SCIEX Triple-TOF 5600 + mass spectrometer (MA, United States) and a SCIEX Exion ultra-high performance liquid chromatography (UHPLC) system was used to conduct the LC-MS analysis ( Hu et al, 2023 ). LC separation was performed using a Phenomenex Kinetex ® Biphenyl C18 column (100 × 2.1 mm i.d., 2.6 m; Torrance, CA, United States) with a flow rate of 0.4 mL/min at 40°C.…”