Study on the Chemical Composition and Cytotoxic Activity of the Stem of Niujiaogua
Calotropis gigantea (L.) Dry. ex Ait f. Also known as the Broken Intestine Grass or the Five Dog Lying Flower Heart, it is a plant of the Calotropis genus in the Asclepiadaceae family. It is mainly distributed in parts of China, India, Vietnam, Sri Lanka, and Myanmar, as well as in Yunnan, Hainan, Guangdong, and Sichuan provinces of China. It grows on low altitude sunny slopes, open fields, and beaches. Niujiaogua has the effects of dispelling phlegm, relieving asthma, antibacterial, antioxidant, anti-inflammatory, and detoxifying. Bullhorn melon flowers have analgesic effects; Stem has a hepatoprotective effect; Leaves have anti diarrheal effects; Milk has the effects of promoting wound healing and antibacterial properties. Modern research has shown that croissants contain various chemical components, including cardiac glycosides, steroids, triterpenoids, and flavonoids. Due to its significant anti-tumor activity, many scholars have isolated, purified, and structurally identified the chemical components of cowpea. In order to better study the chemical basis of the Niujiaogua plant and further improve its biological activity, this study investigated the chemical composition and cytotoxic activity of Niujiaogua stem. Various chromatographic separation techniques such as silica gel and Sephadex LH-20 were used to separate the ethyl acetate fraction of the ethanol extract of Niujiaogua stem, and the in vitro cytotoxic activity of the compound against four types of tumor cells was determined by MTT assay.

Ten compounds were isolated from the stem of the horned gourd, with compounds 1, 3, 4, and 6-8 being the first isolated from this plant. Among them, compounds 1-4 are lignans and compounds 8-10 are phenolic compounds. The cytotoxic activity of compounds 1-10 against four types of tumors was tested, and the results showed that compounds 4 and 5 had varying degrees of cytotoxic activity against the four types of tumor cells, with IC50 values ranging from 12.37 to 49.29 and 0.29 to 0.98 μ M, respectively. Other compounds did not show significant activity. According to literature reports, compound 4 has weak cytotoxic activity against human ovarian cancer cell line SK-OV-3. Compound 5, Fructoside, is the main cardiac glycoside component in horned gourd, accounting for more than 2.8% of the extract content, and has strong cytotoxic activity against various tumor cells. Recent studies have shown that Fructoside can induce mitochondrial mediated apoptosis in melanoma cells, which may help prevent melanoma. This suggests that the compound may have many potential activities that have not yet been developed and have value for further research.