Anticancer Cardenolides from the aerial parts of Calortopis procera

Abstract

Column chromatography (CC) analysis of methanol and butanol extracts of the aerial parts of Calortopis procera as well as the methanol extract of its latex, led to the isolation of 8 cardenolides, of which the structures were elucidated by NMR and HRESIMS spectroscopy. They also revealed several triterpenes and flavonoid glycoside. Based on the antiproliferative activity reported for cardenolides, the activity of calotropin and calotoxin was tested against two common cancer cell lines, human triple-negative breast cancer cell line (MDA-MB-231) and human lung adenocarcinoma cell line (A549). The high toxicity of the latex also encouraged performing the same test on the same cancer cell lines. The anti-proliferative activity of calotropin and calotoxin was compared to the methanol extract and the wax of the latex. The results showed that calotropin and calotoxin have significant cytotoxicity against MDA-MB-231 and A549 cell lines ranging from 0.046 to 0.072 μM compared to the methanol extract and the wax of its latex ranging from 0.47 to 58.41 μM. Moreover, the results showed lower toxicity of all treatments to the human skin fibroblasts compared to the toxicity to both MDA-MB-231 and A549 cancer cells lines except the higher toxicity of Methanolic extracts of C. procera latex to the MDA-MB-231 cells. In conclusion, C. procera is a medicinal plant with a wide spectrum of cardinolides including calotropin and calotoxin, which are promising agents for targeted cancer phytotherapy.

An updated pharmacological insight into calotropin as a potential therapeutic agent in cancer

“…A recent study (Rascón Valenzuela et al, 2015a) indicated that the IC 50 values of calotropin on the same cell line are 0.0013 µM, while antiproliferative activity was confirmed on another two cancer cell lines LS 180 (human colorectal adenocarcinoma cell line) and PC-3 (human prostate cancer cell line) with IC 50 values 0.06 and 0.41 µM, respectively. Also, the cytotoxic effects of calotropin on lung adenocarcinoma A549 cells were confirmed in the research done by Sweidan et al (2021). Interestingly, they compared the effects of calotropin on human fibroblast cell lines as normal cells and the toxicity of calotropin was lower which indicated that calotropin is more selective to cancer cells compared to normal cells.…”