Chemical constituents of Callistemon citrinus from Egypt and their antiausterity activity against PANC-1 human pancreatic cancer cell line. Issue 16 (15th August 2020)

• Record Type: Journal Article
• Authors: Tawila, Ahmed M.; Sun, Sijia; Kim, Min Jo; Omar, Ashraf M.; Dibwe, Dya Fita; Ueda, Jun-ya; Toyooka, Naoki; Awale, Suresh
• Is Part Of: Bioorganic & medicinal chemistry letters. Volume 30:Issue 16(2020)
• Publication Date: 2020-08-15
• Subjects: Callistemon citrinus -- Pancreatic cancer -- PANC-1 -- Antiausterity agent -- Preferential cytotoxicity -- Drug discovery; Bioorganic chemistry -- Periodicals; Pharmaceutical chemistry -- Periodicals; 572
• DOI: 10.1016/j.bmcl.2020.127352
• Languages: English
• ISSNs: 0960-894X

Abstract

Graphical abstract: Abstract: Human pancreatic cancer is resistant to almost all conventional chemotherapeutic agents. It is known to proliferate aggressively within hypovascular tumor microenvironment by exhibiting remarkable tolerance to nutrition starvation, a phenomenon termed as "austerity". Search for the new agents that eliminate the tolerance of cancer cells to nutrition starvation is a promising strategy in anticancer drug discovery. In this study, two new meroterpenoids named callistrilones O and P (1 and 2 ) together with eight known triterpenes (3 –10 ) were isolated from the active dichloromethane extract of Callistemon citrinus leaves. The structure elucidation of the new compounds was achieved by HRFABMS, 1D, 2D NMR, and ECD quantum calculations. All isolated compounds were tested for their preferential cytotoxicity against PANC-1 human pancreatic cancer cells. Among these, callistrilone O (1 ) exhibited the most potent preferential cytotoxicity with a PC50 value of 0.3 nM, the strongest activity with over 2000 times potent than the positive control arctigenin. Callistrilone O (1 ) induced dramatic alterations in PANC-1 cell morphology leading to cell death under nutrient-deprived conditions. Compound 1 also inhibited PANC-1 cell migration and -PANC-1 colony formation under the nutrient-rich condition.