New bioactive cyclopeptide alkaloids with rare terminal unit from the root bark of Ziziphus cambodiana.

Abstract

Six new 14-membered ring cyclopeptide alkaloids, cambodines A-F (1-6), and two known compounds, frangufoline (7) and lotusanine B (8), were isolated from the root bark extract of Ziziphus cambodiana Pierre. Their structures and configurations were established based on 1D and 2D NMR, HRMS, ECD, and X-ray crystallographic data. Compounds 1 and 3 are rare 5(14)-type cyclopeptide alkaloids that possess an imidazolidin-4-one ring in the terminal unit. The cyclopeptides were tested for their in vitro antiplasmodial, antitubercular, and cytotoxic effects against three cancer cell lines. Compound 3 showed significant antiplasmodial activity against the malarial parasite Plasmodium falciparum, with an IC50 value of 6.09 μM.

• Authors: Natthakaln Lomchoey, Panomwan Panseeta, Pornthip Boonsri, Nuttapon Apiratikul, Samran Prabpai, Palangpon Kongsaeree, Sunit Suksamrarn
• Journal: RSC advances (RSC Adv) Vol. 8 Issue 33 Pg. 18204-18215 (May 17 2018) ISSN: 2046-2069 [Electronic] England
• PMID: 35541146 (Publication Type: Journal Article)
• Copyright: This journal is © The Royal Society of Chemistry.