Norcolocynthenins A and B, two cucurbitane 3-nor-Triterpenoids from Citrullus colocynthis and their cytotoxicity

Yushuang Liu; Lu Zhang; Jingjing Xue; Kaibo Wang; Huiming Hua; Tao Yuan

doi:10.1016/j.bioorg.2020.104045

Norcolocynthenins A and B, two cucurbitane 3-nor-Triterpenoids from Citrullus colocynthis and their cytotoxicity

Bioorg Chem. 2020 Aug:101:104045. doi: 10.1016/j.bioorg.2020.104045. Epub 2020 Jun 25.

Authors

Yushuang Liu¹, Lu Zhang², Jingjing Xue³, Kaibo Wang⁴, Huiming Hua³, Tao Yuan⁵

Affiliations

¹ The Laboratory of Effective Substances of Jiangxi Genuine Medicinal Materials, College of Life Sciences, Jiangxi Normal University, Nanchang330022, China; The Key Laboratory of Plant Resources and Chemistry of Arid Zone, State Key Laboratory of Xinjiang Indigenous Medicinal Plants Resource Utilization, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011, China; Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, United States.
² The Laboratory of Effective Substances of Jiangxi Genuine Medicinal Materials, College of Life Sciences, Jiangxi Normal University, Nanchang330022, China.
³ Key Laboratory of Structure-Based Drug Design and Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China.
⁴ Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, United States.
⁵ The Laboratory of Effective Substances of Jiangxi Genuine Medicinal Materials, College of Life Sciences, Jiangxi Normal University, Nanchang330022, China; The Key Laboratory of Plant Resources and Chemistry of Arid Zone, State Key Laboratory of Xinjiang Indigenous Medicinal Plants Resource Utilization, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011, China. Electronic address: tyuan@jxnu.edu.cn.

PMID: 32629288
DOI: 10.1016/j.bioorg.2020.104045

Abstract

Two novel cucurbitane 3-nor-triterpenoids, named norcolocynthenins A (1) and B (2), were isolated from the fruits of Citrullus colocynthis. The structures including their absolute configurations were determined by extensive spectroscopic analyses and theoretical calculations. Compound 1 features an unprecedented 5/6/6/5-fused ring system while compound 2 possesses a rare lactone moiety at modified ring A. Compounds 1 and 2 showed significant cytotoxic activity against human cancer cell lines of HL-60 (IC₅₀ = 8.32, 6.49 μM) and PC-3 (IC₅₀ = 31.26, 13.42 μM). The plausible biosynthetic pathway of compounds 1 and 2 via a key enzymatic Baeyer-Villiger reaction is proposed.

Keywords: Citrullus colocynthis; Cucurbitane nortriterpenoid; Cytotoxicity; Theoretical calculations.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Citrullus colocynthis / chemistry*
Glycosides / chemistry*
Humans
Male
Molecular Structure
Rats
Rats, Sprague-Dawley
Triterpenes / chemistry*

Substances

Glycosides
Triterpenes
cucurbitane