Cephalounei A, a New Cephalotaxus Alkaloid from the Powdered Stems of Cephalotaxus fortune Hook. f

Abstract

A new Cephalotaxus alkaloid, namely Cephalounei A (1), was isolated from the stems of Cephalotaxus fortune Hook. f. Their structures were elucidated by spectroscopic and mass-spectrometric analyses, including 1D-, 2D-NMR and HRESIMS. The relative and absolute stereochemistry of 1 was determined by a combination of NOESY correlations and electronic circular dichroism (ECD) spectra, respectively. The cytotoxicity of all compounds were evaluated against five cancer cell lines.

Cytotoxic alkaloids from the twigs and leaves of Cephalotaxus sinensis

“…Cephalosine H ( 8 ) was obtained as a white amorphous powder with a molecular formula of C 19 H 25 NO 4 from its HRESIMS ( m / z 332.1865 [M + H] + , calcd for C 19 H 26 NO 4 ,332.1862) and 13 C NMR data. The NMR data of 8 (Tables 2 and 4) were similar to those of cephalounei A, 21 except for the presence of an additional methoxy group ( δ H 3.81, 3H, s; δ C 56.5) in 8 and the absence of a methylenedioxy moiety ( δ H 5.89, 1H, s; 5.88, 1H, s; δ C 102.4) in cephalounei A. The additional methoxy group was located at C-16 based on the HMBC correlation from the methoxy group ( δ H 3.81) to C-16 ( δ C 147.6) and the NOESY correlation from the methoxy group ( δ H 3.81) to H-15 ( δ H 6.65).…”

“…The absolute configuration of 8 was elucidated to be the same as that of cephalounei A based on their similar ECD and optical rotation data. 21 Thus, the absolute configuration of 8 was assigned to be 2 R ,3 S ,6 S , and named cephalosine H.…”

“…In the present study, the twigs and leaves of C. sinensis collected from Qinling Mountains have been phytochemically investigated, leading to the isolation of twenty-one compounds (Fig. 1), including seven new cephalotaxine-type alkaloids (1)(2)(3)(4)(5)(6)(7) containing two pairs of enantiomers (1 and 2), one new cephalolancine-type alkaloid (8), four new homoerythrina-type alkaloids (9)(10)(11)(12), and nine known analogues (13)(14)(15)(16)(17)(18)(19)(20)(21). Herein, the isolation, structure determination, and cytotoxicity and SARS-CoV-2 3CL pro inhibitory activities of compounds 1-21 are described.…”