Calycindaphines A-J, Daphniphyllum alkaloids from the roots of Daphniphyllum calycinum.

Ji Yang,Zhi-Hong Jiang,Jing Fu,Guo-Yuan Zhu,Xin Liu,Hao-Yuan Lyu,Li-Ping Bai

doi:10.1039/d1ra00107h

Abstract

Ten new Daphniphyllum alkaloids, calycindaphines A–J (1–10), together with seventeen known alkaloids were isolated from the roots of Daphniphyllum calycinum. Their structures were established by extensive spectroscopic methods and compared with data from literature. Compound 1 is a novel alkaloid with a new rearrangement C22 skeleton with the 5/8/7/5/5 ring system. Compound 2 represents the second example of calyciphylline G-type alkaloids. Compound 10 is the first example of secodaphniphylline-type alkaloid absent of the oxygen-bridge between C-25/C-29. The possible biogenetic pathways of 1 and 2 were also proposed. All the isolated compounds were evaluated for their bioactivities in three cell models. Compounds 22, 23, and 26 showed significant NF-κB transcriptional inhibitory activity at a concentration of 50 μM. Compounds 16 and 18 exhibited significant TGF-β inhibitory activity in HepG2 cells. Compounds 24 and 26 induced autophagic puncta and mediated the autophagic marker LC3-II conversion in HEK293 cells.

Highlights

The Daphniphyllum alkaloids were characteristically distributed in plants of the Daphniphyllum family.1–4 To date, more than 200 Daphniphyllum alkaloids with nearly 20 skeletons have been isolated from ten species
Previous phytochemical investigations on the leaves and stems of D. calycinum led to the isolation of more than 50 Daphniphyllum alkaloids with 15 different skeletons
Ten new Daphniphyllum alkaloids, calycindaphines A–J [1,2,3,4,5,6,7,8,9,10], together with 17 known alkaloids were isolated from the roots of D. calycinum

Summary

Introduction

The Daphniphyllum alkaloids were characteristically distributed in plants of the Daphniphyllum family.1–4 To date, more than 200 Daphniphyllum alkaloids with nearly 20 skeletons have been isolated from ten species. Compound 1, a white amorphous powder, has a molecular formula of C23H31O3N as established by its HRESIMS data (m/z 370.2375 [M + H]+, calcd for 370.2377), with 9 degrees of unsaturation.

Results

Conclusion