Polyhydroxy cucurbitane triterpenes from Hemsleya penxianensis tubers

Zhaocui Sun,Meigeng Hu,Guoxu Ma,Xiaowei Huo,Xiaolei Zhou,Zhonghao Sun,Xudong Xu,Nailiang Zhu,Junshan Yang

doi:10.1038/s41598-019-48365-0

Abstract

Ten new cucurbitane triterpenoids, hemsleyacins A–J (1–10), together with three known cucurbitane triterpenoids, dihydrocucurbitacin F (11), scandenogenin D (12), and jinfushanencin F (13), were separated from ethanolic tuber extracts of Hemsleya penxianensis. The absolute configurations of the new compounds were established based on NMR, HRESIMS, and CD spectra. Compounds 7 and 10–12 were evaluated in terms of their antifeedant activity against Plutella xylostella larvae. The result showed that compound 10 exhibited potent antifeedant activity against P. xylostella larvae after 48 h of treatment. Furthermore, the MTT test showed that compound 11 exhibited potent inhibition toward the UMUC-3 and T24 cell lines with IC50 values of 29.12 and 35.62 μM, respectively, compared to the positive control cisplatin IC50 values of 8.27 and 13.72 μM. Western blot analysis revealed that compound 11 treatments substantially inhibited the phosphorylation of IκBα.

Highlights

Different plant species contain unique secondary compounds that act as chemical defense against insects and other pathogens
To discover potential antifeeding products, we evaluated a 95% ethanol extract of H. penxianensis, obtaining 10 new cucurbitane-type triterpene hemsleyacins A–J [1,2,3,4,5,6,7,8,9,10] and three known cucurbitane-type triterpenes, namely, dihydrocucurbitacin F6 [11], scandenogenin D7 [12], and jinfushanencin F8 [13] (Fig. 1)
Their structures were elucidated based on an examination of their spectra using 600 MHz nuclear magnetic resonance (NMR) spectroscopy [1H and 13C-NMR, homonuclear correlation spectroscopy (COSY), heteronuclear single quantum coherence spectroscopy (HSQC), heteronuclear multiple bond correlation (HMBC), and nuclear overhauser spectroscopy (NOESY)], infrared radiation (IR), ultraviolet spectroscopy, mass spectrometry (MS), and circular dichroism (CD)

Summary

Introduction

Different plant species contain unique secondary compounds that act as chemical defense against insects and other pathogens. Compound 2 was isolated as a white powder and had the molecular formula C32H50O9 based on HR-ESIMS (m/z 601.3369, calculated for C32H50O9Na [M + Na]+, 601.3353).

Results

Conclusion