Four new steroidal components from Smilacina henryi and their cytotoxic activities

Highlights

• Four new steroidal components and two known analogues were isolated from Smilacina henryi.

• Their structures were elucidated by spectroscopic analysis and chemical evidence.

• All compounds were tested their cytotoxic activity against human U87MG and HepG2 cancer cell lines.

Abstract

Four new steroidal components (1−4) along with two known analogues (5−6) were obtained from the roots and rhizomes of Smilacina henryi. The components’ structures were determined as (25S)-5α-spirost-9(11)-ene-3β, 17α, 21-triol (1), (24S, 25S)-5α-spirost-9(11)-ene-3β, 17α, 24-triol (2), (25S)-5α-spirost-9(11)-ene-3β, 17α-dihydroxy-12-one (3), 5α-cholest-9(11)-ene-3β, 26-dihydroxy-16, 22-dione (4), (25S)-5α-spirostan-9(11)-en-3β, 17α-diol (5), (25S)-5α-spirostan-9(11)-en-3β, 12β, 17α-triol (6) by physicochemical properties and spectroscopic methods. In addition, all of the compounds had their cytotoxic activities tested against U87MG and HepG2 tumour cells by the MTT method. Compounds 3 and 6 showed moderate inhibitory effects against the U87MG cells with IC₅₀ values of 15.5 μM and 27.2 μM, respectively, while compounds 1−6 showed different inhibitory effects against the HepG2 cells with IC₅₀ values of 9.8 to 56.3 μM, respectively.

Introduction

Smilacina henryi (Baker) F.T. Wang & T. Tang (S. henryi), a aperennial herb of the genus Smilacina (Liliaceae), is widely distributed in Shaanxi, Gansu, Yunnan, Hebei and Sichuan province in China (Cui et al., 2018; Zhang et al., 2013). As one of approximately 16 species grown in China (Yang et al., 2009), its roots and rhizomes are usually used as traditional Chinese medicines and have the ability of dispelling pathogenic wind, removing dampness, promoting blood circulation and alleviating pain and are typically used as folk medicine for the treatment of rheumatism, traumatic injury and impotence (Cui et al., 2018). In recent year studies, steroidal saponins (Liu et al., 2012; Zhang et al., 2006; Yang et al., 2009), sapogenins (Cui et al., 2018) and flavonoids (Zhang et al., 2006) with antitumour and antioxidant activities were obtained from the genus Smilacina, however, phytochemical and pharmacological investigation of S. henryi has been minimal, and to the best of our knowledge, with only one paper published on this topic (Zhang et al., 2013). This research aims at enriching knowledge of the chemical composition and its antitumour activity of the plant. In the present paper, we report the isolation and structure elucidation of four new and two known sapogenins by detailed spectroscopic analysis, including 1D, 2D NMR, IR, HR-ESI-MS and chemical methods, and their antitumour activities against U87MG and HepG2 cell lines are also described.