**Shaojie Huo 1, Jichun Wu 1, Xicheng He 1, Lutai Pan <sup>2</sup> and Jiang Du 1,2,\***


Academic Editor: John C. D'Auria Received: 1 December 2018; Accepted: 19 December 2018; Published: 20 December 2018

**Abstract:** Two new steroidal alkaloids, named hookerianine A (**1**) and hookerianine B (**2**) were isolated from the stems and roots of *Sarcococca hookeriana* Baill., along with two known compounds, sarcorucinine G (**3**) and epipachysamine D (**4**). On the basis of spectroscopic methods and by comparison with literature data, their structures were determined. As well as X-ray crystallography was performed to confirm compound **4**. To identify novel antitumor inhibitors, all compounds were performed a CCK-8 assay against five human cancer cell lines SW480, SMMC-7721, PC3, MCF-7 and K562 in vitro. Compound **2** exhibited moderate cytotoxic activities to all cell lines with IC50 values in the range of 5.97–19.44 μM. Compound **3** was the most effective one against SW480 and K562 cell lines with IC50 values of 5.77 and 6.29 μM, respectively.

**Keywords:** Buxaceae; *Sarcococca hookeriana*; steroidal alkaloid; cytotoxicity
