“…Taken together, celastrol should be a promising bioactive natural product for new drug discovery. However, unlike its relative triptolide, lots of total synthesis and structural modifications have conducted in the past two decades (Chen, Zhou, & Li, 2012; Hou, Liu, & Xu, 2019b; Kaloun et al., 2016; Liu et al., 2018; Ning et al., 2018; Patil et al., 2015; Wang et al., 2017; Xu, Chen, Tang, Feng, & Li, 2014; Xu et al., 2017; Xu & Liu, 2019; Xu, Tang, Feng, & Li, 2014a, 2014b; Xu, Tang, Yang, Feng, & Li, 2014; Zhang, Xiao, & Xu, 2019; Zhou, Yang, Ding, Li, & Miao, 2012), and some triptolide derivatives have already entered clinic for the treatment of challenging cancer and/or rheumatoid arthritis (RA) (Carter et al., 2012; Pao et al., 2019; Patil et al., 2012; Wang, Xu, Fu, Li, & Lou, 2012; Zhou et al., 2005). So far, there is only one total synthesis (Camelio, Johnson, & Siegel, 2015) and several chemical modifications of celastrol have been reported (Figueiredo, Salvador, Cortés, & Cascante, 2017a; Jiang et al., 2016; Kyriakou et al., 2018; Li et al., 2015, 2018; Pang, Luo, Liu, Wu, & Wang, 2018; Shan et al., 2017; Tang, Huang, Pan, Zhang, & Lu, 2015; Zhang, Zhang, Piao, & Quan, 2018; Zhu et al., 2017), which are largely focused on its anti‐cancer activity.…”