The HPLC analysis of the diethyl ether extract (Supplementary data, Figure 1S) revealed a major peak at Rt = 20.34 min that presents the TLC characteristics of the artifact-generating compound. After scaling-up to preparative HPLC, the compound of interest was isolated, and its purity verified by analytical HPLC (96.5% at UV 254 nm; Supplementary data, Figure 2S).