Fig. 1.

Purification and Identification of sterubin. (A) Fractionation of Yerba Santa extract by reversed phase HPLC. Conditions were similar to the ones described in Methods but a gradient from 9% to 90% acetonitrile within 30 min was employed. One minute fractions were collected. (B) Survival assay of HPLC fractions. HPLC fractions were dried in vacuo and reconstituted in DMSO before being tested in the oxytosis assay. (C) MS spectrum of active fraction. A major signal was detected at m/z = 303.09. Signals which were also present in the blank sample are labeled by an asterisk (*). (D) MS/MS spectrum of the isolated m/z = 303.09 signal. (E) MS/MS spectrum of pure sterubin recorded under the same conditions as for the natural material. The fragmentation pattern is essentially identical to one of the natural isolate. (F) MS/MS spectrum of synthetic homoeriodictyol recorded under the same conditions as for sterubin.