Procedure A: the dried powder was extracted with methanol/
acetic acid (100:1) at ratio 1:10 (w/v) overnight under agitation;
the extraction was repeated twice for 1 h. Extracts were combined
and evaporated under reduced pressure (40 8C). The residue was
solubilized in water/acetic acid (100:1), and washed thrice with
diethyl ether (1:1; v/v). The washing phase was evaporated (W1;
2.7% w/w). The aqueous phase was brought to pH 10 with
ammonia and extracted thrice with dichloromethane (1:1; v/v).
The organic phases were combined and evaporated under reduced
pressure to yield the alkaloid extract (Alk1; 1.9% w/w).