The Critically Endangered Bolivian Endemic Hieronymiella bedelarii (Amaryllidaceae): First Alkaloid Profile, Cholinesterase Inhibition, and Ex Situ Conservation Insights

Hieronymiella bedelarii is a Bolivian endemic species known from a single locality in Torotoro National Park and currently assessed as Critically Endangered on the IUCN Red List. Its alkaloid composition and cholinesterase-inhibitory activity have not previously been investigated. The GC–MS analysis identified eighteen alkaloids representing six structural types, with lycorine-, pretazettine- and homolycorine-type alkaloids being the most abundant groups. Bulbs of H. bedelarii yielded an alkaloid-enriched extract (0.80% w/w). Eight of the identified alkaloids are reported here for the first time in Hieronymiella, including candimine. Complementary UPLC–MS/MS analysis detected pretazettine and the artifact tazettine in the alkaloid-enriched extract. This extract showed stronger inhibition of acetylcholinesterase than butyrylcholinesterase, with IC50 values of 10.18 and 193.19 µg·mL−1, respectively. In a preliminary cultivation trial, 11 of 20 bulbils (55%) established and developed roots and leaves after 12 months under nursery conditions.