Profiling of alkaloids and eremophilanes in miracle tea (Packera candidissima and P. bellidifolia) products.

Commercial preparations of the Mexican herbal drug known as "miracle tea" (Packera candidissima and P. bellidifolia) have been profiled qualitatively by HPLC and GC-MS. Eremophilanes (3-7) were the major components found in the hexane-soluble fraction, while pyrrolizidine alkaloids (PAs) were identified in the alkaloid extracts. The content of free PAs and their N-oxides was determined for a total of 22 samples, and the results showed that the amount of these hepatotoxic compounds (0.0005-0.94% free PAs; 0.0004-0.55% N-oxides), through the presence of retrorsine (1) and senesionine (2) as the main constituents, may reach toxic levels. Hexane-soluble extracts from commercial presentations (dried whole plants) of both species afforded neoadenostylone (3), 6-(2-methylbutanoyloxy)-9-oxo-1-(10)-furanoeremophilene (4), and epineoadenostylone (5), in addition to methyl-4-hydroxyphenylacetate (8) and methyl-2-(1-hydroxy-4-oxocyclohexyl)acetate (9). Also, epicacalone (6) and the new compound 2β-hydroxyneoadenostylone (7) were isolated from P. bellidifolia.