Lippia species share
various pharmacological activities
and are used in traditional cooking and medicine worldwide. Combined
chromatographic techniques such as column chromatography, high-performance
liquid chromatography, and countercurrent chromatography led to the
purification of two new antifungal phenylpropanoid glycosides, lippiarubelloside
A (1) and lippiarubelloside B (2), by bioactivity-directed
fractionation of an ethanol-soluble extract from Lippia rubella, in addition to the known active related compounds forsythoside
A (3), verbascoside (4), isoverbascoside
(5), and poliumoside (6). The structures
of compounds 1 and 2 were determined by
comparison of their NMR spectroscopic data with the prototype active
compound 4. Cryptococcus neoformans,
which causes opportunistic lung infections, was sensitive to compounds 1–6 in the concentration range of 15–125
μg/mL. A synergistic effect (FICindex = 0.5) between 3 and amphotericin B was demonstrated. The glycosylated flavonoids
pectolinarin (7), linarin (8), and siparunoside
(9) were also isolated.