Three naphthalenic derivatives, four flavonoids and two of the four anthraquinones previously isolated
from the leaves of Rhamnus prinoides were successfully ionised under electrospray ionisation conditions.
These compounds were subsequently detected in the leaf extract of the plant using electrospray liquid
chromatography–mass spectrometry (LC–ESI–MS). The potential of LC–ESI–MS for screening a leaf
extract, with the focus on the suitability of the method for assaying the bitter principle, geshoidin, of this
commercially important plant, is presented.