In plant-based medical systems, bitter
tasting plants play a key role in managing dyspepsia. Yet when it comes to
defining their mechanism of activity, herbalists and pharmacologists are split
between two theories: One involves cephalic elicited vagal responses while the
other comprises purely local responses. Recent studies indicate that bitters
elicit a range of cephalic responses which alter postprandial gastric phase
haemodynamics. Caffeine and regular coffee (Coffea arabica semen L.) increase
heart rate whereas gentian (Gentiana lutea radix, L.) and wormwood (Artemisia
absinthium herba L.) increase tonus in the vascular resistance vessels.
Following meals increased cardiac activity acts to support postprandial
hyperaemia and maintain systemic blood pressure. The increased vascular tonus
acts in parallel with the increased cardiac activity and in normal adults this
additional pressor effect results in a reduced cardiac workload. The vascular
response is a sympathetic reflex, evident after 5 minutes and dose dependent.
Thus gentian and wormwood elicit cephalic responses which facilitate rather
than stimulate digestive activity when postprandial hyperaemia is inadequate.
Encapsulated caffeine elicits cardiovascular responses indicating that
gastrointestinal bitter receptors are functionally active in humans. However,
neither encapsulated gentian nor wormwood elicited cardiovascular responses
during the gastric phase. These findings provide the platform for a new
evidence-based paradigm.
Author(s) Details
Michael K. McMullen
Life Force Research, Sweden.
Julie M. Whitehouse
Department of Life Sciences,
Faculty of Science and Technology, University of Westminster, London W1B 2HW,
UK.
Anthony Towell
Department of Psychology,
Faculty of Science and Technology, University of Westminster, London W1B 2HW,
UK.
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