Xenophyllum poposum (Philippi) V. A. Funk

Abstract

Xenophyllum poposum (syn. Werneria poposa) is a cushion-forming creeping sub-shrub 3-5 cm tall with unpleasant smell, commonly known as poposa or pupusa and widely used in Andean traditional medicine to treat hypertension, altitude sickness (mountain sickness), hepatic diseases and digestive disorders such as intestinal inflammation, diarrhea, intestinal colic, rheumatism and indigestion. Mono- and sesquiterpenoids accompanied by benzofuran derivatives such as tremetone and 6-hydroxytremetone have been identified in its essential oil while p-hydroxyacetophenone and benzofuran derivatives, flavonoids, coumarins and diterpenoids were isolated from organic extracts of aerial parts. 4-Hydroxy-3-(isopenten-2-yl)-acetophenone (1) is by far the dominant component of the methanol extract along with minor amounts of 6-hydroxytremetone (2). The hypotensive effect of compounds 1 and 2 has been demonstrated in rats and mice. In addition to tremetone and 6-hydroxytremetone (2), several other essential oil components are also bioactive. Thus, T-cadinol (epi--cadinol) inhibits induced intestinal hypersecretion in mice and contractions of the isolated guinea pig ileum whilst T-cadinol and cadinol possess significant anti-inflammatory activity and inhibit nitric oxide production induced by lipopolisaccharides. All available information seems to support the uses of X. poposum in traditional medicine. Due to the presence of so many bioactive metabolites, strong effects should be expected after the consumption of this herb and, consequently, the amount consumed (dose) should be carefully controlled to avoid undesirable effects. It is desirable to conduct deeper research to chemically characterize this plant with precision and define quality parameters and chemotypes. Almost nothing is known on the water soluble metabolites of poposa and studies in this area are to be expected.