EFFECT OF MARCHANTINS AND RELATED-COMPOUNDS ON 5-LIPOXYGENASE AND CYCLOOXYGENASE AND THEIR ANTIOXIDANT PROPERTIES - A STRUCTURE-ACTIVITY RELATIONSHIP STUDY
C. Schwartner et al., EFFECT OF MARCHANTINS AND RELATED-COMPOUNDS ON 5-LIPOXYGENASE AND CYCLOOXYGENASE AND THEIR ANTIOXIDANT PROPERTIES - A STRUCTURE-ACTIVITY RELATIONSHIP STUDY, Phytomedicine, 2(2), 1995, pp. 113-117
Marchantins and related compounds, isolated from different species of
liverworts, were investigated for their inhibitory potential on cycloo
xygenase (COX) and S-lipoxygenase 5-(LOX), the key enzymes of the arac
hidonic acid cascade, and additionally in a cell-free lipid-peroxidati
on system. The results were compared with rate constants obtained in p
ulse-radiolytic studies. All substances tested showed significant inhi
bitory COX and 5-LOX-activity. Marchantin B with two catechol moieties
, as in NDGA, exerted an enhanced inhibitory effect in all test system
s. The most active compound in the 5-LOX-test was Perrottetin D (IC50
= 0.66 mu M), which was also effective in the COX and lipid-peroxidati
on assay. While the rate constant determined by pulse radiolysis was r
ather low, EPR studies at elevated temperatures demonstrated for perro
tterin D the presence of a pyrogallol-type radical, generated by a fur
an-ring opening reaction. In conclusion, all compounds from liverworts
investigated possess significant antiinflammatory activities. The res
ults let us suggest that all these phenolic compounds can be considere
d as promising leads due to their strong radical scavenger potential.