Eucophylline, a Tetracyclic Vinylquinoline Alkaloid from Leuconotis eugenifolius

Abstract

Eucophylline (1), a new tetracyclic vinylquinoline alkaloid, was isolated from the bark of Leuconotis eugenifolius together with leucophyllidine (2). The structure and absolute configuration of 1 were elucidated on the basis of 2D NMR correlations and simulated CD analysis. Leucophyllidine (2) showed iNOS inhibitory activity and decreased the iNOS protein expression dose-dependently.

Biologically active quinoline and quinazoline alkaloids part II

“…27), a new tetracyclic vinylquinoline alkaloid, were isolated from Leuconotis eugenifolius . 176 Leucophyllidine caused dose dependent inhibition of NO production stimulated by LPS (IC 50 7.1 μM), showed iNOS inhibitory activity, and decreased iNOS protein expression, while eucophylline was inactive. Both compounds showed high cell J774.1 viability at the above concentration.…”

“…Leucophyllidine caused dose‐dependent inhibition of NO production stimulated by LPS (IC 50 = 7.1 μM), showed iNOS inhibitory activity, and decreased iNOS protein expression, while eucophylline was inactive. Both compounds showed high cell J774.1 viability at the above concentration . In addition, the novel alkaloid scholarisine II ( 212 ) selectively inhibited COX‐2 and markedly inhibited 5‐LOX, while scholarisine I ( 213 ) (Figure ) with a vinyl rather than hydroxyethyl group did not …”

“…Both compounds showed high cell J774.1 viability at the above concentration. 175 In (Figure 27) with a vinyl rather than hydroxyethyl group did not. 176 The anti-inflammatory activity of tryptanthrin, a well-known indolo[2,1-b]quinazoline alkaloid, has been widely studied and was reported in our previous review.…”

“…Compounds 203 , 205 , 206 , and 210 showed moderate inhibitory effects on LPS‐induced NO production in BV2 cells (IC 50 < 10 μM), the remaining compounds had IC 50 values of over 10 μM. Leucophyllidine and eucophylline ( 211 ) (Figure ), a new tetracyclic vinylquinoline alkaloid, were isolated from Leuconotis eugenifolius . Leucophyllidine caused dose‐dependent inhibition of NO production stimulated by LPS (IC 50 = 7.1 μM), showed iNOS inhibitory activity, and decreased iNOS protein expression, while eucophylline was inactive.…”

Merging Gold Catalysis and Brønsted Acid Catalysis for the Synthesis of Tetrahydrobenzo[b][1,8]naphthyridines

“…Fused heterocyclic scaffolds such as tetrahydrobenzo[ b ][1,8]naphthyridine derivatives are of great biological and pharmaceutical value (Figure ) . For instance, bioactive species I and II are acetylcholine esterase inhibiting agent and mGlu1 antagonist respectively, while eucophylline III is an alkaloid isolated from Leuconotis eugenifolius . The potential bioactivity of these compounds has stimulated the efforts to construct the tetrahydrobenzo[ b ][1,8]naphthyridine cores.…”