Antifungal active ingredient from the twigs and leaves of Lour. Skeels (Rutaceae).

Two novel amides, named clauphenamides A and B, and twelve other known compounds were isolated from the twigs and leaves of Lour. Skeels (Rutaceae). Their structures were elucidated on the basis of extensive spectroscopic analysis and comparison with data reported in the literature. Clauphenamide A () featured in the unit of N-2-(4,8-dimethoxyfuro [2,3-b]quinolin-7-yl)vinyl, and clauphenamide B () was a unprecedented N-phenethyl cinnamide dimer. Other known compounds belong to pyrrolidone amides ( and ), furacoumarins (-), simple coumarins (-), lignan () and sesquiterpene (). Compounds , , and were separated from the genus () for the first time, while was isolated in the species () for the first time. The antifungal activities of the isolated compounds were assayed. As a result, at the concentration of 100 g/ml, compared with the control (chlorothalonil, inhibition rate of 83.67%), compounds and were found to exhibit moderate antifungal activity against with inhibition rates of 68.39% and 52.05%, respectively. Compounds - also exhibited moderate activity against and , with inhibition rates greater than 40%. In addition, compared with the control (chlorothalonil, inhibition rate of 69.02%), compounds - showed strong antifungal activity to , with inhibition rates greater than 55%. Among them, compound has the strongest antifungal activity against , and the inhibition rate (65.44%) is close to that of the control chlorothalonil. Additionally, the structure-activity relationships of the separated compounds are also discussed preliminarily in this paper.