Biological Activity of Quinoline Alkaloids from Raulinoa echinata and X-ray Structure of Flindersiamine

Raulinoa is a monospecific genus and the species Raulinoa echinata Cowan (Rutaceae) is endemic in the Itajaí Valley, SC, Brazil. This perennial woody shrub is characterized by the presence of spines and has only been found in a short interval (1000 m) on the frequently inundated banks of Itajaí river in an approximate altitude of 100 m, showing a high degree of adaptation to the environment. We have recently reported the isolation and biological activities of some compounds of R. echinata. In continuation of our search for trypanocidal compounds and natural products to be used in the control of leaf-cutting ants, we have investigated the methanol extracts of stems and leaves of R. echinata leading to the isolation of typical rutaceous furoquinoline alkaloids: the widespread skimmianine (1), kokusaginine (2), maculine (3), flindersiamine (4) and also the quinolone derivatives: 2-nnonyl-4-quinolone (5), 1-methyl-2-n-nonyl-4-quinolone (6) and 1-methyl-2-phenyl-quinolone(7). Leaf-cutting ants are one of the most serious agricultural pests in South American countries and the biological control Biological Activity of Quinoline Alkaloids from Raulinoa echinata and X-ray Structure of Flindersiamine