From the epigeal part of the plant Haplophyllum leptomerum Lincz. et Vved. growing in the mountains of Babatag, Tadzhik SSR, which has not been studied previously, have been isolated β-sitosterol, the known alkaloids γ-fagarine, skimmianine, and N-methyl-2-phenyl-4-quinolone, and the new alkaloid leptomerine. On the basis of spectral characteristics, the structure of N-methyl-2-propyl-4-quinolone has been established for leptomerine. © 1986 Plenum Publishing Corporation.