After isolating the combined tertiary and quaternary bases, the water-soluble iodides were reduced by a published method. The obtained combined alkaloids were separated on a silica gel column, and a crystalline base (I) was isolated by elution with a chloroform-methanol mixture (97:3), with mp 163-164°C (benzene) and λethanol max 288 nm (log ε 3.57). The mass spectrum of base (I) showed peaks M+ 193, (M--1)+, (M--15)+, and a main peak (M--43)+ (characteristic for N-methyltetrahydroisoquinolines). Its NMR spectrum (CD3OD) exhibited signals of methoxy (3.75 ppm) and N-methyl (2.36 ppm) groups, two aromatic protons as singlets (6.59 and 6.4 ppm), and three methylene groups (a singlet at 3.41 ppm and a multiplet at 2.69 ppm). Methylation of (I) with diazomethane yielded an O-methyl ether. Based on these data, (I) was identified as 6-hydroxy-7-methoxy-N-methyl tetrahydroisoquinoline, which exists in the plant as a quaternary base (6-hydroxy-7-methoxy-N-methylisoquinoline or 6-hydroxy-7-methoxy-N-methyl-3,4-dihydroisoquinoline). Notably, isoquinolines of this type had not been previously isolated from the family Berberidaceae.