Two pairs of dihydrobenzophenanthridine alkaloid compounds in radix zanthoxyli as well as extraction method and application of two pairs of dihydrobenzophenanthridine alkaloid compounds

The invention belongs to the technical field of medicine extraction, and provides two pairs of dihydrobenzophenanthridine alkaloid compounds in radix zanthoxyli as well as an extraction method and application of the two pairs of dihydrobenzophenanthridine alkaloid compounds. The compounds are compounds as shown in formulas 1a, 1b, 2a and 2b or pharmaceutically acceptable salts thereof. The extraction method comprises the following steps: dissolving the shinyleaf pricklyash root extract in a tartaric acid solution, filtering, and extracting filtrate with ethyl acetate; combining the ethyl acetate extract and the acid water insoluble substance, and extracting with petroleum ether, ethyl acetate and n-butyl alcohol to obtain a petroleum ether part, an ethyl acetate part and an n-butyl alcohol part; performing silica gel column chromatography on the ethyl acetate part, collecting a target fraction, and separating the target fraction by using a reversed-phase chromatographic column, a sephadex column and a prepara