Alkaloids and flavonoids of Argemone mexicana.

A new protopine alkaloid, protomexicine and a new isoflavonoid, mexitin, together with 8-methoxydihydrosanguinarine, 13-oxoprotopine, rutin and quercetrin have been isolated from the aerial part of the methanolic extract of Argemone mexicana. The structures of these compounds have been established by various spectral data. The structure of protomexicine was further confirmed by heteronuclear multiple bond correlation experiment.

Quaternary alkaloids of Argemone mexicana.

Four quaternary isoquinoline alkaloids, dehydrocorydalmine, jatrorrhizine, columbamine, and oxyberberine, have been isolated from the whole plant of Argemone mexicana Linn. (Papaveraceae) and their structures established by spectral evidence. This is the first report of these alkaloids (dehydrocorydalmine, jatrorrhizine, columbamine, and oxyberberine) from Argemone mexicana and the Argemone genus.

Cyclopeptide alkaloids from Zizyphus sativa bark.

A new cyclopeptide alkaloid, sativanine-M (1), together with known alkaloid nummularine-P have been isolated from the stem bark of Zizyphus sativa and identified by spectral analysis.

Xylopyrine-A and xylopyrine-B, two new peptide alkaloids from Zizyphus xylopyra.

Two new 13-membered cyclopeptide alkaloids, xylopyrine-A and xylopyrine-B have been isolated from Zizyphus xylopyra, and their structures established by spectral and chemical evidences.