Study On The Antitumor Constituents From The Roots Of Uvarla Calamistrata (Annonaceae)

Uvaria calamistrata Hance is a tropical tree, widely distributed in Hainan , Guangdon and Guangxi provinces of southern China. The chloroform-soluble extract of the roots of the plant growing in Hainan island exhibits significant antitumor activities. In order to discover new antitumor agents from plant source, U. calamistrata Hance were subjected to phytochemical studies. More than forty compounds were isolated from the active fractions and their structures were determined. These compounds belong to five classes of chemical structures: Annonaceous acetogenins (19 compounds), polyoxygenated cyclohexenes (20 compounds), organic acid (2 compounds) , sesquipternes (2 compounds) and alkaloid (1 compound).Among the cyclohexene isolated, uvacalols A-P were new compounds. Uvacalols A-L have a basic skeleton of 1-methylcyclohexene-1,6-ene, with benzoate attached in hydroxymethylene group and hydroxyl group, and/ or acetoxyl group, benzoyloxyl group, ethenoxyl group at 2-4 positions of cyclohexene ring. This subclass of polyoxygenated cyclohexene was first found in Uvaria genera. Compounds A-I with ee'aa' substituents from C-2 to C-5, have similar CD curves and same relative configurations. Uvacalols J-L with eee'e' substituents from C-1 to C-5, have other relative and absolute configurations. Uvacalols M-P have the basic skeleton of l-methylcyclohexene-5,6-ene. The known polyoxygenated cyclohexenes were grandifloracin-- a dimer of cyclohexene, zeylena, piperenol A and 1,6-desoxypipoxide which is considered as the precursor of all cyclohexenes in biogenesis pathway.Of nineteen Annonaceous acetogenins, eleven compounds were new. Calamistrins A-E were mono-tetrahydrofuran ring acetogenins, with two flanking hydroxyl groups and one isolated hydoxyl group. Calamistrin E was the only...