DITERPENES FROM CHRYSOMA-PAUCIFLOSCULOSA - EFFECTS ON FLORIDA SANDHILL SPECIES

Th aerial parts of Chrysoma pauciflosculosa (syn. Solidago paucifloscu losa) gave the known diterpenes, 17-oxygrindelic acid, 17-oxogrindelic acid and 17-carboxygrindelic acid, as well as the new diterpene, 17-h ydroxy-7alpha,8alpha-epoxygrindelic acid. 17-Oxogrindelic acid decompo ses in the presence of air giving three products. The structural data of the diterpenes as well as those of degradation products and derivat ives were elucidated by chemical and spectroscopic methods. 17-Oxygrin delic acid and 17-oxogrindelic acid were tested for their effect on th e germination and radicle growth of three Florida sandhill species and Lactuca sativa. At concentrations of 12 to 48 ppm, 17-oxogrindelic ac id reduced the germination and radicle growth of Schizachyrium scopari um and Leptochloa dubia, two native sandhill grasses, but had no signi ficant effects on germination and only a slight stimulatory effect on radicle growth of Rudbeckia hirta and Lactuca sativa. Mixtures of 17-o xogrindelic acid with an equimolar mixture of three C. pauciflosculosa sesquiterpenes, (+)-curlone, (+)-sesquiphellandrene and (-)-alpha-tra ns-bergamontene, did not enhance activity. 17-Oxygrindelic acid was in general less active in reducing germination and growth than 17-oxogri ndelic acid.