Triterpenoid p-aminobenzoates from the seeds of zucchini.

An investigation of the triterpenoid fraction of zucchini seeds afforded two novel multiflorane p-aminobenzoates, identified as 7-epi zucchini factor A and debenzoyl zucchini factor B. Multiflorane p-aminobenzoates could not be detected in zucchini sprouts, which contained bryonolic acid as the only multiflorane constituent. No compound of this type could be obtained from adult plant parts (roots, stems, leaves).

Polycyclic diterpenoids from Euphorbia characias.

In addition to widespread flavonoids, a collection of Euphorbia characias from Sardinia afforded 13 oxygenated diterpenoids of the atisane, abietane, pimarane, and kaurane type. Four of these compounds (1, 3a, 7a,b) are new. The accumulation of substantial amounts of biologically active diterpenoids of limited availability, like ent-atisanes endowed with anti-HIV activity and ent-abietanolides active on the central nervous system, makes E. characias an interesting source of lead compounds for biomedical research.

Diterpenoids from euphorbia pithyusa subsp. cupanii

The aerial parts of Euphorbia pithyusa subsp. cupanii collected in Sardinia afforded eleven novel diterpenoids belonging to the lathyrane (1a), premyrsinane (4a-g), and tigliane (5a-c) types. Compounds 4a-g and 5a are esters of two new parent alcohols, named premyrsinol and 4,12,20-trideoxyphorbol, respectively. Structures were elucidated by spectroscopic and chemical methods. Puzzling differences between the NMR data of lathyrol (1c) and its esters were rationalized in terms of flipping of the exomethylene around the mean plane of the macrocycle.

Furohyperforin, a prenylated phloroglucinol from st. John's wort (Hypericumperforatum)

Furohyperforin, an oxygenated analogue of the prenylated phloroglucinol hyperforin, was isolated from the aerial parts of Hypericum perforatum. Its structure was elucidated as 2 on the basis of extensive NMR investigations.