Within-plant distribution of coumarins in Coronilla and Securigera species

The within-plant distribution of the coumarin compounds was investigated in Coronilla (C. vaginalis Lam., C. scorpioides (L.) Koch, C. viminalis Salisb.) and Securigera (S. varia (L.) Lassen) species with regard to improving the extraction procedure allowing better furocoumarin recovery. The hydroxycoumarins umbelliferone, scopoletin, and daphnoretin, the dihydrofurocoumarin marmesin, and the furocoumarin psoralen were detected. The hydroxycoumarins umbelliferone, scopoletin, and daphnoretin were found in all investigated species although they were not present in all the different plant organs. The dihydrofurocoumarin marmesin, never previously detected in vivo in the genus Coronilla, occurs, only in the bound form, in leaves and roots of both C. scorpioides and C. vaginalis. Also in these two species the furocoumarin psoralen was detected in all the plant parts in both free and bound forms. On the contrary, the biosynthetic pathway of furocoumarin is not operative in C. viminalis and in S. varia. The preliminary acid hydrolysis of the plant material allowed psoralen recoveries substantially higher than the simple methanolic extraction, showing that in C. scorpioides and C. vaginalis the bulk of tire psoralen occurs in the bound form. With regards to the total psoralen contents, C. scorpioides appears to be a better natural source of this furocoumarin.