Ammi Visnaga (L.) Lam.: Occurrence of Khellin and Visnagin in Primary Rib Channels and Endosperm, and Emptiness of Vittae, Revealed by U.V. Microscopy*

Abstract

Sections of Ammi visnaga (L.) Lam. ripe fruits were examined by U.V. microscopy under U.V. 365 nm light and under mixed U.V. 365 nm and visible light. The examination revealed a substance with blue autofluorescence inside the primary rib channels; a blue colour was shown also by the endosperm, whilst vittae were empty. In sections extracted with a selective method for the furanochromones khellin and visnagin, the substance filling primary rib channels was completely dissolved, and the colour of endosperm faded. The extract was analysed by high-performance liquid chromatography: the solubilized materials were composed almost exclusively of khellin and visnagin. These data are in contrast with the previous consensus which considered coumarins and coumarin-like compounds to be located in the vittae of Umbelliferae fruits, and never present in endosperms, whilst primary rib channels were thought empty in ripe fruits.