Betaine distribution in the Labiatae

Seventy-nine species and three hybrids of Labiatae have been examined for the presence of betaines, which were isolated from and characterised for all the plants tested in six of the eight subfamilies (Ajugoideae, Teucrioideae, Viticoideae, Lamioideae, Pogostemonoideae and Scutellarioideae). However, unlike the Lamioideae, all species of which had relatively high betaine levels, those members tested of the other major subfamily, the Nepetoideae, either gave low betaine yields or these compounds were not detected. The three species examined representing the Chloanthoideae contained compounds which reacted with Dragendorff's reagent, but their structures could not be determined because of the small quantities isolated. The betaines found in different species of the same genus were very similar, supporting the view that these compounds have taxonomic significance at the generic level.