Composition of the essential oils of Pelargonium odoratissimum, P-exstipulatum, and P. x fragrans (Geraniaceae) and their bioactivity

The volatile oils of the leaves of two Pelargonium species, P. exstipulatum (Cav.) L'Herit. and P. odoratissimum (L.) L'Herit. (Geraniaceae) and a hyb rid, P. x fragrans, were obtained by steam distillation and the chemical co mponents were identified by capillary CC and GC-MS. Methyl eugenol was high in P. onorartvsirl-lurn and P. x fragrans fenchone and limonene was common in all three, whilst thujene and a-pinene were high in P. exstipulatum and P. fragrans, showing that the probable parents of the latter were P. exsti pulatum and P. odorotissimum. Pharmacological activity on smooth muscle in vitro showed that all three had a postsynaptic spasmolytic effect, which wa s mediated via cyclic AMP in P. odoratissimum and P. x fragrans. Microbiolo gical activity against Staphylococcus aureus, S. epidermidis, Proteus vulga ris and Bacillus cereus was similar for P. odoratissimum and P. x fragrans, and resembled that of commercial geranium oil. The results suggest that th ese essential oils could be used as relaxant agents in aromatherapy product s and as novel antimicrobial agents in food preservation or household produ cts. Copyright (C) 2000 John Wiley & Sons, Ltd.