Geranium essential oil: standardisation, ISO; adulteration and its detection using GC, enantiomeric columns, toxicity and bioactivity

Abstract

The International Organisation for Standardization or ISO, defines Geranium oil as ‘The oil obtained by steam distillation of the fresh or slightly withered herbaceous parts of Pelargonium graveolens L’Heritier ex Aiton, Pelargonium roseum Willdenow and other undefined hybrids which have given rise to differing ecotypes in the various geographical areas’ (International standard 4731: 1972). The colour is various shades of amberyellow to greenish-yellow. The odour is given as characteristic of the origin, rose-like with a varying minty note. The specification does not include the Bulgarian Geranium oil distilled from Geranium macrorrhizum, known as Zdravetz oil, containing mainly sesquiterpenes of which half is apparently germacrone (Ognyanov, 1985). ISO 4731 has set the concentration for citronellol content at a minimum 42 per cent/maximum 55 per cent for Bourbon Geranium oil; 35/58 for Moroccan; 40/58 for Egyptian and 40/58 per cent for Chinese oils . Other physico-chemical values are given in Table 17.1.