Abstrait

Compositions and comparison of the leaf and stem essential oils from Nigerian Hypoestes phyllostachya 'rosea' p. Beau. [Acanthaceae]

Dorcas Olufunke Moronkola, Odunayo Christy Atewolara- Odule, Oseyemi Omowunmi Olubomehin

Leaf and stem volatile oils were obtained differently from Hypoestes phyllostachya ‘Rosea’ [HR] [Acanthaceae] in 0.36% and 0.13% respectively. Fourteen main volatiles were identified in the stem part which had appreciable amount of sesquiterpenes with the most abundant compounds being 3,5,6,7,8,8a-hexahydro-4,8a-dimethyl-6-(1-methylethenyl)-2(1H) naphthalenone (38.01%), 1-ethenyl-1-methyl-2(1-methylethenyl)-4-(1- methylethylidene) cyclohexane (14.26%) and tetramethylcyclopropylidene methylbenzene(7.38%). Twenty-five compounds were identified in the leaf oil of HR which also contained appreciable amount of sesquiterpenes. The most abundant compounds were 3,5,6,7,8,8a-hexahydro-4,8a-dimethyl-6- (1-methylethenyl)-2(1H)naphthalenone(23.3%), and1-ethenyl-1-methyl-2- (1-methylethenyl)-4-(1-methylethylidene) cyclohexane(20.73%),whichwere the same as in the stem parts. The two most abundant compounds are common to both leaf and stem essential oils. They could be taken as taxonomic compounds for identifying HR, as well as being commercial sources of the naphthalenone and cyclohexane derivatives. The oils were characterised by the presence of derivatives of azulenes and naphthalenes. The known ubiquitous monoterpenes were absent in both leaf and stem essential oils. We report the volatile composition of Hypoestes phyllostachya ‘Rosea’ which is scarce in literature.