Essential Oils from Ugandan Aromatic Medicinal Plants: Chemical Composition and Growth Inhibitory Effects on Oral Pathogens

Abstract

The study assessed the growth inhibitory effects of essential oils extracted from ten Ugandan medicinal plants (Bidens pilosa, Helichrysum odoratissimum, Vernonia amygdalina, Hoslundia opposita, Ocimum gratissimum, Cymbopogon citratus, Cymbopogon nardus, Teclea nobilis, Zanthoxylum chalybeum,andLantana trifolia) used traditionally in the management of oral diseases against oral pathogens. Chemical compositions of the oils were explored by GC-MS. Inhibitory effects of the oils were assessed on periodontopathicPorphyromonas gingivalisandAggregatibacter actinomycetemcomitansand cariogenicStreptococcus mutansandLactobacillus acidophilususing broth dilution methods at concentrations of 1%, 0.1%, and 0.01%. The most sensitive organism wasA. actinomycetemcomitans. Its growth was markedly inhibited by six of the oils at all the concentrations tested. Essential oil fromC. nardusexhibited the highest activity with complete growth inhibition ofA. actinomycetemcomitansandP. gingivalisat all the three concentrations tested, the major constituents in the oil being mainly oxygenated sesquiterpenes. Most of the oils exhibited limited effects onL. acidophilus. We conclude that essential oils from the studied plants show marked growth inhibitory effects on periodontopathicA. actinomycetemcomitansandP. gingivalis, moderate effects on cariogenicS. mutans, and the least effect onL. acidophilus. The present study constitutes a basis for further investigations and development of certain oils into alternative antiplaque agents.