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

Figure 1

Inhibitory effects of plant essential oils on bacterial growth determined by colony forming units (CFU) assay. The individual bars show the number of surviving bacteria expressed as a percentage of control (, error bar = S.E.M). Differences in CFU in the control plate and CFU in each tested concentration of the oil or chlorhexidine (in the original dataset) statistically analyzed using independent Student’s -test: to 0.0001, compared with the control. The plant essential oil in-test concentration is in percentage of final assay volume. (a) Gram-negative bacteria: A. actinomycetemcomitans, P. gingivalis. (b) Gram-positive bacteria: S. mutans, L. acidophilus,and B. megaterium. Positive control: CHX = chlorhexidine. Plant species names: B.pi = Bidens pilosa; H.od = Helichrysum odoratissimum; V.am = Vernonia amygdalina; H.op = Hoslundia opposita; O.gr = Ocimum gratissimum; C.ci = Cymbopogon citratus; C.na = Cymbopogon nardus; T.no = Teclea nobilis Delile; Z.ch = Zanthoxylum chalybeum; L.tr = Lantana trifolia. Plant family names: (A) = Asteraceae; (L) = Lamiaceae; (P) = Poaceae; (R) = Rutaceae; (V) = Verbenaceae.