CHEMICAL CONSTITUENTS AND ANTIMICROBIAL ACTIVITY OF ESSENTIAL OILS FROM COSTUS LUCANUSIANUS J. BRAUN & K. SCHUM.

Adesegun O. Onanuga* and Ganiyat K. Oloyede

ABSTRACT

The essential oil of different organs of Costus lucanusianus J. Braun & K. Schum (Family Costaceae) obtained by hydrodistillation were analysed by Gas chromatography-mass spectrometry and its antimicrobial activity evaluated. Thirty-eight constituents were identified, representing an average of 73.64-99.95% of the total oil composition. The main constituents of the inflorescence were heptacosane (30.23%), phytol (17.41%) and the leaf oil mainly consisted of 11-Octadecenoic acid, methyl ester (41.00%), squalene (16.40%) and hexadecanoic acid, methyl ester (10.19%) while the stem consisted majorly of 4-(1,3,3-trimethyl-bicyclo[4.1.0] hept-2-yl)-but-3-en-2-one (28.10%), 3',8,8'-trimethoxy-3-piperidyl-2,2'-binaphthalene-1,1',4,4'-tetrone (22.06%). The rhizome oil contained mainly octadecane, 3-ethyl-5-(2-ethylbutyl) – (18.23%). The antimicrobial results showed that the oils exhibited varying degrees of activity against tested microorganisms at 12.5-100 μg/mL, except for the stem oil, which showed no antifungal activity. The antimicrobial activity of the essential oils showed in vitro in this study could justify the use of the plant in the treatment of infectious diseases in traditional medicine.

Keywords: Costus lucanusianus J. Braun & K. Schum, Essential oils, Gas chromatography-mass spectrometry, Antimicrobial activity, Costaceae.