Abstract

JARAMILLO C, Beatriz Eugenia; DUARTE R, Edisson  and  DELGADO, Wilman. Bioactivity of essential oil from Ocimum micranthum Willd collected from Bolivar department, Colombia. Rev Cubana Plant Med [online]. 2014, vol.19, n.2, pp. 185-196. ISSN 1028-4796.

Introduction: Ocimum micranthum Willd is a herbaceous plant of the family Lamiaceae native to tropical and subtropical regions of America and grown for medicinal and/or ornamental purposes. Infusion of this plant is used for gastrointestinal conditions such as ulcers, gastritis, intestinal fever, inflammation, dysentery, vomiting, stomach pain and as vermifuge. Objectives: determine the volatile chemical composition of essential oil from Ocimum micranthum Willd and evaluate its in vitro antifungal, repellent, insecticidal and antioxidant activities. Methods: essential oil (EO) from O. micranthum fresh leaves was obtained by hydrodistillation. Volatile chemical composition was determined by gas chromatography coupled to a mass spectrometric detector (GC-MS). The fumigant activity assay (insecticidal) was performed against Sitophilus zeamais . Antifungal activity was determined against pathogenic fungus Fusarium oxysporum f. sp. Dianthi, and repellent activity against Tribolium castaneum Herbst. Antioxidant capacity was analyzed with the DPPH radical decolorization assay. Results: the most abundant compound found in O. micranthum EO was eugenol (60.37 %), followed by eucalyptol (12.09 %), cis-terpineol (4.25 %), a-terpineol (4.43 %), and δ-cadinene (1.27 %). O. micranthum EO was active against F. oxysporum, with a mycelial inhibition of 98.8 % at 176.5 uL EO / L air, read at 72 hours, and a mortality rate of 66.7 % against S. zeamais at 500 uL EO / L air, after 24 hours of exposure. Repellent activity was 92.5 % and 93.3 % at 2 and 4 hours of exposure, respectively. DPPH radical inhibition was 93.92 %. Conclusions: Essential oil from O. micranthum showed significant antifungal, repellent and fumigant activities. Thus it could become an alternative to replace synthetic fungicides and insecticides.

Keywords : Ocimum micranthum; essential oil; antifungal; insecticide; antioxidant; gas chromatography.

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