Abstract:
There are several bioactive plants in Ethiopia that can produce essential oils. However, their antimicrobial and insecticidal activities of these plants are not widely assessed. Therefore, the aim of this study was to assess some biological activity from essential oil of Fagaropsis angolensis seed, Callistemon citrinus and Melaleuca armillaris leaves from Jimma and surroundings, Ethiopia. The hydro-distillation extraction method was used to extract essential oils, and the constituents of essential oil were identified by using Gas chromatography mass spectrometry analysis. The antimicrobial activities against bacteria (Bacillus cereus, Staphylococcus aureus, Salmonella typhimurium and Escherichia coli), fungi (Candida albicans) using broth micro-dilution bioassay and insecticidal activities against insect (termites) using no-choice bioassay were assessed. The yield of essential oils was 2.58%, 1.00% and 2.29% for Fagaropsis angolensis seed, Callistemon citrinus leaves and Melaleuca armillaris leaves respectively. Acid values were 2, 4 and 4 for Fagaropsis angolensis seed, Callistemon citrinus and Melaleuca armillaris leaves essential oil were observed respectively. Saponification value 80.50, 72.45 and 72.45 of the essential oil were observed for Fagaropsis angolensis seed, Callistemon citrinus and Melaleuca armillaris leaves essential oil respectively. The major components identified from Fagaropsis angolensis seed were Bicyclo (3.1.0) hexane, 4-methylene-1-(1-methylethyl) - (sabinene) (72.29%) and Terpinen-4-ol (8.06%). From Callistemon citrinus leaves were Acetic acid, chloro-ethyl ester (13.61%), and Eucalyptol (1, 8-cineol) (72.46%). From Melaleuca armillaris leaves were Eucalyptol (80.08%) and α-terpineol (8.66%). The antimicrobial activities of essential oils of Fagaropsis angolensis seed were with MIC 0.40 ± 0.29 against (B cereus, S aureus and S typhimurium), 0.14 ± 0.09 against (E. coli) and 1 ± 0 against (C albicans), Callistemon citrinus leaves MIC 3.64 ± 2.57 against (E. coli), 1.21 ± 0.86 against (B cereus, S aureus and S typhimurium), and 1 ± 0 against (C albicans) and Melaleuca armillaris leaves MIC 3.64 ± 2.57 against (E. coli), 3.64 ± 2.57 against (B cereus and S aureus), 10.93 ± 7.72 against (S typhimurium), and 1 ± 0 against (C albicans). Moreover, all the tested oils were bacteriostatic and fungistatic against all tested strains. The 100 % mortality of termites was observed for 5% essential oils with short time of exposure from10min to 3 hours.
