Brine shrimps toxicity, bactericidal and antifungal activity of monodora myristica (Gaertn) essential oils

Abstract

Essential oils from the seeds and stem bark of Monodora myristica were obtained through hydro-distillation using Clevenger-type apparatus. The toxicities of the volatile oils were assayed using the brine shrimps’ toxicity assay and the LC50 (median lethal concentration) was calculated using Finney’s probit analysis. The antimicrobial assay was carried out using the agar diffusion method. Ten microbes consisting of five bacteria and five fungi were used in this study. The bacteria were three species of Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Salmonella typhi) and two Gram-negative bacteria (Escherichia coli, and Pseudomonas aeruginosa) and the fungi were Candida albicans, Candida krusei, Candida glabrates, Aspergillus niger and Penicillum nostatum. Monodora myristica seeds and stem-bark displayed an equal level of toxicity (LC50 = 0.1 μg/mL) in brine shrimps lethality assay. In comparison to standard antibiotics (Gentamicin) and antifungal agent (Tioconazole), the activity of Monodora myristica essential oils for growth inhibition of the test microorganisms was low with the zone of inhibition of 18.0 ± 2.0 mm recorded against Bacillus subtilis, the most susceptible organism to the essential oil.