Antimicrobial Activities of Essential Oils from Hura crepitans (L.), Monodora myristica (Gaertn Dunal) and Xylopia aethiopica (Dunal A. Rich) Seeds

Background: Despite the fact that essential oils are used as food and medicine, oils of rain forest plants remain largely uninvestigated.
Aims: To investigate the physico-chemical properties and antimicrobial activities of essential oils from Hura crepitans, Xylopia aethiopica and Monodora myristica.
Place and Duration of Study: This study was carried out in the Department of Microbiology, Ekiti State University, Ado-Ekiti, Nigeria between September, 2009 and January, 2010.
Methodology: Standard methods were used to determine the physicochemical properties of the oils while antibacterial and antifungal properties were determined by agar well dilution and poisoned food assay respectively.
Results: Hura crepitans had the highest acid value (9.8 mg KOH/g) and free fatty acids (12.15% oleic acid). Xylopia aethiopica had the highest activity against the test organisms while H. crepitans was the least effective on the fungal isolates. The oils were most effective against Salmonella typhi followed by Enterobacter sp. Pseudomonas aeruginosa showed the highest resistance to the essential oils. At 100mg/ml, the oils inhibited all the test bacteria with the diameter of zone of inhibition ranging from 6.0mm-17mm while the mean radial fungal growth was lower. The results indicate that essential oils are promising alternatives to standard antimicrobials.
Conclusion: Xylopia aethiopica had relatively better antibacterial and antifungal activities; hence could be formulated in creams and ointments for the treatment of superficial infections and capsules for the treatment of gastrointestinal tract infections. However its toxicity requires further investigation.