Chemical composition and antibacterial properties of curcuma longa volatile oil and solvents extracts against selected clinical bacteria

Turmeric ( Curcuma Longa ) rhizome is a natural product of plant that is usually consumed. Its bioactive compounds can be explored to control bacterial growth. This study evaluated the chemical composition of turmeric volatile oil and extracts against clinical bacteria. Bioactive compounds of turmeric rhizome were subjected to hydrodistillation using Clevenger apparatus. The non volatile extracts were carried out using Hexane and Methanol. The oil and the extracts were subjected to gas chromatography-mass spectrometry (GC-MS) and were evaluated for their antibacterial activity by agar well diffusion assay. Minimum inhibitory concentration (MIC) was determined using the standard method. The results showed that eighty-four (84) compounds were identified in turmeric volatile oil with ar-turmerone (19.01%), cedr-8-ene (10.13%), and β-terpinene (10.01%) being predominant. The main constituents of turmeric n-hexane were turmerone (13.39%) and14-beta-H-pregna (9.05%). Methanol extracts contained turmerone (12.46%) and 14-beta-H-pregna (8.72%) respectively. Findings revealed that volatile oil and the extracts have antibacterial properties against S. aureus, K. ornithinolytica , and C. gillenii , turmeric n-hexane extract had the highest zone of inhibition (28 ± 1.03 mm) against C. gillenii followed by K. ornithinolytica (26 ± 1.63 mm), and S. aureus (25 ± 0.33 mm). The MIC results showed that turmeric volatile oil showed considerable activity against K. ornithinolytica at concentration of 6.25 mg/ml than for all other bacteria. In conclusion, the volatile oils of turmeric oil and extracts have potentials for use as a natural agent against some clinical bacterial species.