Gas chromatography-mass spectrophotometry volatilomics for antibacterial activity of essential oils from temu kunci grown at various altitudes

Volatile compounds of temu kunci (Kaempheria pandurata) essential oil were reported to inhibit various bacteria. However, their composition from plants grown at various altitudes varied, hence their antibacterial activity might vary. This study examined the volatile compounds of temu kunci essential oil using metabolomic approaches, their antibacterial activity toward Bacillus cereus , Staphylococcus aureus and Salmonella Typhimurium, as well as the mechanism of inhibition. The study consisted of volatile compounds profiling through gas chromatography-mass spectrophotometry, multivariate data analysis, inhibition study using disk method and assessment of the inhibition mechanism. The study showed that the volatile compounds were affected by the altitude of plant growth and able to inhibit the tested patho-gens significantly. The principal component analysis model had Q(2) value of 0.568 as a goodness of prediction and R2X value of 0.829 as the X variable described by model, suggesting that the model's prediction was good. Using the partial least square model, the volatile chemical compounds assumed to affect the antibacterial activity toward B. cereus was beta-bisabolene, Staph. aureus was myrtenol and S. Typhimurium was cis-beta-ocimene. Bacterial exposure to temu kunci essential oil causes cell membrane damage, as significant increase in cell leakage occured along with the increased essential oil's concentration.