Composition and anti-bacterial activity analysis of citronella oil obtained by hydrodistillation: Process optimization study

Hydro-distillation was performed to determine the quantity of essential oil in different parts of Java Citronella (Cymbopogon winterianus Jowitt) plant. Parameters affecting the oil extraction process were evaluated using Response Surface Methodology. The generated second order polynomial model was highly significant with R2 = 0.9744 and P < 0.0001. Highest yield of 2.38% vw−1 was obtained using the leaves part at distillation time of 180 min, which was about 40% more than stems part and 17% more than whole aerial parts. Higher essential oil content of fresh plant (2.43% on a dry weight basis) compared to dried plant (2.12% on a dry weight basis) indicates that the moisture content has a significant effect on oil yield. GC/MS analysis of the oil extracted from leaves part revealed about 95% of commercially important compounds viz. citronellal (55.23%), geraniol (26.29%) and citronellol (13.41%), indicated very high quality citronella oil. The oil was found effective against all the six tested bacteria strains namely Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia and Escherichia coli, which revealed that citronella oil could be applied for the treatment of infections caused by various gram positive or negative pathogenic organism. The hydrosol obtained after hydro-distillation was analyzed using HPLC and was found to contain sugar alcohols such as adonitol, erythritol and mannitol which could be utilized in nutraceutical industries.