Aktivitas Antibakteri dan Toksisitas Minyak Serai Dapur (Cymbopogon citratus) dengan Perlakuan Pemekatan pada Suhu Berbeda

Abstract

Lemongrass (Cymbopogon citratus) is a species of the genus Cymbopogon that produces essential oils with a distinctive fragrance. Lemongrass oil can be an alternative choice of natural antibacterial agents during the Covid-19 pandemic in hand soap and hand sanitizer because it is easy to obtain and the price is affordable. Lemongrass essential oil is reported to contain many chemical compounds that contribute to its activity. Chemical compounds reported in lemongrass essential oil include β-mirsen, 3-undekuna, neral, geranial, nerol, geranil asetat and juniper camphor. Differences in the composition of chemical compounds in essential oils can affect the bioactivity of this essential oils. The differences in the composition of chemical compounds in lemongrass essential oil are influenced by several factors, including the treatment in the distillation process and after the distillation process. Evaluation of the effect of post-distillation temperature on the chemical components in lemongrass oil is an aspect that we need to work on as an effort to ensure its quality and efficacy. In this study, the procedure was started by distillation of lemongrass at a temperature of 100–105ºC for 3,5 hours and then stored in the refrigerator. As a comparison, commercial lemongrass oil was provided and then concentrated using a rotary evaporator at different temperatures, at 30, 40, and 50 ºC. There are five samples of lemongrass oil which are then ready to be analyzed. The toxicity test was carried out using the brine shrimp lethality test (BSLT). The results of the BSLT test showed that the five samples had an LC50 value of <1000 ppm. In addition to BSLT, antibacterial activity tests were carried out on lemongrass oil which included minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Antibacterial test was conducted against S. aureus and S. epidermidis by disc method. The result showed that lemongrass oil has very strong antibacterial properties against S. aureus and is in the strong category against S. epidermidis. Meanwhile, the MIC values of lemongrass oil without evaporation treatment was 1250 ppm and 625 ppm, respectively against S. aureus and S. epidermidis. The MBC values of the sample was 2500 ppm and 10000 ppm against S. aureus and S. epidermidis, respectively. While the MIC values of lemongrass oil concentrated at 40 ºC were 5000 ppm and 2500 ppm against S. aureus and S. epidermidis, respectively. The analysis of chemical composition using GC-MS shows that in lemongrass oil without evaporation treatment there are 13 compounds detected with the abundance of each compound > 1% while in lemongrass oil evaporated at 40 ºC for 11 compounds was detected. The main constituent in lemongrass oil was citral, neral and β-mirsen.