Comparative evaluation of essential oils from lippia javanica L leaf obtained by two methods and their effect on artemia salina L

Abstract

Purpose: To compare the chemical constituents of essential oils extracted from fresh and dried leaves of Lippia javanica by hydrodistillation (HD) and solvent-free microwave extraction methods (SFME), and evaluate their effects on Artemia salina. Methods: Oil was extracted from the fresh and dried leaves of Lippia javanica by HD and SFME methods, and assayed for chemical constituents using gas chromatography-mass spectroscopy (GC-MS). The oils were tested for hatchability and preliminary toxicity on Artemia salina for 72 h. The lethal concentration required to kill fifty percent of A. salina (LC50) was determined by Probit regression analysis. Results: Mesityl oxide was the most abundant compound in the essential oils. Mesityl oxide content of fresh and dried leaves extracted with HD was 25.33 and 29.83 %, respectively, while SFME method yielded 19.75 and 13.46 %, respectively. The average hatching success rate of the oil was 30 % success while lethality was 100 % after 72 h. Median lethal concentration (LC50) of fresh and dried leaves extracted by HD was 90.11 and 128.49 µg/mL, respectively, whereas SFME method resulted in LC50 of 96.52 and 101.13 µg/mL, respectively. Conclusion: The results show that the essential oil yield is not significantly affected by the extraction methods used. However, the hatchability and lethality of the oils varied with the extraction method used.