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Variation in the chemical composition of essential oils from <i>Artemisia afra</i> (Jacq) ex-Wild leaf obtained by different methods and the effect of oil extracts on <i>Artemia salina L</i>


Oluwagbenga O. Adeogun
Alfred Maroyi
Anthony Jide Afolayan

Abstract

Purpose: To determine the essential oils extracted from fresh and dried leaves of Artemisia afra using hydrodistillation (HD) and solvent free microwave extraction (SFME) methods and investigate the effects of the oils on Artemia salina.
Methods: The essential oils were obtained from fresh and dried leaves of Artemisia afra using hydrodistillation and solvent-free microwave extraction methods. The compounds present in the oils were analysed by gas chromatography-mass spectrometry (GC-MS). The oils were assayed for hatchability and lethality  activities on Artemia salina for 72 h. The lethal concentration (LC50) required to kill 50 % of the population of brine shrimp by each test oil was determined using a Probit regression analysis.
Results: The most abundant compound was thujone (32.02 and 30.02 % in fresh leaf by HD and SFME methods, respectively) and in dried leaf (26.57 and 25.82 %, by HD and SFME methods, respectively). Mean hatchability success rate of all the oils was 70 % while lethality activity was 30 % after 72 h at the lowest  concentration of the test oils. Half-maximal lethal concentration (LC50) on Artemia salina was 206.97 and 406.48 μg/mL of the oil from fresh leaf obtained by HD and SFME, respectively, while for the dried leaf, it was 277.18 and 669.30 μg/mL for the oil produced by HD and SFME, respectively.
Conclusion: The phytoconstituents in each oil varied based on the method of  extraction and the state of the leaf before and after extraction. Furthermore, the toxic activity of the oils against Artemia salina suggests that they may possess anticancer properties but this needs to be further investigated.


Keywords: Artemia salina, Artemisia afra, Essential oils, hydrodistillation, Solvent-free microwave extraction, Hatchability, Lethality


Journal Identifiers


eISSN: 1596-9827
print ISSN: 1596-5996