Chemical composition, antiacetylcholinesterase inhibition and toxicity activities of essential oil from Hyptis dilatata (Lamiaceae) flowers

The content and chemical composition of the essential oil may vary in certain species according to the climatic period. The aim of this study was to evaluate the influence of seasonality on the chemical composition of the essential oil from Hyptis dilatata flowers, to perform biological activities such as antimicrobial, inhibition of acetylcholinesterase enzyme and to evaluate the toxicity of the essential oil using for the test as indicator Artemia salina. H. dilatata flowers were collected in rainy and dry periods and extracted by hydro distillation using extractor of Clevenger condenser double Spell model. Analysis of essential oil resulted in 22 chemical components. The major constituents for dry and rainy periods were α-pinene (26.2 and 10.9%), 3-Carene (12.2 and 3.7%), fenchone (17% and 14.8%) and β-cariophyllene (16.36 and 30.9%), respectively. The essential oil inhibited the acetylcholinesterase enzyme in 93.4% (rainy period) and 92.4% (dry period). Between the dry and rainy periods, the best LC50 in microbial activity in vitro was obtained in the rainy period tested in Staphylococcus aureus bacterium (LC50 49.8 mg ml-1). The cytotoxic activity of A. salina in H. dilatata essential oil proved LC50 results below of 100 μg ml-1. Therefore, the chemical characterization and testing of biological activities of essential oils showed promising results in the search for new active substances and development of bioproducts of vegetable origin. Key words: Hyptis dilatata, α-pinene, fenchone, β-cariofilene, 3-carene.