AVALIAÇÃO DE TEOR E COMPOSIÇÃO QUÍMICA DOS ÓLEOS ESSENCIAIS DE TRÊS ESPÉCIES DE HYPTIS, SUBMETIDAS A DIFERENTES VELOCIDADES E TEMPERATURAS DE SECAGEM

Abstract

The Hyptis genre is widely spread in the Brazilian cerrado; many species have medicinal properties and pharmaceutical relevance. The diversity of the biological activity of Hyptis has led to studies of the chemical composition of the essential oils present in the plant. It is known that these species s have antimicrobial, anticancer propertie, are also used in flavoring compositions for foodstuffs and fine fragrances. Essential oils are secondary metabolites resulting from the balance between their formation and their transformation that occur during plant growth, due to three factors: genetic, environmental and cultivation techniques. This work aimed to investigate the influence of different temperatures and air velocities of drying, which can promote changes in the content and composition of essential oils of Hyptis marrubioides Epling, Hyptis suaveolens (Linnaeus) Poiteau and Hyptis pectinata (Linnaeus) Poiteau. The methodology began with the production of seedlings of the three species in the greenhouse in mid-August 2013, with seed germination in trays containing Trimix substrate, kept under irrigation and later transplanted to the field. Drying was performed in December 2015 for the species H. suaveolens and H. pectinata and in March 2015 for H. marrubioides in the Post-Harvest Vegetable Products Laboratory, preceded by the determination of each species moisture content in circulation oven at 103 °C by 24 xix hours. The leaves were dried in a fixed bed dryer adjusted to an automation system controlling the temperature at 35, 45 and 55 °C and the drying air at controlled speed of 1 m s -1 and 2 s -1 . The extraction of oil occurred by hydrodistillation using a Clevenger apparatus. A total of 60 g of dried leaves for each repetition by 50 minutes were used. The oil was extracted with dichloromethane and then promoted if its concentration with the total solvent evaporation in the gas exhaust hood at room temperature. After extraction, the oils were sent to the Federal University of Viçosa - Minas Gerais, where they underwent analysis by gas chromatography coupled to a mass spectrometer for chemical characterization. The chemical identification showed that the major compounds for the three species were cis- and trans-thujone with their higher concentrations 15.77 ± 5.84; 22.55 ± 8.24%, respectively, at 35 °C for Hyptis marrubioides species. For Hyptis suaveolens species the caryophyllene oxide had high concentration at a temperature of 45 °C and values of 48.91 ± 7.64 and 45.60 ± 19.85% to speed of 1 s-1 and 2 m s1 respectively. As for the Hyptis pectinata species, the chemical analysis also showed the compound caryophyllene oxide as major compound in all drying conditions, being checked their highest concentrations, 52.91 ± 2.23 and 55.43 ± 7.78% to 55 °C to speed of 1 m s-1 and 2 m s-1 respectively..