Obtenção do óleo essencial do cará-moela (Dioscorea bulbifera) e análise via espectroscopia em infravermelho com transformada de Fourier - FTIR

Abstract

Essential oils are specialized metabolites found in plants, and form a complex mixture of organic compounds. Studies indicate a great inhibitory potential for the growth of microorganisms, thus being part of the plant's defense mechanism, protecting them from diseases and pests. To obtain the essential oil from the leaves of Dioscorea bulbifera (air yam), extraction was performed using n-hexane as a solvent in the Soxhlet extraction apparatus, from leaves dried in an oven and crushed in a knife mill. This extraction was carried out using a series extraction system, in order to perform the triplicate simultaneously, reducing cooling water waste. To ensure that the cooling water would be at a similar temperature in all the apparatus, aluminum coils dipped in water and ice were used, so that heat exchange occurred between the water that passed through the system. This process lasted for a period of 6 hours, where the system kept refluxing the solven tin a constant manner, at temperatures between 67°C and 72°C. The triplicate extracts were then rotoevaporated and taken for analysis in an FTIR spectrometer. Analyzing the results, signs were observed in the region of 3400 cm-1, indicating a hydroxyl functional group (-OH) and consequently alcohols and phenols; in the ranges between 3300 cm-1 and 2500 cm-1, indicating alkanes and carboxylic acids; between 1600 cm-1 and 1460 cm-1, indicating aromatic rings; between 1720 cm-1 and 1750 cm-1, indicating esters and aldehydes; 1345 cm-1 and 1480 cm-1, indicating nitrogen compounds and alkanes; slight signs between 1400 m-1 and 1000 cm-1, indicating the presence of amines and esters, and finally between 1000 cm-1 and 660 cm-1, indicating once again the presence of amines and esters, but also of alkenes.