Avaliação da composição química, atividade antioxidante e antimicrobiana do óleo de cipó-de-alho (Mansoa standleyi) (Steyerm.) A. H. Gentry (Bignoniaceae) obtido via extração supercítica

Abstract

Mansoa standleyi is popularly known as "cipó-de-alho" because of its characteristic garlic odor (Allium sativum). The plant has an inhibitory effect on bacteria and fungi growth. The objective of this work was to evaluate the chemical composition, antioxidant and antimicrobial activity of the oil obtained from M. standleyi leaves via supercritical fluid extraction (SFE) and conventional extraction (Hydrodistillation). The SFE tests were performed using supercritical CO2, static extraction time of 30 min and dynamic time of 180 min, CO2 flow of 2.5 L/min and raw material mass of 10 g. The temperature and pressure variables were selected in order to obtain a difference in the CO2 density (𝜌𝐶𝑂2) in the 35 and 45 ºC isotherms combined with the pressure values of 100, 200, 300, and 400 bar. The results obtained allow us to verify that the global yield values of SFE on dry basis show significant differences between them (p≤0.05), with values varying from 0.87 to 2.02%. The highest average found refers to 400 bar/35 ºC condition (𝜌𝐶𝑂2 = 972.26 kg/m3). However, in Hydrodistillation extraction the oil yield was 0.14%. The results of phytochemical screening by high performance thin layer chromatography (HPTLC) evidenced the presence of terpenes, fatty acids, phenolic compounds, and flavonoids. It was demonstrated the presence of substances with antioxidant activity for all oils obtained with SFE, being observed a better identification in the oils obtained at high pressures. In the quantitative analysis of chemical composition, it was observed that the values ranged from 31.87 to 72.06 mg EAG/g oil in the content of total phenolic compounds. In relation to the antioxidant activity, the values ranged from 457.64 to 2475.55 EC50 expressed in g of oil/g of DPPH, the best results being obtained in the condition of 400 bar/35 ºC. In the fatty acid profiles of M. standleyi oil obtained by SFE, the results indicated that there was a difference in the fatty acids qualitative composition detected, in function of the operational extraction condition, where the presence of linoleic (≅95%), palmitic (≅12%), and oleic (≅5%) acid was observed. The chemical constituents identified in the obtained oil by Hydrodistillation were identified as sulfur compounds, phenols, and alcohols. The antimicrobial activity in vitro analysis showed that the oil obtained by SFE presents an antibacterial action against Stapphylococcus aureus and Escherichia coli. Finally, M. standleyi oil represents an alternative for future use in the treatment of diseases caused by microorganisms.