Extratos de sementes de gergelim preto (Sesamum indicum L) obtidos via CO2 supercrítico: isotermas de rendimento global, dados cinéticos e ajustes, ácidos graxos totais, fitosteróis e efeitos neuroprotetores

Abstract

In Brazilian folk medicine, black sesame (Sesamum indicum L) seeds is one of the most important ingredients present in the tea used to treat encephalic stroke victims. Nevertheless, isolation of black sesame extracts to medicinal finality using supercritical fluid technology has not been performed. The objective of this work was to investigate some process variables of supercritical fluid extraction in black sesame to generate extracts applicable in stroke research. Two isothermal (40 and 60 °C) were explored, combined with pressures that ranged from 200-400 bar, at a constant CO2 mass flow rate of 5,9 x 10-5 kg/s. The global yields ranged from 37-53% in dry basis. The highest mass yield was obtained at 60 °C and 400 bar. The fatty acid composition comprised a high unsaturated/saturated ratio. Chromatographic analysis of phytosterol content in the high global yield extract revealed higher amounts of β-sitosterol + sitostanol, cholesterol, campesterol + campestanol + 24-methylene cholesterol, Δ-5 avenasterol and stigmasterol, while lower levels of Δ-5,24 stigmastadienol, brassicasterol, clerosterol + Δ-5-23 stigmastadienol, Δ-7 avenasterol, eritrodiol and Δ-7 stigmastenol were present in the black sesame extract. Overall extraction curves from the supercritical fluid extraction in lower and higher global yields (200 e 400 bar at 60 °C) fitted the Tan and Liou (1989), Martinez et al. (2003), Esquível et al. (1999), Goto et al. (1993) e Sovová models (1994 and 2012). The models of Tan and Liou (1989), Goto et al. (1993) and Sovová (1994 and 2012) presented the best residual sum of squares values. Pilot experiments suggest that black sesame extract is neuroprotective following endothelin-1 induced focal ischemia into the motor cortex of male adult rat, observing indications that a prejudicial cell form for the stroke`s status was inhibited by the treatment.