Composición química y actividad AChE-BuChE del aceite esencial de palo santo Bursera graveolens (Kunth) Triana & Planch de Jipijapa, Ecuador / Chemical composition and AChE-BuChE activities of the essential oil of palo santo Bursera graveolens (Kunth) Tr iana & Planch from Jipijapa, Ecuador

Abstract: This article describes the chemical composition, physical properties and acetylcholinesterase (A ChE) and butyrylcholinesterase (BuChE) activity of stem - distilled essential oil (E O ) from Bursera graveolens wood chips, Burseraceae. The plant material was acquired in Quimis (Bosque de Sancán), city of Jipijapa in the province of Manabí, coastal region o f Ecuador. Thirty - six components were identified by CG - MS, which represented 98.54% of the volatile oil. The main components were limonene (68.52%) and mentofuran (20.37%). The hydrocarbon monoterpenes constituted the most abundant fractions. The average y ield of the E O was 1.26%. Regarding the physical properties of E O , the following values were obtained: relative density (1,029 g/mL), refractive index (1,477) and specific rotation (+4,567). The E O presented IC 50 inhibition values of 47.2 and 51.9 µg/mL fo r the enzymes AChE and BuChE, respectively.

Resumen: Este artículo describe la composición química, propiedades físicas y actividad acetilcolinesterasa (AChE) y butirilcolinesterasa (BuChE) del aceite esencial (AE) destilado a vapor de astillas de madera de Bursera graveolens , Burseraceae. La materia vegetal fue adquirida en Quimis (Bosque de Sancán), ciudad de Jipijapa en la provincia de Manabí, región costera d e Ecuador. Treinta y seis componentes fueron identificados por CG - MS, que representaron al 98.54 % del aceite volátil. Los componentes principales fueron limoneno (68.52%) y mentofurano (20.37%). Los monoterpenos hidrocarburos constituyeron las fracciones m ás abundantes. El rendimiento medio del AE fue de 1.26%. Con respecto a las propiedades físicas del AE se obtuvo los siguientes valores, densidad relativa (1.029 g/mL), índice de refracción (1.477) y rotación específica (+4.567). El AE presentó valores de inhibición IC 50 de 47.2 y 51.9 µg/mL para las enzimas AChE y BuChE, respectivamente.

The powerful high pressure tool for protein conformational studies

The pressure behavior of proteins may be summarized as a the pressure-induced disordering of their structures. This thermodynamic parameter has effects on proteins that are similar but not identical to those induced by temperature, the other thermodynamic parameter. Of particular importance are the intermolecular interactions that follow partial protein unfolding and that give rise to the formation of fibrils. Because some proteins do not form fibrils under pressure, these observations can be related to the shape of the stability diagram. Weak interactions which are differently affected by hydrostatic pressure or temperature play a determinant role in protein stability. Pressure acts on the 2°, 3° and 4° structures of proteins which are maintained by electrostatic and hydrophobic interactions and by hydrogen bonds. We present some typical examples of how pressure affects the tertiary structure of proteins (the case of prion proteins), induces unfolding (ataxin), is a convenient tool to study enzyme dissociation (enolase), and provides arguments to understand the role of the partial volume of an enzyme (butyrylcholinesterase). This approach may have important implications for the understanding of the basic mechanism of protein diseases and for the development of preventive and therapeutic measures.