The Chemical Composition and Antidiabetic, Neuroprotective and Cytotoxic Activities of Soft Hulls (Mesocarp) of Pistachio (Pistacia vera) Fruits

Abstract

Pistachio (Pistacia vera L.) is an important cultivated plant in the Southeastern Anatolia region and its fruits are widely used in the food industry. The previous studies mostly focused on the food minerals and components. However, there is no study on chemical components and biological activity of the soft hulls of the pistachio fruits. In this study, it was focused on the acetone and water extracts of the soft hulls of pistachio fruits. Hence, the acetone extract was subjected to sephadex LH-20 column chromatography and fractioned into five fractions (Frs. A-E) according to molecular weight of components. A triterpen compound isolated from the Fr. B by crystallation method and its chemical structure was characterized as masticadienonic acid by spectroscopic methods. The fractions contain a mixture of the anacardic acids 13:1, 15:2, 15:1 and 17:1 and their derivatives according to their spectroscopic data and GC-MS analysis. Shikimic acid used in the synthesis of the oseltamivir, antiviral agent was also purified at high yield (14.36%) from the water extract of the soft hulls of pistachio fruits. In order to explore the antidiabetic properties of the pure compounds, the extracts and the fractions, their inhibition effects were determined on the activities of digestive enzymes (α-glucosidase and α-amylase). All of the extracts, masticadienonic acid and the fractions containing the anacardic acids strongly inhibited the α-glucosidase activity much more than acarbose. However, all applications exhibited much weaker inhibitory properties againts α-amylase, as compaired to the inhibition effect of the acarbose. Furthermore, the treatments of mesocarps of Pistachio fruits acted as much weaker inhibitors against AChE, whereas the acetone extract and its fractions containing different rates of anacardic acids were powerful agents against BChE as strong as neostigmine and galantamine. The cytotoxic activities of the extracts and the compounds against HUVEC, A549 and H1299 cells were also determined using the MTT analysis method and it was determined that the acetone extract and the compounds, masticadienonic and shikimic acids showed cytotoxic effects on the cells