Copuazu proyecto bioquimica

Phytochemical and antioxidant characterization of the fruit of black sapote (Diospyros digyna Jacq.)
Abstract
Consumption of fruits and vegetables has been associated with a healthy state which has been attributed, in part, to their antioxidant capacity. Characterization of the bioactive compounds with antioxidant activity found in fruits cultivated in the tropic is limited. Thus, the objectiveof the present work was the characterization of phytochemicals and antioxidants of the fruit of black sapote (Diospyros digyna Jacq.). HPLC-DAD-Mass Spectrometry (HPLC-MS) analyses were used to identify and quantify phenolics, carotenoids and tocopherols. Total soluble phenolic content was 247.8 mg GAE/100 g fw (fresh weight). Important phenolics identified were sinapic acid, myricetin, ferulicacid, and catechin. Total carotenoid content was 399.4 μg of β-carotene/100 g fw, and β-carotene and lutein were the main carotenoids identified. δ-Tocopherol concentration was 672.0 μg/100 g dry weight. Antioxidant capacity as measured by the DPPH and FRAP assays was higher in the hydrophilic than in the lipophilic extract, and it is thought to be due mainly to the phenolic content of this fruit.Results suggest that the fruit of black sapote has an antioxidant capacity comparable to other important fruits, and its inclusion in the diet is therefore recommended.

1. Introduction
There has been an increase in the development of chronic diseases such as cancer, diabetes, cardiovascular disease, and hypertension in the last few years, which can be explained, at least in part, by factorssuch as diet and lifestyle (Yahia, 2010). Epidemiological evidence suggests an inverse relationship between a high intake of fruits and vegetables and incidence of these diseases ([Lampila et al., 2010], [Southon, 2000], [WCRF-AICR, 2007]and [Yahia, 2010]). Because of that, the interest for identifying and characterizing phytochemicals in fruits and vegetables that may be related to these effects isof great interest (Barros, Carvalho, & Ferreira, in press). Phytochemicals are a group of compounds present in fruits and vegetables that exert a potential protective role against development of diseases associated with aging like cardiovascular disease, inflammation, and cancer ([Temple, 2000],[Willett, 1994] and [Willett, 1995]). Oxidative stress has been implicated in the development ofthese disorders ([Diaz et al., 1997], [Harman, 1995] and[Smith et al., 1996]). Oxidative stress is induced by harmful free radicals damaging lipids, DNA, and proteins (Halliwell & Gutteridge, 1989). Among phytochemicals, phenolics are secondary plant metabolites which have been shown to be responsible, at least in part, for the observed protective effects of fruit and vegetable consumption(Hertog, 1996). Their antioxidant activity is mediated by inactivation of damaging free radicals (Haslam, 1998). Another group of phytochemicals, carotenoids, have also been shown to have antioxidant activity, besides the well known provitamin A activity of some of them (Yahia & Ornelas-Paz, 2010). Among carotenoids, lycopene has been the object of extensive research which suggests its antioxidantrole and antiproliferative activity in cancer cells ([Heber, 2004] and [Obermuller-Jevic et al., 2003]). In addition, vitamins C and E have largely been known for their role as antioxidants in the body ([Burton and Ingold, 1981] and [Huang et al., 2005]). Therefore, characterization of phytochemicals in fruits and vegetables is of great importance. Tropical fruits, especially minor fruits such asblack sapote, have been little characterized for their phytochemical content. Corral-Aguayo, Yahia, Carrillo-Lopez, and Gonzalez-Aguilar (2008) reported that vitamin E in black sapote fruit was the highest among 8 fruits, and considered black sapote and avocado as relatively good sources for this vitamin. Black sapote (Diospyros digyna Jacq.) belongs to the Ebenaceae family and is native to the...