Lee, J., Y.S. Kim, J. Lee, S.C. Heo, K.L. Lee, S.W. Choi, Y. Kim, 2016. Walnut phenolic extract and its bioactive compounds suppress colon cancer cell growth by regulating colon cancer stemness.Nutrients. 8, 439; doi:10.3390/nu8070439.
Abstract: Walnut has been known for its health benefits, including anti-cardiovascular disease and anti-oxidative properties. However, there is limited evidence elucidating its effects on cancer stem cells (CSCs) which represent a small subset of cancer cells that provide resistance against chemotherapy. This study aimed to evaluate the anti-CSCs potential of walnut phenolic extract (WPE) and its bioactive compounds, including (+)-catechin, chlorogenic acid, ellagic acid, and gallic acid. In the present study, CD133+CD44+ cells were isolated from HCT116 cells using fluorescence-activated cell sorting (FACS) and then treated with WPE. As a result, survival of the CD133+CD44+ HCT116 cells was inhibited and cell differentiation was induced by WPE. In addition, WPE down-regulated the CSC markers, CD133, CD44, DLK1, and Notch1, as well as the β-catenin/p-GSK3β signaling pathway. WPE suppressed the self-renewal capacity of CSCs. Furthermore, the WPE exhibited stronger anti-CSC effects than its individual bioactive compounds. Finally, the WPE inhibited specific CSC markers in primary colon cancer cells isolated from primary colon tumor. These results suggest that WPE can suppress colon cancer by regulating the characteristics of colon CSCs.
Baer, D., S. Gebauer, J. Novotny, 2016. Walnuts consumed by healthy adults provide less available energy than predicted by the Atwater Factors. J Nutr. 146:1–5.
Background: Previous studies have shown that the metabolizable energy (ME) content (energy available to the body) of certain nuts is less than predicted by the Atwater factors. However, very few nuts have been investigated to date, and no information is available regarding the ME of walnuts. Objective: A study was conducted to determine the ME of walnuts when consumed as part of a typical American diet. Methods: Healthy adults (n = 18; mean age = 53.1 y; body mass index = 28.8 kg/m2) participated in a randomized crossover study with 2 treatment periods (3 wk each). The study was a fully controlled dietary feeding intervention in which the same base diet was consumed during each treatment period; the base diet was unsupplemented during one feeding period and supplemented with 42 g/d walnuts during the other feeding period. Base diet foods were reduced in equal proportions during the walnut period to achieve isocaloric food intake during the 2 periods. After a 9 d diet acclimation period, subjects collected all urine and feces for ;1 wk (as marked by a Brilliant Blue fecal collection marker) for analysis of energy content. Administered diets, walnuts, and fecal and urine samples were subjected to bomb calorimetry, and the resulting data were used to calculate the ME of the walnuts. Results: One 28-g serving of walnuts contained 146 kcal (5.22 kcal/g), 39 kcal/serving less than the value of 185 kcal/ serving (6.61 kcal/g) currently used for food labeling. The ME of the walnuts was 21% less than that predicted by the Atwater factors (P < 0.0001). Conclusion: Consistent with other tree nuts, Atwater factors overestimate the metabolizable energy value of walnuts. These results could help explain the observations that consumers of nuts do not gain excessive weight, and improve the accuracy for food labeling.
Grace, M.H., D. Esposito, M.A. Timmers, J. Xiong. G. Yousef. S. Komarnytsky, M.A. Lila, 2016. Chemical composition, antioxidant and anti-inflammatory properties of pistachio hull extracts. Food Chemistry. 210:85-95.
Phytochemical and bioactivity analyses of pistachio hulls revealed the presence of anacardic acids (3198 mg/100 g), fatty acids (1500 mg/100 g), and phytosterols (192 mg/100 g) as major components. Carotenoids (4.93 mg/100 g), chlorophylls (10.27 mg/100 g), tocopherols (8.83 mg/100 g), and three triterpene acids (mangiferolic, isomangiferolic and mangiferonic acids) were characterized. A polar (P) extract contained quercetin-3-O-glucoside (6.27 mg/g), together with smaller concentrations of quercetin, myricetin and luteolin flavonoids, accounting for 5.53 mg/g. Gallotannins and other phenolic compounds esterified with a gallic acid moiety characterized the P extract. P extract potently inhibited the release of nitric oxide (NO) and reactive oxygen species (ROS) in lipopolysaccharide-stimulated RAW 264.7 macrophage cells. The mRNA expression levels of the anti-inflammatory cytokine COX-2 were significantly inhibited by fractions P2-P5, while IL-6 was only inhibited by fraction P3. Moreover, the P extract significantly decreased the non-mitochondrial oxidative burst associated with inflammatory response in macrophages.
Barreca, D., G. Laganà, U. Leuzzi, A. Smeriglio, D. Trombetta, E. Bellocco, 2016. Evaluation of the nutraceutical, antioxidant and cytoprotective properties of ripe pistachio (Pistacia vera L., variety Bronte) hulls. Food Chemistry. 196:493-502.
Every year tons of pistachio hulls are separated and eliminated, as waste products, from pistachio seeds. In this study the hulls of ripe pistachios were extracted with two organic solvents (ethanol and methanol) and characterized for phenolic composition, antioxidant power and cytoprotective activity. RP-HPLC-DAD-FLU separation enabled us to identify 20 derivatives, including and by far the most abundant gallic acid, 4-hydroxybenzoic acid, protocatechuic acid, naringin, eriodictyol-7-O-glucoside, isorhamnetin-7-O-glucoside, quercetin-3-O-rutinoside, isorhamnetin-3-O-glucoside and catechin. Methanol extraction gave the highest yields for all classes of compounds and presented a higher scavenging activity in all the antioxidant assays performed. The same was found for cytoprotective activity on lymphocytes, lipid peroxidation and protein degradation. These findings highlight the strong antioxidant and cytoprotective activity of the extract components, and illustrate how a waste product can be used as a source of nutraceuticals to employ in manufacturing industry.
Liu, Z, W. Wang, G. Huang, W. Zhang and L. Ni. 2016. In vitro and in vivo evaluation of the prebiotic effect of raw and roasted almonds (Prunus amygdalus). J. Sci. Food Agric. 96 (5):1836-1843.
BACKGROUND: Almonds contain considerable amounts of potential prebiotic components, and the roasting process may alter these components. The aim of this study was to compare the in vitro fermentation properties and in vivo prebiotic effect of raw and roasted almonds. RESULTS: In vitro, predigested raw and roasted almonds promoted the growth of Lactobacillus acidophilus (La-14) and Bifidobacterium breve (JCM 1192), and no significant differences were found between these two nuts. In a 4-week animal trial, daily intake of raw or roasted almonds promoted the population of Bifidobacterium spp. and Lactobacillus spp. and inhibited the growth of Enterococcus spp. in faeces and caecal contains of rats. Compared with roasted almonds, raw almonds had a greater bifidobacteria promotion effect. Besides, significantly higher β-galactosidase activity and lower β-glucuronidase and azoreductase activities in faeces or caecal contents of rats were observed with raw almonds than with roasted almonds. While, in terms of metabolic effects, the ingestion of roasted almonds resulted in significantly greater intestinal lipase activities. CONCLUSION: Both raw and roasted almonds exhibit potential prebiotic effects, including regulation of intestinal bacteria and improved metabolic activities. The roasting process may slightly reduce the prebiotic effects of almonds but significantly improve the metabolic effects.
Grundy, M.M.-L., K. Lapsley, P.R. Ellis, 2016. A review of the impact of processing on nutrient bioaccessibility and digestion of almonds. Int. J. Food Sci . Tech. 51:1937-1946.
Almond kernels contain phytochemicals and nutrients that potentially have positive health benefits in relation to heart disease, diabetes and obesity. One important mechanism associated with these benefits is an imposed limit on bioaccessibility (release) of nutrients, such as lipids, from almond tissue during mastication and digestion. Recent studies have demonstrated the importance of food structure during the digestion of plant foods. In particular, in the almond kernel, depending on its structure and degree of processing, the amount of lipid released from the almond tissue matrix and the fatty acids produced from lipolysis has been found to vary substantially. This review aims at discussing the commercial methods of almond processing and the different almond forms produced for human consumption, mainly with respect to their impact on nutrient composition, digestion and metabolism.
Grundy, M.M.L., F. Carriere, A.R. Mackie, D.A. Gray, P.J. Butterworth, P.R Ellis, 2016. The role of plant cell wall encapsulation and porosity in regulating lipolysis during the digestion of almond seeds. Food & Function 7(1):69-78.
Previous studies have provided evidence that the physical encapsulation of intracellular nutrients by cell walls of plant foods (i.e. dietary fibre) plays a predominant role in influencing macronutrient bioaccessibility (release) from plant foods during human digestion. One unexplored aspect of this is the extent to which digestive enzymes can pass through the cell-wall barrier and hydrolyse the intracellular lipid in almond seeds. The purpose of the present study was to assess the role played by cell walls in influencing the bioaccessibility and digestibility of almond lipid using a range of techniques. Digestibility experiments were performed on raw and roasted almond cells as well as isolated almond oil bodies using in vitro gastric and duodenal digestion models. Residual triacylglycerols and lipolysis products were extracted after 1 h of incubation and analysed by thin layer chromatography. The lipolysis kinetics of almond cells and oil bodies were also investigated using the pH-stat technique. Finally, the potential penetration of pancreatic lipase through the cell wall matrix was investigated using confocal microscopy. Differences in the rates and extent of lipolysis were clearly seen between almond cells and oil bodies, and these differences were observed regardless of the lipase(s) used. These results also showed that almond cell walls that are completely intact limit lipid digestibility, due to an encapsulation mechanism that hinders the diffusion of lipase into the intracellular environment and lipolysis products out of the cells.
Bornhorst, G.M., K.C. Drechsler, C.A. Montoya, S.M. Rutherfurd, P.J. Moughan, R.P. Singh, 2016. Gastric protein hydrolysis of raw and roasted almonds in the growing pig. Food Chem. 211:502-508.
Gastric protein hydrolysis may influence gastric emptying rate and subsequent protein digestibility in the small intestine. This study examined the gastric hydrolysis of dietary protein from raw and roasted almonds in the growing pig as a model for the adult human. The gastric hydrolysis of almond proteins was quantified by performing tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subsequent image analysis. There was an interaction between digestion time, stomach region, and almond type for gastric protein hydrolysis (p<0.05). Gastric emptying rate of protein was a significant (p<0.05) covariate in the gastric protein hydrolysis. In general, greater gastric protein hydrolysis was observed in raw almonds (compared to roasted almonds), hypothesized to be related to structural changes in almond proteins during roasting. Greater gastric protein hydrolysis was observed in the distal stomach (compared to the proximal stomach), likely related to the lower pH in the distal stomach.
Sánchez-González, C., C.J. Ciudad, V. Noé, M. Izquierdo-Pulido, 2015. Health benefits of walnut polyphenols: an exploration beyond their lipid profile. Crit Rev Food Sci Nutr. 57(16):3373-3383.
Walnuts are commonly found in our diet and have been recognized for their nutritious properties for a long time. Traditionally, walnuts have been known for their lipid profile which has been linked to a wide array of biological properties and health-promoting effects. In addition to essential fatty acids, walnuts contain a variety of other bioactive compounds such as, vitamin E and polyphenols. Among common foods and beverages, walnuts represent one of the most important sources of polyphenols, hence, their effect over human health warrants attention. The main polyphenol in walnuts is pedunculagin, an ellagitannin. After consumption, ellagitannins are hydrolyzed to release ellagic acid, which is converted by gut microflora to urolithin A and other derivatives, such as urolithins B, C and D. Ellagitannins possess well known antioxidant and anti-inflammatory bioactivity and several studies have assessed the potential role of ETs against disease initiation and progression, including cancer, cardiovascular and neurodegenerative diseases. The purpose of this review is to summarize current available information relating to the potential effect of walnut polyphenols in health maintenance and disease prevention.
Schlörmann, W., M. Birringer, V. Böhmc, K. Löber, G. Jahreis, S. Lorkowski, A.K. Müller, F. Schöne, M. Glei, 2015. Influence of roasting conditions on health-related compounds in different nuts. Food Chem. Food Chemistry 180:77–85.
Due to their health-beneficial ingredients the consumption of nuts can contribute to a healthy diet. The composition of hazelnuts, almonds, macadamia nuts, pistachios and walnuts regarding health-promoting and potentially harmful compounds was examined before and after roasting under different time and temperature conditions. Fatty acid compositions were not affected by roasting. Malondialdehyde increased with higher roasting temperatures (17-fold in walnuts). Levels of tocopherol isomers were reduced after roasting (α-T: 38%, β-T: 40%, γ-T: 70%) and hydrophilic antioxidant capacity decreased significantly in hazelnuts (1.4-fold), macadamia nuts (1.7-fold) and walnuts (3.7-fold). Increasing roasting temperatures supported the formation of significant amounts of acrylamide only in almonds (1220 μg kg-1). In general, nuts roasted at low/middle temperatures (120–160°C) exhibited best sensory properties. Therefore, desired sensory quality along with a favourable healthy nut composition may be achieved by roasting over a low to medium temperature range.
