The protective effect of a mix ofLactarius deterrimusandCastanea sativaextracts on streptozotocin-induced oxidative stress and pancreatic β-cell death

Abstract

Pancreatic b-cell death or dysfunction mediated by oxidative stress underlies the development and progression of diabetes mellitus. In the present study, we tested extracts from the edible mushroom Lactarius deterrimus and the chestnut Castanea sativa, as well as their mixture (MIX Ld/Cs), for potential beneficial effects on streptozotocin (STZ)-induced pancreatic b-cell death. Analysis of chelating effects, reducing power and radical-scavenging assays revealed strong antioxidant effects of the C. sativa extract and MIX Ld/Cs, while the L. deterrimus extract displayed a weak to moderate effect. The antioxidative effect of the chestnut extract corresponds with the high content of phenolics and flavonoids identified by HPLC analysis. In contrast, the mushroom extract contains relatively small amounts of phenols and flavonoids. However, both extracts, and especially their combination MIX Ld/Cs, increased cell viability after the STZ treatment as a result of a significant reduction of DNA damage and improved redox status. The chestnut extract and MIX Ld/Cs significantly lowered the STZ-induced increases in superoxide dismutase and catalase activities, while the mushroom extract had no impact on the activities of these antioxidant enzymes. However, the L. deterrimus extract exhibited good NO-scavenging activity. Different mechanisms that underlie antioxidant effects of the mushroom and chestnut extracts were discussed. When combined as in the MIX Ld/Cs, the extracts exhibited diverse but synergistic actions that ultimately exerted beneficial and protective effects against STZ-induced pancreatic b-cell death.Key words: Lactarius deterrimus: Castanea sativa: Rin-5F cells: Cytoprotection: Antioxidant activity Reactive oxygen (ROS) and nitrogen (RNS) species are products of normal aerobic metabolism and are continuously produced under physiological conditions. However, when they rise above their physiological concentrations, ROS and RNS are extremely toxic due to their ability to induce protein and DNA damage and lipid peroxidation. Consequently, organisms have developed antioxidant defence systems, i.e. antioxidative enzymes that work in synergy with nonenzymatic antioxidant systems that are produced in cells or ingested through the diet. In healthy individuals, there is a balance between ROS and RNS production and antioxidant defences. An imbalance provoked by either overproduction of reactive species or attenuation of the antioxidative system leads to a process called oxidative stress. Oxidative stress is implicated in the development of many diseases such as CVD, atherosclerosis, neurodegenerative diseases and diabetes mellitus (1) . Diabetes mellitus is a chronic metabolic disorder that continues to present a major health problem worldwide. It is characterised by hyperglycaemia resulting from deficiencies in insulin secretion, insulin action or both. Multiple biochemical pathways and mechanisms for glucose toxicity have been (2) . All of these pathways have in common the formation of ROS that when in excess...

Dietary Supplementation with Chestnut (Castanea sativa) Reduces Abdominal Adiposity in FVB/n Mice: A Preliminary Study

“…Extracts of the chestnut inner shell (C. crenata) reduced oxidative stress in C57BL/6 mice exposed to a high-fat diet [24]. Similar results were reported by Grdović et al [35], who observed that spiny burrs extract of sweet chestnut (C. sativa Mill) reduced DNA damage induced by streptozotocin in pancreatic β-cells, and associated this reduction with the high content of ellagic acid and its derivatives in chestnut. In fact, ellagic acid was already known to reduce DNA damage in Chinese hamster ovary cells through comet assay and cytofluorimetric analyses [36].…”

“…Based on these results, dietary supplementation with edible chestnut does not seem to cause damage to DNA and it may even reduce oxidative DNA damage, in line with the findings of Jovanović et al [25], who showed that spiny burrs extracts of sweet chestnut reduce DNA damage in the liver and kidney cells of diabetic rats. This protective effect may be associated with the antioxidant properties of phenolic compounds in chestnuts [35]. Extracts of the chestnut inner shell (C. crenata) reduced oxidative stress in C57BL/6 mice exposed to a high-fat diet [24].…”

Lentinan protects pancreatic β cells from STZ‐induced damage

“…Cell culture A rat INS-1 cell line, purchased from American Type Culture Collection (ATCC, Manassas, VA, USA), retains physiological characteristics of normal b cells. INS-1 cells (passages [10][11][12][13][14][15][16][17][18][19][20] were grown in RPMI 1640 medium (Hyclone, Logan, UT, USA), containing 6% fetal bovine serum (FBS) (vol./vol. ), 50 lmol/l b -mercaptoethanol, 1 mmol/l sodium pyruvate, 2 mmol/l L-glutamine, 100 U/ml penicillin, 100 lg/ml streptomycin (all from Sigma-Aldrich, St. Louis, MO, USA) and cultured at 37°C in a humidified atmosphere containing 95% air and 5% CO 2 .…”

Treatment of streptozotocin-induced diabetic rats with Castanea sativa and Lactarius deterrimus extracts decreases liver damage by initiating activation of the Akt prosurvival kinase

“…The mushroom L. deterrimus (Ld) was collected in the summer in Istria, Croatia. Cs and Ld extract preparation, their total phenolic and flavonoid contents and qualitative and quantitative analyses were performed using the HPLC/DAD method as described [9,14,15].…”

“…The flowers, fruits, leaves and skins of the sweet chestnut tree from the Fagaceae family, which grows in the Mediterranean region of Europe, have been widely used in folk medicine for treating various respiratory diseases [6,7]. Recent investigations have shown that the extract of the chestnut Castanea sativa possesses antiviral effects and the ability to lower oxidative stress and DNA damage [8,9]. Recent findings suggest that edible mushrooms are efficient antioxidants, possessing a radical scavenging activity whose antioxidant properties are effective in diabetes management [10].…”