Antiatherogenic activity of extracts of Argania spinosa L. pericarp: beneficial effects on lipid peroxidation and cholesterol homeostasisThis article is one of a selection of papers published in this special issue (part 1 of 2) on the Safety and Efficacy of Natural Health Products.

2007 ◽  
Vol 85 (9) ◽  
pp. 918-927 ◽  
Author(s):  
Hicham Berrougui ◽  
Mounia Cherki ◽  
Geremy Abdull Koumbadinga ◽  
Maxim Isabelle ◽  
Jasmin Douville ◽  
...  

Prevention of lipoprotein oxidation by natural compounds may prevent atherosclerosis via reducing early atherogenesis. In this study, we investigated for the first time the beneficial properties of methanolic extract of argania pericarp (MEAP) towards atherogenesis by protecting human low-density lipoprotein (LDL) against oxidation while promoting high-density lipoprotein (HDL)-mediated cholesterol efflux. By measuring the formation of malondialdehyde (MDA) and conjugated diene as well as the lag phase and the progression rate of lipid peroxidation, the MEAP was found to possess an inhibitory effect. In addition, MEAP reduced the rate of disappearance of α-tocopherol as well as the apoB electrophoretic mobility in a dose-dependent manner. These effects are related to the free radical scavenging and copper-chelating effects of MEAP. In terms of cell viability, MEAP has shown a cytotoxic effect (0–40 μg/mL). Incubation of3H-cholesterol-loaded J774 macrophages with HDL in the presence of increasing concentrations of MEAP enhanced HDL-mediated cholesterol efflux independently of ABCA1 receptor pathways. Our findings suggest that argania seed pericarp provides a source of natural antioxidants that inhibit LDL oxidation and enhance cholesterol efflux and thus can prevent development of cardiovascular diseases.

1996 ◽  
Vol 320 (2) ◽  
pp. 373-381 ◽  
Author(s):  
Suzanne E. STAIT ◽  
David S. LEAKE

Ascorbate at concentrations of 60–100 µM inhibits the modification of freshly prepared low-density lipoprotein (LDL) by macrophages. With ‘moderately oxidized’ LDL (produced by prolonged storage in a refrigerator), however, ascorbate does not inhibit LDL modification by macrophages and actually modifies the LDL itself in the absence of macrophages [Stait and Leake (1994) FEBS Lett. 341, 263–267]. We have now shown that dehydroascorbate can modify both ‘fresh’ LDL and moderately oxidized LDL in a dose-dependent manner to increase its uptake by macrophages. The modification of moderately oxidized LDL by ascorbate and dehydroascorbate or of ‘fresh’ LDL by dehydroascorbate is dependent on the presence of iron or copper. In ‘fresh’ LDL, ascorbate inhibited conjugated-diene formation by copper. In moderately oxidized LDL, the number of conjugated dienes present was decreased rapidly in the presence of copper and ascorbate. Dehydroascorbate decreased the lag phase and increased the rate of copper-induced conjugated-diene formation in ‘fresh’ LDL (although in some experiments it inhibited the formation of conjugated dienes). The ascorbate-modified moderately oxidized LDL was taken up by macrophages by their scavenger receptors, as the uptake was inhibited by polyinosinic acid or fucoidan. Ascorbate and dehydroascorbate therefore have the potential to increase LDL oxidation under certain conditions, but whether or not they do so in vivo is unknown.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Omodesola O. Ogunruku ◽  
Ganiyu Oboh ◽  
Ayokunle O. Ademosun

Background. This study sought to investigate antioxidant capacity of aqueous extracts of two pepper varieties (Capsicum annuumvar.accuminatum(SM) andCapsicum chinense(RO)) and their inhibitory effect on acetylcholinesterase and butyrylcholinesterase activities.Methods. The antioxidant capacity of the peppers was evaluated by the 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging ability and ferric reducing antioxidant property. The inhibition of prooxidant induced lipid peroxidation and cholinesterase activities in rat brain homogenates was also evaluated.Results. There was no significant difference (P>0.05) in the total phenol contents of the unripe and ripeCapsicumspp. extracts. Ripe and unripe SM samples had significantly higher (P<0.05) ABTS*scavenging ability than RO samples, while the ripe fruits had significantly higher (P<0.05) ferric reducing properties in the varieties. Furthermore, the extracts inhibited Fe2+and quinolinic acid induced lipid peroxidation in rats brain homogenates in a dose-dependent manner. Ripe and unripe samples from SM had significantly higher AChE inhibitory abilities than RO samples, while there was no significant difference in the BuChE inhibitory abilities of the pepper samples.Conclusion. The antioxidant and anticholinesterase properties ofCapsicumspp. may be a possible dietary means by which oxidative stress and symptomatic cognitive decline associated with neurodegenerative conditions could be alleviated.


Author(s):  
Ganiyu Oboh ◽  
Veronica O. Odubanjo ◽  
Fatai Bello ◽  
Ayokunle O. Ademosun ◽  
Sunday I. Oyeleye ◽  
...  

AbstractAvocado pear (The inhibitory effects of extracts on AChE and BChE activities and antioxidant potentials (inhibition of FeThe extracts inhibited AChE and BChE activities and prooxidant-induced TBARS production in a dose-dependent manner, with the seed extract having the highest inhibitory effect and the leaf extract exhibiting higher phenolic content and radical scavenging abilities, but lower Fe chelation ability compared with that of the seed. The phytochemical screening revealed the presence of saponins, alkaloids, and terpenoids in both extracts, whereas the total alkaloid profile was higher in the seed extract than in the leaf extract, as revealed by GC-FID.The anti-cholinesterase and antioxidant activities of avocado leaf and seed could be linked to their phytoconstituents and might be the possible mechanisms underlying their use as a cheap and natural treatment/management of AD. However, these extracts should be further investigated in vivo.


2019 ◽  
Author(s):  
Linda S. May-Zhang ◽  
Valery Yermalitsky ◽  
John T. Melchior ◽  
Jamie Morris ◽  
Keri A. Tallman ◽  
...  

ABSTRACTThe lipid aldehyde 4-oxo-2-nonenal (ONE) derived from peroxidation of n-6 polyunsaturated fatty acids and generated in parallel to 4-hydroxynonenal (HNE) is a highly reactive protein crosslinker. Crosslinking of proteins in high-density lipoprotein (HDL) by lipid peroxidation products causes HDL dysfunction and contributes to atherogenesis. While HNE is relatively well studied, the relevance of ONE in atherosclerosis and in modifying HDL has not been examined. In the present study, we found a significant increase in ONE-ketoamide (lysine) adducts in HDL derived from patients with familial hypercholesterolemia (FH) (1620 ± 985.4 pmol/mg) compared to healthy controls (664 ± 219.5 pmol/mg). ONE crosslinked apoA-I on HDL at a concentration of >3 mol ONE per 10 mol apoA-I (0.3 eq), which is 100-fold lower than HNE but comparable to the potent protein crosslinker, isolevuglandin. ONE-modified HDL partially inhibited the ability of HDL to protect against LPS-induced TNFα and IL-1β mRNA expression in murine macrophages. At 3 eq., ONE dramatically decreased the ability of apoA-I to exchange from HDL, from ~46.5% to only ~18.4% (P<0.001). Surprisingly, ONE-modification of HDL or apoA-I did not alter macrophage cholesterol efflux capacity. LC/MS/MS analysis showed modification of Lys12, Lys23, Lys96, and Lys226 of apoA-I by ONE-ketoamide adducts. Compared to other dicarbonyl scavengers, pentylpyridoxamine (PPM) was most efficacious at blocking ONE-induced protein crosslinking in HDL. Our studies show that ONE HDL adducts are elevated in FH who have severe hypercholesterolemia and atherosclerosis and causes HDL dysfunction. We demonstrate the use of PPM in preferentially scavenging ONE in biological systems.


2021 ◽  
Vol 913 (1) ◽  
pp. 012093
Author(s):  
U Fitrotin ◽  
N Hilmiati ◽  
Mardiana ◽  
Y Triguna ◽  
A Surahman ◽  
...  

Abstract Preparation process for meniran (Phillantus urinaria) functional drink (MFD) influences its antioxidant activity. This research aims to understand the phenolic content, DPPH Radical Scavenging Activity (RSA), and LDL oxidation of MFD through various preparation processes. Those preparation processes included soaking fresh meniran (SFM), boiling fresh meniran for 5 minutes (BFM5’), boiling fresh meniran for 10 minutes (BFM10’), and soaking dried meniran (DM). The phenolic content was determined with Folin–Ciocalteu, antioxidant activity was assessed using DPPH and TBARS assay with LDL as the oxidation substrate. An antioxidant references in this research used ascorbic acid. The phenolic content in methods of SFM, BFM5’, BFM10’ and DM were 122±0.022, 182±0.043, 192 ±0.03, and 117 ±0.019 mg GAE/g of meniran respectively. Meanwhile, the DPPH RSA of SFM, BFM5’, BFM10’ and DM accounted for 82.18±0.35, 86.19±0.53, 86.75±0.64 and 69.96% respectively. As comparison, the DPPH RSA of ascorbic acid 50 ppm is 75.65±0.82%. At the same time the optimum inhibition of TBARS formation from BFM5’ and BFM10’ methods were 45.83 % and 48.66%, with MDA concentration in human LDL accounted for 38.30±2.39 and 36.30±1.82 nmol MDA/mg protein, respectively. As comparison, MDA concentration in human LDL added with ascorbic acid 25 ppm accounted for 41.35±2.41 nmol MDA/mg protein. In contrast, the control human LDL was 70.70±2.35 nmol MDA/mg protein. This study concludes that the BFM5’ and BFM10’ methods showed the highest antioxidant properties compared to other methods. All methods showed that MFD extract in concentration more than 25 ppm increased the concentration of MDA in human LDL. Therefore, to produce meniran functional drink in optimum antioxidant properties is best by using BFM5’ and BFM10’ preparation methods in meniran concentration of not more than 25 ppm.


2021 ◽  
Vol 18 (7) ◽  
pp. 1493-1497
Author(s):  
Lai-zeng Yu ◽  
Xue-peng Zhang ◽  
Ying-xin Wang

Purpose: To investigate the effect of Polygonatum sibiricum extract (PSE) on streptozotocin-induced diabetic rats. Methods: PSE was obtained by steeping the dried Polygonatum sibiricum in water at 60 oC three times, each for 1 h, before first drying in an oven at 100C and then freeze-drying the final extract, thus obtained. Diabetic model rats were prepared by a single intraperitoneal injection of a freshly prepared solution of streptozotocin (50 mg/kg). The rats were randomly divided into 6 groups of ten rats each: negative control, normal control, reference (glibenclamide1 mg/kg) as well as PSE groups, (35, 70 and 140 mg/kg). Blood glucose and plasma insulin levels were measured to determine antihyperglycemic effect. Oxidative stress was evaluated in liver and kidney by their antioxidant markers, viz, lipid peroxidation (LPO), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx) and catalase (CAT). Blood serum levels of creatinine and urea were determined in both diabetic control and treated rats. Results: Compared with diabetic rats, oral administration of PSE at a concentration of 120 mg/kg daily for 30 days showed a significant decrease in fasting blood glucose (118.34 ± 3.29 mg/dL) (p < 0.05) and increased insulin level (12.86± 0.62 uU/mL, p < 0.05). Furthermore, it significantly reduced biochemical parameters (serum creatinine, 0.83 ±0.21 mg/dL, p < 0.05) and serum urea (43.26±1.42 mg/dL, p < 0.05). Conclusion: The results suggest that PSE may effectively normalize impaired antioxidant status in streptozotocin-induced diabetes in a dose-dependent manner. Thus, PSE has a protective effect against lipid peroxidation by scavenging free radicals, restoration of insulin function, and reduction of the incidence of complications.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Mohammad Azizur Rahman ◽  
Noorlidah Abdullah ◽  
Norhaniza Aminudin

Oxidation of low-density lipoprotein (LDL) has been strongly suggested as the key factor in the pathogenesis of atherosclerosis. Mushrooms have been implicated in having preventive effects against chronic diseases due especially to their antioxidant properties. In this study,in vitroinhibitory effect ofHericium erinaceuson LDL oxidation and the activity of the cholesterol biosynthetic key enzyme, 3-hydroxy-3-methyl glutaryl coenzyme A (HMG Co-A) reductase, was evaluated using five liquid-liquid solvent fractions consisting of methanol : dichloromethane (M : DCM), hexane (HEX), dichloromethane (DCM), ethyl acetate (EA), and aqueous residue (AQ). The hexane fraction showed the highest inhibition of oxidation of human LDL as reflected by the increased lag time (100 mins) for the formation of conjugated diene (CD) at 1 µg/mL and decreased production (68.28%, IC500.73 mg/mL) of thiobarbituric acid reactive substances (TBARS) at 1 mg/mL. It also mostly inhibited (59.91%) the activity of the HMG Co-A reductase at 10 mg/mL. The GC-MS profiling of the hexane fraction identified the presence of myconutrients:inter alia, ergosterol and linoleic acid. Thus, hexane fraction ofHericium erinaceuswas found to be the most potentin vitroinhibitor of both LDL oxidation and HMG Co-A reductase activity having therapeutic potential for the prevention of oxidative stress-mediated vascular diseases.


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