Antioxidative and radical scavenging effects of olive cake extract

Effects of a Phytogenic Supplement Containing Olive By-Product and Green Tea Extracts on Growth Performance, Lipid Metabolism, and Hepatic Antioxidant Capacity in Largemouth Bass (Micropterus salmoides) Fed a High Soybean Meal Diet

A 10-week growth trial was conducted to investigate the effects of a phytogenic feed additive (PFA) containing olive by-products and green tea extracts supplemented to a reduced fishmeal/high soybean meal diet on the growth performance, hepatic antioxidant capacity, lipid metabolism, and liver health of largemouth bass (Micropterus salmoides). Three experimental diets were tested: (1) a control high fishmeal (40%) and low soybean meal (15.57%) diet (named HFM), (2) a reduced fishmeal (30%) and high soybean meal (30.97%) diet (named HSB), and (3) a HSB diet supplemented with the PFA at 500 mg/kg (named HSB+P). Each diet was assigned to four replicate tanks, each containing 30 largemouth bass (initial body weight, IBW = 48.33 ± 0.01 g). The results showed that increasing the soybean meal content in the diet did not negatively affect growth performance, whereas supplementation with PFA significantly increased weight gain and specific growth rate of largemouth bass compared to both HFM and HSB groups. Reducing fishmeal and increasing soybean meal in the diet caused oxidative stress with a higher content of ROS in the liver. However, the hepatic antioxidant capacity was enhanced, with reduced ROS and increased GSH-Px levels in the HSB+P group. Moreover, the decrease of plasma TG, LDL-C, and LDL-C/TC, and downregulation of lipogenesis and cholesterol synthesis gene expression in liver, indicated that supplementation with the PFA improved fish lipid metabolism. Protein retention efficiency was also significantly increased in largemouth bass fed the diet with PFA supplementation, which regulated (enhanced) AKT-mTOR phosphorylation. These results clearly indicated that a PFA containing olive by-product and green tea extracts can positively improve growth performance, protein retention efficiency, antioxidant capacity, and lipid metabolism of largemouth bass fed a reduced fishmeal/high soybean meal diet.

Antioxidant Activity of Moringa oleifera and Olive Olea europaea L. Leaf Powders and Extracts on Quality and Oxidation Stability of Chicken Burgers

Oxidation is the main cause of quality deterioration in meat-based foods, such as burgers. Antioxidants inhibit the oxidation process; recently, natural antioxidants have gained interest, due to safety concerns. In this study, the effects of leaf powder and crude extracts of both Moringa oleifera and olive in chicken burgers were studied for their antioxidant potential in preventing fat oxidation during storage. Antioxidant activities were evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl). The results showed the highest DPPH radical scavenging with IC50 values of 2.397 ± 0.10 mg/mL in the Moringa leaf. Total phenolic content (TPC) was crude olive extract > crude Moringa extract > olive leaf > Moringa leaf. The total flavonoid content (TFC) was significantly higher in the olive leaf and its crude extract than in the Moringa leaf and its crude extract. The pH, total volatile nitrogen, and sensory properties were affected by the addition of olive and Moringa (leaf and crude extracts) to chicken burgers refrigerated for 20 days. The addition of Moringa and olive leaf powder decreased lipid oxidation and PV after 10 days of storage. In general, Moringa and olive leaf treatments slowed the deterioration of meat, suggesting their use as preservatives to extend the shelf-life of chicken burgers.

Olive oil cake extract stabilizes the physiological condition of lipopolysaccharide-challenged piglets by reducing oxidative stress and inflammatory responses and modulating the ileal microbiome

Olives are a rich source of compounds with antioxidant and anti-inflammatory activities. This study was designed to investigate whether a standardized olive cake extract was able to alleviate oxidative stress, inflammation and intestinal villus damage in a model of lipopolysaccharide (LPS)-challenged piglets. Thirty weaned piglets (6.9 ± 0.9 kg) were assigned to five groups using a randomized complete block design. Piglets were fed a basal diet before intraperitoneal (i.p.) injection of physiological saline (C); fed a basal diet alone (CL) or fed a basal diet plus an olive cake extract (OL), antibiotics (AL), or olive cake extract plus antibiotics (OAL) before i.p. injection of LPS. The feeding period lasted for 2 weeks. Piglets were euthanized 4 h after the LPS injection. Systemic oxidative and inflammatory status and intestinal morphology were evaluated. LPS challenge significantly lowered the serum levels of GSH-Px, SOD and ALB and increased the serum concentration of MDA, NO, LDH, ALT, AST, TNF-α, IL-6, DAO and D-xylose (P < 0.05), as extracted from the comparison of piglets in the C and CL groups. Intestinal morphology was altered in the duodenum and ileum, displaying that the CL group had significantly lower villus height (VH), higher crypt depth (CD) and lower VH/CD compared with the control group (P < 0.05). Moreover, feed supplementation was able to partially mitigate the negative effects of LPS challenge in all groups (OL, AL, and OAL), as evidenced by the significantly increased serum levels of GSH-Px, SOD, ALB and IL-10 and decreased concentration of MDA, NO, LDH, ALT, AST, TNF-α, IL-6, DAO and D-xylose, compared with the CL group (P < 0.05). Alterations in intestinal morphology were also prevented and the OL, AL, and OAL groups had significantly lower CD and higher VH/CD compared with the CL group (P < 0.05), both in the ileum and duodenum. Furthermore, the positive effect in the relative abundance of intestinal Lactobacillus and Clostridium at the genus level was also observed for the OL group compared to the CL group. In summary, dietary supplementation with an olive cake extract stabilized the physiological condition of piglets subjected to an acute LPS challenge by reducing oxidative stress and the inflammatory status, improving intestinal morphology and increasing the abundance of beneficial intestinal bacteria. This trial was registered at Zhejiang University (http://www.lac.zju.edu.cn) as No. ZJU20170529.

Impact of Fermented or Enzymatically Fermented Dried Olive Pomace on Growth, Expression of Digestive Enzyme and Glucose Transporter Genes, Oxidative Stability of Frozen Meat, and Economic Efficiency of Broiler Chickens

The use of dried olive pomace as complementary energy sources in poultry feed is still limited due to its low protein and high fiber contents. Bioconversion of olive pomace through solid-state fermentation with or without exogenous enzymes is considered as a trial for improving its nutritional value. This study aimed to evaluate the effects of fermented olive pomace with or without enzymatic treatment on the growth, modulations of genes encoding digestive enzymes and glucose transporters, meat oxidative stability, and economic efficiency of broiler chickens. A total of 1400 day-old broiler chicks (Ross 308) were randomly allocated to seven dietary treatments with 10 replicates of 20 birds/replicate. Treatments included control (basal corn-soybean diet) and other six treatments in which basal diet was replaced by three levels (7.5, 15, and 30%) of fermented olive pomace (FOPI) or enzymatically fermented olive pomace (FOPII) for 42 days. The highest body weight gain was observed in groups fed 7.5 and 15% FOPII (increased by 6.6 and 12.5%, respectively, when compared with the control group). Also, feeding on 7.5 and 15% FOPII yielded a better feed conversion ratio and improved the digestibility of crude protein, fat, and crude fiber. The expression of the SGLT-1 gene was upregulated in groups fed FOPI and FOPII when compared with the control group. Moreover, the expression of the GLUT2 gene was elevated in groups fed 7.5 and 15% FOPII. By increasing the levels of FOPI and FOPII in diets, the expression of genes encoding pancreatic AMY2A, PNLIP, and CCK was upregulated (p < 0.05) when compared with the control. Fat percentage and cholesterol content in breast meat were significantly reduced (p < 0.05) by nearly 13.7 and 16.7% in groups fed FOPI and FOPII at the levels of 15 and 30%. Total phenolic and flavonoid contents in breast meat were significantly increased in groups fed 15 and 30% FOPI and FOPII when compared with the control group and even after a long period of frozen storage. After 180 days of frozen storage, the inclusion of high levels of FOP significantly increased (p < 0.05) the levels of glutathione peroxide and total superoxide dismutase and meat ability to scavenge free radical 1,1-diphenyl-2-picrylhydrazyl. Furthermore, the highest net profit and profitability ratio and the lowest cost feed/kg body gain were achieved in groups fed 7.5 and 15% of FOPII, respectively. The results of this study indicated that dietary inclusion of 15% FOPII could enhance the growth performance and economic efficiency of broiler chickens. Moreover, a higher inclusion level of FOPI or FOPII could enhance the quality and increase the oxidative stability of frozen meat and extend the storage time.

Investigations of Olive Oil Industry By-Products Extracts with Potential Skin Benefits in Topical Formulations

The by-products of olive oil industry are a major ecological issue due to their phenolic content, highly toxic organic load, and low pH. However, they can be recovered and reused, since their components have antioxidant, anti-inflammatory, and photoprotector properties. In this work, oil-in-water creams containing three different olive oil industry by-products extracts were produced without the use of organic solvents. First, the extracts were thoroughly characterized in vitro for cytotoxicity, inhibition of skin enzymes, and antioxidant and photoprotection capacities. Safety studies were then performed, including ocular and skin irritation tests, ecotoxicity evaluation, and in vivo Human Repeat Insult Patch Test. The results obtained in this initial characterization supported the incorporation of the extracts in the cream formulations. After preparation, the creams were characterized for their organoleptic, physicochemical, droplet size and rheological properties, and microbial contamination. The results showed that all formulations were semi-solid creams, with stable pH, compatible with the skin, without microbial contamination, and with the expected droplet size range. The rheological analysis showed shear-thinning behavior with yield stress, with the viscosity decreasing with increasing shear rate. The oscillatory results suggest that the creams have a strong network structure, being easily rubbed into the skin. Finally, compatibility, acceptability and antioxidant efficacy were evaluated in vivo, in human volunteers. No adverse reactions were observed after application of the formulations on skin and the cream with the highest concentrations of phenolic compounds showed the highest antioxidant efficiency. In conclusion, the results suggest that olive oil industry by-products extracts have valuable properties that favor their re-use in the cosmetic industry. The example presented here showed their successful incorporation into creams and their impact in these formulations' appearance, pH, and rheological performance, as well as their in vivo compatibility with skin and antioxidant efficiency.

Phytochemical analysis of olive flowers' hydroalcoholic extract and in vitro evaluation of tyrosinase, elastase and collagenase inhibition activity

Olea europaea L. is historically one of the most important trees of the Mediterranean countries. Increasing scientific interest regarding its fruits, leaves and olive oil has led to the elucidation of several phytochemical and biological characteristics. However, the phytochemical and biological studies regarding olive flowers remain limited. The aim of the present study was the phytochemical characterization of olive flowers' hydroalcoholic extract from Greek variety Lianolia, the effective isolation of the major secondary metabolites and evaluation of their inhibition activity against tyrosinase, elastase and collagenase. UPLC-HRMS/MS analysis was used to investigate the chemical composition of hydroalcoholic extract resulting in the identification of sixty-three secondary metabolites witch mainly belong to phenilethanoids, triterpenoids, flavonoids and secoiridoids. The orthogonial combination of Centrifugal Partition Chromatography and preparative HPLC in the same purification process led to the isolation of nine major compounds of the extract including two triterpenic acids, two flavonoid glycosides and five secoiridoid derivatives. From them, oleofloside A and oleofloside B are new natural products. Although, the hydroalcoholic extract and isolated secoiridoids exhibited weak or no inhibition activity towards tyrosinase and elastase, they exhibit remarkable anti-collagenase activity with 2΄-ethoxyoleuropein being the most active compound.

Scavenging activity and mechanism study of ferulic acid against reactive carbonyl species acrolein

Acrolein, known as one of the most common reactive carbonyl species, is a toxic small molecule affecting human health in daily life. This study is focused on the scavenging abilities and mechanism of ferulic acid and some other phenolic acids against acrolein. Among the 13 phenolic compounds investigated, ferulic acid was found to have the highest efficiency in scavenging acrolein under physiological conditions. Ferulic acid remained at (3.04±1.89)% and acrolein remained at (29.51±4.44)% after being incubated with each other for 24 h. The molecular mechanism of the detoxifying process was also studied. Detoxifying products, namely 2-methoxy-4-vinylphenol (product 21) and 5-(4-hydroxy-3-methoxyphenyl)pent-4-enal (product 22), were identified though nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS), after the scavenging process. Ferulic acid showed significant activity in scavenging acrolein under physiological conditions. This study indicates a new method for inhibiting damage from acrolein.

Effects of Dried Olive Pulp Dietary Supplementation on Quality Characteristics and Antioxidant Capacity of Pig Meat

Olive pulp belongs to agro-industrial by-products, and its addition into livestock diets generally result in neutral or positive effects on performance. However, the data concerning the effects of olive by-products on pork meat characteristics are scarce. The aim of this preliminary study was therefore to examine the effects of dried olive pulp (DOP) dietary supplementation on quality parameters and oxidative stability of pig meat. Twenty finishing pigs were allocated to two groups: C that was provided with a control diet, and DOP that was fed with an isonitrogenous and isoenergetic diet supplemented with dried olive pulp at the level of 50 g/kg or 5%. As indicated, cold carcass weight, pH, lightness, redness, cooking loss, and tenderness were not influenced by DOP inclusion. Only meat yellowness (a*) was significantly decreased in DOP meat samples. Moreover, meat oxidation values tended to decrease in the DOP group after one day, but no further differences were observed after four, six, and eight days of refrigerated storage. It can be concluded that DOP dietary supplementation could be recommended as a feasible approach, especially in the Mediterranean region to reduce diet formulation costs, while no significant side effects on pork meat quality are observed.

Immuno-physiological and antioxidant responses of Siberian sturgeon (Acipenser baerii) fed with different levels of olive pomace

Nowadays, use of the natural plant derivatives as an immunostimulant in aquaculture is becoming more useful than antibiotics which are destructive to target animals, consumers, and the environment. The present study aimed to evaluate the efficacy of dietary substitution of wheat flour at 2, 5, 7.5, and 10% of olive pomace (OP₂, OP₅, OP_7.5, and OP₁₀) in some immune-physiological and antioxidant variables of yearling Siberian sturgeon (Acipenser baerii) weighing 165 ± 6.8 g at 19.1 ± 1.52 °C for 56 days. Fifteen fish per tank were randomly accommodated in triplicates per treatment and the control group was also included. No significant difference was seen in hematological indices including red blood cells (RBS) and immunocompetent cell population sizes among the treated groups (P > 0.05). Also, malondialdehyde (MDA) activity and superoxide dismutase (SOD) in serum remained unaffected in different treatments (P > 0.05). Total protein (TP), high-density lipoprotein (HDL), catalase (CT), and lysozyme were affected by dietary OP levels (P < 0.05), and the highest value was observed at the OP₅ diet, but no influence was seen in serum IgM by OP. These data show that application of olive pomace as a partial substitute of wheat flour in the diet of Siberian sturgeon is feasible with stimulatory and antioxidant functions.

The in vitro Immunomodulatory Activity of Oleuropein, a Secoiridoid Glycoside from Olea europaea L

Oleuropein, a secoiridoid glycoside, is a potential antioxidant and antimicrobial agent. The aim of the present study was to investigate the in vitro effects of oleuropein and Olea europaea extracts on unstimulated lymphocytes. Oleuropein did not produce any significant cytotoxic effects on lymphocytes. On the contrary, it had a stimulatory effect, and was capable of inducing and maintaining high proliferation rates in lymphocytes. The stimulatory effects of oleuropein and extracts were concentration-dependent with a range of median stimulatory concentration 1 mM at 48 h. The cytotoxicity effect of oleuropein and extracts increased with time resulting in a greater cytotoxic effect on already-stimulated lymphocytes at 96 h even though dose dependence was not demonstrated. Morphological observations showed that oleuropein and extracts induced blastogenesis similar to that of phytohaemagglutinin (PHA). In fact, from lymphocyte activation studies, oleuropein exhibited a high degree of lymphocyte aggregation, which is an indicator of cell activation and proliferation.

Phytochemical analysis and antidiabetic potential of Elaeagnus umbellata (Thunb.) in streptozotocin-induced diabetic rats: pharmacological and computational approach

Background

The fruit of Elaeagnus umbellata has high medicinal values and is an excellent source of phytochemicals. This study was aimed to evaluate the antioxidant, enzyme inhibitory and antidiabetic potential of Elaeagnus umbellata.

Methods

The antioxidant potential of the crude extract and subfractions of E. umbellata fruit were determined using DPPH (2, 20-diphenyl-1-picrylhydrazyl) and ABTS (2, 2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid) assays. The enzyme inhibitory potentials of extracts against α-amylase and α-glucosidase enzymes were also determined. The in vivo anti-hyperglycemic effects of the extract in STZ-induced type 2 diabetes were determined using Sprague Dawley adult rats. HPLC system (Agilent 1260) was used for the identification of bioactive compounds present in extracts. Molecular docking was used to identify and compare the interaction between the compounds (active constituents) and standard inhibitor acarbose with the α-amylase and α-glucosidase active sites.

Results

The chloroform, ethyl acetate, and butanol fractions showed significant antioxidant potential with IC₅₀ values of 40, 45 and 60 μg/mL against DPPH and 57, 70 and 120 μg/mL against ABTS free radicals respectively. The chloroform and ethyl acetate were highly active against α-amylase and α-glucosidase (IC₅₀ values 58 and 200 μg/ml against α-amylase 60 and 140 μg/ml against α-glucosidase. The crude extract, chloroform, and ethyl acetate fractions were more potent in controlling the hyperglycemia in STZ-induced type 2 diabetes in rats and considerable reduction of glucose level was observed compared to the non-treated group. Furthermore, the extracts were also found useful in controlling the secondary complications associated with type 2 diabetes mellitus which was evident from the observed substantial reduction in the blood level of serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, alkaline phosphatase, total cholesterol, low-density lipoproteins, and triglycerides. The molecular docking approach indicated the favorable inhibitory interaction between the docked compounds and the active sites of the α-amylase and α-glucosidase. All docked compounds occupied the same binding site as occupied by acarbose.

Conclusion

It was concluded that E. umbellata can be used in the treatment of type 2 diabetes and oxidative stress. The extracts were also found to be effective in relieving the secondary complications associated with type 2 diabetes.

Graphical abstract

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2381-8) contains supplementary material, which is available to authorized users.

Optimization of ultrasonic circulating extraction of samara oil from Acer saccharum using combination of Plackett-Burman design and Box-Behnken design

In this study, ultrasonic circulating extraction (UCE) technique was firstly and successfully applied for extraction of samara oil from Acer saccharum. The extraction kinetics were fitted and described, and the extraction mechanism was discussed. Through comparison, n-hexane was selected as the extraction solvent, the influence of solvent type on the responses was detailedly interpreted based on the influence of their properties on the occurrence and intensity of cavitation. Seven parameters potentially influencing the extraction yield of samara oil and content of nervonic acid, including ultrasound irradiation time, ultrasound irradiation power, ultrasound temperature, liquid-solid ratio, soaking time, particle size and stirring rate, were screened through Plackett-Burman design to determine the significant variables. Then, three parameters performed statistically significant, including liquid-solid ratio, ultrasound irradiation time and ultrasound irradiation power, were further optimized using Box-Behnken design to predict optimum extraction conditions. Satisfactory yield of samara oil (11.72±0.38%) and content of nervonic acid (5.28±0.18%) were achieved using the optimal conditions. 1% proportion of ethanol in extraction solvent, 120°C of drying temperature and 6.4% moisture were selected and applied for effective extraction. There were no distinct differences in the physicochemical properties of samara oil obtained by UCE and Soxhlet extraction, and the samara oil obtained by UCE exhibited better antioxidant activities. Therefore, UCE method has enormous potential for efficient extraction of edible oil with high quality from plant materials.

Phenolic content and antioxidant activity of olive by-products and antioxidant film containing olive leaf extract

The antioxidant activity of olive leaf (OL) and cake (OC) extracts with different solvents was evaluated. 70% of aqueous ethanol extract of OL was chosen as the most antioxidant extract based on antiradical activity (DPPH) (95.4±0.3%) and oxygen radical absorbance capacity (ORAC) (0.82±0.07g equivalent Trolox per g of solution) assays. This OL extract was incorporated in two multilayer materials consisting of (i) polyethylene/polyethylene (PE/PE) film and (ii) polyethylene/paper (PE/P). These multilayers were exposed to a gas stream enriched in free radicals to evaluate the scavenging capacity of both materials. PE/PE film exhibited the highest scavenging activity of free radicals (78.8%). Migration of the phenolic compounds from olive by-products into two simulants was performed and demonstrated a non-migrating behavior. The limits of detection and quantification for oleuropein were 0.5μgkg(-1) and 1.7μgkg(-1) and for Luteolin-7-O-glucoside 1.3μgkg(-1) and 4.3μg kg(-1) respectively.

Olive Mill Waste Extracts: Polyphenols Content, Antioxidant, and Antimicrobial Activities

Natural polyphenols extracts have been usually associated with great bioactive properties. In this work, we investigated in vitro antioxidant and antimicrobial potential of the phenolic olive mill wastewater extracts (OWWE) and the olive cake extracts (OCE). Using the Folin Ciocalteux method, OWWE contained higher total phenol content compared to OCE (8.90 ± 0.728 g/L versus 0.95 ± 0.017 mg/g). The phenolic compounds identification was carried out with a performance liquid chromatograph coupled to tandem mass spectrometry equipment (HPLC-ESI-MS). With this method, a list of polyphenols from OWWE and OCE was obtained. The antioxidant activity was measured in aqueous (DPPH) and emulsion (BCBT) systems. Using the DPPH assay, the results show that OWWE was more active than OCE and interestingly the extracts originating from mountainous areas were more active than those produced from plain areas (EC₅₀ = 12.1 ± 5.6 μg/mL; EC₅₀ = 157.7 ± 34.9 μg/mL, resp.). However, when the antioxidant activity was reversed in the BCBT, OCE produced from plain area was more potent than mountainous OCE. Testing by the gel diffusion assay, all the tested extracts have showed significant spectrum antibacterial activity against Staphylococcus aureus, whereas the biophenols extracts showed more limited activity against Escherichia coli and Streptococcus faecalis.

High impact biowastes from South European agro-industries as feedstock for second-generation biorefineries

Availability of bio-based chemicals, materials and energy at reasonable cost will be one of the forthcoming issues for the EU economy. In particular, the development of technologies making use of alternative resources to fossil fuels is encouraged by the current European research and innovation strategy to face the societal challenge of natural resource scarcity, fossil resource dependence and sustainable economic growth. In this respect, second- generation biorefineries, i.e. biorefineries fed with biowastes, appear to be good candidates to substitute and replace the present downstream processing scheme. Contrary to first-generation biorefineries, which make use of dedicated crops or primary cultivations to achieve such a goal, the former employ agricultural, industrial, zootechnical, fishery and forestry biowastes as the main feedstock. This leaves aside any ethical and social issue generated by first-generation approaches, and concomitantly prevents environmental and economical issues associated with the disposal of the aforementioned leftovers. Unfortunately, to date, a comprehensive and updated mapping of the availability and potential use of bioresources for second-generation biorefineries in Europe is missing. This is a lack that severely limits R&D and industrial applications in the sector. On the other hand, attempts at valorizing the most diverse biowastes dates back to the nineteenth century and plenty of information in the literature on their sustainable exploitation is available. However, the large majority of these investigations have been focused on single fractions of biowastes or single steps of biowaste processing, preventing considerations on an integrated and modular (cascade) approach for the whole valorization of organic leftovers. This review aims at addressing these issues by gathering recent data on (a) some of the main high-impact biowastes located in Europe and in particular in its Southern part, and (b) the bio-based chemicals, materials and fuels that can be produced from such residues. In particular, we focused on those key compounds referred to as "chemical platforms", which have been indicated as fundamental to generate the large majority of the industrially relevant goods to date.

Physiological investigations on the effect of olive and rosemary leaves extracts in male rats exposed to thioacetamide

Physiologically, it is known that thioacetamide (TAA) toxicity is generally associated with hepatic fibrosis induction, complicated metabolic disorders and health problems. The capability of extracts of olive and rosemary leaves to attenuate the severe physiological disturbances induced by thioacetamide (TAA) intoxication in male rats has been evaluated. Healthy male Wistar rats were used in the present study and were divided randomly into eight groups. Rats of the first group were served as normal control. Rats of the second group were administrated with TAA. Rats of the third, fourth and fifth groups were exposed to TAA plus olive leaves extract, TAA plus rosemary leaves extract and TAA plus olive and rosemary leaves extracts respectively. The sixth, seventh and eighth groups were supplemented with olive leaves extract, rosemary leaves extract, and olive and rosemary leaves extracts respectively. After 12 weeks of experimental treatments, the levels of serum glucose, total protein, albumin and high density lipoprotein cholesterol were significantly decreased, while the levels of triglycerides, cholesterol, low density lipoprotein cholesterol, very low density lipoprotein cholesterol, creatine kinase and lactate dehydrogenase were statistically increased in rats exposed to TAA. Administration of the studied extracts inhibited the hematobiochemical parameters and improved the physiological disturbances induced by TAA intoxication. Additionally, most improvements were noted in rats administrated with rosemary leaves extract followed by olive and rosemary leaves extracts and olive leaves extract. These results suggested that the effect of these extracts might be due to their antioxidant activities against TAA toxicity.

The role of structural C--H compared with phenolic OH sites on the antioxidant activity of oleuropein and its derivatives as a great non-flavonoid family of the olive components: a DFT study

Oleuropein and its derivatives are the main phenolic compounds of Olea europaea L. leaf and fruit. The structure-antioxidant activity relationship was considered for studying the radical scavenging activity of this non-flavonoid family of the olive components using density functional theory (DFT). The structure of these compounds were optimized employing the B3LYP/6-31G (d,p) and the role of some structural CH positions was compared with phenolic OH sites on radical scavenging. As a result, a radical unique position (C3) in the oleuropein, characterized by low BDE (Bond Dissociation Enthalpy), reasonable spin density and electron distribution, was identified. The experimental results of the previous publications of oleuropein for NO and OH scavenging confirmed the presence of this unique active site in its molecular structure. According to the results, 2,2-diphenylpicrylhydrazyl (DPPH) cannot find this non-marginal active site. Therefore, DPPH may not be a determinant assay for all antioxidant comparisons. Solvent effects were considered in all calculations using a Polarized Continuum Model (PCM) at the B3LYP/6-31G (d,p) level. Solvation calculations were carried out for benzene (ε=2.3) to simulate the oil environment compared to gas phase.

Effect of Extraction Conditions on the Antioxidant Activity of Olive Wood Extracts

An investigation to optimize the extraction yield and the radical scavenging activity from the agricultural by-product olive tree wood (Olea europaea L., cultivar Picual) using six different extraction protocols was carried out. Four olive wood samples from different geographical origin, and harvesting time have been used for comparison purposes. Among the fifty olive wood extracts obtained in this study, the most active ones were those prepared with ethyl acetate, either through direct extraction or by successive liquid-liquid partitioning procedures, the main components being the secoiridoids oleuropein and ligustroside. An acid hydrolysis pretreatment of olive wood samples before extractions did not improve the results. In the course of this study, two compounds were isolated from the ethanolic extracts of olive wood collected during the olives' harvesting season and identified as (7''R)-7''-ethoxyoleuropein (1) and (7''S)-7''-ethoxyoleuropein (2).

Dietary olive cake reduces the oxidation of lipids, including cholesterol, in lamb meat enriched in polyunsaturated fatty acids

Over 40 days, lambs were fed: concentrate (C), concentrate containing 20% linseed (L), concentrate containing 35% olive cake (OC), or concentrate containing 10% linseed and 17% olive cake (OCL). The polyunsaturated fatty acids (PUFA) and peroxidation index (PI) in phospholipids were increased by the L and OCL treatments (P=0.007 and P=0.003, respectively). The OC and OCL diets increased the concentration of tocopherol in muscle (P<0.001). Compared to the OC and OCL diet, the L diet increased fatty acid oxidation, measured as conjugated dienes (CD; P=0.003), peroxides (PV; P<0.001) and TBARS (P=0.002) in minced muscle over 11 days of storage in high-oxygen atmosphere. Also, the L diet increased (P<0.001) the levels cholesterol oxidation products (COPs). In conclusion, feeding olive cake improved the oxidative stability of lamb meat and the combination of olive cake and linseed improved the fatty acid composition of meat without compromising its oxidative stability.

Effect of dietary supplementation with olive pomaces on the performance and meat quality of growing rabbits

The aim was to investigate the effects of three types (A, B and C) of stoned and dehydrated olive pomaces (OPs), differing in olive cultivar, on productive performance and meat quality of growing rabbits. The inclusion of OPs (5%) negatively affected the performance of rabbits as it reduced the feed intake, growth rate, carcass weight and dressing out percentage (P<0.05). Compared with the control, the meat of OP rabbits had a greater amount of monounsaturated and a lower amount of polyunsaturated fatty acids (P<0.05), independent of the type of OP used. Oxidative processes in the meat of OPA and OPB were higher (P<0.05), whereas OPC showed the same levels as the control group. This was due to the higher total polyphenol concentration and to the concomitant lower peroxide value of OPC. These results recommend the use of OP in rabbit diet with caution, taking into account the quality of the by-product in terms of oxidative status.

Olive leaves (Olea europea L.) and α-tocopheryl acetate as feed antioxidants for improving the oxidative stability of α-linolenic acid-enriched eggs

Ninety-six brown Lohmann laying hens were equally assigned into four groups with six replicates. Hens within the control group were fed a corn-soybean-based diet supplemented with 4% linseed oil. Two other groups were given the same diet further supplemented with 5 or 10 g ground olive leaves/kg feed, while the diet of the fourth group was further supplemented with 200 mg α-tocopheryl acetate/kg. Supplementing diets with olive leaves had no effect on egg production, feed intake and egg traits. Eggs collected 28 days after feeding the experimental diets were analysed for lipid hydroperoxides and malondialdehyde (MDA) content, fatty acid profile, α-tocopherol concentrations and susceptibility to iron-induced lipid oxidation. Olive leaves were also analysed for total and individual phenolics, and total flavonoids, whereas their antioxidant capacity was determined using both the DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2-azinobis3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activity assays. Results showed that neither α-tocopheryl acetate nor olive leaves supplementation exerted (p>0.05) any effect on the fatty acid composition of n-3 eggs. Supplementing the diet with 5 g olive leaves/kg had no (p>0.05) effect on the hydroperoxide levels of n-3 eggs, while supplementing with 10 g olive leaves/kg or 200 mg α-tocopheryl acetate/kg, the lipid hydroperoxide levels were reduced (p≤0.05) compared to control. However, although hydroperoxides were reduced, MDA, a secondary lipid oxidation product, was not affected (p>0.05). Iron-induced lipid oxidation increased MDA values in eggs from all groups, the increase being higher (p≤0.05) in the control group and the group supplemented with 5 g olive leaves/kg. The group supplemented with 10 g olive leaves/kg presented MDA values lower (p≤0.05) than the control but higher (p≤0.05) than the α-tocopheryl acetate group, which presented MDA concentrations lower (p≤0.05) than all other experimental diets at all incubation time points.

Valuable nutrients and functional bioactives in different parts of olive (Olea europaea L.)-a review

The Olive tree (Olea europaea L.), a native of the Mediterranean basin and parts of Asia, is now widely cultivated in many other parts of the world for production of olive oil and table olives. Olive is a rich source of valuable nutrients and bioactives of medicinal and therapeutic interest. Olive fruit contains appreciable concentration, 1-3% of fresh pulp weight, of hydrophilic (phenolic acids, phenolic alchohols, flavonoids and secoiridoids) and lipophilic (cresols) phenolic compounds that are known to possess multiple biological activities such as antioxidant, anticarcinogenic, antiinflammatory, antimicrobial, antihypertensive, antidyslipidemic, cardiotonic, laxative, and antiplatelet. Other important compounds present in olive fruit are pectin, organic acids, and pigments. Virgin olive oil (VOO), extracted mechanically from the fruit, is also very popular for its nutritive and health-promoting potential, especially against cardiovascular disorders due to the presence of high levels of monounsaturates and other valuable minor components such as phenolics, phytosterols, tocopherols, carotenoids, chlorophyll and squalene. The cultivar, area of production, harvest time, and the processing techniques employed are some of the factors shown to influence the composition of olive fruit and olive oil. This review focuses comprehensively on the nutrients and high-value bioactives profile as well as medicinal and functional aspects of different parts of olives and its byproducts. Various factors affecting the composition of this food commodity of medicinal value are also discussed.

Radical scavenging-linked antioxidant activities of commonly used herbs and spices in Korea

Herbs and spices not only variety and racy flavour to Korean foods, they also are the richest source for antioxidant power. The present study evaluates the radical scavenging-linked antioxidant activities of hot water extracts from commonly used herbs and spices in Korea. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide anion scavenging activities of bay extract were 39.5% and 22.1%, respectively. The hydroxyl radical scavenging activity was in order of dill (50.0%) > bay (31.3%) > garlic (27.9%) > white pepper and black pepper (15.1-15.3%) > onion (10.1%) extracts. Bay extract had the highest total phenolic content (17.86 μg CE/g). High correlation coefficients were found between the total phenol content and DPPH radical scavenging activity (R = 0.9162). These results indicate that herbs and spices had high antioxidant activity that is partly due to the phenolic compounds and provide basic data for further development of processed food products.

Antioxidant activities of hot water extracts from various spices

Recently, the natural spices and herbs such as rosemary, oregano, and caraway have been used for the processing of meat products. This study investigates the antioxidant activity of 13 spices commonly used in meat processing plants. The hot water extracts were then used for evaluation of total phenolic content, total flavonoids content and antioxidant activities. Our results show that the hot water extract of oregano gave the highest extraction yield (41.33%) whereas mace (7.64%) gave the lowest. The DPPH radical scavenging ability of the spice extracts can be ranked against ascorbic acid in the order ascorbic acid > clove > thyme > rosemary > savory > oregano. The values for superoxide anion radical scavenging activities were in the order of marjoram > rosemary > oregano > cumin > savory > basil > thyme > fennel > coriander > ascorbic acid. When compared to ascorbic acid (48.72%), the hydroxyl radical scavenging activities of turmeric and mace were found to be higher (p < 0.001). Clove had the highest total phenolic content (108.28 μg catechin equivalent (CE)/g). The total flavonoid content of the spices varied from 324.08 μg quercetin equivalent (QE)/g for thyme to 3.38 μg QE/g for coriander. Our results indicate that hot water extract of several spices had a high antioxidant activity which is partly due to the phenolic and flavonoid compounds. This provides basic data, having implications for further development of processed food products.

Assessment of phenolics-enriched extract and fractions of olive leaves and their antioxidant activities

Recent studies suggest that olive leaf is a significant source of bioactive phenolic compounds comparable to olive oil and fruits. Identifying appropriate extraction methods is thus an important step to increase the yield of such bioactive components from olive leaf, which is otherwise agricultural waste. The present study evaluates phenolic contents and compositions of olive leaf extracted by several solvent methods and to further establish their antioxidant activities using various radical scavenging systems. Total flavonoid and phenolic contents were significantly higher in the 80% ethanol extract, butanol, and ethylacetate fractions than hexane, chloroform and water fractions (p<0.05). Oleuropein was identified as a major phenolic compound with considerable contents in these major three fractions and the extract that correlated with their higher antioxidant and radical scavenging. These results indicate that olive leaf contains significant amounts of oleuropein and phenolics, important factors for antioxidant capacity, which can be substantially modified by different extraction methods.

Efficacy of oleuropein against UVB irradiation: preliminary evaluation

Oleuropein, a phenolic compound derived from olive leaves and oil, is known to possess several biological properties, many of which may be attributed to its antioxidant and free radical-scavenging activities. Nevertheless, up to now, the cosmetic activity of this molecule has not been extensively investigated. The aim of this work was to evaluate the cosmetic properties of oleuropein against UVB-induced erythema. To this end, an emulsion and an emulgel containing oleuropein were prepared, applied and evaluated on healthy volunteers who had undergone UVB irradiation to investigate its protective and/or lenitive activity. Protective effect was assayed by application of topical preparations before irradiation and lenitive effect was evaluated after erythema induction. Vitamin E was used as the reference compound. Our study was carried out by using noninvasive techniques to assess specific skin parameters: barrier function, skin colour and microcirculation. Results clearly showed that oleuropein formulations highlighted lenitive efficacy by reducing erythema, transepidermal water loss and blood flow of about 22%, 35% and 30% respectively. The study allowed us to point out the lenitive property of oleuropein, opening the way to further trials to deepen our specific knowledge about this natural molecule, which could be used in association with other active ingredients in cosmetics to repair UV damages.

The effects of polyphenols in olive leaves on platelet function

INTRODUCTION

The phenolic compounds of olive leaves and olive oils in the Mediterranean diet have been associated with a reduced incidence of heart disease. Accordingly, antioxidant-rich diets may prevent the deleterious effects of oxidative metabolism by scavenging free radicals, thus inhibiting oxidation and delaying atherosclerosis. The process involves phospholipase C activation and arachidonic acid metabolism, and is thought to reduce hydrogen peroxide (H(2)O(2)). In our study, an extract of Olea europaea L. leaves was used. The active phenolic compounds in this extract are part of the secoiridoid family, known for their capacity to scavenge H(2)O(2). The results from this study will help to improve our understanding of effects of polyphenol antioxidants in olive leaf extract on platelet function.

METHODS

Full blood examination (FBE), platelet aggregation, and ATP release were performed on samples from fasting, normal, healthy male subjects. Platelet function at increasing concentrations of oleuropein was investigated through measures of platelet aggregation and ATP release from activated platelets.

RESULTS

Blood analysis (n=11) revealed a significant dose-dependant reduction in platelet activity with olive extract concentrations of 1.0% v/v (P<0.001). ATP Release showed a similar pattern (P=0.02).

CONCLUSIONS

Olive leaf polyphenols derived from O. europaea L. leaves inhibited in vitro platelet activation in healthy, non-smoking males. Further bioavailability studies need to be undertaken to determine the in vivo effect of extract on platelet function and to validate the present results.

Bioscreening of Australian olive mill waste extracts: Biophenol content, antioxidant, antimicrobial and molluscicidal activities

The biophenolic fraction was characterized in olive mill waste (OMW) obtained as a by-product from processing of Mission and Frantoio olive fruit. OMW produced from the Mission fruit contained higher total phenol content. Individual biophenols with the exception of verbascoside and a hydroxytyrosol-secoiridoid were also present at higher concentrations in the OMW produced from Mission cultivar. Antioxidant activities were measured in aqueous (DPPH) and emulsion (BCBT) systems. The Frantoio extract was more active than the Mission extract in the DPPH assay - EC(50) values were 28.3+/-1.7 ppm and 34.7+/-1.7 ppm, respectively. Activities were reversed in the BCBT, with the Mission extract (EC(50) 60.6+/-2.3 ppm) more potent than the Frantoio extract (EC(50) 79.9+/-2.0 ppm), and this may be related to the more lipophilic nature of the Mission extract. Both extracts showed broad spectrum antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa; whereas individual biophenols (hydroxytyrosol, luteolin, oleuropein) showed more limited activity. Molluscicidal activity was measured against Isidorella newcombi and LD(50) values were 424 ppm and 541 ppm for Mission and Frantoio extracts, respectively. The results suggest that OMW may be utilised as a source of bioactive compounds.