Research ArticleReceived: 5 December 2013 Revised: 15 January 2014 Accepted article published: 10 March 2014 Published online in Wiley Online Library:

(wileyonlinelibrary.com) DOI 10.1002/jsfa.6638

Effect of lycopene-enriched olive and argan oilsupon lipid serum parameters inWistar ratsAziouz Aidoud,a Ali Ammouche,b María Garridoc* and Ana B Rodriguezc

Abstract

BACKGROUND: Lycopenehas thehighest antioxidant activitywithin carotenoidsand is aneffective free radical scavenger.Virginolive oil (VOO) and argan oil (AO) contain trace amounts of a wide variety of phytochemicals which have desirable nutritionalproperties. The present study intended to assess the effect of various dietary VOO and AO in combination with lycopeneconsumption on serum biochemical parameters, including total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C),high-density lipoprotein-cholesterol (HDL-C), triglycerides (TGs) and phospholipids, as well as on hepatosomatic index (HSI)of rats.

RESULTS: Results showed that ingestion of VOO and AO diminished TC, LDL-C, TGs and phospholipid levels, whereas the HDL-Clevels augmented in all the groups assayed. The enrichment of VOO and AO with lycopene improved the beneficial effectsderived from the consumption of both oils on serum biochemical parameters. A decrease in body weight gain and HSI wasdetected after the consumption of lycopene-enriched oils.

CONCLUSION: These findings suggest that the inclusionof lycopene inVOOandAOmaybeused as a natural tool to fight againsthyperlipidaemic and hypercholesterolaemic-derived disorders.© 2014 Society of Chemical Industry

Keywords: lycopene; virgin olive oil; argan oil; low-density lipoprotein-cholesterol; high-density lipoprotein-cholesterol; triglyceride

INTRODUCTIONThemost common dietary antioxidant supplementations are vita-mins A, C, and E, including �-carotene, which are given throughartificial (tablets) or natural (fruits or vegetables)matrices. Actually,the development of antioxidant-enriched foodstuffs is revolution-ising the nutritional field since the synergic effects of phytochem-icals present in foodstuffs have reported more beneficial effectsthan the supplementation with an isolated, specific antioxidant.1,2

In fact, current dietary guidelines recommend the consump-tion of fruits and vegetables since they are a natural source ofphytochemicals.Scientific evidence supports the idea that there may be as

many as 10 000 different phytochemicals with potential biologicalactivities. Carotenoids have received considerable attention dueto their antioxidant properties.3 Quantitatively, the most impor-tant carotenoids in human diet are �-carotene, lycopene, lutein,�-cryptoxanthin, and astaxanthin. Lycopene is the most preva-lent carotenoid in the Mediterranean diet, being abundant inred fruits such as tomato, processed tomato products and otherfruits, including watermelon, papaya, guava, pink grapefruit andapricot.4 This red pigment has the highest antioxidant activitywithin carotenoids and is an effective free radical scavenger.5

Numerous epidemiological studies have suggested that the intakeof lycopene-containing foods aswell as blood lycopene concentra-tions are inversely related to incidence of cardiovascular diseaseand prostate cancer.6,7 Moreover, lycopene has been proposedto prevent carcinogenesis and atherogenesis by protecting criti-cal biomolecules including lipids, low-density lipoproteins (LDL),

proteins, and DNA.8,9 It is important to note that the absorptionof this carotenoid from food is dependent on several factors suchas the type of dietary fat. In this sense, Lee et al. have reportedthat the consumption of tomato products with olive oil signifi-cantly raises the plasma antioxidant capacity whereas no effectwas observed when the sunflower oil was used.10 Similarly, theintake of lycopene-rich foods cooked with monounsaturated fathas been suggested tohave addedbenefits against coronary heartdisease.11

Importantly, monounsaturated and polyunsaturated fatty acids(MUFA and PUFA, respectively), when consumed in place of sat-urated fatty acids, are capable of reducing plasma cholesterol.12

Besides, triglycerides (TGs) may have cholesterol-lowering effectsas well.13 Virgin olive oil (VOO), the main source of dietary fat inthe Mediterranean diet, contains high levels of MUFA, polypheno-lic compounds, squalene and �-tocopherol, which are antioxidant

∗ Correspondence to: María Garrido, Department of Physiology, Faculty of Sci-ence, University of Extremadura, Avda. Elvas s/n 06006 Badajoz, Spain. E-mail:mgaalvarez@unex.es

a Department of Biology, Faculty of Life and Nature Sciences, Ziane AchourUniversity, Djelfa, Algeria

b Department of Food Technology and Human Nutrition, National High Collegeof Agronomy El-Harrach, 16111, Algeria

c Department of Physiology (Neuroimmunophysiology and ChrononutritionResearch Group), Faculty of Science, University of Extremadura, 06006, Bada-joz, Spain

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molecules that have been found to inhibit oxidative stress.14 Pre-vious studies in humans have demonstrated that olive oil, com-pared with seed oil, has the ability to prevent lipid peroxidationdue to its high MUFA content.15 In fact, olive oil-enriched dietshave shown to be more effective in lowering total cholesterol(TC) and low-density lipoprotein-cholesterol (LDL-C) than conven-tional dietary treatments thatdonot containhigh levels ofMUFA.16

Arganoil (AO) presents high levels of bioactive compounds, partic-ularly polyunsaturatedandmonounsaturated fatty acids, polyphe-nols, tocopherols, sterols and �-carotene, which are well known aspowerful antioxidants.17 Based on its composition, crude argan oilhas been shown to be effective in reducing plasma cholesterol andLDL-C levels in rat fed with hypercholesterolaemic diet.18 Similarlyto VOO, AO contains a variety of antioxidant molecules such asplant sterols, polyphenols and tocopherols, which may also havebeneficial effects against inflammatory disorders.19 Finally, Ben-zaria et al. have shown that the effects of AO on immune cells arevery similar to those of VOO, suggesting that AO may be usedas a balanced dietary supply without marked adverse effects onimmune cell function.20

The present study intended to assess the effect of various dietaryVOOsandAOs in combinationwith tomato lycopene consumptionon serum biochemical parameters, including TC, high-densitylipoprotein-cholesterol (HDL-C), LDL-C, TGs and phospholipids, aswell as on hepatosomatic index (HIS) of male Wistar–Albino rats.

METHODSAnimalsSeventy-five male Wistar rats (Rattus norvegicus) at their weaningage (3–4weeks) and weighed 87. 98± 15.95 g (n= 15 per group)were obtained from Animal Laboratory (Institute Pasteur, Algiers,Algeria). Animals were allowed 1week of in-house acclimatisation.They were individually housed under controlled environmentalconditions (20 ∘C; 50% humidity), maintained under a 12/12 hlight/dark cycle and fed ad libitum (food and water) during 9weeks. All experiments were carried out according to a procedureapproved by local ethics committees (Ref. no. PDT 08A008), inaccordance with the current guidelines for the care of laboratoryanimals, and in accordance with the National Institutes of HealthGuide (Reg. No. 488/160/1999/CPCSEA).

Animal treatmentsRats were divided in five experimental groups and fed a dif-ferent experimental diet each during 9 weeks: control group(C), virgin olive oil group (VOO), lycopene-enriched virgin oliveoil (VOO+ Lyc), argan oil group (AO), and lycopene-enrichedargan oil (AO+ Lyc). Control animals consumed standard food andwater, whereas treatment groups received a standard food supple-mented with: 10% of virgin olive oil (VOO); 10% of virgin olive oilrich plus 0.1% of lycopene (VOO+ Lyc); 10% of argan oil (AO); and10%of arganoil plus 0.1%of lycopene (AO+ Lyc), respectively. TheVOO and AO were purchased from the local market in Algeria andlycopenewas acquired fromDSM Inc. (Istambul, Turkey). The com-position of the different diets (Table 1) was prepared following therecommendations of Hochgraf et al.,21 Sánchez-Muniz et al.22 andVarela and Ruiz-Roso.23 Briefly, the composition of the diet was asfollows (g 100 g−1 of food): protein, 16; sucrose, 28; fat, 10; miner-als, 7; fibre (agar), 3; and complete up to 100 g with corn starch.The quantity of skimmedmilk powder used per diet (42.11 g) pro-vided 16 g protein, 20.63 g sucrose and 3.16 g minerals. The diets

Table 1. Compositions of the diets (g 100 g−1 of food) for thedifferent rat groups

Ingredient Control VOO VOO+ Lyc AO AO+ Lyc

Skimmedmilk powder 42.11 42.11 42.11 42.11 42.11

Sucrose 7.37 7.37 7.37 7.37 7.37

Sunflower oil 10 – – – –

Virgin olive oil – 10 10 – –

Argan oil – – – 10 10

Lycopene – – 0.1 – 0.1

Mineral supplement 3.84 3.84 3.84 3.84 3.84

Vitamin supplement 1 1 1 1 1

Fibre (agar) 3 3 3 3 3

DL-Methionine 0.3 0.3 0.3 0.3 0.3

Humidity 9 9 9 9 9

Corn starch 23.38 23.28 23.38 23.38 23.28

Total 100 100 100 100 100

Energy (Kcal) 359 359 359 359 359

Control, laboratory standard food diet; VOO, virgin olive oil diet;VOO+ Lyc, lycopene-enriched virgin olive oil diet; AO, argan oil diet;AO+ Lyc, lycopene-enriched argan oil diet.

wereprepared in the laboratory in 500-g amounts every 3days andstored at 4 ∘C in hermetic boxes. Everymorning, fresh portions suf-ficient for a 1-day supply were fed to the animals.

Blood sampling collectionBlood samples were drawn by cutting the tail of all rats before thebeginning of the assay (basal conditions), as well as after 3 and6 weeks of administration of the different dietary treatments. Atthe end of the 9 weeks of experimental treatment, the animalswere deprived of food overnight, and then anaesthetised byintramuscular injection of 50mg kg−1 ketamine and sacrificed toobtain blood samples by puncturing the heart ventricle. Bloodsamples (2mL)were placed in dry clean centrifuge tubes, and thencentrifuged for 10min at 900× g. Serum was carefully separatedinto clean dry tubes by using a Pasteur pipette and kept frozen at−30 ∘C until analysis.

Biochemical determinations of serum lipid parametersTC, HDL-C, and TGs were determined by enzymatic kits fromAbcam (Cambridge, MA, USA) on a Cobas Analyzer (Roche Diag-nostics, Paris, France). Levels of LDL-C were calculated using theFriedewald formula (LDL-C= TC−HDL-C− TGs/5).24 Serum phos-pholipids were determined by an enzymatic colorimetric method(Bio-Direct, Taunton, MA, USA).

Tissue preparation andmeasurement of hepatosomatic indexAfter sacrifying the rats, the liver was separated from each animal,washed with ice-cold physiological saline and weighed to calcu-late HSI. The HSI was calculated by comparing the liver weight tothe body weight (organ weight/total body weight× 100).

Physico-chemical characterisation and fatty acids profileof the experimental oilsThe refractive index of the oils wasmeasured at room temperatureusing an Abbé refractometer (Carl Zeiss, Jena, Germany). The

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Table 2. Fatty acids composition of the oils assayed

Type of fatty acids Isomer % VOO % AO

SFA 14:0 0.10 0.17

15:0 0.00 0.00

16:0 10.80 13.73

18:0 3.50 6.07

20:0 0.20 0.00

Total – 14.6 19.97

MUFA 16:1 0.40 0.14

18:1 73.40 47.43

20:1 0.20 0.00

Total – 74 47.57

PUFA 18:2n-6 11.10 32.46

18:3n-6 0.30 0.00

Total – 11.40 32.46

Total UFA – 85.40 80.03

SFA/UFA – 0.17 0.25

SFA, saturated fatty acid; MUFA, monounsaturated fatty acid; PUFA,polyunsaturated fatty acid; UFA, unsaturated fatty acid; SFA/UFA, sat-urated to unsaturated fatty acids ratio; VOO, virgin olive oil; AO,argan oil.

chemical parameters (iodine, peroxide, saponification and acidvalues) were determined using standardmethods.25 The fatty acidmethyl esters of olive oil and argan oil were analysed by gaschromatography (GC) with Chrompack CP 900226 and results aregiven in Table 2.

Determination of minor compounds of the experimental oilsThe analysis of the individual sterols compounds was achieved bymeans of a HP Agilent 6890 gas chromatograph equipped with aflame ionisation detector (FID) following themethod proposed bythe IOC.27 Phenolic compounds were chromatographically sepa-rated by means of a 1200 Agilent HPLC instrument equipped withUV and fluorescence spectrometer detector (Agilent technologies,Waldbronn, Germany). Compounds separation was achieved at20 ∘ C in a C18 chromatographic column (Aces 250mm× 4.6mm).Identification and quantification of the compounds was achievedby means of both detection systems [280, 320, 360 and 520 nmfor the UV detector and 280 (excitation wavelength) and 320 nm(emission wavelength) for the fluorescence detector]. Determina-tion of the concentration of tocopherols was in accordance withIUPAC method 243228 by using a 1200 Agilent HPLC instrumentequipped with UV and fluorescence spectrometer detector. Sep-aration of the compounds was achieved in a Spherisorb SS NH2column (250mm× 64mm× 5mm), and their identification andquantification was achieved by using the UV spectrometer detec-tor set at 295 nm.

Statistical analysisData were expressed as mean± SD of the number of determi-nations carried out in duplicate, unless otherwise indicated. Tocompare the different treatments, statistical significance was cal-culated by one-way analysis of variance (ANOVA) followed by theTukey post-hoc test. The degree of significance was set at P< 0.05.All analyses were performed using GraphPad Prism (version 5.0,2007; GraphPad Software Inc., San Diego, CA, USA).

Table 3. Phytochemical composition of argan oil and virgin olive oil

Compound Argan oil Virgin olive oil

Tocopherols (mg kg−1 oil)�-Tocopherol 476± 3 25± 3�-Tocopherol 38± 2 184± 2�-Tocopherol 113± 5 44± 1Total 627± 13 253± 4Sterols (mg 100 g−1 oil)Schottenol 132± 15 –Spinasterol 118± 4 –�8–22 Stigmastadiene-3�-ol 11± 1 –�-Sitosterol – 154± 4Campesterol 2 5± 2Stigmasterol – –Other 34± 2 123± 8Total 297± 14 283± 14Phenolic compounds (mg kg−1 oil)Vanillic acid 0.067± 3 0.343± 9Syringic acid 0.037± 5 0Ferulic acid 3.147± 20 0.054± 1Tyrosol 0.012± 1 19.617± 18Other 0 772.400± 43Total 3.263± 29 792.414± 77

Each value represents the mean± SD from three replicates.

RESULTSIn relation to phytochemical composition of experimental oils(Table 3), the results showed that AO possesses higher totaltocopherols (627± 13mg kg−1 AO) and sterols concentration(297± 14mg 100 g−1 AO) than VOO (253± 4 and 283± 14mg100 g−1 VOO, respectively). However, VOO presents a higherphenolic concentration than AO (792.414± 77mg kg−1 VOO vs.3.263± 29mg kg−1 AO).Figure 1A shows thebodyweight of eachgroupof ratsmeasured

at four different time points. There were no significant differencesin the body weight evolution between the different treatments(Fig. 1B). However, it was observed that the body weight gain ofVOO+ Lyc groupwas significantly (P< 0.05) lower than in the con-trol group. Moreover, a slight tendency to decrease was obtainedin the bodyweight gain of AO+ Lyc groupwith respect to the con-trol group. No significant differences were detected for the othergroups. Concomitant with the findings present in Fig. 1B, the HSIwas significantly decreased (P< 0.05) in both the VOO+ Lyc andAO+ Lyc groups with respect to the control group (Fig. 1C).Figure 2 shows cholesterol concentrations representedbyTC lev-

els (Fig. 2A), LDL-C (Fig. 2B) and HDL-C concentrations (Fig. 2C). TClevels in VOO group were significantly (P< 0.05) reduced at weeks6 and 9 with respect to the control group. Regarding VOO+ Lycgroup, TC levels were diminished (P< 0.05) since week 3. From thispoint on, this parameter was gradually further reduced in weeks6 and 9 (P< 0.05) compared to the control group. Related to AO,better results were obtained in the group AO+ Lyc, since totalcholesterol levels were reduced (P< 0.05) after 6 and 9 weeksof treatment, whereas in AO group, cholesterol levels were sta-tistically (P< 0.05) decreased only after 9 weeks of treatmentcompared to the control group. As for LDL-C concentrations, itprogressively decreased (P< 0.05) throughout the study in bothVOO-treated and VOO+ Lyc-treated groups with respect to the

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Figure 1. Effect of lycopene supplementation on body weight and hepatosomatic index. (A) Weekly record of body weight of control rats and rats fed adiet supplemented with virgin olive oil (VOO), lycopene-enriched virgin olive oil (VOO+Lyc), argan oil (AO) or lycopene-enriched argan oil (AO+Lyc). (B)Body weight gain at the end of the study (after 9 weeks of treatment) in control, VOO, VOO+Lyc, AO and AO+Lyc groups. (C) Hepatosomatic index (HIS)at the end of the study (after 9 weeks of treatment) in control, VOO, VOO+Lyc, AO and AO+Lyc groups. Values represent mean ± SD of 15 animals. *P <

0.05 with respect to the control group.

control group. It is noteworthy the striking diminution in LDL-Clevels after 9 weeks of treatment with VOO+ Lyc which had thegreatest hypocholesterolaemic effect, thereby diminishing LDL-Cconcentration by 94%. Concerning AO groups, the LDL-C concen-trations gradually diminished (P< 0.05) in AO+ Lyc group alongthe study, the least valuebeing reached after 9weeks of treatment.Similarly, levels of LDL-C were significantly decreased (P< 0.05) inAO group, but only after 9 weeks of treatment.In Fig. 2C, as in previous figures, better findings were achieved in

groups treated with lycopene-enriched oils than in groups treatedwith oil alone. Thus, in VOO+ Lyc, HDL-C concentration increased(P< 0.05) after 3, 6 and 9 weeks of treatment with respect to thecontrol group, while HDL-C levels started to significantly raised

after 6 and 9 weeks of treatment with VOO in relation to thecontrol group. The ingestion of AO+ Lyc elevated (P< 0.05) HDL-Cconcentration after 6 and 9 weeks of treatment in relation to thecontrol group. On the contrary, in AO group, the levels of HDL-Cwere only significantly (P< 0.05) waned at the end of the study(week 9).TG concentrations (Fig. 3A)werediminished (P< 0.05) after 6 and

9 weeks of treatment with VOO with respect to the control group.Simultaneously, when VOO was supplemented with lycopene(VOO+ Lyc) the reduction (P< 0.05) in TG levels appeared after 3weeks of treatment andwas evenmore evident after 6 and9weeksof supplementation. On the other hand, the consumption of AOand AO+ Lyc substantially reduced (P< 0.05) the concentration of

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Figure2. Effect of lycopene supplementation on cholesterol levels. (A) Total cholesterol levels obtained after 3, 6 and 9weeks of treatmentwith virgin oliveoil (VOO), lycopene-enriched virgin olive oil (VOO+Lyc), argan oil (AO) or lycopene-enriched argan oil (AO+Lyc). (B) Low density lipoprotein-cholesterol(LDL-C) levels reached after 3, 6 and 9 weeks of treatment with VOO, VOO+Lyc, AO or AO+Lyc. (C) High density lipoprotein-cholesterol (HDL-C) foundafter 3, 6 and 9 weeks of treatment with VOO, VOO+Lyc, AO or AO+Lyc. Values represent mean ± SD of 15 animals. *P < 0.05 with respect to the controlgroup.

TGs after 6 and 9 weeks of treatment with respect to the controlgroup.Regarding phospholipid levels (Fig. 3B), the consumption of

lycopene-enriched oils, i.e. VOO+ Lyc and AO+ Lyc, caused a sub-stantial decline (P< 0.05) in phospholipids levels after 3 weeks oftreatment that was further reduced after 6 and 9 weeks (P< 0.05).However, the consumption of VOO and AO without being supple-mentedwith lycopene decreased (P< 0.05) the phospholipids lev-els only after 6 and 9 weeks of treatment. Taken together, all thesefindings pointed out that lycopene supplementation enhancedthe positive effects exerted by the consumption of both virginolive oil and argan oil on lipid serum parameters.

DISCUSSIONBoth epidemiological studies and dietary intervention trials havecorrelated adherence to a Mediterranean dietary pattern and pos-itive effects on health. Beneficial effects provided by a Mediter-ranean diet are due to synergistic interactions of phytochemicalspresent in foodstuffs rather than the effect of isolated bioactivecompounds.2

In this study, we found that the enrichment of VOO and AOwithlycopene enhanced the beneficial effects derived from the inges-tion of both oils. Thus, body weight gain was noticeably lower inVOO+ Lyc group and slightly lower in AO+ Lyc groupwith respectto the control group. At this respect, Kim et al. also found that a

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Figure 3. Effect of lycopene supplementation on lipid serum parameters. (A) Tryglicerides concentration obtained after 3, 6 and 9 weeks of treatmentwith virgin olive oil (VOO), lycopene-enriched virgin olive oil (VOO+Lyc), argan oil (AO) or lycopene-enriched argan oil (AO+Lyc). (B) Phospolipids levelsreached after 3, 6 and 9 weeks of treatment with VOO, VOO+Lyc, AO or AO+Lyc. Values represent mean ± SD of 15 animals. *P < 0.05 with respect to thecontrol.

lycopene-enriched diet suppressed body weight gain, which maybe owing to alterations in lipid metabolic enzyme activity in liverand adipose tissue.29 However, other studies have reported noeffect of lycopene supplementation on body weight.30,31 Despitethe fact that clinical trials determining the effect of lycopene intakeon body weight are currently lacking, a recent small-scale clini-cal trial reported that lycopene did not improve weight loss inobese humans. These findings may be explained by several fac-tors, including the intervention duration, dietary intake, lycopenedosing or the small sample size.32

The HSI is usually used to assess changes in gross liver weightwith respect to the overall bodyweight.33 HSI is sensitive to a widevariety of stressors such as nutritional, e.g. using oxidised fryingoil, and chemical stressors.34,35 At this respect, increases in the HSIare normally associated with enhanced detoxification activities inresponse to the presence of toxic compounds.36,37 On the contrary,antioxidants presumably possess protective actions on this index,which decreases upon exposure to antioxidants, as previouslyreported.35 Importantly, we found that the supplementation withlycopene reduced the HSI in rats fed a normal diet, whereas thesupplementation with VOO or AO alone did not affect such anindex.Hypercholesterolaemia is one of the most important risk fac-

tors for atherosclerosis. In fact, elevated levels of TC and LDL-Chave been established as risk factors for atherosclerosis, which

is the primary cause of cardiovascular disease (CVD).38 On thecontrary, elevated HDL-C levels possess protective,anti-inflammatory properties.39 Our results showed that theingestion of VOO and AO diminished total cholesterol and LDL-Clevels of rats, whereas HDL-C concentration augmented. At thesame time, these oils ameliorated lipid serum parameters, namelyTG and phospolipids. Phytosterols and phenolics possess direct orindirect hypocholesterolaemic activity.40,41 Thus, phenolic com-pounds present in olive oil have been shown to protect LDL fromlipid peroxidation in both in vitro42 and in vivo43 studies. In theEUROLIVE study, a clinical trial, the benefits of high-polyphenololive oil consumption at real-life olive oil doses were directlyassociated with a decrease of markers LDL oxidation.44 Addi-tionally, it has been demonstrated that sterols are bile acidsequestrants and acyl-coenzyme A cholesterol acyltransferaseactivity inhibitors and its consumption leads to lower levels ofplasma LDL-C.45 Likewise, studies in rats have found that theintake of phenol rich VOO decreases TC, LDL-C and TG levels,46

and substantially increases HDL-C concentrations.47 Moreover,it has been reported that MUFA and PUFA are also capable ofreducing plasma cholesterol.12 Consequently, we could assumethat the antioxidant compounds present in VOO contributed toameliorating cholesterol metabolism. Moreover, polyphenols andtocopherols present in VOOhave proven to exert beneficial effectson health such as reduction of CVD risk,48 immunomodulatory

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effects as well as the ability to partially reverse some inflammatoryconditions.49,50 Likewise, although the quantities of �-tocopherol(vitamin E) and carotenoids present in a daily consumption ofVOO are low, its chronic ingestion contributes to the overall poolof antioxidants in the human body.51

Related to argan oil, Berrougui et al. have demonstrated thehypolipidaemic and hypocholesterolaemic effect of this oil inrats.18 Minor compounds of AO, such as plant sterols, may beimplicated in the hypocholesterolaemic effect of AO.52 Indeed, themolecular structure of those plant sterols is very similar to that ofhuman cholesterol, and thus plant sterols intake reduce choles-terol absorption by competing with endogenous cholesterol.53

Additionally, several clinical trials have also demonstrated thebenefits of argan oil on lipid serum profile and oxidation.17 Forexample, Berrougui et al. showed that the phenolic fraction ofargan oil prevents LDL-C oxidation in isolated human plasma andenhances reverse cholesterol transport by HDL levels.54

All these findings are in accordance with those reported in ourstudy. The protective effects of AO are probably due to its highcontents of powerful antioxidants, particularly polyphenols, toco-pherols and sterols.55 Hence, antioxidants present in argan oil arebelieved to prevent or delay the onset of reactive oxygen speciesafter lipid peroxidation observed in rats or human plasma.18,54

Moreover, its polyphenols, tocopherols and sterols have demon-strated to possess anti-atherosclerotic activity,56 highlighting thepotential biological properties of AO.It is important to note that in the current study the benefi-

cal effects reported by the consumption of VOO and AO werefurther improved by the enrichment of both oils with lycopene.Lycopene supplementation enhanced cholesterol and serum lipidparameters not only quantitatively, but also temporarily as theeffects appeared much earlier. Numerous studies have reportedthe potential anti-atherogenic role of lycopene.57 Thus, Vergheseet al. observed that the supplementationwith lycopene decreaseddiet-induced serum TC and LDL-C levels and increased HDL-C inrabbits.58 Likewise, Lorenz et al., in the same animal model, provedthat the animal group treated with lycopene beadlets was asso-ciated with a significant reduction by about 50% in TC and LDL-Clevelswith respect tohigh-cholesterol andplacebogroups.59 Addi-tionally, Melendez-Martinez et al. found that supplementationwith tomato extract, which contains mainly lycopene, decreaseshepatic inflammation and plasma TC associated with high dietaryfat intake.60 Apart from these animal studies, there are a numberof ex vivo studies that demonstrate delayed chemically inducedLDL oxidation lag time from blood obtained from human subjectsfed tomatoproducts, tomato extracts, and lycopeneoleoresin cap-sules as sources of lycopene.61,62 In this respect, the inclusion oflycopene into the diet may contribute to prevent or amelioratehyperlipidemic and hypercholesterolaemic-derived disorders.

CONCLUSIONTaking everything into account, the inclusion of lycopene in aVOO and AO enhances the hypolipidaemic and hypocholestero-laemic effects produced by the ingestion of both oils. These bio-logical properties may have a significant impact on the well-beingof a population, particularly in obesity, which is associated withelevated TG levels, decreased in HDL-cholesterol and high LDLoxidation. In addition, obesity is commonly linked with patholo-gies including dyslipidaemia, glucose intolerance, insulin resis-tance anddiabetesmellitus, all ofwhich are risk factors for CVDandmortality.

ACKNOWLEDGEMENTSThis work was supported by Gobierno de Extremadura (Re:GRU10003). We thank the team at the animal laboratory of PasteurInstitute (Algiers, Algeria), and the Biochemistry Laboratory of theMilitary Hospital (Algiers, Algeria) for their help.

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