Journal of Food Composition and Analysis 31 (2013) 20–23

Short communication

New seed oils of Boraginaceae rich in stearidonic and gamma-linolenic acidsfrom the Maghreb region

Jose Luis Guil-Guerrero a,*, Miguel Angel Rincon-Cervera a, Francisco Gomez-Mercado b,Rebeca Pilar Ramos-Bueno a, Elena Venegas-Venegas a

a Tecnologıa de Alimentos, Universidad de Almerıa, 04120 Almerıa, Spainb Biologıa Vegetal y Ecologıa, Universidad de Almerıa, 04120 Almerıa, Spain

A R T I C L E I N F O

Article history:

Received 20 February 2012

Received in revised form 27 October 2012

Accepted 5 February 2013

Keywords:

Food analysis

Food composition

PUFAs

Stearidonic acid

g-Linolenic acid

Oilseeds

Borago officinalis

Echium plantagineum

Echium parviflorum

Echium sericeum

A B S T R A C T

The main goal of this work was to find new seed oils rich in g-linolenic acid (GLA, 18:3n-6) and

stearidonic acid (SDA, 18:4n-3) as alternatives to the commercially available oils, such as those from fish

and borage. To this end, seeds of selected Boraginaceae species growing wild in the North Africa region

(Maghreb) were collected and analyzed. The key finding is that two Echium species have been identified

as new sources of valuables fatty acids (FAs): Echium sericeum and Echium parviflorum, showing 18.3%

GLA and 17.3% SDA on total FAs respectively. Both of them could be cultivated to provide functional oils,

polyunsaturated FA (PUFA) concentrates or pure FAs, among other uses. It is also noteworthy that the

seed oils of Borago officinalis and Echium plantagineum gathered in different locations showed different

GLA and SDA percentages, respectively.

� 2013 Elsevier Inc. All rights reserved.

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Journal of Food Composition and Analysis

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1. Introduction

Nowadays, the health effects of fish oil consumption are wellestablished on the basis of extensive experimental and epidemio-logical studies. The health benefits linked to its intake areattributed to the high amount of n-3 PUFA that are containedtherein, mainly eicosapentaenoic (EPA, 20:5n-3) and docosahex-aenoic (DHA, 22:6n-3) acids (Das, 2006). However, fish oil cancontain high levels of contaminants such as polychlorinatedbiphenyls (PCBs), dioxins and methylmercury; therefore its intakemay constitute a potential cardiovascular and neurological risk(Ruzzin and Jacobs, 2012). In addition, by considering the over-exploitation of fisheries resources, fish oil availability in theimmediate future is questionable (Guil-Guerrero et al., 2011).

The commonly consumed seed oils may provide only veryrestricted daily amounts of PUFAs body needs, because they

Abbreviations: AA, arachidonic acid; ALA, a-linolenic acid; DHA, docosahexaenoic

acid; GLA, g-linolenic acid; LA, linoleic acid; PUFAs, polyunsaturated fatty acids;

SDA, stearidonic acid.

* Corresponding author. Tel.: +34 950 015586; fax: +34 950 015484.

E-mail address: jlguil@ual.es (J.L. Guil-Guerrero).

0889-1575/$ – see front matter � 2013 Elsevier Inc. All rights reserved.

http://dx.doi.org/10.1016/j.jfca.2013.02.007

contain mainly those that belong to the C18 series, namely linoleic(LA, 18:2n-6) and a-linolenic (ALA, 18:3n-3) acids, which aremetabolized to GLA and arachidonic acid (AA, 20:4n-6) (n-6pathway) and to SDA, EPA and DHA (n-3 pathway) respectively.The first step for both pathways, in which ALA is metabolized toSDA and LA to GLA by the enzyme D6-desaturase is rate-limiting inhumans; therefore, both desaturated PUFAs have therapeutic uses(Horrobin, 1992; Guil-Guerrero, 2007; Whelan, 2009). In thiscontext, alternative oils have been marketed for a long time assuitable sources thereof: borage (Borago officinalis), eveningprimrose (Oenothera biennis) and blackcurrant (Ribes nigrum) forGLA (Horrobin, 1992; Kapoor and Nair, 2005), and likewise fish oilsfor EPA + DHA (Das, 2006).

Recently, a SDA-containing oil has been authorized as NovelFood (approval 2008/558): Echium plantagineum (Paterson’s curse)seed oil. This oil, which is known as ‘‘the plant based alternative formarine oils’’, contains both GLA and SDA as well as a highpercentages of ALA. Furthermore, the absence of unsafe compo-nents has been reported (The Commission of the EuropeanCommunities, 2008). Unfortunately, it shows an average percent-age of SDA quite low (12–13% of total FAs) (Guil-Guerrero, 2007),which is a drawback when attempting to get the daily needsof EPA + DHA from E. plantagineum oil, because the metabolic

J.L. Guil-Guerrero et al. / Journal of Food Composition and Analysis 31 (2013) 20–23 21

synthesis of EPA starting from SDA yields only about 25% (Guil-Guerrero, 2007; Whelan, 2009). Therefore, when its consumptiontakes place as an alternative to fish oil, the amount of oil requiredto fulfill the daily allowances for EPA + DHA needs to be increasedaccording to this observation, and thus the identification of richersources of SDA is desirable.

This work reports on the FA profile of new seed oils of severalspecies collected from their natural habitats in North Africa(Maghreb), the typical area of speciation of Boraginaceae, which isthe most promising botanical family when bioprospecting for oilsrich in n-3 and/or n-6 C18-PUFAs (Guil-Guerrero, 2007). This is thefirst research on the FA profile of the seed oils from Cynoglossum

dioscoridis, Myosotis discolor, Echium parviflorum, E. sericeum,Arnebia decumbens and Heliotropum bacciferum. Other speciessuch as B. officinalis and E. plantagineum, which are currentlycommercially grown for oilseed production, have been collected toanalyze FA profiles in wild specimens.

2. Materials and methods

2.1. Samples

Seeds were collected from their natural habitats in Morocco andTunisia (Table 1). Seeds were cleaned, labeled and stored in dryconditions until analysis. For each species and location shown inthe table, seeds were obtained from plants collected in threedifferent areas. The seeds were ground in the lab with the aid of amortar. From these, appropriate amounts were taken (usually150–200 mg) for direct methylation and further GLC analyses(three samples from three areas per species). Each one wasanalyzed in triplicate.

2.2. Oil extraction and transesterification

Simultaneous oil extraction and transesterification was doneaccording to previous works (Lepage and Roy, 1984). Ground seeds(10 mg) were mixed in 10 ml-test tubes with 1 ml of themethylation mixture (methanol:acetyl chloride 20:1 v/v) and1 ml of n-hexane, and heated at 100 8C for 30 min. Then, the tubeswere cooled to room temperature. 1 ml of distilled water wasadded and after centrifugation (3500 rpm, 3 min), the upperhexane layer was removed for GLC analysis.

2.3. FA analyses

FA methyl esters (FAMEs) were analyzed using a Focus GC(Thermo Electron, Cambridge, UK) equipped with a flame ionizationdetector (FID) and an Omegawax 250 capillary column (30 m �0.25 mm i.d. � 0.25 mm film thickness; Supelco, Bellefonte, USA).The temperature program was: 1 min at 90 8C, heating until 220 8C ata rate of 10 8C/min, constant temperature at 220 8C (2 min), heatinguntil 250 8C at a rate of 10 8C/min and constant temperature at 250 8C(1 min). The injector temperature was 250 8C with a split ratio of50:1. The injection volume was 4 ml. The detector temperaturewas 260 8C. Nitrogen was used as carrier gas (1 ml/min).

Peaks were identified by retention times obtained for knownFAME standards (PUFAs No. 1, 47033; methyl g-linolenate 98.5%purity, L6503; and methyl stearidonate 97% purity, 43959 FLUKA)from Sigma, (St. Louis, USA), while FA contents were estimated byusing methyl pentadecanoate (15:0; 99.5% purity; 76560 Fluka)from Sigma as internal standard.

2.4. Quality control

The repeatability of the direct methylation was checked byanalyzing replicates of the same sample daily. The intermediate

precision was evaluated by measuring samples on different daysthroughout the study. Also, blank samples were analyzed everytime when the methylations were done.

Control oil samples were analyzed prior and after runningsamples. The control oil was Canola oil, 46961 SUPELCO, fromSIGMA. As quality control of GLC, a blank sample (hexane) wastested for every batch in GLC.

Experiments for all samples were conducted in triplicate.Results are expressed as mean value � S.D. in Table 1.

3. Results and discussion

The basic data relating to the collected samples and their FAprofiles are included in Table 1. On total FAs, the highestpercentage of GLA was found in the seed oil of B. officinalis

(19.5%, sample 3) followed by E. sericeum (18.9%, sample 16). Withregard to SDA, the highest percentage was found in the seed oil ofE. parviflorum (17.3%, sample 15), ranging in E. plantagineum

samples from 9.6% (sample 9), to 15.5% (sample 8). Consideringthe healthy effects arising from the intake of essential FAs, whichcorrespond to the sum of GLA + SDA content (Whelan, 2009; Guil-Guerrero, 2007), stands out sharply E. sericeum (30.9%, sample 16),followed by E. plantagineum (26.3%, sample 8). On the other hand,looking to the total amount of FAs in seeds, GLA reaches 5.6% onseed weight in B. officinalis (sample 3), while for SDA E. parviflorum

was the most prominent species, with 2.2% (sample 15). However,the above given figures are not inherent to these species, takinginto account that the oil content in Echium seeds can be easilymodified by agronomic practices or culture lines selection (Bertiet al., 2007).

The percentage of SDA found in E. parviflorum, higher than thatshowed by the cultivated E. plantagineum, could provide nutri-tional benefits. In this sense, the recommended daily intake of250 mg EPA + DHA made for the general population to reduce therisk of coronary heart disease (Musa-Veloso et al., 2011), can befulfilled with approximately 1 g of fish oil (9 kcal). Therefore, byconsidering the above mentioned conversion rate among SDA andEPA, 8.3 g of E. plantagineum seed oil (75 kcal) or 5.8 g of E.

parviflorum seed oil (52.3 kcal) could also provide the requireddaily amounts of EPA + DHA.

Once the high level of SDA in the seeds of E. parviflorum

collected in Tunisia was confirmed, this species was also gatheredin Alicante (Spain) to compare SDA percentages between plantsfrom different areas. The analyses of several samples showed thatthe Spanish seeds have similar FA profiles than those from Tunis.Nevertheless, for Spanish seeds SDA ranged between 11.6 and14.6%, while for Tunisian seeds it reached 17.3%, both on total FAs.Thus, different chemotypes were detected, which suggest that thisspecies might have higher SDA amounts in other areas, able toprovide more valuable oils.

B. officinalis and E. plantagineum, species which are farmednowadays, show a great variability in their PUFA content whengrown wild: in B. officinalis the GLA range is between 13.6 and19.6%, while in E. plantagineum the interval is 8.9–13% for GLA, and9.6–15.5% for SDA, both on total FAs. This fact indicates that thesearch of wild chemotypes could be a simple and effective tool toimprove the level of PUFAs in the cultivated species.

As noticeable results of the present work, an oilseed species richin GLA (E. sericeum) and other one in SDA (E. parviflorum) have beencharacterized. Assuming that some important factors could besolved properly, such as the bioavailability of FAs and adaptation ofthese plants to be farmed, both of them could constitutealternative cultures in drylands, if functional oils production isdesired. Also, they could be used as oil sources to obtain GLA and/orSDA concentrates or purified extracts. The high level of SDA foundin E. parviflorum, unpublished until now, allows us to consider this

Table 1Fatty acid profiles of seed oils from Boraginaceae species collected from the Maghreb region. Values are expressed as percentages of total FAs (mean values� SD of three different populations for sample).

Sample

identification

Species Herbarium

code

Location Total FAs Main fatty acids (area% on total detected area)a

Latitude Longitudes Area g 100 g�1 16:0 18:0 18:1n-9 18:2n-6 18:3n-6 18:3n-3 18:4n-3

Boraginaceae (Morocco)1 Anchusa azurea Mill. HUAL 22714 35.454 N 5.495 W Road Tetuan-Chauen 14.0�1.6 10.2�0.5 2.2�0.1 26.8�0.2 38.5�1.3 11.6�0.4 n.d.b n.d.

2 Borago officinalis L. No sample 35.203 N 5.311 W Near Chauen 29.4�2.2 11.4�0.2 6.4�0.3 26.6�1.0 34.6�0.6 13.5�1.0 0.9� 0.1 n.d.

3 Borago officinalis L. HUAL 22710 35.791 N 5.642 W Near Tanger 28.9�2.4 11.7�0.4 4.4�0.2 19.8�0.4 36.8�0.1 19.5�0.1 n.d. n.d.

4 Cynoglossum creticum Mill. HUAL 22711 35.899 N 5.477 W Ksar-es-Seghir

(road Ceuta-Tanger)

25.9�3.1 6.3�0.2 1.2�0.1 51.7�0.8 2.0�0.2 n.d. 13.5�1.3 2.1� 0.1

5 Cynoglossum dioscoridis Vill. HUAL 22709 35.123 N 5.132 W Bab Taza

(Talassemtan Nat. Park)

4.1� 0.5 17.9�0.4 3.7�0.1 26.2�0.3 28.2�0.3 3.6�0.1 14.2�0.3 2.6� 0.1

6 Echium creticum L. HUAL 22699 35.454 N 5.495 W Road Tetuan-Chauen 19.7�2.1 5.9�0.2 2.6�0.1 12.5�0.4 12.5�0.4 6.4�0.1 47.2�0.4 12.3� 0.5

7 Echium modestum Ball HUAL 22705 34.271 N 6.642 W Sidi ben Ghaba

(north Rabat)

16.9�2.4 6.2�0.1 2.6�0.2 12.7�0.4 18.0�0.3 10.9�0.0 37.5�0.1 11.7� 0.0

8 Echium plantagineum L. HUAL 22702 35.899 N 5.477 W Near Ksar-es-Seghir

(road Ceuta-Tanger)

15.5�3.1 8.6�0.6 2.6�0.1 11.2�0.3 13.4�0.6 10.8�0.5 37.2�1.8 15.5� 0.4

9 Echium plantagineum L. HUAL 22703 35.899 N 5.477 W Near Ksar-es-Seghir

(road Ceuta-Tanger)

17.4�1.5 8.3�0.5 3.7�0.1 21.3�0.3 18.5�0.7 10.3�0.5 27.6�0.4 9.6� 0.1

10 Echium plantagineum L. HUAL 22704 35.528 N 5.839 W Mharhar swamp,

West Jebala

15.8�2.3 10.5�0.5 2.6�0.2 11.4�0.1 16.8�0.7 13.0�0.9 32.5�2.0 12.6� 0.3

11 Echium plantagineum L. HUAL 22708 34.298 N 6.393 W La Mamora 16.5�1.9 9.5�0.2 3.0�0.2 18.3�1.0 18.8�0.2 11.6�0.6 28.5�0.5 10.5� 0.5

12 Echium plantagineum L. HUAL 22700 35.579 N 5.629 W Near El Fendek

(road Tanger-Tetuan)

17.1�1.8 7.4�0.3 3.0�0.0 12.5�0.4 16.8�0.1 10.5�0.5 37.2�0.2 12.0� 0.1

13 Echium plantagineum L. HUAL 22701 34.151 N 4.005 W Near Taza, Jbel Tazzeka 16.8�2.0 6.7�0.4 3.0�0.2 16.6�0.1 14.5�0.7 8.9�0.2 37.1�0.4 12.7� 0.3

14 Myosotis discolor Pers. subsp.

dubia (Arrond.) Blaise

HUAL 22716 35.108 N 5.138 W Bab Taza

(Talassemtan Nat. Park)

14.6�3.7 12.1�0.5 2.8�0.2 23.7�0.2 30.8�0.2 7.4�0.0 7.1� 0.3 5.4� 0.5

Boraginaceae (Tunisia)15 Echium parviflorum Moench. HUAL 23085 36.856 N 10.333 E Carthaghe 12.7� 0.8 6.6�1.2 3.0�0.2 8.9�0.7 10.1�0.1 7.1�1.2 47.6�3.0 17.3� 0.9

16 Echium sericeum Vahl. HUAL 23087 36.856 N 10.333 E Carthage 3.8� 0.8 12.2�1.8 3.1�0.2 8.2�0.8 24.6�0.1 18.9�0.7 20.1�1.6 12.0� 0.4

17 Arnebia decumbens (Vent.)

Coss.Kral.

HUAL 23086 32.893 N 10.077 E Near Tataouine 8.1�1.3 9.1�0.3 2.2�0.1 21.3�0.1 15.7�0.6 6.3�0.2 31.3�1.0 12.4� 0.1

18 Arnebia decumbens (Vent.)

Coss.Kral.

HUAL 23092 32.915 N 10.278 E Chenini 3.2� 0.1 13.2 �0.6 2.2 �0.1 14.8�0.2 27.2 �0.9 10.0 �0.3 21.2�0.8 9.6 �0.3

19 Nonea vesicaria (L.) Cheichen HUAL 23088 33.875 N 10.888 E Houmt-Souk 22.8� 0.6 12.0�0.2 3.4�0.1 25.6�0.3 43.9�0.9 11.8�0.0 1.2� 0.2 0.3� 0.0

20 Heliotropum bacciferum Forssk. HUAL 23089 33.875 N 10.888 E Houmt-Souk 1.0� 0.1 18.6�2.1 3.4�0.1 15.8�0.2 54.9�3.2 1.2�0.6 6.3� 0.8 n. d.

a Other minor amounts of FAs accounted for 100%.b n.d.: no detected.

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J.L. Guil-Guerrero et al. / Journal of Food Composition and Analysis 31 (2013) 20–23 23

oil as a suitable candidate for fish oil replacement, instead thehitherto cultivated E. plantagineum.

Acknowledgment

The authors thank the Spanish Ministry of Science andTechnology (project AGL2011-25807) for financial support.

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