SURVEY OF NEW SOURCES OF GAMMA LINOLENIC ACID

A. De Haro*, V. Domínguez** , A. Pujadas*** , and M. del Río*

* Institute of Sustainable Agriculture, CSIC, Córdoba, Spain

** CIFA, Logroño, Spain

*** ETSIAM, University of Córdoba, Spain

INTRODUCTION

The herbal pharmaceutical industry in Europe and USA is undergoing a major transformation from a low-tech cottage industry into a rapidly growing industrial sector.

It is estimated that global sales for 1997 totaled $16,5B, of which the largest segment was Europe (46%) followed by Asia, excluding Japan (18%), North America (18%), and Japan (15%) (Yuan, 1998).

Gamma linolenic (all-cis-6,9,12-octadecatrienoic) acid (GLA) is an essential fatty acid in increasing demand for its clinical al pharmaceutical applications. GLA supplementation in the diet by means of vegetable oils containing this fatty acid, is being employed for the treatment of health problems related to deficiencies in essential fatty acids and prostaglandins (Horrobin, 1992). Although seeds of many plants contains GLA, the most common commercial sources of GLA for pharmaceutical uses are evening primrose (Oenothera biennis L.) and borage (Borago officinalis L.). Large-scale commercial production of borage is difficult because of its indeterminate growth habit, non uniform seed ripening, and its shattering habit: a large percentage of ripened seed shatters and falls to the soil before and during harvest (Janick et al. 1989).

OBJECTIVES

1. Development of borage lines well adapted to Mediterranean conditions and with improved characteristics for GLA production.
2. To increase the natural genetic variability in borage by inducing chemical mutagenesis with Ethyl methane sulfonate (EMS).
3. Identification and selection of germplasm from others Boraginaceae species that could be used as GLA sources in semiarid conditions.

RESULTS

I) Evaluation of Spanish borage populations originating from two different sources:

a) white flowered material cultivated as vegetable in the Ebro Valley (Northern Spain) showing a wide range of variability for agronomic traits: 130 cultivars and populations (Table I).

b) blue flowered roadside populations collected in different localities of Andalucía (Southern Spain): 55 wild entries (Del Rio et al., 1993).

II) Detection and isolation of two mutants lines in borage with improved seed production in borage: mutant type B, with higher number of petals, sepals, and ovules than normal, and mutant type C, with closed or partially opened flowers that retain the seeds after maturation (De Haro and Del Rio, 1998).

III) Evaluation of Mediterranean Boraginaceae species for GLA and others fatty acids

CONCLUSIONS

I. Wild and cultivated borage show a great deal of variability for the most relevant quality traits, oil and GLA content (Table II). Entries with about 27% of GLA, oil content higher than 34% and erucic acid values lower than 2.5% have been selected. Unfortunately no variability for seed retention have been found.

II. After treatment with EMS (Ethyl methane sulfonate), two mutants with improved agronomic characteristics have been isolated, one by increasing the seed production by flower (type B), the other one by retaining their mature seeds until harvest, eliminating the seed loss due to seed shattering that characterises normal plants (Table III).

III. Several species of Boraginaceae (Anchusa, Echium, Nonea....), well adapted to Mediterranean region show high potential to be used a GLA sources in dry conditions (Table IV), and promising lines of each species have been selected for further genetic studies.

Table II

Mean and range of 1000 seed weight, oil content and fatty acid composition (%) of white and blue flowered borage populations.

N = number of entries, WF = white flowered, BF = blue flowered

Table III

Variability in flowers and seeds in untreated and mutant borage plants^a

^a Number of flowers inspected in each mutant type and in untreated plants: 50.

^b Type B : plants with flowers larger than normal and, often, with the style and stigma malformed.

^c Type B1 : plants with normal shaped style and high fertility, obtained after crossing type B plants with normal plants.

^d Type C1 : plants with flowers closed and seed retention.

^e Type C2 : plants with flowers partially opened and seed retention.

^f Means within the same row with the same letter are not significantly different. Significance was calculated by the Duncan´s Multiple Range Test (a=0.05 level).

N = number of entries

REFERENCES

De Haro, A., Del Río, M. 1998: Isolation of Chemically-Induced Mutants in Borage (Borago officinalis L.). JAOCS 75: 281-283.

Del Rio, M., and De Haro, A. 1993. Wild and cultivated Borago officinalis L. : sources of gamma-linolenic acid. Grasas y Aceites 44 :125-126.

Horrobin, D.F. 1992. Nutritional and medical importance of gamma-linolenic acid. Prog. Lip. Res., 31(2): 163-194.

Janick, J.,Simón, J.E., Quinn, J. and. Beaubaire, J. 1989. Borage: A Source of Gamma Linolenic Acid, in Cracker, L.E. & J.E. Simon (eds.). Herbs, Spices and Medicinal Plants: Recent Advances in Botany, Horticulture and Pharmacology. Oryx Press, Arizona, USA.

Yuan, R. 1998. Herbal Pharmaceutical Industry. Genetic Engineering News, 18 (19): 1, 10, 26, and 40.

LEGENDES FOR PICTURES ATTACHED:

Picture 1: Wild blue flowered borage

Picture 2: Cultivated white flowered borage

Picture 3: Mutant type B with higher number of petals, sepals and seeds than normal type

Picture 4: Mutant type C with mature seed retention.

Picture 5: Echium boissieri plant.

Picture 6: Anchusa azurea plant.

(Photographer: Antonio De Haro)

FOR FURTHER DETAILS CONTACT:
Antonio De Haro Bailón
Instituto de Agricultura Sostenible
Consejo Superior de Investigaciones Científicas
Avda. Alameda del Obispo s/n
Apartado de Correos 4084
14080 CORDOBA - SPAIN
phone: 34 957 499235
fax: 34 957 499252
e-mail: cs9habaa@uco.es
deharo@cica.es