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Arquette, J.G. and J.H. Brown. 1993. Development of a cosmetic grade oil from Lesquerella fendleri seed. p. 367-371. In: J. Janick and J.E. Simon (eds.), New crops. Wiley, New York.

Development of a Cosmetic Grade Oil from Lesquerella fendleri Seed

James G. Arquette and James H. Brown


  1. AGRICULTURE
  2. OIL EXTRACTION
  3. LABORATORY REFINING PROCEDURE
  4. LESQUERELLA MEAL
  5. PHYSICAL PROPERTIES
  6. STABILITY
  7. TOXICOLOGY
    1. Acute Oral Toxicity (Single Dose)
    2. Eye Irritation Test (Draize)
    3. Primary Dermal Irritants
    4. Comedogenicity
    5. Allergenicity
  8. FUTURE PROSPECTS
  9. REFERENCES
  10. Table 1
  11. Table 2
  12. Table 3
  13. Table 4
  14. Fig. 1

Lesquerella fendleri L., Brassicaceae, is an annual native to the arid southwestern United States and has been under study by the USDA Agricultural Research Service since the 1960s. The fatty acid composition of the oil is a blend of lesquerolic acid, a C-20 monounsaturated hydroxy acid, and highly unsaturated C-18 fatty acids. As such, lesquerella oil represents an alternative to castor oil as a source of hydroxy fatty acids. Both the similarities and differences with castor provide a stimulus for application trials involving lesquerella. Initial testing of lesquerella oil indicate extremely low levels of toxicity or irritation (oral, dermal, and ocular). The lesquerella meal resulting from oil extraction is rich in protein and is being evaluated as a source of natural antioxidants, gums, colorants as well as animal feed. A low volume specialty oil market, such as cosmetics, has been identified for product development and is the subject of this paper.

AGRICULTURE

Lesquerella is a New World genus of over 70 species (Gentry and Barclay 1962). Producing abundant nonshattering seed, the species, L. fendleri, has been found to have superior agronomic potential. The species is native to the states of Arizona, New Mexico, Oklahoma, and Texas and found in regions of poor soil and low rainfall (25 cm/yr). Its low water demand may make it an attractive potential substitute for certain heavily irrigated crops in these regions. Current seed yields of 950 to 1,120 kg/ha and the 21% seed oil content must still be improved through breeding and agricultural practices.

OIL EXTRACTION

The cosmetics industry desires a solvent free product and often stipulates that the processing be solvent free. For this reason, the lesquerella seed is being cold press extracted. The seed is preconditioned in a steam tube drier modified to allow contact with live steam. The oil is then mechanically extracted from the seed. This system of crushing lesquerella seed produced favorable results with a crude yield of 85% of available oil. The crude oil contained an excessive amount of gums that were unfilterable and did not decant upon washing. Centrifugal degumming is required. Gum contamination of the oil can be minimized by controlled conditioning of the seed prior to extraction. As more seed becomes available, cold press extraction followed by solvent extraction of the meal will provide maximum yields and deliver both a solvent free oil for cosmetic applications and a solvent extracted oil for other industrial applications.

LABORATORY REFINING PROCEDURE

Crude lesquerella oil is the color of molasses, often too dark to measure with a Lovibond Tintometer 1" cell. The oil also posses a distinct odor. Both the color and odor must be reduced for cosmetic applications.

Refining of lesquerella has been limited to laboratory studies until now. Crude oil decanted from the gums was filtered. Free fatty acid content was reduced by spraying 0.7% excess 16°. Bé sodium hydroxide over the top of the oil at room temperature. After 1 h the temperature was raised to 65°C for 5 min. Heat was then turned off, allowing the soap stock to break and settle. The oil was decanted, water washed, and dried under vacuum. Bleaching consisted of addition of 10% Filtrol 160 at 90°C for 20 to 30 min with good agitation and under vacuum. Activated carbon and Trisyl have been used as bleaching agents without significant improvements. Laboratory deodorization consisted of steam sparging at 220° to 230°C for 2 h at 5 mm Hg pressure.

The procedure described above followed conventional oil refining procedures and did not result in any significant reduction in hydroxyl content. As more oil becomes available, investigations will continue to determine the effects of using neutral bleaching clays and physical refining to remove free fatty acids and odor simultaneously.

This process produced a superior quality oil of good color but with a slight residual odor. Large scale continuous deodorization equipment must be examined in an effort to further reduce odor levels.

LESQUERELLA MEAL

The meal resulting from oil extraction has an excellent distribution of amino acids being particularly high in lysine (Carlson et al. 1990). Preconditioning the seed is necessary for deactivation of the thioglucosidase enzyme system so that the meal can be used for animal feed. Meal feeding studies are in progress for a variety of livestock. Unlike castor, lesquerella does not contain toxic moieties like the very lethal protein, ricin; the poisonous alkaloid, ricinine; or the very potent allergen, CB-1A. There is significant interest in the lesquerella meal as a source of natural antioxidants, pigments, gums, and protein extracts as well as for animal feed.

PHYSICAL PROPERTIES

The L. fendleri seed contains approximately 21% triglyceride oil with nine fatty acids (Table 1). Moisture content at harvest was 5 to 6%.

Current breeding programs need to increase both the oil content of the seed and the lesquerolic acid content of the oil. The highly unsaturated fatty acid portion resembles linseed oil and contributes significantly to the characteristics of the oil and unique derivative potential. The structure of lesquerolic acid, 14-hydroxy, cis-11-eicosenoic acid bears a close relationship to ricinoleic acid found in castor oil (Fig. 1). Table 2 presents physical properties of the cold pressed and refined oils currently being produced.

STABILITY

Lesquerella oil contains an almost equal blend of highly unsaturated fatty acids and hydroxy unsaturated fatty acids. As oxidative stability of an oil tends to be inversely proportional to the degree of unsaturation, tests were conducted to determine the relative stability of lesquerella oil (Table 3). The AOCS Method Cd 12-57 was used to determine the stability of the oil under prescribed conditions. In this case, active oxygen method (AOM) hours to an endpoint of 100 meq/kg are reported. The oils selected for examination were provided by Jojoba Growers and Processors Inc. The tests were conducted by Henkel Corp., supplier of the mixed tocopherol antioxidant, Covi-Ox. Covi-Ox is a registered trademark of the Henkel Corp.

Cashew and Brazil nut oil were included in the study as they have comparable Iodine Values. The results indicate that Lesquerella oil is stable beyond what might be expected given the Iodine Value of 106. Whether lesquerella might be a source for new potent natural antioxidants warrants further study.

TOXICOLOGY

Acute Oral Toxicity (Single Dose)

The acute single dose oral toxicity was determined on Sprague-Dawley rats. Lesquerella oil was found to have an apparent LD50 Single Oral Dose of greater than 15 g/kg of body weight. No larger dosages are administered in this test. Lesquerella, according to this test, achieved the lowest rating of "Practically Non-Toxic" (Gleason et al. 1969). Of the ten animals tested, three females exhibited a slight weight loss during the first week, but all animals went on to show positive weight gain by the end of the test period with no other signs of toxicity. The observation criteria is extensive. Noteworthy was the lack of diarrhea at these high dosages indicating that lesquerella is no substitute for castor oil in the purgative market.

Eye Irritation Test (Draize)

The extent of eye irritation was determined in New Zealand rabbits. The highest mean score was 0.0. No positive reactions were exhibited in any of the six animals. Lesquerella oil was rated as Non-Irritating and passed the eye irritation test. For all seven potential ocular reactions monitored, the results were consistently zero (lowest possible) for the entire 72 h test period.

Primary Dermal Irritants

The degree of irritation (erythema-eschar and edema) elicited by the lesquerella oil was determined on the abraded and non-abraded skin of six New Zealand white rabbits over a 72 h observation period. The Primary Dermal Irritation Score was 1.67 (mild irritant) and is not considered to be a Primary Dermal Irritant. At the 24 h observation, three animals exhibited well defined erythema and three animals exhibited very slight erythema. At the 48 h observation, five animals exhibited well defined erythema and one very slight erythema. All six animals exhibited no edema.

Comedogenicity

This test (Morris and Kwan 1983) is designed as a screen for any material which may be a potential acnegen. The test is conducted on the ear canals of four New Zealand white rabbits which are inspected for comedomes (acne) whose size is proportional to the potency of the test substance. Lesquerella oil's Comedogenic Grade is 0.0, noncomedogenic. This test is critical for cosmetic ingredients. Since the 1980s formulators have carefully selected ingredients to reduce the possibility of "acne cosmetics," the technical name for acne attributed to makeup, skin, and hair care products. The unequivocal low result will promote applications' studies within the cosmetics industry.

Allergenicity

This test (Magnusson and Kligman 1969) is designed to determine if a given material causes allergenic responses. Albino guinea pigs are used with positive and negative controls. Intradermal injections and topical applications were used. No allergenic responses were observed in the ten test animals (or in the two unsensitized and two negative controls, the two positive controls exhibited positive allergenic response). The test showed 0% sensitization. A 0 to 8% sensitization is considered Grade I, Non-sensitizing or at most a weak agent. The summary of toxicological testing conducted to date is presented in Table 4.

These toxicological test results indicate an extremely low potential for irritation. For use as a cosmetic material, this is extremely important. Lesquerella has potential for broad based application (e.g. stick deodorant, lip and eye care products, soaps, etc.) including pharmaceutical applications.

FUTURE PROSPECTS

While optimum genetic material and agronomic practices are still a few years from realization, the immediate potential for lesquerella oil and its derivatives as raw materials for the cosmetic industry appears very promising. Studies are underway to improve oil processing technology for optimum quality and yields. Initial examinations of partially and selective hydrogenated lesquerella oil have produced derivatives with very distinct properties. Formulation work has begun incorporating lesquerella oil into lip care products. Lipstick, which may contain as much as 80% castor oil, provides an initial focus for lesquerella. Lipstick has been successfully manufactured using lesquerella oil instead of castor oil. Product evaluation will begin in early 1992.

REFERENCES


Table 1. Fatty acid composition of Lesquerella fendleri seed oil.

Fatty acid Concentration (%)
Palmitic C 16:0 1.3
Palmitoleic C 16:1 0.7
Stearic C 18:0 2.1
Oleic C 18:1 18.1
Linoleic C 18:2 9.3
Linolenic C 18:3 14.0
Arachidic C 20:0 0.2
Gadoleic C 20:1 1.2
Lesquerolic C 20:1(OH) 51.4


Table 2. Physical properties of crude and refined lesquerella oil.

Property AOCS Method Crude Refined
Iodine value Cd 1-25 107 104
Hydroxyl value Cd 4-40 102
Free fatty acid Ae 4-52 1.5 0.7
Color (5.25" Lovibond Cc 136-45 too dark 4.1R; 37Y
Gardner) 14 5
Saponification number Cd 3-25 168
Peroxide values Cd 8-53 1.6 0.40
Refractive index 40°C 1.4719 1.4710
Phosphorous (ppm) Ca 12b-87 0.41
Metals (ppm): Ca 15-75
Fe 0.1
Mg 0.16
Cu 1.1
Ni 0.08
Ca 1.9


Table 3. Relative stability of triglyceride oils with added antioxidants.

Oil Iodine
value
Tocopherols
(ppm)
AOM (h)z Increased
stability
(%)
Cashew 87 0 13 ---
365 20 54
1050 27 108
Brazil Nut 101 0 10 ---
360 13 30
930 16 60
Lesquerella 106 0 35 ---
375 40 14
915 46 31
zActive oxygen method, AOCS Method Cd 12-57.


Table 4. Toxicological test results for cold pressed lesquerella oil.

Test Results
Acute oral toxicity LD50 Single Dose > 15 g/kg body wt.
Eye irritation (Draize) 0.0, Non-Irritating
Primary dermal irritation 1.67, Mild irritant, not considered a primary irritant
Comedogenicity 0.0, Non-comedogenic
Allergenicity Grade I, Non-sensitizing


Fig. 1. Structure of ricinoleic and lesquerolic acid (n = 7, ricinoleic acid; n = 9, lesquerolic acid).

Last update September 12, 1997 aw