Industrial Crops and Products, 1 (1992) 31-34 31 r) 1992 Elsevier Science Publishers BY All rights reserved, 0926-6690/92/S05.00 INDCRO 00005 Composition of seed oils in some Latin American Cuphea (Lythraceae) Shirley A. Grahama and Robert Kleimanb 'Departmelll ojBiological Sciences, Kelll State University, Kent, OH, USA ancfbUSDA-ARS, Northern Regional Research Celller, Peoria, IL, USA (Received 26 August 1991: accepted 13 February 1992) Abstract Graham, S.A. and Kleiman, R., 1992. Composition of seed oils in some Latin American Cuphea (Lythraceae). Industr. Crops Products, I: 31-34. Cuphea is unique among all flowering plants for the diversity ofmedium chain fatty acids produced as dominant fatty acids in the seed oils. The genus is a focus of research as a renewable source of MCTs for use by the chemical, food and health industries and as a model organism for the elucidation of biosynthesis of fatty acids, Seed oil composition is reported in 15 taxa, including 13 species previously unstudied, Results mostly substantiate patterns established in earlier studies in which species emphasize production of a single fatty acid, either C8:0, CIO:O, CI2:0, C14:0 or CI8:2. Three species are unusual in producing equal amounts ofC8:0 and CIO:O, C12:0 and C14:0, and ClO:0-CI2:0-CI4:0, respectively, In C. pulcherrima, 94% of total seed oil composition is caprylic acid (C8:0) and in C. schumannii, 94% is capric acid (ClO:0). These are the highest single fatty acid percentages reported in the genus, Representatives ofsect. Ornithocuphea are analysed for the first time and new compositional seed oil patterns are reported in sections Brachyandra and kIelvilla. Seed oil; Latin American Cuphea The New World genus Cuphea is currently included weight, most commonly with 30-33% oil content in a select list of flowering plant genera that show (Arkcoll, 1988; Thompson and Kleiman, 1988), exceptional promise as new industrial crop plants The value of Cuphea seed lipids lies in the composi­ (Hinman, 1986; Knapp, 1990; ThomI1son, 1984), tional diversity produced and the utilization that Seeds of Cuphea produce oils composed of a can be made of the various fatty acids by the diversity of medium-chain fatty acids, with indivi­ chemical, food and health industries, The primary dual species usually emphasizing one of several medium chain fatty acid in use at present is lauric fatty acids, Cuphea oilseeds may be rich in caprylic acid, It is employed extensively in the manufacture (C8:0), capric (ClO:O), lauric (C12:0), myristic of food products, household cleaners and personal (C14:0), linoleic (C18:2) or, occasionally, linolenic care products, in industrial lubricants, and in acid (C18:3), The lipids occur primarily in the coatings and plastics (Knaut and Richtler, 1985), embryo and constitute up to 42% of total seed About one billion pounds of lauric oils are imported annually by the United States for such Correspondence: Shirley A. Graham, Department of Biological uses (Kleiman, 1990), Of recent development are Sciences, Kent State University, Kent, OH 44242, USA. structured lipid mixtures in which linoleic acid (typically predominate in plant seed oils) is blended plant fatty acid, together \vith the nearly regular with shorter chain fatty acids, which ClIplzea seeds (vs. irregular or zygomorphic) flowers characteris­ produce in abundance. Such formulations are tic of the section, suggests that the most primitive employed to improve digestion in newborns, for species of the genus occur in section ClIplzea. weight control in obese patients, and in other In section Braclzyandra, C. micrantlza. with two specific nutritional medical applications (Babayan, major fatty acids (CI2:0=47% and CI4:0=40%), 1981, 1987). Because of the unique diversity of differs from a previously reported population in fatty acids produced among the species, ClIplzea is which lauric acid dominated (CI2:0=53%) and also viewed as a model system for the study of the myristic acid was secondary (CI4:0= 18%)(Gra­ fatty acid biosynthetic mechanism (Slabas et al., ham et al., 1981). The first population is from 1982: Deerberg et aI., 1990), while isolation of the Dominican Republic, the latter from Brazil. Most genes that control the system is a goal of biotech­ species of ClIplzea are represented by one dominant nology firms seeking to transfer fatty acid synthesis fatty acid in the seed oil, and only occasionally by genes to established oilseed plants such as rape two. In only one species to date, C. micropetala (Graham, 1989a). var. hirtella, three fatty acids occur in approxi­ Seed oil composition patterns of 73 species of mately equal proportions. Where several popula­ ClIplzea or ca. 28% of the genus have been deter­ tions of one species have been analysed, minor mined (Graham et al., 1981; Wolf et al., 1983: variation of 10% or less normally occurs in percen­ Graham and Kleiman, 1985) and are summarized tage of fatty acids produced, rather than major by Graham (1989a). Fifteen new analyses are variations such as reported here for C. micrantlza. reported here, including analyses of 13 previously C. micropetala (sect. Melvilla) appears to have unstudied taxa in six of the fourteen sections of two compositional patterns, one in each variety of the genus. the species. In var. hirtella three dominant fatty acids, CI0:0, C12:0 and CI4:0, occur in approxi­ Materials and Methods mately equal amounts; in var. micropetala, one of the three, CI4:0, is predominant. Seeds for analysis were collected in Brazil. Bolivia, The section Melvilla is considered polyphyletic Dominican Republic, Mexico and Venezuela. Her­ based on diversity of pollen types and floral charac­ barium vouchers are deposited at Kent State Uni­ versity (KE-G). Analysis follows procedures ters such as spur shape and calyx lobe types outlined earlier (Wolf et al., 1983). After transester­ (Graham and Graham, 1971; Graham, 1990 and ification to their methyl esters, fatty acids of the unpublished data). Seed oil composition patterns wild seeds were determined by gas-liquid chroma­ support the presence of at least three major lin­ tography, and content of single fatty acids was eages. Lineages of CI0:0 and C 12:0 species were computed as percentage of the total fatty acids. previously reported (Graham, 1989a). The addition of C. micropetala var. micropetala, C. rasilis, C. Results and Discussion salvadorensis with C14:0 seed oils suggests presence of a third group of related species. Evidence for Fatty acid composition of seed oils in 15 taxa of relationships using seed oil composition is welcome ClIplzea is summarized in Table I. The species in this section where convergence of the most generally follow patterns reported for previous prominent floral characters as a result of similar species analysed. They are congruent with patterns specialized pollinators (hummingbirds, hawk­ of related species in most, but not all, instances. moths, long-tongued bees) makes determination Among the taxa reported, the following deserve of relationships difficult. Differences in composi­ special comment. In C. denticlilata seeds primarily tion patterns are thus valuable in assessing evolu­ produce linoleic acid (C18:2), the most common tionary relationships among the species. constituent of flowering plant seed lipids. Domi­ In the evolutionarily advanced sect. Diplop­ nance of C18:2 in C. denticlilata is in keeping with tychia, seed oils of C. ianthina are unique in having the pattern in section Cliphea (see summary: Gra­ nearly equal amounts of C8:0 and CIO:O. The ham, 1989a). The emphasis on this most common same pattern is reported for C. pinetorllm in this 33 TABLE I Fatty acid composition of Cuphea seed oils expressed as percentages of total fatty acid composition. Species are arranged according to the classification of Koehne (1903) Species Percentage of total fatty acids (%) Collection 8:0 10:0 12:0 14:0 16:0 18 :0 18: I 18:2 18:3 Sect. Cuphea C. dellliculala Kunth 0.0 0.0 0.0 0.0 33.0 0.4 9.8 53.2 3.5 Venezuela: Fryxel/ 4381 Sect. Brachyalldra C. me/anium R.Br. 0.0 4.7 85.9 7.6 0.9 0.0 0.2 0.7 0.0 Dom. Republic: Zanoni 38177 C. micralll!w Kunth 0.0 0.6 47.0 40.0 6.1 0.1 ...' ~0 3.8 0.0 Dom. Republic: Zanoni 41271 C. urens Koehne 0.0 20.1 75.6 3.0 0.3 0.0 0.3 0.7 0.0 Dom. Republic: Zanoni 41811 Sect. Elialldra C. acin!folia St.Hil. 4.6 12.5 65.1 10.7 1.8 0.1 1.9 3.1 0.2 Brazil: Graham 951 C. con(enif!ora St.Hil. 3.0 15.2 73.3 3.7 1.0 0.1 0.9 2.6 0.1 Brazil: Graham 927 Sect. MeMlla C. micropetala var. micropetala Kunth 0.0 17.0 23.7 47.8 5.1 0.2 1.9 4.2 0.1 Mexico: Graham 1051 J 0 var. hirtel/a Koehne 0.0 22.3 27.1 38.7 4.1 0.2 _.~ 4.9 0.4 Mexico: Graham 1048 C. rasilis Graham 0.0 13.0 23.7 49.0 5.0 0.3 3.6 5.1 0.2 Mexico: Graham 1027 C. salvadorensis Stand. 25.3 0.9 2.8 64.5 5.2 0.0 0.5 0.5 0.3 Mexico: Graham 1076 C. schumannii Koehne 3.0 93.8 1.0 0.1 0.6 0.1 0.3 1.0 0.1 Mexico: Graham 1090 Sect. Diploptychia C. cyanea DC. 68.3 29.8 0.1 0.0 0.4 0.0 0.6 0.7 0.1 Mexico: Graham 1070 C.