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Brenner, D.M. 1993. Perilla: Botany, uses and genetic resources. p. 322-328. In: J. Janick and J.E. Simon (eds.), New crops. Wiley, New York.

Perilla: Botany, Uses and Genetic Resources*

David M. Brenner

  1. BOTANY
    1. Photoperiod
    2. Toxicology
  2. AGRONOMY
  3. USES
    1. Seed Oil
    2. Ornamental
    3. Culinary
    4. Volatile Oil
    5. Medicinal
  4. GERMPLASM
    1. Maintenance and Manipulation
    2. Sources
  5. CROP PROSPECTS IN THE UNITED STATES
  6. REFERENCES
  7. Table 1
Perilla [Perilla frutescens (L.) Britton, Lamiaceae] is a common annual weed of the eastern United States but considered a commercial crop in Asia. In the United States, perilla food products are available in Korean ethnic markets, and red-leafed cultivated plants are used in landscaping. The species has been used abroad in at least nine ways: seeds are sold as food for birds or human consumption; the seed oil is used as a fuel, a drying oil, or a cooking oil; the leaves are used as a potherb, for medicine, or for food coloring; and the foliage is distilled to produce an essential oil for flavoring (Publications and Information Directorate 1966).

BOTANY

Perilla is a member of the mint family and has the characteristic square stems and four stamens of most species in that family. Within the genus Perilla, the taxonomic nomenclature is controversial (Zeevaart 1969). The number of species recognized varies from one (Publications and Information Directorate 1966; Booth 1957, Koezuka et al. 1985; Misra and Husain 1987), to two (Tanaka 1976; Miller 1922), or four (Gorshkova 1954), and also includes taxonomic and horticultural varieties (Miller 1922). Historical confusion with Ocimum is briefly reviewed by Simon et al. (1984). The best diagnostic characteristics of Perilla are the net-patterned testa of the nutlets and the distinctive smell of the crushed foliage. Dry skeletons of the plants persist into the spring; their racemes retain dry papery calyces when the purple to white flowers have fallen away.

Perilla has a variable chromosome complement. Vij and Kashyap (1976) found a haploid chromosome count of fourteen, plus zero to two beta chromosomes. Yamane (1950) karyotyped four taxonomic varieties, found chromosome counts of both n = 20 and 2n =38 and distinguished three chromosome sizes.

I have seen perilla growing as a common weed of pastures and roadsides in the southeastern United States. One reason for perilla's survival in pastures, is that cattle avoid it. It stands 15 cm tall for most of the summer. In August, it blooms and its stem elongates rapidly. The plant reaches a height of approximately 1 m before being killed by frost in November.

Photoperiod

Perilla has been used by plant physiologists to investigate flower induction. The following information is modified from Zeevaart's (1969, 1985) reviews of the effect of day length on perilla. Long nights induce flowering, but different accessions have different critical night lengths. Plants become photosensitive at the fourth leaf pair stage. Flowering starts 18 to 20 days after the start of long nights. After 30 long nights, plants will bloom until they die, regardless of subsequent day length. Scions from an induced plant can induce flowering of the stock plant onto which they are grafted. Wada and Totsuka (1982) discovered another environmental influence on blooming. They forced perilla to bloom with continuous lighting by restricting nitrogen availability. I have observed plants in Ames, Iowa, that bloomed during short nights evidently because of transplanting shock.

Toxicology

Perilla is ordinarily avoided by cattle but has been implicated in cattle poisoning (Phillips and Von Tungein 1986). Plants are most toxic if cut and dried for hay late in the summer, during seed production (Kerr et al. 1986). Wilson et al. (1977) isolated the toxin "perilla ketone," which causes pulmonary edema (fluid in the lung cavity) in many animal species, although not in pigs or dogs (Garst et al. 1985). In Japan, 20 to 50% of long-term workers in the perilla industry develop dermatitis on their hands due to contact with perillaldehyde (Okazaki et al. 1982).

AGRONOMY

Perilla was never grown commercially as an oilseed in the United States, although several agronomists investigated the crop (Fox 1911; Gardener 1917, 1926; Rabak and Lowman 1945; Fuelleman and Burlison 1944; Weibel and Burlison 1948). Perilla was also experimentally grown as a crop in many parts of the British empire (Imperial Institute 1920, 1926). In contrast, production has continued in Korea (Yu and Oh 1976; Choi et al. 1980).

Fox (1911) and Gardener (1926) calculated the economic return from production of perilla as an oilseed in the United States, and found it unprofitable in comparison with linseed. Rabak and Lowman (1945) determined that although perilla is well adapted to the climate of the southeastern United States, it will be unprofitable unless seed shattering can be controlled.

Dwarf, early seed maturity types were developed in Illinois for short-season climates (Fuelleman and Burlison 1944; Weibel and Burlison 1948). Seed yields ranged from 220 to 1,400 kg/ha in Illinois research plots (Weibel and Burlison 1948), 1,020 to 1,440 kg/ha in Korean research plots (Choi et al. 1980), and 1,110 to 1,670 kg/ha in Japanese agricultural production (Imperial Institute 1920).

USES

Seed Oil

The seeds of perilla contain 31 to 51% of a drying oil similar to tung or linseed oil (Jamieson 1943). All drying oils leave a hard protective surface when dry. Perilla oil has been used as a drying oil in paints, varnishes, linoleum, printing ink, lacquers, and for protective waterproof coatings on cloth. It has also been used for cooking, and fuel (Publications and Information Directorate 1966). The spent seed meal can be fed to ruminants (Folger 1937). The oil is very unsaturated, with an iodine number of 185 to 208, and includes linolenic, linoleic, and oleic acids (Jamieson 1943; Eckey 1954; Publications and Information Directorate 1966; Park et al. 1981). One contrasting study reported a much lower iodine number, of 138 (Tsuyuki et al. 1978). Trocopherols in perilla oil reduce oxidation (Kashima et al. 1991).

The United States' importation of perilla seed oil peaked at more than two million dollars in 1939; the last report of oilseed importation was in 1943 (United States Department of Agriculture 1954). The supply was interrupted during World War II (Rabak and Lowman 1945). In Korea, the seed oil continues to be produced for cooking and industrial uses (Choi et al. 1980). Local oilseed production has also continued in Bhutan, where R.P. Croston and T. Dorji collected a seed oil accession (PI 481703) for the International Board for Plant Genetic Resources in 1981.

Ornamental

In 1922, six ornamental cultivars were listed by Miller, in whose time perilla was declining in importance: "Before the introduction of the Coleus this plant was much used as an ornamental flower-garden plant" he noted. Ornamental perilla is easy to grow in sun or light shade (Parke 1984) and its color is far more intense than the color of either wild or oilseed types. I have seen it grown as an attractive foliage screen behind shorter bedding plants. The purple foliage superficially resembles that of purple-leaved varieties of basil, Ocimum basilicum L.

Culinary

Perilla foliage "kkaennip namul" (Wade 1986) and seed oil (Choi et al. 1980) are used in Korean cooking. Korean markets in the United States sometimes sell perilla. An Oriental grocery in Ames, Iowa, sold bundles of fresh leaves for $6.53/kg in August, 1991. Perilla was an important vegetable in ancient China, but use in modern times has declined there (Li 1969). In Japan, the foliage of "shiso" serves as a garnish (Shurtleff and Aoyagi 1975). The foliage also provides a red (anthocyanin) food coloring; specialized red-leaved perilla varieties are used (Koezuka et al. 1985b) in the preparation of pickled plums (Ishikura 1981; Suyama et al. 1983; Chung et al. 1986). In addition to food coloring, perilla adds an antimicrobial substance to pickled foods (Kurita and Koike 1981). Perilla seeds are eaten in Japan (Ishikura 1981) and in parts of India (Standal et al. 1985).

Volatile Oil

In Japan, a volatile oil is distilled from the dried foliage of perilla (Guenther 1949; Nago et al. 1975). Oil of perilla is used as a flavoring agent, in which perilla aldehyde is the desirable flavoring compound (Guenther 1949; Arctander 1960). One of the aldehyde isomers is 2,000 times as sweet as sugar and four to eight times as sweet as saccharin; it is used as a tobacco sweetener (Guenther 1949). Perilla alcohol, prepared from perilla aldehyde, is used in fragrances, and has legal food status in the United States and Europe (Opdyke 1981). A perilla collection from Bangladesh is a potential commercial source of rosefuran (Misra and Husain 1987), a compound of interest in flavoring and perfumery (Ohloff and Demole 1987).

Recently, nine genotypes of perilla with different volatile oil chemistries have been crossed to allow study of the genetic control of biosynthetic pathways (Koezuka et al. 1986a; Nishizawa et al. 1989, 1990). Through this work a list of chemotypes has been developed, which show classical segregation patterns. One genotype lacks perilla aldehyde but has perilla ketone (Koezuka et al. 1986a).

Medicinal

Asian herbalists prescribe perilla for cough and lung afflictions, influenza prevention, restless fetus, seafood poisoning, incorrect energy balance, etc. (Publications and Information Directorate 1966; Hu-nan Chung i yao yen chui so. Ko wei hui 1977; Perry and Metzger 1980; Duke 1985).

Studies of perilla's volatile oil have revealed that distinct chemotypes of perilla have dramatically different biological effects (Koezuka et al. 1985a, 1986a,b,c). The perilla aldehyde chemotype is the source of Japanese "ao-shiso" (Arctander 1960), a medicine with an agreeable fragrance (Koezuka et al. 1986a). The perilla ketone chemotype is toxic and extremely effective as a laxative without causing diarrhea in laboratory mice (Koezuka et al. 1985a). The phenylpropanoid chemotype contains myristicin (Koezuka et al. 1986a,b), which is reported to have hallucinogenic properties (Seto and Keup 1969).

Laboratory rats had better learning ability when fed a perilla seed oil diet than with a safflower oil diet. The beneficial effect of perilla seed oil is attributable to its high a-linolenate content (Yamamoto et al. 1987).

GERMPLASM

Maintenance and Manipulation

Perilla plants are easily grown for seed. They self-pollinate without insect visits and yield well in greenhouses. The plants are most easily managed when they flower soon after planting and remain short. If planted too early, they can grow more than two meters tall in greenhouse pots. For plants 7 to 60 cm tall, seeds should be planted 30 or fewer days before the flowering date. This method allows 330 plants per square meter of greenhouse space. The minimal planting to harvest cycle is about 77 days, seeds reach maturity six weeks after the first flowering. Zeevaart (1969) used a similar schedule with controlled day length.

Koezuka et al. (1985b) emasculated perilla by removing the corolla with adhering anthers, then pollinated, and used a genetic marker (red hypocotyl) to confirm each successful cross.

The greatest difficulty in perilla germplasm maintenance is limited seed viability in storage. At room temperature, the seeds can die in less than a year, but lowered temperature or humidity improves storage life dramatically (Cho et al. 1986). At the North Central Regional Plant Introduction Station, germination percentages fell below 1% in seed lots maintained in cold dry storage for 23 years. Frequent germination monitoring and regeneration are essential for long-term maintenance.

Sources

Perilla cultivars can be purchased from at least 37 commercial suppliers (Facciola 1990). Twelve cultivars are mentioned in a recent publication from Korea (Cho et al. 1986). The many Asian cultivars are consistent with that continent's position as the center of origin of perilla.

The North Central Regional Plant Introduction Station in Ames, Iowa, maintains 17 accessions of perilla (Table 1) and distributes seeds to researchers free of charge. Plant Introduction Station holdings include long- and short-season oilseed types. Fuelleman and Burlison (1944) had success in Illinois with our short season germplasm.

CROP PROSPECTS IN THE UNITED STATES

Vegetable perilla has a market niche catering to people from Korea and other Asian countries. Seeds of the ornamental plants are available from United States seed companies, and use is likely to continue. Seed oil is now produced in Korea,and until new markets are found for the oil, production in the United States is unlikely. One possible new market is for use as an animal feed additive, building on the enhanced learning ability of rats on a perilla seed oil diet (Yamamoto et al. 1987). The artificial sweetener from the volatile oil (Guenther 1949) may be of value but might require an investigation of health risks before commercialization in the United States.

Perilla alcohol is a minor commercial fragrance ingredient in the United States and in Europe (Opdyke 1981). The use of perilla volatile oil as a source of rosefuran is a novel and exciting idea (Misra and Husain 1987).

REFERENCES

*Journal Paper No. J.-14769 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 1018.
Table 1. Perilla accessions and seed maturity dates in Ames, Iowa, at the North Central Regional Plant Introduction Station. The seed maturity date depends upon daylength, not planting date. These data are from plants at least four months old at maturity.

Accession Seed maturity Type Source
PI 248664 Sept.10 Oil seed India
PI 246665 Sept.7 Oil seed USA
PI 248666 Sept. 7 Oil seed USA
PI 248667 Sept. 10 Oil seed USA
PI 248668 Sept. 4 Oil seed USA
PI 248670 Sept. 7 Oil seed USA
PI 248671 Sept. 27 Oil seed USA
PI 481701 Nov. 20 Unknown Bhutan
PI 481703 Nov. 12 Oil seed Bhutan
PI 481704 Nov. 19 Unknown Bhutan
PI 481705 Nov. 26 Unknown Bhutan
PI 546459 Nov. 5 White seed Nepal
PI 546460 Oct. 31 White seed Nepal
PI 553074 Oct. 19 Unknown Thailand
PI 553078 --- Red foliage Japan
PI 557009 Nov. 26 Unknown Thailand
Ames 18336 --- Oil seed Korea

Last update April 17, 1997 aw