Perilla (plant)

This article is about the plant genus Perilla. For the single crop species, see Perilla frutescens. For herb and spice, see Perilla. For the Japanese variety and condiment, see shiso.
Perilla
Perilla frutescens var. acuta
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Lamiales
Family: Lamiaceae
Genus: Perilla
L.

Perilla is a genus consisting of one major Asiatic crop species P. frutescens and a few recognized wild species in nature, belonging to the mint family, Lamiaceae.

Until a few decades ago[1] , the oilseed crop for Perilla oil, from India, China and all across Eastern Asia was regarded as a species (P. ocymoides) in its own right, distinct from the "beefsteak plant" known for its red-leafed ornamental variety, although it was well established that these types readily cross-pollinate.[2] Recent genetic research confirm they are of a common gene pool,[3] corroborating the taxonomists' claim for consolidating the two crops into one species.

These past legacies and subsequent reclassification of taxa has led to a confusion of nomenclature.[4][5]

The red or purple leafed variety had been dubbed P. nankinensis,[6] and this label was used throughout the 19th century in the West when it was introduced as an ornamental. (See under #English common names).

Whether green-leafed or red-leafed, the perillaldehyde factor that characterizes the unique shiso fragrance may turn out to be present or absent in the individual or population, and this is not differentiable from outward appearance alone. Chemical studies classify the genus into different chemotypes, depending on the essential oils they contain.

There are three wild species endemic to Japan, recognized as being genetically distinct from the cultivated species.[7] But some references treat, e.g., P. citrodora as the same species as the cultivated one[8]

Selected species

Synonyms

(= P. frutescens unless noted otherwise)

Formerly placed here

Chemistry

The essential oil extracted from the leaves of perilla by steam distillation consists of a variety of chemical compounds, which may vary depending on species. The most abundant, comprising about 50–60% of the oil, is perillaldehyde which is most responsible for the aroma and taste of perilla. Other terpenes, such as limonene, caryophyllene, and farnesene, are common, as well.

Of the known chemotypes of perilla, PA (main component: perillaldehyde) is the only one used for culinary purposes. Other chemotypes are PK (perilla ketone), EK (eschscholzia ketone), PL (perillene), PP (phenylpropanoids: myristicin, dillapiole, elemicin), C (citral) and a type rich in rosefuran.

Perilla ketone is toxic to some animals. When cattle and horses consume purple mint (of the PK chemotype) while grazing in fields in which it grows, the perilla ketone causes pulmonary edema, leading to a condition sometimes called perilla mint toxicosis.

Perilla oil is obtained by pressing the seeds of perilla, which contain 35 to 45% oil. In parts of Asia, perilla oil used as an edible oil is valued more for its medicinal benefit than its flavor. Perilla oil is a very rich source of the omega-3 fatty acid alpha-linolenic acid. As a drying oil similar to tung oil or linseed oil, perilla oil has been used for paints, varnishes, linoleum, printing ink, lacquers, and for protective waterproof coatings on cloth. Perilla oil can also be used for fuel.

The oxime of perillaldehyde (perillartin) is used as an artificial sweetener in Japan, as it is about 2,000 times sweeter than sucrose.

References

Notes

  1. ↑ 佐竹, 義輔 (Yoshisuke Satake); 西, 貞夫 (Sadao Nishi); 本山, 荻舟 (Tekishū Motoyama) (1969) [1968], "しそ", 世界百科事典(Sekai hyakka jiten) (Heibonsha) 10, pp. 246–7 (world encyclopedia, in Japanese)
  2. ↑ e.g. 佐竹, 西 & 本山 1969 (Heibonsha encyclopedia), which classifies them as different species of the "same genus", and notes they hybridize easily
  3. ↑ Ito 2008, p.21, citing Ito et al., 1998
  4. ↑ Comprehensive study by Zeevart 1969 is often cited.
  5. ↑ See Yu, Kosuna & Haga 1997, p.2-3 for a sampling of this
  6. ↑ Yu, Kosuna & Haga 1997, p.2-3
  7. ↑ , "Ch. 2 Taxonomical Examination of Perilla Species and their revision – Studies on the Phylogenetic Relationship of the Species, p.20: "Japanese species 4 different species with 1 subspecies."
  8. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Blaschek, Hänsel & Keller 1998, Hagers Handbuch, vol.3, p.328
  9. 1 2 3 4 Bentham 1836,p.166
  10. ↑ Wiersema et al., "World Economic Plant: a standard reference (1999), p.160
  11. ↑ Rawayl & Pangtey, High Altitudes of the Himalaya: Biodiversity, ecology & environment (1994), p.338

Sources

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