Perilla, or shiso (also called beefsteak), is a popular vegetable in Asia that looks like a large-leafed basil. It’s seed oil is used in a variety of foods in Asia, as well, and so it has a long track record of safety in humans. In Asia it is also used as a traditional treatment for lung health and coughs, cold and flu. Perilla seed oil is high in omega-3 fatty acids, especially alpha-linolenic acid, and these have been well tested as anti-inflammatory compounds that are useful for a variety of inflammatory conditions. The omega-3 fatty acids are known to reduce a the production of many allergic mediators when supplemented to the diet. In addition to the essential fatty acids in Perilla, there are also several pharmacologically active phenolic compounds, such as rosmarinic acid, apigenin, luteolin, chrysoleriol, quercetin, and catechin (Ueda et al., 2002; Takeda et al., 2002; Nakazawa et al., 2003; Makino et al., 2003).
Few human studies yet exist on the therapeutic value of Perilla seed oil, but there are many on some of its chemical constituents, such as the omega-3 fatty acids, and rosmarinic acid. Due to its long use in foods, its interesting mixture of phenolic compounds, promising animal studies, and low cost, it may be an excellent alternative to fish oil supplementation.
Asthma and Allergies
Perilla seed oil, as a source of alpha-linolenic acid, was tested in asthma patients for the clinical features that accompanied leukotriene inhibition, including its effect on ventilatory parameters and lipid metabolism. The participants were divided into two groups. Group A were those who showed significantly suppressed leucocyte generation of leukotriene C4 (LTC4) by 4 weeks of Perilla seed supplementation. Group B were those who did not show leukotriene inhibition, but rather a significant increase in production after the same treatment. Analysis of the ventilatory clinical features and lipid metabolism between the groups prior to supplementation showed significant differences between groups, and these groups responded differently to Perilla seed oil supplementation. It was concluded that supplementation of Perilla seed oil is able to suppress generation of LTC4 in certain asthma patients, and that its ability to do so is related to clinical features such as respiratory function and lipid metabolism (Okamoto et al., 2000b).
Okamoto et al. (2000a) studied the effects of Perilla seed oil on bronchial asthma compared to the effects of corn oil on pulmonary function and the generation of leukotriene B4 (LTB4) and C4 (LTC4) by leucocytes. Perilla seed oil is rich in the omega-3 fatty acids, whereas corn oil is rich in omega-6 fatty acids. The groups were divided into 7 subjects each, and supplementation of the respective oil proceeded for 4 weeks. Significant differences in pulmonary function and leukotriene production were found between groups, and it was concluded that Perilla seed oil is beneficial for the treatment of asthma due to the suppression of LTB4 and LTC4 generation by leucocytes, and improvement in pulmonary function.
In a small study involving 5 asthma patients, supplementation with Perilla seed oil was reported to be helpful for asthma. After two weeks of supplementation, asthma symptoms, and morning and evening mean and peak flow rates (PFR) were improved significantly. Additionally, the generation of leukotrienes B-4 and C-4 by leukocytes were significantly reduced with supplementation (Kozo et al., 1997).
The effect of the long-term intake of an omega-3 fatty acid source, Perilla oil (PO), was compared to that of an omega-6 source, soybean oil (SO), on the risk factors of coronary heart disease and serum levels of fatty acids. Twenty elderly Japanese subjects were given SO for at least 6 months as a baseline period, then put on a PO diet for 10 months as the intervention period, and later returned to the SO diet as the washout period. The change in omega-6 to omega 3 ratio between the treatments, was 4:1 for the SO and 1:1 for the PO. At 3 months into the treatment period with PO, the alpha-linolenic acid in the serum increased from 0.8 to 1.6%, and the EPA and DHA increased from 2.5 to 3.6% and 5.3 to 6.4% respectively after 10 months of treatment, and returned to baseline in the washout period. The concentration of the oxidized LDL did not change significantly. It was concluded that in elderly subjects the levels of ALA, EPA and DHA could be increased significantly through dietary change without any adverse effects (Esaki et al., 1999).
In a study on the bioavailability of enteric-coated (Entrox) perilla seed oil, 12 healthy volunteers were given (enteric) coated or non-coated capsules containing 6 g of a Perilla seed formulation. The Perilla seed formulation was alpha-linolenic acid (ALA)-rich and was given in a single dose followed by a 3 week washout period. There were no difference in the pharmacokinetics of the two formulations, however, the levels of plasma ALA measured within 24 hours were significantly higher for the enteric-coated treatment group (Kurowska et al., 2003).
Safety / Dosage
Although Perilla has few clinical studies in humans, and most of the feeding studies have been done in animals, there has been a long track record of use in humans as a food in Asia, and this has never been associated with safety problems. About 6 grams daily of Perilla seed oil would contribute about 3 grams of alpha-linolenic acid to the diet.
Contact dermatitis develops in about 20-50% of the long-term workers with Perilla culture, and this is thought to be due to the 1-perillaldehyde and perillalcohol content of the shiso oil (Okazaki et al., 1981).
1.Ezaki O, Takahashi M, Shigematsu T, Shimamura K, Kimura J, Ezaki H, Gotoh T. Long-term effects of dietary alpha-linolenic acid from perilla oil on serum fatty acids composition and on the risk factors of coronary heart disease in Japanese elderly subjects. J Nutr Sci Vitaminol (Tokyo). 1999 Dec;45(6):759-72.
2.Kozo A., Fumihiro M, Takashi M, Yasuhiro H, Satoshi Y, Hirofumi T, Yoshiro T, Takao T. A pilot study: Effects of dietary supplementation with alpha-linolenic acid-enriched perilla seed oil on bronchial asthma. Allergology International. 1997 46(3):181-185.
3.Kurowska EM, Dresser GK, Deutsch L, Vachon D, Khalil W. Bioavailability of omega-3 essential fatty acids from Perilla seed oil. Prostaglandins Leukotrienes & Essential Fatty Acids. 2003 March;68(3):207-212.
4.Makino T, Furuta Y, Wakushima H, Fujii H, Saito K, Kano Y.Anti-allergic effect of Perilla frutescens and its active constituents.Phytother Res. 2003 Mar;17(3):240-3.
5.Nakazawa T, Yasuda T, Ueda J, Ohsawa K. Antidepressant-Like Effects of Apigenin and 2,4,5-Trimethoxycinnamic Acid from Perilla frutescens in the Forced Swimming Test. Biol Pharm Bull. 2003 Apr;26(4):474-80.
6.Okamoto M, Mitsunobu F, Ashida K, Mifune T, Hosaki Y, Tsugeno H, Harada S, Tanizaki Y, Kataoka M, Niiya K, Harada M. Effects of perilla seed oil supplementation on leukotriene generation by leucocytes in patients with asthma associated with lipometabolism. Int Arch Allergy Immunol. 2000a Jun;122(2):137-42.
7.Okamoto M, Mitsunobu F, Ashida K, Mifune T, Hosaki Y, Tsugeno H, Harada S, Tanizaki Y.Effects of dietary supplementation with n-3 fatty acids compared with n-6 fatty acids on bronchial asthma. Intern Med. 2000b Feb;39(2):107-11.
8.Okazaki N, Matunaka M, Kondo M, Okamoto K. Contact Dermatitis Due to Beefsteak Plant Perilla-frutescens-var-acuta. Hifu. 1982 24(2):250-256.
9.Takeda H, Tsuji M, Miyamoto J, Matsumiya T. Rosmarinic acid and caffeic acid reduce the defensive freezing behavior of mice exposed to conditioned fear stress. Psychopharmacology (Berl). 2002 Nov;164(2):233-5.
10.Ueda H, Yamazaki C, Yamazaki M.Luteolin as an anti-inflammatory and anti-allergic constituent of Perilla frutescens. Biol Pharm Bull. 2002 Sep;25(9):1197-202.
EDITOR'S NOTE: This monograph can be found in The Health Professional's Guide to Dietary Supplements (Lippincott, Williams & Wilkins) by Shawn M. Talbott, PhD and Kerry Hughes, MS.