Perilla seeds, also known as shiso seeds or Su Zi in Pinyin, were first recorded as a Chinese herb in the “Compendium of Materia Medica”, a famous herbology book written by medical sage Li Shizhen in the Ming Dynasty. Purple perilla plant has been cultivated in China for nearly 2,000 years for the purposes of medicine, oil, spice, food, and so on. When used as medicine, all shiso leaves, stems, and fruits are the medicinal parts; when used as food, its young leaves can be eaten raw and cooked soup while stems can be pickled. Perilla is becoming a multipurpose plant with high nutritional value in recent years, thanks to its unique active substances and nutrients. However, this article is going to focus on the medicinal uses of perilla seed only.
What are perilla seeds?
Just as its name implies, it mainly refers to the ripe fruits or seeds of Perilla frutescens (L.) Britt, which is a plant in the mint family Lamiaceae. Perilla nankinensis (Lour.) Decne. is its synonym. It is native to in East Asia and traditionally there are two different varieties – P. frutescens var. crispa and P. frutescens var. frutescens. In China it is mainly produced in provinces of Jiangsu, Anhui, and Henan. It is usually harvested and then dried in the sun in autumn when the fruits are ripe. Medicinally the seed is often used smashed (ground), raw or slightly fried.
Its fruit is ovoid or spherical and in diameter of 0.6 to 2mm. Surface is gray-brown and with slightly raised dark purple mesh pattern and slightly sharp base with off-white punctate stem scar. Peel is thin, brittle, and easily crushed. Seeds are yellowish white; seed coat is membranous; cotyledons are 2, white, and rich in oil. If crushed, it emits aroma. And it tastes slightly acrid.
Perilla frutescens (L.) Britt seed contains protein 17% and oil 51.7%. And oil is rich in unsaturated fatty acids, linolenic acid 56.8%, and linoleic acid 17.6%; the seed of variety P. frutescens (L.) Britt. var. crispa contains 25.7% lipids, which include triacylglycerol 0% to 80%, diacylglycerol, monoacylglycerol, sterols, sterol esters, conjugated lipid acids, and free fatty acids.
Perilla seeds benefits
The whole shiso plant has a high nutritional value and is characterized as low sugar, high fiber, high carotene, and high mineral elements. More importantly, it also contains the active ingredient that is able to inhibit reactive oxygen and prevent aging. Its leaves are also rich in nutrition, in particular carotene and vitamin C, B2, which can help strengthen the body’s immune function. According studies, up to 106.2 micrograms of SODs (superoxide dismutase enzymes), a known antioxidant, is contained in per mg of perilla leaves. That’s to say, eating it on daily basis can defy aging. As a result, these days perilla plant has been grown on a large scale for commercial purpose in many countries, including Russia, Japan , South Korea, the United States, Canada, and the like. And dozens of perilla products, such as cooking oil, medicines, pickle, and cosmetics, have been developed.
In terms of perilla seed, it contains a lot of fat, and the oil yield can be up to about 45%. In addition, it also contains 25% protein, 18 kinds of amino acids, oryzanol, vitamin E, vitamin B1, sterol, phospholipids, and the like. And it contains more lysine and methionine than the high-protein plant grain amaranth.
Perilla oil is distilled from the whole pant while perilla seed oil is from its seeds. Long-term consumption of this oil can greatly help the treatment of coronary heart disease and high cholesterol. More than that, the World Health Organization has concluded its health benefits as follows:
1) Improve intelligence and brain fitness;
2) Resist aging;
3) Reduce cholesterol levels and lower blood lipids;
4) Reduces thrombus formation;
5) Inhibit tumor;
6) Improve the reflectivity of the retina and enhance vision;
7) Benefit a healthy pregnancy and a healthy baby. So, it is ideal for pregnant women, lactating women, and people with high cholesterol.
Modern pharmacological actions of shiso seed oil
1) It has a significant lipid-decreasing effect, which can prolong the survival rate and time of rats that are more likely to develop apoplexy due to spontaneously hypertensive;
2) It can improve the learning ability of experimental animals;
3) Experiments demonstrates that is has anticancer activities.
Sample perilla seeds recipes on herbal remedies
The Chinese Materia Medica believes that it is acrid in flavor and warm in nature. It goes to meridians of lung and large intestine. Essential functions are direct Qi downward, resolving phlegm, relieving asthma, and lubricating the intestines. Primary perilla seed uses and indications include phlegm obstruction, reversed flow of qi, cough, asthma, and constipation due to intestinal dryness. Recommended dosage is from 5 to 10 grams in decoction. Besides, it is also used in the forms of perilla seed tablets, powder, and pills.
1) San Zi Yang Qin Tang from Han Shi Yi Tong (Han’s understanding of medicine). It is matched with Bai Jie Zi (White Mustard Seed) and Lai Fu Zi (Radish Seeds) to treat obstructed phlegm and reversed flow of qi, cough, wheezing, excessive phlegm, and feeling of stuffiness in chest.
2) Su Zi Jiang Qi Tang from Tai Ping Hui Min He Ji Ju Fang (Formulas of the Peaceful Benevolent Dispensary). It is formulated with Rou Gui (Cinnamon Sticks), Dang Gui (Dong Quai), Hou Po (Magnolia Bark), etc. to cure chronic cough and asthma due to upper excess and lower deficiency.
3) Zi Su Ma Ren Zhou from Ji Sheng Fang (Life-saving prescriptions). It is combined with Xing Ren (Apricot Seed), Huo Ma Ren (Hemp Seeds), Gua Lou Ren (Semen Trichosanthis), etc. to heal intestinal dryness with constipation.
4) Su Zi San from Dian Nan Ben Cao (Pharmaceutical Natural History of Southern Yunnan). It is coupled with Apricot Seed to treat chronic cough in toddler accompanied with seesaw respirations. In addition, adding extra whitish honey can treat cough and recurrent wheezing in elderly people.
Clinical research of perilla seed
Clinically perilla seed based remedies can be used in the treatment of cough, asthma, constipation, allergies, intestinal ascariasis, hyperlipidemia, and more.
a) 100 cases of intestinal ascariasis have ever been treated by taking crushed or chewed fresh perilla seeds when the stomach was empty. And 92 cases discharged worms;
b) In a double-blind randomized controlled trial of perilla seed oil and Evening Primrose Oil capsules, 74 cases of patients with hyperlipidemia have been treated. The former was more effective on lowering cholesterol and triglycerides. And the result showed that perilla oil was for more preferred in the treatment of the hyperlipidemia type caused by yin deficiency and yang excess.
Perilla seeds side effects and contraindications
Perilla seeds fed to cow at the dose of 2.3 to 15.5g/kg can cause atypical interstitial pneumonia. However, after the frost period this herb has no such toxicity. According to Ben Cao Feng Yuan (The medicinal herbs in the wild), it controls conveyance and dispersion in nature and shouldn’t be used in chronic qi- deficiency cough, yin-deficiency asthma, and spleen-deficiency loose stool.
a) Si Chuan Zhong Yi (Sichuan Chinese Medicine), 1986; 8:47;
b) Liao Ning Zhong Yi Za Zhi (Liaoning Journal of Traditional Chinese Medicine) 1999; 3:135.