Phytoncides are antimicrobial allelochemic volatile organic compounds
derived from plants.
"The word, which means "exterminated by the plant",
was coined in 1937 by Dr. Boris P. Tokin ((1900-1984), a Russian biochemist from
Leningrad University. He found that some plants give off very active
substances which prevent them from rotting or being eaten by some insects and animals."
The Merriam-webster.com definition of Phytoncide: "any of various bactericidal substances obtained from plants (as onion and garlic)"
"Various spices, onion, garlic, oak and pine
trees (and bark) and many other plants give off phytoncides. The major ingredient
of Phytoncide is very volatile terpene with a number of other ingredients
Many scholars think that the emergence of SARS that caused the world trembled has deep relationship with the destruction of the forests in the Kuangdong area of China. The air in the place where there is no forest and tree is no longer living air. The destruction of forest means the lose of Phytoncide. Phytoncide controls or kills various germs and viruses in air, purifies the air and enhances the self-cleaning capability. Phytoncide has been keeping the health of mankind in invisible places. As the respiratory diseases and mutant virus have become worldwide issue, and various syndromes caused by the chemical substances become more serious problems in reality, the interests on Phytoncide will be magnified even more.
More than 5000 volatile substances defend the surrounding plants from bacteria, fungi and insects. Phytoncides work by preventing the growth of the attacking organism. These facts explain partially why feral bees that live in forest are healthy!
The idea of walking in the woods has been developed in Europe in the mid-nineteenth as a certain part of recreational activity. In Taiwan, South Korea and Japan, people commonly engage in so-called forest(or woods) bathing to breathe in phytoncides emitted by plant and trees, in order to improve their health. The physiological effects of phytoncide have been investigated in biometeorological research (Japanese Society of Biometeorology, 1992)."
"... Many of phytoncides possess the ability to destroy microorganisms, including ones that are pathogenic. Certain phytoncides kill microbic agents of disease in animals."
Page 255, Medical Geology By Miomir M.Komatina
Forest bathing enhances human natural killer activity and expression of anti-cancer proteins.
"In order to explore the effect of forest bathing on human immune function, we investigated natural killer (NK) activity; the number of NK cells, and perforin, granzymes and granulysin-expression in peripheral blood lymphocytes (PBL) during a visit to forest fields. Twelve healthy male subjects, age 37-55 years, were selected with informed consent from three large companies in Tokyo, Japan. The subjects experienced a three-day/two-night trip in three different forest fields. On the first day, subjects walked for two hours in the afternoon in a forest field; and on the second day, they walked for two hours in the morning and afternoon, respectively, in two different forest fields. Blood was sampled on the second and third days, and NK activity; proportions of NK, T cells, granulysin, perforin, and granzymes A/B-expressing cells in PBL were measured. Similar measurements were made before the trip on a normal working day as the control. Almost all of the subjects (11/12) showed higher NK activity after the trip (about 50 percent increased) compared with before. There are significant differences both before and after the trip and between days 1 and 2 in NK activity. The forest bathing trip also significantly increased the numbers of NK, perforin, granulysin, and granzymes A/B-expressing cells. Taken together, these findings indicate that a forest bathing trip can increase NK activity, and that this effect at least partially mediated by increasing the number of NK cells and by the induction of intracellular anti-cancer proteins."
From: International journal of immunopathology and pharmacology 20 (2 Suppl 2):3-8, 2007
A forest bathing trip increases human natural killer activity and expression of anti-cancer proteins in female subjects.
"We previously reported that forest bathing trips enhanced human NK activity, number of NK cells, and intracellular anti-cancer proteins in lymphocytes, and that the increased NK activity lasted for more than 7 days after the trip in male subjects. In the present study, we investigated the effect of forest bathing trip on human NK activity in female subjects. Thirteen healthy nurses, age 25-43 years, professional career 4-18 years, were selected with informed consent. The subjects experienced a three-day/two-night trip to forest fields. On day 1, the subjects walked for two hours in the afternoon in a forest field; on day 2, they walked for two hours each in the morning and afternoon in two different forest fields; and on day 3, the subjects finished the trip and returned to Tokyo after drawing blood and completing a questionnaire. Blood and urine were sampled on the second and third days during the trip, and on days 7 and 30 after the trip. NK activity, numbers of NK and T cells, and granulysin, perforin, and granzymes A/B-expressing lymphocytes in the blood samples, the concentrations of estradiol and progesterone in serum, and the concentrations of adrenaline and noradrenaline in urine were measured. Similar control measurements were made before the trip on a normal working day. The concentrations of phytoncides in the forests were measured. The forest bathing trip significantly increased NK activity and the numbers of NK, perforin, granulysin, and granzymes A/B-expressing cells and significantly decreased the percentage of T cells, and the concentrations of adrenaline and noradrenaline in urine. The increased NK activity lasted for more than 7 days after the trip. Phytoncides, such as alpha-pinene and beta-pinene were detected in forest air. These findings indicate that a forest bathing trip also increased NK activity, number of NK cells, and levels of intracellular anti-cancer proteins in female subjects, and that this effect lasted at least 7 days after the trip. Phytoncides released from trees and decreased stress hormone levels may partially contribute to the increased NK activity."
From: Journal of biological regulators and homeostatic agents 22(1) :45-55, 2008
Report by National Chung Hsing University Reveals the Secrets of Phytoncides
"Many people know that it is good for your health to walk in a forest and be exposed to the phytoncides they give off. However, most people have no knowledge of the constituents of these phytoncides. Associate Professor David Wang of the Department of Forestry and Associate Professor Jiunn-wang Liao of the Graduate Institute of Veterinary Pathology, National Chung Hsing University, have published Taiwan's first report on the constituents of phytoncides. The research confirms that the limonene phytoncide promotes sleep, and helps fight anxiety and ease pain. Due to the absence of an adequate collection technique, there has been no academic report on phytoncides in Taiwan and few research projects have been conducted overseas. Under the auspices of the Forestry Bureau, Prof. Wang spent four years shuttling between the university's Black Forest and the Hui-Sun Forest Station, Aowanda's Sweet Gum Forest, and Hsitou's Cryptomeria japonica Forest, collecting air samples using solid-phase microextraction, synthetic resin and portable pumps. After phytoncides are extracted from the air samples, they are isolated and analyzed using a gas chromatography-mass spectrophotometer (GC-MS). The researchers found that the constituents of phytoncides are similar to those of distilled Cryptomeria japonica essential oil. "Phyton" means "plant" in Latin, and "cide" is the natural substance (collectively referred to as a compound) that a plant gives off to kill microorganisms. In fact, phytoncides do not only exist in forests. They can be found in vegetables and fruit as well. After the constituents of phytoncides were identified, experiments were conducted on animals using Cryptomeria japonica essential oil. After being given Cryptomeria japonica essential oil, the rats were put to sleep through pharmaceutical means and it was found that Cryptomeria japonica essential oil improved their sleep quality. In addition, the researchers used an elevated plus maze to measure the impact phytoncide had on the rats. They discovered that a higher percentage of rats entered the open area and those that did stayed there for longer periods of time. Moreover, phytoncide was found to have a pain amelioration effect. Scientific data were utilized to prove that the Cryptomeria japonica essential oil in the phytoncides contains limonene, a key terpene constituent, that influences the central nervous system to a large extent, improves sleep quality, and helps fight anxiety and ease pain. The experiments also reveal that even given extremely high doses of Cryptomeria japonica essential oil, the rats demonstrated no toxic reaction, indicating that Cryptomeria japonica essential oil is safe to use. Prof. Wang notes that the phytoncide concentration in a Cryptomeria japonica forest varies as the temperature changes. The concentration peaks at a temperature of around 30 degrees Celsius, and it is higher in the summer than in the winter. Since Cryptomeria japonica essential oil and phytoncides share similar constituents, people who rarely visit Cryptomeria japonica forests may use Cryptomeria japonica essential oil in their bathrooms in place of phytoncides." From: http://english.moe.gov.tw/ct.asp?xItem=10743&ctNode=11020&mp=1
Experimental study of the effect of garlic phytoncides on dysenteric bacteria
"All 123 of the dysentery bacteria cultures tested were found to be sensitive to garlic phytoncides (I). Culture growth in bouillon was arrested by garlic juice when diluted to 1: 400-1: 80. The greatest sensitivity to I was evidenced by the Grigoryev-Shiga dysentery bacillus. No difference was noted in the sensitivities of freshly cultured and museum strains. Culture in a medium containing I did not increase the resistance of the cultures. Continued cultivation in media containing I brought about modifications in the morphological properties of dysentery cultures (large numbers of long filamentous and coccus-type forms appeared, R-colonies predominated), but biochemical properties and agglutinability remained the same. I is not toxic for white mice. The activity of I decreased by 2 times in one month and by 4 to 10 times in 3 months.