Unlike synthetic chemicals, essential oil chemicals are diverse in their effects. No two oils are alike. Some constituents, such as aldehydes found in lavender and chamomile, are antimicrobial and calming. Eugenol, found in cinnamon and clove, is antiseptic and stimulatiing. Ketones, found in lavender, hyssop, and patchouli, stimulate cell regeneration and liquefy mucous. Phenols, found in oregano and thyme oil, are highly antimicrobial. Sesquiterpenes, predominant in vetiver, cedarwood, and sandalwood, are soothing to inflamed tissue and can also produce profound effects on emotions and hormonal balance. The complex chemistry of essential oils makes them ideal for killing and preventing the spread of bacteria, since microorganisms have a difficult time mutating in the presence of so many different antiseptic compounds. At the March 2000 International Symposium in Grasse, France, Dr. Berangere Arnal-Schnebelen presented a paper showing the antibacterial properties of essential oils against several infectious agents. Spanish oregano and cinnamon essential oils tested at above 95 percent efficiency against Candida albicans, E. coli, and a Streptococcus strain. This is significant as we face life-threatening, drug-resistant viruses and bacteria. Key Chemical Constituents in Essential Oils and Their Effects Constituent Representative Oil Effect Ketones Sage mucolytic Aldehydes Lemongrass calming Esters Lavender balancing Ethers Tarragon balancing Alcohols Ravensara toning Phenols Savory stimulant Terpenes Pine stimulant The essential oils of ravensara, melissa, oregano, mountain savory, clove, cumin, cistus, hyssop, and frankincense are highly antibacterial and contain immune supportive properties that have been documented by many researchers, such as Daniel Pénoël, MD and Pierre Franchomme. These oils are found in varying amounts in the immune support and antimicrobial essential blends.      Essential oils are chemically different from fatty oils (also known as fatty acids). In contrast to the simple linear carbon-hydrogen structure of fatty oils, essential oils have a far more complex ring structure and contain sulfur and nitrogen atoms that fatty oils do not have. The terpenoids found in many essential oils are actually constructed out of the same basic building block--a five-carbon molecule known as isoprene. When two isoprene units link together, they create a monoterpene; when three join, they create a sesquiterpene; and so on. Some of the largest molecules found in essential oils are triterpenoids, which consist of 30 carbon atoms or six isoprene units linked together. Carotenoids, which consist of 40 carbons or eight isoprene units, only occur in essential oils in tiny quantities because they are too heavy to be extracted via steam distillation. Diffentent molecules in an essential oil can exert different effects. For example, German chamomile (Matricaria recutita) contains azulene, a dark blue compound that has a powerful anti-inflammatory compounds. German Chamomile also contains bisobolol, a compound studied for its sedative and mood-balancing properties. There are other compounds in German chamomile that perform different functions, such as speeding up the regeneration process of tissue. Chemotypes A single species of plant can have several different chemotypes based on chemical composition. This means that basil (Ocimum basilicum) grown in one area might produce an essential oil with a completely different chemistry than a basil grown in another location. The plant's growing environment, such as soil pH and mineral content, can dramatically affect the plant's ultimate chemistry as well. Different chemotypes of basil are listed below: Ocimum basilicum CT linalol fenchol (Germany) —antiseptic Ocimum basilicum CT methyl chavicol (Reunion, Comoro, or Egypt) —anti-inflammatory Ociumum basilicum CT eugenol (Madagascar) —anti-inflammatory, pain-relieving Another species of plant that occurs in a variety of different chemotypes is rosemary (Rosmarinus officinalis). Rosmarinus officinalis CT camphor is obviously high in camphor. Camphor serves best as a general stimulant and works synergistically with other oils, such as pepper (Piper nigrum), and can be a powerful energy stimulant. Rosmarinus officinalis CT cineol is rich in 1,8 cineol, which is used in other countries for pulmonary congestion and to help with the elimination of toxins from the liver and kidneys. Rosmarinus officinalis CT verbenon is high in verbenon and is the most gentle of the rosemary chemotypes, It offers powerful regenerative properties and has outstanding benefits for skin care. Thyme (Thymus vulgaris) also has several different chemotypes. Some of theses are: Thymus vulgaris CT thymol is germicidal and anti-inflammatory. Thymus vulgaris CT linalool is anti-infectious.     Understanding Essential Oil Chemistry   Basic Chemical Structure The aromatic constituents of essential oils (i.e. terpenes, monoterpenes, phenols, aldehydes, etc.) are constructed from long chains of carbon and hydrogen atoms, which have a predomintly ring-like chemical structure.  Links of carbon atoms from the backbone of these chains, with oxygen, hydrogen, nitrogen, sulfur, and other carbon atoms attached at various points of the chain. Eugenol An aromatic molecule found in several essential oils including clove.  Clove oil has been used as an antiseptic for many years.   Reference: Essential Oils Integrative Medical Guide by D. Gary Young, N.D.