Plant Messengers-Advanced Aromatherapy
Essential oils play very important and diverse roles in plant metabolism. They serve to attract beneficial insects and defend against harmful organisms. Moreover, essential oils allow plants to send and receive signals and to communicate with one another.
It is probable that the simultaneous evolution of plants and plant-eaters led to the development of a chemical system of communication. Nutritional elements attracted plant-eaters of both sexes, resulting in the meeting of potential sexual partners at feeding places. Animals imitate the attracting plant signals by releasing similar scents, to attract a mate, for example. This is a simple communication system based on "borrowed" chemical messages.
Chemical communications require specific signals that can be clearly recognized and interpreted. They must be distinguish-able from "background scents" that are naturally present in the environment. Normally this is achieved through a unique, multifaceted mixture of less specified molecules. In nature, we often observe synergistic effects of multiple components in a "bouquet" of chemical messengers.
Nature prefers this solution to the complex synthesis of substances having specific, narrow functions. For example, the attracting pheromone for the bark beetle consists of an acetal and an ester. Pure acetal alone has very little activity, pure esters even less, but their combination is highly active. This specific acetal is not unique to the bark beetle. It has been identifies in the scents of various plants. The ester has been identifies in the secretions of another beetle and the scent of the Bartlett pear.
The effectiveness of chemical messengers hinges on another important factor , the symmetry of their molecular structure: organic molecules can consist of identical atoms but have different configurations in space. Two molecules -which are mirror images of each other (something like a right and left glove-are called enantiomers. Bark beetles, for example, use terpenes for chemical communications and create predominantly or exclusively one enantiomer.
Bark beetles, for example, use terpenes for chemical communication and create predominantly or exclusively one enantiomer. They are able to create an enantiomer ratio specific to their species which would lose its effectiveness if altered even slightly: it would no longer br recognized by other bark beetles.
One example from the plant world is the terpene alcohol a-bisabolol, which can be found in two enantiomeric forms, (+) a-bisabolol and (-) a-bisabolol. In the essential oil of German Chamomile mainly the effective (-) a-bisabolol is encountered. The chemical synthesis of a-bisabolol however, yields a 50:50 racemic mixture of (+) a-bisabolol and (-) a-bisabolol. Synthetic bisabolol, known as levomenol, is therefore not called bisabolol but racemic bisabolol.
It is interesting to note how much humans have been able to learn about insects, and how little of this knowledge we are willing to apply to the use of essential oils. Having examined how wonderfully precisely nature communications with the help of terpenes, and how the natural compositions guarantee uniqueness, we should realize that natural essential oils work more extensively and effectively than watered, down synthetic imitations from the kegs of the fragrance industry.
The reductionist style of treating essential oils as just another group of chemicals ignores the fact that not only beetles and plants have developed together, but also humans and plants. The interaction between humans and plants, and consequently between humans and natural essential oils, proved to be so successful and valuable that human cultivated specific plants, especially kitchen herbs, contributing to the survival of these species.
Analyses show that essential oils primarily consist of terpenes, terpene-related compounds, and phenylpropane derivates. We find among the terpenes all varieties of messengers, from sex attractants to highly effective defense signals. It helps to keep the information character of these aromatic molecules of the animal and plant world in mind as we look at the effects of essential oils on the healing process.
Reference: Advanced Aromatherapy-The Science of Essential Oil Therapy: Kurt Schnaubelt, Ph . D .
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