Aromatic waters, essential oils

Steam Distillation. Although in use for well over a century, steam distillation is still used In some essence plants. The raw aromatic substances are placed in a vessel with water. The steam produced carries the odorous substances and, when condensed, yields essential oil and scented waters. Most installations of this lype are found in the underdeveloped countries. 

Ishikawa et al. (2003) could obtain 33 compounds, including two new monoterpenoids, four new monoterpenoid glycosides, two new monoterpenoid glucoside sulphates and two new aromatic compound glycosides, from the water-soluble portion of the methanol extract of coriander fruit. Their structures were clarified by spectral investigation. The major constituents of coriander essential oils (dried fruits, herb prior to flowering and flowering herb) are listed below. 

A relatively simple apparatus was described by Lucchesi et al. (2004) for extracting essential oils from aromatic plant material by atmospheric solvent-free microwave extraction (SFME) without the addition of any solvent or water. The essential oils from spices like star anise extracted by SFME for 30 min and lh were similar to those obtained by conventional hydrodistillation (HD) for (respectively) 4 and 8 h. 

Is a water-soluble surfactant. It is useful as a foam builder and solubilizer for alkyl aryl sulfonates, essential oils, aromatic solvents, fats, and waxes. TRYCOL 5949 is also used as a co-emulsifier. 

The gasiroinie.slinal (Gl) aniispasmodic properties of bisaboloi and its oxides are well known. In fact, bisaboloi is said to be as potent as papaverine in tests of muscle spasticity. Besides bisaboloi. the flavone and coumarin components have -antispasmodic activities. The blue compound chamazulene posse.sses both anti-inflammatory and antiallcigenic ac-tivitic.s. as do the water-soluble components (the flavonoids). Apigenin and lutcolin possess anti-inflammatory potencies similar to that of indtimethacin. These flavonoids possess acidic phenolic groups, a. spacer, and an aromatic moiety that could fit into the COX receptor. None of the.se effects has been unequivocally documented in humans. The essential oil posse.s.ses low water. solubility, but teas used over a long period of time provide a cumulative medicinal effect. Typically. I teaspoon (3 g) of flower head is boiled in hot water for IS minutes. 4 times a day. 

Eucalyptus citriodora Hook f (Lemon gum) The oil of the fresh leaves of E. citriodora (2.2-8.3%), a tree introduced into Kenya from Australia (68), has been well researched in Kenya. Results indicate that there are two chemical varieties that were introduced. The chief essential oil constituents of one variety are citronellal (65-88%), citronellol (2-25%) and isopulegol (2-19%). In constrast, the second variety has as its major essential oil consitutents citronellol (32-52%), citronellal (38-59%) and 1,8-cineole (2-19%) (68,69). The essential oil is regarded as a perfumery oil. This plant is the second most commercially important Eucalyptus species in the essential oil trade and is only second to E. smithii Baker (69). The aromatic oil is used in soaps, creams and lotions due to its desirable odor properties, and as with many other essential oils is also used extensively in many technical preparations to mask other industrial malodors. A highly active mosquito repellent compound, p-menthane 3,8-diol has been isolated from the waste water of distillation of E. citriodora. There are now many commercial mosquito repellents based on this waste water (70-73). 

As outlined when discussing absorption bases, the drug may also be dissolved in water to form a solution to be levigated into an ointment base or cream. Such addition softens creams even to the point of converting them to thick lotions. The chosen vehicle, of course, must have an inherent capacity to emulsify or otherwise take up the solution. Aromatic materials such as essential oils, perfume oils, camphor, and menthol, which volatilize if added when the base is hot, are incorporated into these semisolids while they are stiU being mixed but near the temperature where a particular system starts to congeal. Volatile materials are often introduced into the formulation as hydroalcoholic solutions. 

One of the advantages of SEME is rapidity. The extraction temperature is the boiling point of water at atmospheric pressure (100 °C) for both SEME and HD extraction. Figure 22.4 shows the temperature profiles during SEME and HD of essential oil from aromatic herbs. To reach the extraction temperature (100 °C) and thus obtain the first essential oil droplet, it is necessary to heat for only 5 min with SEME compared with 90 min for HD. It is important to note that there is no superheating effect because of the heterogeneity of the medium and the available water used for SEME is provided from the plant matter moisture or the so called in situ water. 

The essential oils of fresh aromatic herbs (90% moisture) extracted by SEME for 30 min were quantitatively (yield) similar to those obtained by conventional hydrodistillation for 4.5 h. For extraction from dry spices, the plant material is soaked in water before extraction to achieve a maximum moisture content of 70%. Yields of essential oils obtained from spices by HD were higher than were obtained by SEME. 

The reduced cost of extraction is clearly advantageous for the proposed SFME method in terms of time and energy. Hydrodistillation required an extraction time of 90 min for heating of 6 L water and 500 g aromatic plants to the extraction temperature, followed by evaporation of the water and essential oil for 180 min. The SFME method required irradiation for 3 min only and evaporation for 27 min of the in-situ water and essential oil of the same material. The energy required to perform the extractions is 4.5 kW h for HD, and 0.25 kW h for SFME. The power consumption was determined with a Wattmeter at the microwave generator supply and the electrical heater power supply. 

Essential oils are classically extracted by Clevenger distillation [64]. This method proceeds by iterative distillation and boiling of the aromatic matrix by re-condensed vapors of water, and generally uses large quantities of water and energy. The extraction time can vary between 6 and 24 h. 

Aromatic plants are usually constituted from cellulose, essential oil, and water. If these three compounds are heated by microwaves at a fixed radiation power and for a set time, the heating rate will be the highest for water, followed by essential oil and cellulose, respectively. One of the interactions of the microwave energy with the matrix is called the dipolar polarization mechanism. A substance can generate heat when irradiated with microwaves if it has a dipole moment, for example that of the water molecule. A dipole is sensitive to external electric fields and will attempt to align itself with the field by rotation. 

The roots of distillation methods are attributed to Arabian Alchemists centuries with Avicenna (980-1037) describing the process of steam distillation, who is credited with inventing a coiled cooling pipe to prepare essential oils and aromatic waters. The rst description of distilling essen tial oils is generally attributed to the Spanish physician Arnaldus de Villa Nova (1235-1311) in the thirteenth century. However, in 1975, a perfectly preserved terracotta apparatus was found in the Indus Valley, which is dated to about 3000 BC and which is now displayed in a museum in Taxila, Pakistan. It looks like a primitive still and was presumable used to prepare aromatic waters. Further ndings indicate that distillation has also been practiced in ancient Turkey, Persia, and India as far back as 3000 BC. 

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