Ginger, Kalgan. Turmeric. Zedoaria –
All these plants have long been cultivated in the tropical rainforests of Southeast Asia on the mainland and on the islands, and are also bred in climate-relevant places in America and Africa.
All of them are perennial herbaceous plants with a complex root system. The leaves are alternate, vaginal, with an oblong-lanceolate plate and a central vein protruding from below. Flowers in a short apical spike in the axils of large green stipules. The flowers consist of an outer within the flower bed, three-toothed, short, cup-shaped and an inner one within the flower bed, corolla-shaped, tubular with a limb of three several irregular lobes. Stamens in 2 rows – 3 in each. The stamens of the outer circle are sterile, the middle stamen has turned into a decoratively colored petal-like large lip, the two lateral stamens are small sharp teeth. In the inner circle, two lateral stamens are also underdeveloped and turned into nectaries, and only one stamen bears ordinary dust grains with abundant pollen. The fruit, if it appears, – a triangular box. Usually reproduction is vegetative, by rhizomes.
The rhizomes of these plants are rich in essential oil and pungent in taste. They are used as a means of stimulating the digestive activity of the stomach: their tinctures are part of various gastric and appetizing drops and tonics; powders are also used. Ginger rhizomes are also used in the food industry, in confectionery and alcoholic beverage production.
1. Ginger – Zingiber officinale Roscoe – not found in the wild. India is the ancient center of the culture of this plant.
From a strongly branched horizontal rhizome, several above-ground stems grow. Leaf-bearing stems consist of leaves clasping each other with narrow sheaths; in the upper leaves, the sheaths reach a length of 1 m or more, the leaf blade is 18-20 cm long; lower leaves with short sheaths. Flowering stems are shorter (within 30 cm in height), with strongly shortened blades of vaginal leaves, at the top they bear a spike-shaped inflorescence with wide stipules, in the axils of which flowers sit. Depending on the cultivated variety, the color is different. There are flowers with a purple-brown or yellow corolla, the lip is light or almost black-violet with yellow specks.
The rhizomes (Rhizoma Zingiberis) are marketed corked white or unpeeled, gray with annular leaf scars. The shape of the rhizomes is very characteristic – they are branched, strongly flattened laterally. Burning taste, fragrant smell.
The rhizome contains essential oil in the amount of 1.5-3%, the main component of which is sesquiterpene-air-zingiberenes (up to 70%), which have a characteristic ginger smell. In addition, the essential oil contains bisabolene, borneol and farnesene. The pungent taste of the rhizome is due to the resinous part known as “gingerol”, which turned out to be a mixture of different gingerols.
2. Chinese galangal – found in the wild only on about. Hainan in China, where it has long been introduced into culture; it is also bred on neighboring islands and in India.
A plant with a longish horizontal cylindrical highly branched rhizome 1-2 cm thick, red-brown on the outside, with ringed light leaf scars, a few roots go down. The rhizome gives branching 1 stem, only 10-40 stems; some of them are flower-bearing, the rest bear only leaves. Leaves vaginal, narrowly lanceolate, 18-30 cm long, alternate. The flowers are collected in a short apical spike, white, with a short tube and 3 long lobes; the petal-shaped lip is white, with red stripes. The fruit is a box.
Harvested rhizomes (Rhizoma Galangae) are washed from zetilla, cut into pieces and dried. The pieces in the break are reddish-brown, the primary bark is much wider than the small central cylinder, fragrant, the taste is spicy, burning.
The raw material contains an essential oil (0.6-1%), consisting of sesquiterpenes and sesquiterpene alcohols, cineole and eugenol. The essential oil and the resin contained in the plant (within 5%) have a burning taste. There are tannins (within 7%) and flavonoids (flavonols) – kaempferol methyl ether, galangin, etc.
Sometimes the rhizome of the so-called large galangal is harvested by mistake – Rhizoma Galangae majus from the plant Alpinia galanga (L.) Swarz. The rhizome pieces are similar in shape and are also red-brown on the outside with light annular leaf scars, but they are much larger in diameter, white inside and less fragrant. This raw material is used in the alcoholic beverage industry.
3. Turmeric – Curcuma longa L.; syn. C. domestica Val. – the birthplace of turmeric, probably India, is not found anywhere else in the wild.
The root system is complex: a tuberous, almost rounded rhizome up to 4 cm in diameter, yellowish-gray, with annular scars from the leaves, gives the aerial part from the apical bud; several lateral buds develop into underground, relatively short (within 3-10 cm long and 0.5-1 cm in diameter) cylindrical shoots.
One of the cylindrical shoots lengthens and gives rise to a new tuberous rhizome from the apical bud, which further develops in the same way; in addition, numerous thin roots depart from the tuberous rhizome. Some of them swell at the end into small nodules; these nodules are not yellow. The aerial part consists of several oblong, on long vaginal petioles, basal leaves up to 1 m long. The peduncle (within 30 cm) is densely planted with green, lighter stipules at the top, in the axils of which flowers develop in the middle part of the peduncle. The flowers are tubular, with a three-lobed, slightly irregular limb, yellow, the lip is wide, yellow.
Dug out rhizomes are poured with boiling water before drying; as a result of gelatinization of starch, the rhizomes become very hard after drying and do not germinate during storage. After sorting the raw materials, pear-shaped or ovoid rhizomes (Curcuma rotunda) and pieces of cylindrical side shoots (Curcuma longa) are sold separately; later – the main commercial variety of turmeric.
Turmeric rhizomes (Rhizoma Curcumae) are yellowish-gray on the outside, golden yellow when broken. On the transverse section of the rhizome, a central cylinder with numerous scattered vascular bundles (without fibers) is visible. The endoderm is clearly visible, outside of it is the primary cortex, closed with a cork.
Turmeric contains essential oil (1.5-5%) and yellow pigments (2.5-4.5%); the main one is curcumin. The essential oil contains sesquiterpene ketones (60%), sesquiterpene – zingiberene (25%), borneol and other terpenoids.
Due to the burning taste and aroma inherent in the essential oil and curcumin, the powder of the rhizome is used as a spice and a means to enhance the activity of the stomach. In addition, it is used as a choleretic. In an animal experiment, the choleretic effect of curcumin has been proven.
4. Zedoaria – Curcuma zedoaria Roscoe – grows wild in the eastern Himalayas, but all products are harvested from plantations.
The root system is built similarly to that of Curcuma longa L. Round rhizomes, oblong branches and thin roots are formed, sometimes with swellings. Leaves (up to 40 cm long) basal, broadly lanceolate (up to 11 cm wide), on short petioles; red stripes stretch along the central vein. Peduncles (up to 30 cm long) form an ear, seated with stipules, in the axils of which flowers sit. The upper part of the ear consists of a bunch of purple elongated leaf-shaped stipules without flowers. The flowers are yellow within the flower bed, the lip is wide, dark yellow. The fruit is a straw-yellow box.
Only round rhizomes (Rhizoma Zedoariae) are subject to collection, swellings on thin roots do not have a burning taste. Round rhizomes within 4 cm in diameter, brownish-gray outside with annular leaf traces. The dug out rhizomes are washed, cut into transverse slices and dried. Inside the rhizomes are light gray. Under a magnifying glass, a very wide central cylinder is visible, delimited by a clearly visible endodermis from a very narrow primary cortex.
The rhizome contains 1-1.5% essential oil, consisting of sesquiterpene alcohols (50%), zingiberene (10%), camphene (4%), pinene, borneol, cineole (10%) and other terpenoids. In addition, there are resin (4%), starch (50%) and other substances.
The plant contains sesquiterpenes.
PLANTS CONTAINING SESQUITERPENE
Acyclic (aliphatic) sesquiterpenes are considered as unsaturated compounds with 4 double bonds, which can be represented as an open bicyclic compound. From hydrocarbons farnesene is known, from oxygen derivatives – alcohols farnesol and nerolidol.
Monocyclic sesquiterpenes have one closed hydroaromatic ring and 3 double bonds located in the ring and in the aliphatic chain. Of the hydrocarbons in essential oils, bisabolene and zingiberene are the most common.
Bicyclic sesquiterpenes have 2 hydroaromatic rings and 2 double bonds (one in each ring). There are compounds like cadinene and selinene.
Bicyclic sesquiterpenes also include a large group of specific compounds known as “azulenes”, which are based on the skeleton of a highly unsaturated compound with 5 double bonds. Azulenes differ in the arrangement of functional groups.
PLANTS CONTAINING ESSENTIAL OILS
Essential oils are natural aromatic substances that are highly volatile and cause the specific smell of plants. For this reason, also due to their “oily” consistency and “greasy” stain on paper, which soon disappears, they received such a peculiar name.
Essential oils are not individual substances. These are complex mixtures of organic substances, the composition and number of which are different for each type of essential oil plants and can serve as a chemotaxonomic feature. The main group of substances that make up the essential oils of many plants are terpenes (more precisely, monoterpenes) and seseviterpenes, i.e., substances with an isoprenoid structure. However, in the essential oils of a number of plants, aromatic compounds may predominate, as well as numerous substances of the aliphatic series. There are plants with sulfur and nitrogen compounds in essential oils.
Essential oils in plants are mostly in a free state. However, some plants contain them in the form of glycosides and are released during enzymatic cleavage. Essential oils are formed in all parts of plants, but quantitatively they accumulate in them traditionally unequally.
They can be in a plant organism in a diffuse diffuse state (ie, emulsified or dissolved in cells) or accumulate, localize in special anatomical and morphological formations that are easily detected under a microscope. These excretory formations can be exogenous and endogenous.
Exogenous formations develop in the epidermal tissue and are:
– glandular “spots” – small-drop accumulations of essential oils immediately under the cuticle of the epidermis;
– glandular hairs – cylindrical epidermal outgrowths, consisting of a unicellular or multicellular pedicle and a head with cells that secrete essential oil;
– glands – epidermal outgrowths that have received the most
the highest specialization in the extraction and accumulation of essential oils. They have a different structure and can serve as a systematic feature. For example, in yasnotkovye (labial) 8 excretory cells are arranged in a rosette on a short stalk; in aster (composite) glandular cells have a vertical arrangement – 2 in 4 rows, etc.
Endogenous formations develop in parenchymal tissues and are:
– secretory cells – single (for example, in the air parenchyma of calamus rhizome) or form layers of such cells (for example, in valerian roots);
– receptacles – rounded cavities formed in the mesophyll of the leaf, peel of citrus fruits, in the bark and wood of a number of plants and filled with essential oil;
– tubules and passages – strongly elongated excretory formations found in the fruits of umbellate, bark and wood of a number of plants.
Essential oils accumulate in plants in all possible quantities: from hundredths and thousandths of a percent (for example, in violet flowers – 0.004%) to 20% or more (for example, in flower buds of carnations – up to 23%).
Essential oils are obtained: 1) by steam distillation; 2) extraction with some extractants; 3) enfleurage; 4) mechanically.
Steam distillation is the most common method. It is carried out in installations consisting of a distillation still with a double jacket (in which steam circulates to protect the still from cooling), a condenser and a receiver. Steam is fed into the cube loaded with raw materials from below through a perforated coil, entraining the essential oil. A mixture of cooled vapors of water and essential oil enters the receiver, where the mixture separates and excess water is removed through a tube at the bottom of the receiver (if oil is lighter than water) or through a drain tube at the top (if oil is heavier than water).
The extraction of essential oils from raw materials is carried out with volatile organic solvents in Soxhlet-type apparatuses or in column apparatuses. Subsequently, the raw material is lifted by the screw from the bottom up, and the extractant enters towards it. After distillation of the solvent, the residue is either pure essential oil or its mixture with other extracted substances (resins, waxes, etc.); in the latter case, additional cleaning is required.
Enfleurage is based on the fact that essential oil from raw materials (mainly from flowers) is absorbed by sorbents (solid fats, activated carbon, etc.) in special frame installations.
The mechanical method is used to extract essential oils from citrus fruits by pressing or scraping.
Although essential oils are very common in the plant world, their role for the plant organism and the reasons for their formation have not yet been reliably established. It was assumed that essential oils serve to protect plants from diseases and pests, to attract the smell of insects, which contributes to the pollination of flowers, to protect plants from excessive heating during the day and hypothermia at night, etc. Currently, most scientists believe that essential oils (or rather, their components) are actively involved in the metabolic processes of plant organisms.
Essential oils find a wide and varied application for medicinal, cosmetic, food (spices) and other chains.
Essential oils are classified according to the substances that make up their bulk, or substances that determine their medicinal and industrial value. There are the following groups (and subgroups) of components of essential oils:
Monoterpenes (terpenes), including:
1. Acyclic terpenes.
2. Monocyclic terpenes.
3. Bicyclic terpenes.
Sesquiterpenes, including:
1. Acyclic sesquiterpenes.
2. Cyclic sesquiterpenes.
Aromatic and phenolic compounds.
Sulfur and nitrogen-containing compounds.
The listed compounds, especially terpenoids, in essential oils can occur in the form of numerous oxygen derivatives: alcohols, aldehydes, ketones, phenols, acids, esters, lactones, oxides, quinones. The number of terpenoids also increases due to the tendency of many of these compounds to various forms of isomerism (optical, geometric, etc.).