MEDICINAL PLANTS - O.O. Annamuhammedova - 2014

I. Theoretical Part

Topic: Medicinal Plant Raw Material. Rules for Harvesting, Drying, and Storing Medicinal Raw Materials

Objective: to understand The concepts of medicinal raw Materials, medicines, and dosage forms, as well as the fundamental rules for harvesting and storing medicinal raw materials.

Outline

1. Types of medicinal plant raw material.

2. Concepts of medicines and dosage forms.

3. Rules for harvesting, drying, and storing medicinal raw materials.

4. Variability in the Chemical composition of Medicinal Plants.

5. Standardizing raw materials to meet quality requirements.

6. Packaging, labeling, and transportation of MRM.

Key terms and concepts of the topic: medicinal plant raw material, BIOLOGICALLY ACTIVE SUBSTANCES (BAS), active ingredients, accompanying substances, medicines, officinal raw material, diagnostic features, identity, quality, dosage form, drying, shade-air drying, sun drying, convective drying, packaging, labeling, transportation.

Questions for independent study:

1. Explain the difference between galenical and neo-galenical preparations.

2. What substances are referred to as ballast substances? What is their role in medicinal raw materials?

3. What biological characteristics determine the rules for harvesting specific parts of plants as medicinal raw materials?

4. Features of drying medicinal raw materials with artificial heating.

5. Features of drying medicinal raw materials under vacuum.

6. Features of drying medicinal raw materials in a liquid nitrogen environment.

QUESTIONS FOR SELF-analysis and self-assessment:

1. List the types of medicinal plant raw material.

2. What are the Specific features of harvesting all types of medicinal raw materials?

4. What determines the specific harvesting period for medicinal plants?

5. Rules for harvesting various Organs of medicinal plants.

6. What Methods of drying medicinal raw materials are known to you?

7. How is the storage of medicinal plant raw materials carried out?

1. Medicinal plant raw materials are whole medicinal plants or their parts used in dried (sometimes fresh) form to obtain medicinal substances, herbal medicines (phytopharmaceuticals), and their dosage forms.

Each type of medicinal raw material has a Latin name under which it is described in the national pharmacopoeia, standards, and technical specifications, and is prescribed by doctors. These names consist of two words. The first is the name of the plant organ or product obtained from natural sources, and the second is the name of the plant genus that supplies this raw material (for example, sunflower oil — Oleum Helianthi).

Biologically active substances (BAS) are substances that affect biological processes in the animal and human body.

Active substances are biologically active substances that can alter the state and Functions of the Organism or exhibit prophylactic, diagnostic, or therapeutic effects, and are used in The production of finished medicinal products.

Concomitant substances is a conventional term for metabolic products found in medicinal plants alongside biologically active substances. They can affect the body positively or negatively, influence the absorption of main biologically active substances by increasing their efficacy, prolonging their action, etc.

2. Medicines are substances or mixtures of substances of natural, synthetic, or biotechnological origin used to alter the physiological state of the body, for Prevention, Diagnosis, and Treatment.

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Medicines derived from PLANT AND ANIMAL raw materials can be divided into the following groups:

· Medicinal raw materials dispensed in the form of powders, teas, and herbal mixtures;

· Galenical and neo-galenical preparations — alcoholic extracts from plants in the form of tinctures and extracts; neo-galenical preparations are extracts purified from concomitant substances;

· Products of primary plant Processing — essential and fatty oils, Gums, resins, etc.;

· Individual active substances — Alkaloids, Glycosides, essential oil components, etc.

Dosage form is a medicinal product given a state convenient for application and achievement of the necessary therapeutic effect.

Dosage forms made from plant and animal raw materials intended for external, internal, and injection use: herbal mixtures, teas, infusions, tinctures, extracts, decoctions, ointments, drops, aerosols, tablets, capsules, pastes, granules, suppositories, microcapsules, powdered herbal raw materials, Suspensions, solutions for injection, and solutions for inhalation.

3. More than 20,000 species of lower and higher plants grow in our territory, of which 2,500 possess medicinal properties. Official medicine utilizes about 240 species. Biologically active substances accumulate in various PARTS OF THE plant organism during specific periods of their development. In some plant species, medicinal substances accumulate in buds, leaves, and stems, in others in flowers or fruits, and in still others in roots or bark; moreover, their quantity does not remain constant during various Phases of plant vegetation and sometimes fluctuates even throughout the day. In this regard, usually only those plant parts that contain the highest amount of therapeutic substances are harvested. Untimely harvesting may result in gathering plants with the lowest content of active compounds, rendering their value negligible. The time and place of accumulation of biologically active substances in a plant essentially determine the timeframe for its harvesting.

The quality and safety of medicinal plant raw materials largely depend on adherence to harvesting schedules, optimal harvesting technology, and drying conditions. During harvesting, it is necessary to consider the biological characteristics of medicinal plants, the dynamics of BAS accumulation, and The impact of harvesting on the condition of the thickets.

The purpose of primary processing is to eliminate harvesting shortcomings, remove impurities and defective plant parts, and prepare the raw material for drying. Purity of collection is one of the fundamental requirements of harvesting.

Collection must be carried out carefully, avoiding the inclusion of foreign impurities and other parts of the same plant in the harvested material. The presence of impurities reduces the quality of the raw material and sometimes makes it completely unsuitable, as subsequent sorting is often difficult and too expensive. Plants that are heavily dusty or contaminated in any way, growing near highways and railways, or damaged by insects, rust, or fungal diseases should not be harvested.

Each type of raw material has its own calendar periods and harvesting characteristics. It has been experimentally proven that in the aerial parts of the plant, the content of biologically active substances reaches its maximum during the flowering period and at the beginning of fruiting; in fruits, during the period of full ripeness; in roots, after the die-back of the plant's aerial part; and in bark, during the spring sap flow period.

Buds (Gemmae). Birch, poplar, and pine buds are used as medicinal raw materials. They are harvested in early spring when they swell but have not yet started to grow; this typically occurs in March–April. Large buds (pine) are cut with a knife, while small ones (birch) are threshed after drying. Buds must be dried very carefully: for a prolonged period in a cool, ventilated room, because in a warm room they begin to open.

Bark (Cortex) of trees and shrubs, such as oak, guelder-rose, and buckthorn, should be harvested in spring during the period of intensive sap flow. At this time, it easily separates from the wood. Later, in late spring and summer, when growth stops, the bark cannot be stripped. To remove bark from young felled or cut branches, circular incisions are made with a sharp knife at a distance of 25–50 cm from each other, connected by one or two longitudinal incisions, and then peeled off in the form of troughs or tubes. If the bark is covered with growths of bushy Lichens, they must be thoroughly cleaned with a knife beforehand; otherwise, the raw material may be spoiled without yielding full-value medicine.

For medical purposes, it is advisable to harvest bark in winter or spring from trees and shrubs in areas designated for felling in the current year, or during logging operations.

Leaves (Folia) are harvested before or during plant flowering, when no more than 25% of the flowers have transitioned to mass flowering. This is done in dry weather by plucking the leaves by hand. Usually, only developed basal, lower, and middle stem leaves are collected. Withered leaves, and especially those eaten by insects or damaged by Fungi, must not be harvested — they will not yield quality medicine.

"Herb" (Herba) (medicinal raw material in the form of flowering shoots together with leaves of herbaceous plants) is harvested during flowering (prior to fruiting) without rigid stem parts. Pulling plants out by the roots is not permitted. The "herb" of annuals is harvested before fruiting without coarse plant parts. At least 20% of the plants must be left within the harvesting area for seed regeneration.

They are harvested using sickles, knives, or pruners, avoiding the coarse parts near the ground. Sometimes, in areas with dense vegetation, plants are mown with scythes or sickles, and then gathered from the cut grass.

Flowers (Flores) are harvested According to the blooming period of each plant species during peak mass flowering, preferably before they begin to fade. At least 20% of the strongest mature specimens must be left behind in the area to ensure subsequent seed regeneration. During this phase, flowers contain the highest concentration of active ingredients, shed less during storage, withstand drying better, and retain their color. Flowers are picked by hand by plucking them and breaking off the pedicels. Occasionally, special collection tools such as combs or strippers are used. For instance, combed strippers are employed to gather chamomile flower heads.

Fruits (Fructus) and seeds (Semina) are usually gathered just before they reach full maturity. Fruits are plucked by hand (without pedicels) in the morning or evening, as those harvested in the heat spoil faster. In rowan, caraway, and other plants where fruits grow in umbels or corymbs, they are harvested and processed as whole clusters, which are then carefully separated from the pedicels after drying. Rose hips should be harvested along with the calyx remnants remaining at the top of the fruit. These remnants are removed after drying by rubbing the fruits between the hands. Harvesting succulent fruits—such as blueberries, raspberries, and strawberries—is particularly challenging. When placing them in baskets, each layer should be interspersed with twigs to prevent the fruits from packing down and bruising. Damaged or spoiled fruits must be discarded. It is best to collect fruits into baskets lined with burlap on the inside. For plants whose fruit takes the form of a capsule or pod, seeds are gathered right before they split open. Freed from dust and impurities, the seeds are air-dried slightly to prevent mold.

Roots (Radices), rhizomes (Rhezomata), bulbs (Bulbi), and tubers (Tubera) are typically harvested during the dieback of above-ground parts when plants enter a period of dormancy (late summer to autumn), after the seeds have shed, or in early spring when active compounds accumulate within them. Harvesting is planned based on the permissible annual yield calculated for a specific species, or by selecting the strongest specimens, not exceeding 10% of the plants in a given area. This raw material can also be gathered in early spring before the above-ground organs begin to sprout, though the harvesting window then is extremely short (just a few days). They are dug up with spades, or sometimes pulled from loose soil using pitchforks or rakes. The soil is excavated in a 10-15 cm radius around the stem, sinking the spade deep enough to avoid cutting the roots, after which they are turned out of the ground. Rhizomes and roots are first shaken free of soil and then thoroughly washed in Water. For larger-scale harvesting, washing is best done in large woven baskets immersed in running water. Once washed, the roots are immediately spread out on mats, clean grass, burlap, or paper to dry. Afterward, the roots and rhizomes are cleaned of stem remnants, small rootlets, and damaged or decayed parts before being transported to the final drying Location.

Medicinal plants are best harvested on dry, sunny days after the dew has evaporated, as damp plants dry slowly and are prone to mold growth. High humidity activates Enzymes and neutralizes active components. Raw material collected while wet darkens rapidly during drying and loses its quality. Dusty plants growing alongside roads, as well as those damaged by pests or diseases, should be avoided. As soon as possible after harvesting, the plant material is dried in a well-ventilated area under a canopy. To ensure proper drying, the material should be laid out in a thin layer and turned over periodically. Essential oil-bearing plants are laid out in a thick layer and dried at temperatures not exceeding 25-30 °C, whereas those containing alkaloids and glycosides are dried at 50-60 °C. The optimal drying Temperature for succulent fruits is 80-90 °C, and for roots and rhizomes, 40-50 °C.

High-quality plant material is considered to be that which retains its natural appearance, color, and scent after drying. When it absorbs moisture, it Molds, spoils, and loses its specific aroma and medicinal properties.

Proper storage and harvesting of medicinal raw materials ensure that the pharmacological potency of the active substances is preserved or even enhanced.

Most raw materials are stored in baskets, crates, or bags. Essential oil-containing plants must be stored separately from others in airtight wooden boxes lined with white tinplate. Stored in a well-ventilated, dry, and cool room, medicinal plant materials can last for several years. The shelf life of different plant parts varies. Leaves and flowers can be kept for 1–2 years, though preferably no longer than a year. Bark, rhizomes, tubers, and roots retain their medicinal properties for 3–4 years, while buds last for about 2 years.

The shelf life of medicinal raw materials is determined by State Standards and the State Pharmacopoeia.

When harvesting medicinal raw materials, one must handle plants with care, avoiding their complete depletion either in specific areas or across entire regions.

4. The chemical composition of plants is characterized by variability—The ability to acquire new chemical traits or lose previous ones under METABOLISM/18.html">The Influence of various factors. Genotypic (hereditary), phenotypic (non-hereditary), individual, and group variability are distinguished.

Genotypic variability includes changes in a plant's chemical composition caused by alterations in its genotype. Metabolic variability has been proven even within a single species, driven by the organism's hereditary foundation and the conditions under which ontogeny takes place. Variability in chemical composition is frequently observed in essential oil-bearing plants and typically affects their primary constituents.

The formation and accumulation of biologically active substances in medicinal plants is a dynamic process linked to developmental stages and environmental factors. The dynamics of active ingredient synthesis in each plant follow specific patterns, are subject to ontogenetic laws, and depend on plant age and the phase of vegetation. This is crucial to know for determining the optimal harvesting times for raw materials. For instance, when harvesting opium poppy, all of its characteristic alkaloids appear immediately after seed germination, except for morphine, which appears In the second month. Alkaloid levels peak during the flowering phase, subsequently decline, and disappear entirely before the frosts.

Ontogenetic traits include the Specificity of the qualitative composition of pharmacologically active substances within systematic plant divisions (species, genera, families, classes). Certain plant groups predominantly accumulate cardiac glycosides, while others accumulate anthracene derivatives, and so on.

A notable characteristic of plants is the uneven distribution of active substances across organs and Tissues, with a preferential localization in specific morphological structures. For example, in plants of the Apiaceae family, Essential Oils accumulate in the fruits.

An even wider spectrum of chemical variability is observed in medicinal plants under the Influence of Environmental factors (growing conditions), specifically:

1. Plant metabolism largely depends on soil composition, the presence of mineral nutrients, moisture levels, microflora, mechanical Structure, and soil warming.

2. Precipitation and air humidity affect the Qualitative and quantitative composition of chemical substances in the plant. Excessive moisture is detrimental to xerophytes, whereas arid growing conditions are harmful to hygrophytes. Mesophytes occupy an intermediate position, as they

3. Thermal and light energy dictate the duration of the growing season, the accumulation of active substances, and the biomass of the raw material. Each plant has an upper temperature threshold that enables it to complete its life cycle fully. Thermal regime considerations form The basis of medicinal plant cultivation at zonal research stations. For instance, *Anabasis aphylla* (or Richter's saltwort), when growing in the desert, contains only trace amounts of alkaloids, whereas cultivated specimens grown with strict adherence to agricultural practices yield over 1.5%. Warm weather promotes higher alkaloid content in plants, cold weather inhibits their synthesis, and frosts prevent alkaloid accumulation.

4. The impact of Nutrition, light, heat, and moisture on the metabolism of medicinal plants is essentially the influence of geographic factors, which encompass a complex of ecological conditions related to geographic features such as latitude, longitude, exposure, and altitude above sea level. Plants in southern latitudes generally accumulate higher concentrations of active substances. One need only point to the potency of poisonous plants in tropical countries. Geographic longitude is also highly significant: plants from eastern, more continental Regions of the European mainland yield higher quantities of essential oils. It is well established that in oil-bearing plants, fatty acid content and the iodine value of the oils increase the further they are grown from the coast into the interior of the continent.

Drying is a method of plant preservation through optimal dehydration. Freshly harvested medicinal raw materials typically contain 85–90% moisture, whereas dried materials contain 8–15%.

Biochemical processes in harvested raw materials initially proceed as they would in a living plant, meaning the synthesis of biologically active substances predominates. Later, as the supply of moisture and nutrients ceases, The breakdown of these active compounds begins, leading to a decrease in their concentration within the material. However, in certain cases, these processes actually increase the content of active ingredients. For instance, an accumulation of Essential oils and cardiac glycosides has been noted during slow drying (as seen in valerian and foxglove).

General rules for drying:

- raw materials containing essential oils are dried at 30–45 °C, spread in a layer 10–15 cm thick to prevent evaporation;

- raw materials containing glycosides are dried at 50–60 °C, which rapidly inactivates the enzymes that destroy glycosides;

- for raw materials containing alkaloids, the optimum temperature is up to 50 °C;

- raw materials rich in ascorbic acid are dried rapidly at 80-90 °C.

Experimental studies have estimated the weight loss of raw materials upon drying: buds — 65-70%, flowers and flower buds — 70-80%, leaves — 55-90%, herbs — 65-90%, roots and rhizomes — 60-80%, bark — 50-70%, fruits — 30-60%, and seeds — 20-40%.

Methods of drying medicinal plants are divided into two main groups: drying using natural heat without artificial heating (shade-drying in the air, sun-drying); drying with artificial heating (thermal drying); vacuum drying; and drying in a liquid nitrogen environment.

Shade-drying is carried out under shelters, in adapted attics (preferably under an iron roof), or in specially equipped rooms. The key requirements are maximum exposure to solar warmth and good ventilation. Drying areas are usually equipped with racks covered with fabric or wire mesh. The raw materials are spread in a thin layer on frames; the upper shelves are used for materials that require rapid drying (such as lily of the valley flowers, pheasant's eye herb, and glycoside-containing raw materials). Essential oil-bearing and other materials that require low temperatures for drying are placed on the lower shelves, arranged in such a way that their aroma does not spread to other species.

Sun-drying, which utilizes the heat of solar radiation, is the simplest, most economical, and most accessible method.

However, this destroys chlorophyll, causing leaves to turn brown and altering the color of many flowers. Although these changes do not always involve the degradation of active compounds, the commercial appearance of the raw material deteriorates; therefore, leaves, herbs, and flowers should be dried exclusively by the shade-drying method.

Sun-drying can be used without detriment for roots, rhizomes, and bark; however, it must be borne in mind that it is unsuitable for glycoside-bearing and certain alkaloid-bearing raw materials (as it reduces the alkaloid content in the rhizomes of plants such as Scopolia and Senecio). This method is typically used for the final drying of "grain-type" raw materials.

Artificial thermal drying is applied to various morphological groups of raw materials. It ensures rapid dehydration and can be used under any climatic conditions. It is subdivided into convective and thermal-radiation drying.

Convective drying is carried out in batch or continuous dryers. Numerous designs of dryers can be classified into stationary and portable types.

Portable dryers come in various designs. Fruit and vegetable dryers are best suited for drying succulent berries (such as raspberries and blueberries).

For thermal drying of medicinal plant raw materials in rural settings, the following are used:

stoves.

Based on the method of material loading and unloading and the operational conditions of the drying process, dryers are divided into two types: batch and continuous. Batch dryers mainly include chamber, steam, fire-heated, solar, and electric dryers. Continuous dryers are represented by belt dryers.

Each type of medicinal plant raw material requires specific drying conditions that are scientifically substantiated and described in relevant instructions, yet general drying rules also apply.

Buds, which typically contain resinous substances and essential oils in their outer leaves, are dried rapidly and at a moderate temperature, spread in a thin layer and stirred frequently to prevent molding. With slow drying, the inner leaves of the buds darken, mold appears at the fracture site in the form of a white coating, and they acquire an unnatural odor, rendering them unsuitable for use.

Bark contains significantly less moisture compared to other plant parts. It is usually dried in the open air while being protected from dew and rain, and it should be brought indoors at night. Due to The oxidation of Tannins, bark almost always darkens, acquiring a brownish color. Properly dried bark snaps with a crack rather than bending.

Leaves are dried by spreading them in 2-3 layers. Large leaves, such as those of coltsfoot (Tussilago farfara), should be laid out individually. If necessary, their petioles are broken or cut off.

Flowers are spread in a thin layer so that they do not need to be stirred. Stirring causes flowers to curl their petals, and some of them darken, acquiring a poor appearance and an unnatural color.

Herbs, when harvested in limited quantities, are most often tied loosely into small bundles and hung on ropes in well-ventilated rooms or attics under an iron roof. Although this method is convenient, under unfavorable conditions the leaves inside the bundle often darken. Properly dried leaves and herbs crumble easily when rubbed in the palm of the hand.

Dry fruits and seeds (such as anise, dill, flax, and mustard) contain a small amount of moisture and largely lose it even before harvesting; therefore, such raw materials only require final drying in dryers, a well-ventilated room, or in the open air.

Roots, rhizomes, tubers, and bulbs are first cleaned of soil and dead parts. Thick roots and rhizomes, unless they are routinely cut into pieces, are dried at a low temperature.

Standardization of raw materials is performed to remove debris and eliminate defects caused by improper harvesting and drying—in other words, to bring the raw material into a marketable condition where its purity fully complies with standard requirements. The main sorting operations include:

- cleaning the raw material from unwanted or mistakenly harvested parts of the source plant;

- removing defective (rotted, moldy) plant parts as well as those that have lost their natural coloration;

- sifting to remove excessively pulverized particles;

- cleaning raw materials from organic and mineral impurities.

Often, all these operations are performed simultaneously using mechanized screens with a set of sieves.

General-purpose sorting machines include various designs of winnowing-sorting machines. They are suitable for cleaning seeds and berries. Special-purpose sorting machines, known as "inclined belts" or "sorters", are also used. These are separators where belts can move at different angles, allowing impurities to be separated by both mass and size. In this way, anise fruits are cleaned of coriander impurities.

Packaging ensures the preservation of the quality and quantity of raw materials during storage and transportation. For each type of raw material, There is a corresponding standard-defined packaging: single and double fabric bags, paper bags, plywood boxes, etc.

Containers must be sturdy, clean, dry, free of foreign odors, and uniform for each batch of raw material. Among the listed types of containers, bags and bales are the most commonly used.

Bag containers are used to pack about 70% of medicinal plant material types (seeds, berries, small and cut roots, rhizomes). The capacity of the bags is utilized as close as possible to the standard-established nominal value of 50 kg.

Bales are formed by compressing raw materials using hydraulic, electric, or screw presses. All bales are covered with a protective fabric sheath. The standard weight of a bale is 100 kg, and it is reinforced with wire bands for durability.

Storage of medicinal raw materials. Storage conditions must ensure that the raw materials lose neither their appearance nor their active constituents.

Raw materials are stored by sorting them into groups: poisonous and potent, essential-oil-bearing, fruits and berries—each in a separate room, on racks, with the bottom tier at least 15 cm off the floor, stacked in piles no higher than 2.5 m for berries, seeds, and buds, and up to 4 m for Other types of raw materials.

Raw materials stored in the warehouse are repositioned annually, and at the same time, the facility is disinfected.

The shelf life of each type of raw material is established by the relevant regulatory document.