Metals and Mineral Drugs of Ayurveda
Metals and Mineral Drugs of Ayurveda Metals like gold, silver, copper, lead, tin, and iron, sand (balu from river banks), lime and minerals like red arsenic (manassila), gems (manayah), salts (lavana), and red chalk (gairika) are indicated as drugs pertaining to earth (bhauma). In Indian metallurgy, the term loha is often used for metals like gold and silver and minerals containing metals (ores) are called dhatus. There are seven dhatus: suvarna (gold), rajata (silver), tamra (copper), trapa (tin), tiksna or ayas (iron), sisa or naga (lead), and vaikrintaka.11 Salts or lavanas are mentioned under the parthive substances. According to Charaka, there are five salts: sauvarcala, saindhava, vida, audbhida, and samudra. Mani and ratna, being synonyms for each other, stand for the modern term “jewel” or “gem.” Mercury is considered eighth metal in rasa shastra. It earned the supreme position among the minerals and metals. The learned Acharyas also studied the relation and effects between these metals and planets over the human body and called them grahanga navaloha. Metals are grouped as shuddha, sishra, and pooti loha.
The calcined forms of metals that are termed bhasmas in Ayurveda are referred to as parpams and kushta in Siddha and Unani-tibb, respectively. Kushta literally means to kill; in medical terms it is detoxifying the toxic properties of a toxic metal.12 Although bhasmas are regarded as chief metal-containing pharmaceuticals of Ayurveda, there are several other preparations prepared from metals. Some of these pharmaceuticals are described below. Bhasma Animal derivatives such as horns, shells, feathers, and metallic and nonmetallic minerals are normally administered as bhasmas. A bhasma means an ash obtained though incineration. The starter material undergoes an elaborate process of purification (shodhana). This process is followed by the reaction phase, which involves incorporation of some other mineral and herbal extracts. Then the material in pellet form is incinerated in a furnace.
The end product is expected to be a nontoxic material. Examples include swarn bhasma, shankha bhasma, and tamra bhasma. Parpati These are specialized mercury preparations. The name is derived from the method by which flakes of the compound are obtained. A black sulfide of mercury is obtained by mixing purified mercury and sulfur. Other drugs as per the formula are added to this and mixed well by triturating them in mortar and pestle. A shallow pit is made in fresh cow dung and a banana leaf is placed. The melted compound is poured onto the leaf and is covered with another leaf. Fresh dung is spread on it evenly. When it is cooled the flakes are removed and powdered. Rasayoga Rasayogas are compound formulations containing mercury and sulfur (in the form of kajjali) with other metals or minerals. Most of the ingredients contained in a rasayoga are added in the form of bhasmas. The final form may be either a pill or powder. Sindoora Sindoora are prepared by the elaborate process of sublimation. This procedure is termed kupipakwa vidhi and the sublimed mineral available on the neck of the sublimation glass flask is called sindoora. Sindoora preparations are considered to be more potent than bhasma preparations. Types of Bhasma Attempts have been made to classify various bhasmas. They have been classified on the basis of color and appearance. A more scientific way of classification is on the basis of dominant metal and mineral group. According to this classification, bhasmas have been grouped as rajata group (silver), tamra group (copper), loha group (iron), pravala group (shells), etc. Often two metals and a metal with mineral are the ingredients of bhasmas. For example, Trivanga Bhasma contains lead, tin, and zinc. The metals yield three different types of bhasma corresponding to the nature of the ingredient used. They appear as best, medium, and inferior quality.
Mercury is always used as a basic substance in the process of marana. Preparation of Bhasma: General Procedures The name bhasma is generally applied to all metallic and nonmetallic substances that are subjected to the process of incineration and reduction to ash. Here it is applied to the metals, minerals, and animal products that are, by special processes, calcinated in closed crucibles in pits with cow dung cakes (puttam). Bhasmas are generally white, pale, or red. The color of the preparation primarily depends on the parent material. The following pharmaceutical steps are used to prepare bhasmas. Shodhana In Ayurveda, purification is called shodhana. Shodhana is the process through which the external and internal impurities of metals and minerals are removed. Chemical purification is different from medicinal purification. In chemical purification it is only elimination of foreign matters, whereas in medicinal purification the objects are involved in the
1. Elimination of harmful matter from the drug
2. Modification of undesirable physical properties of the drug
3. Conversion of some of the characteristics of the drug to different stages
4. Enhancement of the therapeutic action There are two kinds of shodhana. The first type, samanya shodhana (general purification), is applicable to the large number of metals or minerals as heating the thin sheets of metals and immersing them in oil (taila), extract (takra), cow urine (gomutra), and other materials. The second type, Vishesha shodhana (special purification), is applicable only to specific metals, minerals, and in certain preparations. Vishesha shodhana includes bhavana, svedana, nirvapana, and mardana. After shodhana bhasmas become soft and malleable for further processing and their metallic property is improved. The main apparatus required includes dola yantra, khalva yantra, and musha yantra.
Various procedures employed for shodhana are described below. When mineral drugs are heated in a furnace in the presence of dravaka, substances (liqueficants) like alkali and acid release their satva. This is the purest form of any herbal or mineral drug. All the metals except mercury are found in nature in solid state, and they all fuse under high temperature to attain a liquid state. When the temperature lowers they again return to their natural physical form (i.e., in the solid state). But these fused metals in the presence of some liqueficants do not return into their natural solid state even when the temperature lowers (i.e., the metals remain in liquid form). This method of obtaining metals in liquid form is called dravana and the obtained liquid metal is called druti. Druti holds superior character with respect to efficacy, toxicity, and increased shelf life than its native metals and retains its fluidity for a longer time with proper preservation. Shuddhavarta is a particular stage of heating when the fire becomes strong enough to yield the pure substance (metal, satva). At this time the flame becomes golden yellow. Marana Marana is essentially the burning process or calcination. The purified metal is placed into a mortar and, with a pestle, ground with the juice of specified plants or kashayas, mercury (in metallic state), or a compound of mercury such as mercury perchloride (sauviram), mercuric subchloride (ras karpur), cinnabar (ingalekam), or an amalgam of sulfur and mercury (kajjali) for a specified period of time. The metal that is intended for marana is known as a primary metal (pradhan dhatu); the other metal, which is taken in small proportions for the marana of the primary metal, is known as secondary metal (sahaya dhatu). Small cakes (chakrikas) are made with the ground paste of the minerals and dried under the sun. The size and thickness of the cakes depend on the heaviness of the drug and size.
The heavier the drug, the thinner the cakes. These cakes are dried well under the shade and placed in one single layer in a mud tray (sharava) and closed with another such tray; the clay-smeared cloth keeps both the lid and the container in apposition. The clay-smeared cloth is applied seven times and dried to seal the crucibles properly. A pit is dug in an open space and half the pit is filled with dried cow dung cakes. The crucibles are placed in the half-filled pit and are covered with cow dung cakes up to the brim of the pit. Fire is then ignited on all four sides and in the middle of the pit. When the burning is over, the contents are allowed to cool completely on their own. Marana differs with the nature of the substance to be calcinated. For example, organic substances such as herbs are burnt in open air, whereas inorganic substances such as metals like rajata (silver) are burnt in closed containers. In either case the end product is a bhasma of substance taken for marana.
For example, the end product in the case of silver (rajata) is called as rajata bhasma. Marana of inorganic substances is called puta and the process of marana of herbs in closed freshly made containers is known as puta paka.13 Bhasmas obtained by marana from primary metals together with herbs (mulika) are called mulika marita bhasma; the ones where the second metal is taken for the marana of primary metal are called parada (mercury) marita, or talaka (arsenic trisulphide) marita bhasma, depending upon the second metal used for the purpose. During the process the second metal would finally volatilize itself at the temperature of marana, leaving behind the bhasma of primary metal. Very few metals like copper or iron still bear some impurities after the marana. In such cases the whole process is repeated until a purified and therapeutically safer product for internal use is obtained. In addition, a process called amritikarana is done to make these metals safer. The process consists of heating the product from the marana procedure in the presence of some herbal materials to improve safety and therapeutic effect. In this process the required amounts of triphala decoction, cow’s ghritika, and dhatu bhasma are placed in an iron pot. Mild heat is applied until the medicinal fluids are completely evaporated. Bhasma that remains at the end of this process is safer and possesses higher therapeutic efficacy.