Pharmacology

Pharmacology

A supreme symphony of Nature and Knowledge . Ayurveda seeks to enhance the vitalities of life by drawing on the essence of Nature . Illness , according to Ayurveda , is caused by the imbalance of the humors (doshas). So medicines derived from the rare herbs of Nature are used not only to treat a particular disease but to restore complete harmony to the body .

PHARMACOLOGY

DRAVYA(SUBSTANCE /DRUG)

PURIFICATION OF DRAVYAS

CLASSIFICATION BASED ON THE THERAPEUTICAL USES

NOMENCLATURE OF BASIC MEDICINAL PREPARATIONS

Classification of Ayurvedic Drugs

Ayurvedic pharmacology is termed dravyavignam . Here dravya means substance and vignan is wisdom and dravyavignan , the science of drugs . The dravya or drug is panchabhautik (composed of the Five great Elements ) and Ayurvedic pharmacology is interpreted on the basis of the theory of the Five Great Elements :

Sarvam dravyam pancha bhautika masminnarthe

GUNA(quality) DRAVYA(substance/drug) KARMA(effect)

According to predominant element According to source

PARTHIVA JANGAMA

APYA AUDBIDHA

TAIJASA BHAUMA

VAYAVYA

NABHASA

Dravyas

Five categories of dravyas

Before going in to the action of the different dravyas to induce the system back into equilibrium ,let’s take a look at the various classification of dravyas . Dravyas are classified in to five groups according to the predominance of one inherent element : Parthiva( Earth) , Apya (Water), Taijasa(Fire) , Vayavya (Air), Nabhasa (Ether).

They are again classified into three kinds according to the source from which they are derived .

Jamgama – Animal source

From various sources in the animal kingdom , honey , milk and milk products , fat , bile, bone , bone-marrow, tendon , horn, flesh, blood, semen, excreta, urine, and so on are obtained for the preparation of drugs.

Audbidha

There are four vegetable sources :

1.Vanaspati - Flowerless trees with fruits

2.Vanaspatya - Tree whose fruits develop from flowers

3.Oshadi - Plants which die after development of the seeds

4.Viruth - Plants which grow by climbing

Bhauma (mineral source)

Gold ,silver ,copper, tin, iron, and their oxides, arsenous sulphide ,arsenous disulphide, salt ,calcium, antimony and so on are used in medicines .

Dravyas

Vegetal parts used as medicines include the root (mula), bark(tvak), pith(sara), gum resin(niryyasa),culm(nalam), leaf(patra), leaves and flowering top(pallava), rhizome and bulb(kanda), flower(pushpa), fruit (phala), juice(swarasa) , milky exudation (ksara) and vegetable alkali(ksara). All the classical texts provide description of various plants and their medicinal qualities .

The Samavayi of Dravyas

Yatrasritah: karmagunah

Karanam samavayiyat tadh dravyam

- Charaka

Kriyah gunavat samavayi karanam dravyam –Sushruta

The qualities inherent in a dravya are called Karma. Guna and Karma are inter-related and basically have no separate entity. This is known as Samavayi.

Karma (Action )

Rasa , Guna , Veerya, Vipaka and Prabhava are the various stages of transformation a drug undergoes before it causes an ultimate effect in the body . The ultimate effect of a drug on the human system is termed Karma.

Rasa(Taste)

The guna (quality ) of a substance or drug is represented by its rasa (taste) and the dravyas are classified according to any one of the six rasas contained in them .

Each rasa is the resultant of the predominance of any two of the five bhutas (elements) which cause a specific impact on the doshas (humors) of the human body .Different combinations and permutations of rasas ,around 63 ,are prescribed to restore the distributed equilibrium of the humors .

The rasa of a dravya is identified by prathayaksha( direct observation ), anumana (inference) and upadesa (authoritative testimony).

The Six Rasas

Madhura Rasa (sweet)

It is cool , heavy , and viscous . Sweet taste promotes handsomeness and longevity and helps the overall growth of the body and tones up Ojas (vitality ). It is good for bettering the complexion , for sweetness of voice and cheerfulness of disposition and also nourishes the sense organs .It is pittahara (restores vitiated Pitta ) and vatahara (alleviates morbid Vata). It stimulates the healing process and is good for breast – feeding mothers . Earth and water elements predominate in madhura Rasa.

Amala Rasa (Acidic)

It is viscous . It stimulates the salivary glands and promotes appetite and digestion .It is also a carminative . Having earth and fire as its prominent components , it provokes the Kapha and Pitta.

Lavana Rasa (saline)

It is neither heavy nor viscous . Its strong taste causes salivation and enhances the flavour of foods . It acts as a carminative and a laxative . With water and fire being predominant . It always the Vita .

Katu Rasa (Pungent or Acrid)

It is light and hot because of the predominant and fire elements . Katu Rasa acts as an anthelmintic , dilates the body channels and allays Kapha . It relieves intestinal dropsy and helps in the elimination of waste products from the body . According to Charaka , Katu Rasa stimulates gastric secretions and enhances the clarity of the sensory organs .

Tikta Rasa (bitter)

It is dry and light . Ether and air are the main components in substances that taste bitter. In action , it is paraciticidal and antipyretic . It is also a carminative .

Kashaya Rasa (Astringent)

Substances that taste astringent are composed primarily of earth and air . It dries up moisture and allays the provoked Kapha and Pitta . Charaka says , ‘’The astringent taste is sedative and promotes healing of injuries and fractured bones .‘’

How Rasas Act on the Humors

1.Madhura Increases Kapha

2. Amala Liquefies Kapha , vitiates both Kapha and Pitta

3. Lavana Incites Kapha , vitiates Pitta

4. Katu Increases Pitta and vitiates Vata

5.Tikta Vitiates Vata

6. Kashaya Increases Vata

Guna (Healing Property)

The physical and chemical properties of a dravya which act as healing agents are termed its gunas . Vagbhata classifies gunas into 20 kinds:

Guru (heavy) Leghu(light )

Manda (dull) Teekshna (pungent /sharp)

Hima (cold) Ushma (hot)

Snigdha (unctuous) Rooksha (non-unctuous)

Slakshna (smooth) Khara (rough)

Sandra(dense) Drava (liquid)

Mridu(soft) Katina(hard)

Sthira (stable) Sara (fluid)

Sukshma (stable) Sthula(gross)

Visada(non-slimy) Picchila(slimy)

Veerya ( potency)

A drug causes a systematic effect in the alimentary canal , either hot or cold , due to the metabolic process it triggers . This is because of the policy of its component gunas , which is termed as Veerya . Veeryas are classified in to two Ushma and Sita .

Vagbhata says that drugs possessing Ushma veerya causes giddiness , thirst ,sweating , heat and quick digestion . They reduce Vata and Khapha. On the contrary , the Sita veerya drugs cause a soothing and nourishing effect.

Vipaka

Every one of the six rasas undergoes transformation with digestion due to the action of digestive juices in the intestinal tract . The transformed state of one rasa into another is called Vipaka .

Vipakas are classified into three types .

1. Maddhura Vipaka (sweet)
Promotes smooth discharge of urine and faeces and induces secretion of Kapha .

2. Amla Vipaka (acidic)
Promotes the excretory functions

3.Katu Vipaka (pungent )
causes constipation

According to Shshruta , gurutva and laghutva are the two fundamental qualities of the bhutas (elements). Hence there are only two vipakas inadhura (sweet)and katu( acidic ).

Prabhava (specific Property)

Usually the effect of a drug on the human body is determined by its panchabhautik (‘five elemental’) and some drug that possess specific properties which cannot be defined by these critera. Such a property is termed Prabhava.

Pharmaceutics

Medicines in Ayurveda are termed Oushadams and diseases are whatever causes pain (Vyadhi).

Osham rujam dhavati eti oshadi – that which kills (allays) pain is Oshadi . Oshadi means plants which are used as drugs .

Purification of dravyas

Dravyas derived from animal ,vegetable and mineral sources are purified before they are used for preparation of drugs . The process of cleaning is called Shodhana

In the conventional process of cleaning , 12 different methods were followed . Though modern mechanical devices have introduced some changes , the basic concepts of purification have not changed . Traditional methods include washing and three kinds of filtration. The other important methods practiced and maceration, dialysis ,

Various Ayurvedic Medicinal Preparations

Swarasa (extract)

The dravya from which extract is to be taken should be fresh and juicy . It is cut in to small pieces and sometimes slightly crushed . Then with the help of a squeezer, the swarasa or extract is taken . Dravyas , from which thr extract cannot be squeezed out, like those of a semi-woody nature , should be cut in to small pieces , crushed , and then a paste prepared . This paste is then squeezed for the extract .

Kashya

Kashaya means decoration or extract . There are more than 1000 kinds of Kashayas .

Drugs in their raw form are cut into small pieces , crushed , and then boiled in water in an earthern vessel till the volume is reduce to a quarter . In some cases , the volume is further reduced to half . The decoration thus obtained is strained through fine cloth or
muslin .

Sita Kashya (Cold infusion )

Crushed dravys are steeped in water in a closed vessel for 12 hours . Water that has been boiled and cooled or clean rainwater can be used . After the stipulated time , the contents are passed through s filter and the liquid thus obtained is the Sita Kashaya . The sold residue left in the filter can be pressed to obtain the remaining extract .

Phanta Kshaya

Here a dravya is crushed and mixed with water and then the mixture sieved to obtain Phanta Khashaya.

Kalka(Paste)

The dravyas are cut into pieces and crushed . While adding water, it is then ground on a stone with a muller to get a paste of thick consistency . In some cases , other liquids are used. In the case of fresh , juicy dravyas , not much water or any other liquid is used .

Churna (Powder )

The first step is to cut the dravyas into small pieces and crush them with the help of a pestle and mortar . To obtain a fine powder , it is further ground on a stone with a mallet . The powder is then sifted with a piece of line cloth or a new sieve with fine meshes .The grains left on the sieve can further be crushed and sifted to obtain more of the therapeutic powder.

Asava

Adding powered medicine , raisins , jaggery and Thathirippoo, a flower that act as a fermenting agent , to water that has boiled and cooled makes asavas . The mixture is stored in earthern pots for around 30 days for fermentation and sedimentation. The fluid obtained after removing the sediment is used for treatment .

Arishta

Adding mixture is kept sealed in earthen pots for 30 days. The porosity of the earthern pots helps maintain a temperature of around 27 degrees inside which facilitates fermentation . After 30 days, the mixture is strained and kept for sedimentation , for 10 to 15 days , during which contact with air is maintained . The solution obtained after removing the sediment is the arishta.

Lehya

The lehya , which is of semi- solid form, is made by mixing Kashaya , swarasa , water and a sweetening element (kalkanda , jaggery and so on ) over a fire until they are blended well. After adding Prakshepa churna to this blend , it is left to cool and then honey , ghee ((clarified butter) and oil are added to obtain the lehya . In some cases , the lehya will be ready for use before adding honey , ghee and oil.

Thaila

Adding medicinal elements to an oil base , usually gingelly oil , makes a thaila . Thailas can either be applied externally or taken internally .

The avarthy or potency of a thila is improved by adding more and more ingredients everyday over a fixed period of time .

Sevya

A thaila that is taken internally is called a sevya . Here , the base is either gigelly oil or caster oil.

Kuzhamhu

This is a specially of kerala and is made by adding the medicinal element to a suitable base oil ,castor oil and ghee.

Ghruta

Heating ghee that has been mixed with medicine to the consistency of a thaila makes ghruta .

Gulika

Medicines in the form of tables or pills are known as gulikas . Medicinal paste is first rolled into small balls and dried in the sun to make the gulikas .

Vadaka

Vadakas are made in the same way as gulikas but are bigger in size .

Combination Medicines

There are also certain very popular ‘ combination medicines ‘- combination of different drugs that produce the same result . The purpose of such combination is to cause a synergistic effect with a smaller dose .

The most popular of such drugs are :

Ashtavarga Pancha kola

Brihat Panchamula Pancha tikta

Chaturjata Triphala

Chaturbija Trikatu

Dasamula Triiatha

Laghu Panchamula Trimada

Pancha valkala Trinapannchamula

Pancha pallava

Classification of Drugs Based on Therapeutic Uses

Drugs have been grouped into several categories according to their pharmacological actions and therapeutic uses . While Charaka enumerated 50 such groups of medication . Sushruta mentioned 37. Some of the most popular therapeutic classification mentioned in the classical texts are

1. Jivaniya (restoratives and vitalisers) –promote life . Usually earth and water elements predominate in such drugs .

2.Brumhaniya – strengthen and energize the body .

2. Lekhaniya (emaciating drugs )- reduce mass from the body . Fire and air elements predominate .

3. Bhedaniya- liquefy and expel accumulated impurities .

Classifications of Drugs Based on Therapeutic Uses

4. Dipaniya (appetizers or stomachic agents )-stimulate the digestive fire .

5. Balya (tonics )- strengthen the nervous system and improves general health .

6. Sandhaiya (healing drugs ) – facilitate joining of broken parts , especially of bones and blood vessels .

7. Varnya (complexion promoting drugs )-help restore the lost colour and complexion of the skin after illness .

8. Krimighna (anthelmintics)- destroy parasitic worms .

9. Jwarahara(anti-pyretic)-reduce fever.

10. Kantya – good for the throat ; betters vocal clarity .

11. Hrudya (cordial )-good for the heart; hrudya literally means cordial , ie cordial to the whole system

12. Kasahara (anti-cough drugs )-relieve cough .

13. Visaghna (antidotes ) –counteract the effects of poison.

14. Vedanastapana (analgesics)-allevate pain .