VASTI KARMA

PROBABLE MODE OF ACTION- AYURVEDIC VIEW

In Ayurvedic classics, Acharyas have tried to explain actions of Vasti with suitable analogism(Ch.Si.1/31)

As tree irrigated in its root level attains nourishment for whole tree, In the same way, Vasti drugs given through Guda {Rich in blood vessels, lymphatic & nerves} Nourishes all the limbs & organs of the body. By the above mentioned reference, a collation of information about Guda Sharira (structure of Anus), its relations, its physiology etc. gives compendious information about it.

Guda (Anus) is one of the Pranayatana, where all twelve Prana dwell predominantly. Guda (Anus) is a Mamsa marma of Sadyapranahara type. Being a Marma it has roots of all four types of Sira embedded in it viz. Vatavaha, Pittavaha, Kaphavaha and Shonitavaha..

Due to its Sadyapranahara nature, Guda (Anus) is highly sensitive. Even a mild stimulation to it, say, by Vasti drugs and procedure may sensitize the whole body by vigorous action of Vayu through all the Siras present in the body. This physiology confirms immediate and all pervasive action of Vasti drugs even though the Vasti lies in Pakvashaya.

Relations of Guda (Anus):

Apana Vayu-             Anus is the seat of Apana Vayu

Prana Vayu-              Being Sadyapranahara Marma

 Vyana Vayu -                       Vyana is all-pervasive

 Samana Vayu -         It moves all over the Koshtha.

Pachaka Pitta -          Helps in digestion

      Sira, Snayu, Sandhi, Asthi & Mamsa Sannipata- as it is a Marma

Kala-                           Maladhara, Asthidhara and Majjadhara.

Dhatu-                                    Rasa, Rakta, Mamsa, Meda, Majja & Shukra.

From the above-sited relevance it may be said that, Vasti influences whole body. However, it acts mainly on the structures related to Guda (Anus). If Apana is controlled in its own abode other four Vayu can be bridled automatically.

Vasti drugs in Pakvashaya acts on whole body in a same way that of sun, which though placed in the sky, causes evaporation of water on the earth. The Virya (potency) of Vasti dravya is first taken up by Apana Vayu, i.e. it acts or influences the Guna of Apana Vayu with which it comes in contact first. Consequently the Samana Vayu is also affected followed by Vyana, Prana and Udana. By the Guna of Vasti dravya, the vitiated Vayu regain their normal state and supports the body. They also bring vitiated Pitta and Kapha in their normal state, and the five types of Vayu nourish their respective Sharira-Bhuta Guna. The Virya (potency) of dravya (substance) are propagated by the Vyana in Tiryaka or lateral direction, by the Apana in downward direction and in upward direction by Prana, just as water pipes carry water to the different parts of the field similarly the “Harini” (Channels) carry the Gunas of the Vasti dravya to every part the body, hence a Vasti which is appropriate will with the help of Vata, Pitta and Kapha through the Siras will spread in all over the body and cures even the most difficult disease.(A.S.Ka.5/24)

Pakvashaya is the place where Poshakamsha (nutritive substances) originates and supplies the nutrition to all Vayu. As Vasti is introduced in its Udbhavasthana, it has capacity to control all the five Vayu. However it acts more on Samana and Apana because it has direct contact with their places.

PROBABLE MODE OF ACTION- MODERN VIEW

A.    Absorption in systemic circulation

B.     Colon cleansing

C.    Gut brain theory

D.    Influence on Bacterial Flora

A)    ABSORPTION IN SYSTEMIC CIRCULATION

Vasti may be absorbed by: diffusion, filtration, osmosis or by adsorption depending upon substance used in it.

Though small intestine is supposed to be an important organ for absorption of food & drugs colonic administration of drug has a specific importance. Thus colon targeted drug delivery is gaining popularity. It is a concept that is being used in Ayurveda in the form of Vasti.

“Colon Targeted Drug delivery, an old concept in new perspectives”

Why colon targeted drug delivery needed?

v  Targeted drug delivery to the colon would ensure direct treatment at the disease site, lower dosing and fewer systemic side effects.

v  Colon-specific drug delivery system is considered to be beneficial in the treatment of colon diseases.

v  The colon is a site where both local or systemic drug delivery could be achieved, topical treatment of inflammatory bowel disease, e.g. ulcerative colitis or Crohn’s disease.

v  A number of others serious diseases of the colon, e.g. colorectal cancer, might also be capable of being treated more effectively if drugs were targeted to the colon.

v  Formulations for colonic delivery are also suitable for delivery of drugs which are polar and/or susceptible to chemical and enzymatic degradation in the upper GI tract, highly affected by hepatic metabolism.

v  COLON ANATOMY

The GI tract is divided into stomach, small intestine and large intestine. The large intestine extending from the ileo-caecal junction to the anus is divided in to three main parts. These are the colon, the rectum and anal canal.

v  The entire colon is about 5 feet (150 cm) long, and is divided in to five major segments. Peritoneal folds called as mesentery which is supported by ascending and descending colon.

v  The right colon consists of the caecum, ascending colon, hepatic flexure and the right half of the transverse colon. The left colon contain the left half of the transverse colon, descending colon, spleenic flexure and sigmoid.

 

Fig no. 1.2: Showing Anatomy of Large intestine and intestinal wall

v  The rectum is the last anatomic segment before the anus.

v  The major function of the colon is the creation of suitable environment for the growth of colonic micro-organisms, storage reservoir of faecal contents, expulsion of the contents of the colon at an appropriate time and absorption of potassium and water from the lumen.

v  The absorptive capacity is very high, each about 2000ml of fluid enters the colon through the ileo-caecal valve from which more than 90% of the fluid is absorbed.

v  On average, it has been estimated that colon contains only about 220 gm of wet material equivalent to just 35 gm of dry matter. The majority of this dry matter is bacteria. The colon tissue contains the villi, lymph, muscle, nerves, and vessels.

Drug absorption in the colon:

Drugs are absorbed passively by either paracellular or transcellular route. Transcellular absorption involves the passage of drugs through cells and this is the route most lipophilic drugs takes, where paracellular absorption involves the transport of drug through the tight junction between cells and is the route most hydrophilic drug takes. The colon may not be the best site for drug absorption since the colonic mucosa lacks well defined villi as found in the small intestine. The slower rate if transit in colon lets the drug stay in contact mucosa for a longer period than in small intestine which compensates much lower surface area.

Standing gradient osmosis:

Water absorption at the colon typically proceeds against a transmucosal osmotic pressure gradient. The standing gradient osmosis is a term used to describe the re-absorption of water against the osmotic gradient in the intestines. This hypertonic fluid creates an osmotic pressure that drives water into the lateral intercellular spaces by osmosis via tight junctions and adjacent cells, which then in turn moves across the basement membrane and into the capillaries.

“Why Vasti may prove better than oral drugs for colon targeted drug delivery?”

As a site for drug delivery, the colon offers a near neutral pH, reduced digestive enzymatic activity, a long transit time and increased responsiveness to absorption enhancers; however, the targeting of drugs to the colon is very complicated. Due to its location in the distal part of the alimentary canal, the colon is particularly difficult to access.

In addition to that the wide range of pH values and different enzymes present throughout the gastrointestinal tract, through which the dosage form has to travel before reaching the target site, further complicate the reliability and delivery efficiency. However Vasti has-

Ø  Direct access to colon.

Ø  Quick action as transit time is not an obstructive factor.

Ø  No enzymatic degradation as in case of oral drugs targeting colon while travelling from upper G.I. tract.

Successful delivery through this site also requires the drug to be in solution form before it arrives in the colon or, alternatively, it should dissolve in the luminal fluids of the colon, but this can be a limiting factor for poorly soluble drugs as the fluid content in the colon is much lower and it is more viscous than in the upper part of the GI tract.

Vasti itself is a thick liquid consistency fluid providing enough solution media for drug absorption.

In addition, the stability of the drug is also a concern and must be taken into consideration while designing the delivery system. The drug may potentially bind in a nonspecific way to dietary residues, intestinal secretions, mucus or faecal matter.

The volume of Vasti is considerably large that ensures required dose delivery & the protocol for administration is well designed  by Acharyas to avoid faecal matter or dietary residue  binding by stating do’s & don’ts for Vasti administration.

The resident microflora could also affect colonic performance via metabolic degradation of the drug. Lower surface area and relative tightness of the tight junctions in the colon can also restrict drug transport across the mucosa and into the systemic circulation.

Purvakarma like local Snehana-swedana & slightly warm temperature of the Vasti may increase colonic permeability; thus increasing the absorption.

Chief ingredients of VaitaranaVasti are having Tikshna Gunas; on virtue of its active photochemicals it’s effect in Katishool, Amavata therapy may be achieved through absorption of Vasti Virya i.e. entry of active principles in systemic circulation through colon.

B). COLON CLEANSING

Colon cleansing come with many beneficial effects out of which some are as follows:

v  Removal of wastes and toxins:

With irregular bowel movements and lack of defecation, faecal wastes start accumulating in the colon. Digested and undigested food from the stomach travels to the small intestines. Here, only nutrients from the food we eat are absorbed in the small intestines and the rest of the food matter containing dead cells, unhealthy or dead microbes and other harmful bi-products then move on to the large intestine or colon. These are largely waste materials with little nutrients except for some water and electrolytes which can be absorbed by the colon for use in our body. However, if these wastes are not removed from the body on daily basis, they began to putrefy and a bacterial load starts to build up and in no time our colon is filled with toxic substances.

Certain unhealthy bacteria and microbes flourish in these waste products which will undoubtedly cause harm to our body eventually. A parasite colon cleanse will effectively kill parasites and destroy their eggs. Colon cleansing helps to remove these wastes and toxins from the body before autointoxication takes place. At the same time, colon can slowly recover its intended functions and return to its healthy state.

v  Better Absorption:

One of the major effects of colon cleansing is better absorption. The frequent layering of toxins and wastes over the intestinal walls in the colon blocks the function of the villi. The villi are hair-like protrusions in the intestines. The purpose of the villi is to slow the passage of food, and to allow food particles to be trapped among these finger-like villi. This allows the blood inside the villi to absorb nutrients in the digested food. Though the colon only absorbs electrolytes and water, it still performs a very important function as our body is made up of 70% water. If the function of the colon is impaired, there is a likelihood of dehydration occurring. Therefore, when the wastes and toxins are quickly removed from the colon, the villi can perform their functions readily.

v  Function enhancement of other organs:

An unhealthy colon affects all the other organs as well. When a colon is stuffed it compresses the liver, disturbing its functions. The liver is one of the major organs for toxin removal in the body together with the colon, kidneys and skin.

The liver's role in detoxification is to convert and detoxify harmful toxins into substances that can be safely eliminated from the body. When digestion is poor, bacteria in the intestines began to multiply when putrefaction takes place and create toxins. These toxins can damage the mucosal lining of the intestine, which increases its permeability and allows toxins to enter the bloodstream and gain systemic access to all areas of the body. This places additional stress in both the liver and kidneys. An unhealthy liver leads to an unhealthy kidney this is a vicious cycle.

A healthy colon helps to remove the wastes before they become toxic. So, having a healthy colon is the first major step to ensure that the other organs can perform their functions efficiently.

Impaired functioning of colon leads to accumulation of toxins which can be stated in Ayurvedic terms as Ama formation. Thus by colon cleansing action Vasti prevents Ama formation which is responsible for deterioration of the amavata and katishoola vikara.

C)    Influence through ENS (Enteric Nervous System)

v  ENS (Enteric Nervous System) is Substantial group of neurons

v  It is capable of Autonomous reflex without influence of central nervous system.

v  More than 500 million neurons present in the ENS (Enteric Nervous System) so it’s called “second brain”.

v  There are so many similarities between CNS-ENS regarding cellular structure, neuro-peptide secretion and specific functions.

v  And recent studies have shown that there is great influence of CNS and ENS (Enteric Nervous System) on each other.

In this way, Vasti may produce Neuromuscular remodelling, pain modulation by influencing ENS (Enteric Nervous System) and there by CNS (Central Nervous System).

D) Influence on Bacterial Flora

v  Vasti influence the normal bacterial flora thus it increases the endogenous synthesis of Vitamin B12, Vitamin K etc. Vasti makes the whole metabolism normal.

v  Production of Thiamine with the help of bacteria, which is necessary for nerve conduction and which is produced in large intestine, may be controlled by Vasti.