Ayurveda is considered by many scientists to be the oldest healing science. In Sanskrit, Ayurveda means “The Science of Life.” Ayurvedic knowledge originated in India more than 5,000 years ago and is often called the “Mother of All Healing”. Ayurveda translates into knowledge (Veda) of life (Ayur) and is one of the oldest and still widely practiced medical systems in the Indian subcontinent.
The concept of Ayurvedic medicine is to promote health, rather than to fight disease, and Ayurveda in daily life aims at maintaining harmony between nature and the “individual” to ensure optimal health.
Ayurveda contains 8
branches of sciences and 10 different diagnostic tools based on tridosha theory
(three humours of body). Ayurveda comprises of various types of medicines
including the fermented forms namely arishtas (fermented decoctions) and asavas
(fermented infusions). These are regarded as valuable therapeutics due to their
efficacy and desirable features.
Arishtas and asavas are
self-generated herbal fermentations of traditional Ayurvedic system. They are
alcoholic medicaments prepared by allowing the herbal juices or their
decoctions to undergo fermentation with the addition of sugars. Arishtas are
made with decoctions of herbs in boiling water while asavas are prepared by
directly using fresh herbal juices. Fermentation of both preparations is takes
place by the addition of a source of sugar with dhataki (Woodfordia fruticose) flowers. Many preparations contain additional
spices for improving their assimilation. They are moderately alcoholic (up to
12% by volume) and sweetish with slight acidity and agreeable aroma. Presence
of alcohol in the preparation shows several advantages, like better keeping
quality, enhanced therapeutic properties, improvement in the efficiency of
extraction of drug molecules from the herbs and improvement in drug delivery
into the human body sites.
Indian Ayurvedic literature that included
arishta and asava are Charaka Samhita, Sushruta Samhita, Astanga Hridaya etc.,
Asava-arishta is a novel
yet least exploited continuous hydro alcoholic extraction method, being
traditionally used in Ayurveda. This advanced dosage form results in the
transformation of several phytochemical compounds present in the herbs, thereby
either rendering them less toxic or more potent, besides helping in their
faster absorption
Preparation
of Arishta and Asava
The method of preparing
asava arishtas is known as sandhana kalpana in Ayurveda. General methods used in
the extraction of medicinal plants in asava and arishta are infusion and
decoction.
Decoction:
In this process, the crude drug is boiled in a specified volume of water for a
defined time; it is then cooled and strained or filtered. This procedure is suitable
for extracting water-soluble, heat-stable constituents. This process is
typically used in preparation of Ayurvedic extracts called “quath” or “kawath”. The
starting ratio of crude drug to water is 1:4 or 1:16. The volume is then
brought down to one-fourth its original volume by boiling during the extraction
procedure. Then, the concentrated extract is filtered and used as such or
processed further.
Infusion:
Fresh infusions are prepared by macerating the crude drug for a short period of
time with cold or boiling water. These are dilute solutions of the readily
soluble constituents of crude drugs.
The basic equipment required for preparation of arishta and asava is an
earthen pot sufficiently large and glazed, porcelain jar of suitable size; a
lid to close the vessel, a cloth ribbon to seal the vessel; a paddle like
stirrer; a clean cloth of fine and strong texture for filtering, vessel to keep
the juices or boil the drugs.
The major components are
divided into 4 types according to their specific role in the process. These
include: the main herbs from which
the extract or decoction is taken out. They yield drugs, which are
pharmacologically and therapeutically much important in the given medicine and
the name of the medicine is derived from these herbs denoting their importance.
The flavouring agents used in asava
and arishta contribute to the flavour of the medicine and also have their own
pharmacological action. The fermentation
initiator provides inoculum for the fermentation to start. The medium of sugars is required for
fermentation.
In Asokarishta, the main
herb is Asoka. Other components which contribute for flavours are Cuminum cyminum L., Santalum album L. and
Zingiber officinale Roscoe. Woodfordia fruticosa(L.) Kurz as fermentation
initiator and jaggery as a source of sugar are also present. Similarly in
Kanakasava, Kanaka is the main herb
while Piper longum L. and Zingiber
officinale Roscoe contribute for flavor. Woodfordia fruticosa are mostly used in asava and aishta. All parts
of this plant possess valuable medicinal properties and there is a heavy demand
for the flowers, both in domestic and international markets specialized in the
preparation of herbal medicines. This flower is pungent, acrid, cooling, toxic,
alexiteric, anthelmintic, and is useful in thirst, dysentery, leprosy, blood
diseases, toothache etc.,
Collection
of plant material and preparation before fermentation
ü Medicinal
substances such as roots, leaves or barks, etc. are cut into pieces, and
powdered or decoction. The basic drugs from which the extract is to be prepared
are first cleaned and rinsed in water to get rid of dirt. In the case of fresh
plants, they are cleaned, pulverized and pressed for collection of juice.
ü If
the drug is dry and to be used in the preparation of asava, it is coarsely
crushed and added to water to which the prescribed quantities of honey, jaggery
/or sugar are added.
ü If
it is an arishta, a decoction is obtained by boiling the drugs in the specified
volume of water as given in the recipe. The water used should be clean, clear
and potable. When the extracts are obtained, the sugar (cane sugar), jaggery/or
honey are added and completely dissolved.
ü The
sugar, jaggery and honey should be pure. The jaggery to be added should be very
old (prapurana) because fresh jiggery aggravates kapha and suppresses the power
of digestion.
ü The
flavouring agents are coarsely powdered and added to the sweetened extract.
Very fine powder of the flavouring agent is undesirable as it causes
sedimentation in the prepared medicine and its filtration is difficult.
ü In
asavas, the avapa (drugs which are added in powder form at the end) should be
one in tenth in quantity and honey should be three fourth in quantity of
jaggery.
ü The
earthen pot or jar intended for fermenting the medicine is tested for weak
spots and cracks and similarly a lid is also chosen. It should be prepared of
the soft mud collected from the silt in the bank of river or lake. It should be
greasy, thick, light and smooth. It should be free from holes or cracks and homogenous.
The internal surfaces of the pot and the lid are wiped with a clean dry cloth
and cow’s ghee is smeared on this surface to prevent oozing out of the
contents. The pot should be perfectly dry before ghee is smeared and if it be
moist, ghee will not stick, penetrate and block the pores. The infiltration of
the pot prevents oozing and strengthens the pot. Glazed porcelain ware may also
be used instead of earthen ware.
ü In
large scale, the fermentation is carried out in huge wooden vats with wooden
covers. The vat is made air tight. The filtration is carried out by electric
filter presses with filter sheets which efficiently separate the suspended
particles and isolate clear medicine. The powdering, grinding and mixing are
done by mills, pulverizers and mixing machines. The decoctions are prepared in
large steam jacketed boilers, heated by superheated steam under pressure.
Inoculum
When the pot or the jar
is ready, the sweetened and flavoured drug extract is poured into pot, up to
three fourth of the capacity. The unfilled space provides room for the
fermenting liquid when it rises up due to frothing and evolving of a large
amount of gases. Otherwise, the medium may damage the container and flow out.
Then, the inoculum has to be added to initiate fermentation. The process of
fermentation necessitates the presence of fermenting microorganisms, yeasts.
In the preparation of
alcoholic medicaments in the Ayurvedic Systems, the inoculum of yeasts comes
from the dhataki flowers, which
contain the wild species of yeast. These flowers are nectariferous and highly
tanniferous. The flowers contain the yeast spores in the dry nectariferous
region. The presence of tannin in flowers favours suitable environment for
yeast growth. The flowers are added and the contents are stirred well to
distribute the inoculum of yeast.
Apart from the fire flame
flowers (dhataki), if other ingredients like honey and resins (gum) are added they also contain wild yeasts.
When fire flame flowers
are not used in some preparations, the inoculum of yeasts is done either from
the mahua flowers, honey or resins
initiating the process of fermentation. The yeasts multiply rapidly by division
in a short time.
Finally, the vessel
should be closed and sealed. Sealing is done by winding around a long ribbon of
cloth smeared with clay on one surface. While sealing, the blank surface of the
ribbon should line the rim of the vessel and lid, the clay side should be
external.
After sealing, the vessel
is placed in a dark place without much circulation of air. It may be kept in a
grain store buried in a heap of grain or into a pit in the soil. Soft packing
of straw should be provided around the vessel to prevent breakage by any force
Fermentation
Process
The fermentation vessel
is left undisturbed for a month and then opened. The medicine is filtered and
taken for use. If the filtered medicine shows further sedimentation, it is
allowed to stand for few more days and again filtered to separate the sediment.
Fermentation processes
help in rupturing of cells of the herbs and exposure of its contents to the
bacteria and enzymes for transformation. Fermentation also creates active
transport system with dissolved constituents from the herbal material. There
are claims that yeast cell walls naturally bind heavy metals and pesticide
residues and act as natural cleaning system, making self-fermentation of herbal
products safer than powder decoctions
Merits of the Fermentation Process
1.Fermentation removes
most of the undesirable sugars from plant material, makes the product more
bio-available and eliminates side effects such as gas and bloating.
2.Fermentation extracts a
wider range of active ingredients from the herb than any extraction method
since the broth undergoes a gradient of rising alcohol levels.
3.Yeast cell walls
naturally bind heavy metals and pesticide residues and, therefore, act as a
natural cleansing system.
4.Fermentation removes
contaminants and can also lower the toxicity of some of the toxic components in
plants.
5.Fermentation actively
ruptures the cells of the herb, exposing it openly to the menstruum (solvents)
and bacteria have enzymes that break down cell walls to further assist in the
leaching process. Fermentation also creates an active transport system that
moves the dissolved constituents from the herbal material to the menstruum (solvents).
The
product of arishta and asava could end up with 79 products, of which 37 falls
into the category of asava, 38 into arishta and the remaining 4 arishta are
named as amirtha (Viswamritha, Balamritha and Swasamrutha, Vyoshamritha). These
products have also been commercialized. Arishta and asava is used for the
treatment of various problems in pediatrics, nervous system, blood and
circulatory system, respiratory system, digestive and excretory system, urinary
system, reproductive system, immune system, skin problems, worm infections,
general illness and infectious diseases etc.
Thus,
Arishta and asava are considered as best formulation in Ayurveda because they possess
better keeping quality, which is likely due to the contribution of fermentation
to preservation. The microbes involved in this process mediate this process;
enhanced therapeutic properties, which may be due to the microbial
biotransformation of the initial ingredients of arishta and asava into more
effective therapeutics as end products, alcohol-aqueous milieu, which is also
produced by microbes; improvement in drug delivery in the body is also increased
due to alcohol-aqueous milieu. These products in general possess preservative
properties, potentization of drug due to biotransformation mediated by native
microbes
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