Rauwolfia consists of dried roots of Rauwolfia serpentina Benth., belonging to family Apocynaceae.
RAUWOLFIA
Synonyms
Sarpagandha, Chandrika; Chootachand; Indian snake root.
Biological Source
Rauwolfia consists of dried roots of Rauwolfia serpentina Benth., belonging to family Apocynaceae.
Geographical Source
It is an erect, evergreen, small shrub native to the Orient
and occurs from India to Sumatra. It is also found in Burma, Thailand,
Philippines, Vietnam, Indonesia, Malaysia, Paki-stan and Java. In India it
occurs in the sub-Himalayan tracts from Sirhind eastwards to Assam, especially
in Dehradun, Siwalik range, Rohelkhand, Gorakhpur ascending to 1,300 m, east
and west ghats of Tamil Nadu, in Bihar (Patna and Bhagalpur), Konkan, Karnataka
and Bengal.
Cultivation and Collection
Rauwolfia grows in tropical forests at an altitude of 1,200–
1,300 m at temperature 10–40°C. There should be enough rain or irrigation for
its cultivation. The soil should be acidic (pH 4–6), clayey and manure is
applied for better crop. Propagation is done by planting seeds, root cuttings
or stem cuttings. Better drug is obtained when the propaga-tion is carried out
with fresh seeds. The plants should be protected from nematodes, fungus and
Mosaic virus.
The drug is collected mainly from wild plants. Roots and
rhizomes are dug out in October–November when the plant roots are two to four
years old. The aerial parts and roots are separated. The roots are washed and
dried in air. The roots containing moisture up to 12% should be protected from
light. Seasonal variation, genetic differences, geographic location, improper
handling and drying, and other factors account for percentage differences in
alkaloid amount. Rauwolfia should be packaged and stored in well-closed
containers in a cool, dry place that is secure against insect attack.
Characteristics
The roots and rhizomes are almost identical in external
characters. The drug occurs in cylindrical or slightly tapering, tortuous
pieces, 2–10 cm long, 5–22 mm in diameter. The roots are rarely branched.
Rootlets, 0.5–1 mm in diameter, are rare. The outer surface is greyish-yellow,
light-brown or brown. Young pieces contain slight wrinkles while old pieces
have longitudinal ridges. Circular scars of root-lets are present. Bark
exfoliation is present in old samples leaving behind patches of exposed wood.
The fracture is short. A narrow, yellowish-brown bark and a dense pale yellow
wood are present on the smooth transverse surface at both the ends. Pieces of
rhizome closely resemble the root but may be identified by a small central
pith. They are attached to them with small pieces of aerial stem. Slight odour
is felt in recently dried drug which decreases with age; taste is bitter.
Microscopy
Transverse section of the root shows a stratified cork,
which is divided, into two to eight alternating zones. It consists of one to
seven layers of smaller and radially narrower, suberised, nonlignified cells
alternating with one to three layers of larger radially broader, lignified
cells. The phelloderm is composed of about ten to twelve layers of tangentially
elongated to isodiametric, cellulosic parenchymatous cells. Cells of secondary
cortex are parenchymatous and contain starch grains, simple and compound (two
to four components), spherical with a distinct hilum in the form of a split.
Phloem is narrow and consists of parenchyma with scattered sieve tissue;
parenchyma alternate with broader medullary rays composed of large cells and
usually two to four cells wide. Xylem is wide, entirely lignified and usually
shows two to five annual rings. Medullary rays, one to five cells wide, contain
starch grains and alternate with secondary xylem consisting of vessels,
tracheids, fibres and parenchyma. Xylem vessels have pitted thickening.
Chemical Constituents
Rauwolfia contains about 0.7–2.4% total alkaloidal bases
from which more than 80 alkaloids have been isolated. The prominent alkaloids
isolated from the drug are reserpine, rescinnamine, ψ-reserpine, rescidine, raubescine and deserpidine. The other
alkaloidal components are ajmalinine, ajmaline, ajmalicine (8-yohimbine),
serpentine, serpentinine, tetrahydroreserpine, raubasine, reserpinine,
isoajamaline and yohambinine.
The other substances present are phytosterols, fatty acids,
unsaturated alcohols and sugars.
Uses
Rauwolfia in used as hypnotic, sedative and
antihypertensive. It is specific for insanity, reduces blood pressure and
cures pain due to affections of the bowels. It is given in labours to increase
uterine contractions and in certain neuropsychiatric disorders. Ajmaline, which
has pharmacological properties similar to those of quinidine, is marketed in Japan
for the treatment of cardiac arrhythmias.
Reserpine is a white or pale buff to slightly yellow,
odourless, crystalline powder that darkens slowly when exposed to light and
rapidly when in solution. Reserpine is an antihypertensive and tranquilizer. Rescinnamine
is the methyl reserpate ester of 3,4,5-trimethoxy cinnamic acid. The usual
antihypertensive dose of rescinnamine is 500 μg, two times a day. Higher doses
may cause serious mental depression. Deserpidine is 11-des-methoxyreserpine. It
is a wide-range tranquilizer and antihypertensive and is free from the side
effects.
Marketed Products
It is one of the ingredients of the preparations known as
Confido, Lukol, Serpina (Himalaya Drug Company) and Sarpagandhan bati
(Baidyanath).
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