Page 201 - Pharmacognosy 2 PG303

Pharmacognosy-2 (PG303) Level 2 Clinical Pharmacy-Pharm D

Uses
Rauwolfia has been used in India for the treatment of insomnia and certain
forms of insanity. It produces a fall in blood pressure and has a depressant action
upon the nervous system. It is often administered in the form of powder in doses
of I-2 g.

Substitutes and Adulterants
The roots and rhizomes of other species of Rauwolfia have been collected
and substituted for the genuine drug. The most important of these is R. canescens
L.; this root is darker in color, being brownish-yellow and is further distinguished
by the absence of a stratified cork and by the presence of stone cells in the cortex
and phloem; it contains reserpine and is used for its extraction. Three other
species, viz.: R. micrantha Hook. f, R. densiflora Benth., and R. perakensis King
and Gamble, have also occurred as substitutes; all of these are darker in color than
the genuine drug; they all have a stratified cork, but they contain stone cells, of
these three R. micrantha contains reserpine. African Rauwolfia, consists of the
roots and rhizomes of R. vomitoria Afz., a plant common in tropical Africa. Its
structure is very similar to that of R. serpentina, but there is a large proporation
of sclereids in the phloem, pericycle and phelloderm. It is used commercially for
the extraction of reserpine, of which it contains about 2.0 %.

158