Agriculture Reference
In-Depth Information
Synonyms —
Cryptolepis triangularis
N.E. Br.,
Pergularia sanguinolenta
Lindl.,
Strophanthus
radcliffei
S. Moore
Family —
Apocynaceae
Common Names —
Yellow dye root, Ghana quinine, nimbima
African Names —
Bambara: ouidoukoi; Dioule: nombon; Fulani: delboi; Hausa: gangamau;
Mende: kpokpo-yangolei, shona mukangaza (
C. oblongifolia
)
Description —
The plant is a twining, scrambling shrub, with characteristic thin stems
and tuberous rootstock. The leaves are opposite, thinly herbaceous, elliptic oblong to ovate or
lanceolate in shape. The margin is entire; the apex is curved and acuminate, and the base is
symmetrical and obtuse or rounded. The midrib projects prominently on the lower side and is
pinnately nerved. The dried leaves have a slightly bitter taste. The roots are rather tortuous and
branched with little or no rootlets, with longitudinal ridges apparent in the dried samples. The
root is distinctly yellow in color and breaks with a short fracture exposing a smooth transverse
surface, which is yellow in color.
347
Habitat and Distribution —
The plant grows in the rainforest and deciduous forest belt. It
is distributed throughout the West Coast of Africa. Related species occur in eastern and southern
regions of the continent.
Ethnomedicinal Uses —
The main use of the root of
Cryptolepis
is in the treatment of fevers.
Extracts of the plant have also been employed for the treatment of urogenital infections, especially
Candida
infections of nonvenereal origin.
348
In southern Nigeria, a weak decoction of the root is
administered as a tonic and for the treatment of anti-inflammatory conditions. The plant appears to
be used as an ingredient in several folk remedies for a multiplicity of diseases, but the major uses
are in the preparation of remedies for the treatment of malaria, hypertension, microbial infections,
and anti-inflammatory conditions.
Constituents —
The principal constituent is the quindoline alkaloid cryptolepine, which occurs
at a yield of 0.52% w/w in the roots, 0.48% in the stem, and 1.03% in the leaves.
347
The compound
co-occurs with the related bases and their derivatives.
Pharmacological Studies —
The aqueous extract and the isolate cryptolepine have been shown
to possess significant inhibitory activity against some bacteria and yeasts.
349,350
The alkaloid has
also been found to inhibit carrageenan-induced edema of the rat hind paw in a dose-dependent man-
ner. The activity was shown to be less potent than that of aspirin or indomethacin. The
in vitro
stud-
ies showed 1-20 µg/ml of cryptolepine did not inhibit prostaglandin synthesis in the isolated lizard
lung, but it antagonized the effects of E2 prostaglandin and did not affect that of 5-hydrotryptamine
on a perfused isolated stomach strip of the rat. The compound also antagonized the action of his-
tamine and of acetylcholine on the isolated guinea pig ileum.
351,352
The biological activity of the
compound may be due to its demonstrated adrenoreceptor blockage activities.
352,353
Cryptolepine
also possesses hypotensive
354
and vasodilatory activities.
354,355
Clinical studies have shown that extracts of the roots produced antimalarial cures in patients
with the concomitant elimination of parasitemia in the blood.
356
The extract also showed antipyretic
activity in the patients evaluated. Several modifications have been made on the structure of the natu-
rally occurring antiplasmodial compound cryptolepine, which have resulted in remarkable improve-
ment in the antimalarial activity. Cryptolepine derivatives containing alkyldiamine side chains also
possess potent inhibitory activity against
Trypanosoma brucei brucei
. These derivatives are also
potent inhibitors of the trypanosome papain-like cysteine protease cruzain, which could, at least in
part, explain their antitrypanosomal activity. Such compounds with good antitrypanosomal activity
and selectivity provide an encouraging starting point for the rational design of new and effective
antitrypanosomal agents.
483
Cryptolepis
alkaloids and their semisynthetic derivatives are subjects of ongoing studies to eval-
uate their antiprotozoal, antidiabetic, analgesic, anti-inflammatory, and antituberculosis activities.
