Pharmacognostical Profile of Selected Medicinal Plants - African Medicinal Plants - page 312

African Name — Yoruba: ewe aran
Description — Spigelia anthelmia is a small, erect herb that grows up to 80 cm in height; the
stem is smooth and rounded. The leaves occur in whorls, usually 4 in number at the end of the stem
or branch. They are oval in shape, elongated, up to 15 cm long and about 7.5 cm broad. They are
almost transparent and without stalks. The flowers are pale pink in color and with dark stripes,
about 1.3 cm long. The calyx has 5 pointed lobes with narrow segments and a funnel-shaped corolla,
which also has 5 small lobes. There are 5 stamens attached to the corolla tube. The style is single.
The fruits are small, round, warty, and two lobed. 77
Habitat and Distribution — Spigelia anthelmia is a native of tropical and subtropical America
but is widely naturalized in tropical Africa and Indonesia. It occurs in Africa as a common weed in
abandoned farmlands, in deciduous forests, and semisavanna. It is distributed from Senegal to the
Congo and as far east as Ethiopia.
Ethnomedicinal Uses — All parts of the plant are used as an anthelminthic. The method of
preparation differs according to the locality. In many cases, medication is followed within 12 h by
administration of a purgative or enema. The fresh leaves are believed to be poisonous to domestic
animals, being able to cause their death in 2 to 3 h. High doses of the plant extract are very toxic,
and fatalities in adults have been reported with very high doses.
Constituents — The major constituents of Spigelia are quaternary alkaloids, the principle ones
being spiganthine, ryanodine, and structurally related compounds. The highest concentrations of alka-
loids are present in the roots and in the fruit wall. Spiganthine and ryanodine are the main cardioac-
tive principles. The plant also contains ditepenes. A detailed phytochemical study of the aerial parts
yielded derivatives of the known cardiotonic compounds spiganthine and ryanodine, 20-deoxyspigan-
thine, 8α-hydroxyspiganthine, 20-norspiganthine-5-carboxylic acid, 10- epi -ryanodine, 8,9-dehydro-
10- epi -ryanodine, and 20-hydroxyryanodine. 983
Pharmacological Studies — Spigelia is used in alternative medicine in Europe as a cardiotonic.
The constituents have cardioactivity and insect antifeedant activity. It has anthelmintic properties. The
ethyl acetate extract induces tonic paralysis in vivo, decreases amplitudes of twitches, and increases
tonus of skeletal muscle in vitro in laboratory animals. 984 It was reported that an ethyl acetate extract of
Spigelia anthelmia with validated anthelmintic activity was evaluated for its acute toxicity and general
effects in albino Swiss mice and for neuromuscular relaxant activity in the frog sciatic-gastrocnemius
and rectus abdominis preparation. The extract induced a dose-related myotonia and muscular paralysis of
rapid onset at higher doses. The calculated LD 50 after oral and intraperitoneal administration were 345.9
(241.4-484.7) mg/kg and 60.8 (47.4-80) mg/kg, respectively. In broilers, intramuscular injection of the
extract induced spastic paralysis qualitatively similar to that obtained after succinylcholine administra-
tion and contrasting to the flaccid paralysis induced by d-tubocurarine. The contraction elicited by direct
stimulation of the gastrocnemius was blocked by the extract, and the twitches evoked by stimulation of
the sciatic nerve were also blocked. It did not decrease tonic contractions induced by a high-potassium
Ringer solution but blocked acetylcholine-induced contractions in the frog rectus abdominis. 984
STEPHANIA ABYSSINICA
Botanical Name — Stephania abyssinica Dill & Rich.
Synonym — S. abyssinica Wa lp.
Family — Menispermaceae
African Names — Chagga: mkwamabewa; Yoruba: gbejedi; Zulu: umthombo, umtambane
Description — Stephania abyssinica is a slender glabrous liane growing up to 12 m high. The
leaves, 5-7 cm, are dark green at the upper surface and glaucous underneath.
Habitat and Distribution — The plant grows the tropical regions of the continent, preferring
rainforest areas. It occurs from Sierra Leone to Gabon and from Zaire to Botswana.