Abstract:
Thonningia sanguinea is one of the herbal preparations vised prophylactieally
against asthma at the Centre for Scientific Research into
Plant Medicine. Preparations of this plant are used with Desmodium
adseendens which has been shown to be anti-anaphylactic. The anaphylactic
reaction is a basic underlying phenomenon in asthma. In this
work, the effects of T. eanguinea preparations were evaluated on some
aspects of the disease.
The method adopted was experimental anaphylaxis in the guinea pig.
Both _in vivo and in vitro assay systems were used to evaluate extracts
prepared from the plant material.
The results showed that the plant material when administered orally
(i) inhibited anaphylactic contractions in ileal pieces ( p < 0.05)*
(ii) acted to reduce the sensitivity of ileal pieces to histamine
(p < 0.05),
(iii) inhibited the anaphylactic release of histamine from lung
tissues (p < 0.05),
(iv) reduced the amount (or effect) of mepyramine-resistant spasmogens
released anaphylactically from lung tissues (p<0.05), and
(v) reduced the total histamine content of lung tissues (p<0.05). The crude extract, and some of its fractions, when assayed
in vitro, inhibited the anaphylactic contractions in the ileal pieces
in much the same way as when the aqueous extract was administered orally
(p<0.05). However, tfae ' iLn vitro effects on histaraine-induced contractions
differed from the effect observed when the crude extract was
administered orally. Since Thonningia preparations are administered
orally, the in vitro assay system involving histamine-induced contractions,
was considered to be of little or no use in evaluating the anti-asthmatic
effect of the plant.
These results are discussed with respect to the possible ways by
which the plant could interfere with anaphylaxis and thereby prevent the
incidence of asthmatic attacks. The results suggested a similar mechanism
of action for both Thonningia and Desmodium.
Qualitative analysis indicated the presence of enolic and/or phenolic
steroids. The densitometer scan as well as Rf values and colours of resolved
components could be used to control and standardize the quality
of Thonningia preparations for future use.
