Preliminary Investigations of the Anti-asthmatic Properties of the Aqueous Extract of Justicia pectoralis (Fresh Cut).

Justicia pectoralis (fresh cut plant), family Acantheceae, is a herb that is native to central America and the Caribbean. A crude extract prepared from the leaves of Justicia pectoralis is commonly used in Jamaican ethnotraditional medicine to reduce difficulty in breathing and suppress wheezing in asthmatic individuals.To investigate the anti-inflammatory and antihistamine activity of an aqueous extract of Justicia pectoralis.In in vivo experiments, guinea pigs were sensitized by the method of Weinrich and Undem (1987). The effect of water on the wheals was assessed in the control group, n = 4. The effect of 3.3 mg of the crude extract was noted in histamine-induced wheals over a period of three hours. The extract was injected via intraperitoneal injections. In in vitro experiments, 3.3 mg of crude sample was tested for its effectiveness against histamine-induced tracheal contraction caused by cumulative dosing of histamine.The crude extract was efficacious in reducing the formation of histamine-induced wheals (p < 0.05). Results obtained from in vitro studies indicated that the crude extract (3.3 mg) caused significant reduction in tracheal smooth muscle contraction resulting from cumulative doses of histamine (p < 0.05). However, as the histamine doses increased, fresh cut extract was not able to maintain inhibition of histamine-induced tracheal smooth muscle contraction. This is an indication that the extract showed competitive reversible antagonism, possibly at histamine receptors.A crude extract of the leaves Justicia pectoralis reduced the formation of histamine-induced wheals in sensitized guinea pigs (p < 0.05) and also reduced histamine-induced tracheal smooth muscle contractions (p < 0.05). It blocked the effect of contraction produced by histamine in the airways; this property supports folklore claims for its use as an antihistamine.