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Bacopa monniera (Brahmi, whole plant, Scrophulariaceae) and Alstonia scholaris (Chhatim, leaves and bark, Apocynaceae) were evaluated for broncho and vasodilatory activities. The ethanol extract of B. monniera (50 mg/kg) and A. scholaris (leaves, 25 mg/kg) produced significant inhibition (100 + 0%) of carbachol (1X10-5 M/kg) induced bronchoconstriction in anaesthetized rats, suggesting the presence of bronchodilatory activity. These results were further strengthened by in vitro experiments where the ethanol extract of B. monniera (200-700 ug/ml) produced 21-77 and 12-57% relaxation of guinea-pig tracheal preparations contracted by histamine and potassium chloride, respectively. One the contrary A. scholaris failed to produce such effects. In anaesthetized rats the bronchodilatory activity of B. monniera was attenuated (about 70%) in the presence of indomethacin (3 mg/kg). Likewise, extract-induced relaxation (48%) was also completely inhibited by indomethacin (1X10-7 M) implying that bronchodilation in vive and in vitro systems is mediated via prostaglandins. Additionally, extract-induced relaxation of tracheal preparations was partially (about 40%) antagonized by propranolol suggesting the participation of B-adrenoceptors. Noticeabel reduction (98 + 2%) in calcium chloride-induced contractures were also obtained that is indicative of calcium antagonism through voltage-operated calcium channels. However, retardation of calcium ions from intracellular stores cannot be ignored. Thus it appears that the bronchodilatory property residing in B. monniera is governed by multiple mechanisms The ethanol extract and various fractions derived from B. monniera and ethanol extract of A. scholaris also cased significant diminution of carbachol-induced hypotension and bradycardiac effects in anaesthetized of carbachol-induced hypotension and bradycardiac effects in anaesthetized rats. This was also reflected by vasorelaxant effect produced by B. monniera on pulmonary artery (guinea-pit, 32-84% and rabbit, 33-90%) and aorta (rabbit, 21-61%) in a dose-dependent manner. It appears that the vasorelaxant action of B. monniera was equally contributed by prostaglandin (s), B adrenoceptors and calcium immobilization through both receptor and voltage-operated calcium channels. Furthermore, in pulmonary artery the calcium release from intracellulary stores was also impeded marginally by the extract. In in vivo system the bronchodilatory activity of B. monniera increased 1087X in pure compound (betulinic acid) whereas, in in vitro system the broncho and vasodilatory activities either remained unchanged or increased about 2-folds in fractions. In subsequent sub fractions and sub-sub fractions both the activities were negligible, however, betulinic acid demonstrated moderate activities. The ethanol extract of A. scholaris also exhibited dose-dependent relaxation (5-86%) on guinea-pig pulmonary artery which was substantially inhibited (96 +2%) after pretreatment with L-arginine methyl ester (1X10-3 M), indicating a noticeable role displayed by endothelium-derived relaxing factor(s) and to some extent that of calcium-antagonism The ethanol extract and various fractions of B. monniera and A. scholaris extract also produced spasmolytic activity on gut tissues (ileum and jejunum) mainly via Ca2+ antagonism. Unlike, broncho-vasodilatory activity, the spasmolytic activity of B. monniera extract was increased about 2-folds after processing the fractions to afford sub-fractions It was revealed that ethanol extract, ethyl acetate and methanol fractions of B. monniera also possess anti-inflammatory activity in rodents. The B. monniera extract produced anti-inflammatory activity via inhibition of prostaglandin (E2)-induced oedema. This activity was absent in A. scholaris extract In conclusion, the present study demonstrated that B. monniera and A. scholaris possess broncho-vasodilatory and anti-inflammatory activities via interfering with calcium mobilization, B-adrenoceptors, endothelium-derived relaxing factor(s) and prostaglandin(s), hence providing a basis to develop effective agents respiratory and cardiovascular diseases

Item Type:Thesis (PhD)
Uncontrolled Keywords:broncho-vasodilatory activity, alstonia scholaris, bacopa monniera, anti-inflammatory activity, vasorelaxant action, ethanol extract, ethyl acetate, methanol fractions, calcium mobilization, b-adrenoceptors, endothelium-derived relaxing factor, prostaglandin
Subjects:Physical Sciences (f) > Chemistry(f2)
ID Code:1085
Deposited By:Mr. Muhammad Asif
Deposited On:19 Feb 2007
Last Modified:04 Oct 2007 21:04

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