Evaluation of Hypotensive and Vasodilatory Effects of Murraya koenigii Leaves Extract in L-NAME Induced Hypertensive Rats in Relation with Muscarinic Receptors

Background High Blood Pressure (BP) is a dreadful condition worldwide. Available scientific data confirms the antihypertensive potential of traditional plants. Present study was aimed to assess the blood pressure lowering effect of hexane (MURK-HEX), ethyl acetate (MURK-EA) and methanol (MURK-MeOH) extracts of Murraya koenigii leaves in L-NAME induced hypertensive rats with possible mechanism of action. Materials and Methods Air dried leaves of " Murraya koenigii" were extracted with different organic solvents namely methanol (MURK-MeOH), Hexane (MURK-HEX) and ethyl acetate (MURK-EA). Wistar rats of either sex were used in the study. Hypertension was developed by L-NAME and then data was collected after jugular vein cannulation using Oscillograph and powerlab data acquisition system. For possible mode of action muscarinic pathway was chosen. Data was analysed using SPSS-20 by applying independent sample t-test. Results and Discussion The invasive method revealed that "MURK-HEX", "MURK- EA" and "MURK- MeOH" extracts exhibited significant dose dependent (18.8-50.1) % fall in MABP at the log doses (1,3, 5, 10 and 30 mg/kg) in normotensive rats. Except, "MURK-HEX", the "MURK-EA" and "MURK-MeOH" altered the BP lowering effect, when these extracts followed by "Atropine" (Atr 10-4M) via intravenous route. Results demonstrate that MURK- EA and MURK-MeOH showed the involvement of muscarinic receptors while hypotensive effect of MURK-HEX may mediate via another pathway. In L-NAME induced hypertensive rats, MURK-HEX, MURK- EA and MURK- MeOH exhibited an immediate (18.37-51.93% falls) in MABP but it did not persist for longer time. Conclusion Murraya koenigii caused a significant decrease in MABP by the stimulation of muscarinic receptor in activation of EDRF which release nitric oxide to produce vasorelaxation.