Evaluation of antinociceptive activity of aqueous extract of bark of psidium guajava in albino rats and albino mice.

BACKGROUND Psidium guajava is commonly known as guava. Psidium guajava is a medium sized tree belonging to the family Myrtaceae found throughout the tropics. All the parts of the plant, the leaves, followed by the fruits, bark and the roots are used in traditional medicine. The traditional uses of the plant are Antidiarrheal, Antimicrobial Activity, Antimalarial/Antiparasitic Activity, Antitussive and antihyperglycaemic. Leaves are used as Anti-inflammatory, Analgesic and Antinociceptive effects. AIM To evaluate the antinociceptive activity of aqueous extract of bark of Psidium guajava in albino rats with that of control and standard analgesic drugs aspirin and tramadol. MATERIALS AND METHODS Mechanical (Tail clip method) and thermal (Tail flick method using Analgesiometer), 0.6% solution of acetic acid writhing models of nociception were used to evaluate the extract antinociceptive activity. Six groups of animals, each consists of 10 animals, first one as control, second and third as standard drugs, Aspirin and Tramadol, fourth, fifth and sixth groups as text received the extract (100, 200, and 400 mg/ kg) orally 60 min prior to subjection to the respective test. RESULTS The results obtained demonstrated that aqueous extract of bark of Psidium guajava produced significant antinociceptive response in all the mechanical and thermal-induced nociception models. CONCLUSION AEPG antinociceptive activity involves activation of the peripheral and central mechanisms.