Phytochemical screening and evaluation of analgesic activity of methanolic extract of Psidum guajava leaves in albino mice

Abstract

Introduction: Pain is an unpleasant feeling often associated with tissue damage which is well-known signal of ill health and analgesics are the drugs that are used to relieve pain. The main problem with these drugs remains that of side effects. Safer alternatives are natural herbs. Guava leaf (Psidium guajava) is one such with analgesic potential but there are few studies to suggest this fact.

Objective:To perform phytochemical screening and evaluation of analgesic activity of methanolic extract of psidium guajava leaves in Albino mice.

Materials and Methods: For this purpose, extract of Guava (Psidium guajava) leaves were collected from Gaushala area and identified by National Herberium Center Godawari, Lalitpur. The extract was prepared by Soxhlet apparatus using Methanol as solvent. Preliminary identification of phytochemical constituents was performed which showed the presence of alkaloids, glycosides, carbohydrate, saponins and flavonoids. Albino mice were divided randomly in four groups of five mice each. Group 1 (control) received NS orally, group 2 (standard) received Morphine (10mg/kg), group 3 (test) received P. guajava extract (100 mg/kg) and group 4 (test) received P. guajava extract (200 mg/kg) orally. Analgesic activity was evaluated using hot plate to determine central analgesic activity. Similarly, acetic acid induced writhing test was used to determine peripheral analgesic activity by comparing with standard drug (Paracetamol) 100mg/kg. All the observations were analyzed using % analgesia and % pain inhibition.

Observation and Results: Decrease in pain was found with percentage reduction in analgesic activity by (71.96% to 45.79%) compared to standard group with 200 mg/kg extract P. guajava leaves extract. Similarly, % reduction in analgesic activity by 35.50 % and 23.07% at 90 min and 60 min respectively with 200 mg/kg extract administered and 18.75% at 90 min with 100 mg/kg extract administered.

Conclusions: The above findings suggest that extract of Guava (P. guajava) leaves possess analgesic activity. This analgesic activity probably involves peripheral as well as central mechanisms as the extract showed analgesic activity in both hot plate and abdominal writhing method.