Quantification of Antinociceptive and Anti-inflammatory Potentials of Different Ocimum gratissimum Linn. Leaf Extracts in Male Whistar Albino Rats

Aim: This study was aimed at quantifying the antinociceptive and anti-inflammatory potency and efficacy of aqueous (AQ) and ethanolic leaf extracts of O. gratissimum (ET) in Whistar rats.

Methodology: Inflammation (paw edema) was induced in rats (n=5 per group) with fresh egg albumin (0.1 ml); groups for anti-inflammatory experiment were pretreated (0.5 h), while those for anti-nociceptive experiment were post-treated (2.5 h) with AQ (200, 400 or 800 mg/kg, p.o.), ET (200, 400 or 800 mg/kg, p.o.), piroxicam (20 mg/kg, i.p.), or normal saline (1 mL/kg, i.p.). Paw sizes of anti-inflammatory group rats were measured at 0 and 2 h after injection of phlogistic agent using plethysmometer, whereas mechanical nociceptive thresholds were measured in anti-nociceptive group rats before and 2 h after test agent treatments using analgesymeter.

Results: There was neither change in inflammatory reaction (after egg albumin injection at time 0 or 2 h) nor threshold in control rats before or after normal saline treatment. AQ inhibited (P = .05) paw edema at 400 mg/kg (26%) and 800 mg/kg (64%); whereas all three doses of ET caused inhibitions (35, 39 and 32%, respectively) compared to the egg albumin induced values. AQ and ET treatments increased (P = .05) mechanical nociceptive thresholds, but maximum effects were observed at 400 mg/kg for both extracts (144 and 270%, respectively) compared to values obtained before extract treatment. Piroxicam produced significant inhibitions in inflammation (20%) and nociception (100%).

Conclusion: ET is more potent, but AQ is about twice as efficacious as ET in anti-inflammatory activity. Also, ET is more potent and has a higher analgesic efficacy than AQ.