Sub-Acute Anti-Inflammatory Activity of Leucas indica Ethanolic Leaf Extract in Wistar Rats Using the Cotton Pellet Granuloma Model

This study investigated the sub-acute anti-inflammatory potential of Leucas indica leaves using the cotton pellet granuloma model in Wistar albino rats. Fifty rats were randomly assigned to five groups (n = 10 per group). Sterile cotton pellets (~20 ± 1 mg) were prepared and autoclaved before subcutaneous implantation at the nape of the neck following sedation with pentobarbitone sodium (30 mg/kg, orally) and skin disinfection with 70% ethanol. Treatment regimens included: a control group receiving 3 mL of 1% gum acacia (orally), a standard group administered Indomethacin (10 mg/kg, orally), and three test groups receiving leaves of Leucas indica ethanolic extract at 75, 150, and 300 mg/kg, three times daily for seven days. On the eighth day, the animals were humanely sacrificed, and the implanted pellets were removed, dried, and weighed to assess inflammatory response. Key parameters, including granuloma formation, transudative weight, and percentage inhibition, were analysed using ANOVA with Dunnett’s multiple comparison test (p < 0.05 considered significant). Standard drug (Indomethacin) produced a highly significant reduction (p<0.01) in all three parameters (WW, DW, TW), confirming the model's validity and the drug’s strong anti-inflammatory effect. EELLI at 75 mg/kg showed no statistically significant reduction, indicating weak or no anti-inflammatory activity at this dose. EELLI at 150 mg/kg and 300 mg/ kg showed a significant reduction in: Wet weight (WW): Suggests decreased exudation and inflammation. Dry weight (DW): Indicates reduced granuloma formation (proliferative phase). Transudative weight (TW): Reflects reduced fluid accumulation. The ethanolic extract of Leucas indica (EELLI) exhibited significant sub-acute anti-inflammatory activity at 150 mg/kg and 300 mg/kg, as evidenced by reduced granuloma weight and fluid accumulation. The effect, though moderate compared to Indomethacin, supports the plant’s traditional use and warrants further investigation.