TNF-α inhibitory effect of Euphorbia hirta in rats

Euphorbia hirta L. (Euphorbiaceae) (E. hirta) is a tree locally used as a traditional medicine in Africa and Australia to treat numerous diseases such as hypertension, respiratory ailments, tumors, and wounds, and it has reported antiallergic, antipyretic, anti-inflammatory activities, etc.

This study evaluated the ability of fresh leaves of E. hirta ethanol extract to inhibit the intracellular tumor necrosis factor α (TNF-α) level in the synovial fluid and neutrophils in lipopolysaccharide (LPS)-induced inflamed rat knees.

Female Wister albino rats 140-160 g were used. E. hirta ethanol extract was given orally at 25, 50, 100, and 200 mg/kg, 2 h before an intra-articular (i.a.) injection of LPS. Two and three hours later, synovial fluid and neutrophils levels of intracellular TNF-α production were measured.

In the time course of the experiment, E. hirta maximum inhibition at 100 and 200 mg/kg (p.o.) dose showed 16.5 ± 1.34 and 14.4 ± 1.30% of synovial fluid, 4.26 ± 0.36 and 3.78 ± 0.29% of neutrophils levels of intracellular TNF-α productions at 2 h after LPS injection. LPS control displayed 22.97 ± 1.61 and 6.78 ± 0.34% of synovial fluid and neutrophils levels of intracellular TNF-α at 2 h after LPS injection. Intracellular TNF-α was also estimated at 3 h after LPS injection.

The LPS-injected rat knee model gives a comparative study of acute anti-inflammatory responses. E. hirta inhibition of proinflammatory intracellular cytokine TNF-α production with LPS-induced inflamed rat knee is of great importance in defining the anti-arthritic potential of E. hirta.