Anti-inflammatory effect of Heliotropium indicum Linn on lipopolysaccharide-induced uveitis in New Zealand white rabbits

AIM： To investigate the anti-inflammatory effect of an aqueous whole plant extract of Heliotropium indicum（HIE） on endotoxin-induced uveitis in New Zealand white rabbits.·METHODS： Clinical signs of uveitis including flares,iris hyperemia and miosis, were sought for and scored in1.0 mg/kg lipopolysaccharide（LPS）-induced uveitic rabbits treated orally with HIE（30-300 mg/kg）,prednisolone（30 mg/kg）, or normal saline（10 m L/kg）. The number of polymorphonuclear neutrophils infiltrating, the protein concentration, as well as levels of tumor necrosis factor-α（TNF-α）, prostaglandin E2（PGE2）, and monocyte chemmoattrant protein-1（MCP-1） in the aqueous humor after the various treatments were also determined. A histopathological study of the anterior uveal was performed.· RESULTS： The extract and prednisolone-treatment significantly reduced（P ≤0.001） both the clinical scores of inflammation（1.0-1.8 compared to 4.40 ±0.40 in the normal saline-treated rabbits） and inflammatory cells infiltration. The level of protein, and the concentrationsof TNF-α, PGE2 and MCP-1 in the aqueous humor were also significantly reduced（P ≤0.001）. Histopathological studies showed normal uveal morphology in the HIE and prednisolone-treated rabbits while normal saline-treated rabbits showed marked infiltration of inflammatory cells.· CONCLUSION： The HIE exhibits anti-inflammatory effect on LPS-induced uveitis possibly by reducing the production of pro-inflammatory mediators.

Effect of pre-existing Schistosoma haematobium infection on Plasmodium berghei multiplications in imprinting control region mice

Objective: To investigate the effect of pre-existing Schistosoma haematobium(S. haematobium) infection on malaria disease severity.Methods: The study involved the use of twenty-i ve imprinting control region mice, i fteen of which were initially infected with S. haematobium. Five of the remaining ten schistouninfected mice together with i ve schisto-infected mice were infected with Plasmodium berghei(P. berghei) after four weeks(acute stage) of schistosoma infection. The remaining i ve schisto-uninfected mice together with i ve schisto-infected mice were also infected with P. berghei after seven weeks(chronic stage) of schistosoma infection. The last i ve schistoinfected mice were used as control group. They were then monitored for changes in P. berghei parasitaemia on Days 3, 5, 7, 9 and 11 post-infection. Records on their survivability were also taken.Results: The co-infected mice had signii cantly higher malaria parasitaemia, compared with the mono-infected mice during acute S. haematobium infection. In contrast, the co-infected mice had signii cantly lower malaria parasitaemia during chronic S. haematobium infection and a higher survival rate.Conclusions: Co-infection of mice with P. berghei during acute S. haematobium infection resulted in rapid P. berghei development and increased malaria parasitaemia. However, the co-infection resulted in slower P. berghei development and decreased malaria parasitaemia with enhanced survivability of the mice during chronic S. haematobium infection. Therefore, pre-existing chronic S. haematobium infection may provide some protection to the host by reducing parasitaemia.

In vivo antiplasmodial and in vitro antioxidant property of stem bark extracts of Haematostaphis barteri

Objective: To evaluate the antimalarial and antioxidant properties of stem bark extracts of Haematostaphis barteri(H. barteri).Methods: The prophylactic activity of the plant was performed by dosing mice with sulfadoxine-pyrimethamine(1.2 mg/kg), aqueous extract(30, 100, 300 mg/kg) and dichloromethane/methanol(D/M)(30, 100, 300 mg/kg) extracts of H. barteri for 3 days. On the 4th day, the mice were inoculated with Plasmodium berghei. The parasite density was estimated for each mouse 72 h post-parasite inoculation. The curative activity of the plant was also performed by inoculating mice with Plasmodium berghei. Three days later, they were treated with artemether-lumefantrine(4 mg/kg), aqueous and D/M extracts of H. barteri stem bark for 5 days. The in vitro antioxidant property of the aqueous extract was determined by using the reducing power, nitric oxide and total antioxidant capacity assays. Results: The aqueous extract exerted significant(P < 0.05) curative and prophylactic antimalarial activities. The D/M extract exhibited significant curative(P < 0.05) but not prophylactic antiplasmodial ef ect. The aqueous extract exhibited in vitro antioxidant property with IC50's of(0.930 ± 0.021) mg/mL,(0.800 ± 0.001) mg/mL and(0.22 ± 0.05) mg/mL in the total antioxidant capacity, reducing power and nitric oxide assays. Histological assessment of the liver of aqueous and D/M treated animals did not reveal any sign of toxicity.Conclusions: H. barteri is not toxic which exerted significant curative antiplasmodial ef ects but the prophylactic property was however fraction dependent. The mechanism of the antiplasmodial activity of H. barteri may partly be mediated by its antioxidant property.