FIG. 4.

Curcumin (C) protects against paraquat (PQ)-induced mobility defects in 4- to 5-day-old flies under co-treatment and pre-treatment regimes as tested in a negative geotaxis assay. The distance a male fly climbs in 12 sec after 24 hr (A) and 48 hr (B) of exposure to 10 mM PQ or 10 mM PQ with different concentrations of curcumin was assayed. Feeding of curcumin alone showed no effect on speed of the fly, whereas ingestion of PQ alone adversely affected mobility. PQ and C co-feeding resulted in significant improvement in mobility performance. In the pre-treatment regime, curcumin protects against PQ-induced mobility defects after 24 hr (C) and 48 hr (D) in a negative geotaxis assay, suggesting that the rescue effect of curcumin is not due to antagonistic interaction with PQ (one-way analysis of variance [ANOVA] followed by Newman–Keuls multiple comparison test showed that the protective efficacy of curcumin in the co-treatment regime is highly significant compared to the PQ-treated group). (***) p<0.0001.