Effect of Calotropis procera extract against Eimeria piriformis oocyst- and sporozoite-infected rabbits.

Purpose: To investigate the effect of Calotropis procera (Asclepiadaceae) extract on Eimeria piriformis (E. piriformis) oocysts and sporozoites (coccidiosis) isolated from commercial rabbits. Methods: Calotropis procera extract was obtained from dried, pulverized leaves, and macerated in 80 % methanol for 30 h. The extract was analyzed using infrared spectroscopy (IR). Twelve-well plates of 3 mL containing 1 x 104 non-sporulated oocyst were tested in 6 groups: Negative (untreated) control received 2.5 % potassium dichromate solution. Other groups received four concentrations of C. procera leaf extract (12.5, 25, 50, and 100 mg/mL) for oocysts vitality test. Toltrazuril (25 µl/mL) was used as positive control. Moreover, 250, 500, 750, and 1000 µg/mL of C. procera extract were tested for sporozoites vitality test. The mixture was examined daily for 4 days for oocysts vitality and after 12 and 24 h for sporozoite vitality. Results: Findings of IR showed that extracts contained 5 biologically active chemical components, indicating the presence of alkaloids, flavonoids, saponins, and phenols. The extract showed a significant inhibitory effect on E. piriformis oocysts at 100 mg/mL with suppression rates of approximately 89 % after 96 h, nearly similar to toltrazuril (p ≤ 0.01). Furthermore, C. procera extract showed inhibition at the highest repression (p ≤ 0.01) of 89 % of E. piriformis sporozoites viability at 1000 µg/mL after 24 h. The inhibitory rate increased proportionately with an extended incubation duration and high concentration. Conclusion: C. procera extract is as effective as the positive control in treating coccidiosis in rabbits. However, further studies are necessary to determine the active constituents of C. procera and their mode(s) of action. [ABSTRACT FROM AUTHOR]