摘要：Acacia nilotica (L) related to (family Fabaceae-Mimosoideae). The division is Magnolophyta and class is Magnolipsida. The genus is Acacia and species is nilotica. The ailments treated by this plant include colds, congestion, fever, gallbladder, hemorrhage, hemorrhoids, leucorrhoea, ophthalmic, sclerosis and small pox. Acacia bark is drunk for intestinal pains and used for treating acute diarrhea. Other preparations are used for gargle, toothache, ophthalmic and syphilitic ulcers. The roots of Acacia are used to treat tuberculosis. This study was carried out to evaluate antigiardial activity (Giardia lamblia), antioxidant (DPPH assay) and cytotoxicity (MTT assay) of ethanol extract of A. nilotica (leaves). The ethanol extracts of A. nilotica (leaves) was screened for its antigiardial activities (Giardia lamblia), antioxidant screening for their free radical scavenging properties using 2.2Di (4-tert-octylphenyl)-1-picryl-hydrazyl (DPPH), while propyl gallate was used as standard antioxidant and screened for their cytotoxicity using 3-(4, 5-dimethyl thiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT), was obtained from A. nilotica (leaves) ethanol extract which exhibited 100% mortality within 96 h, at a concentration 500 µg/ml; this was compared with Metronidazole which gave 96% inhibition at concentration 312.5 µg/ml at the same time. The tested antioxidant activity gave (65 ± 0.04 RSA%) in comparison to the control of propyl gallate levels (88 ± 0.07RSA%), and MTT assay verified the safety of the examined extract. In conclusion: These studies conducted for both A. nilotica (leaves) was proved to have potent activities against Giardia lamblia trophozoites in vitro. Keywords: In vitro, antigiardial activity, Giardia lamblia, Metronidazole, antioxidant activity (DPPH), cytotoxicity activity (MTT-assay), Acacia nilotica leaves, Sudan.
