ABSTRACT: The traditional use of Onosma L. species as a remedy motivated scientists to discover great biological/pharmacological potentials in this plant. In the current study, in addition to the phytochemical composition of methanol (MeOH), water, and ethyl acetate extract of aerial parts of Onosma mutabilis Boiss., an endemic plant species in the flora of Kurdistan, Iraq, in vitro antioxidant, cytotoxicity, and oral toxicity activity were investigated. Results of total phenolic and total flavonoid tests show the MeOH extract superiority, and the results of Gas chromatography-mass spectrophotometer(GS/GS-MS) show 18 chemical compounds in the MeOH extract, and the majority of the detected compounds were alkaloids (78.77%) and steroids (11.48%), namely as 5,8-dihydroxy-2-(4-methylpent-3-enyl) naphthalene-1,4-dione (48.60%), 3-O-Methyl-d-glucose (27.49%), β-Sitosterol (6.81%), Phenol, 2,4-bis (1,1-dimethyl ethyl)-, phosphite (3.46%), and 24,25-Dihydroxycholecalciferol (3.14%). Results of the antioxidant tests show the MeOH extract superiority in the phosphomolybdenum assay, radical scavenging [on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)] assays, and reducing power [cupric reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP)] assays (1.45, 3.54, 2.33, 1.12, 1.62, mg/ml, respectively). The cytotoxicity results of the plant extract are presented as IC50 (inhibitory concentration at 50%) on the prostate cancer cells (DU-145), mammary cancer cells (MCF-7), and human cervix carcinoma (Hep2c), at which values ranged from 28.79 to 41.83 μg/ml. Results of the acute toxicity in the dose-dependent trail (100, 200, 300, 600 mg/kg of MeOH) show the absence of the behavior and appearance changes of female Wister rats. Overall, O. mutabilis extract exhibited significant natural potentials probably because of its polar phytochemicals, which could be an alternative source for remedial, nutrient, and cosmetic manufacture.
