Results: Two doses of HNT (HNT1, 50 mg / kg and HNT2, 100 mg / kg, p o x 14 days) prove the protective role in learning and memory impairments caused by TMT one dose exposure (2.4 mg / kg, i. p) by evaluation of MWM: Hidden Platform Test (p < 0.001 as compared between TMT and HNT1 + TMT or HNT2 + TMT group); Probe Test (p < 0.01 as compared between TMT and HNT1 +TMT or HNT2 +TMT group); and Working Memory Test (p < 0.05 as compared between TMT and HNT1 + TMT; p < 0.01 as compared between TMT and HNT2 + TMT).