The present study was carried out to shed light on the chemical analysis of Glycyrrhiza glabra for different active compounds, and on the cytogenetic effects of methotrexate(MTX) and aqueous extract of G. glabra in laboratory mice (in vivo) and human blood lymphocytes (in vitro). The study also aimed to investigate the role of G. glabra aqueous extract in reducing the cytogenetic effects of MTX in mouse through the parameters mitotic index, and chromosomal aberration in bone marrow, the total and differential counts of leukocytes, and sperm head and tail morphology. The cytogenetic analyses were extended to include blast index, mitotic index, replicative index, sister chromatid exchanges and chromosomal aberrations in human blood lymphocytes in vitro as a result of G. glabra aqueous extract and MTX treatment. the cytogenetic effects of the drug and plant extract were investigated after five days of treatment in mice with three doses for each. For MTX, the doses were 1.2, 1.6, and 2 mg/kg, while the doses of G. glabra were 400, 600, and 800 mg/kg. Using human blood lymphocyte (72hour) culture, the tested concentrations of MTX were 0.4, 2, and 4 µg/ml, and for G. glabra aqueous extract were 50, 100, and 200 µg/ml. An interaction between plant extract and MTX was carried out through two types of treatments (before, and after MTX treatment) to determine the activity of G. glabra aqueous extract in reducing the drug side effects in vivo.
