Cytogenetic toxicity of neem.

The cytogenetic toxicity of the leaf extract of neem was evaluated in murine germ cells. The extract was found to induce structural and numerical changes in the spermatocyte chromosomes as well as synaptic disturbances in them at their first metaphase. A significant increase in the frequency of sperms with abnormal head morphology and the decrease in mean sperm count were also observed. This spermatotoxic effect of the neem extract corroborates its germ cell mutagenicity. The possible role of azadirachtin, the most active principle present in the neem extract, in producing the observed genotoxic effect is discussed.

Genotoxicity of a crude leaf extract of neem in male germ cells of mice.

The oral administration of a soxhlated crude ethanolic extract of leaves of neem (Azadirachta indica Ajuss; family Meliaceae) to adult male mice for 6 weeks (one spermatogenic duration) at the rate of 0.5, 1.0 or 2.0 g/kg body weight per day increased the incidences of structural changes and synaptic-disturbances in meiotic chromosomes and also caused more disruptions of meiosis. The extract reduced the sperm count and increased the frequency of spermatozoa with abnormal head morphology. It is suggested that at least one of the constituents of the extract may have interfered with the DNA. The result was chromosome strand breakages, or spindle disturbances, and the regulation of genes responsible for sperm shaping was affected.

Cytogenetic toxicity of leaf extract of Putranjiva roxburghii, a medicinal plant.

Young weaning Swiss albino mice were orally administered leaf extract of Putranjiva roxburghii at 0.5, 1.0 or 2.0 g/kg body weight/day for seven consecutive days. The results showed that the leaf extract significantly induced mitosis-disruptive chromosomal changes in bone marrow cells. No change in the incidence of structural abnormalities was, however, noticed among the metaphase chromosomes. It is proposed that the extract might have interfered with the spindle and other proteins causing polyploidy, aneuploidy, c-mitosis, etc.

Differential genotoxicity of the crude leaf extract of a medicinal plant, Casearia tomentosa.

The genotoxic potentiality of the crude leaf extract of Casearia tomentosa, a medicinal preparation, has been evaluated in Swiss albino mice. The extract significantly induced the division-disruptive chromosomal changes in bone marrow cells as well as in primary spermatocytes; the latter also exhibited marked increase in synaptic disruptions. A significant decrease in sperm count was noted. The incidence of structural damages in chromosomes, however, remained within the range of control level frequency. This herbal preparation, therefore, appears to be primarily spindle-poisoning in its action, but not clastogenic. The probable mechanism of this differential genotoxicity is discussed.

Prolonged murine genotoxic effects of crude extracted from neem.

Oral administration of a crude ethanol extract of the leaves of neem (Azadirachta indica A juss) to adult Swiss albino mice for 7 days at 5 mg, 10 mg or 20 mg/10 g bw/day significantly increased the incidence of structural and mitosis disruptive changes in metaphase chromosomes of bone marrow cells on days 8, 15 and 35th of observation. It is proposed that one or other of the many constituents of the extract, along with genera free radicals, interfered with DNA to yield chromosome strand breakage or produced spindle disturbances, inducing belated genotoxic effects.