Antimutagenic efficacy of some natural compounds on cyclophosphamide-induced p53 alterations.

Mutations in the p53 tumour suppressor gene have been associated with chemical carcinogens. Natural antimutagens are promising modulators for reducing the cancer risk. The present study was carried out to assess the protective efficacy of some natural antimutagens against p53 alterations. We investigated the ability of curcumin (100 mg/kg BW) and chlorophyllin (3 mg/kg BW) pretreatment, for three times per week for three successive weeks, to inhibit mutations induced by intraperitoneal injection of a single dose of 40 mg/kg BW of cyclophosphamide (CP). Forty male albino rats were assigned into four groups: control nontreated group, CP-treated group, curcumin-CP-treated group, and chlorophyllin-CP-treated group. Liver samples were collected for DNA isolation two days after CP injection. The isolated DNA was used in single-strand conformational polymorphism (SSCP) analysis of polymerase chain reaction (PCR)-amplified products of four regions: two in exon 5, one in exon 6, and one in exon 7. The amplified products of p53 different regions were found to be in the expected molecular size of the designed primers. SSCP analysis of these amplified products showed that CP-induced mutation in the p53 gene was found only in exon 7 shifting its electrophoretic mobility. Chlorophyllin treatment prior to CP injection had a more potent protective efficacy (80%) than that with curcumin (33.3%).

Protective effect of curcumin and chlorophyllin against DNA mutation induced by cyclophosphamide or benzo[a]pyrene.

The current study was carried out to evaluate the potency of curcumin and chlorophyllin as natural antioxidants to reduce the oxidative stress markers induced by cyclophosphamide (CP) and benzo[a]pyrene [B(a)P] which were used as free radical inducers. For this purpose, 126 male albino rats were used. The animals were assigned into 4 main groups: negative control group; oxidant-treated group (subdivided into two subgroups: cyclophosphamide-treated group and benzo[a]pyrene-treated group); curcumin-treated group; and chlorophyllin-treated group. Liver samples were collected after two days post the oxidant inoculation and at the end of the experimental period (10 weeks). These samples were examined for determination of liver microsomal malondialdehyde (MDA), DNA fragmentation, restriction fragment length polymorphism (RFLP) and 8-hydroxy deoxyguanosine (8-OHdG) concentration. Both CP and B(a)P caused increments in DNA fragmentation percentages, liver microsomal MDA, concentration of 8-OHdG and induced point mutation. Treatment of rats with either curcumin or chlorophyllin revealed lower DNA fragmentation percentages, liver microsomal MDA concentration, concentration of 8-OHdG and prevented induction of mutations, i.e., reversed the oxidative stress induced by CP and B(a)P and proved that they were capable of protecting rats against the oxidative damage evoked by these oxidants.