Cytogenotoxic evaluation of the acetonitrile extract, citrinin and dicitrinin-A from Penicillium citrinum.

Endophytic fungi are promising sources of bioactive substances; however, their secondary metabolites are toxic to plants, animals, and humans. This study aimed toevaluate the toxic, cytotoxic, mutagenic and oxidant/antioxidant activities of acetonitrile extract (AEPc), citrinin (CIT) and dicitrinin-A (DIC-A) of Penicillium citrinum. For this, the test substances at 0.5; 1.0; 1.5 and 2 µg/mLwere exposed for 24 and 48 h in Artemia salina, and 48 h in Allium cepa test systems. The oxidant/antioxidant test was evaluated in pre-, co- and post-treatment with the stressor hydrogen peroxide (H2O2) in Saccharomyces cerevisiae. The results suggest that the AEPc, CIT and DIC-A at 0.5; 1.0; 1.5 and 2 µg/mL showed toxicity in A. saline, with LC50 (24 h) of 2.03 µg/mL, 1.71 µg/mL and 2.29 µg/mL, and LC50 (48 h) of 0.51 µg/mL, 0.54 µg/mL and 0.54 µg/mL, respectively.In A. cepa, the test substances also exerted cytotoxic and mutagenic effects. The AEPc, CIT and DIC-A at lower concentrations modulated the damage induced by H2O2 in the proficient and mutant strains of S. cerevisiae for cytoplasmic and mitochondrial superoxide dismutase. Moreover, the AEPc at 2 µg/mL and CIT at the two highest concentrations did not affect the H2O2-induced DNA damage in the test strains. In conclusion, AEPc, CIT and DIC-A of P. citrinum may exert their toxic, cytotoxic and mutagenic effects in the test systems possibly through oxidative stress induction pathway.

Chloroacetonitrile (CAN) induces glutathione depletion and 8-hydroxylation of guanine bases in rat gastric mucosa.

Chloroacetonitrile (CAN) is detected in drinking-water supplies as a by-product of the chlorination process. Gastroesophageal tissues are potential target sites of acute and chronic toxicity by haloacetonitriles (HAN). To examine the mechanism of CAN toxicity, we studied its effect on glutathione (GSH) homeostasis and its impact on oxidative DNA damage in gastric mucosal cells of rats. Following a single oral dose (38 or 76 mg/Kg) of CAN, animals were sacrificed at various times (0-24 h), and mucosa from pyloric stomach were collected. The effects of CAN treatment on gastric GSH contents and the integrity of genomic gastric DNA were assessed. Oxidative damage to gastric DNA was evaluated by measuring the levels of 8-Hydroxydeoxyguanosine (8-OHdG) in hydrolyzed DNA by HPLC-EC. The results indicate that CAN induced a significant, dose- and time-dependent, decrease in GSH levels in pyloric stomach mucosa at 2 and 4 hours after treatment (56 and 39% of control, respectively). DNA damage was observed electrophoretically at 6 and 12 hours following CAN administration. CAN (38 mg/Kg) induced significant elevation in levels of 8-OHdG in gastric DNA. Maximum levels of 8-OHdG in gastric DNA were observed at 6 hours after CAN treatment [9.59+/-0.60 (8-OHdG/10(5)dG) 146% of control]. When a high dose of CAN (76 mg/Kg) was used, a peak level of 8-OHdG [11.59+/-1.30 (8-OHdG/10(5)dG) 177% of control] was observed at earlier times (2 h) following treatment. When CAN was incubated with gastric mucosal cells, a concentration-dependent cyanide liberation and significant decrease in cellular ATP levels were detected. These data indicate that a mechanism for CAN-induced toxicity may be partially mediated by depletion of glutathione, release of cyanide, interruption of the energy metabolism, and induction of oxidative stress that leads to oxidative damage to gastric DNA.

Developmental effects of trichloroacetonitrile administered in corn oil to pregnant Long-Evans rats.

Trichloroacetonitrile (TCAN) is a by-product of the chlorine disinfection of water containing natural organic material. When administered by gavage to pregnant Long-Evans rats in a medium-chain triglyceride vehicle, tricaprylin oil (Tricap), at a volume of 10 ml/kg, TCAN induced fetal cardiovascular anomalies at doses as low as 1 mg/kg/d (Smith et al., 1988). A slight but possibly biologically significant increase over the water control group in adverse pregnancy outcomes (resorptions, reduced fetal weight, and anomalies) was observed in the Tricap control group. This led us to reexamine the development effects of TCAN in a second vehicle, corn oil (CO). Five groups of approximately 20 pregnant female rats received TCAN in CO at 15, 35, 55, and 75 mg/kg/d, and in Tricap at 15 mg/kg/d (10 ml/kg dosing volume). Corn oil, Tricap, and water served as vehicle controls. Animals were treated by oral intubation on gestation d 6-18 (vaginal plug = d 0). Five out of 20 dams (75 mg/kg) died during treatment. Adjusted maternal weight gain was lower in females receiving 35 mg/kg TCAN or greater. The mean percent of nonlive implants per litter was elevated at 55 and 75 mg/kg TCAN (CO). The TCAN dose-response curve for fetal (but not maternal) effects was shifted to the right when CO was compared to Tricap. Fetal weight was reduced at 15 mg/kg TCAN (Tricap) and at > or = 55 mg/kg TCAN (CO). When TCAN was administered in CO, the mean frequency of soft-tissue malformations decreased with significantly fewer septal and great vessel cardiovascular defects observed. We hypothesize that the volatile haloacetonitrile, TCAN, may interact with the Tricap vehicle in such a way that effects on the developing cardiovascular system are potentiated. The lowest observed adverse effect level for TCAN (CO) was determined to be 35 kg/kg.

[Effect of d,l-alpha-methyl-3, 5, 3, 5-tetraiodothyronine ethylester hydrochloride (CG-635) on experimental hypercholesterolemia and atherosclerosis in rabbits (author's transl)].

To develop the prophylactics and the curatives for atherosclerosis, thyroxine derivative, CG-635, was assayed for its physiological activities in experimental atherosclerosis in rabbits fed with cholesterol. It was found that CG-635 possessed serum TC/TP value lowering activity (total cholesterol/total phospholipid) in normal and cholesterol fed rabbits for 3 weeks, and prevented the elevation of the value of cholesterol fed rabbits by daily injection for 7 weeks. CG-635 also depressed the hyperlipemia induced by cholesterol feeding, and its inhibitory effect was shown to be more marked on the increase of cholesterol than triglyceride, phospholipid and free fatty acid in serum. CG-635 did not, however, influence GOT, GPT and G-6-Pase activities in serum with increased cholesterol intake. From the histological findings it was proved that this compound prevented to a high degree the occurrence of atherosclerosis and fatty liver of cholesterol fed rabbits. Furthermore, it was recognized that thyroid hormone and the thyroid simulating hormone-like activities of CG-635 were much weaker than thyroxine, except for the action in the lipid metabolism.