The potential effects of Zataria multiflora Boiss essential oil on growth, aflatoxin production and transcription of aflatoxin biosynthesis pathway genes of toxigenic Aspergillus parasiticus

This study aims at evaluating the effects of Zataria multiflora (Z. multiflora) essential oil (EO) on growth, aflatoxin production and transcription of aflatoxin biosynthesis pathway genes. Total RNAs of Aspergillus parasiticus (A.parasiticus) ATCC56775 grown in yeast extract sucrose (YES) broth medium treated with Z. multiflora EO were subjected to reverse transcription-polymerase chain reaction (RT-PCR). Specific primers of nor-1, ver-1, omt-A and aflR genes were used. In parallel mycelial dry weight of samples were measured and all the media were assayed by high-pressure liquid chromatography (HPLC) for aflatoxinB1 (AFB1), aflatoxinB2 (AFB2), aflatoxinG1 (AFG1), aflatoxinG2 (AFG2) and aflatoxin total (AFTotal) production. The results showed that mycelial dry weight and aflatoxin production reduce in the presence of Z. multiflora EO (100 ppm) on day 5 of growth. It was found that the expression of nor-1, ver-1, omt-A and aflR genes was correlated with the ability of fungus to produce aflatoxins on day 5 in YES medium. RT-PCR showed that in the presence of Z.multiflora EO (100 ppm) nor-1, ver-1 and omtA genes expression was reduced. It seems that toxin production inhibitory effects of Z. multiflora EO on day 5 may be at the transcription level and this herb may cause reduction in aflatoxin biosynthesis pathway genes activity.

Evaluation of protective efficacy of Spirulina platensis in Balb/C mice with candidiasis.

OBJECTIVE: This study was aimed at evaluating the immunostimulatory effect of Spirulina platensis in prophylaxis of Balb/C mice with systemic candidiasis. MATERIALS AND METHODS: In first experiment, 40 mice were divided into four groups, ten mice per each group, for cytokines assay. Animals received a dose of 800mg/kg of S. platensis for 4days and then were intravenously inoculated with 1×10(6) Candida albicans. Control groups received 0.2mL and 0.1mL normal saline for prophylaxis and inoculation, respectively. Five mice from each group were euthanized after 24hours and 72hours and the serum levels of IFN-γ and TNF-α were measured by Enzyme-linked immunosorbent assay (ELISA) method. In second experiment, two mice groups with systemic candidiasis, 11 mice per each group, were included to evaluate the survival rate. Animals were monitored for 30days and the kidneys, liver, lungs and spleen were analyzed for fungal invasion. RESULTS: The results indicated that the Spirulina-treated mice produced more IFN-g and TNF-α level than their control groups. This infected group showed that the mean survival time (28.86±2.7) was significantly (P<0.05) higher than control group (13.9±3.34). They also exhibited that fungal clearance in selected organs at death time represents significant differences between spleen and liver (P<0.05). CONCLUSION: Prophylaxis with S. platensis had synergistic effect through producing cytokines such as TNF-α and IFN-γ. Our results provide important information for the potential application of S. platensis in the treatment and resistance of Balb/C mice with systemic candidiasis.

Aflatoxin Detoxification in Rice using Citric Acid.

BACKGROUND: Aflatoxins cause health hazards to human and animals and has also economical problems. Therefore, the detoxification effect of citric acid was investigated in rice as the main food of Iranian people. METHODS: Initially 275 samples of rice were examined for aflatoxins by HPLC. The aflatoxins contaminated samples were later treated by aqueous citric acid and detoxification of aflatoxins were quantified using HPLC. RESULTS: Among the 275 samples analyzed, aflatoxin B(1) and aflatoxin B(2) were detected in 211(76.72% of total) samples. Aflatoxin B(1) was detected in 203(73.82% of total) samples with a mean and standard deviation of 2.3±10.21ppb. Aflatoxin B(2) together with aflatoxin B(1) were detected in only 8(2.91% of total) samples with a mean and standard deviation of 1.38±2.7ppb of aflatoxin B(2) and 2.99±1.56 of aflatoxin B(1) respectively. Aflatoxin B(1) level in 5 samples (1.82%) was above the maximum tolerated level of aflatoxin B(1) in Iran (5ppb). However considering the Iranian maximum tolerated level for aflatoxins in rice (30ppb), only 3(1.09%) samples were above the 30ppb and also in regard to the European maximum tolerated level for aflatoxins in rice (4ppb), only 9(3.27%) samples were considered as higher than 4ppb. CONCLUSION: The HPLC assay showed that although aflatoxins with a concentration of <30 and <4 ppb in the rice samples were completely degraded, but 97.22% degradation occurred in rice contaminated with ≥30 and ≥4ppb when treated with 1N citric acid. These results revealed the efficacy of 1N citric acid in reducing aflatoxins levels in rice.