Study On The Safety Evaluation And Control Methods Of Four Species Of Boletus

Due to the delicious taste, Boletus, a very important genus of microfungi, are popular in many countries, though these mushrooms include both edible and poisonous species. Because of the lack of effective methods to detect and control their toxicity, it is necessary to evaluate the safety of Boletus.In this article four species of Boletus: Boletus tomentipesl, Boletus speciosus Frost, Boletus Calopus Fr and Boletus edulis Bull. Fr were investigated based on their components, toxicity evaluations and chromatogram fingerprints after different process and cooking methods by HPLC. The conclusions were reported as following:1. The content ranges of protein, fat, coarse fiber of these boletus were 4.38-5.42 g/100g, 2.47-3.07 g/100g, 1.23-1.56 g/100g, respectively. The content ranges of ion, calcium, zinc were 1.96 -3.80 mg/100g, 14.6 -29.8 mg/100g, 0.65 -0.97 mg/100g, respectively. The four species of boletus are nutrient food resources with high content protein and low fat.2. Arsenic was not detected in all the four samples. The content ranges of lead, cadmium, total mercury were 0.45-0.62mg/kg, 0.075-0.105mg/kg, 0.06-0.73mg/kg, respectively. Lead and cadmium of the four samples were within the limitation of state hygienic standard. But the content of total mercury in Boletus speciosus and Boletus Calopus were 0.45mg/kg and 0.73mg/kg, respectively, which were 3.5 and 6.3 times higher than state standard limitation. So the eating amount in a single time or a short period should be controlled.3. Acute oral toxicity tests revealed that all the Boletus samples were actually non-toxic, for MTD of Boletus tomentipesl, Boletus speciosus, Boletus Calopus and Boletus edulis exceeded 20g/Kg.bw, 13.3g/Kg.bw, 20g/Kg.bw and 13.3g/Kg.bw, respectively. Boletus tomentipesl causing mice slight paralysis showed that it contained neurotoxin. But the boiled & baked Boletus tomentipesl is not neurotoxic in the acute oral toxicity test.4. The genotoxicity of Boletus is evaluated by Ames test and micronucleus test in vicia faba root tip cells.In genotoxicity test, the relative mutation rate of TA98 strain induced by extract from Boletus edulis was 81.8%-88.0 %. And the relative revertants of TA97 and TA102 stains increased while the extracts dosage increasing. The certain reverse effect on TA98 strain revealed that Boletus edulis could cause frameshift mutation. The micronucleus rate range in vicia faba root tip cell was 27-33%e, 57% higher than negative, and the extracts has no antimutagenicity in micronucleus induced by cyclophosphamide.The extract from Boletus speciosus significantly inhibited the reverse mutation of Ames stains. When the dosage exceeded 16.7mg, no colony was formed. In micronucleus test, the MCN rate of root tip cell is 20-26‰. The inhibitory rate in micronucleus induced by cyclophosphamide was 55.5%. The extract from Boletus speciosus showed antimutagenic activity.The relative revertants rate of TA97, TA98, TA100, TA102 strains induced by extract from Boletus Calopus were 47.5%, 24.2%, 35.6%, 26.9%, respectively, all not exceeding two fold of their corresponding spontaneous reverting colonies, and showing no dose-effect relations. In micronucleus test, the MCN rate is 24-30‰, the mutagenicity on vicia faba root tip cell was not significant. The inhibitory rate of micronucleus induced by cyclophosphamide was 61.1%.The relative revertants of Ames strains induced by extract from Boletus tomentipesl decreased while dosage increasing. The inhibitory rate of relative revertants of TA97, TA98, TA100, TA102 were 100%, 100%, 74.1%, 100%, respectively. In micronucleus test, the MCN rate was 22 -32‰, showing no mutation effect on vicia faba root tip cells. The inhibitory rate of micronucleus induced by cyclophosphamide was 64.8%, showing strong antimutagenic effect.5. Comparing the HPLC fingerprints of boiled and baked Boletus tomentipesl to fingerprints after processed by baking, vapor heating, microwave heating, the similarity of chromatograms revealed that boiled, vapor heated, microwave heated Boletus tomentipesl have no neurotoxicity, for the boiled and baked Boletus tomentipesl was demonstrated non-neurotoxic in acute oral toxicity test.