Identification and Cytotoxic Activities of Two New Trichothecenes and a New Cuparane-Type Sesquiterpenoid from the Cultures of the Mushroom Engleromyces goetzii

Engleromyces goetzii is a traditional medicinal mushroom that is widely used to treat infection,inflammation and cancer in Tibet,Sichuan and Yunnan provinces of China.Two new trichothecenes,engleromycones A and B(1 and 2),one new cuparane-type sesquiterpenoid named infuscol F(11),eight known trichothecene analogs,sambucinol(3),3-deoxysambucinol(4),trichothecolone(5),trichodermol(6),8-deoxytrichothecin(7),trichothecin(8),trichothecinol B(9)and trichothecinol A(10),and one known cyclopentanoid sesquiterpene cyclonerodiol(12)were isolated from the cultures of E.goetzii.The new compounds were elucidated through spectroscopic analyses.The anticancer effects of trichothecenes 1–10 were examined in the HL-60,SMMC-7721,A549,MCF-7,and SW-480 human cancer cell lines using an MTT assay.Trichothecinol A(10)significantly inhibited the growth of MCF-7 cells,with an IC50 value of 0.006 lM,which was comparable to the cytotoxic activity of the positive control,paclitaxel,indicating that trichothecinol A(10)represents a potential anticancer agent.

Macrocyclic trichothecenes from Myrothecium verrucaria PA 57 and their cytotoxic activity

Four novel macrocyclic trichothecenes,termed mytoxins D-G(1-4),along with four known analogs(5-8),were isolated from the ethyl acetate extract of fermented rice inoculated with the fungus Myrothecium verrucaria PA57.Each compound features a tricyclic 12,13-epoxytrichothec-9-ene(EPT)core.Notably,mytoxin G(4)represents the first instance of a macrocyclic trichothecene incorporating a glucosyl unit within the trichothecene structure.The structures of the newly identified compounds were elucidated through comprehensive spectroscopic analysis combined with quantum chemical calculations.All isolated compounds demonstrated cytotoxic activity against the CAL27 and HCT116 cell lines,which are models for human oral squamous cell carcinoma and colorectal cancer,respectively.Specifically,mytoxin D(1)and mytoxin F(3)exhibited pronounced cytotoxic effects against both cancer cell lines,with IC_(50)values ranging from 3 to 6 nmol·L^(-1).Moreover,compounds 1 and 3 were found to induce apoptosis in HCT116 cells by activating caspase-3.

Occurrence of <i>Fusarium</i>species and associated T2-toxin in Kenyan wheat

Survey covering 120 wheat fields was conducted in three wheat-growing districts of Kenya during the 2008 cropping season to determine the incidence of Fusarium head blight (FHB) and T2-toxin contamination in grain. FHB incidence was determined as the number of blighted ears per 10m2. Information gathered included wheat production practices, rainfall and temperature data. Fungal pathogens were isolated from wheat stems, heads, straw, grains and soil and identified based on cultural and morphological characteristics. Wheat grain samples were analyzed for T2-toxin by competitive Enzyme Linked Immunosorbent Assay (ELISA). High FHB incidences of up to 88% were recorded. Fungal genera isolated included Fusarium, Epicoccum, Trichoderma, Alternaria and Penicilium. Wheat plant parts with high infection with Alternaria and Epicoccum had corresponding low levels of Fusarium spp. Whereas Fusarium spp. were the most common fungal pathogens in stems, heads and soil, Epicoccum was frequently isolated from straw and grains. Fusarium speciesisolated included F. poae, F. graminearum, F. stilboides, F. verticilloides, F. fusarioides, F. tricinctum and F. heterosporum with F. poae and F. graminearum accounting for approximately 40% of all Fusarium infections. T-2 toxin was detected in all the grain samples and varied from 3 to 22 ppb. The study showed that FHB and T2-toxin are prevalent in the study districts and the high diversity of Fusarium species implies a challenge in FHB management as well as a risk of chronic T2-toxin exposure to humans and livestock.

Effects of <i>Myrothecium verrucaria</i>on Ultrastructural Integrity of Kudzu (<i>Pueraria montana var. lobata</i>) and Phytotoxin Implications

The fungus Myrothecium verrucaria (Alb. & Schwein.) (MV), originally isolated from diseased sicklepod (Senna obtusifolia L.), has bioherbicial activity against kudzu and several other weeds when applied with low concentrations of the surfactant Silwet L-77. To more fully understand the initial events of MV infection or disease progression, and to improve knowledge related to its mechanism of action, the effects of MV and its product (roridin A) on kudzu seedlings were examined at the ultrastructural level. Ultrastructural analysis of MV effects on kudzu seedlings revealed a rapid (~1 h after treatment) detachment of the protoplast from the cell wall and plasmodesmata appeared to be broken off and retained in the wall. These symptoms occurred well in advance of the appearance of any fungal growth structures. Some fungal growth was observed after severe tissue degeneration (24 to 48 h after treatment), but this occurred primarily at the extra-cellular location with respect to the kudzu tissues. Kudzu seedlings treated with roridin A, a trichothecene produced by the fungus, exhibited some symptoms similar to those induced by the fungus applied in spore formulations with surfactant. The overall results are the first to report the ultrastructural effects of this bioherbicide on plants and suggest that penetration of a phytotoxic substance(s) in the fungal formulation was facilitated by the surfactant, and that roridin A exerts phytotoxicity toward kudzu.

The Nature, Sources, Detections and Regulations of Mycotoxins That Contaminate Foods and Feeds Causing Health Hazards for Both Human and Animals

Mycotoxins are toxic secondary metabolites produced by fungus kingdom. Fungi (molds) under aerobic and optimum conditions of humidity and temperature consume nutrients for proliferation and mycotoxin production (secretion). There are seven major groups of mycotoxins produced by different species of toxigenic fungal genus. Mycotoxins production from these toxigenic fungi depends on the surrounding intrinsic and extrinsic environments. These seven mycotoxins groups that contaminate grains, foods and animal feeds are: Aflatoxins, Trichothecene, Ochratoxins, Ergot alkaloid (Ergolin), Fumonisins, Patulin, and Zearalenone. These mycotoxins are capable of causing health hazards and death for both human and animals by effecting mammalian cells, causing a number of problems in normal cell function and a wide variety of clinical symptoms of diseases. These mycotoxins are varied in their toxicity depending on the infected host (human or animal) and the host susceptibility (immunity). The major concern of food and feed industries is the contamination of food products and animal feed supplies by these mycotoxins. Worldwide Health Organization (WHO), and Food and Agriculture Organization (FAO) are responsible to regulate the acceptable (tolerable) levels of these mycotoxins in grains, food and feed supplies to ensure the safety and health for both human and animals. Understanding fungal ecology and factors that affect fungal proliferation and mycotoxins production by these toxigenic fungi in agriculture crops as raw materials for both human food and animal feed products, plus understanding the chemistry and property of these mycotoxins, methods of detection, illness symptoms, and comply with regulatory guidance established by World Health Organization (WHO)/Food and Agriculture Organization (FAO) are key factors to prevent or minimize foods/feeds contamination and the toxicity of these mycotoxins for both human and animals health, plus reducing economical loss.