Welcome to my blog Sterigmatocystin: What You Need To Know.
Sterigmatocystin (STE) is a wide spread mycotoxin produced by Aspergillus fungi, with hepatotoxic and carcinogenetic proprieties.
Other species such as Bipolaris, Chaetomium, Emiricella are also able to produce STE. (source)
Mycotoxins (from the Greek words “mykes”: fungus and “toxicum”: poison) which mean fungus and poison are toxic secondary metabolites of low molecular weight produced by filamentous fungi (source)
Sterigmatocystin Food Sources
Sterigmatocystin is regularly detected in grains, corn, bread, cheese, spices, coffee beans, soybeans, pistachio nuts, animal feed (source).
A study carried out in European countries (Greece, Italy, The Netherlands, United Kingdom, Cyprus, Germany, Latvia, Lithuania and Poland) revealed the presence of STE in grains (soft and hard wheat, rye, corn, rice, barley, oat), in cereal products that have to be cooked beforehand (ground wheat, ground corn, ground barley, rice and pasta) and cereal products that they are consumed without treatment (breakfast cereals and cereal-based on infant food)
The main association in the research is with chronic liver diseases.
STE has also been associated with bloody diarrhoea in cattle that ate foods containing the fungus.
However when we take a closer look at the literature, and look at some of the in vitro studies available we can start to see that STE may cause mitochondrial dysfunction, oxidative stress and immune dysregulation. Mitochondrial dysfunction has been associated with an increasing list of conditions ranging from chronic fatigue to autoimmune conditions such as multiple sclerosis.
So, as it often the case with mycotoxins the list of symptoms that might manifest is very long. That’s not even considering that most of the time people are exposed to more than one type of mycotoxin/mould.
STE has been shown to be linked also to reduced immune response and disturbed balance of the adaptive immune system, as well as to the induction of oxidative stress, apoptosis, mitochondrial dysfunction and activation of specific pathways. (source)
STC shows different toxicological, mutagenic and carcinogenic effects in animals and has been recognised as a 2B carcinogen (possible human carcinogen) by the International Agency for Research on Cancer. (source)
Despite evidence of its carcinogenicity, only limited data regarding the detection of STE in human blood or urine are available in literature for a dose-response evaluation and further analysis is needed to state the real hazard STE represents for human health.
In this paper the authors show how STE causes mitochondrial dysfunction.
Sterigmatocystin Health Effects
Epidemiological evidence highlighted the existence of associations between STE exposure and the risk of cancer development. Epidemio- logical studies performed in China reveal that STE may be a putative etiological factor for gastric carcinoma, as suggested by the strong positive correlations existing between high levels of STE contamination in foodstuffs and a higher incidence of gastric cancer.
In particular, Hutanasu et al. (2011) detected STE in 26.2% of blood and urine samples collected from patients with liver cirrhosis and HCC. Similar results were obtained by Cao et al. (2018), who detected STE in the urine samples of 10 of the 30 (33%) patients with HCC, versus 3 of the 30 control patients (10%), whereas, for plasma samples, STE was detected in 12 of the 30 (40%) patients with HCC, versus 4 of the 30 control patients (13%), confirming the hypothesis of a possible role for this mycotoxin in the pathogenesis of the disease.
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Researchers have investigated the efficacy of Egyptian montmorillonite, a clay mineral, to adsorb STE. (source)
Oregano Oil – Other researchers have investigated the effect of oregano extract on the biosynthesis of STE. Significant reductions in STE biosynthesis during 21 days of incubation were observed for extract concentrations higher than 0.06 mL of extract/100 mL solution. These results showed that the oregano extract could be used as a food preservative to prevent food-borne fungal infections and STE production. (source)
Propolis – a natural resinous bee product collected by honeybee workers, has been used to investigate its effect on the growth of A. versicolor artificially grown on Ras cheese and STE production during a period of 90 days. Results revealed that treatment of fungus-inoculated cheese samples with 250 ppm propolis had a significant effect in decreasing the production of STE but no significant dif- ference in the growth of mould, whereas increased concentrations to 500 and 1000 ppm propolis had a significant inhibitory effect on the growth of mould, which was reduced to zero by treatment at the highest level.
Significant antifungal activity on the mycelial growth of A. versicolor and antimycotoxigenic activity on STE production were also demonstrated by onion and garlic essential oils individually, as well as in mixtures. Interestingly, the authors observed that the overall effect of the onion essential oil was more potent and lasted longer compared to the garlic essential oil. However, based on the findings, both of the essential oils may be considered a possible natural strategy to help to counteract A. versicolor growth and STE production.
Quercetin – In the present study, the cytoprotective effect of quercetin was tested. revealed that STE decreased cell viability, whereas pre-treatment of cells with QUE restored it. Quercetin was also found to counteract STE-induced ROS generation and decrease STE-induced up-regulation of the expression of the stress-inducible enzymes HO-1 and NOS-2. Pre-treatment with quercetin also prevented STE-induced nuclear translocation of NF-κB. results showed the down-regulation of TNF-α and IL-6 following STE exposure, suggesting a negative immunomodulatory effect of STE. In quercetin pre-treated samples, TNF-α and IL-6 were significantly further reduced, indicating the anti-inflammatory role of quercetin. (source).
Quercetin therefore exerts a cytoprotective role in STE-induced toxicity.
Liposomal Glutathione – STE induced an increase in ROS generation and LPO at all concentrations tested, as well as a depletion of glutathione levels, an increase in GSSG content and a decrease in GSH/GSSG ratio at the highest concentrations. findings suggest that STE could injure SH-SY5Y cells via oxidative stress and highlight the antioxidant role of the glutathione system.
You may like to read my blog Mould Illness: A UK Functional Medicine Approach for more information about treating mould illness and mycotoxins.
My Interview On Mycotoxins With Dr. Jill Crista