Lemnian Earth (LE) is an ancient therapeutic clay, that has been used for therapeutic purposes for the past 2,500 years and scientists have been puzzled by its supposed healing power. Often employed for different diseases, LE or terra sigillata or stamped earth has been recognized as a natural substance. However, recent studies write about its medicinal use possibly not coming from its organic components but a special process enhancing it by interacting a clay with fungus.
A recent study tested this hypothesis by experimenting with the co-culture of the common fungus Penicillium purpurogenum (Pp) and two types of clay slurries: It is therefore linked to smectite and kaolin which form the principal components of LE. Therefore, the outcomes illuminate potential mechanisms of action of LE for the modulation of gut microbiomes in supporting historical uses and indicating future helm with the current science-based approach.
This work examines the impact of a clay mineral SWy-2 smectite as well as the KGa-2 kaolin on Talaromyces purpurogenum cultures and the possible antimicrobial abilities of the cultures. The clays were selected based on their characterization and compatibility with the mineral content of the lignocellulose microenvironment. T. purpurogenum was then cultured together with these clays and the leachate was afterward tested for antibacterial activity against E. coli and S. aureus through the broth microdilution method for determination of Minimum inhibitory concentration (MIC).
Subsequent analysis featured identifying the fungal metabolites through ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS) and 30 bioactive secondary metabolites were detected. In-vivo, experiments included feeding the mice with the clay-treated leachates to determine their effects on the intestinal microbiota. For the fecal samples, 16S ribosomal ribonucleic acid (rRNA) gene sequencing and metabolomics were conducted on the fecal samples. The microbiome data analysis was done using quantitative insights into microbial ecology (QIIME) while statistical analysis involved R, with the incorporation of alpha and beta diversity indices.
Examination of specific taxa revealed changes in the microbial genera and metabolic pathways in response to the treatments. These systematic assessments incorporated the microbiome, metabolome, host microbiota, and advanced bioinformatics to elucidate biological changes resulting from T. purpurogenum and clay conjugation. The data obtained present information about the interactions between clay and fungi and their possible use in biomedical practice.
The research explored the reconfiguration of Lemnian Earth (LE) by simulating a clay-fungus interaction to analyze its biological effects, yielding four key findings:
Antibacterial Activity: When in contact with bacteria, the leachate of the co-culture of Penicillium purpurogenum (Pp) and smectite clay presented a promising antibacterial activity against both gram-positive and gram-negative bacteria. This implies that the interaction forms compounds that exhibit some biological activity that may be antibacterial.
Gut Microbial Diversity: In-vivo studies involving mice noted that supplements of Pp+smectite leachate aid the restoration of intestinal microbe diversification: a parameter that researchers use to study disease immunity and intestinal general health.
Specificity of Smectite: The Pp+kaolin interaction did not provide similar levels of antibacterial or microbiome-modulating effects, thus emphasizing the specificity of smectite clay for desired outcomes.
Metabolomic and Microbial Pathways: The Pp+smectite microbiome enhanced the SCFA, including butyrate which has anti-inflammatory and positive effects on gut barrier integrity and amino acids critical for biosynthesis regulation, which affects gut and systemic health.
The present research evaluated the bioactivity, the microbial community changes, and the metabolisms of leachates from Penicillium purpurogenum– smectite (SWY-2) or kaolin (KGa-2) co-culture. Among the leachates tested, the Pp+smectite showed the highest antibacterial activity particularly against Escherichia coli and Staphylococcus aureus compared to the Pp+kaolin and control treatments.
Consequently, by using LC-MS, the presence of ten bioactive fungal metabolites in Pp+smectite leachates was confirmed, with patulin, mitorubrinol, and roquefortine C having antibacterial and/or anti-inflammatory effects. The mice fed through Pp+smectite leachates mean that there is a shift in the composition of gut microbiota such that Firmicutes is enriched particularly Lachnospiraceae while Lactobacilli and Muribaculaceae are reduced.
It may also be more beneficial to the gut’s health because of the changes in the types of bacteria found in the intestines. Increased short-chain fatty acids (SCFA)-carnitine conjugates and the promoted expression of the genes associated with SCFA synthesis, amino acid metabolism, and gut immune regulation were identified. This process was complemented by downregulation of gene sequences involved in nucleotide biosynthesis that deserves further investigation.
This research also shows that co-culturing Pp with smectite shifts the levels of secondary metabolites and the gut microbiota, thereby increasing the levels of SCFAs. Such outcomes indicate that small molecules derived from clay-fungus co-cultures could enhance intestinal health and immune balance and therefore present novel therapeutic perspectives.
References: Milling S, Ijaz UZ, Venieri D, et al. Beneficial modulation of the gut microbiome by leachates of Penicillium purpurogenum in the presence of clays: A model for the preparation and efficacy of historical Lemnian Earth. PLoS One. 192024;(12):e0313090. doi:10.1371/journal.pone.0313090
