posted on 2022-03-14, 17:00authored byAlexander Incledion, Megan Boseley, Rachael L Moses, Ryan Moseley, Katja E. Hill, David W. Thomas, Rachel A. Adams
: Clays attributed to have medicinal properties have been used since prehistoric times and
are still used today as complementary medicines, which has given rise to unregulated “bioceutical”
clays to treat skin conditions. Recently, clays with antibacterial characteristics have been proposed
as alternatives to antibiotics, potentially overcoming modern day antibiotic resistance. Clays with
suggested antibacterial properties were examined to establish their effects on common woundinfecting bacteria. Geochemical, microscopical, and toxicological characterization of clay particulates,
their suspensions and filtered leachates was performed on THP-1 and HaCaT cell lines. Cytoskeletal
toxicity, cell proliferation/viability (MTT assays), and migration (scratch wounds) were further
evaluated. Clays were assayed for antibacterial efficacy using minimum inhibitory concentration
assays. All clays possessed a mineral content with antibacterial potential; however, clay leachates
contained insufficient ions to have any antibacterial effects. All clay leachates displayed toxicity
towards THP-1 monocytes, while clay suspensions showed less toxicity, suggesting immunogenicity.
Reduced clay cytotoxicity on HaCaTs was shown, as many leachates stimulated wound-healing
responses. The “Green” clay exhibited antibacterial effects and only in suspension, which was lost
upon neutralization. pH and its interaction with clay particle surface charge is more significant
than previously understood to emphasize dangers of unregulated marketing and unsubstantiated
bioceutical claims.
Incledion A, Boseley M, Moses RL, Moseley R, Hill KE, Thomas DW, Adams RA, Jones TP, BéruBé KA (2021).' A New Look at the Purported Health Benefits of Commercial and Natural Clays', Biomolecules.11(1):58. https://doi.org/10.3390/biom11010058