Mineral compounds, as pigments and therapeutics, appeared regularly in the technical and medical texts of the Greco-Roman (G-R) world. We have referred to them as G-R medicinal minerals and we suggest that despite their seeming familiarity, there are actually many unknowns regarding their precise nature and/or purported pharmacological attributes. Earth pigments are part of that group.
This paper presents a brief overview of our work over the past twenty years relating to: a. the attempt to locate a select number of them in the places of their origin; b. their chemical/ mineralogical characterisation; c. the study of their ecology via the identification of the microorganisms surrounding them; d. their testing as antibacterials against known pathogens. In the process, and to fulfil the above, we have developed a novel methodological approach which includes a range of analytical techniques used across disciplines (mineralogy, geochemistry, DNA extraction and microbiology).
This paper focuses on a select number of earth pigments deriving from the island of Melos in the SW Aegean, celebrated for its Melian Earth, a white pigment, and asks whether they might display antibacterial activity. We demonstrate that some (but not all) yellow, green and black earth pigments do. We also show that how they were dispensed (as powders or leachates) was equally important. The results, although preliminary, are informative.
Given their use since deep time, earth pigments have never lost their relevance. We suggest that the study of their ecology and potential bioactivity allows for a better understanding of them.
- earth pigment
- manganese oxide
- antibacterial activity