Optical techniques help analyze ancient pills found in shipwreck

An international team of archaeologists, while investigating the ancient Relitto del Pozzino shipwreck off the coast of Tuscany in Italy, stumbled upon a tin container—hermetically sealed due to degradation—with well-preserved medicine tablets dating back to about 140–130 B.C.

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An international team of archaeologists, while investigating the ancient Relitto del Pozzino shipwreck off the coast of Tuscany in Italy, stumbled upon a tin container—hermetically sealed due to degradation—with well-preserved medicine tablets dating back to about 140–130 B.C. Seeking to delve more into how drugs have evolved into what they are today, the archaeologists analyzed fragments of the green-gray-colored, ~4-cm-diameter, 1-cm-thick tablets using a combination of optical techniques to decipher their composition.

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(a) A cylindrical tin container with a lid, known as a pyxis, was found by archaeologists among remnants of the ancient Relitto del Pozzino shipwreck that occurred 2,000 years ago off the coast of Tuscany in Italy, which contained (b) well-preserved medicine tablets. (Image courtesy of Gianna Giachi/Proceedings of the National Academy of Sciences)

Archaeologist and lead researcher Gianna Giachi, a chemist at the Archeological Heritage of Tuscany (Florence, Italy), and colleagues studied the tablet fragments using light microscopy, as well as scanning electron microscopy, for preliminary micromorphological analysis, during which they found fibers, starch grains (some measuring 20–25 μm in size), and pollen grains, mostly from olive oil. The fibers they found—which are perceived to be flax—were more numerous in the outer than in the inner parts of the sample. Then, the researchers took subsamples of the fragments and analyzed them using Fourier transform infrared spectroscopy (FTIR) and other non-optical spectroscopy techniques. Analysis revealed that the tablets contained zinc as the main element (75%), with silicon and iron as minor inorganic elements at 9% and 5%, respectively.1 Botanists on the research team discovered that the tablets also contained carrot, radish, parsley, celery, wild onion, and cabbage, says Alain Touwaide, scientific director of the Institute for the Preservation of Medical Traditions (Washington, DC) and member of the research team.

The researchers say that the composition and circular shape of the tablets suggest they may have been used to treat the eyes, perhaps as an eyewash, but could have been used to treat wounds as well. Their findings show the care that was taken in choosing complex mixtures of products in order to get the desired therapeutic effect and to help in the preparation and application of medicine, says Giachi.

"This information potentially represents essentially several centuries of clinical trials," Touwaide explains. "If natural medicine is used for centuries and centuries, it's not because it doesn't work."

REFERENCE

1. G. Giachi et al., Proc. Nat. Acad. Sci., doi:10.1073/pnas.1216776110 (January 7, 2013).

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