A preliminary study on the antibacterial activity and insect repellent properties of embalming fluids from the 18th Dynasty (1550–1292 BCE) in ancient Egypt

The ancient Egyptians believed in an afterlife where the body of a dead person would be needed by the spirit. In order to preserve the deceased in as lifelike condition as possible they developed artificial mummification to a high level of sophistication. It is widely believed that natron was the main desiccation agent in the preparation of Egyptian mummified bodies in the 18th Dynasty. Natron is a natural mixture of sodium chloride, sodium sulphate, sodium carbonate and sodium bicarbonate found in the Nile Delta which has significant desiccation properties, but it is currently unclear if natron has further beneficial properties for the mummification process. Previous work indicates that it does not deter insect colonisation in general, although it has been found to act as a killing agent of blow flies. In particular, we are aware of no studies investigating the antibacterial activity of natron nor the wider investigation of the insect repellent nature of ancient Egyptian mummification resins. This study investigated the properties of ancient Egyptian embalming fluids alongside their application in an artificial mummification of a human body at the Medico-legal Centre in Sheffield, UK. Antibacterial assays were used to compare the activity of a modern day antibiotic (Chloramphenicol) to those of key embalming ingredients used in ancient Egypt (natron, palm wine and pine resin). In addition, a field study using rabbit carcasses investigated whether pine resin has insect repellent properties. Results demonstrated that palm wine and natron had higher antibacterial activity than Chlorophemical against the Gram-positive bacteria, Staphylococcus aureus, and that natron had higher antibacterial activity than Chloramphenicol against the Gram-negative bacteria, Escherichia coli. The field study showed a delay in the colonisation of necrophagous insects and a temporal shift in the families of insects present on the carcasses treated with pine resin compared to control carcasses (no pine resin). We found no insect mortality on any of the carcasses during the study, indicating that the pine resin was acting as a repellent only and not as an insecticide. Although this is a preliminary study, the clear results strongly suggest that the embalming fluids used in mummification procedures during the 18th Dynasty had a number of properties which could affect the development of associated bacterial and insect communities.