An adhesive used by Neanderthals 200,000 years ago has been found to have antibacterial properties, raising the possibility that it was also used to treat wounds.
A research team has confirmed that
Antibacterial properties of experimentally produced birch tar and its medicinal affordances in the Pleistocene | PLOS One
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0343618
CBU Research Team Helps Uncover 200,000-Year-Old Neanderthal Healthcare Secretary - Cape Breton University
https://www.cbu.ca/newsroom/releases/cbu-research-team-helps-uncover-200000-year-old-neanderthal-healthcare-secret/
While Neanderthals are often perceived as 'people who hunted using stone tools,' recent studies have revealed evidence of their use of plants and even traces suggesting they cared for the injured and sick. This research explores the possibility that birch tar, which Neanderthals used as an adhesive, may have had other uses.
The birch tar that the research team focused on is a substance made from the bark of birch trees, such as white birch. It has been found in Middle Paleolithic sites in Europe, and until now it was thought to have been mainly used as an adhesive to fix stone tool blades to wooden handles.
The researchers who conducted this study included Tcharck Siemsen from the University of Cologne and the University of Oxford, Adelonke Oldare and Matthias Bielenstil from Cape Breton University, and Marcel Schemmel from the University of Liège.
The research team used the bark of two types of hippopotamus trees, which were widely found in Europe during the time of Neanderthals, to create birch tar using three different methods.
Image a below shows an actual fragment of birch tar found at the Middle Paleolithic site of Königsaue in Germany, while images b through f illustrate birch tar production methods assumed to be from the time when Neanderthals lived. b represents the 'condensation method using grooves lined with stones,' c represents the 'bark roll method' where rolled bark is heated underground, d represents the 'condensation method' where the components released by heating are condensed and collected on the surface of stones, e represents the 'bit roll method' where bark rolls are heated in a hole and the tar is collected below, and f represents the 'method using a mound-like structure' where fire is used above to heat and the tar is collected below. In this study, the 'condensation method' (d) and the 'method using a mound-like structure' (f) were mainly used, and a modern method using cans was also used for comparison.
The research team tested each type of birch tar to determine 'how well it could inhibit bacterial growth.' The results showed that birch tar exhibited moderate antibacterial activity against Staphylococcus aureus, a type of bacteria that can cause wound infections. The size of the area where bacteria did not grow varied among samples, ranging from no effect to 10.5 ± 0.7 mm, with an average of 7.5 ± 0.17 mm.
The research team stated that while there was some variation in the results depending on how birch tar was made, antibacterial properties were confirmed in all methods, and that the effectiveness is not determined solely by the method of preparation.
Furthermore, Birchtal was not effective against all bacteria; while it showed antibacterial activity against Staphylococcus aureus, it did not show antibacterial activity against E. coli. Therefore, the research team believes it is difficult to consider Birchtal as a broadly and strongly effective agent against many bacteria like modern antibiotics, and that its effectiveness was limited to certain types of bacteria.
Staphylococcus aureus is a bacterium that can cause infections accompanied by redness, swelling, pain, and pus if it enters through a wound. From this perspective, the research team suggests that birch tar may have been used not only as an adhesive, but also as a material to cover wounds or applied to the skin.
However, this study only revealed that the birch tar created by the research team had antibacterial properties; it did not find direct evidence that Neanderthals actually used birch tar because they knew it was effective for treating injuries or skin problems. This finding suggests that a substance previously thought to be primarily an adhesive may have had other uses.
Related Posts:
in Science, Posted by log1b_ok