Physicochemical changes in bone bioapatite during the late postmortem interval pre- and post-burning

Postmortem chemical transformation of bone bioapatite can take place during early diagenesis resulting in a more thermodynamically stable mineral phase. This paper examines the impact of a 1-year postmortem interval on unburnt and burnt bone’s structural and chemical alterations. This question is of importance for the reconstruction of funerary practices involving cremation in the archaeological record, as well as forensic anthropological investigations. Fleshed pig (Sus scrofa) tibiae were left exposed in a field, then collected at 14, 34, 91, 180, 365-day intervals prior to being burnt in an outdoor fire (≤750 °C bone temperature). Fresh (fleshed) tibiae acted as unburnt and burnt controls. Also included in the study were two cremated human bone fragments from Middle/Late Neolithic (ca. 3300–2500 cal BC) Ireland. Samples were analysed for major and trace elements by wavelength dispersive electron microprobe analyser (EMP-WDS) and molecular structures by Fourier Transform Infrared Spectroscopy (FTIR). Linear regression, PCA, LDA, and MANOVA were performed for statistical analysis. Results indicate that the concentrations of elements associated with extracellular fluid (K, Na, Cl) change with the postmortem interval (PMI) and survive burning. K values under 0.07 ± 0.01 wt% in inner and mid-cortical zones of burnt bones suggest that bones were not burnt immediately after death. Using this criterion, results from the archaeological samples would indicate a PMI of at least weeks to months prior to cremation. Ca, P, Fe, Al, Si, and Sr are not significantly altered with burning, and Fe, Al, Si, Sr are also unaffected by the PMI. In unburnt bones increased crystallinity and carbonate loss are detectable in <1 year, but both are obscured by burning. Structurally, the carbonate to phosphate ratio (C/P), the phosphate high temperature (PHT), and cyanamide to phosphate (CN/P) are the most useful ratios for discriminating between unburnt and burnt bones

Assessing the reliability of microbial bioerosion features in burnt bones: a novel approach using feature-labelling in histotaphonomical analysis

Objectives Recent histotaphonomic studies have focused on the presence of features thought to be caused either by bacteria (microscopic focal destruction/MFD and cyanobacterial tunnelling) or fungal (Wedl tunnelling types 1 and 2) attack on unburnt bone. Identifying these characteristics on burnt bones could indicate the state of decomposition before burning, with important repercussions for both archaeological and forensic contexts. Materials and Methods Fleshed pig (Sus scrofa, N = 25) tibiae were left exposed on a field, then collected at 14-, 34-, 91-, 180-, 365-day intervals before being burnt in an outdoor fire (≤750 °C). Fresh (fleshed) legs (N = 10) acted as unburnt and burnt controls. Thin sections were examined using transmitted light microscopy and backscattered scanning electron microscopy. Diagenetic traits were quantitatively and systematically assessed by a novel data labelling application developed for this study. Results Features meeting the published characteristics of microbial bioerosion (‘Wedl tunnelling’, ‘lamellate’ and ‘budded MFD’) were significantly correlated with time since deposition on the unburnt bones. Only budded MFD increased significantly over time in the burnt groups. However, the presence features meeting the published characteristics of Wedl 2 tunnelling were present on the fresh burnt bones, indicating that they are an artefact. Discussion The presence of many features seemingly indistinguishable from those caused by bioerosion on the freshly burnt control bones suggests that burning is not only able to conceal features thought to be the result of bioerosion but can produce them as well. Thus, such features are not a reliable indication of bioerosion. Budded MFD may be a viable indicator but more research is required

Determining the postmortem timing of sharp force damage and the pre-burning condition of burnt bone

Major complications in the palaeopathological analysis of burnt human remains include distinguishing whether bone was fresh or dry at the time of burning, and whether trauma/damage was inflicted ‘perimortem’ or postmortem. Some prehistoric societies are suggested to have defleshed human remains prior to cremation, mostly classified based on the lack of warping and thumbnail fractures. The distinction between perimortem and postmortem sharp force trauma (SFT) characteristics has rarely been investigated on burnt bones. This study investigates whether these features are distinguishable on burnt bone, as well as assessing the rate of cutmark survival, and the presence of heat-induced fractures in relation to the bone’s pre-burnt collagen content. Pig (Sus scrofa domesticus) tibiae were left to decay in a field for 14, 34, 91, 180, and 365 days in Wytham Woods, Oxfordshire, UK. Prior to burning, bones were inflicted with SFT by a non-serrated and partially serrated knife and a flint blade (N = 15/bone). Fleshed bones with cutmarks and bones without trauma served as controls. Cutmark survival, features, and heat-induced fractures were recorded on the burnt bones and compared with the collagen extracted from unburnt bones at the abovementioned time intervals. Statistical analysis included linear regression and MANOVA. Heat-induced fractures did not depend on the limited collagen loss during the 1-year postmortem inverval (PMI) prior to burning. There was a loss (mean 18.4%) of identifiable cutmarks after burning. Significant alterations in the cutmark characteristics appeared after 6 months of exposure in burnt bones, marked by the increase in postmortem features, which can inform on the pre-burning PMI

Determining the postmortem timing of sharp force damage and the pre-burning condition of burnt bone

Major complications in the palaeopathological analysis of burnt human remains include distinguishing whether bone was fresh or dry at the time of burning, and whether trauma/damage was inflicted ‘perimortem’ or postmortem. Some prehistoric societies are suggested to have defleshed human remains prior to cremation, mostly classified based on the lack of warping and thumbnail fractures. The distinction between perimortem and postmortem sharp force trauma (SFT) characteristics has rarely been investigated on burnt bones. This study investigates whether these features are distinguishable on burnt bone, as well as assessing the rate of cutmark survival, and the presence of heat-induced fractures in relation to the bone’s pre-burnt collagen content. Pig (Sus scrofa domesticus) tibiae were left to decay in a field for 14, 34, 91, 180, and 365 days in Wytham Woods, Oxfordshire, UK. Prior to burning, bones were inflicted with SFT by a non-serrated and partially serrated knife and a flint blade (N = 15/bone). Fleshed bones with cutmarks and bones without trauma served as controls. Cutmark survival, features, and heat-induced fractures were recorded on the burnt bones and compared with the collagen extracted from unburnt bones at the abovementioned time intervals. Statistical analysis included linear regression and MANOVA. Heat-induced fractures did not depend on the limited collagen loss during the 1-year postmortem inverval (PMI) prior to burning. There was a loss (mean 18.4%) of identifiable cutmarks after burning. Significant alterations in the cutmark characteristics appeared after 6 months of exposure in burnt bones, marked by the increase in postmortem features, which can inform on the pre-burning PMI

First characterisation of flavonoid- and diarylheptanoid-type antioxidant phenolics in Corylus maxima by HPLC-DAD-ESI-MS

Corylus maxima Mill. (Betulaceae) leaves have been used in traditional medicine both internally and externally, nevertheless phytochemical exploration of the plant remains incomplete. In this study, the in vitro antioxidant activity and polyphenolic composition of the ethyl acetate and methanolic extracts of C. maxima leaves and bark are reported for the first time. The radical scavenging activities of the extracts were investigated by the ABTS and DPPH assays. All the extracts of C. maxima possessed notable antioxidant activity. By mean of a HPLC-DAD-ESI-TOF and a HPLC-DAD-ESI-MS/MS method, altogether twenty-two phenolics were tentatively characterised: one flavan derivative (. 1), seven flavonol derivatives (. 4, 6, 12, 13, 16, 20 and 21) and fourteen diarylheptanoids (. 2, 3, 5, 7-. 11, 14, 15, 17-. 19 and 22). The amount of the two main flavonoids - myricetin-3-. O-rhamnoside (. 6) and quercetin-3-. O-rhamnoside (. 13) - and two diarylheptanoids - oregonin (. 3) and hirsutenone (. 15) - in the extracts were determined by a validated HPLC-ESI-MS/MS method in multiple reaction monitoring (MRM) mode. Our results showed that C. maxima could be considered as a valuable source of pharmacologically important natural products that might contribute to the revaluation of the phytotherapeutical potential of the plant