Comparison of sterilisation methods for deer velvet antler extracts and their impact on anticancer activity

Natural extracts tested for potential effects in human health are susceptible to contamination, particularly when samples are often obtained from outdoor environments. Deer velvet antler (DVA) extracts have broad anticancer effects. As sterile samples are required for effective experimentation in cell cultures, we evaluated the most common sterilisation methods to get rid of microbial contamination. We also investigated whether the sterilisation method affected the anti-cancer activity of the DVA extract on human tumour cells. Two antler sections (tip and base) were subjected to water-based extraction. This study compares lyophilised and non-lyophilised DVA extracts. Subsequently, DMEM and LB culture media containing DVA extract were assessed for contamination. The amount of protein was quantified by BCA and visualised by polyacrylamide gel electrophoresis. To analyse the anticancer effect, a cell viability assay was performed on colorectal cancer cell lines. Finally, tumour biomarkers were evaluated by flow cytometry in colorectal cancer cells. Filtration was the sterilisation method that removed the highest microbial load. It reduced cell viability at a concentration of 1 mg/mL of total protein by up to 37% ± 10% (DVA-T) and by up to 69% ± 8% (DVA-B). Furthermore, the protein expression levels of SW480 colorectal cancer cells exhibited a significant increase in response to lyophilised DVA extracts in comparison to non-lyophilised extracts. The data obtained from this study indicate that the selected sterilization approaches allow preservation of protein integrity and in vitro bioactivity of DVA extracts, supporting their standardized preparation for further biological evaluation.