Exploring oxidative stress and epigenetic biomarkers in bees: insights into health effects of air pollution and diet – a pilot study

: Bees are vulnerable to environmental pollution, including toxic emissions from fire events, which can impact oxidative balance. This study was conducted as a pilot investigation with a relatively limited sample size and aimed to assess the levels of specific biomarkers [8-oxo-7,8-dihydroguanine (8-oxoGua), 8-oxo-7,8-dihydroguanosine (8-oxoGuo), 8-oxo-2'-deoxyguanosine (8-oxodGuo), 3-nitrotyrosine (3-NO₂Tyr), and 5-methylcytidine (5-MeCyt)] by HPLC‒MS/MS analysis in bees sampled before (May) and after (June) a landfill fire. The bees were divided into three groups: untreated (control), supplemented with Quassia amara, or fed probiotics. HPLC‒MS/MS analysis revealed no significant differences in the total bee population before and after fire. However, 8-oxoGua significantly increased in the control bees postfire (p < 0.05). Conversely, bees treated with Q. amara or probiotics tended to exhibit lower levels of oxidative and epigenetic biomarkers. However, only the Q. amara group showed a significant post-fire decrease in 8-oxoGua (p < 0.010). These observations should be considered preliminary and hypothesis-generating given the pilot nature and limited sample size of the study. Further investigations are required to elucidate their interaction mechanisms and long-term effects on pollinator health. Overall, this study highlights the potential of honeybees as early sentinels of oxidative stress, providing valuable insights for environmental monitoring and ecosystem health assessment.