δ-Valerobetaine (δVB), a constitutive metabolite of ruminant milk, is produced in the rumen from free dietary Nε- trimethyllysine occurring ubiquitously in vegetable kingdom. The biological role of δVB is poorly known. Here, the antioxidant and anti-inflammatory potential of buffalo milk δVB was tested in vitro during high-glucose (HG)-induced endothelial damage. Results indicated that δVB (0.5 mM) ameliorated the HG cytotoxicity (0.57 ± 0.02 vs 0.41 ± 0.018 O.D. ( P < 0.01). Interestingly, buffalo milk extracts enriched with δVB showed improved significant efficacy in decreasing reactive oxygen species, lipid peroxidation, and cytokine release during HG treatment compared to milk extracts alone ( P < 0.05). It is noteworthy that δVB reduced the HG-activated inflammatory signal by modulating SIRT1 (0.96 ± 0.05 vs 0.85 ± 0.04 AU), SIRT6 (0.82 ± 0.04 vs 0.61 ± 0.03 AU), and NF-κB (0.85 ± 0.03 vs 1.23 ± 0.03 AU) ( P < 0.05). On the whole, our data show the first evidence of δVB efficacy in reducing endothelial oxidative stress and inflammation, suggesting a potential role of this betaine as a novel dietary compound with health-promoting properties.
Keywords: SIRT1; SIRT6; buffalo milk; hyperglycaemia; reactive oxygen species; δ-valerobetaine.