Structural diversity of salts of vitamin B6 with gentisic acid and the impact of a dihydrate form on antioxidant activity and boar sperm viability

Obtaining new pharmaceutical salts or cocrystals is a popular way to get compounds with better properties than their components. We report the synthesis of four different multi-component systems (I – IV) containing pyridoxine with gentisic acid (2,5-dihydroxybenzoic acid). Their crystal structures were studied by X-ray diffraction and FT-IR spectroscopy. Dihydrate form (IV), the easiest to obtain, was tested for antioxidant activity and preservation effects on boar sperm. Crystallization with gentisic acid significantly improved the free radicals scavenging ability of pyridoxine, increasing it more than three times. In vitro tests suggest that the supplementation of 2 or 4 mM solution of IV may support the quality of sperm cells, the observed effect is, however, breed-specific.