Tris[N-(prop-2-en-1-yl)hydrazinecarbothioamide]-Cobalt(III) Chloride as a Stimulator of the Total Antioxidant Status of Apis mellifera with Acaricidal Activity

This study investigates the synthesis and potential applications of the coordination compound cobalt(III) complex tris[<i>N</i>-(prop-2-en-1-yl)hydrazinecarbothioamide]-cobalt(III) chloride (<b>[Co(Tsc)₃]Cl₃</b>). The complex has been synthesized via the reaction of cobalt(II) chloride hexahydrate with <i>N</i>-(prop-2-en-1-yl)hydrazinecarbothioamide in ethanol. Its antioxidant activity has been evaluated using 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assay, demonstrating a significant effect with an IC₅₀ of 7.3 µmol/L. Toxicity evaluations using <i>Daphnia magna</i> showed a low half maximal inhibitory concentration (LC₅₀) of 56.3 µmol/L. Experimental results have showed that <b>[Co(Tsc)₃]Cl₃</b> significantly elevated the total antioxidant status (TAS) of the hemolymph of honeybees and larvae, increasing it by 5 and 8 times, respectively. The IC₅₀ values for antioxidant activity were 2.5 mg/mL in bee hemolymph and 1.3 mg/mL in larval hemolymph, notably lower than control values of 13.6 mg/mL and 10.0 mg/mL. The stimulatory effect of the coordination compound <b>[Co(Tsc)₃]Cl₃</b> on TAS was five times higher than that of vitamin C. Additionally, <b>[Co(Tsc)₃]Cl₃</b> exhibited acaricidal properties, effectively inhibiting <i>Varroa destructor</i> with an lethal concentration (LC₅₀) of 0.2 µmol/L. These findings indicate that this cobalt complex could serve both a natural antioxidant and an effective acaricide, offering a promising approach to improv bee health and sustainability in apiculture.