A key direction in the search for and designing of new prophylactic tools edible herbs rich in biologically active compounds [1]. For example, a group of preparations based on metal derivatives of chlorophyll has been extensively studied in the past years. These preparations, on the one hand, can compensate for the deficiency of one or another microelement in the body; on the other hand, they exhibit various biological activities [1][2][3]. To this end, or great interest is tsinkovit, a zinccontaining derivative of chlorophyll, which allows compensate for zinc deficiency in the body, which may cause may prepathological and pathological conditions [1,4].However, to make a decision to introduce tsinkovit in practice, with regard for its complex chemical composition, a comprehensive experimental study of the mechanism of its action and possible toxic properties should be performed. It should be emphasized that studies of the effect of this preparation on the enzymes involved in metabolism of neurotransmittersmonoamine oxidase (MAO) and acetylcholinesterase (ACE)-have not been performed earlier. It is known that MAO and ACE are the key enzymes in metabolism of endogenous amines, where they implement mediator and regulatory functions, and in the system of cholinergic nerve impulse transmission in the brain and muscles [5,6]. The constancy of ACE activity is essential for the maintenance of normal functioning of the body [5]. It was shown that some effectors, such as organophosphorous and carbamate compounds, sharply decrease ACE activity in different sections of the brain [5]. An increase in ACE activity is observed in poisoning with cocaine [7] and heavy metals [8] and in emotional stress [9]. The data on MAO activity derangement in different pathologies are very important for modern medicine [6].In view of this, we studied the effect of doses of tsinkovit on MAO and ACE activity in three brain sections-the striatum, hypothalamus, and medulla-and MAO activity in the liver and kidneys.The effect of different doses of tsinkovit was studied with male Wister rats weighing 180-200 g. Animals were divided into five groups: four experimental and one control (24 animals in each group). Animals of all groups were kept under equal conditions and received the same balanced diet. Rats of experimental groups received tsinkovit daily with food up to one month at doses of 0.75, 7.5, 100, and 500 mg/kg. Animals of the experimental and control groups (eight animals in each group) were decapitated 10, 20, and 30 days after the beginning of the experiment. Immediately after decapitation, the liver and kidneys were extracted. After opening the skull, and three sections of the brain (the striatum, hypothalamus, and medulla) were extracted as well. Extracted tissues were immediately frozen and stored in a refrigerator at -4°C for 1-2 days. To study the activity of ACE, brain tissues were homogenized in a glass homogenizer in nice volumes (w/v) of 0.05 M sodium-potassium phosphate buffer (pH 7.4) (1 : 9 w/v). Before measuring ACE activity,...