VARIVAX (Aesculus hippocastanum L.): A DIETARY SUPPLEMENT WITH ANTIOXIDANT AND ANTIDEPRESSANT POTENTIAL IN ADULT ZEBRAFISH

Varivax ( Natulab ®) is a dietary supplement composed of dry extract of horse chestnut ( Aesculus hippocastanum L.), standardized to 20% anhydrous escin and indicated for chronic venous insufficiency, pain, and leg swelling. In this context, the present study aimed to investigate the antioxidant and antidepressant effects of Varivax (VRX) and its possible neuromodulatory mechanisms. Initially, VRX was subjected to in vitro antioxidant activity assessment using the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] assays. For the in vivo assays, to evaluate non-clinical safety, adult zebrafish (ZFa; n=6/group) were treated (20μL; oral administration) with VRX (0.1, 1.0, or 10mg/mL), and sedative effects (open field test) and toxicity (96h) were assessed. To investigate the antidepressant effect, ZFa (n = 6/group) were subjected to the Tail Immobilization Test (TIT), and antidepressant-like activity was characterized by an increase in mobility time (s). Subsequently, the possible in vivo modulation of the serotonergic system by VRX was investigated, and in silico molecular docking was performed to evaluate the potential modulation of serotonergic receptors (5-HT 2A , 5-HT 1 , 5-HT 2A/2C , and 5-HT 3A/3B ) by escin. Fluoxetine was used as the reference drug for validating the results. As a result, VRX did not exhibit toxic or sedative effects in adult zebrafish and demonstrated antidepressant-like activity involving serotonergic receptors 5-HT 2A , 5-HT 1 , 5-HT 2A/2C , and 5-HT 3A/3B , which were supported by the interaction potential observed in the in silico assays. The results of in vivo and in silico analyses demonstrated that VRX exhibited an antidepressant effect at the highest dose tested, with a response comparable to fluoxetine. The present study highlights the medicinal potential of this supplement in the prospecting of phytopharmaceuticals for depression.