Unravelling the Neuroprotective Effects of a Novel Formulation Based on Plant Extracts, Mg, and Vitamin B6

The aim of the present study was to investigate the phenolic composition and the efficacy of an innovative formulation based on Mg, Vitamin B6, and water extracts from Vitex agnus-castus, Crocus sativus, Melissa officinalis, Betula pendula, and Betula pubescens developed as an effective tool to face neuroinflammation and depression symptoms occurring in premenstrual syndrome (PMS). The formulation was analyzed through colorimetric and liquid chromatography methods for determining the content in phenols and flavonoids. Additionally, scavenging/reducing properties were investigated via 2,2-diphenyl-1-picrylhydrazyl (DPPH,) 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and horseradish peroxidase assays. The biocompatible limits were determined via allelopathy, the brine shrimp lethality test, and Daphnia magna cardiotoxicity assay. The formulation was then assayed in an experimental model constituted by isolated mouse cortex specimens exposed to K+ 60 mM Krebs–Ringer buffer, a toxic depolarizing stimulus able to reproduce the burden of inflammation/oxidative stress and the increased serotonin (5-hydroxytryptamine, 5-HT) impoverishment occurring in different neurological and psychiatric conditions, including depression. The results of the phytochemical analysis showed that the formulation is rich in benzoic acids, namely gentisic acid (155.31 µg/mL) and phenylethanoid compounds, namely hydroxytyrosol (39.79 µg/mL) that support the antioxidant effects measured via DPPH (IC50: 1.48 mg/mL), ABTS (IC50: 0.42 mg/mL), and horseradish peroxidase (IC50: 2.02 mg/mL) assays. The ecotoxicological models indicated the formulation as non-toxic, permitting the identification of a biocompatible concentration (1000 µg/mL) to be used in isolated mouse cortex exposed to K+ 60 mM Krebs–Ringer buffer. In this model, the gene expression of cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), estrogen receptor-1 (ESR1), prolactin receptor (PRLR), brain-derived neurotrophic factor (BDNF), and serotonin transporter (SERT) was determined by real-time PCR. In the isolated mouse cortex, the formula reduced COX-2, IL-6, SERT, ESR1, and PRLR gene expression and increased BDNF and IL-10 gene expression. Overall, the study corroborated the use of the formulation as an innovative tool to contrast inflammation, oxidative stress, and neurotransmitter impairment associated with PMS.