Oxydative stress, anxiety and depression are associated with changes in cytokine levels. Natural products, including individual and combined plant extracts, have the potential to be used in the treatment of neuropsychiatric disorders. The goal of this study is to investigate the effects of two combined plant extracts, rich in flavonoids, on the levels of the cytokines TNF-α, IL-6, and IL-10 in rats subjected to models of acute cold stress and chronic unpredictable stress. The study utilized common medicinal plants such as Valeriana officinalis, Melissa officinalis, Crataegus monogyna, Hypericum perforatum, and Serratula coronata, which were combined in two unique combinations—Antistress I and Antistress II. The compositions of the used extracts were determined by HPLC methods. Pro- and anti-inflammatory cytokines in rats’ serum were measured with Enzyme-linked immunosorbent assay. The results from the acute stress model revealed that the individual extract of Crataegus monogyna decreased levels of TNF-α, while Serratula coronata, Hypericum perforatum, and Valeriana officinalis effectively reduced IL-6 levels. Both combinations, Antistress I and Antistress II, were effective in reducing TNF-α and IL-6 levels, with Antistress II also increasing IL-10 levels. In the chronic stress model, Hypericum perforatum extract decreased the levels of the pro-inflammatory cytokines TNF-α and IL-6, whereas extracts of Serratula coronata and Valeriana officinalis only reduced TNF-α levels. The two combined extracts, Antistress I and Antistress II, decreased TNF-α and IL-6 levels, while Antistress I also reduced the levels of the anti-inflammatory cytokine IL-10. The combinations of plant extracts used in our experiment have not been previously studied or documented in the available literature. However, based on our own experimental results, we can draw the conclusion that the combinations exhibit a more pronounced effect in reducing cytokine levels compared to the individual plant extracts.

Until now, the interest to plants from genus Scutellaria in Bulgaria has been focused mainly on the terpenes in them. The purpose of this study is to enrich the information on the composition of the Bulgarian Scutellaria species in terms of both polyphenolic content as well as primary metabolites such as mono-, oligosaccharides and organic acids. An aerial part of three Scutellaria species growing in four low mountain regions of Southern Bulgaria was used. The flavonoids scutellarin, baicalin, baicalein, wogonin, wogonoside, luteolin, chrysin and a caffeoyl phenylethanoid glycoside-verbascoside have been identified via HPLC in different extracts from Scutellaria altissima, Scutellaria albida and Scutellaria galericulata. The antioxidant activity of the extracts has been evaluated. The Scutellaria altissima from Mezek and Scutellaria galericulata from Parvenets we studied, which are the richest in flavonoids (represented mainly by baicalin, scutellarin and wogonoside), show the highest Oxygen Radical Absorption Capacity. Hydroxyl Radical Averting Capacity of Scutellaria albida from Mezek and Scutellaria altissima from Bachkovo is the most pronounced, probably due to the content of scutellarin and luteolin and chrysin, respectively. Antioxidant activity of aqueous, methanolic and 70% and 96% ethanol extracts were also determined by the electrochemical method.

The trend towards alternative medicine and naturopathy increases the interest in the use of natural products. This requires larger quantities of qualitative raw material of medicinal plants, including the well-known genus Echinacea. The purpose of this study was to evaluate the quality of E. purpurea and pallida cultivated in Kazanlak, Bulgaria. We developed and validated a rapid, reliable, and inexpensive HPLC method for the quantitative determination of chicoric, caftaric, and caffeic acids, and of cynarin, echinacoside, quercetin, and apigenin. The amount of chicoric and caftaric acids was monitored in different phases of plant development in aerial parts and roots. Maximal concentrations of chicoric acid (3.4%) were reported in roots in the seed-formation phase, and a concentration of 2.8% was reported in aerial parts in the vegetative phase. Caftaric acid was 0.9% in aerial parts in the vegetative and flowering phases and 0.5% in roots in the vegetative and seeding phases. Their amounts significantly exceed the requirements of the European Pharmacopoeia 8.0. Therefore, Kazanlak-grown E. purpurea could be a reliable raw material for the formulation of phytopreparations. In addition, the proposed method was applied to the detection and determination of the above-described substances in phytopreparations containing Echinacea from commercial sources. The amounts of the tested substances were found to vary widely.

Echinacea purpurea and Onopordum acanthium, which belong to the Asteraceae family, are widely used plants in traditional medicine. Their antioxidant, anti-inflammatory, antiviral, antibacterial, and antitumor effects are well known. However, there are no data on the effects of their combination. The aim of the present study was to combine E. purpurea with O. acanthium to study the in vivo immunomodulatory effect of two combinations and to compare it with that of single plants. Their total polyphenolic and flavonoid content and the amounts of individual compounds characteristic of both species were determined. The influence of the obtained extracts on the serum concentrations of cytokines IFN-γ, TNF-α, and IL-10 in experimental animals with lipopolysaccharide-induced systemic inflammatory response was investigated. This research found that a combination of E. purpurea/O. acanthium in the ratio 1:1 reduced the proinflammatory cytokines TNF-α (244.82 pg/mL) and IFN-γ (1327.92 pg/mL) compared to the LPS-control, respectively, (574.17 pg/mL) and (3354.00 pg/mL), and the combination E. purpurea/O. acanthium in the ratio of 3:1 significantly increased the levels of the anti-inflammatory cytokine IL-10 (1313.95 pg/mL) compared to the LPS-control (760.09 pg/mL). In conclusion, our results could be a basis for future biomedical research on creating phytopreparations with an immunomodulatory effect.

Nigella sativa (NS) is a promising medicinal plant with diverse therapeutic properties. This study aimed to investigate the impact of NS oil (NSO) on memory functions in rats with LPS (lipopolysaccharide)-induced neuroinflammation, as well as its effect on serum levels of inflammatory cytokines, neuropeptide Y (NPY) and brain-derived neurotrophic factor (BDNF). Male rats were divided into four groups: control, LPS-control, LPS+NSO 3 and 5 mL/kg. Neuroinflammation was induced by a single intraperitoneal LPS injection (2 mg/kg). The novel object recognition test (NORT) and Y-maze were used for the evaluation of memory processes. Recognition index (RI) and % spontaneous alteration (%SA) were registered, respectively. Blood samples for TNF-α, IL-1β, IL-10, BDNF, and NPY serum levels were taken. Thymoquinone, the active compound of the oil, was detected by high-performance liquid chromatography. NSO administration resulted in an improvement in spatial and episodic memory, as evidenced by increased % SA and RI compared to LPS-control. Treatment with NSO led to a significant reduction in pro-inflammatory cytokines and NPY, along with an increase in IL-10 and BDNF levels, when compared to LPS-control. In conclusion, NSO enhances BDNF production and regulates pro- and anti-inflammatory cytokines release, which probably contributes to the observed cognitive improvement in animals with experimental neuroinflammation.

Background: Echinacea purpurea (L.) Moench (EP) and Onopordum acanthium (L.) (OA) are promising medicinal plants with diverse biological activities but there is no information on the effects of their combinations. To harness the therapeutic potential of both while minimizing the risk of adverse effects, we prepared two combinations (CE1 and CE2) of EP and OA in ratios 1:1 and 3:1, respectively. Methods: Oxygen radical absorbance capacity (ORAC), hydroxyl radical absorbance capacity (HORAC), and an electrochemical assay were used to determine the antioxidant activity of the extracts in vitro. The anxiolytic and immunomodulatory properties were studied in rats. Animals were subjected to acute cold stress and anxiety-like behavior was evaluated by the elevated plus maze (EPM) and social interaction test (SIT). Serum IFN-γ, TNF-α and IL-10 levels were measured by ELISA. Results: CE2 demonstrated the highest antioxidant activity (1841.7 μmolTE/g by ORAC, 277.2 GAE/g by HORAC, and 39.6 by electrochemical method). Moreover CE2 produced anxiolytic-like effects—significantly increasing the open arms entries ratio (OAER; p < 0.001), open arms time ratio (OATR; p < 0.01) in the EPM, and prolonging the social interaction time (p < 0.05) versus the stressed control. OA increased OAER (p < 0.01) and OATR (p < 0.001), while EP increased only OAER (p < 0.01). CE1 showed no significant behavioral consequences. CE2 significantly reduced IFN-γ (p < 0.05), and IL-10 levels were elevated in OA and CE2 groups (p < 0.01). No significant changes in TNF-α levels were observed across groups. Conclusions: These findings indicate that CE2 and OA attenuate anxiety-like behavior and modulate the immune response primarily by stimulating IL-10 production.