Flavonoids are natural, plant-derived compounds which exert diverse biological activities, also valuable neuroprotective actions within the brain and currently are intensively studied as agents able to modulate neuronal function and to prevent age-related neurodegeneration. Among them, flavones isolated from Scutellaria baicalensis root exhibit strong neuroprotective effects on the brain and are not toxic in the broad range of tested doses. Their neuroprotective potential has been shown in both oxidative stress-induced and amyloid-beta and alpha-synuclein-induced neuronal death models. Baicalein, the main flavone present in Scutellaria baicalensis root, strongly inhibited aggregation of neuronal amyloidogenic proteins in vitro and induces dissolution of amyloid deposits. It exerts strong antioxidative and anti-inflammatory activities and also exhibits anti-convulsive, anxiolytic, and mild sedative actions. Importantly, baicalein, and also another flavone: oroxylin A, markedly enhanced cognitive and mnestic functions in animal models of aging brains and neurodegeneration. In the preliminary study, wogonin, another flavone from Scutellaria baicalensis root, has been shown to stimulate brain tissue regeneration, inducing differentiation of neuronal precursor cells. This concise review provides the main examples of neuroprotective activities of the flavones and reveals their potential in prevention and therapyof neurodegenerative diseases.

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Extracts of Scutellaria baicalensis display a wide spectrum of antiviral activity. It was of great interest to check the effect of baicalein and wogonin preparations on two important mechanisms of innate immunity: the secretion of cytokines and the natural resistance of human leukocytes to viral infection. To study the effect of S. baicalensis extracts on interferons (IFNs), tumor necrosis factor alpha (TNF-alpha), and interleukin (IL) production and virus replication, uninfected and vesicular stomatitis virus (VSV)-infected human peripheral blood leukocytes (PBLs) were used. Four pulverized preparations obtained from roots of Scutellaria and a Sigma-Aldrich preparation of purified baicalein were used in the study. RPMI extracts containing different amounts of baicalein and wogonin were used to study the effect on VSV replication in PBLs. PBLs express ex vivo individually differentiated cytokine-dependent resistance/innate immunity to viral infections. The degree of resistance was estimated on the basis of VSV replication in PBLs. The results obtained indicate that baicalein- and wogonin-containing extracts modulate cytokine production, that is inhibit IFN-alpha and IFN-gamma and stimulate TNF-alpha and IL (IL-12, IL-10) production. They also augment the resistance of PBLs to VSV. Extract from S. baicalensis containing baicalein and wogonin regulates the innate antiviral immunity by modulation of cytokine production and stimulation of human leukocyte resistance.

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