Minocycline and St. John's wort as therapeutic drugs for human tauopathy

Biological Activity of Genus Hypericum Sect. Hypericum Species-H. tetrapterum, H. maculatum subsp. immaculatum, H. triquetrifolium

St. John's wort (Hypericum perforatum, Hypericaceae) has long been used in traditional medicine as a potent remedy, while many other species of this genus have not been thoroughly investigated. The study aimed to detect the biological activity, including antioxidant, antihyperglycemic, anticholinergic, antimicrobial and monoaminoxidase inhibitory potential, of water-alcoholic extracts of three species autochthonous for Serbia and Greece from plant genus Hypericum (section Hypericum-H. tetrapterum, H. maculatum ssp. immaculatum and H. triquetrifolium), followed by phytochemical profiling. The highest amount of phenolics was recorded in H. maculatum subsp. immaculatum extract, while the highest abundance of flavonoids was characteristic of H. tetrapterum extract. Hypericin and hyperforin, quercetin, and its flavonoid, rutin, were present in all of the evaluated species. The evaluated species were good scavengers of DPPH, OH and NO radicals, as well as potent reducers of ferric ions in FRAP assay. Furthermore, the evaluated species were shown as potent inhibitors of monoaminoxidase A and α-glucosidase and modest inhibitors of acetylcholinesterase, monoaminoxidase B and α-amylase. No anti-Candida activity was recorded, but the extracts were effective against MRSA Staphylococcus aureus and Enterococcus sp., as well as against Proteus mirabilis. The obtained results strongly highlight the need for further in vivo studies in order to better define the potential of the medicinal application of the studied species.

St. John's Wort Herbal Teas - Biological Potential and Chemometric Approach to Quality Control

St. John's wort has been used for centuries in traditional medicine of many cultures, and nowadays it is well-known as a clinically important antidepressant drug. Considering the rising market demand for Hyperici herba, quality control of crude drug is of paramount importance. In this paper we performed HPLC-DAD chemical profiling of St. John's wort tea samples obtained at local markets, pharmacies and health food stores in the Balkan Peninsula countries, Austria and Turkey. Furthermore, water alcoholic extracts of the collected samples were evaluated in terms of their antioxidant potential, as well as the ability to inhibit biologically important enzymes such as acetylcholinesterase, monoamine oxidases A and B (MAO-A and MAO-B), α-amylase and α-glucosidase. Significant variability within the samples in the quantities of hypericin, hyperforin, rutin, quercetin, gallic, chlorogenic, caffeic and p-hydroxybenzoic acid was noticed. Chemotaxonomic modelling enabled the identification of three clusters of samples based on the quantities of rutin, hypericin and hyperforin. Generally, the extracts exhibited a significant potential to inhibit MAO-A (median IC₅₀ = 10.01 μg/mL) and α-glucosidase (median IC₅₀ = 12.40 μg/mL). The results of antioxidant potential evaluation suggest strong neutralization of hydroxyl and nitroso radicals, but moderate inhibition of lipid peroxidation process. Overall, the conducted study emphasizes the possibility of St. John's wort teas quality control, taking into account unavoidable variability of chemical profile as well. The stated is of great importance when grinding degree of herbal material excludes taxonomic identification of biological origin as an option within quality control.