Hypericum foliosum Quality Botanical and Chemical Markers and In Vitro Antioxidant and Anticancer Activities.

Hypericum foliosum Aiton is an endemic Azorean Hypericum species. Even though the aerial parts of Hypericum foliosum are not described in any official pharmacopoeia, they are utilized in local traditional medicine due to their diuretic, hepatoprotective, and antihypertensive properties. This plant has previously been the subject of phytochemical characterization and has been studied for its antidepressant activity, showing significant results in animal models. The lack of a description of the main characteristics of the aerial parts, which would be necessary to properly identify this medicinal plant species, contributes to the possibility of misidentification events. We performed macroscopic and microscopic analyses that identified specific differential characteristics, such as the absence of dark glands, the dimensions of the secretory pockets in the leaf, and the presence of translucent glands in the powder. To continue our previous work on the biological activity of Hypericum foliosum, ethanol, dichloromethane/ethanol, and water extracts were prepared and studied for their antioxidant and cytotoxic activity. Extracts showed in vitro selective cytotoxic activity in human lung cancer cell line A549, colon cancer cell line HCT 8, and breast cancer cell line MDA-MB-231, with dichloromethane/ethanol showing higher activity against all cell lines (IC50 values of 71.49, 27.31, and 9.51 µg/mL, respectively). All extracts also showed significant antioxidant activity.

Hypericum Genus as a Natural Source for Biologically Active Compounds.

Hypericum L. genus plants are distributed worldwide, with numerous species identified throughout all continents, except Antarctica. These plant species are currently used in various systems of traditional medicine to treat mild depression, wounds and burns, diarrhea, pain, fevers, and their secondary metabolites previously shown, and the in vitro and/or in vivo cytotoxic, antimicrobial, anti-inflammatory, antioxidant, antihyperglycemic, and hepatoprotective activities, as well as the acetylcholinesterase and monoamine oxidase inhibitory activities. We conducted a systematic bibliographic search according to the Cochrane Collaboration guidelines to answer the question: "What is known about plants of Hypericum genus as a source of natural products with potential clinical biological activity?" We documented 414 different natural products with confirmed in vitro/in vivo biological activities, and 58 different Hypericum plant species as sources for these natural products. Phloroglucinols, acylphloroglucinols, xanthones, and benzophenones were the main chemical classes identified. The selective cytotoxicity against tumor cells, cell protection, anti-inflammatory, antimicrobial, antidepressant, anti-Alzheimer's, and adipogenesis-inhibition biological activities are described. Acylphloroglucinols were the most frequent compounds with anticancer and cell-protection mechanisms. To date, no work has been published with a full descriptive list directly relating secondary metabolites to their species of origin, plant parts used, extraction methodologies, mechanisms of action, and biological activities.