Preliminary Phytochemical and Biological Evaluation of Rudbeckia hirta Flowers.

Black-eyed Susan (Rudbeckia hirta L.), a flowering plant with various traditional medicinal uses, has recently garnered interest for its therapeutic properties. However, little is known about the potential therapeutic activities of the plant species. The current study focused on conducting a comprehensive investigation into the chemical composition and bioactivity of black-eyed Susan cultivated in Romania. Untargeted metabolite profiling and UHPLC-HR-MS phytochemical analysis of the studied extract revealed the presence of more than 250 compounds pertaining to different classes, including sesquiterpene lactones, polyphenolic acids, flavonoids, amino acids, and fatty acids. The tested extract exhibited inhibitory activity against Gram-positive bacteria and showed promising antifungal activity. It also demonstrated potent antioxidant properties through iron chelation and 15-LOX inhibition capacities, as well as inhibition of cell growth, particularly on the MCF-7 cell line, suggesting potential anticancer effects. Therefore, current research provides valuable information on the antioxidant, antimicrobial, and antitumor potential of Rudbeckia hirta flowers. Implicitly, the discovery of such a wide range of biosubstances, together with the biological activity observed for the studied extract in these preliminary in vitro studies, paves the way for future investigation of the potential application of the plant in the pharmaceutical and nutraceutical sectors.

Spiro-Flavonoids in Nature: A Critical Review of Structural Diversity and Bioactivity.

Based on the literature data from 1973 to 2022, this work summarizes reports on spiro-flavonoids with a spiro-carbon at the center of their structure and how this affects their isolation methods, stereochemistry, and biological activity. The review collects 65 unique structures, including spiro-biflavonoids, spiro-triflavonoids, spiro-tetraflavonoids, spiro-flavostilbenoids, and scillascillin-type homoisoflavonoids. Scillascillin-type homoisoflavonoids comprise spiro[bicyclo[4.2.0]octane-7,3'-chromane]-1(6),2,4-trien-4'-one, while the other spiro-flavonoids contain either 2H,2'H-3,3'-spirobi[benzofuran]-2-one or 2'H,3H-2,3'-spirobi[benzofuran]-3-one in the core of their structures. Spiro-flavonoids have been described in more than 40 species of eight families, including Asparagaceae, Cistaceae, Cupressaceae, Fabaceae, Pentaphylacaceae, Pinaceae, Thymelaeaceae, and Vitaceae. The possible biosynthetic pathways for each group of spiro-flavonoids are summarized in detail. Anti-inflammatory and anticancer activities are the most important biological activities of spiro-flavonoids, both in vitro and in vivo. Our work identifies the most promising natural sources, the existing challenges in assigning the stereochemistry of these compounds, and future research perspectives.

Detailed metabolite profiling and in vitro studies of Urospermum picroides as a potential functional food.

Wild edible plants (WEP) are part of the Mediterranean culinary culture and can be used as famine foods in times of severe food shortages. Urospermum picroides is a WEP that grows under harsh conditions and represents an opportunity to expand and diversify the global food supply. However, little is known about its chemical profile. In this study, liquid chromatography coupled to HRESIMS allowed the identification of 77 metabolites in U. picroides extract, among which 12 sesquiterpene-amino acid conjugates are reported here for the first time. Due to the novelty of these conjugates, GNPS molecular networking was used to provide information on their fragmentation pathway. Further, the sesquiterpene enriched U. picroides extract showed a moderate anti-inflammatory effect in LPS-stimulated THP1-macrophages by increasing IL-10 secretion while decreasing pro-inflammatory IL-6 secretion at 50 µg/mL. Our study provides evidence for the potential use of U. picroides as an anti-inflammatory functional food and nutraceutical agent.