The genus Hypericum (Hypericaceae) contains a variety of structurally diverse natural products which possess a wide array of biological properties. The present study examined quantitative variations in total hypericin, phenols, and flavonoids in Hypericum triquetrifolium Turra. in relation to phenological development. Plant material was harvested at different phenological stages (vegetative, full flowering, and mature fruiting stages). The amounts of bioactive compounds in whole shoots were assayed. The highest total hypericin, phenolic, and flavonoid contents were observed at the full flowering stage.
Apart from a large amount (ca. 2.0%) of α-bisabolol β-D-fucopyranoside (2a), the aerial parts of the Mediterranean weed Carthamus glaucus afforded an unusual triglyceride (E-2-crotonyl-1,3-distearolylglycerol, 7), two lipophilic flavonoids (6a,b), and a series of bisabolane fucopyranosides variously acylated on the sugar moiety (2b-e) or oxidized on the terpenoid core (3, 4a,b, 5a,b). The fucopyranoside 2a is more soluble in polar media and more versatile in terms of formulation than its aglycone [(-)-α-bisabolol, 1], an anti-inflammatory cosmetic ingredient in current short supply in its natural form. A comparative investigation of the activity of α-bisabolol (1a), the fucopyranoside 2a, and its senecioate 2b on transcription factors involved in inflammation and cancer pathways (NF-κB and STAT-3) showed only marginal activity on NF-κB inhibition for all compounds, while STAT-3 was inhibited potently by the fucoside 2a and, to a lesser extent, also by α-bisabolol. These observations qualify 2a as an easily available compound, both as an apoptotic lead structure and as a potential alternative to natural α-bisabolol (1) for pharmaceutical and/or cosmetic development.
The essential oils of Hypericum scabrum, Hypericum scabroides and Hypericum triquetrifolium were studied for the first time for their antimicrobial activity against nine organisms. All the essential oils exhibited some broad spectrum antibacterial activity, at a concentration of 80 microg/mL. The essential oils of Hypericum species showed antibacterial activity against the tested organisms and a yeast.
This study was conducted to increase total phenolics, flavonoids and hypericin accumulation in in vitro cultures of Hypericum retusum Aucher to determine the appropriate time of UV radiations. Proliferation of plantlets on Murashige-Skoog medium containing 0.5 mg L(- 1)N-6-benzylaminopurine was achieved under in vitro conditions. Then, the plantlets were exposed to UV-B radiation for different periods (15, 30, 45 and 60 min). The highest total phenolics, flavonoids and hypericin accumulation (43.17 ± 0.8; 35.09 ± 0.8; 2.7 ± 0.05 mg g(- 1), respectively) was achieved at 45 minutes of exposure to UV-B radiation when compared with the contents of naturally growing plants (23.33 ± 0.9, 18.62 ± 0.3 and 1.6 ± 0.01 mg g(- 1), respectively) and control groups (control group was not subjected to UV-B radiation).
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