(S)-4--5-7-Trihydroxy-6-prenylflavanone and xanthohumol

For the prenylated hops phenols 6- and 8-prenylnaringenin (1 and 2), xanthohumol (3), and isoxanthohumol (4), a variety of biological activities has been described. In the current study, a transwell based in vitro model using the human intestinal epithelial cell line Caco-2 was developed to assess potential beneficial effects of compounds 1-4 on TNF-α-induced impairment of tight junction (TJ) permeability. Transepithelial electrical resistance (TEER) was measured using the latest cellZScope online monitoring device. TNF-α treatment (25 ng/mL) induced a significant decrease in TEER values (204.71 ± 4.57 at 72 h) compared to that in control values (245.94 ± 1.68 at 72 h). To determine preventive effects on TNF-α-induced impairment of TJ permeability, 1-4 were added to the apical compartment of Caco-2 monolayers 1 h before TNF-α treatment; afterward, TNF-α was added to the basolateral compartment to induce TJ dysfunction and incubated for a further 72 h. Using this setting, only 1 and 2 prevented epithelial disruption induced by TNF-α. To evaluate restorative effects of 1-4, TNF-α was added to the basolateral compartment of Caco-2 cell monolayers. After 48 h of incubation, 1-4 were added to the apical side, and TEER values were monitored online for a further 72 h. Under these experimental conditions, only 2 restored TNF-α induced barrier dysfunction.

Topics: Caco-2 Cells; Cell Survival; Epithelial Cells; Flavanones; Flavonoids; Humans; Humulus; Interferon-alpha; Intestinal Mucosa; Molecular Structure; Permeability; Phenols; Prenylation; Propiophenones; Tight Junctions; Tumor Necrosis Factor-alpha; Xanthones

Botanical dietary supplements contain multiple bioactive compounds that target numerous biological pathways. The lack of uniform standardization requirements is one reason that inconsistent clinical effects are reported frequently. The multifaceted biological interactions of active principles can be disentangled by a coupled pharmacological/phytochemical approach using specialized ("knock-out") extracts. This is demonstrated for hops, a botanical for menopausal symptom management. Employing targeted, adsorbent-free countercurrent separation, Humulus lupulus extracts were designed for pre- and postmenopausal women by containing various amounts of the phytoestrogen 8-prenylnaringenin (8-PN) and the chemopreventive constituent xanthohumol (XH). Analysis of their estrogenic (alkaline phosphatase), chemopreventive (NAD(P)H-quinone oxidoreductase 1 [NQO1]), and cytotoxic bioactivities revealed that the estrogenicity of hops is a function of 8-PN, whereas their NQO1 induction and cytotoxic properties depend on XH levels. Antagonization of the estrogenicity of 8-PN by elevated XH concentrations provided evidence for the interdependence of the biological effects. A designed postmenopausal hop extract was prepared to balance 8-PN and XH levels for both estrogenic and chemopreventive properties. An extract designed for premenopausal women contains reduced 8-PN levels and high XH concentrations to minimize estrogenic while retaining chemopreventive properties. This study demonstrates the feasibility of modulating the concentrations of bioactive compounds in botanical extracts for potentially improved efficacy and safety.

Topics: Dietary Supplements; Estrogens; Female; Flavanones; Flavonoids; Humans; Humulus; Molecular Structure; Phytoestrogens; Propiophenones; Women's Health