Posted on February 25, 2008. Filed under: Research | Tags: activities, agent, anti, hop, humulus, infective, lupulus, metabolites, potential, Xanthohumol, XN |
-
-
Broad spectrum anti-infective potential of xanthohumol from hop (Humulus lupulus L.) in comparison with activities of other hop constituents and xanthohumol metabolites.
Division of Toxicology and Cancer Risk Factors, German Cancer Research Center, Heidelberg, Germany. c.gerhauser@dkfz.de
This review summarizes the capacity of xanthohumol (XN) in comparison with additional hop constituents and metabolites to act as an antiinfective agent against microorganisms including bacteria, viruses, fungi and malarial protozoa. XN was shown to inhibit the Gram-positive bacteria Staphylococcus aureus and Streptococcus mutans. Antiviral activity was demonstrated against bovine viral diarrhea virus, cytomegalovirus, herpes simplex virus type 1 and 2 and human immunodeficiency virus 1. Inhibition of two Trichophyton spp. was indicative of antifungal activity. Finally, XN potently inhibited the replication of Plasmodium falciparum, the causative agent of malaria. This effect was linked to the inhibition of glutathione-mediated degradation and detoxification of haemin, a by-product of the parasitic digestion of haemoglobin. Overall, these activities further contribute to the broad spectrum of biological effects observed with XN.
PMID: 16092071 [PubMed – indexed for MEDLINE]
Read Full Post |
Make a Comment ( None so far )
Posted on February 15, 2008. Filed under: Research | Tags: agents, anti, cancer, chemistry, chemo, damage, DNA, humulus, induction, inhibitor, lupulus, medicinal, pharmacognosy, preventive, University of Illinois at Chicago, Xanthohumol, XH, XN |
1: Chem Res Toxicol. 2005 Aug;18(8):1296-305.
Xanthohumol isolated from Humulus lupulus Inhibits menadione-induced DNA damage through induction of quinone reductase.
Dietz BM,
Kang YH,
Liu G,
Eggler AL,
Yao P,
Chadwick LR,
Pauli GF,
Farnsworth NR,
Mesecar AD,
van Breemen RB,
Bolton JL.
Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, M/C 781, Chicago, Illinois 60612-7231, USA.
The female parts of hops (Humulus lupulus L.) show estrogenic effects as well as cancer chemopreventive potential. We analyzed the chemopreventive mechanism of hops by studying its antioxidative activities and its effect on the detoxification of a potentially toxic quinone (menadione). The detoxification enzyme quinone reductase [(NAD(P)H:quinone oxidoreductase, QR] protects against quinone-induced toxicity and has been used as a marker in cancer chemoprevention studies. Although the hop extract was only a weak quencher of free radicals formed from 1,1-diphenyl-2-picrylhydrazyl, it demonstrated strong QR induction in Hepa 1c1c7 cells. In addition, compounds isolated from hops including xanthohumol (XH) and 8-prenylnaringenin were tested for QR induction. Among these, XH was the most effective at inducing QR with a concentration required to double the specific activity of QR (CD value) of 1.7 +/- 0.7 microM. In addition, pretreatment of Hepa1c1c7 cells with XH significantly inhibited menadione-induced DNA single-strand breaks. The QR inhibitor dicumarol reversed the protective effect of XH against menadione-induced DNA damage. Because the expression of QR and other detoxifying enzymes is known to be upregulated by binding of the transcription factor Nrf2 to the antioxidant response element (ARE), the reporter activity mediated by ARE in HepG2-ARE-C8 cells was investigated after incubation with XH for 24 h. Under these conditions, XH increased ARE reporter activity in a dose-dependent manner. One mechanism by which XH might induce QR could be through interaction with Keap1, which sequesters Nrf2 in the cytoplasm, so that it cannot activate the ARE. Using LC-MS-MS, we demonstrated that XH alkylates human Keap1 protein, most likely on a subset of the 27 cysteines of Keap1. This suggests that XH induces QR by covalently modifying the Keap1 protein. Therefore, XH and hops dietary supplements might function as chemopreventive agents, through induction of detoxification enzymes such as QR.
PMID: 16097803 [PubMed – indexed for MEDLINE]
Read Full Post |
Make a Comment ( None so far )
Posted on February 14, 2008. Filed under: Research | Tags: beer, cholesterol, diabetes, fatty acides, genes, gluconegenetic, glucose, Hops, humulus, lupulus, metabolism, PubMed, Xanthohumol, XN |
-
-
Xanthohumol, the chalcone from beer hops (Humulus lupulus L.), is the ligand for farnesoid X receptor and ameliorates lipid and glucose metabolism in KK-A(y) mice.
R&D Laboratory, Functional Food Division, Kirin Brewery Co., Ltd., 3 Miyahara, Takasaki, Gunma 370-1295, Japan. h-nozawa@kirin.co.jp
We have examined the modulating action of xanthohumol (XN) on the farnesoid X receptor (FXR) in vitro and in vivo. In the transient transfection assay, XN dose-dependently increased the BSEP promoter-driven luciferase activity. XN-fed KK-A(y) mice exhibited lowered levels of plasma glucose, plasma, and hepatic triglyceride. They also showed decreased amounts of water intake, lowered weights of white adipose tissue, and exhibited increased levels of plasma adiponectin, indicating that XN attenuated diabetes in KK-A(y) mice. The hepatic gene expression of XN-fed mice showed lowered levels of SREBP-1c including its targets involved in fatty acid synthesis and lowered levels of gluconeogenetic genes. However, the expression of cholesterol 7-hydroxylase (CYP7A1) was significantly induced in the liver of XN-fed mice. From the present results, it is suggested that XN acts on FXR through a selective bile acid receptor modulator (SBARM) like guggulsterone or polyunsaturated fatty acids, which have previously been reported as SBARMs.
PMID: 16140264 [PubMed – indexed for MEDLINE]
Read Full Post |
Make a Comment ( 4 so far )
One Molecule (XN) is About to Change Your World (English & Korean) 