Humulone

Humulone suppresses replication of respiratory syncytial virus and release of IL-8 and RANTES in normal human nasal epithelial cells.[Pubmed:23381605]

Med Mol Morphol. 2013 Dec;46(4):203-9.

Respiratory syncytial virus (RSV) is the major infectious agent causing serious respiratory tract inflammation in infants and young children. However, an effective vaccine and anti-viral therapy for RSV infection have not yet been developed. Hop-derived bitter acids have potent pharmacological effects on inflammation. Therefore, we investigated the effects of Humulone, which is the main constituent of hop bitter acids, on the replication of RSV and release of the proinflammatory cytokine IL-8 and chemokine RANTES in RSV-infected human nasal epithelial cells (HNECs). We found that Humulone prevented the expression of RSV/G-protein, formation of virus filaments and release of IL-8 and RANTES in a dose-dependent manner in RSV-infected HNECs. These findings suggest that Humulone has protective effects against the replication of RSV, the virus assembly and the inflammatory responses in HNECs and that it is a useful biological product for the prevention and therapy for RSV infection.

Humulone inhibits phorbol ester-induced COX-2 expression in mouse skin by blocking activation of NF-kappaB and AP-1: IkappaB kinase and c-Jun-N-terminal kinase as respective potential upstream targets.[Pubmed:17372274]

Carcinogenesis. 2007 Jul;28(7):1491-8.

Humulone, a bitter acid derived from hop (Humulus lupulus L.), possesses antioxidative, anti-inflammatory and other biologically active activities. Although Humulone has been reported to inhibit chemically induced mouse skin tumor promotion, the underlying mechanisms are yet to be elucidated. Since an inappropriate over-expression of cyclooxygenase-2 (COX-2) is implicated in carcinogenesis, we investigated effects of Humulone on COX-2 expression in mouse skin stimulated with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Topical application of Humulone (10 mumol) significantly inhibited TPA-induced epidermal COX-2 expression. Humulone also diminished TPA-induced DNA binding of nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1). Pre-treatment with Humulone attenuated TPA-induced phosphorylation of p65 and nuclear translocation of NF-kappaB subunit proteins. Humulone blunted TPA-induced activation of inhibitory kappaB (IkappaB) kinase (IKK) in mouse skin, which accounts for its suppression of phosphorylation and subsequent degradation of IkappaBalpha. An in vitro kinase assay revealed that Humulone could directly inhibit the catalytic activity of IKKbeta. Humulone suppressed the activation of mitogen-activated protein kinases (MAPKs) in TPA-treated mouse skin. The roles of extracellular signal-regulated protein kinase-1/2 and p38 MAPK in TPA-induced activation of NF-kappaB in mouse skin had been defined in our previous studies. The present study revealed that topical application of SP600125, a pharmacological inhibitor of c-Jun-N-terminal kinase (JNK), abrogated the activation of AP-1 and the expression of COX-2 in TPA-treated mouse skin. Taken together, Humulone suppressed TPA-induced activation of NF-kappaB and AP-1 and subsequent expression of COX-2 by blocking upstream kinases IKK and JNK, respectively, which may account for its antitumor-promoting effects on mouse skin carcinogenesis.

Inhibition of angiogenesis by humulone, a bitter acid from beer hop.[Pubmed:11708802]

Biochem Biophys Res Commun. 2001 Nov 23;289(1):220-4.

On the basis of our previous finding that Humulone, a bitter acid from beer hop extract, was a potent inhibitor of bone resorption and inhibited the catalytic activity of cyclooxygenase-2 (COX-2) and more potently the transcription of the COX-2 gene, we examined the effect of Humulone on angiogenesis, using chick embryo chorioallantoic membranes (CAMs) and vascular endothelial and tumor cells. Humulone significantly prevented in vivo angiogenesis in CAM in a dose-dependent manner with an ED(50) of 1.5 microg/CAM. Humulone also inhibited in vitro tube formation of vascular endothelial cells. Moreover, it suppressed the proliferation of endothelial cells and the production of vascular endothelial growth factor (VEGF), an angiogenic growth factor, in endothelial and tumor cells. Thus, Humulone is a potent angiogenic inhibitor, and may be a novel powerful tool for the therapy of various angiogenic diseases involving solid tumor growth and metastasis.

Induction of differentiation of myelogenous leukemia cells by humulone, a bitter in the hop.[Pubmed:9680110]

Leuk Res. 1998 Jul;22(7):605-10.

The active form of vitamin D, 1alpha,25-dihydroxyvitamin D3 (VD3), inhibits proliferation and induces differentiation of myelomonocytic leukemia cells, but its clinical use is limited by the adverse effect of hypercalcemia. VD3 mobilizes calcium stores from bone by inducing the dissolution of bone mineral and matrix. We have recently found that Humulone, a bitter in the hop extract for beer brewing, effectively inhibits bone resorption. In this study we examined the effect of Humulone on the differentiation of human myelogenous leukemia cells. Humulone alone inhibited the growth of monoblastic leukemia U937 cells while only slightly increasing differentiation markers such as nitroblue tetrazolium (NBT)-reducing and lysozyme activities. Humulone effectively enhanced the differentiation-inducing action of VD3. Other myelomonocytic leukemia cells were induced to differentiate by VD3 and this was also enhanced by Humulone. Since Humulone is a less-toxic inhibitor of bone resorption, the combination of Humulone and VD3 may be useful in differentiation therapy of myelomonocytic leukemia.