The Promising Ability of Humulus lupulus L. Iso-α-acids vs. Diabetes, Inflammation, and Metabolic Syndrome: A Systematic Review

Abstract

For centuries, natural medicines have represented the only option for treating human diseases and, nowadays, plant phytochemicals are considered as promising compounds to treat or prevent chronic conditions. Among them, hop flowers (Humulus lupulus L.), typically used in brewing industries to give the typical aroma and flavor to beer, have attracted particular attention for their health promoting properties. Several in vivo/vitro studies and human interventional trials have demonstrated the beneficial effects of these molecules on weight gain, lipid metabolism, glucose homeostasis, insulin sensitivities, and inflammation by acting on different targets. All these activities suggest a possible role of bitter hop acid in preventing metabolic syndrome and its related diseases. A systematic quest on PubMed and Scopus databases was performed to identify pre-clinical and clinical studies focusing on this topic. This systematic review summarizes the results obtained by different cell lines, animal models, and human interventional trials to propose iso-α-acids as medical nutrition therapy to treat or prevent metabolic syndrome and its related disorders as diabetes, dislipidemia inflammation, etc.

Anti‐Inflammatory Markers of Hops Cultivars (Humulus lupulus L.) Evaluated by Untargeted Metabolomics Strategy

“…Humulones and the other bitter acids are susceptible to a natural isomerization process, by light exposure, use of boiling methods or hops extraction using an aqueous medium of increased pH (7.5–8.5), thus resulting in the formation of iso‐α‐acids [7,12] . In addition, these compounds have been increasingly reported in the literature as some of the main anti‐inflammatory agents in hops, [6,33,36–38] which also corroborate our findings. Nozawa et al.…”

“…The prenylated phloroglucinol homologs, humulone, cohumulone and adhumulone and its respective isomerized homologs are the main α‐acids found in different hop cultivars according to literature data [32] . Studies have shown that these compounds display potent anti‐inflammatory activity, through PGE2 inhibition by in vitro and in vivo models, [6,33] which corroborate our findings. The humulone was reported in the literature as a potent inhibitor on the 12‐ O ‐tetradecanoylphorbol‐13‐acetate (TPA)‐induced ear oedema anti‐inflammatory model when compared to the steroidal anti‐inflammatory drug hydrocortisone and the nonsteroidal indomethacin [34] .…”

“…Humulones and the other bitter acids are susceptible to a natural isomerization process, by light exposure, use of boiling methods or hops extraction using an aqueous medium of increased pH (7.5 -8.5), thus resulting in the formation of iso-α-acids. [7,12] In addition, these compounds have been increasingly reported in the literature as some of the main antiinflammatory agents in hops, [6,33,[36][37][38] which also corroborate our findings. Nozawa et al (2005) [6] has evidenced a dose-dependent effect by a decrease of PGE2 levels in the colonic mucosa of azoxymethanetreated with isomerized hop extract, and also in RAW264.7 cells induced by LPS/interferon agents.…”

Hops (Humulus lupulus L.) as a Novel Multipurpose Crop for the Mediterranean Region of Europe: Challenges and Opportunities of Their Cultivation

“…Recently, treatment with iso-α-acid extracted from hops was found to soothe or prevent different ailments such as liver steatosis, inflammation, and fibrosis as well as metabolic disorders such as obesity and diabetes ( [43,44], and reference therein).…”

Establishment of an Efficient Micropropagation System for Humulus lupulus L. cv. Cascade and Confirmation of Genetic Uniformity of the Regenerated Plants through DNA Markers

“…Furthermore, recent reports have highlighted the antiproliferative, anticancer [9,10], antiinflammatory [11,12] and antimicrobial [13] properties of hops due to the presence of phenolic compounds including terpenes, humulones (α-acids), lupulones (β-acids) and prenylated flavonoids secreted by lupulin glands [13]. For example, treatments with isoα-acids extracted from hops proved to be efficient in relieving the symptoms of various diseases such as liver steatosis and fibrosis, as well as obesity and diabetes [14,15].…”