In a study published recently in the International Journal of Molecular Medicine, researchers associated with several institutes and universities in South Korean investigated the action of a Humulus japonicus extract in test mice who had been induced with rhematoid arthritis like symptoms.
Longtime constituent of Asian herbal medicines
Humulus japonicus, or Japanese hops (also known as wild hops), is a member of of the hemp family native to East Asia. It has been imported to the United States as an ornamental and is now endemic in eastern North America where it is considered to be an invasive species.
Japanese hops has long been a raw material used in traditional Asian herbal medicines. It is purported to have anti‐oxidative, anti‐microbial, and anti‐inflammatory effects.
In at least one case, the botanical was also investigated for its antiobesity effects. In another Korean study published in 2018, researchers claimed an aqueous extract of the herb ameliorated hyperlipidemia and markers of non alcoholic fatty liver disease in a test group of obese mice.
In the most recent study, the researchers used an ethanolic extract of the botanical, which was prepared by Korea Bioactive Natural Material Bank. The dried aerial parts of a verified lot of material were soaked in 70% ethanol for two days to obtain the test material.
Arthritis induced with collagen injections
The test mice were induced with symptoms mimicing rhematoid arthritis via seveal injectsion of bovine collagen Type II. The degree of the symptoms were measured via paw swelling.
The mice were immunized iwth the collagen at day 1 and 21. The oral treatment with the test exttract at a dose of 300 mg/kg began three days before the second injection, and continued through day 35, the last day of the study, when the mice were euthanized. The control group of mice were fed a substitute vehicle.
In addition to measuring paw swelling in the living mice, the rear paws of the animals were collected at the end of the experiment. The paws were cut into sections and analyzed for signs of joint soft tissue and bone damage.
The researchres found that the HJ extract-treated mice showed less soft tissue damage in their hind paws and less swelling in both sets of paws. In addition, those mice showed lower levels of pro inflammatory mediators than did the control group mice.
“[T]o the best of our knowledge, this is the first study to suggest that HJ has protective effects on the inflam‐ mation and destruction of cartilage and bones during the development of RA in CIA mice by inhibiting the secretion of pro‐inflammatory mediators and osteoclast formation,” the researchers concluded.
Source: International Journal of Molecular Medicine
Humulus japonicus extract ameliorates collagen‐induced arthritis in mice through regulation of overall articular inflammation
Authors: Kang EJ, et al.