2022 Volume 9 Issue 4 Pages 221-227
Kuromoji (Lindera umbellata Thunb.) is a deciduous shrub of the camphoraceae family endemic to Japan. It has long been used as an ingredient for tea and essential oil, and its dried trunk branches have been used as an ingredient for medicinal drinks as "Usho," a crude drug with stomachic actions. This paper describes the antiglycative and antiviral activities of a non-volatile extract of kuromoji extract (KE), which we have recently revealed. In absorption and metabolism studies, KE was found to have inhibitory activity against the formation of advanced glycation endproducts (AGEs). AGEs accumulate between collagen fibers in the bone matrix, thus reducing bone strength, and studies using bone glycation samples suggest that KE may ameliorate the reduction in bone strength caused by glycation. Furthermore, an 8-week oral administration of KE to streptozotocin-induced diabetic rats showed that it suppressed renal inflammation in diabetic nephropathy. The antiviral action of KE was confirmed by plaque assay to act against influenza viruses even after infection and to inhibit viral growth. The TCID50 assay showed that KE has antiviral activity against adenovirus and enterovirus, which are viruses that cause colds, as well as new strains of influenza virus and their drug-resistant strains, confirming that the antiviral activity of KE has a wide spectrum of action. A randomized, double-blind, placebo-controlled, parallel-group comparative study on the effects of taking KE-containing candies showed a reduction in the incidence of influenza and in the symptomatic period of cold symptoms. KE is expected to develop as a functional food material unique to Japan in the future because of its various functionalities as described above due to its antiglycative and antiviral effects.
