Crude ethanolic extracts from Phlomis viscosa Poiret leaves from the Judea region (Israel) are renowned for their remarkable geroprotective properties: anti-inflammatory, anti-diabetic, and anti-cancer. A phytochemical investigation carried out in this study revealed that the tested plant might belong to a particular distinct chemotype because its phytochemicals are different from compounds that were mentioned in the literature. Among the compounds identified by us was diosmin, the synthetic derivatives of which were further obtained and investigated. In particular, activities of the isolated compounds and synthesized diosmin derivatives were assessed. Our results revealed that the following compounds significantly lessened secretion of some pro-inflammatory cytokines: diosmin, himachala-2-diene, and 5,7-dihydroxy-2-(3-hydroxy-4-methoxyphenyl) chromen-4-one. In addition, diosmin, synthesized diosmin derivatives, and some identified terpenes were found to have anti-diabetic activities. A significant anti-cancer effect of the whole extract on U-87 (human glioblastoma carcinoma cells line) and MCF7 (human breast carcinoma cell line) was also demonstrated, and it was better than that of DOX (doxorubicin). Collectively, the results obtained in the in vitro models suggest a wide spectrum of beneficial bioactivities of the extract and its active compounds.
Keywords: anti-cancer; anti-diabetic; anti-inflammatory; diosmetin; diosmin.