Flavonoids isolated from the flowers of Pulsatilla flavescens and their anti-piroplasm activity

Journal of Natural Medicines - Pulsatilla species are known as “Yargui”, and their flowers are traditionally used in Mongolia as a tonic and for the treatment of inflammatory diseases....     

A Novel Topoisomerase Inhibitor, Daurinol, Suppresses Growth of HCT116 Cells with Low Hematological Toxicity Compared to Etoposide

We report that daurinol, a novel arylnaphthalene lignan, is a promising potential anticancer agent with adverse effects that are less severe than those of etoposide, a clinical anticancer agent. Despite its potent antitumor activity, clinical use of etoposide is limited because of its adverse effects, including myelosuppression and the development of secondary leukemia. Here, we comprehensively compared the mechanistic differences between daurinol and etoposide because they have similar chemical structures. Etoposide, a topoisomerase II poison, is known to attenuate cancer cell proliferation through the inhibition of DNA synthesis. Etoposide treatment induces G₂/M arrest, severe DNA damage, and the formation of giant nuclei in HCT116 cells. We hypothesized that the induction of DNA damage and nuclear enlargement due to abnormal chromosomal conditions could give rise to genomic instability in both tumor cells and in actively dividing normal cells, resulting in the toxic adverse effects of etoposide. We found that daurinol is a catalytic inhibitor of human topoisomerase IIa, and it induces S-phase arrest through the enhanced expression of cyclins E and A and by activation of the ATM/Chk/Cdc25A pathway in HCT116 cells. However, daurinol treatment did not cause DNA damage or nuclear enlargement in vitro. Finally, we confirmed the in vivo antitumor effects and adverse effects of daurinol and etoposide in nude mice xenograft models. Daurinol displayed potent antitumor effects without any significant loss of body weight or changes in hematological parameters, whereas etoposide treatment led to decreased body weight and white blood cell, red blood cell, and hemoglobin concentration.     

Surveillance and characterization of avian influenza viruses from migratory water birds in eastern Hokkaido, the northern part of Japan, 2009–2010

Avian influenza virus (AIV) surveillance was conducted around a small pond in Obihiro, eastern Hokkaido, Japan. Eleven AIVs were isolated from a total of 1,269 fecal samples of migratory wild birds collected during 2009 and 2010. The sample number covered approximately 60 % of the total number of birds observed during sampling periods. The subtypes of the isolates included H3N8 (4 isolates), H5N2 (3), H6N2 (2), H6N1 (1), and H11N2 (1). The H3N8 subtype was most prevalent as in the previous studies performed in Hokkaido. The three H5N2 isolates genetically characterized as low pathogenic AIV were closely related to the strains previously isolated from aquatic wild birds in Japan and also to the Korean strains isolated from aquatic birds in recent years. In Korea, H5N2 subtype virus has often been isolated from poultry and wild birds, as well as reassortant viruses generated from duck H5N2 viruses and chicken H9N2 virus, and avian-swine-like reassortant H5N2 viruses. Considering the previous chicken outbreaks caused by highly pathogenic H5N2 viruses, which affected many countries, it should be an important priority to continue, monitoring the evolution of H5N2 viruses circulating in the region.     

The SARS-CoV-2-Inactivating Activity of Hydroxytyrosol-Rich Aqueous Olive Pulp Extract (HIDROX®) and Its Use as a Virucidal Cream for Topical Application

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally. Although measures to control SARS-CoV-2, namely, vaccination, medication, and chemical disinfectants are being investigated, there is an increase in the demand for auxiliary antiviral approaches using natural compounds. Here we have focused on hydroxytyrosol (HT)-rich aqueous olive pulp extract (HIDROX^®) and evaluated its SARS-CoV-2-inactivating activity in vitro. We showed that the HIDROX solution exhibits time- and concentration-dependent SARS-CoV-2-inactivating activities, and that HIDROX has more potent virucidal activity than pure HT. The evaluation of the mechanism of action suggested that both HIDROX and HT induced structural changes in SARS-CoV-2, which changed the molecular weight of the spike proteins. Even though the spike protein is highly glycosylated, this change was induced regardless of the glycosylation status. In addition, HIDROX or HT treatment disrupted the viral genome. Moreover, the HIDROX-containing cream applied on film showed time- and concentration-dependent SARS-CoV-2-inactivating activities. Thus, the HIDROX-containing cream can be applied topically as an antiviral hand cream. Our findings suggest that HIDROX contributes to improving SARS-CoV-2 control measures.     

The chemopreventive effects of Saussurea salicifolia through induction of apoptosis and phase II detoxification enzyme

The ethanol extract of the aerial part of the Mongolian medicinal plant Saussurea salicifolia induced a dose-dependent cell growth inhibition in both human gastric adenocarcinoma AGS cells and mouse hepatoma Hepa 1c1c7 cells (IC(50)=30.22 and 116.96 mug/ml), respectively. The extract induced an apoptosis in AGS cells inference from the externalization of the phosphatidylserine, the increase of the sub G0/G1 content (%) and the apoptotic morphological changes including membrane blebbing, the formation of apoptotic bodies and chromatin condensation. In order to identify active substances causing the apoptosis, we further isolated major compounds present in Saussurea salicifolia and 7 compounds were isolated including a sesquiterpene lactone, cynaropicrin, 3 lignans (trachelogenin, matairesinol and arctigenin) and 3 lignan glycosides (tracheloside, matairesinoside and arctiin). In general the lignan aglycones were more cytotoxic than their lignan glycosides in both AGS cells and Hepa 1c1c7 cells. Cynaropicrin not only showed the most potent cytotoxicity among the 7 major compounds but also it induced an apoptosis and a weak G2/M arrest in AGS cells. Arctigenin had the second-best cytotoxicity among 7 major compounds, and induced an apoptosis. In order to evaluate the induction of the phase II detoxification enzyme, we measured the induction of quinone reductase activity of the extract, fractions and compounds in Hepa 1c1c7 cells. The ethyl acetate fraction and arctigenin showed the strongest cancer chemopreventive activity (chemoprevention index=9.88 and 7.57, respectively). These data suggest that the extract as well as the lignan compounds (especially arctigenin) originated from Saussurea salicifolia may be served as potential cancer chemopreventive agents for prevention or treatment of human cancers.