Tadaaki Satou

Assay of nematocidal activity of isoquinoline alkaloids using third-stage larvae of Strongyloides ratti and S. venezuelensis.

We examined the effects of isoquinoline alkaloids in vitro in an effort to identify a treatment for Strongyloides stercoralis larva migrans in humans. Infective third-stage larvae of S. ratti and S. venezuelensis were used as model nematodes for S. stercoralis. Nematocidal activity was evaluated by the 50% paralysis concentration (PC(50)). Most of the tested isoquinoline alkaloids had activity for S. ratti and S. venezuelensis. We then evaluated in vitro cytotoxicity, which was the 50% inhibition concentration (IC(50)) of the compounds using HL60 tissue-culture cells. Three of the compounds (protopine, D-corydaline, and L-stylopine) which exhibited strong nematocidal activity, showed little cytotoxicity. In addition, we examined the relationship between nematocidal activity and cytotoxicity using the PC(50)/IC(50) ratio. A ratio equivalent to or lower than that calculated for the currently prescribed strongyloidosis treatments, ivermectin, albendazole and thiabendazole, was observed for allocryptopine, protopine, dehydrocorydaline, D-corydaline, L-stylopine, and papaverine. In contrast, the PC(50)/IC(50) ratios for protopine, D-corydaline, and L-stylopine were substantially more favorable. Therefore, protopine, D-corydaline, and L-stylopine were identified as potential effective treatments for strongyloidosis.

New apiose-containing triterpenoid saponins from Conyza blinii

Abstract Four new apiose-containing triterpenoid saponins, conyzasaponins D, E, F, and H, were isolated from the aerial parts of Conyza blinii . They are the first examples of triterpenoid saponins containing one apiose unit whose C-2 is substituted by a galactose. Conyzasaponins D and F have two apiose units, a sugar that has been rarely observed in natural products research. Their structures were established on the basis of extensive NMR studies and chemical degradation. Conyzasaponins D and F exhibited moderate cytotoxicity against HL-60 cell lines.

Twelve pregnane glycosides from Cynanchum atratum.

Eleven new 14,15-seco-pregnane-type steroidal glycosides, cynanosides P1-P5, Q1-Q3, R1-R3, and a novel 12,13-seco-14,18-nor-pregnane-type steroidal glycoside, cynanoside S, were isolated from the roots of Cynanchum atratum, together with four known compounds, atratoside C, sublanceoside E3, chekiangensoside C and cynatroside B. Their structures were determined on the basis of spectroscopic analysis and chemical evidence.

Organ accumulation in mice after inhalation of single or mixed essential oil compounds.

Essential oils are composed of multiple components. It is thought that the effect of essential oils is due to specific component ratios, which may differ from the original ratio when the essential oil is absorbed. However, very little detailed research exists in this area. We studied the distribution of essential oil components after inhalation of single and mixed components in mice. This research was done using four main components of Alpinia zerumbet (Pers.) B. L. Burtt. and R. M. Sm.: α‐pinene, p‐cymene, 1,8‐cineole, and limonene. After inhalation of single or mixed components for 90 min, component levels in the brain and liver of mice were measured. The results indicated that the amount of α‐pinene in the brain and liver was twofold greater after mixed‐component inhalation than that after single‐component inhalation. In a comparison of the components of the mixed inhalation, the ratio of α‐pinene increased to about three times that of 1,8‐cineole. It is thought that the absorption via the nasal mucus greatly influences this phenomenon. The results of this investigation of the bodily distribution of essential oil volatile components may provide clues for elucidating their action. Copyright

Nematocidal activities of thiabendazole and ivermectin against the larvae of Strongyloides ratti and S. venezuelensis

With the aim of developing therapeutic agents for strongyloidosis, the disease caused by infection with Strongyloides stercoralis, we established a novel assay technique using S. ratti and S. venezuelensis as models for S. stercoralis. The newly developed assay technique was found to more accurately represent treatment-induced larval paralysis than existing assays. Our method uses paper disks impregnated with the test solution, which even allows materials that are sparingly soluble in water to be tested. An inverted microscope was used to observe the larval states, and these states were recorded using a digital camera. We observed the activities of ivermectin and thiabendazole against larvae and calculated larval motility and velocity. These two factors were then combined to determine the overall viability of larvae at selected concentrations. The activities of the anthelmintics were compared by calculating the concentrations at which 50% viability was demonstrated, or in other words, the concentration at which paralysis was caused in 50% of the individuals (50% paralysis concentration; PC(50)). Evaluations after 24h of exposure yielded the following reproducible PC(50) values for ivermectin and thiabendazole, respectively: S. ratti, 2.4 and 140 microM; and S. venezuelensis, 2.3 and 190 microM. After treatment with ivermectin, there was a tendency for larval motility to be greater than that of the controls at low concentrations, a result that might be associated with its mechanism of action.

Triterpenoid saponins from Impatiens siculifer.

Triterpenoid saponins, impatienosides A-G, together with 12 known saponins, were isolated from the whole plants of Impatiens siculifer. Their structures were established on the basis of extensive 1D and 2D NMR and MS analyses coupled with chemical degradation. Cytotoxic activities of the isolated saponins were evaluated against three human cancer cell lines: human myeloid leukemia HL-60 cells, human stomach KATO-III adenocarcinoma, and human lung A549 adenocarcinoma.

Expression of BDNF and TH mRNA in the Brain Following Inhaled Administration of α-Pinene

Essential oils are mainly administered by inhalation. Administration by inhalation is considered to occur through two pathways, neurological transfer and pharmacological transfer. However, the relationship between the two routes is not clear. To clarify this relationship, we administered α‐pinene, which has an anxiolytic‐like effect, to mice. Emotional behavior and accumulation and expression of relevant mRNAs in the brain (brain‐derived neurotrophic factor (BDNF); tyrosine hydroxylase (TH)) were examined following inhaled administration of α‐pinene (10 μL/L air for 60 or 90 min). To evaluate the anxiolytic‐like effect, the elevated plus maze (EPM) test was used. Inhalation of α‐pinene for 60 min produced a significant increase in the total distance traveled in the EPM test compared with control (water). The concentration of α‐pinene in the brain after 60 min of inhalation was significantly increased compared with that after 90 min of inhalation. The expression of BDNF mRNA in the olfactory bulb and in the hippocampus was almost the same after 60 min of inhalation compared to that after 90 min of inhalation. The expression of TH mRNA in the midbrain after 60 min of inhalation was significantly increased compared with that of the control. Thus, an increase in α‐pinene in the brain induces an increase in TH mRNA expression and increases locomotor activity. The anxiolytic‐like effect may be related to both neurological transfer and pharmacological transfer. Copyright

Relationship Between Emotional Behavior in Mice and the Concentration of (+)-α-Santalol in the Brain.

We previously reported finding anxiolytic‐like activity for sandalwood oil after administration in mice. In this report, we further investigated the emotional behavior associated with inhaled or intraperitoneally administered (+)‐α‐santalol, the main component of sandalwood oil, in addition to examining whether pharmacological or neurological transfers are responsible for this behavior. After administration of (+)‐α‐santalol by inhalation or intraperitoneal injection, we assessed anxiolytic‐like and locomotor activities using elevated‐plus maze tests. We also examined the relationship between the emotional behavior and the (+)‐α‐santalol brain concentration.

The essential oil of Mongolian Nepeta sibirica: a single component and its biological activities

Nepeta sibirica L. has been used for the treatment of various diseases and is one of the traditional medicines of Mongolia. The essential oil of N. sibirica was shown to contain a single component by gas chromatography–mass spectrometry (GC–MS) analysis. The optical rotation and nuclear magnetic resonance (NMR) analyses demonstrated that the component was 4aα,7α,7aα-nepetalactone. This essential oil, that is, 4aα,7α,7aα-nepetalactone, showed antimicrobial activity against Staphylococcus aureus, Escherichia coli, Candida albicans and Aspergillus fumigatus. Cell cytotoxicity testing showed that the nepetalactone was cytotoxic to HL60 myeloma and Kato III stomach carcinoma cell lines. The essential oil of this Mongolian N. sibirica is useful for researching the bioactivity of nepetalactone, which has been difficult to prepare.

Differences in the effects of essential oil from Citrus junos and (+)-limonene on emotional behavior in mice

Citrus junos (Yuzu, CJ) is a traditional fruit in Japan and its essential oil (EO) has been used in food, cosmetics, and traditional medicine. The present study examined the influence of essential oil from Citrus junos (EOCJ) on emotional behavior in mice, and how its action differed in comparison to (+)-limonene (LI), its major component. The influence of inhaled administration (i.h.) of EOCJ for 90 minutes on mouse emotional behavior was examined using the light/dark box (LDB) test, open field (OF) test, and elevated plus-maze (EPM) test. In addition, gas chromatography (GC) was used in clarifying the amount of LI absorbed in the internal organs. Inhalation of EOCJ at 3.4 and 6.7 mg/L air indicated the tendency for an anxiolytic-like effect in LDB and EPM tests. In addition, an increase in locomotor activity was observed at 6.7 mg/L air EOCJ (i.h.) in the OF test. Inhalation of (+)-LI at 3.4 and 6.7 mg/L air indicated the same anxiolytic-like effect in EPM test as with EOCJ. In contrast, the anxiolytic-like effect of (+)-LI was smaller than that of EOCJ in the LDB test. Furthermore, an increase in locomotor activity was not observed at 6.7 mg/L air (+)-LI (i.h.).