Therapeutic effects of the alkaline extract of leaves of Sasa sp. and elucidation of its mechanism in acute kidney injury.

Acute kidney injury (AKI), a common complication in hospitalized patients, is associated with high morbidity and mortality rates. However, there are currently no approved or effective therapeutics for AKI. AKI is primarily caused by ischemia/reperfusion (I/R) injury, with oxidative stress from reactive oxygen species (ROS) being a major contributor. This study aimed to evaluate the efficacy of an alkaline extract of the leaves of Sasa sp. (SE) using mouse renal I/R injury and hypoxia/reoxygenation (H/R) models in NRK-52E cells. Renal function parameters were measured, and histopathological evaluations were performed to assess the efficacy of SE. In addition, to determine the mechanisms underlying the effects of SE on renal I/R injury, its effects on malondialdehyde (MDA) of oxidative stress and interleukin (IL)-6 and IL-1ß of inflammatory cytokines were evaluated. SE (0.03, 0.3, and 3 g/kg) improved renal function in a dose-dependent manner. In addition, SE ameliorated tubular injury and, reduced IL-6, IL-1ß and MDA. Also, SE ameliorated cell death, ROS production, and inflammatory cytokine production in H/R-exposed NRK-52E cells. SE showed antioxidant and anti-inflammatory activities in the AKI. These results indicate the potential of SE as a medicinal compound for the prevention and treatment of AKI.

Quantification of the Ability of Natural Products to Prevent Herpes Virus Infection.

Background: Herpes simplex virus (HSV) is usually dormant and becomes apparent when body conditions decline. We investigated the anti-HSV activity of various natural and synthetic compounds for future clinical application. Methods: Mock- and HSV-infected Vero cells were treated for three days with various concentrations of samples. For short exposure, 100-fold concentrated virus were preincubated for 3 min with samples, diluted to normal multiplicity of infection (MOI), before the addition to the cells. Anti-HSV activity was evaluated by the chemotherapy index. Results: Alkaline extracts of the leaves of Sasa sp. (SE) and pine cone (PCE) showed higher anti-HSV activity than 20 Japanese traditional herb medicines (Kampo formulas), four popular polyphenols, and 119 chromone-related compounds. Exposure of HSV to SE or PCE for 3 min almost completely eliminated the infectivity of HSV, whereas much longer exposure time was required for Kakkonto, the most active Kampo formulae. Anti-HSV activity of PCE and Kakkonto could be detected only when they were dissolved by alkaline solution (pH 8.0), but not by neutral buffer (pH 7.4). Anti-HSV activity of SE and povidone iodine was stable if they were diluted with neutral buffer. Conclusions: The present study suggests the applicability of SE and PCE for treatment of oral HSV and possibly other viruses.

Search of Neuroprotective Polyphenols Using the "Overlay" Isolation Method.

Previous studies of the neuroprotective activity of polyphenols have used ununiform culture systems, making it difficult to compare their neuroprotective potency. We have established a new and simple method for preparing differentiated PC12 cells by removing the toxic coating step. Cells were induced to differentiate with the nerve growth factor (NGF) in a serum-free medium, without a medium change, but with a one-time overlay supplementation of NGF. The optimal inoculation density of the cells was 6⁻12 × 10³ cells/cm², and the presence of serum inhibited the differentiation. Neuroprotective activity could be quantified by the specific index (SI) value, that is, the ratio of the 50% cytotoxic concentration to the 50% effective concentration. Alkaline extract from the leaves of Sasa senanensis Rehder (SE), having had hormetic growth stimulation, showed the highest SI value, followed by epigallocatechin gallate. The SI value of curcumin and resveratrol was much lower. This simple overly method, that can prepare massive differentiated neuronal cells, may be applicable for the study of the differentiation-associated changes in intracellular metabolites, and the interaction between neuronal cells and physiological factors.

Protection of Differentiating Neuronal Cells from Amyloid ß Peptide-induced Injury by Alkaline Extract of Leaves of Sasa senanensis Rehder.

BACKGROUND/AIM: We have previously reported the protection of doxorubicin-induced keratinocyte toxicity by alkaline extract of the leaves of Sasa senanensis Rehder (SE). In order to extend the generality of the cell protective effect of SE, we investigated whether it also protects rat PC12 and human SH-SY5Y neuron model cells from amyloid ß-peptide (Aß)-induced injury. MATERIALS AND METHODS: Viability of cells was determined by the MTT method. Cytotoxicity was evaluated by the concentration that reduces the cell viability by 50% (CC50). Protection from Aß-induced cytotoxicity was evaluated by the concentration that reversed the Aß-induced reduction of viability by 50% (EC50). The selectivity index (SI) of neuroprotective activity was defined as the ratio of EC50 to CC50 Aß1-42 aggregation was assayed using Aß1-42 ammonium hydroxide. RESULTS: SE showed hormetic growth stimulation at lower concentrations in both neuron precursors and differentiated cells. SE reproducibly inhibited Aß-induced cytotoxicity against both undifferentiated and differentiated neuron cells. Both the extent of differentiation induction and viability depended on the cell density, suggesting the release of growth and differentiation stimulation substances into culture supernatant. Higher concentrations of SE partially reduced the Aß1-42 aggregation. CONCLUSION: Hormetic growth stimulation and inhibition of aggregation may be involved in the neuroprotective activity of SE.