Chemical Constituents of the Bulbs of Scilla peruviana and Their Pancreatic Lipase Inhibitory Activity.

Scilla species are used as medicinal plants and contain lanosterol-type triterpene glycosides. The phytochemical investigation of the bulbs of Scilla peruviana led to the isolation of 17 compounds, including three new rearranged pentacyclic-lanosterol glycosides (1-3) and two new homoisoflavanone glycosides (12 and 13). The structures of the undescribed compounds were determined by extensive spectroscopic analyses, including two-dimensional (2D) NMR. Among the triterpene glycosides, 2, 3, and 6 showed significant pancreatic lipase inhibitory activity in a concentration-dependent manner in vitro. The oral administration of scillascilloside D-2 (6) reduced serum triglyceride levels in a dose-dependent manner in soybean oil-loaded mice.

Change in Anticancer Drug Sensitivity During Neuronal Differentiation of PC12 Cells.

BACKGROUND/AIM: Although there are many reports of anticancer drug-induced neurotoxicity, most previous data have been derived from neuronal cell models grown in a variety of culture conditions. This has prevented accurate assessment of the potency of their neurotoxicity and of changes in drug sensitivity of neuronal cells during differentiation. In this study, a simple neuronal differentiation induction system was established and the relative potency of neurotoxicity of eight anticancer drugs was compared during neuronal cell differentiation. MATERIALS AND METHODS: Rat PC12 cells were induced to differentiate into neuronal cells by 50 ng/ml nerve growth factor in serum-free Dulbecco's modified Eagle's medium, followed by overlay of fresh nutrients at day 3, without medium change. Cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. RESULTS: During differentiation, PC12 cells became 1.1-to more than 10,000-fold resistant to anticancer drugs. Topoisomerase inhibitors (doxorubicin, SN-38, etoposide) were the most toxic to differentiated PC12 cells, followed by docetaxel, gefitinib, melphalan, 5-fluorouracil and methotrexate. Docetaxel showed the highest cytotoxicity against undifferentiated PC12 cells, but its cytotoxicity was dramatically reduced during differentiation. CONCLUSION: The present study demonstrated considerable variation in the neurotoxicity of anticancer drugs during the cell differentiation process. The present simple assay system may be useful to search for neuroprotective substances.

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.

Structural analysis of neutral glycosphingolipids from the silkworm Bombyx mori and the difference in ceramide composition between larvae and pupae.

Glycosphingolipids (GSLs) from the silkworm Bombyx mori were identified and GSL expression patterns between larvae and pupae were compared. The structural analysis of neutral GSLs from dried pupae revealed the following predominant species: Glcß1Cer, Manß4Glcß1Cer, GlcNAcß3Manß4Glcß1Cer, Galß3Manß4Glcß1Cer, GalNAcα4Galß3Manß4Glcß1Cer, GlcNAcß3Galß3Manß4Glcß1Cer, Galα4Galß3Manß4Glcß1Cer and (GalNAcα4)1-4 GalNAcα4Galß3Manß4Glcß1Cer. Lin-ear elongation of α4-GalNAc was observed at the non-reducing end of Galß3Manß4Glcß1Cer with up to five GalNAc repeats. The arthro-series GSL GlcNAcß3Manß4Glcß1Cer, a characteristic GSL-glycan sequence of other Arthropoda, was detected in silkworms. The main ceramide species in each purified GSL fraction were h20:0-d14:1 and h22:0-d14:1. GSL expression patterns in larvae and pupae were compared using thin-layer chromatography, which demonstrated differences among acidic, polar and neutral GSL fractions, while the zwitterionic fraction showed no difference. Neutral GSLs such as ceramides di-, tri- and tetrasaccharides in larvae showed less abundant than those in pupae. MALDI-TOF MS analysis revealed that larval GSLs contained four types of ceramide species, whereas pupal GSLs contained only two types. The structural analysis of neutral GSLs from silkworms revealed a novel series of GSLs. The comparison of GSL expression patterns between larvae and pupae demonstrated differences in several fractions. Alterations in GSL ceramide composition between larvae and pupae were observed by MALDI-TOF MS analysis.

Re-evaluation of Culture Condition of PC12 and SH-SY5Y Cells Based on Growth Rate and Amino Acid Consumption.

BACKGROUND/AIM: Most of the previous investigators have used various types of media for the culture of nerve cells. In order to optimize the culture conditions, we compared the growth rate and amino acid consumption by two popular neuron models, rat PC12 and human SH-SY5Y, grown in DMEM or DMEM: Ham's F-12 (1:1): non-essential amino acids, supplemented with 10% fetal bovine serum (referred to DMEM and Mix, respectively). MATERIALS AND METHODS: Cell growth was monitored by the MTT method. Amino acids in the culture medium were quantitated by amino acid analysis after deproteinization. RESULTS: Efficient cell attachment could be achieved even if PC12 cells were inoculated at extreme lower cell density in a non-coated plain dish, without addition of its condition medium. Both PC12 and SH-SY5Y cells proliferated up to slightly higher cell density in DMEM than in Mix. Approximately 2-fold higher utilization rate of glutamine and essential amino acids was observed in DMEM. Amyloid peptides such as Aß1-42 and Aß25-35 suppressed their growth nearly by 50%. CONCLUSION: The present study suggests the usefulness of DMEM for the study of searching neuroprotective substances, based on its favorable effects on cell attachment, cell growth and amino acid utilization as well as amyloid peptide sensitivity.