The efficacy of the natural amendments in improving physical condition as well as waterretention characteristics of the growing media in pot culture was studied on seven different mixratio of growing media applied to soil. Growing media was prepared from peat, perlite, pruningwaste, pulp(3:1:3:3(w/w/w/w)). Growth substrates were prepared by mixing growing media at therates of 0%, 10%, 20%, 30%, 40%, 50% and 100% with soil at 100%, 90%, 80%, 70%, 60%,50% and 0%, respectively. The bulk density tended to decreased with increasing growing mediaproportions. The particle density was lowest(0.6 g/cm3) in sole growing media treatment and theporosity of all the soil mixed growing media(63.2~83.3%) was significantly higher than that ofthe soil as sole medium(60.7%). The water content was lowest in sole soil treatment(5.1%) andgrowing media as sole medium(57.8%) was the closely ideal range for pot culture(>60%). Although substrates were varying water to the atmosphere at similar rates which retained waterfor longer, growing media as sole still remain constant on high water content. It was confirmedthat strongly correlated between bulk density and water retentivity(correlation-0.85).

Insecticidal activity of active component isolated from Ruta chalepensis leaves was examined against maize weevil, Sitophilus zeamais and compared with two different bioassay system, such as direct contact and fumigant method. The methanol extract of R. chalepensis leaves had strongly (+++) insecticidal activity at 50 mg/disk against S. zeamais. Methanol extract of R. chalepensis was partitioned with hexane, chloroform, ethyl acetate, butanol and water fraction, successively. In this result, the highest activity was shown in chloroform fraction against S. zeamais. Biologically active compound derived from chloroform fraction of R. chalepensis extract was purified by using SiO2 column chromatography and prep-HPLC. The insecticidal constituent of R. chalepensis was identified as quinoline-4-carboxaldehyde by various chromatography and spectroscopic analysis methods. At 2.5 mg/disk, the most toxic activity against S. zeamais was exerted by the direct contact method (100%), followed by the fumigant method (23%). These results revealed that the contact toxicity showed 4.35 times greater than the respiration toxicity. Furthermore, these results indicate that quinoline- 4-carboxaldehyde could be useful as a new preventive agent against damage caused by stored-product insects.

The two-spotted spider mite, Tetranychus urticae Koch is the most harmful pest among many cropping systems, particularly vegetables and other annual crops. In this study, the methanol extract from the inner bark of Tabebuia impetiginosa was evaluated for acaricidal activity against T. urticae by using a leaf disk method and were compared with commercial acaricide, abamectin. A crude methanol extract of T. impetiginosa had strongly acaricidal activity at 2,000 ppm against the T. urticae. Methanol extract of T. impetiginosa was partitioned with hexane, chloroform, ethyl acetate, butanol and water fraction, successively. In this result, the chloroform fraction showed a strong acaricidal activity at 1,000 ppm. Therefore, active fraction of T. impetiginosa extract was purified by using silica gel column chromatography and high performance liquid chromatography. The structure of acaricidal component was analyzed by EI-MS, 1H-NMR and 13C-NMR spectra, and was identified as TI-3123. Based on the LC50 values of TI-3123 and abamectin against T. urticae were resulted in 0.011 mg/l and 0.340 mg/l, respectively. These results showed that acaricidal activity of the T. impetiginosa can be mostly attributed to TI-3123. Furthermore, TI-3123 was approximately 30.91 times more toxic than abamectin against T. urticae. All these results suggested that active component in T. impetiginosa derived materials could be use for biological control for T. urticae. Further studies should be performed to the structure activity relationship of TI-3123 and compared with its derivatives.

The effects of chitosan upon the experimentally induced differentiation of MDPC-23 cells, derived from mouse dental papilla cells, were investigated by RT-PCR, observations of cell morphology and Alizaline red-S staining. Chitosan was found to significantly increase and accelerate the expression of ALP mRNA but decrease the ColI transcript levels, as compared with the control, in a time-dependent manner during the differentiation of MDPC-23 cells. Chitosan also significantly downregulated ON mRNA expression and accelerated mineralization in differentiating MDPC-23 cells. These results suggest that chitosan facilitates odontoblast differentiation and mineralization and may have potential clinical applications as a dentin regeneration material.

The protective effect of ethanol extract of Korean mistletoe (KM; Viscum album coloratum) on hydrogen peroxide (H2O2)-induced neurotoxicity was examined in primary cultured rat cortical neurons. H2O2 reduced viability of cortical neurons in a concentration-dependent manner. The addition of KM, over a concentration range of 10 to 100 μg/ml, concentration-dependently prevented the H2O2(100 μM)-induced neuronal cell death, as assessed by a 3-[4,5-dimethylthiazol-2-yl]-2,5-di-phenyl-tetrazolium bromide (MTT) assay and Hoechst 33342 staining. KM significantly inhibited H2O2-induced elevation of the cytosolic Ca2+ concentration ([Ca2+]c), which was measured by a fluorescent dye, fluo-4 AM. KM inhibited glutamate release into medium and generation of reactive oxygen species (ROS) induced by H2O2. These results suggest that KM may mitigate the H2O2-induced neurotoxiciy by interfering with the increase of [Ca2+]c, and inhibiting glutamate release and generation of ROS in cultured neurons.

Paeoniae radix has been widely used for its anti-allergic, anti-inflammatory and analgesic effects, and demonstrated to have anticonvulsant, memory enhancing and anxiolytic activities. The present study was performed to examine the protective effect of methanol extract of Paeoniae radix (PR) from Paeoniae Japonica Miyabe et Takeda (Paeoniaceae) on hydrogen peroxide (H2O2)-induced neurotoxicity using cultured rat cerebral cortical neuron. H2O2 produced a concentration-dependent reduction of neuronal viability, PR, over a concentration range of 10 to 100 μg/ml showed concentration-dependent decrease of the H2O2(100 μM)-induced neuronal cell death, as assessed by a 3-[4,5-dimethylthiazol-2-yl]-2,5-di-phenyl-tetrazolium bromide assay and the number of apoptotic nuclei, evidenced by Hoechst 33342 staining. PR (100 μg/ml inhibited 100 μM H2O2-induced elevation of the cytosolic Ca2+ concentration ([Ca2+]c), which was measured by a fluorescent dye, flue-4 AM. PR (50 μg/ml inhibited glutamate release into medium induced by 100 μM H2O2, which was measured by HPLC, and generation of reactive oxygen species (ROS). These results suggest that PR may mitigate the H2O2-induced neurotoxiciy by interfering with the increase of [Ca2+]c, and then inhibiting glutamate release and generation of ROS in cultured neurons.