The effect of strain, growth stage, and cultivating condition of Ganoderma lucidum on 5α-reductase inhibition

The inhibitory effects of 102 methanol extracts of 40 mycelia, 9 culture fluids, and 53 fruiting bodies of 40 strains of Ganoderma lucidum on 5-reductase were investigated. The methanol extract of the fruiting body of each strain was found to show the strongest 5-reductase inhibitory activity among the extracts tested.     

Screening of extracts of Japanese woods for melanin biosynthesis inhibition

The effects of 120 methanol extracts prepared from bark and heartwood of 69 types of Japanese wood on the melanin production of B16 melanoma cells were examined. The melanin content of B16 melanoma cells was determined spectrophotometrically at 405nm. The extracts were also examined for their effects on cell viability. We found that the methanol extracts of Fagus crenata (buna, wood, 100μg/ml), Sapium sebiferum (Nankinhaze, wood, bark, 10μg/ml), and Zelkova serrata (keyaki, wood, 10μg/ml) greatly inhibited the melanin production of B16 melanoma cells without significant cytotoxicity. However, these extracts did not inhibit tyrosinase activity at the concentration of 100μg/ml. These findings indicate that the depigmenting mechanism of these extracts involves the suppression of some pigmenting signals in stimulating melanogenesis rather than the inhibition of tyrosinase activity. Part of this study was presented at the 53rd Annual Meeting of the Japan Wood Research Society, Fukuoka, Japan, March 2003     

Evaluation of biological activities of extracts from the fruiting body of <Emphasis Type="Italic">Pleurotus citrinopileatus</Emphasis> for skin cosmetics

Pleurotus citrinopileatus Singer has recently become a popular delicacy in East Asian countries. We prepared a methanol extract, soluble fractions from the methanol extract, and a hot water extract of the fruiting bodies of P. citrinopileatus. The biological activities such as melanin biosynthesis inhibition, tyrosinase inhibition, antioxidant activities [1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, oxygen radical absorbance capacity (ORAC), and superoxide dismutase (SOD)-like activity], antibacterial activities, and antihyaluronidase activities of these extracts were evaluated. We found that the n-hexanesoluble, diethyl ether-soluble, and ethyl acetate-soluble fractions exhibited melanin biosynthesis inhibition in B16 melanoma cells, as well as antioxidant (ORAC) and antibacterial activities. However, the n-butanol-soluble and water-soluble fractions and the methanol and hot water extracts exhibited antioxidant (DPPH radical scavenging, SOD-like activity) and antihyaluronidase activities. These results indicate that the fruiting bodies of P. citrinopileatus have the potential to be used as an ingredient in skin cosmetics.     

Rearing technique for proturans (Hexapoda: Protura)

A chamber for rearing proturans is described. The chamber is double-walled, and was used successfully to rear proturans for one generation.     

漆酶对木质素磺酸盐生物改性的研究

本研究由白腐菌液体培养基制得的粗漆酶改性麦麦草木质素磺酸盐。处理后木质素磺酸盐分子量分布明显向高分子量方向移动,木质素磺酸盐溶液的色度随之加深的同时,其分散性能得到明显氡改善,并且在此处理过程中漆酶具有很好的稳定性。     

Microbial communities in various waters used for fish larval rearing

A major concern in larvae production is a mass mortality caused by fish diseases. In larvae production, pumped‐up natural seawater filtered through a sand filter system is used for fish rearing, and microalgae and rotifer cultures. Here, we investigated the community structures of eukaryotic microbes, as well as total bacteria and vibrios, in various processed ‘waters’ used in a larvae production site. We observed that ultraviolet irradiation of seawater was effective to reduce not only total bacteria and vibrios but also eukaryotic microbes. Moreover, the community structures of total bacteria and vibrios in rearing waters for fish larvae were different from those in rotifer cultures fed with Chlorella, but rather similar to those in natural seawater and microalgae cultures. These results suggest that the bacterial community in rearing waters may originate mainly from natural seawater and then be selected by microalgae in rearing water. Overall, this study provides useful information for avoiding the risk of fish disease outbreaks in a larvae production site.     

YK-624产锰过氧化物酶的生产及初步纯化

利用白腐菌PhanerochaetesordidaYK 624(ATCC90872),采用Kirk液体培养基在富氧条件下进行振动培养,可得到锰过氧化物酶(MnP)活性较高和漆酶活性微量的酶液。该酶液通过超滤、透析、二乙氨基乙基琼脂糖凝胶(DEAE sepharoseCL 6B,pharmacia)离子交换柱层析的方法进行初步纯化后,得到比活性很高(1941.54IU/mg)的MnP酶液。漆酶活性和MnP活性比值的变化、SDS PAGE凝胶电泳试验和406nm附近的吸光值变化均表明,经离子交换柱层析后的YK1部分是主要的MnP,电泳试验同时表明纯化后的主要MnP的分子质量约为43kDa。经超滤、透析、离子交换柱层析纯化后得到的酶液YK1可用于进一步地研究及应用。     

5α-Reductase inhibitory compounds produced by polymerization of resveratrol with horseradish peroxidase

To produce 5-reductase inhibitory compounds, resveratrol was enzymatically oxidized in a horseradish peroxidase (HRP)/H₂O₂ system. Ethyl acetate extract of the oxidation products showed strong 5-reductase inhibitory activity with 10%–15% organic solvents in the system, whereas without organic solvent little inhibitory activity was exhibited. The optimum pH of enzymatic oxidation for acquisition of the inhibitory activity was 4.5. The inhibitory compounds were isolated and identified as resveratroltrans-dehydrodimer and resveratrolcis-dehydrodimer by comparing with published nuclear magnetic resonance data. The two resveratrol dehydrodimers have stronger inhibitory activity than natural resveratrol dimers and trimers found inShorea species.     

Screening of Indonesian plants for tyrosinase inhibitory activity

In our efforts to find new tyrosinase inhibitory materials, we investigated 44 Indonesian plants belonging to 24 families for tyrosinase inhibitory activity. The extracts of 5 Artocarpus woods showed potent tyrosinase inhibitory activity (over 80% at 100 μg/ml) similar to a positive control, kojic acid. In Artocarpus woods, the extracts of the sapwoods showed stronger inhibitory activity than those of the heartwoods. Chlorophorin was isolated as one of the active compounds in the sapwood of Artocarpus heterophyllus. The content of chlorophorin in sapwood was higher than that in heartwood. Part of this paper was presented at the 53rd (Fukuoka, March 2003) and 54th (Hokkaido, August 2004) Annual Meetings of the Japan Wood Research Society, and the 5th International Wood Science Symposium (Kyoto, September 2004)