Scopolefin exhibited an immediate and dose-dependent hypour-icemic effect after intraperitoneal administration (50, 100, 200mg/kg) in hyperuricemic mice induced by potassium oxo-nate; however, it did not affect the serum uric acid level in nor-mal mice at the tested doses. For exploring the involved mecha-nisms of action of scopoletin, potential inhibitory effects on xan-thine oxidase and possible uricosuric effects were investigated.Scopolefin (50, 100, 200mg/kg) significantly inhibited the activ-ity of xanthine oxidase in liver homogenates of hyperuricemicmice although it only showed a relatively weak, albeit competi-tive-type, inhibition of xanthine oxidase in a commercial assay.Furthermore, a potent uricosuric effect of scopoletin (100, 200mg/kg) was ascertained. These results demonstrated for thefirst time that scopoletin exhibits, hypouricemic activitiesthrough decreasing uric acid production and as well as a uricosu-tic mechanism.

Aim A regional model of vegetation dynamics was enhancedto include biogeochemical cycling of nitrogen and was thenapplied to a forest transect in east China (FTEC) in order to investigatethe responses of the transect to possible global change. Location Eastern China. Methods Biomass and nitrogen concentration of green andnongreen portions of vegetation, moisture contents of threesoil layers, and total and available soil nitrogen are includedas state variables in the enhanced model. The model wasparameterized and validated against field observations ofbiomass, productivity, plant and soil nitrogen concentration,nitrogen uptake, a vegetation index derived from satelliteremote sensing and digital maps of vegetation and soil distributionsalong a forest transect in eastern China (FTEC). The model was applied to FTEC in order to investigate theresponsive characteristics of the ecosystems to global climaticchange. Scenarios of climate change under doubled CO2produced by seven general circulation models (GCM) wereused to drive the model. Results The simulations indicated that the model is capableof simulating accurately potential vegetation distribution andnet primary productivity under contemporary climatic conditions.The simulations for GCM-projected future climatescenarios with doubled atmospheric CO2 concentrationpredicted that broadleaf forests would increase, but coniferforests, shrubs and grasses would decrease; and that deciduousforests would have the largest relative increase, but evergreenshrubs would have the largest decrease. Conclusions The overall effects of doubling CO2 and climaticchanges on FTEC were to produce an increased net primaryproductivity (NPP) at equilibrium for all seven GCM scenarios.The inclusion of nitrogen dynamics in the model imposesmore constraint on the responses of FTEC to climatic changethan the previous version of the model without nitrogendynamics. Temperature exerts a stronger control on NPPthan precipitation, as indicated by the negative correlationsbetween NPP and temperature. The southern portion of FTEC,at latitudes less than 33

目的：观察熟地（黄）和生地（黄）配伍的四物汤对实验性变态反应的影响，比较其作用差异。方法：以compound48/80诱导小鼠过敏性休克、皮肤搔抓反应及大鼠腹腔肥大细胞释放组胺，分别测定1h内的死亡率、10min内的搔抓次数及组胺的释放量和残留量（荧光法）；以氯化钴诱导小鼠耳廓迟发型超敏反应，测定耳廓肿胀度。结果：熟地配伍的四物汤（500mg/kg）显著抑制compound48/80所致小鼠过敏性休克，而生地配伍的四物汤无明显影响；熟地和生地配伍的四物汤（500mg/kg）均明显抑制compound48/80诱导的小鼠搔抓反应及氯化钴所致小鼠迟发型超敏反应，前者的作用强于后者；体外试验中，熟地或生地配伍的四物汤（100～400μg/ml）抑制compound48/80诱导的大鼠肥大细胞释放组胺，前者的作用强于后者，熟地提取物减少组胺释放，而生地提取物无明显作用。结论：熟地配伍的四物汤对肥大细胞依赖性速发型变态反应及T淋巴细胞依赖性迟发型变态反应的抑制作用均强于生地配伍的四物汤，熟地和生地作用的差异可能是其主要原因。

The anti-allergic effects of a 70% ethanol extract from Selaginella tamariscina herb (EST) were evaluated in this study. EST given at the doses of 500 and 1000mg/kg can inhibitmouse systemic anaphylactic shock induced by compound 48/80 in a dose-dependent manner.It can also dose-dependently block rat homologous passive cutaneous anaphylaxis and skinreactions caused by exogenous histamine and serotonin with a significant difference observedat the dose of 1000mg/kg. In addition, EST can reduce histamine release from rat peritonealmast cells triggered by compound 48/80 and an antigen in vitro. When incubated with ratmast cells, the extract (200μg/ml) can significantly elevate the intracellular cAMP levels.The finding suggests that EST inhibits mast cell-dependent, immediate allergic reactions. Itseffects appear to be mediated by reducing the release of vasoactive amines such as histaminefrom mast cells via stabilizing the cell membrane and weakening the inflammatory action ofthese amines. Based on these results, Selaginella tamariscina and one of its active componentsflavonoids may be useful as potential remedies for allergic rhinitis and other allergy-relateddiseases.

Previous studies have shown that the ethanol extract ofPlumbago zeylanica L. stems (EPZ) suppresses immediateallergic reactions. We extended these studies to examinethe effect of EPZ on delayed-type hypersensitivity reactions. Our results showed that EPZ (500 and 1000mg=kg), orally administered during either sensitizationstage or effector stage, effectively attenuated picryl chloride–induced delayed-type hypersensitivity (PC-DTH) inmice. In vitro, EPZ (100 and 200mg=ml) concentrationdependentlyinhibited Con A-induced splenocyte proliferationand interleukin-2 (IL-2) production but hadlittle effect on nitric oxide (NO) production from murineperitoneal macrophages activated with lipopolysaccharide(LPS). EPZ (500 and 1000mg=kg) also showed asignificant inhibition of ear swelling caused by xylene inmice. These results suggested that EPE alleviateddelayed-type hypersensitivity in mice, which might beattributable to inhibition of proliferation and differentiationof T lymphocytes as well as anti-inflammatoryactivities.