乌梅抑制黑色素的机制

目的研究乌梅酸性成分提取物抑制黑色素产生的机制。方法用免疫组分化学法和化学比色法观察乌梅对黄褐斑模型豚鼠皮肤黑素细胞病理形态学和一氧化氮合酶(NOS)活性的影响。结果①乌梅酸性成分提取物在高(25 mg/mL)、中(12.5 mg/mL)、低(6.25 mg/mL)浓度时,豚鼠皮肤平均光密度、积分光密度、黑素细胞阳性率明显低于模型组和溶媒对照组(P<0.05),平均灰密度高于模型组、溶媒对照组(P<0.05);中浓度组与阳性药物组相比,平均光密度、平均灰密度、黑素细胞阳性率均有显著差异(P<0.05);②乌梅提取物3个浓度组的豚鼠皮肤黑素细胞NOS表达明显减少,与模型组相比有显著差异(P<0.05)。结论乌梅影响黑色素合成的机制与降低紫外线促黑素生成,调控黑素细胞的NOS表达,阻断NO黑素信号传导有关。

Effects of Different Irrigation Modes on Internal Quality of Flue-cured Tobacco Leaves

[Objective] This study aimed to investigate the effects of different irrigation modes on chemical constituent and aroma substance contents and sensory quality in flue-cured tobacco leaves. [Method] Field experiments were conduced with two treatments, including watering irrigation and micro-spraying irrigation. In watering irrigation treatment, flue-cured tobacco seedlings were respectively watered by artificial root irrigation once at rosette stage（May 26） and vigorous growth stage（June 18）, 1kg/plant each time; in micro-spraying treatment, flue-cured tobacco seedlings were watered by artificial root irrigation once at rosette stage（May 26）, 1 L/plant. [Result]Compared to watering irrigation mode, micro-spraying irrigation could extremely significantly increase the content of main aromatic substance in middle and upper leaves.Contents of main aromatic substance non-volatile organic acids, volatile organic acids, petroleum ether extracts, neophytadiene and neutral aromatic substances in C3F tobacco leaves were improved by 24.4%, 32.6%, 20.7%, 33.8% and 26.3%, respectively; contents of main aromatic substance non-volatile organic acids, volatile organic acids, petroleum ether extracts, eophytadiene and neutral aromatic substances in B2F tobacco leaves were improved by 16.3%, 6.0%, 6.1%, 10.8% and8.1%, respectively. In addition, micro-spraying irrigation could extremely significantly reduce the nicotine content in middle and upper leaves and improve the aromatic coordination, mellow taste and smoldering property. [Conclusion] In flue-cured tobacco production, micro-spraying technology is an important means to improve the internal quality of flue-cured tobacco leaves, which can be adopted to effectively solve the problem of declining quality of flue-cured tobacco leaves resulted from the dry climate at maturation stage in seasonal frequent-drought areas.

Antioxidant Activity of Isothiocyanate Extracts from Broccoli

Isothiocyanates(ITCs) extracts were prepared from fresh broccoli.Their antioxidant properties were evaluated by using the in vitro bioassays,including superoxide anion radical( 2 O·-) ,hydroxyl radical(HO·-) and 2,2-diphenyl-1-picrylhydracyl(DPPH·) radical-scavenging methods,lipid peroxidation assay,and reducing power assay.The ITCs extracts exhibited significant dose-dependent antioxidant activities(P<0.01) .Its antioxidant-stability was affected by temperature and storage condition,although it was more stable than vitamin C(Vc) .GC-MS iden-tified sulforaphane in the ITCs extracts.The antioxidant activity of sulforaphane was approximately one tenth to one fifth of that of Vc.Sulforaphane was experimented to be one of dominating contributors to antioxidant capacity of ITCs extracts.However,there was no direct antioxidant activity found for benzyl isothiocyanate(BITC) in vitro. Therefore,it could be concluded that the general group(-N=C=S) was not the essential part for the antioxidant activity of sulforaphane.It is suggested that the ITCs extracts from broccoli can be developed into a promising food additive for healthy food.

Chemical constituents of marine mangrove-derived endophytic fungus Alternaria tenuissima EN-192

A chemical investigation of the ethyl acetate extract of the fermentation broth of Alternaria tenuissima EN- 192, an endophytic fungus obtained from the stems of the marine mangrove plant Rhizophora stylosa, resulted in the isolation of nine known secondary metabolites, including four indole-diterpenoids： penijanthine A （1）, paspaline （2）, paspalinine （3）, and penitrem A （4）; three tricycloalternarene derivatives： tricycloalternarene 3a （5）, tricycloalternarene lb （6）, and tricycloalternarene 2b （7）; and two alternariol congeners： djalonensone （8） and alternariol （9）. The chemical structures of these metabolites were characterized through a combination of detailed spectroscopic analyses and their comparison with reports from the literature. The inhibitory activities of each isolated compound against four bacteria were evaluated and compounds 5 and 8 displayed moderate activity against the aquaculture pathogenic bacterium Vibrio anguillarum, with inhibition zone diameters of 8 and 9 mm, respectively, at 100 gg/disk. To the best of our knowledge, this is the first report on the secondary metabolites of mangrove-derived Alternaria tenuissima and also the first report of the isolation ofindole-diterpenoids from fungal genus Alternaria.

Antibacterial Activity of Extracts from Zostera marina Against Pathogens of Apostichopus japonicus Skin Ulceration Disease

The purpose of this study was to investigate the antibacterial activity of extracts from Zostera marina against the pathogens of Apostichopus japonicus skin ulceration disease.When 95% ethanol (v/v) solvent was used to extract Zostera marina at 50℃,aqueous extract (ZA) showed obvious bacteriostatic effects on the tested bacterial strains (inhibition halo diameters between 8.23 mm and 13.62 mm),whereas the ethyl acetate extract (ZE) was almost inactive.The minimal inhibitory concentration (MIC) of ZA against four pathogens were homogeneous at 12.8 g L-1.ZA components were analyzed by thin layer chromatography (TLC) assay and six fractions were obtained.In another study,the six fractions showed inhibitory effects against the tested bacteria while their functions seemed to counteract the ZA activity.

Screening and isolation of the algicidal compounds from marine green alga Ulva intestinalis

Twenty species of seaweed were collected from the coast of Zhejiang, China, extracted with ethanol, and screened for algicidal activity against red tide microalgae H eterosigma akashiwo and Prorocentrum micans. Inhibitory eff ects of fresh and dried tissues of green alga U lva intestinalis were assessed and the main algicidal compounds were isolated, purifi ed, and identifi ed. Five seaweed species, U. intestinalis, U. fasciata, Grateloupia romosissima, Chondria crassicaulis, and Gracilariopsis lemaneiformis, were investigated for their algicidal activities. Fresh tissues of 8.0 and 16.0 mg/m L of U. intestinalis dissolved in media signifi cantly inhibited growth of H. akashiwo and P. micans, respectively. Dried tissue and ethyl acetate(Et OAc) extracts of U. intestinalis at greater than 1.2 and 0.04 mg/m L, respectively, were fatal to H. akashiwo, while its water and Et OAc extracts in excess of 0.96 and 0.32 mg/m L, respectively, were lethal to P. micans. Three algicidal compounds in the Et OAc extracts were identifi ed as 15-ethoxy-(6z,9z,12z)-hexadecatrienoic acid(I),(6E,9E,12E)-(2-acetoxy- β- D-glucose)-octadecatrienoic acid ester(II) and hexadecanoic acid(III). Of these, compound II displayed the most potent algicidal activity with IC_(50) values of 4.9 and 14.1 μg/m L for H. akashiwo and P. micans, respectively. Compound I showed moderate algicidal activity with IC_(50) values of 13.4 and 24.7 μg/m L for H. akashiwo and P. micans, respectively. These fi ndings suggested that certain macroalgae or products therefrom could be used as ef fective biological control agents against red tide algae.

几种习用代茶植物体外降糖活性研究

研究藤茶、石崖茶、多穗石柯茶、大叶苦丁茶、小叶苦丁茶、青城山苦丁茶、广西甜茶、老鹰茶、金银花茶、青钱柳茶的体外降糖活性。通过测定其水提物中总黄酮、总多酚含量,以及对各部分的α-葡萄糖苷酶抑制率及DPPH自由基清除率进行比较研究。结果表明:在酸性提取物方面,提取率最高为藤茶((35.76±2.18)%),总黄酮和总多酚含量最高的分别是藤茶((7.83±0.76)%)和大叶苦丁茶((8.31±0.43)%)。10种代茶植物水提物的酸性部位α-葡萄糖苷酶抑制活性较好的为石崖茶(IC50=(0.004±0.001)mg/mL)、老鹰茶(IC50=(0.014±0.001)mg/mL)、藤茶(IC50=(0.022±0.001)mg/mL);DPPH自由基清除活性较好的也为老鹰茶(IC50=(0.009±0.004)mg/mL)、藤茶(IC50=(0.015±0.001)mg/mL)、石崖茶(IC50=(0.015±0.001)mg/mL)。藤茶、石崖茶和老鹰茶体外降糖活性相对较好,可考虑用于糖尿病患者的辅助治疗。

Acid volatile sulfide and simultaneously extracted metals in superficial sediments from Baihua Lake, China

The bioavailability of five divalent cationic heavy metals （Pb, Cd, Cu, Zn and Ni） in 10 superficial sediment samples from Baihua Lake was assessed based on the molar ratio of simultaneously extracted metals （SEMs） to acid volatile sulfide （AVS）. Atomic absorption spectrometry （AAS） and X-ray powder diffraction （XRD） were used to determine the heavy metal concentrations and examine the mineralogy of the crystalline phases, respectively. The AVS loadings in sediments from Baihua Lake ranged from 64.30 to 350.08 ~rnol/g （dry weight）. The corresponding SEM levels for the sampling sites varied from 1.770 to 14.660 vrnol/g. The molar ratio of SEMs to AVS ranged from 0.014 to 0.084 with a mean value of 0.034. The XRD analysis also confirmed the presence of some metal sulfides in sediments from Baihua Lake. The SEMs/AVS ratios for all sampling sites were significantly lower than 1.0, indicating that AVS in the sediments was sufficient to bind the five heavy metals; thus, these heavy metals are currently not significantly bioavailable to benthic organisms. Comparing the SEMs results to published guideline values for metal toxicity to benthic organisms in sediments, however, suggests that Zn and Ni pose a risk at some sampling locations in Baihua Lake.

The Potency of Sargassum dupficatum Bory Extract on Inflammatory Bowel Disease Therapy in Rattus norvegicus

Inflammatory Bowel Disease （IBD） was a chronic inflammatory disease of the digestive tract especially in small and large intestines that induced by indomethacin. Potency of ethanol and ethyl acetate extract from brown seaweed （Sargassum duplicatum Bory） against indomethacin induced jejunum damage was evaluated in Rattus norvegicus. Control rats induced by corn oil orally. IBD rats induced by indomethacin of 15 mg/kg body weight （bw） orally and incubated for 7 days. Therapy rats were treated orally by brown seaweed extract of 100 mg/kg bw respectively for seven days. Based on phytochemistry test, Sargassum duplicatum Bory extract contains flavonoids, phlorotanin, and alkaloid. The result of preparative Thin Layer Chromatography （TLC） and Infra Red （IR） spectrum of extract spots showed the same result （function group similarity） with gallic acid standard as polyphenol. Sargassum duplicatum Bory extract decreased Malondialdehid （MDA） level （54.20%） significantly using Thiobarbituric Acid （TBA） assay, repaired ZO-1 and occludin protein expressions by immunohistochemistry and repaired jejunum damage by histological observation.

Tests of Antibiotic Properties of Algerian Desert Truffle against Bacteria and Fungi

In the present paper, the ethyl acetate extract from the fruiting bodies of Tirmania pinoyi （Maire） was obtained by Soxhlet extraction. Six fractions were separated from this extract using two chromatographic methods. All these fractions were submitted to antimicrobial activity against four clinically important bacteria Staphylococcus aureus ATCC6538, Enterococcusfaecalis ATCC6538 Pseudomonas aeruginosa ATCC14028, Escherichia coli ATCC25922 and one pathogenic fungus Candida albicans ATCCI0231. The in vitro antimicrobial activity was performed by agar disc diffusion method. The fractions with the greatest antimicrobial activity were fractions 02 and 06 which inhibited growth of both Gram negative and Gram positive bacteria and had significant antifungal activity against Candida albicans. The present study validates the folk use of the boiled truffle water-extract and indicates that it could be effective potential candidates for the development of new strategies to treat bacterial or fungal infections.