核桃内生真菌对几种致病菌的拮抗试验研究

用25种核桃内生真菌,分别与玉米小斑、小麦赤霉、番茄灰霉病原菌进行两点对峙培养拮抗实验,结果表明：23种核桃内生菌抑菌活性对玉米小斑病病原菌极强者5属,对小麦赤霉病病原菌极强者i属,对番茄灰霉病病原菌没有极强者。小卵孢霉对玉米小斑病、小麦赤霉病和蕃茄灰霉病病原菌的抑菌活性都极强,可以初步作为防治这3种作物病害的生物源农药首选菌种;单孢枝霉对该3种病原菌的抑菌活性强。壳大卵孢霉对小麦赤霉病和蕃茄灰霉病病病原菌,粘盘孢属对玉米小斑病和蕃茄灰霉病病原菌抑菌活性强,单孢枝霉、壳大卵孢霉和粘盘孢属也可以作为防治这3种作物病原菌的优选菌株。     

苦楝提取物的提取及其抑菌活性的研究

对苦楝提取物的提取及提取物对真菌的抑菌活性进行了研究。考察了提取剂种类、提取温度、提取时间、提取次数、料液比等因素对苦楝素提取的影响。结果表明：苦楝素优选提取条件为：以60％乙醇为提取剂，料液比1：9，在60℃条件下提取4次、每次80min，苦楝素的得率为1．08％。用苦楝树皮和果实的不同溶剂的提取物对两种真菌(黑曲霉、绿色木霉)进行抑菌试验，结果发现苦楝树皮和果实不同浓度的提取物的抑菌活性有很大区别；不同溶剂提取物的抑菌活性也不同。从整体看苦楝树皮提取物对供试菌的抑制效果比苦楝果实好。苦楝树皮乙醇提取物对两种供试菌的生物活性最强，对绿色木霉和黑曲霉有很好的抑菌活性。最低抑菌浓度的试验表明：苦楝树皮乙醇提取液对绿色木霉和黑曲霉的最低抑菌浓度均为0．5％，其中甲醇提取物对绿色木霉和黑曲霉的最低抑菌浓度为2％。     

异樟叶精油的抑菌活性及其化学成分

运用水蒸汽蒸馏法提取异樟叶精油,采用平板抑菌法检测精油对真菌的抑菌活性,并利用气-质(GC/MS)联用技术分析精油的化学成分.结果表明:异樟叶精油对尖孢镰刀菌、七叶树壳梭孢和拟茎点霉均具有抑制效果,抑菌率分别达到42.64％,57.50％和64.30％,对拟茎点霉的抑制效果最好;从异樟叶精油中鉴定出41种物质,包括烯烃类物质20种,酮类物质1种,酯类物质3种,醚类物质3种,氧化物类物质1种和醇类物质13种.     

木霉对苗木土传病原真菌的拮抗作用

体外测定表明，木霉菌株Ｔ—１６９和Ｔ—２７９对病原菌Ｒｈｉｚｏｃｔｏｎｉａｓｏｃｌａｎｉ（立枯丝核菌）、Ｆｕｓａｒｉｕｍｏｘｙｓｐｏｒｕｍ（尖孢镰刀菌）、Ｐｙｔｈｉｕｍａｐｈａｍｉｄｅｒｍａｔｕｍ（腐霉）和Ａｌｔｅｒｎａｒｉａｔｅｎｕｉｓ（交链孢霉）在对峙培养中的拮抗系数分别为２、２～３和３。温室测定表明，用０．６％（Ｗ／Ｗ）Ｔ－１６９麸皮培养物（１０７ｃｆｕ／ｇ）处理土壤。在人工接种立枯丝核菌、尖孢镰刀菌、腐霉及交链孢霉２０ｄ后，落叶松苗木发病率分别比未用木霉处理的对照减少４９．６％、１７．４％、１８．３％和１１．７％；用Ｔ－１６９和Ｔ－２７９木霉孢子悬浮液（１０８ｃｆｕ／ｍｌ）处理落叶松种子，人工接种立枯丝核菌１９ｄ后，落叶松成苗率分别比未用木霉处理的对照增加１８．８％和１２．７％。     

3种植物粗提物对6种植物病原菌抑菌活性研究

试验研究了平枝栒子(Cotoneaster horizontalis)、苍耳(Xanthium sibiricum)、花椒(Zanthoxylum bungeanum)3种植物粗提物对玉米弯孢菌(Curvularia lunata)、向日葵菌核(Sclerotinia sclerotiorum)、人参灰霉(Botrytis cinerea)、人参黑斑(Alternaria panax)、瓜果腐霉(Pythium aphanidermatum)、辣椒疫霉(Phytophthora capsici)6种植物病原菌的抑菌活性。结果表明:平枝栒子和苍耳粗提物对6种病原菌均有较好抑菌效果,其中平枝栒子和苍耳对人参灰霉菌抑菌活性较明显,抑菌率分别为89.87%和83.54%。花椒除对人参灰霉有一定的抑菌效果外,对其它5种病原菌均存在一定程度上的促生长作用。     

纤维降解高温微生物的产酶特性研究

对分离的一株高温好氧微生物曲霉与嗜热侧孢霉及木霉的产酶特性进行了比较。利用固体培养方法，研究了该株曲霉与嗜热侧孢霉和木霉的产纤维素酶、木聚糖酶和CMC酶的活性。结果表明，实验条件下，所用菌株中嗜热侧孢霉具有最高的木聚糖酶活性（164．4U／g），木霉具有最高的纤维素酶活性和CMC酶活性（分别为12．1和77．2U／g），同时曲霉和嗜热侧孢霉也具有较高的纤维素酶活性和CMC酶活性，所用曲霉和嗜热侧孢霉一样，适合作纤维降解的微生物。     

芽枝状枝孢霉和蜡蚧轮枝菌防治湿地松粉蚧研究初报

用芽枝状枝孢霉ＣｌａｄｏＳｐｏｒｉｕｍｃｌａｄｏｓｐｏｒｉｄｅｓ（Ｆｒｅｓ．）Ｄｅｒｒｕｅｓ和蜡蚧轮枝菌Ｖｅｒｔｉｃｉｌｌｉｕｍｌｅｃａｎｉｉ的孢子液２．５×１０７／ｍｌ和１．７Ｘｌ０７／ｍｌ防治湿地松粉蚧Ｏｒａｃｅｌｌａａｃｕｌａ（Ｌｏｂｄｅｌｌ），试验结果为：在室内，用芽枝状枝孢霉的校正死亡率分别为８２．７％和８５．ｏ％，用蜡蚧轮枝菌的校正死亡率分别为８６．７％和６５．９％；林地每公顷喷孢量为３３×１０１２和１６．５×１０１２个孢子防治湿地松粉蚧，用芽枝状枝孢霉的校正死亡率分别为４５．２％和８１．０％，用蜡蚧轮枝菌的校正死亡率分别为９２．７％和９９．５％。初步认为上述两种菌在湿地松粉蚧防治上具有应用前途。     

10种杀菌剂对大叶黄杨坏损尾孢菌的毒力测定

采用室内生长速率法和载玻片上萌发法测定了50％多菌灵超微WP等10种供试杀菌剂对坏损尾孢菌Cercospora destructive Ravo菌落和孢子的抑菌作用。结果表明：70％甲基硫菌灵WP、30％氟菌唑WP、50％多菌灵超微WP和15％三唑酮WP等4种药剂对坏损尾孢菌菌落具有极强的毒力,70％甲基硫菌灵WP、50％腐霉利WP、30％氟菌唑WP和50％多菌灵超微WP对坏损尾孢菌孢子萌发抑制率极高。     

高节竹梢枯病发生规律及防治试验

在掌握高节竹梢枯病Arenrinium phaeospermurn发生规律的基础上，对10种杀菌剂进行室内药效测定，选出的70％甲基托布津、50％多菌灵、80％402乳剂、40％异稻瘟净、20％粉锈宁等5种杀菌剂对暗孢节菱孢菌有较强的抑菌作用。野外防治试验表明，采用综合治理措施，防治效果可达88．2％。     

芽枝状枝孢霉和螨蚧轮枝菌防治湿地松粉蚧研究初报

用芽枝状枝孢霉Ｃｌａｄｏｓｐｏｒｉｕｍ ｃｌａｄｏｓｐｏｒｉｏｉｄｅｓ（Ｆｒｅｓ）Ｄｅｒｒｕｅｓ和蜡蚧轮枝菌Ｖｅｒｔｉｃｉｌｌｉｕｍ ｌｅｃａｎｉｉ的孢子液２．５×１０＾７０／ｍｌ和０１．７×１０＾７／ｍｌ防治湿地松粉蚧Ｏｒａｃｅｌｌａａｃｕｌａ（Ｌｏｂｄｅｌｌ），试验结果为：在室内，用芽枝状枝孢霉的校正死亡率分别为８２．７％和８５．０％，用蜡蚧轮板菌的校正死亡率分别为８６．７％和６５．９％；林地     

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.     

莰烯醛肟及其烃基醚衍生物的合成与抑菌活性研究

由莰烯醛(1)与羟胺盐酸盐反应合成了莰烯醛肟(2),继而与卤代烃反应合成了5种莰烯醛肟烃基醚衍生物,分别为:莰烯醛肟乙基醚(3a)、莰烯醛肟正丙基醚(3b)、莰烯醛肟正丁基醚(3c)、莰烯醛肟正戊基醚(3d)和莰烯醛肟苄基醚(3e)。通过红外光谱、质谱和核磁共振等仪器分析手段对产物结构进行了确认。在此基础上,采用菌丝生长速率法,评价了莰烯醛肟及其烃基醚衍生物对12种植物病原真菌的生长抑制作用,结果表明:产物对12种植物病原真菌皆有一定抑制作用,其中莰烯醛肟的抑菌活性最优,并且对油茶炭疽病的抑制效果最好,EC 50为39.25 mg/L,对水稻纹枯病菌、猕猴桃果实拟茎点霉、玉米赤霉病菌和毛竹枯梢病病原菌的EC 50为40~50 mg/L;在质量浓度为500 mg/L时,莰烯醛肟对水稻纹枯病菌等9种植物病原真菌完全抑制,对松枯梢病菌和七叶树壳孢菌的抑制率达97%以上,当药液浓度降低时,莰烯醛肟对大部分病原菌的抑制率仍然超过百菌清500 mg/L时的抑制率。虽然莰烯醛肟烃基醚衍生物的抑菌活性较莰烯醛肟有所降低,但对毛竹枯梢病菌、梨链格孢菌和玉米赤霉病菌的抑制率皆高于(或等于)百菌清。     

Alpha-glucosidase inhibitory effect of mulberry (Morus alba) leaves on Caco-2

The effects of brewing time on dry weight content and alpha-glucosidase inhibitory active component released from mulberry (Morus alba) tea were studied. Different tea products showed significant differences in inhibitory activity against both sucrase and maltase. The most effective enzyme inhibition was observed when 3 to 5 min brewing time was applied in tea preparation. In a Caco-2 cell culture experiment the tea reduced the liberated glucose contents in both apical and basal sides of the cell monolayers. It can be concluded that hot water extract of mulberry leaves does have inhibitory effect against alpha-glucosidases, sucrase and maltase enzymes, and has a potential to be consumed as antidiabetic herb tea.     

西双版纳热区木霉的分离及抑菌活性初步研究

对采自西双版纳热区枯枝落叶上的木霉进行分离,共获得19株木霉(Trichoderma spp.)。抑菌活性测定结果表明,19株木霉的发酵液对3种病原真菌(Sclerotinia sclerotiorum,Botrytiscinerea Pers.,Colletotrichum sp.)均具有不同程度的抑制作用,其中菌株SWFC1291对3种病原真菌的抑菌率均超过了80%;SWFC1511对Botrytiscinerea Pers.的抑菌率达90%。19株木霉中,SWFC2470对红酵母(Rhodotorulasp.)的抑制效果较好,抑菌圈直径达到了2.65cm;SWFC2397,SWFC2470,SWFC3499和SWFC3568这4株菌对大肠杆菌(Escherichia coli)的抑制作用明显,其中SWFC3568的抑菌圈达到了1.60 cm。SWFC1925和SWFC2470两个菌株对红酵母和大肠杆菌均具有抑菌活性,其中SWFC2470菌株对两种菌的抑制作用较强。     

In vitro antifungal activities of longan (Dimocarpus longan Lour.) seed extract

Longan, Dimocarpus longan Lour., contains polyphenolic compounds which exhibit several pharmacological properties. This study aims to evaluate antifungal activities of longan fruit extract in comparison to its active compounds. The results showed that longan seed exhibited antifungal activity against the opportunistic yeasts (Candida species and Cryptococcus neoformans). In contrast, longan pulp and whole fruit did not demonstrate any inhibitory effects. Ellagic acid showed the most potent antifungal activity followed by corilagin and gallic acid, respectively. Ellagic acid inhibited Candida parapsilosis and C. neoformans more effectively than Candida krusei and also some Candida albicans clinical strains. Baidam cultivar possessed higher antifungal activity (MIC=500-4000 μg/ml) as it contained higher contents of ellagic acid and gallic acid than Edor (MIC=1000-8000 μg/ml). For antibacterial activity, only corilagin and gallic acid possessed weak to moderate inhibitory effects against Staphylococcus aureus and Streptococcus mutans, respectively. Longan seed was then applied in the oral care products. Longan effervescent granule (5% extract) significantly reduced adhesion of C. albicans to acrylic strips. Mouthwash containing 0.5% extract exhibited good antifungal activity compared to a commercial product. These findings indicated that longan seed extract and its polyphenolic compounds can be used as an antifungal agent in oral care products for the treatment of opportunistic yeast infection.     

青钱柳叶提取物对Caco-2细胞二糖酶活性的抑制作用

采用Caco-2细胞模型,分析了青钱柳Cyclocarya paliurus叶水提物、醇提后的水提物、95%醇提物、乙酸乙酯萃取物和正丁醇萃取物5种不同提取物对Caco-2细胞活力的影响及对Caco-2细胞上麦芽糖酶、蔗糖酶、乳糖酶3种二糖酶活性的抑制作用。结果表明,5种不同提取物中除95%醇提物对Caco-2细胞活力产生一定影响外,其余4种提取物对Caco-2细胞基本无毒性,在200 mg·L^-1浓度提取物范围内培养24～72 h后细胞仍能保持较高活力;对3种二糖酶活性抑制作用效果最好的为醇提后的水提物,尤其是对蔗糖酶和乳糖酶的抑制作用更为明显,最高的抑制率分别达到76.35%和60.13%,其次为乙酸乙酯萃取物,对乳糖酶的抑制率最高达54.41%。从青钱柳叶不同方法提取物的制备流程说明多糖类或中等极性的黄酮甙类有可能是青钱柳叶中抑制二糖酶活性的主要组成成分。     

Isolation and characterization of a germination inhibitor from leaves of Empetrum hermaphroditum hagerup

An extract of Empetrum hermaphroditum Hagerup leaves was examined for germination inhibitors using an assay based on germination of Populus tremula L. seeds. The substances were extracted in water and purified by solvent partitioning. The acidic ethyl acetate fraction, containing the major part of the inhibitory activity was purified by reversed‐phase high‐performance liquid chromatography. Two zones of inhibitory activity were detected, combined and further purified by normal‐phase HPLC. One major zone of inhibitory activity was thereafter detected and the substance in this fraction was crystallized and identified by nuclear magnetic resonance and gas chromatography‐mass spectrometry as 5‐methoxy‐3,3´‐dihydroxy‐dihydrostilbene or batatasin III. Ca. 100 mg of the substance was then, by sequential HPLC, isolated in crystalline form from E. hermaphroditum leaves. The inhibitory activity of the pure substance was compared with a crude water extract of E. hermaphroditum leaves. It was concluded that the pure substance exhibited ca. 28 % of the inhibitory activity of the crude extract. The difference in inhibitory activity might be explained by the presence of a glucosidic conjugate of 5‐methoxy‐3,3´‐dihydroxy‐dihydrostilbene in the crude extract.     

Evaluation of biological activities of extracts from 22 African tropical wood species

Heartwoods of 22 African tropical wood species were extracted with methanol and the contents of total phenolic compounds in these extracts were measured. Three bioassays were conducted to evaluate the antioxidant activity, tyrosinase inhibitory activity, and antifungal activity of the methanol extracts. The results indicated that the extracts from 13 species exhibited high antioxidant potential, and their inhibitory concentrations that caused 50% scavenging of the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical (IC₅₀) were less than 10 μg/ml. The crude extract from Cylicodiscus gabunensis showed the highest antioxidant activity, and was even higher than that of (+)-catechin, which is known as a potent antioxidant. There was a good correlation between the antioxidant activity and the content of total phenolic compounds, indicating that phenolic compounds played a predominant role in the antioxidant property of the wood extracts. Among all 22 species, only 1 species, Milicia excelsa, contained extractives that showed very high tyrosinase inhibitory activity. The extracts from 9 species showed high antifungal activity. No consistent relationship was observed between the tyrosinase inhibitory activity or antifungal activity and the content of total phenolics in the extracts. Part of this article was presented at the 56th Annual Meeting of the Japan Wood Research Society, Akita, August 2006     

Screening antiacne potency of Indonesian medicinal plants: antibacterial,lipase inhibition,and antioxidant activities

Indonesian medicinal plants were screened as potential sources of antiacne agents. The screening methods were performed using antibacterial assay against Propionibacterium acnes, lipase inhibitor assay, and antioxidant assay. The results showed that from 40 plant materials extracted with methanol and 50% ethanol in water, Caesalpinia sappan was the best extract based on the combined activities: antibacterial (minimum inhibitory concentration 0.13 mg/ml; minimum bactericidal concentration 0.25 mg/ml), lipase inhibitory [50% inhibitory concentration (IC₅₀) 120.0 μg/ml], and antioxidative (IC₅₀ 6.47 μg/ml). Another prospective extract is Intsia palembanica based on its lipase inhibitory activity (IC₅₀ 4.1 μg/ml) and antioxidant activity (IC₅₀ 3.87 μg/ml). Part of this report was presented at the 58th Annual Meeting of the Japan Wood Research Society, Tsukuba, March 2008     

Alpha-bulnesene, a PAF inhibitor isolated from the essential oil of Pogostemon cablin

Steam distilled essential oil from the aerial parts of Pogostemon cablin was analyzed by gas chromatography-mass spectrometry (GC-MS). Forty one compounds were identified of which alpha-guaiene (20.62%) and alpha-bulnesene (16.18%) were major constituents. Furthermore, fractionation of the essential oil from P. cablin guided by inhibitory activity against PAF-induced platelet aggregation led to the isolation of the sesquiterpene, alpha-bulnesene.