植物内生真菌抗肿瘤活性菌株的筛选

从三尖杉、南方红豆杉及香榧中分离到172株植物内生真菌,利用抗肿瘤体外细胞毒筛选模型（MTT法）对其进行活性检测,结果表明,25株内生真菌（占总分离菌株的14.5%)对KB（人口腔上皮癌）或HL-60（人白血病）细胞具有显著的抑制活性。三尖杉、南方红豆杉及香榧内生赵菌的抗肿瘤活性菌株占各供测菌株的3.3%,19.6%和8.6%。其中7个菌株的细胞毒ID50为1,000以上,占总供测菌株的4.1%,抗肿瘤活性菌株主要分布在拟青霉属及头孢霉属中。     

墨西哥仙人掌植物内生真菌的研究Ⅰ.内生真菌分离及其抗菌活性筛选

从一种墨西哥仙人掌[Opuntiamicrodasys(Lehm .)Pfeiff]的肉质茎中分离获得31株内生真菌,经形态观察分类鉴定为3个目、3个科、14个属。同时选择2 2种病原微生物作为指示菌进行抑菌试验,研究其抗菌活性。结果表明:3株仙人掌内生真菌分别对细菌、植物病原真菌和皮肤致病真菌多种病原微生物有较为明显的抑制生长作用。     

红树植物内生真菌的分离鉴定及抗菌活性菌株的筛选

本文对厦门集美红树植物无瓣海桑(Sonneratia apetala),海马齿(Sesuvium portulacastrum)和秋茄(Kan-delia candel)的多个部位进行内生真菌的分离和形态鉴定,并采用菌饼法对分离到的内生真菌进行抗菌活性筛选。结果显示,从3种红树植物的根、茎、叶中分离得到25株内生真菌,分别隶属8个类群,以链格孢属和曲霉属为主,分别占菌株总数的28.0%和24.0%;有19株菌株对至少一种指示菌有抑制作用,占菌株总数的76.0%。研究结果表明,红树植物来源的内生真菌数量多,种属丰富,同时具有良好的抗菌活性,是研究抗菌活性化合物的重要资源。     

植物内生真菌杀螺活性菌株筛选

分别从醉鱼草和水菖蒲中分离出99、103株内生真菌,按照WHO杀螺剂浸泡试验法观察不同内生真菌以及不同浓度发酵液杀螺效果.用河虾急性毒性试验评价其对非靶水生生物毒性.结果表明LL3026、S38、S21菌株发酵液有较高的杀螺活性,发酵液浓度为10%时,钉螺死亡率为100.0%;对河虾急性毒性较小.     

虎杖内生真菌的分离及产抗菌活性物质的筛选

从植物虎杖(Polygonum cuspidatum Sieb.et Zucc.)的根状茎中分离出24株内生真菌,分别对其液体发酵液进行抗菌活性检测,结果筛选出3株内生真菌具有抗菌活性,它们分别属于曲霉属、青霉属和无孢菌类。     

云南重楼植物内生真菌的分离及抗菌活性筛选

从云南重楼[Paris polyphylla Smithvar.yunnnanensis(Franch.)Hand.Mazz.]块状茎中分离出166株内生真菌,对其进行形态分类鉴定归于4目,6科,20个属,体现了云南重楼植物内生真菌的生物多样性特征。同时,选择与人类和植物相关的37株病原微生物作为抗菌活性筛选指示菌,进行了云南重楼植物内生真菌抗菌活性的初步研究。结果表明,4株内生真菌对细菌、植物致病真菌、皮肤致病真菌多种病原微生物具有显著抑制生长的作用。     

木本曼陀罗内生真菌抗菌活性的筛选研究

从木本曼陀罗植物内生真菌中筛选高效抗菌活性的菌株。选择与人类和植物相关的36株病原微生物,分别对分离自木本曼陀罗(Datura arborea L.)植物的内生真菌77株进行了发酵代谢产物的抗菌活性筛选研究。结果显示:对细菌病原菌、皮肤致病真菌、植物致病真菌有抑制作用的内生真菌分别有24,9,17株,其中5株内生真菌对10种以上的供试病原菌有明显的抑制作用,活性最好的1株对20种病原菌有较强抑制活性,最大抑菌圈直径达48mm。这说明木本曼陀罗植物内生真菌抗菌能力较强,抗菌谱较广。     

抗植物病原真菌紫叶小檗内生真菌的筛选和鉴定

对紫叶小檗根、茎、叶和果实中分离纯化得到的28株内生真菌进行液体培养,培养物烘干研磨后用丙酮浸提,测定各提取物对5种供试植物病原真菌的抑菌活性,对抗菌谱较广的菌株进行分子鉴定,并分别测定其胞内、胞外代谢产物的抑菌活性.结果显示:(1)紫叶小檗25株内生真菌中有5株菌(R3、S4、L6、F2、F6)的抗菌谱较广,其中,茎中的内生菌S4抑菌活性最强,对5种植物病原真菌的抑菌活性均大于90％,对马铃薯干腐病菌的抑菌率最高达93.06％.(2)经鉴定S4为子囊菌门的Para phaeos phaeria属真菌.(3)S4菌丝体丙酮提取液对马铃薯干腐病菌的抑菌率随其浓度(加入体积)的增加而增大,呈正相关线性关系(y=15.334x+14.618,r=0.99),而S4发酵液对马铃薯干腐病菌的抑菌率随其浓度(加入体积)的增加而减小,呈负相关线性关系(y=-20.196x+64.984,r=0.99),即在较高浓度时促进病原菌生长.研究表明,紫叶小檗内生真菌S4菌株的抑菌活性成分主要为胞内代谢产物.     

芦荟植物内生真菌的研究Ⅱ．抗菌活性初探

对从中华芦荟 [AloeveraL .varChinese (HawBerg) ]、元江芦荟 (A .yuanjiangensisXiong&Zhengsp .nov .)及库拉索芦荟 (A .barbadsisMill.)的根、叶、花柄、花中 ,分离的 88株内生真菌 ,作了革兰氏阳性和阴性抑菌试验 ,研究了其抗菌活性。结果表明 ,芦荟植物不同种类、不同部位内生真菌的抗菌活性存在有差异。     

杜仲内生真菌的抑菌活性筛选

以金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌为测试菌种。对杜仲(Eucommia ulmoides Oliv.)根、茎、叶中分离出的20株内生真菌及其次生代谢物进行抗菌活性筛选。结果表明：有15个菌株至少对1种实验细菌具有抑菌活性,19株的代谢产物至少对1种实验细菌具有抑菌活性,其中有3株内生真菌及其次生代谢产物对测试病原细菌均有较强抑制作用。     

Potent Limonoid Insect Antifeedant from Melia azedarach

Systematic fractionation of a fruit extract from Argentine Melia azedarach L., which was monitored by an insect antifeedant bioassay, led to the isolation of meliartenin, a limonoid antifeedant, which existed as a mixture of two interchangeable isomers. At 4 μg/cm² and 1 μg/cm², the isomeric mixture was as active as azadirachtin in strongly inhibiting the larval feeding of Epilachna paenulata Germ. (Coleoptera: Coccinellidae) and the polyphagous pest, Spodoptera eridania (Lepidoptera: Noctuidae), respectively.     

Endophytic fungi from Melia azedarach

A collection of endophytic fungi was obtained from living apparently symptomless roots, stems, leaves and fruits of Melia azedarach. This is an exotic tree introduced into Brazil from Asia and is a producer of insecticidal compounds. It grows very well and is apparently resistant to many pathogens. Each segment from the plant was sampled during two periods. A total of 55 fungal isolates were recovered. Hyphomycetes were more prevalent than Ascomycetes, Coelomycetes and Basidiomycetes. The genera Aspergillus and Penicillium were the most common in the plant.     

Two New Limonoids from the Fruits of Melia azedarach (Meliaceae)

Two new limonoids, trichilinin M ( 1 ) and ohchinin benzoate ( 2 ), along with two known limonoids, 12-hydroxyamoorastatone ( 3 ) and mesendanin H ( 4 ), were isolated from the fruits of Melia azedarach Linn. The structures of new limonoids were determined by analyses of HR-ESI-MS, 1D and 2D NMR (HSQC, HMBC and NOESY) data. All compounds were evaluated against human pancreatic cancer PANC1 cells and the results showed that compounds 3 – 4 exhibited substantial cytotoxic activity ( 3 : IC₅₀=4.55 μM; 4 : IC₅₀=7.54 μM), and compounds 1 – 2 exhibited moderate cytotoxicity ( 1 : IC₅₀=27.06 μM; 2 : IC₅₀=21.17 μM).     

Phytochemical Investigations and In Vitro Bioactivity Screening on Melia azedarach L. Leaves Extract from Nepal

Melia azedarach is a common tree used in the traditional medicine of Nepal. In this work, leaves were considered as source of bioactive constituents and composition of methanol extract was evaluated and compared with starting plant material. Flavonoid glycosides and limonoids were identified and quantified by HPLC-DAD-MSⁿ approaches in dried leaves and methanolic extract, while HPLC-APCI-MSⁿ and GC/MS analysis were used to study phytosterol and lipid compositions. β-Sitosterol and rutin were the most abundant constituents. HPLC-APCI-MSⁿ and HPLC-DAD-MSⁿ analysis revealed high levels of phytosterols and flavonoids in methanolic extract accounting 9.6 and 7.5 % on the dried weight, respectively. On the other hand, HPLC/MSⁿ data revealed that limonoid constituents were in minor amount in the extract <0.1 %, compared with leaves (0.7 %) indicating that degradation occurred during extraction or concentration procedures. The methanol extract was subjected to different bioassays, and antioxidant activity was evaluated. Limited inhibitory activity on acetyl and butyryl cholinesterase, as well as on amylase were detected. Moreover, tyrosinase inhibition was significant resulting in 131.57±0.51 mg kojic acid equivalents/g of dried methanol extract, suggesting possible use of this M. azedarach extract in skin hyperpigmentation conditions. Moderate cytotoxic activity, with IC₅₀ of 26.4 μg/mL was observed against human ovarian cancer cell lines (2008 cells). Our findings indicate that the Nepalese M. azedarach leaves can be considered as valuable starting material for the extraction of phenolics and phytosterols, yielding extracts with possible cosmetic and pharmaceutical applications.     

苦楝多糖羧甲基化及抗氧化性的研究

植物多糖及其衍生物对人类健康的种种作用逐渐被发现和重视,本论文从成熟苦楝果肉中提取多糖,研究多糖羧甲基化的条件,并比较了羧甲基前后抗氧化能力。     

苦楝果多糖的分离纯化及组成分析

利用水提醇沉法提取苦楝果实中的多糖,经DEAE-52柱层析分离,得到MP1、MP2和MP3三个多糖组分,用Sephadex G-100凝胶色谱柱对MP1进行纯化鉴定,结果显示为单一峰。借助气质联用仪,对苦楝粗多糖和组分MP1进行了成分分析。红外光谱分析表明苦楝多糖的单糖残基以吡喃环和呋喃环的形式存在。     

Toxic polyketides produced by Fusarium sp., an endophytic fungus isolated from Melia azedarach

A new isocoumarin derivative named fusariumin (1), together with two known related resorcylic acid lactones aigialomycin D (2) and pochonin N (3), has been isolated from the cultures of Fusarium sp. LN-10, an endophytic fungus originated from the leaves of Melia azedarach. Their structures were established on the basis of extensive spectroscopic analyzes including 1D- and 2D- NMR (¹H-¹H COSY, HSQC, HMBC, and NOESY) experiments. Compounds 1-3 displayed significant growth inhibitory activity against the brine shrimp (Artemia salina).     

Clonal strategies of a woody weed: Melia azedarach

Melia azedarach L., a weedy tree that typically reproduces by seeds, may exhibit clonal growth following disturbance (e.g. fire, herbivory, animal injury). A dynamic and holistic study (sensu Hallé et al., 1978) was carried out in order to determine the architecture and the vegetative growth strategies, in plants collected from undisturbed and disturbed areas in the ‘El Palmar’ National Park. The architectural and morphological observations can be summarized as follows: (a) Tree architecture is determined by a monopodial trunk that produces tiers of orthotropic monopodial branches. (b) The root system consists of a tap root with woody primary lateral roots that exhibit plagiotropic growth and are typically found within the first few centimeters (ca. 4 cm) of the soil profile. (c) Root buds were produced in all (fire treated and control) plagiotropic root cuts when incubated under controlled conditions. Root suckers developed from the differentiation of parenchymatous cells produced by meristematic activity in the cambial zone. The ecological implications of vegetative reproduction on the invasive capacity of this species are discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Biofabrication of zinc oxide nanoparticles from Melia azedarach and its potential in controlling soybean seed-borne phytopathogenic fungi

Present study, report the biofabrication of zinc oxide nanoparticles from aqueous leaf extract of Melia azedarach (MaZnO-NPs) through solution combustion method and their novel application in preventing the growth of seed-borne fungal pathogens of soybean (Cladosporium cladosporioides and Fusarium oxysporum). The standard blotter method was employed to isolate fungi and was identified through molecular techniques. The characterization of MaZnO-NPs was carried out by UV–Vis spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) equipped with Energy Dispersive Spectroscopy (EDS) and Transmission Electron Microscopy (TEM). The physicochemical characterization confirmed the particles were of high purity and nano size (30–40 nm) with a hexagonal shape. The synthesized MaZnO-NPs inhibited the growth of C. cladosporioides and F. oxysporum in a dose dependent manner. Biomass, ergosterol, lipid peroxidation, intracellular reactive oxygen species and membrane integrity determination upon MaZnO-NPs treatment offered significant activities there by confirming the mechanism of action against the test pathogens. In conclusion, due to the effectiveness of MaZnO-NPs in controlling the growth of C. cladosporioides and F. oxysporum, the synthesized MaZnO-NPs provides insight towards their potential application in agriculture and food industries.