Trangmolins A–F with an Unprecedented Structural Plasticity of the Rings A and B: New Insight into Limonoid Biosynthesis

The absolute stereostructures of trangmolins A–F ( 1 – 6 ), limonoids with three new and one known topologies of the rings A and B, were unambiguously determined by NMR spectroscopic investigations, single‐crystal XRD analysis, and quantum‐chemical electronic circular dichroism calculations. Compounds 1 – 3 contain a hexahydro‐1H‐inden‐4‐one motif, compound 4 comprises a hexahydro‐2,6‐methanobenzofuran‐7‐one cage, and compound 5 consists of a hexahydro‐2H‐2,8‐epoxychromene scaffold. The C1?C30 linkage in 1 – 3 and the C3?C30 connection in 4 form two unprecedented types of ring A/B‐fused carbobicyclic cores: viii and ix . The oxidative cleavage of the C2?C3 bond in 5 and heterocyclization in 4 and 5 constitute the unprecedented tricyclic 6/6/5 ring A/B¹/B²‐ and 6/5/6 ring A¹A²/B‐fused topologies, respectively, which are uncovered, for the first time, in the construction of limonoid architectures. The diverse cyclization patterns of 1 – 6 reveal an unparalleled structural plasticity of rings A and B in limonoid biosynthesis.     

Fatty acid derivatives from the halotolerant fungus Cladosporium cladosporioides

Halotolerant fungus Cladosporium cladosporioides OUCMDZ‐187 was isolated from the mangrove plant Rhizophora stylosa collected in Shankou, Guangxi Province of China. Three new fatty acid esters cladosporesters A–C ( 1 – 3 ) and 5 new fatty acids cladosporacids A–E ( 4 – 8 ) were isolated from the ethyl acetate extract of the fermentation broth of OUCMDZ‐187 in a hypersaline (10% salt) medium. Their structures were elucidated by UV, IR, MS, specific rotation, and 1D and 2D NMR data.     

多种金属离子对一株双齿相手蟹肠道共生真菌生长代谢影响的研究

对一株双齿相手蟹肠道共生真菌Sporothrixsp．（ZJSEF-7）,测定了12种金属离子对该菌生长代谢的影响。结果表明,Fe^3＋、K^＋、Mn^2＋、Mg^2＋、Ca^2＋和Sb^3＋可明显促进菌体的生长;Cu^2＋、Sn^2＋和Pb^2＋对菌体生长没有明显的影响;Fe^2＋对菌体生长有强的抑制作用;Al^3＋和Zn^2＋完全抑制菌体生长。相手蟹共生菌对部分重金属显示了一定的抗性和强的化学防御功能,深入研究其作用机制,将有助于了解相手蟹共生菌的生物学本质及其生态学作用,对于保护红树林生态环境具有重要的意义。     

A new isochroman from the marine endophytic fungus 1893#

A new isochroman, 6-hydroxy-3-methylisochroman-5-carboxylic acid, and six known compounds were isolated from the culture of marine-derived mangrove fungus 1893#. Their structures were elucidated by analysis of spectroscopic data. Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 114–116, March–April, 2006.     

Crystal Structure of a Marine Natural Compound, Anhydrofusarubin

One marine natural compound, anhydrofusarubin, was isolated from the endophytic fungus No. B77 from the mangrove tree on the South China Sea coast. It was the first time that such a compound was isolated from marine fungus. The structure was identified by NMR data and mass spectrometry （MS）. In addition, its structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in triclinic, space group P1^- with a = 8.3185（15）, b = 12.397（2）, c = 13.767（3） A, α = 65.692（3）, β = 79.266（3）, γ= 75.692（3）°, C15H12O6, Mr= 288.24, V = 1248.0（4） A^3, Z = 4, Dc = 1.534 g/cm^3, F（000） = 600, μ = 0.120 mm^-1, the final R = 0.0459 and wR = 0.1184 for 5360 observed reflections （I 〉 2σ（I））. In the primary bioassay, the title compound shows strong inhibitory activity against Gram-positive bacteria Staphyococcus aureus （ATCC27154） with the MIC value of 12.5 μg/mL.     

Isolation, structure elucidation, and mutagenicity of four alternariol derivatives produced by the mangrove endophytic fungus No. 2240

A new alternariol derivative, 2240B (1), together with alternariol (2), alternariol 4,10-dimethyl ether (3), and alternariol 4-methyl ether (4), was isolated from the ethyl acetate extract of the liquid medium GYT of No. 2240, the mangrove endophytic fungus from the South China Sea Coast. The structure of compound 1 was unambiguously elucidated as alternariol 4-methyl-10-acethyl ester by spectra including one/two-dimensional NMR, HREIMS, IR, and UV. The structures of compounds 2–4 were also established by spectroscopic analyses and comparison with related literature data. The anticancer tests showed that compounds 2 and 4 had strong activities against KB and KBv200 cells with IC₅₀ values of 3.17, 3.12, and 4.82, 4.94 μg/mL, while compounds 1 and 3 exhibited weak activities against the two kinds of tumor lines with IC₅₀ values of more than 50 μg/mL. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 235–238, May–June, 2008.     

从红树林内源真菌2526#分离到Sterigmatocystin

从海洋资源中寻找药物已越来越受到重视 ,已有的研究表明海洋资源有可能成为治疗人类疑难病症和延年益寿药物的丰富源泉[1] 。本研究组在从海洋微生物筛选新药的过程中 ,已发现多种结构奇特而具有强生理活性的化合物[2～ 4 ] 。Ｓｔｅｒｉｇｍａｔｏｃｙｓｔｉｎ最早分离自陆生真菌Ａｓｐｅｒｇｉｌｌｕｓｖｅｒｓｉｃｏｌｏｒ的代谢产物[5] ,随后人们对其结构、生源合成及药理活性进行了广泛的研究。结果表明 ,ｓｔｅｒｉｇｍａｔｏｃｙｓｔｉｎ是细胞毒性更强的化合物ＡｆｌａｔｏｘｉｎＢ1的生源合成前体。本文报道从采自香港红树Ａｖｉ…     

湛江湾红树林湿地土壤重金属含量分析及污染评价

采用电感耦合等离子体发射光谱仪(ICP-AES)和电感耦合等离子体质谱仪(ICP-MS)对湛江湾红树林湿地土壤中8种重金属(As、Cu、Cd、Cr、Hg、Ni、Pb、Zn)含量进行测定,采用单因子污染指数法、内梅罗综合污染指数法和地累积指数法进行污染评价,并结合相关性分析和因子分析方法探讨重金属来源。结果表明:除Ni外,其余7种重金属元素含量平均值均未超过国家土壤环境质量标准(GB15618-2018);但Ni、Zn、Cu、Hg、As和Cd元素均超过广东砖红壤环境背景值,其中As、Ni、Hg和Zn元素超标情况严重。8种重金属元素内梅罗综合污染指数评价结果为0.373~22.576,平均值为3.378,整体处于重度污染;单因子污染指数依次为Ni>Hg>Zn>Cd>As>Cu>Pb>Cr。单个重金属元素地累积指数评价结果与内梅罗综合污染评价相一致,均显示红树林土壤中Hg、Zn和Ni元素污染严重,是影响研究区土壤环境质量的重要因素。从站位看,位于湾内北部的北涯村、观海长廊以及西部的世乔村站位污染较严重,高污染站位约占总站位数的33%,主要为Cd、Hg和Zn。统计分析结果显示,除Ni外,湛江湾红树林土壤中7种重金属元素之间显著相关;结合实地调查结果推测重金属污染主要来自工业污染、船舶排污、养殖排污、生活排污及农业面源污染等人为活动的输入,其次为自然因子的输入。     

Isolation and crystal structure of (−)-byssochlamic acid from mangrove fungus (strain no. k38)

(−)-Byssochlamic acid (1) was isolated from mangrove fungus (strain No. k38) from the South China Sea coast. This is the first time that 1 was found in nature. Its structure was confirmed by spectra data and X-ray diffraction analysis. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 241–242, May–June, 2006.     

光纤荧光法对吸附于红树叶片表面上荧蒽的测定

利用光纤荧光法实现了吸附于白骨壤(Am)、海漆(Ea)、秋茄(Kc)、桐花树(Ac)和老鼠簕(Ai)叶片表面上荧蒽(Fla)的定量测定.所建方法测定吸附于Am、Ea、Kc、Ac和Ai叶片表面上Fla的线性范围分别为2.5 ～500、2.0 ～600、4.5 ～1 100、15 ～600、3.5 ～450 ng/spot,相应的检出限分别为0.91、0.63、1.12、3.52、1.40 ng/spot,方法的相对标准偏差小于7.8%(n=15),加标回收率分别为97% ～108%、78% ～95%、77% ～90%、84% ～108%和78% ～102%.利用所建方法考察了5种红树叶片正反面吸附不同量Fla的信号强度随时间的变化情况.结果表明:在200 min内,叶片正反面上Fla的信号均发生不同程度的衰减,且反面的信号衰减率大于正面;5种红树叶片正反面对Fla的吸附特性均不同;吸附于叶片正面的Fla多残留在叶片表面,而吸附于叶片反面的Fla易向叶片内部迁移.