Isolation, structure elucidation, and biological activity of a new alkaloid from Zanthoxylum rhetsa

Several biologically active alkaloids (1-4, 6), including a new quinazoline-6-carboxylic acid (1), were isolated from the medicinal plant Zanthoxylum rhetsa, an evergreen tree, native to subtropical areas. Whereas the pharmacological properties of the plant extract and single constituents have been widely tested, we now show that all of the metabolites have antialgal activities, all but 6 are antibacterial, and 6 and the reduction product 5 (derived from 4) are also antifungal.     

Isolation and structure of sungucine: a new type of bisindoline alkaloid

From the roots of $\text{Strychnos icaja}$ Baill. an unsymmetrical dimeric alkaloid has been isolated and called sungucine. Its original structure has been established by X-Ray diffraction; UV, IR, MS and NMR data are also given.     

Isolation of a new carboline alkaloid from Trigonostemon lii

A new carboline alkaloid, 1-(7-methoxy-quinolinyl-4′-yl)-3,4-dihydro-β-carboline (1), was isolated from the leaves and twigs of Trigonostemon lii Y.T. Chang, together with three known ones, trigonostemonines C and D (2 and 3), and trigonoliimine A (4). Their structures were elucidated by spectroscopic analyses, including 2D-NMR techniques.     

Isolation of a new lycodine alkaloid from Lycopodium japonicum

A new lycodine alkaloid, N-methylhydroxypropyllycodine (1), was isolated from the club moss Lycopodium japonicum Thunb, together with five known compounds, N-methyllycodine (2), huperzinine (3), β-obscurine (4), α-obscurine (5) and des-N-methyl-α-obscurine (6). Their structures were elucidated by spectroscopic analyses, including 2D NMR techniques.     

Isolation and X-ray crystal structure of a securinega-type alkaloid from Phyllanthus niruri Linn

A securinega-type alkaloid epibubbialine was isolated from Phyllanthus niruri Linn. Its structure was established by spectroscopic methods and X-ray single-crystal diffraction analysis. Its crystal structure is reported herein for the first time.     

Isolation, X-ray crystallography, and computational studies of calydaphninone, a new alkaloid from Daphniphyllum calycillum

[structure: see text]. A new hexacyclic alkaloid, calydaphninone (1), containing a 4-azatricyclo[5.2.2.0(1,4)]undecan ring system, has been isolated from the leaves and twigs of Daphniphyllum calycillum (Daphniphyllaceae). Its structure was elucidated by spectral and crystallographic means. Furthermore, conformations of calydaphninone (1) in solution are discussed on the basis of NMR spectral analysis and computational (B3LYP/6-31G*) results.     

Isolation and structure determination of a new sesquiterpene lactone from Nauplius aquaticus

The aerial part of Nauplius aquaticus afforded a new sesquiterpene lactone with a humulanolide skeleton, 6,7,9,10-tetrahydroasteriscunolide (1), in addition to the known asteriscunolides A (2) and D (3). Their structures were established principally by two-dimensional NMR spectroscopy.     

Isolation and structure of a new sulphur-containing aminoacid from sea urchin eggs

Unfertilized sea urchin eggs (Paracentrotus lividus) contain, in addition to glutathione, a new low molecular weight thiol, 1-methyl-5-thiol-l-histidine ($\text{1}$) which was isolated and characterized as the disulphide $\text{2}$ by spectral and chemical evidence.     

Isolation, synthesis and photochemical properties of almazolone, a new indole alkaloid from a red alga of Senegal

An indole alkaloid bearing an oxazolone ring, christened almazolone, has been isolated from a new collection of Haraldiophyllum sp. from Dakar (Senegal), as an 88:12 mixture of (Z)/(E) stereoisomers. The relative ratio could be modified under controlled photochemical and thermal processes. The product (Z)-3-indolyl-2-(phenyl-propionylamino)-acrylic acid obtained by oxazolone ring opening has also been observed. Its formation has been confirmed by alkaline hydrolysis of (Z)-almazolone available from synthesis, where condensation of indole-3-carboxaldehyde with (3-phenylpropionylamino)-acetic acid represents the key step.     

两面针植物中的新生物碱7-去甲6-甲氧基-5,6-二氢白屈菜红碱的晶体结构

从两面针植物中分离得新生物碱7-去甲-6-甲氧基-5,6-二氢白屈菜红碱(C~2~1H~1~0O~5N的单晶结构已用直接法解出:空间群为P2t/c,晶能参数:a=14.213(7),b=17.347(3),c=7.513(9)A,β=101.40(13)°,z=4。对I≥3σ(I)的1876个独立反射, 用全矩阵最小二乘法修正到R=0.096和Rπ=0.077(单位权重)。     

Macleayine,a new alkaloid from Macleaya cordata

Macleayine (1),a new natural occurring alkaloid with a unique spiro[furanone-piperidinedione] framework,was isolated from the aerial parts of Macleaya cordata.Its unusual structure was established by extensive spectroscopic analyses,computer-assisted structure elucidation software (ACD/Structure Elucidator),quantum chemistry calculations and ECD calculation.The result of virtual molecular docking predicted the compound can enhance the effects of insulin,and may be used to treat type II diabetes.     

Macleayine,a new alkaloid from Madeaya cordata

Macleayine(1),a new natural occurring alkaloid with a unique spiro[furanone-piperidinedione]framework,was isolated from the aerial parts of Madeaya cordata.Its unusual structure was established by extensive spectroscopic analyses,computer-assisted structure elucidation software(ACD/Structure Elucidator),quantum chemistry calculations and ECD calculation.The result of virtual molecular docking predicted the compound can enhance the effects of insulin,and may be used to treat type II diabetes.     

Selagoline, a new alkaloid from Huperzia selago

A new natural product, named selagoline, and two known alkaloids, huperzine A and serratidine, were isolated from Huperzia selago (Lycopodiaceae) collected in Iceland. Their structures were determined using 600 and 800MHz one- and two-dimensional NMR methods supported by Fourier-transform mass spectrometry. Possible role of selagoline as a precursor of 5,15-oxidolycopodane, a component of the classical alkaloids L28 and L31, is discussed.