Gypsins A-D from Gypsophila arabica

Four new cyclopeptides, named gypsins A-D (1- 4), together with one known oleanane saponin, were isolated from the roots of Gypsophila arabica. The structures of cyclo(-Leu(1)-Pro(2)-Leu(3)-Trp(4)-Pro(5)-Gly(6)-) (1), cyclo(-Leu(1)-Pro(2)-Tyr(3)-Phe(4)-Pro(5)-Gly(6)-) (2), cyclo(-Ala(1)-Pro(2)-Tyr(3)-Leu(4)-Leu(5)-Pro (6)-Pro(7)-Ala(8)-) (3), and cyclo(-Leu(1)-Trp(2)-Pro(3)-Gly(4)-Gly(5)-Ser(6)-Ser(7)-) (4) were elucidated by 1D and 2D NMR spectroscopy including 1D-TOCSY, DQF-COSY, 2D-ROESY, HSQC, and HMBC experiments, as well as ESI tandem mass spectrometric fragmentation analysis and chemical evidence.     

Bioactive diterpenes and other constituents of Croton steenkampianus

A new indanone derivative (1) and two new diterpenoids (2 and 3), together with three known flavonoids, have been isolated from an ethanol extract of the leaves of Croton steenkampianus. The structure of 2 was solved by single-crystal X-ray diffraction analysis, whereas those of 1 and 3 were established mainly by 1D and 2D NMR spectroscopic methods. The isolated compounds were tested for their antiplasmodial activity and cytotoxicity. Antiplasmodial assays against chloroquine-susceptible strains (D10 and D6) and the chloroquine-resistant strains (Dd2 and W2) of Plasmodium falciparum showed that compound 2 gave moderate activities at 9.1-15.8 μM, while none of the compounds were cytotoxic against Vero cells.     

Geographic distribution of three alkaloid chemotypes of Croton lechleri

Three known alkaloids, isoboldine (2), norisoboldine (1), and magnoflorine (8), have been isolated for the first time from Croton lechleri, a source of the wound healing latex "sangre de grado". An HPLC system was developed, and a large number of latex and leaf samples of C. lechleri from 22 sites in northern Peru and Ecuador were analyzed to gain an understanding of the natural variation in alkaloid content for the species. Up to six alkaloids were found to occur in the leaves including, in addition to those listed above, thaliporphine (3), glaucine (4), and taspine (9), whereas the latex contained only 9. Taspine (9) is the component that has been previously found to be responsible for the wound healing activity of C. lechleri latex, and its mean concentration throughout the range examined was found to be 9% of the latex by dry weight. In addition, three chemotypes are defined based on the alkaloid content of the leaves, and the geographic distribution of these chemotypes is discussed along with a quantitative analysis of the alkaloid content as a function of chemotype.     

Bioactive compounds from the aerial parts of Brachystemma calycinum and structural revision of an octacyclopeptide

Four new cyclic peptides, brachystemins F-I (1-4), and 11 known compounds were isolated from the aerial parts of Brachystemma calycinum. The absolute configurations of compounds 1-4 were assigned using Marfey's method. The structure of compound 5 was revised from cyclo(Pro1-Phe2-Leu3-Ala?-Thr?-Pro?-Ala?-Gly?) to cyclo(Pro1-Pro2-Ala3-Gly?-Leu?-Ala?-Thr?-Phe?) with QTOF/MS and X-ray diffraction analysis. The N-containing compounds were assessed for their inhibitory effects on the secretion of monocyte chemokine ligand 2 (CCL-2), interleukin 6 (IL-6), and collagen IV against high-glucose-stimulated mesangial cells. Compound 5 was evaluated for its effects on collagen I, reactive oxygen species (ROS), superoxide anion (O?(??)) production, and cell viability in mesangial cells, and on nitric oxide (NO) production in macrophage cells.     

Three new sesquiterpenes from Croton arboreous

Three new sesquiterpenes, 5alpha,7alpha,10betaH-3-patchoulen-2-one (1), 5alpha,7alpha10betaH-4(14)-patchoulen-2alpha-ol (2), and 9alpha,10beta-dihydroxy-2beta,4beta-peroxy-1alpha,5beta,7alphaH-guaiane (3), were isolated from the aerial parts of Croton arboreous along with 14 known compounds. The structures of these compounds were determined on the bases of their spectroscopic data (IR, UV, OR, 1D and 2D NMR, and MS). The anti-inflammatory activity against ear edema in mice produced by 12-O-tetradecanoylphorbol-13-acetate (TPA) was evaluated for all the pure compounds and showed that compounds 4-7 are active.     

毛叶巴豆中的倍半萜类成分

从毛叶巴豆茎中分离得到2个倍半萜类化合物，其中化合物1为一个新化合物，应用HREI-MS，^1H-NMR，^13C-NMR，^1H-H COSY,HMQC，HMBC和NOESY等光谱测定了其结构，并命名为毛叶巴豆醇。然而，文献检索发现该结构被错误地鉴定为Homalomenol D，通过仔细分析文献报道的核磁数据并与化合物1比较，发现文献中Homalomenol D结构鉴定有误，应该修正为5-表毛叶巴豆醇。化合物2鉴定为日本刺参萜酮。     

Integerrimides A and B, cyclic heptapeptides from the latex of Jatropha integerrima

Two new cyclic heptapeptides, integerrimides A and B, have been isolated from the latex of Jatropha integerrima. Their structures were elucidated by using extensive 1D and 2D NMR, MS, and chemical degradation. At 50 microM both peptides 1 and 2 significantly inhibited neurite outgrowth in neuronal cell culture. They also partially inhibited proliferation of human IPC-298 melanoma cells as well as migration of human Capan II pancreatic carcinoma cells, but were inactive in HSV-1, antifungal, and antimalarial assays.     

Labdane and kaurane diterpenoids from Plectranthus fruticosus

Six new diterpenoids, three labdane and three kaurane derivatives, have been isolated from an acetone extract of Plectranthus fruticosus together with other already known substances. The structures of these compounds (1-5 and 7) were established mainly by spectroscopic means, particularly by 1D and 2D NMR studies, as well as by some chemical correlations with known diterpenoids. The physical and spectroscopic data of the derivative 11, obtained by hydrolysis of the labdane 2, were identical to those reported for a compound previously isolated from Croton joufra, to which structure 12 had been established erroneously by other authors. Several of the isolated compounds were tested as antimicrobial agents against three bacteria strains and one yeast strain, but only 4 showed a moderate inhibitory activity against Staphylococcus aureus.     

毛叶巴豆化学成分的研究

 目的研究大戟科(Euphorbiaceae)植物毛叶巴豆(Croton caudatus Geisel.var.tomentosus Hook.)茎中的化学成分。方法利用硅胶柱,凝胶柱色谱等常规分离技术分离纯化化合物,根据现代波谱学技术(MS,¹H-NMR,¹³C-NMR)进行结构鉴定。结果从毛叶巴豆茎的体积分数95%乙醇提取物中分离得到11个化合物,分别鉴定为:三十六烷酸乙酯(ethyl hexatriacontanoate,1),棕榈酸(palmic acid,2),硬脂酸(stearic acid,3),浙贝素(zheberiesinol,4),香草醛(vanillin,5),香草酸(vanillic acid,6),丁香酸(syringic acid,7),二十八烷酸(octacosanoic acid,8),琥珀酸(succinic acid,9),肌苷(inosine,10),异橙黄酮(isosinensetin,11)。结论所有化合物均为首次从该植物中分离得到,其中化合物4,7,9,10,11为首次从该属植物中分得。     

Insect antifeedants from Croton jatrophoides: structures of zumketol, zumsenin, and zumsenol

Three new A-seco limonoids, zumketol (1), zumsenin (2), and zumsenol (3), were isolated from a methanol extract of Croton jatrophoides by bioassay-guided fractionation, and their structures were determined by NMR analysis. The alpha-ketol 1 may be biosynthesized via the intramolecular acyloin condensation of a dicarboxylate intermediate.     

New diterpenes from Croton insularis

Two new diterpenes (1 and 2) have been isolated from the aerial parts of Croton insularis. Their structures have been established by NMR and mass spectral data, and the absolute configuration of 1 and related trachylobane diterpenes was determined through a series of chemical correlations.     

Tasnemoxides A-C, new cytotoxic cyclic norsesterterpene peroxides from the Red Sea sponge Diacarnus erythraenus

Tasnemoxides A-C (1-3), three new cytotoxic cyclic norsestertepene peroxides, were isolated from the Red Sea sponge Diacarnus erythraenus, together with the known compound sigmosceptrellin B (4). The structural determination of the isolated compounds was based on extensive 1D and 2D NMR studies and mass spectral determinations. Compounds 1-3 showed moderate cytotoxicity against three cancer cell lines.     

Two new chymotrypsin inhibitors isolated from the Cyanobacterium Microcystis aeruginosa NIES-88

Micropeptins 88-N (1) and 88-Y (2), new 3-amino-6-hydroxy-2-piperidone (Ahp)-containing cyclic depsipeptides, were isolated from Microcystis aeruginosa NIES-88. The structures were elucidated by analyses of HRFABMS, 1D and 2D NMR spectra, and chemical degradation. Micropeptins 88-N and 88-Y inhibited chymotrypsin. The inhibitory activities were closely related to the amino acid residue that was attached to the amino group of Ahp.     

Antimalarial and antituberculous poly-O-acylated jatrophane diterpenoids from Pedilanthus tithymaloides

Six new poly-O-acylated jatrophane diterpenes (1- 6) have been isolated along with five known compounds from the white latex of Pedilanthus tithymaloides. The structural identification was accomplished on the basis of 2D NMR and MS investigations. Some of these highly oxygenated jatrophane diterpenes possess a rare O-acetyl enol moiety. Compounds 1 and 3- 5 showed antiplasmodial activity with IC(50) values of 3.4-4.4 microg/mL and antimycobacterial activity against Mycobacterium tuberculosis with minimum inhibition concentration (MIC) values ranging from 12.5 to 100 microg/mL.     

Nitrogen-containing phorbol esters from Croton ciliatoglandulifer and their effects on cyclooxygenases-1 and -2

Four new phorbol derivatives, 12-O-[(2R)-N,N-dimethyl-3-methylbutanoyl]-4-deoxyphorbol 13-acetate (1), 12-O-[(2S)-N,N-dimethyl-3-methylbutanoyl]-4-deoxyphorbol 13-acetate (2), 12-O-[3-methyl-2-butenoyl]-4-deoxyphorbol 13-acetate (3), and 12-O-[(2R)-N,N-dimethyl-3-methylbutanoyl]phorbol 13-acetate (4), along with six known compounds, were isolated from the aerial parts of Croton ciliatoglandulifer. An anti-inflammatory activity of a hexane extract of this plant was demonstrated against ear edema in mice produced by 12-O-tetradecanoylphorbol 13-acetate, and compounds 1, 4, and 3beta-O-acetyloleanolic acid (5) were active when evaluated against cyclooxygenases-1 and -2.     

石山巴豆枝叶中1个新的降克罗烷二萜

目的研究石山巴豆Crotoneuryphyllus枝叶中的二萜成分。方法综合运用硅胶、MCI、高效液相等色谱技术进行化合物的分离纯化,根据化合物的波谱数据分析与文献比对进行结构鉴定。结果从石山巴豆枝叶95%提取物的石油醚部位中分离得到4个化合物,分别鉴定为crotoeurin D(1)、mallotucin C(2)、mallotucin D(3)、plaunotol(4)。结论化合物1为新的降克罗烷二萜,命名为石山巴豆素D;化合物2～4均为首次从该植物中分离得到。     

Alpha-glucosidase inhibitor from Kothala-himbutu (Salacia reticulata WIGHT)

A polyhydroxylated cyclic 13-membered sulfoxide (1) was isolated from an aqueous extract of Kothala-himbutu ( Salacia reticulata WIGHT). The structure of compound 1 was elucidated by 1D and 2D NMR and APCI-MS methods. The alpha-glucosidase inhibitory activity of compound 1 (IC 50: maltase, 0.227 microM; sucrase, 0.186 microM; isomaltase, 0.099 microM) was much greater than the inhibitory activity of salacinol and kotalanol, which were previously isolated from Kothala-himbutu.     

Psychrophilin A and cycloaspeptide D, novel cyclic peptides from the psychrotolerant fungus Penicillium ribeum

Two fungal metabolites, psychrophilin A (1) and cycloaspeptide D (2), together with the known cycloaspeptide A (3) were isolated from the psychrotolerant fungus Penicillium ribeum using high-speed countercurrent chromatography (HSCCC) and preparative HPLC. The structures were determined from 1D and 2D NMR techniques, HREIMS, tandem mass spectrometry (ESMS/MS), and X-ray crystallography. The amino acid residues of psychrophilin A (1) and cycloaspeptide D (2) were all found to possess the l configuration by Marfey's method. Psychrophilin A (1) is the first natural cyclic peptide containing a nitro group instead of an amino group.     

New cyclic peptide and bisindolyl benzenoid metabolites from the sclerotia of Aspergillus sclerotiorum

Scleramide (1), a new cyclic hexapeptide, and a new oxidized bisindolyl benzenoid derivative (2' '-oxoasterriquinol D methyl ether, 2) were isolated from extracts of the sclerotia of Aspergillus sclerotiorum (NRRL 5167). The structures of these compounds were determined by analysis of 1D and 2D NMR experiments.     

New antimycobacterial and antimalarial 8,9-secokaurane diterpenes from Croton kongensis

Two new 8,9-secokaurane diterpenes, ent-8,9-seco-7alpha,11beta-diacetoxykaura-8(14),16-dien-9,15-dione (1) and ent-8,9-seco-8,14-epoxy-7alpha-hydroxy-11beta-acetoxy-16-kauren-9,15-dione (2), together with two known compounds, ent-8,9-seco-7alpha-hydroxy-11beta-acetoxykaura-8(14),16-dien-9,15-dione (3) and ent-7beta-hydroxy-15-oxokaur-16-en-18-yl acetate, were isolated from Croton kongensis. This is the first report on the presence of 8,9-secokauranes in the plant genus Croton. Diterpenes 1-3 exhibited antimycobacterial activity with minimum inhibitory concentrations (MICs) of 25.0, 6.25, and 6.25 microg/mL, respectively, and possessed antimalarial activity with IC(50) ranges of 1.0-2.8 microg/mL. They also demonstrated comparable cytotoxicity toward the Vero (IC(50) ranged from 0.9 to 3.2 microg/mL), KB (IC(50) from 1.2 to 13.8 microg/mL), and BC cell lines (IC(50) from 1.1 to 2.2 microg/mL, except for compound 1, which was inactive against BC cells).