Search

Two new Erythrina alkaloid glycosides, 1 and 2, and three new diarylpropanoid glycosides 12–14 together with nine known compounds were isolated from the MeOH extracts of the seeds of Erythrina velutina. The structures and absolute configurations of these new compounds were elucidated through comprehensive spectroscopic analyses as well as experimental and calculated ECD data. The inhibitory potency of these compounds against nitric oxide production in LPS-induced RAW 264.7 cells and the cytotoxicity of these compounds against the HeLa and HL-60 human cancer cell lines were also discussed.

From the bark of Ladenbergia hexandra Klotzsch, ten triterpenoid glycosides were isolated along with five known compounds, and their structures were determined based on extensive NMR and mass spectroscopic, GC and HPLC analyses. Some triterpenoid glycosides contained 6-deoxy-D-allose or D-allose as a sugar moiety. The absolute stereochemical assignment of the sugars was determined by comparison with synthetic samples, as well as by GC and HPLC analysis.

Five new furanocassane-type diterpenoids, sucupiranins M–Q (1–5) were isolated from the seeds of Bowdichia virgilioides. Their structures and stereo chemistries were elucidated on the basis of spectroscopic analyses including HRESIMS, 2D NMR (1H-1H COSY, HSQC, HMBC, and NOESY), and ECD spectra.

A new arylbenzofuran, 3',5'-dihydroxy-6-methoxy-7-prenyl-2-arylbenzofuran (1), and 25 known compounds, including moracin R (2), moracin C (3), moracin O (4), moracin P (5), artoindonesianin O (6), moracin D (7), alabafuran A (8), mulberrofuran L (9), mulberrofuran Y (10), kuwanon A (11), kuwanon C (12), kuwanon T (13), morusin (14), kuwanon E (15), sanggenon F (16), betulinic acid (17), uvaol (18), ursolic acid (19), β-sitosterol (20), oxyresveratrol 2-O-β-D-glucopyranoside (21), mulberroside A (22), mulberroside B (23), 5,7-dihydroxycoumarin 7-O-β-D-glucopyranoside (24), 5,7-dihydroxycoumarin 7-O-β-D-apiofuranosyl-(1→6)-O-β-D-glucopyranoside (25) and adenosine (26), were isolated from Morus alba var. multicaulis Perro. (Moraceae). Their structures were determined by spectroscopic methods. The prenyl-flavonoids 11-14, 16, triterpenoids 17,18 and 20 showed significant inhibitory activity towards the differentiation of 3T3-L1 adipocytes. The arylbenzofurans 1-10 and prenyl-flavonoids 11-16 also showed significant nitric oxide (NO) production inhibitory effects in RAW264.7 cells.

New benzophenone and flavonol galloyl glycosides were isolated from an 80% MeOH extract of Psidium guajava L. (Myrtaceae) together with five known quercetin glycosides. The structures of the novel glycosides were elucidated to be 2,4,6-trihydroxybenzophenone 4-O-(6''-O-galloyl)-beta-D: -glucopyranoside (1, guavinoside A), 2,4,6-trihydroxy-3,5-dimethylbenzophenone 4-O-(6''-O-galloyl)-beta-D: -glucopyranoside (2, guavinoside B), and quercetin 3-O-(5''-O-galloyl)-alpha-L: -arabinofuranoside (3, guavinoside C) by NMR, MS, UV, and IR spectroscopies. Isolated phenolic glycosides showed significant inhibitory activities against histamine release from rat peritoneal mast cells, and nitric oxide production from a murine macrophage-like cell line, RAW 264.7.

A new diterpenoid with a rearranged skeleton, prattinin A (1), was isolated along with five known compounds (2–6) from the roots of Salvia prattii. The structure of 1 bearing a methyl group at the C-5 position was established by extensive spectroscopic analyses and the absolute configuration of 1 was elucidated by comparing the calculated and experimental electronic circular dichroism (ECD) spectra. Compounds 1, 3, 4, and 5 exhibited moderate or weak cytotoxicity against HL-60 and HeLa cell lines.

The biosynthesis of lactacystin, a new microbial metabolite which induces differentiation of neuroblastoma cells, was studied by the feeding experiments of various 13C-labeled compounds and NMR spectroscopic analysis. The feeding experiments showed that lactacystin consists of three containing gamma-lactam moiety arises by a condensation between methylmalonic semialdehyde and C alpha position of L-leucine, followed by intramolecular cyclization. Two diastereotopic methyls, C-11 and C-12 of lactacystin were found to originate from the pro-R and pro-S methyls of leucine, respectively, as shown by incorporating a new type of chiral 13C-labeled L-leucine.

Biosynthetic pathway of lactacystin and its stereochemical aspect were investigated by feeding experiments of 13 C enriched compounds.

The structure of the anticoccidial antibiotic xanthoquinodin A1(1), isolated from Humicola sp. FO-888, was elucidated by 1H- and 13C-NMR experiments. It contains a new type of xanthone and anthraquinone conjugate system.

The structures of xanthoquinodins A1, A2, A3, B1, and B2, anticoccidial antibiotics, produced by Humicola sp. FO-888 were confirmed by analyzing 13 C-labeled xanthoquinodins prepared biosynthetically in 13 C-labeled precursor feeding experiments on the basis of extensive spectroscopic techniques including 1 H- 1 H COSY, 13 C- 1 H COSY, andHMBC. Xanthoquinodins are the first heterodimers of octaketide-derived xanthone and anthraquinone monomers connected in an «end-to-body» fashion. The stereochemistry of xanthoquinodin B2 was determined by NMR including NOE measurements. Accordingly, the stereochemistry of xanthoquinodins A1, A2, and B1 was also deduced by studying the mechanism of interconversion among xanthoquinodins

The structures of xanthoquinodins A1, A2, A3, B1, and B2, anticoccidial antibiotics, produced by Humicola sp. FO-888 were confirmed by analyzing 13 C-labeled xanthoquinodins prepared biosynthetically in 13 C-labeled precursor feeding experiments on the basis of extensive spectroscopic techniques including 1 H- 1 H COSY, 13 C- 1 H COSY, andHMBC. Xanthoquinodins are the first heterodimers of octaketide-derived xanthone and anthraquinone monomers connected in an «end-to-body» fashion. The stereochemistry of xanthoquinodin B2 was determined by NMR including NOE measurements. Accordingly, the stereochemistry of xanthoquinodins A1, A2, and B1 was also deduced by studying the mechanism of interconversion among xanthoquinodins

Several isochromophilone analogues were synthesized from sclerotiorin (1) by Wittig reactions and aldol condensation reaction. The structures of the products were elucidated from MS, elemental analysis, 1H NMR and 13C NMR spectra, and their inhibitory activities against gp!20-CD4 binding were determined.

Novel brominated and halogen-less azaphilone (oxoisochromane) derivatives, 5-bromoochrephilone and dechloroisochromophilone IV, and known derivatives, dechloroisochromophilone III and isorotiorin, were isolated from the culture broth of a producing organism of isochromophilones I and II (azaphilones inhibiting gp120-CD4 binding), Penicillium multicolor FO-2338, fermented in a medium containing potassium bromide. Nineteen azaphilone-related compounds isolated from the above strain and from other fungi were tested for the inhibition of gp120-CD4 binding and the structure-activity relationship is discussed. Consequently, 5-bromoochrephilone is the strongest inhibitor (IC50, 2.5 microM). A halogen atom at C-5, a proton at C-8 and a diene structure in C-3 side chain of 6-oxoisochromane ring are necessary for gp120-CD4 binding.

New phenanthrenes, loddigesiinols A (1) and B (7), and stilbenes, loddigesiinols C (8) and D (9), were isolated from 80% ethanol extract of Dendrobium loddigesii ROLFE (Orcharedceae) along with known compounds, including five phenanthrenes, three stilbenes, two lignans, and three sterols. Their structures were determined by spectroscopic studies. These compounds were evaluated for their inhibitory activities against nitric oxide (NO) production and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging. Phenanthrenes (1-3, 7) and dihydrophenanthrenes (4-6) showed significant inhibitory activity against NO production. In particular, 2 showed stronger inhibitory activity against NO production than 5 and 6. This suggested that this phenanthrene is a stronger inhibitor of NO production than dihydrophenanthrene. The new phenanthrenes, loddigesiinols A (1) and B (7), significantly inhibited NO production with IC(50) values of 2.6 and 10.9 muM, respectively. One new dihydrostilbene, loddigesiinol D (9), showed weak inhibitory activity against NO production with an IC(50) value of 69.7 microM, but the other new dihydrostilbene, loddigesiinol C (8), did not show this activity at 100 microM.

Novel brominated and halogen-less azaphilone (oxoisochromane) derivatives, 5-bromoochrephilone and dechloroisochromophilone IV, and known derivatives, dechloroisochromophilone III and isorotiorin, were isolated from the culture broth of a producing organism of isochromophilones I and II (azaphilones inhibiting gp120-CD4 binding), Penicillium multicolor FO-2338, fermented in a medium containing potassium bromide. Nineteen azaphilone-related compounds isolated from the above strain and from other fungi were tested for the inhibition of gp120-CD4 binding and the structure-activity relationship is discussed. Consequently, 5-bromoochrephilone is the strongest inhibitor (IC50, 2.5 microM). A halogen atom at C-5, a proton at C-8 and a diene structure in C-3 side chain of 6-oxoisochromane ring are necessary for gp120-CD4 binding.

The structure of chloropeptin I, a gp120-CD4 binding inhibitor having a potent anti-HIV activity, was elucidated by 1H and 13C NMR experiments and chemical degradation. It is a peptide antibiotic consisting of six aryl amino acids residues and an alpha-oxo aryl acid some of which have chlorine atoms.

Several isochromophilone analogues were synthesized from sclerotiorin (1) by Wittig reactions and aldol condensation reaction. The structures of the products were elucidated from MS, elemental analysis, 1H NMR and 13C NMR spectra, and their inhibitory activities against gp!20-CD4 binding were determined.

Streptomyces avermitilis produces the anthelmintic and insecticidal secondary metabolite avermectins. Following mutagenesis of a recombinant strain, S. avermitilis K2038 (aveD X) with N-methyl-N'-nitro-N-nitrosoguanidine, a derivative strain K2057 (aveD aveE X), was isolated, which produced seven avermectin-related compounds different from the eight components of avermectins. Four among these seven compounds from mutant K2057 were found to be new metabolites. Their structures were 4'-deoleandrosyl-6,8a-seco-6,8a-deoxyavermectin B1a, 4'-deoleandrosyl-6,8a-seco-6,8a-deoxy-5-oxoavermectin B1a, 4'-deoleandrosyl-6,8a-seco-6,8a-deoxy-5-oxoavermectin B2a and 6,8a-seco-6,8a-deoxy-2,5-didehydroavermectin B2a, all of which lack the furan ring at C-6, C-8a. The mutation affecting the formation of the furan ring (aveE) is located in the center of the gene cluster for avermectin biosynthesis.

Seven flavonoid glucuronides (1-7) were isolated from "Bo Ye Hang Chin" ( ?? ?? ?? ?? ), the whole herb of (Scutellaria)___- (ikonnikovii)___- Juz. (Labiatae). A new glucuronyl flavone named ikonnikoside I (1) was formulated as 5, 6, 2'-trihydroxy-7-O-glucuronyl flavone. Other compounds (2-7) were identified as norwogonin-8-O-glucuronide (2), scutellarin (3), 5, 2'-dihydroxy-7-O-glucuronylflavone (4), baicalin (5), norwogonin-7-O-glucuronide (6) and chrysin-7-O-glucuronide (7).