A new 1,5-seco grayanotoxin from Rhododendron decorum

A new minor 1,5-seco-5-oxo-grayanotoxin named grayanotoxin XXI (1), together with three known grayanotoxins, grayanotoxins I, IV and VIII, has been isolated from the leaves of Rhododendron decorum (Ericaceae). The structure of the new compound (1) was determined on the basis of spectroscopic data.     

Chemical constituents from Dendrobium hainanense

A new phenolic derivative (1) and a new dihydrophenanthrene (2) were isolated from the aerial part of Dendrobium hainanense rofe, along with 12 known compounds. The structures of the new compounds were elucidated by spectroscopic analysis，and the relative configuration of compound 1 was determined by J-based configuration analysis (JBCA) method. Bioassay result indicated that compound 1 exhibited weak antibacterial activity against Canidia albicans and Ralstonia solanaceanum.     

Abscisic acid-type sesquiterpenes and ansamycins from Amycolatopsis alba DSM 44262

Two new abscisic acid-type sesquiterpenes (1, 2), and one new ansamycin (3), together with four known ansamycins, namely ansacarbamitocins 4–7, were isolated from the fermentation extract of Amycolatopsis alba DSM 44262. The structures of the new compounds were elucidated to be (E)-3-methyl-5-(2,6,6-trimethyl-3-oxocyclohex-1-enyl)pent-2-enoic acid (1) and (E)-3-methyl-5-(2,6,6-trimethyl-4-oxocyclohex-2-enyl)pent-2-enoic acid (2), and 9-O-methylansacarbamitocin A1 (3), on the basis of comprehensive analysis of spectroscopic data, respectively. The antimicrobial activities were also evaluated for all seven compounds.     

Iridoid glucoside, (3<Emphasis Type="Italic">R</Emphasis>)-oct-1-en-3-ol glycosides,and phenylethanoid from the aerial parts of <Emphasis Type="Italic">Caryopteris incana</Emphasis>

Eleven compounds of interest were isolated from the aerial parts of Caryopteris incana, specifically a new acyl derivative (3) of 8-O-acetylharpagide, two new (3R)-oct-1-en-3-ol glycosides (5, 6), and 6-O-caffeoylphlinoside A (11) along with seven known compounds, 8-O-acetylharpagide (1), 6′-O-p-coumaroyl-8-O-acetylharpagide (2), (3R)-oct-1-en-3-ol (matsutake alcohol) O-α-l-arabinopyranosyl-(1″ → 6′)-O-β-d-glucopyranoside (4), apigenin 7-O-neohesperidinoside (7), 6′-O-caffeoylarbutin (8), and two phenylethanoids, leucosceptoside A (9) and phlinoside A (10). This paper deals with structural elucidation of the new compounds.     

Four new compounds from the rhizome of Aristolochia championii

Three new flavonoid glycosides (1–3) and one new aristololactam N-glycoside (4) were isolated from the rhizome of Aristolochia championii. The structures of compounds 1–4 were elucidated on the basis of their spectroscopic data and chemical evidence (UV, IR, HR-ESI-MS, 1D and 2D NMR). Their structures were determined as 8-(5-formyl-2-furanmethyl)-isorhamentin 3-O-robinobioside (1), 8-(5-methyl-2-furanoyl)-isorhamentin 3-O-robinobioside (2), 8-formylisorhamentin 3-O-robinobioside (3), and N-β-D-glucopyranosylaristololactam V (4), respectively.     

A new <Emphasis Type="Italic">Erythrina</Emphasis> alkaloid from <Emphasis Type="Italic">Erythrina herbacea</Emphasis>

A new Erythrina alkaloid, 10-hydroxy-11-oxoerysotrine (1), has been isolated from the flowers of Erythrina herbacea together with five known compounds: erytharbine (2), 10,11-dioxoerysotrine (3), erythrartine (4), erysotramidine (5) and erysotrine-N-oxide (6). The structure of the new compound was elucidated on the basis of its spectral data, including 2-D NMR and mass (MS) spectra. The new compound is a rare C-10 oxygenated Erythrina alkaloid. The antioxidant activities of the isolated compounds 1–6 were evaluated by scavenging with peroxynitrite.     

Phenolic compounds from the twigs and leaves of Tara (Caesalpinia spinosa)

Two new homoisoflavans, 4′-hydroxy-7-methoxy-3-benzyl-2H-chromene (1) and 3,4-cis-di-O-3-hydroxy-7-methoxy-3-(4-hydroxybenzyl)-4-ethoxychroman (2), one new coumarin, 7-methoxy-3-(4-hydroxybenzyl)coumarin (4), together with seven known phenolic compounds, bonducellin (3), anemarcoumarin A (5), (+)-syringaresinol (6), curuilignan D (7), scopoletin (8), and p-hydroxybenzaldehyde (9), were isolated from Tara (Caesalpinia spinosa Kuntze). The structures of the new compounds were characterized from their 1D and 2D NMR spectral data. All the compounds were isolated from this plant for the first time.     

Ceramides and cerebrosides from the marine bryozoan Bugula neritina inhabiting South China Sea

From the marine bryozoan Bugula neritina inhabiting South China Sea, a new ceramide named (2S,3R,4E)-2-(14′-methyl-pentadecanoylamino)-4-octadecene-l,3-diol (1) and a new cerebroside named 1-O-(β-d-glucopyranosyl)-(2S,3R,4E)-2-(heptadecanoylamino)-4-octadecene-l,3-diol (6), together with one known ceramide (2) and three known cerebrosides (3, 4, and 5), were isolated. Their structures were deduced by extensive spectral analysis and chemical evidences. Compound 1 is branched with a methyl [–CH(CH₃)₂] in the fatty acid moiety, which is a rare structural feature among ceramides. Compound 6 is a new cerebroside with 17 carbons in the fatty acid moiety, while 5 is a new natural product which was isolated from a natural origin for the first time.     

Two novel dammarane-type compounds from the leaves and stems of Panax quinquefolium L.

Two new dammarane-type compounds were isolated from the leaves and stems of Panax quinquefolium L. The new compounds were named as pseudo-ginsenoside RT₆ (1) and pseudoginsengenin R₁ (2). The structures of the new compounds were elucidated by the combined analysis of NMR and HR-ESI-MS as (20S,24R)-6-O-β-d-glucopyranosyl-dammar-3-one-20,24-epoxy-6α,12β,25-triol (1) and (20S,24R)-dammar-3-one-20,24-epoxy-6α,12β,25-triol (2).     

A new diarylheptanoid from the bark of Alnus japonica

A new diarylheptanoid, epihirsutanonol (1), was isolated from the bark of Alnus japonica, along with two known ones (2 and 3). Their structures were elucidated on the basis of extensive spectroscopic evidence. The new compound 1 showed significant hepatoprotective activity on the basis of t-butylhydroperoxide-induced hepatocyte injury in vitro assay.     

A bisamide and four diketopiperazines from a marine-derived Streptomyces sp.

A new bisamide N ₁-acetyl-N ₇-phenylacetyl cadaverine (1) and a series of diketopiperazines including a new diketopiperazine cyclo(2-hydroxy-Pro-R-Leu) (2), together with a new natural product cyclo(4-hydroxy-S-Pro-S-Trp) (3) and two known leucine-based diketopiperazines cyclo(4-hydroxy-R-Pro-S-Leu) (4) and cyclo (S-Pro-R-Leu) (5), were isolated from ethyl acetate extract of a fermentation broth of a marine-derived Streptomyces sp. Their structures were elucidated by the interpretation of spectroscopic analysis. The antitumor activities of compounds 1–3 against HL-60 cell lines were tested by MTT assay.     

Three new 1-(p-hydroxybenzyl)phenanthrenes from Bletilla striata

Three new benzylphenanthrenes, named 1-(p-hydroxybenzyl)-4,7-dimethoxyphenanthrene-2-ol (1), 1-(p-hydroxybenzyl)-4,7-dimethoxyphenanthrene-2,8-diol (2), and 1-(p-hydroxybenzyl)-4,7-dimethoxyphenanthrene-2,6-diol (3), along with a known analog were isolated from tubers of Bletilla striata. The structures of these new compounds were established by means of HR-ESI-MS, 1D, and 2D NMR.     

Two new antimicrobial flavanes from dragon's blood of Dracaena cambodiana

Two new flavonoids, named cambodianins D (1) and E (2), together with two known flavanes (2S)-7,4′-dihydroxy-6,8-dimethylflavane (3) and (2S)-7,3′-dihydroxy-4′-methoxy-8-methylflavane (4), were isolated from dragon's blood of Dracaena cambodiana. The new compounds were determined by HR-ESI-MS and spectroscopic techniques (UV, IR, 1D, and 2D NMR). Compounds 1–3 exhibited antimicrobial activities.     

Antioxidant phenolic glucosides from Gentiana piasezkii

An extract of Gentiana piasezkii afforded a new arbutin derivative 6′-O-vanilloylarbutin (1) and a new flavone-C-glucoside 7-O-feruloylorientin (2), together with four known flavonoids lutonarin (3), saponarin (4), isoorient (5) and luteolin (6). Their structures were established based on spectroscopic methods including 2D NMR (COSY and gHMBC) techniques. Compounds 1, 2, 5 and 6 were evaluated for the antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay system.     

Synthesis and antiviral activity of new 4-(phenylamino)/4-[(methylpyridin-2-yl)amino]-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acids derivatives

The synthesis of new 4-(phenylamino)-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid (3a-l) derivatives and the new 4-[(methylpyridin-2-yl)amino]-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid (5a–c) derivatives was achieved with an efficient synthetic route. Ethyl 4-chloro-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (1) on fusion with appropriate substituted anilines or aminopicolines gave the required new ethyl 4-(phenylamino)-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylates (2a–l) (52–82%) or new ethyl 4-[(methylpyridin-2-yl)amino]-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylates (4a–c) (50–60%), respectively. Subsequent hydrolysis of the esters afforded the corresponding carboxylic acids (3a–l) (86–93%) and (5a–c) in high yield (80–93%). Inhibitory effects of 4-(phenylamino)/4-[(methylpyridin-2-yl)amino]-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acids. Derivatives on Herpes simplex virus type 1 (HSV-1), Mayaro virus (MAY) and vesicular stomatitis virus (VSV) were investigated. Compounds 2d, 3f, 3a, and 3c exhibited antiviral activity against HSV-1, MAY, and VSV virus with EC₅₀ values of 6.8, 2.2, 4.8, 0.52, 2.5, and 1.0. None of these compounds showed toxicity for Vero cells.     

A new cembrane-type diterpenoid from Bornean liverwort Chandonanthus hirtellus

A new compound, chandonanol (1), along with four known compounds, chandonanthone (2), iso-chandonanthone (3), anastreptene (4), and (6R,7S)-sesquiphellandrene (5), was isolated from the MeOH extract of Bornean liverwort Chandonanthus hirtellus. The structure of the new metabolite was established by analyses of the spectroscopic data (1D NMR, 2D NMR, HRESIMS, and IR). These compounds were tested for their activity against antibiotic-resistant clinical strains. Chandonanol (1) exhibited potent bactericidal activity against Staphylococcus aureus and Escherichia coli.     

Three new sulfated triterpenoids from the roots of Gypsophila pacifica

Three new sulfated triterpenoids (1–3), along with one known compound (4), were isolated from the roots of Gypsophila pacifica Kom. The structures of the new compounds were established as 3β-O-sulfate gypsogenin 28-O-β-d-glucopyranosyl ester (1), 3β-O-sulfate gypsogenin (2), and 3β-O-sulfate quillaic acid (3) on the basis of 1D, 2D NMR, and HR-ESI-MS methods.     

Four new long-chain aliphatics from the feces of Trogopterus xanthipes

Chemical investigation of Trogopterus feces has led to the isolation of four new long-chain aliphatics, including two new fatty alcohols, 8,15-nonacosanediol (1) and 6,13-nonacosanediol (2), one new fatty acid ester, dihexyl 7,7′-oxydiheptanoate (3), and one new ceramide, (2R)-2-hydroxy-N-[(2S,3S,4R,11E)-1,3,4-trihydroxydocos-11-en-2-yl]heneicosanamide (4). Their structures were elucidated by means of chemical and extensive spectroscopic analysis. Compound 3 exhibited moderate activity of antithrombin in vitro.     

Mexicanolide-type limonoids from the seeds of Swietenia macrophylla

Three new mexicanolide-type limonoids, 3-O-propionylproceranolide (1), 6-O-acetylswietenin B (2), and 6-deoxyswietemahonin A (3), together with 15 known limonoids, were isolated from the seeds of Swietenia macrophylla (Meliaceae). The structures of those new compounds were established by extensive analysis of MS, 1D, and 2D NMR spectral data.     

Two new 12-membered macrolides from the endophytic fungal strain Cladosprium colocasiae A801 of Callistemon viminalis

Two new polyketide metabolites, the 12-membered macrolides 4-hydroxy-12-methyloxacyclododecane-2,5,6-trione (1) and 12-methyloxacyclododecane-2,5,6-trione (2), were isolated from the endophytic fungal strain Cladosprium colocasiae A801 of the plant Callistemon viminalis, together with five known derivatives. Their structures were fully characterized by means of detailed spectroscopic analysis for new structures, and in comparison with published data for known compounds. The antibacterial, cytotoxic, and α-glucosidase inhibitory activities of the new compounds 1 and 2 were evaluated.