Kombic acid,a hydroquinone polyisoprenoic carboxylic acid from Pycnanthus kombo seed fat

The fat of the seeds from the West African tree Pycnanthus kombo contains ca 20% of a hitherto undescribed compound. This compound was identified as 16(2′,5′-dihydroxy-3′-methylphenyl)-2,6,10,14-tetramethyl-2,6,10,14-hexadecatetraenoic acid, for which the name kombic acid is proposed.     

Peucelinendiol,a new acyclic diterpenoid from Peucedanum oreoselinum

A new diterpenoid has been isolated from roots of Peucedanum oreoselinum. Mainly by spectroscopic methods, its structure is shown to be (+)-(E)-7-hydroxymethyl-2,6,10,14-tetramethyl-2,9,13-pentadecatrien-6-ol, yet without specification of stereochemistry at C-6 and C-7. Furthermore the roots afforded a high yield of falcarindiol, (+)-(Z)-heptadeca-1,9-dien-4,6-diyn-3,8-diol.     

Microwave assisted one-pot synthesis of highly potent novel isoniazid analogues

A series of novel isoniazid (INH) analogues were synthesized by microwave assisted one pot reaction of INH, various benzaldehydes and dimedone in water with catalytic amount of DBSA. The synthesized compounds were evaluated for their anti-TB activity against Mycobacterium tuberculosis H37Rv (MTB) and multi-drug resistant Mycobacterium tuberculosis (MDR-TB). Among the 29 compounds, compound N-[9-[2-(benzyloxy)phenyl]-3,3,6,6-tetramethyl-1,8-dioxo-2,3,4,5,6,7,8,9-octahydro-10(1H)-acridinyl]isonicotinamide (12) inhibited MTB with MIC of <0.17 μM and MDR-TB with MIC of 0.69 μM.     

Synthesis of α- and β-glycosides containing spin labels,as probes for studies of carbohydrate-protein interaction

Nitroxide spin-labeled α-d-glycopyranosides were synthesized in good yield and in a highly stereoselective manner by reaction of per-O-benzyl-α-d-glycopyranosyl bromides with 2,2,6,6-tetramethyl-4-piperidinol under the bromide ion-catalyzed conditions devised by Lemieux etal. After hydrogenolysis, the deblocked intermidiates were oxidized to give the desired, spin-labeled α-d-glycopyranosides. Nitroxide spin-labeled α-d-glycopyranosides, as well as a β-maltoside, were synthesized by standard methods. The synthesis is also described of 2-amino-2-deoxy-d-glucose and -d-galactose derivatives having a spin label at C-2, and of the spin-labeled compound 1-[4-(β-d-galactopyranosyloxy)phenyl]-3-(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl)-2-thiourea.     

Microbial Oxidation of Isoprenoid Alkanes,Phytane, Norpristane and Farnesane

Rhodococcus sp. BPM 1613, a pristane oxidizing microorganism, grows on isoprenoid hydrocarbons such as phytane (2,6,10,14-tetramethylhexadecane), norpristane (2,6,10-trimethylpentadecane) and farnesane (2,6,10-trimethyldodecane) as the sole carbon source, resulting in accumulation of oxidation products in the culture broth. The oxidation products of phytane, norpristane and farnesane in the respective culture broth were isolated and purified by the use of silica gel column chromatography. Their chemical structures were determined by instrumental analyses such as IR, NMR and mass spectrometry. The oxidation products of phytane were identified as 2,6,10,14-tetramethyl-1-hexadecanol and 2,6,10,14-tetramethylhexadecanoic acid, the product of norpristane as 2,6,10-trimethyl-1-pentadecanol, and that of farnesane as 2,6,10-trimethyl-1-dodecanol. All these oxidation products were either monoalcohols or monocarboxylic acids derived through oxidation of the isopropyl terminus of each alkane.

In addition, the relationship between the terminal structure of isoprenoid hydrocarbons and microbial oxidation was explored on the basis of these results.     

Antiparasitic activity of prenylated benzoic acid derivatives from Piper species

Fractionation of dichloromethane extracts from the leaves of Piper heterophyllum and P. aduncum afforded three prenylated hydroxybenzoic acids, 3-[(2E,6E,10E)-11-carboxy-3,7,15-trimethyl-2,6,10,14-hexadecatetraenyl)-4,5-dihydroxybenzoic acid, 3-[(2E,6E,10E)-11-carboxy-13-hydroxy-3,7,15-trimethyl-2,6,10,14-hexadecatetraenyl]-4,5-dihydroxybenzoic acid and 3-[(2E,6E,10E)-11-carboxy-14-hydroxy-3,7,15-trimethyl-2,6,10,15-hexadecatetraenyl]-4,5-dihydroxybenzoic acid, along with the known compounds, 4,5-dihydroxy-3-(E,E,E-11-formyl-3,7,15-trimethyl-hexadeca-2,6,10,14-tetraenyl)benzoic acid (arieianal), 3,4-dihydroxy-5-(E,E,E-3,7,11,15-tetramethyl-hexadeca-2,6,10,14-tetraenyl)benzoic acid, 4-hydroxy-3-(E,E,E-3,7,11,15-tetramethyl-hexadeca-2,6,10,14-tetraenyl)benzoic acid, 3-(3,7-dimethyl-2,6-octadienyl)-4-methoxy-benzoic acid, 4-hydroxy-3-(3,7-dimethyl-2,6-octadienyl)benzoic acid and 4-hydroxy-3-(3-methyl-1-oxo-2-butenyl)-5-(3-methyl-2-butenyl)benzoic acid. Their structures were elucidated on the basis of spectroscopic data, including homo- and heteronuclear correlation NMR experiments (COSY, HSQC and HMBC) and comparison with data reported in the literature. Riguera ester reactions and optical rotation measurements established the compounds as racemates. The antiparasitic activity of the compounds were tested against three strains of Leishmania spp., Trypanosoma cruzi and Plasmodium falciparum. The results showed that 3-(3,7-dimethyl-2,6-octadienyl)-4-methoxy-benzoic acid exhibited potent and selective activity against L. braziliensis (IC₅₀ 6.5 μg/ml), higher that pentamidine used as control. Moreover, 3-[(2E,6E,10E)-11-carboxy-3,7,15-trimethyl- 2,6,10,14-hexadecatetraenyl)-4,5-dihydroxybenzoic acid and 4-hydroxy-3-(3-methyl-1-oxo-2-butenyl)-5-(3-methyl-2-butenyl)benzoic acid showed moderate antiplasmodial (IC₅₀ 3.2 μg/ml) and trypanocidal (16.5 μg/ml) activities, respectively.     

Pyrazole alkaloids from watermelon (Citrullus lanatus) seeds

Three new compounds, i.e. 1-[2-(5-hydroxymethyl-1H-pyrrole-2-carbaldehyde-1-yl)ethyl]-1H-pyrazole (1), 1-({[5-(α-d-galactopyranosyloxy)methyl]-1H-pyrrole-2-carbaldehyde-1-yl}-ethyl)-1H-pyrazole (2), and (4-hydroxyphenyl)methanol 4-[β-d-apiofuranosyl(1→2)-O-β-d-glucopyranoside] (3), were isolated from an extract of watermelon seeds. Compounds 1 and 2 were pyrazole-alkaloids with a pyrrole ring. This is the first study to show compounds with pyrrole and pyrazole rings in a molecule isolated from natural products. In the evaluation for melanogenesis inhibitory, compound 1 exhibited modest inhibitory activity on melanogenesis without cytotoxicity. Meanwhile compound 2 showed some inhibitory activity accompanied by some cytotoxicity.     

Acyclic diterpenes from Croton kerrii

Croton kerrii; Euphorbiaceae; acyclic diterpenes; anti-reserpine ulcer; (E,E,Z)-11- hydroxymethyl-3,7,15-trimethyl-2,6,10,14-hexadecatetraen-1-ol; (E,E,E)-11-formyl-3,7,15-trimethyl-2,6,10,14-hexadecatetraen-1-ol.     

An acyclic diterpene from Viguiera deltoidea

A new geranylgeraniol type diterpene, named viguieric acid, was isolated from the dichloromethane extracts of V. deltoidea. Its structure was assigned to be (2Z,6Z,10E)-3,15-dimethyl-7-carboxy-11-formyl-2,6,10,14-hexadecatetraen-1-ol.     

红豆杉一内生真菌化学成分的研究(英文)

从药用植物红豆杉 (Taxuschinensis (Pilg.)Rehd .)的内生真菌———粘帚霉属真菌 (Gliocladiumsp .,简称F菌 )菌丝体中分离到 3个化合物 ,根据光谱方法确定了它们的结构。其中 ,(2 0S ,2 2S)_4a_同_2 2_羟基_4_氧杂麦角甾_7,2 4 (2 8)_二烯_3_酮为新化合物 ,化合物 4 ,8,12 ,16_四甲基_1,5 ,9,13_四氧杂环十六烷_2 ,6 ,10 ,14_四酮为首次从该属真菌中分离到 ,6 ,9_环氧麦角甾_7,2 2_二烯_3_羟基为首次从F菌中分离到。     

Enzymic reduction of [6]-gingerol,a major pungent principle of ginger,in the cell-free preparation of rat liver

A reductive metabolism of S-(+)-[6]-gingerol [1-(4'-hydroxy-3'-methoxyphenyl)-5-hydroxydecan-3-one], the major pungent principle of ginger, was investigated in vitro with phenobarbital-induced rat liver 10,000 x g supernatant containing the NADPH-generating system. The ethyl acetate-extractable products were isolated and two metabolites were identified as diastereomers of [6]-gingerdiol by gas chromatrography/mass spectrometry. The ratio of two isomers formed in the above reaction was about 1:5, suggesting the stereospecific reduction of S-(+)-[6]-gingerol by carbonyl reductase activity present in the postmitochondrial supernatant fraction of rat liver. The enzymic reduction of S-(+)-[6]-gingerol thus introduces the second asymmetric carbon center in the molecule with concomitant production of S,S- and R,S-isomers of [6]-gingerdiol in different proportions. This stereospecific reduction of [6]-gingerol may be relevant to the clinical use of the compound.     

Dunawithanines A and B,the first withanolide glycosides from Dunalia australis

Withanolide D, 7β-acetoxy-withanolide D and two new withanolide glycosides, named dunawithanines A and B, were isolated from Dunalia australis. From physical data and chemical transformations, the structures of the new compounds were determined as (20R,22R-O(3)-[2′,3′-di-O-(β-D-glucopyranosyl)-β-D-glucopyranosyl]-3β,20-dihydroxy-1α-acetoxy-witha-5,24-dienolide and the corresponding O(3)-[β-D-glucopyranosyl(1′ → x)-β-D- glucopyranosyl] compound, representing the first withanolide glycosides found in the plant kingdom.     

Novel acyclic diterpenes from the brown alga Cystoseira crinita

Three acyclic diterpenes have been isolated from the brown alga Cystoseira crinita and characterized as (2E,10E)-1,6-dihydroxy-7-methylene-13-keto-3,11,15-trimethylhexadeca-2,10,14-triene, (2E,5E,10E)-1,7-dihydroxy-13-keto-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetracne and (2E, 1OE)-1-hydroxy-6,13-diketo-7-methylene-3,11,15-trimethylhexadeca-2,10,14-triene.     

3,4,8,9,10-Pentahydroxy-dibenzo[b,d]pyran-6-one from Tamarix nilotica

A new natural product, 3,4,8,9,10-pentahydroxy-dibenzo-[b,d]pyran-6-one was isolated from the flowers of Tamarix nilotica which also contains the known compound ellagic acid, 2,3,7,8-tetrahydroxy [1]benzopyrano[5,4,3-cde][1]benzopyran-5,10-dione. The structure of the new compound was determined by chemical and spectroscopic methods. The ¹³C MNR spectrum of ellagic acid was recorded and assigned.     

Helianthol a,a sesquiterpene alcohol from Helianthus tuberosus

A new sesquiterpene alcohol, helianthol A, was isolated from the aerial parts of Helianthus tuberosus. The structure of this compound has been established as (+)-2-methyl-6-[4-methyl-3′-cyclohexen-1′-(R)-yl]-3,6-heptadien-2-ol by chemical and spectroscopic methods.     

Dicorynamine and harmalan-N-oxide,two new β-carboline alkaloids from Dicorynia guianensis Amsh heartwood

The chemical investigations of Dicorynia guianensis heartwood led to the isolation of four new indole alkaloids for the first time in this plant. Compound (1) identified as spiroindolone 2′,3′,4′,9′-tetrahydrospiro [indoline-3,1′pyrido[3,4-b]-indol]-2-one, and compound (3) described as nitrone 1-methyl-4,9-dihydro-3H-pyrido [3,4-b] indole 2-oxide and were isolated for the first time as natural products. ABTS antioxidant activity guided their isolation.     

3-[2-Amino-2-imidazolin-4(5)-yl]alanine (enduracididine) and 2-[2-amino-2-imidazolin-4(5)-yl] acetic acid in seeds of Lonchocarpus sericeus

3-[2-Amino-2-imidazolin-4(5)-yl]alanine (enduracididine) and 2-[2-amino-2-imidazolin-4(5)-yl] acetic acid have been isolated from seeds of Lonchocarpus sericeus. The concentration of each compound was ca 0.5 % of the fresh seed weight.     

Formation of (-⊃-1′,2′-epi-2-cis-xanthoxin acid from a precursor of abscisic acid

Tomato shoots and avocado mesocarp supplied with (±)-[2-¹⁴C]-5-(1,2-epoxy-2,6,6-trimethylcyclohexyl)-3-methylpenta-cis-2-trans-4-dienoic acid metabolize it into (+)-abscisic acid and a more polar material that was isolated and identified as (?)-epi-1′(R),2′(R)-4′(S)-2-cis-xanthoxin acid. The (+)-1′(S),2′(S)-4′(S)-2-cis-xanthoxin acid recently synthesized from natural violaxanthin, has the 1′,2′-epoxy group on the opposite side of the ring to that of the 4′(S)-hydroxyl group and the compound is rapidly converted into (+)-abscisic acid. The 1′,2′-epoxy group of (?)-1′,2′-epi-2-cis-xanthoxin acid is on the same side of the ring as the 4′(S) hydroxyl group: the compound is not metabolized into abscisic acid. The configuration of the 1′,2′-epoxy group probably controls whether or not the 4′(S) hydroxyl group can be oxidized. (+)-2-cis-Xanthoxin acid is probably not a naturally occurring intermediate because a ‘cold trap’, added to avocado fruit forming [¹⁴C]-labelled abscisic acid from [2-¹⁴C]mevalonate, failed to retain [¹⁴C] label.     

Production of 20-carboxy-pregna-1,4-dien-3-one from sterols by mutants of Rhodococcus sp

By selection of microorganisms which preferentially attack the side-chain of either cholesterol or β-sitosterol (campesterol) we isolated five mutants of Rhodococcus sp. strain k-3 was obtained from the wild-type strain MIL 1037 and μ-9, μ-11, and μ-12 from MIL 1038, by mutagenic treatment and produced preferentially 20-carboxy-pregna-1,4-dien-e-one from β-sitosterol (campesterol) or cholesterol in good yield. The other mutant, μ-7, isolated from the wild-type strain MIL 1038 produced a new compound identified as 7aβ-methyl-1β-[1′,5′-dimethyl-6′-hydroxy-hexyl]-5-oxo-3aα-hexahydro-4-indanpropionic acid from cholesterol. A temporary accumulation of this compound was observed during the transformation of cholesterol. This compound could be used as an intermediate for the chemical synthesis of steroids with unnatural configurations.     

N-Halamine-coated cotton for antimicrobial and detoxification applications

A new N-halamine precursor, 3-(2,3-dihydroxypropyl)-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione (TTDD diol), was synthesized and bonded onto cotton fabrics. Fabrics with variable amounts of chlorine loading were prepared by using several concentrations of TTDD diol. A second N-halamine precursor, 3-(3-triethoxysilylpropyl)-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione (TTDD siloxane), was also synthesized and bound to cotton for comparison purposes. The coated cotton fabrics contained two types of N–Cl moieties after chlorination of the amine and amide groups. Swatches with variable chlorine loadings were challenged with Staphylococcus aureus and Escherichia coli O157:H7 as a function of contact time. The biocidal test results showed that the chlorine loadings and surface hydrophobicities influenced the antimicrobial efficacies. The chlorinated swatches have also been employed to oxidize the simulant of chemical mustard to the less toxic sulfoxide derivative.