Pentacyclic triterpenoids from Embelia schimperi

Five oleanane-type pentacyclic triterpenoids were isolated by chromatographic separation of a chloroform extract of the stem bark of Embelia schimperi. Three of these compounds have a methyleneoxy bridge. Two compounds, embelinone and schimperinone, are reported here for the first time from a natural source (they have been synthesized previously during chemical transformations). Their structures were determined by spectroscopic techniques, among which 2-D NMR was useful for complete characterization. Three of the triterpenoids exhibited mild antibacterial properties against the gram-positive bacterial strain Rhodococcus sp.     

Two new pentacyclic triterpenoids from the stems of Manihot esculenta

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Pentacyclic triterpenoid and saponins from Gambeya boukokoensis

Chemical studies of the EtOAc extract of Gambeya boukokoensis Aubr. et Pellegr. stem bark led to the isolation of eight compounds. Three of them were elucidated as new compounds and designated as: gamboukokoensein A, 1alpha,2alpha,3beta,19alpha,23-pentahydroxyurs-12-en-28-oic acid; gamboukokoenside A, 2beta,3beta,6beta,28-tetrahydroxyolean-12-en-23-oic acid 23-O-alpha-L-arabinopyranosyl ester and gamboukokoenside B, 6beta,28-dihydroxy-3-oxoolean-12-en-23-oic acid 23-O-alpha-L-arabinopyranosyl ester. The other five compounds were known and identified as myrianthic acid, protobassic acid, oleanolic acid, erythrodiol and chondrillasterol. Their structures were elucidated on the basis of one and two dimensional NMR spectroscopic techniques, FABMS, ESMS and chemical evidence.     

Two triterpenoids and other constituents from Petasites tricholobus

Two migrated ursane skeleton triterpenoids, one is D:B-friedoursane-3alpha,16alpha-dihydroxy-7alpha,8alpha-epoxy-5(10)-ene, named petatrichol A (1) and the other one represents a novel triterpenoid carbon framework, named petatrichol B (2), along with 10 known compounds were isolated from the rhizome of Petasites tricholobus. Their structures were elucidated on the basis of spectroscopic methods (IR, EIMS, HRMS, 1D and 2D NMR). The triterpenoids were assayed against Escherichia coli, Staphylococcus aureus and Bacillus subtilis. Compounds 1 and 2 exhibited significant antibacterial activity against B. subtilis.     

Pentacyclic triterpenoids from the aerial parts of Lantana camara and their nematicidal activity

Two new olean-12-ene triterpenoids, camarolic acid (1) and lantrigloylic acid (2), have been isolated from the aerial parts of Lantana camara, along with ten known triterpenes, namely, camaric acid, lantanolic acid, lantanilic acid, pomolic acid, camarinic acid, lantoic acid, camarin, lantacin, camarinin, and ursolic acid. The new compounds have been characterized as 3,25-epoxy-3alpha-hydroxy-22beta-{[(S)-3-hydroxy-2-methylidenebutanoyl]oxy}olean-12-en-28-oic acid (1) and 3,25-epoxy-3alpha-hydroxy-22beta-[(3-methylbut-2-enoyl)oxy]olea-9(11),12-dien-28-oic acid (2) through spectroscopic studies and a chemical transformation. Seven of the constituents, namely pomolic acid, lantanolic acid, lantoic acid, camarin, lantacin, camarinin, and ursolic acid, were tested for nematicidal activity against root-knot nematode Meloidogyne incognita. Pomolic acid, lantanolic acid, and lantoic acid showed 100% mortality at 1 mg/ml concentration after 24 h, while camarin, lantacin, camarinin, and ursolic acid exhibited 100% mortality at this concentration after 48 h. These results are comparable to those obtained with the conventional nematicide furadan (100% mortality at 1 mg/ml concentration after 24 h).     

Pyranones from kiwi-associated fungus Fusarium tricinctum and their antibacterial activity

Four new pyrone derivatives, fusaritricins A–D (1−4), together with five known analogues, were obtained from the kiwi endophytic fungus Fusarium tricinctum. Their structures were established by extensive spectroscopic data analysis and their absolute configurations were determined by quantum chemical calculations. Compounds 1, 2, 3, and 9 exhibited antibacterial activity against plant pathogen Pseudomonas syringae pv. Actinidiae (Psa) with MIC values of 128, 128, 64, and 64 µg/mL, respectively. This is the first report of anti-Psa activity of pyrone derivatives.     

Ring A-seco triterpenoids with antibacterial activity from Dysoxylum hainanense

Five new ring A-seco triterpenoids, dysoxyhainic acids F-J (1-5), along with a known ring A-seco triterpenoid koetjapic acid (6) were isolated from the twigs and leaves of Dysoxylum hainanense. Their structures were established on the basis of extensive spectroscopic analysis. Antimicrobial activity of all the compounds against fungi and bacteria were tested. Compounds 2-4 and 6 exhibited significant antimicrobial activity against Gram-positive bacteria, and the antibacterial SAR (structure-activity relationship) was also briefly discussed.     

Pentacyclic triterpenoids and sterols from seven species of mangrove

The isolation of pentacyclic triterpenoids from seven species of fresh mangrove leaves using a simple and rapid method is described. The leaves were homogenized using chloroform—methanol and the extract was diluted with water to precipitate out triterpenoids which were separated into neutral and acidic fractions. These were analysed by gas-liquid chromatography as acetyl and trimethylsilyl ether derivatives on a 3% OV-17 column. Sterols were isolated from the chloroform layer by preparative thin layer chromatography and were analysed by gas-liquid chromatography as their trimethylsilyl ether derivatives on a 3% OV-17 column. The triterpenoids found were α-amyrin, β-amyrin, lupeol, oleanolic acid and ursolic acid in most of the samples. Sterols found in all the samples were cholesterol, campesterol, stigmasterol, sitosterol and stigmast-7-en-3β-ol. Retention indices of the triterpenoids and sterols have been determined.     

Two new alkaloids from Pachysandra terminalis and their antibacterial activity assessment

Phytochemical investigation of a 90 % ethanol extract of Pachysandra terminalis Sieb. Et Zucc led to the isolation of a novel alkaloid, terminamine T (1); a new pregnane-type alkaloid, terminamine U (2); and four known pregnane-type alkaloids (3-6). The structures of these compounds were elucidated on the basis of nuclear magnetic resonance spectra, mass spectrometry data, single-crystal X-ray diffraction, and by a comparison with data from the literature. All compounds were evaluated for their antibacterial activities against gram-positive (S. aureus, ATCC 29213) and gram-negative (E. coli, ATCC 25922) bacteria. Compounds 2-6 exhibited generally modest to poor antibiotic properties. Furthermore, compound 2 showed antibacterial activity against methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-resistant Staphylococcus aureus (MRSA), and methicillin-resistant Staphylococcus aureus USA300 (LAC) with a minimal inhibitory concentration (MIC) value of 32 μg/mL (75 μM) and minimum bactericidal concentration (MBC) values of 64, 128, and 128 μg/mL (150, 300, and 300 μM), respectively.     

Cucurbitane-type triterpenoids from the branches and leaves of Elaeocarpus sylvestris

The chemical structures of nine cucurbitane-type triterpenoids from the branches and leaves of Elaeocarpus sylvestris (Elaeocarpaceae), including undescribed 29-hydroxymogroside I E₂, epimogroside I E₂, epimogroside I E₁, 24-oxomogroside I E₁, and 11-O-acetylmogroside I E₁, were determined using mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. The absolute configuration of 29-hydroxymogroside I E₂ was confirmed by performing an X-ray diffraction analysis. Cucurbitacin D and 11-O-acetylmogroside I E₁ showed cytotoxicity toward human leukemia HL-60, human lung adenocarcinoma A549, human hepatoma SMMC-7721, human breast cancer MCF-7, and human colon cancer SW480 cell lines. The presence of a 11-O-acetyl group might increase the cytotoxicity of this type of triterpenoids.     

紫芝酸性三萜类化合物体外抑癌和抑菌作用的研究

采用噻唑蓝比色(MTT)法研究紫芝酸性三萜对几种癌细胞体外增殖的影响,并用管碟法检测了紫芝胞内酸性三萜对几种细菌和霉菌的体外抑菌作用。结果表明,紫芝胞内酸性三萜和胞外酸性三萜在250μg/mL时,对人肝癌细胞BEL7402和人乳腺癌细胞MCF-7均有显著抑制作用(P<0.05),但对人胃癌细胞SGC-7901没有显著抑制作用(P>0.05)。BEL7402细胞的生长曲线试验表明,胞内酸性三萜组的细胞受到显著抑制,未出现指数增长期,且BEL7402细胞培养3d后,对照组细胞数目多、均匀,而胞内酸性三萜组的细胞数目明显减少,且细胞变小。抑菌试验结果表明,胞内酸性三萜在40mg/mL时,对大肠杆菌Escherichia coli和金黄色葡萄球菌Staphylococcus aureus的生长均具有显著抑制作用(P<0.01),对枯草芽孢杆菌Bacillus subtitis和青霉的Penicillium chrysogenum抑制作用较弱;而在此浓度下对黑曲霉Aspergillus niger没有抑制作用。该样品对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌、黑曲霉和青霉的MIC分别为20mg/mL、20mg/mL、40mg/mL、80mg/mL和40mg/mL。此外,该酸性三萜的抑菌成分在60℃下(处理2h)较稳定,但在80℃以上,热稳定性较差,活性降低。     

Chemical composition and antibacterial activity of the essential oil of Drimys granadensis L.f. leaves from Colombia

Drimys granadensis L.f., a native plant from Colombia, has been included in the Vademecum de Plantas Medicinales de Colombia by the Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, due to its widespread use in the folk medicine for the treatment of gastrointestinal ailments. The chemical composition of the essential oil of Drimys granadensis obtained by hydrodistillation of the leaves was analyzed by GC and GC/MS analyses. A total of 85 components were identified, with the major compounds germacrene D (1, 14.7%), sclarene (9.5%), a-cadinol (7.3%), longiborneol acetate (2, 6.3%), drimenol (4.2%), (Z)-β-ocimene (3, 4.2%), a-pinene (4, 3.2%), and β-elemene (5, 2.7%). The essential oil was also tested against eight bacteria using the Kirby-Bauer disk-diffusion method. Most of the Gram-positive bacteria tested were susceptible to the D. granadensis essential oil, while the Gram-negative bacteria tested were not.     

Antibacterial and antioxidant activities of compounds isolated from the leaves of Symphonia globulifera (Clusiaceae) and their chemophenetic significance

The phytochemical study was done on the methanol extract from of the leaves of Symphonia globulifera. This plant has been used in traditional medicine to treat of different ailments such as malaria, diseases of the skin, diabetes, cough, intestinal worms, pre-hepatic jaundice and fever. Chromatographic fractionation and purification of this extract led to the isolation and characterization of twelve compounds (1–12) including pristriol (1), robustaflavone (2), polycarpol (3), 7''-O-methylrobustaflavone (4), amentoflavone (5), stigmasterol glucoside (6), epicatechin (7), apigenin (8), luteolin (9), 1,5-dihydroxyxanthone (10), β-sitosterol 3-β-D-glucopyranoside (11) and a mixture of stigmasterol and β-sitosterol (12). The structures of compounds 1–12 were elucidated on the basis of 1D and 2D NMR, mass spectrometric and the spectroscopic data as well as comparison with the literature. All these compounds were isolated for the first time from Symphonia genus. The NMR spectra and structure elucidation of compound 1 were reported for the first in the literature. The antibacterial and antioxidant activities of three of these compounds were evaluated. The chemophenetic significance of these compounds is also discussed.     

Two new cycloartane-type triterpenoids and one new flavanone from the leaves of Dasymaschalon dasymaschalum and their biological activity

Two new cycloartane-type triterpenoids, 3β-hydroxy-21-O-acetyl-24-methylenecycloartane (3) and 3β,21-dihydroxy-24,31-epoxy-24-methylenecycloartane (4), one new flavanone, 7-hydroxy-6,8-dimethoxyflavanone (5), two new natural products, 2-hydroxybenzyl benzoate (7) and 2-phenyl-2-acetoxyethyl benzoate (8), and ten known compounds, 3β-hydroxy-24-methylenecycloartane (1), 3β,21-dihydroxy-24-methylenecycloartane (2), desmosdumotin B (6), artabotrene (9), (?)-senepoxide (10), (+)-crotepoxide (11), (?)-1,6-desoxypipoxide (12), rotundol (13), cassipourol (14) and (+)-spathulenol (15) were isolated from the leaves of Dasymaschalon dasymaschalum. The structures of the new compounds were elucidated by spectroscopic analysis and of the known compounds by comparison of their physical, UV, IR, ¹H and ¹³C NMR data with those of published compounds. Antimycobacterial, antiplasmodial and cytotoxic activities of the isolates, except 8 and 10 were evaluated. Compounds 1, 4, 5, 11, 12 and 15 exhibited potent cytotoxic activities against human lung cancer cell lines (NCI-H187) with respective IC₅₀ values of 4.67, 7.82, 1.85, 6.33, 3.07 and 6.68 μg/mL.     

Three new constituents from the roots of Erythrina variegata and their antibacterial activity against methicillin-resistant Staphylococcus aureus

Two new isoflavonoids, eryvarins V and W (1 and 2, resp.), and a new chromen-4-one derivative, eryvarin X (3), along with three known isoflavonoids, 4-6, were isolated from the roots of Erythrina variegata. Their structures were established by spectroscopic analyses. Compound 1 is a rare naturally occurring isoflavanone which possesses a OH group at C(3). Among the new compounds 1-3, 2 exhibited a potent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) strains.     

Antimicrobial activity of pentacyclic triterpenes isolated from African Combretaceae

Four pentacyclic tritepenes were isolated from Combretum imberbe Engl. & Diels, of which two are novel glycosidic derivatives of 1alpha,3beta,23-trihydroxyolean-12-en-29-oic acid (hydroxyimberbic acid). Terminalia stuhlmannii Engl. & Diels stem bark yielded two glycosides of hydroxyimberbic acid, one of which is reported for the first time. The structures of the isolated compounds were elucidated by spectroscopic methods. Several of the compounds had antibacterial activity, imberbic acid showing particularly potent activity against Mycobacterium fortuitum and Staphylococcus aureus.     

An antibacterial cytochalasin derivative from the marine-derived fungus Diaporthaceae sp. PSU-SP2/4

A new pentacyclic cytochalasin (diaporthalasin, 1) and a new ethyl trihydroxytridecatrienoate (diaporthacol, 2) together with five known compounds, R-mevalonolactone (4), dothiorelone C (5), (4S,7S,13S)-4,7-dihydroxy-1,3-tetradeca-1,5-dienolide (6), 4β-acetoxy-9β,10β,15α-trihydroxyprobotrydial (7) and O-methyldihydrobotrydial (8) were isolated from the marine-derived fungus Diaporthaceae sp. PSU-SP2/4. The structures were established by spectroscopic techniques. Compound 1 displayed significant antibacterial activity against both Staphylococcus aureus and methicillin-resistant S. aureus with equal MIC values of 2 μg/mL.     

Synthesis and antiviral activity of lupane triterpenoids with modified cycle E

A reductive transformation of the peroxide products of ozonolysis of derivatives of 3β-O-acetyl-22(17→28)-abeo-lupa-17(28),20(29)-diene and the subsequent intramolecular ketalization led to a compound with a trioxane fragment. This is a new approach to a skeletal modification of triterpenoid cycle E. An activity of the synthesized compounds was found toward the viruses of type A influenza and herpes simplex.     

南极抗细菌活性菌株的筛选及系统发育分析

分别以大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌、青枯假单胞菌、绿脓假单胞菌和苏云金芽孢杆菌为指示菌,采用琼脂扩散法对实验室保存的580株极地细菌进行了抗菌活性菌株的筛选与活性验证,从中筛选出4株对上述指示菌株具有明显抗菌效果的活性菌株,其编号分别为97、Z11、Z18及Z19,并对其生长曲线、抗菌活性曲线和系统发育地位进行研究。结果表明,4株菌均在培养24 h后进入指数生长期,菌株97在培养48 h后达到稳定期,而菌株Z11、Z18及Z19在培养60 h后达到稳定期。抗菌活性分别在培养84、96、72和72 h时达到最高。系统发育分析表明,该4株菌分别属于伦黑墨氏菌属(Rheinheimera)、嗜冷杆菌属(Psychrobacter)、假单胞菌属(Pseudomonas)和嗜冷杆菌属(Psychrobacter)。