Synthesis and antimicrobial activity of N'-heteroarylidene-1-adamantylcarbohydrazides and (±)-2-(1-adamantyl)-4-acetyl-5-[5-(4-substituted phenyl-3-isoxazolyl)]-1,3,4-oxadiazolines

The reaction of adamantane-1-carbohydrazide (1) with heterocyclic aldehydes, namely 5-(4-chlorophenyl)isoxazole-3-carboxaldehyde (2a), 5-(4-methylphenyl)isoxazole-3-carboxaldehyde (2b), 5-(4-methoxyphenyl)isoxazole-3-carboxaldehyde (2c), 1H-imidazole-2-carboxaldehyde and 2-butyl-4-chloro-1H-imidazole-5-carboxaldehyde, in ethanol, yielded the corresponding N'-heteroarylidene-1-adamantylcarbohydrazides 3a, 3b, 3c, 4 and 5, respectively, in good yields. The 4-acetyl-1,3,4-oxadiazoline analogues 6a?c were prepared in 48-55% yields by heating their corresponding N'-heteroarylidene-1-adamantylcarbohydrazides 3a-c with acetic anhydride for two hours. Compounds 3a-c, 4, 5 and 6a-c were tested for in vitro activities against a panel of Gram-positive and Gram-negative bacteria and the yeast-like pathogenic fungus Candida albicans. Compounds 4 and 5 displayed potent broad-spectrum antimicrobial activity, while compounds 3a-c showed good activity against the Gram-positive bacteria.     

Thiourea Derivatives,Simple in Structure but Efficient Enzyme Inhibitors and Mercury Sensors

In this study six unsymmetrical thiourea derivatives, 1-isobutyl-3-cyclohexylthiourea (1), 1-tert-butyl-3-cyclohexylthiourea (2), 1-(3-chlorophenyl)-3-cyclohexylthiourea (3), 1-(1,1-dibutyl)-3-phenylthiourea (4), 1-(2-chlorophenyl)-3-phenylthiourea (5) and 1-(4-chlorophenyl)-3-phenylthiourea (6) were obtained in the laboratory under aerobic conditions. Compounds 3 and 4 are crystalline and their structure was determined for their single crystal. Compounds 3 is monoclinic system with space group P2₁/n while compound 4 is trigonal, space group R³:H. Compounds (1–6) were tested for their anti-cholinesterase activity against acetylcholinesterase and butyrylcholinesterase (hereafter abbreviated as, AChE and BChE, respectively). Potentials (all compounds) as sensing probes for determination of deadly toxic metal (mercury) using spectrofluorimetric technique were also investigated. Compound 3 exhibited better enzyme inhibition IC₅₀ values of 50, and 60 µg/mL against AChE and BChE with docking score of −10.01, and −8.04 kJ/mol, respectively. The compound also showed moderate sensitivity during fluorescence studies.     

New triterpenes from Barringtonia asiatica

The leaves of Barringtonia asiatica afforded two new triterpenes, germanicol caffeoyl ester (1) and camelliagenone (2). Their structures were elucidated by extensive 1D- and 2D-NMR spectroscopy. It also afforded germanicol trans-coumaroyl ester (3), germanicol cis-coumaroyl ester (4), germanicol (5), camelliagenin A (6), spinasterol, sitosterol, squalene, lutein and trilinolein. Compounds 3, spinasterol and trilinolein were isolated from the fruits, while the seeds yielded spinasterol, squalene, linoleic acid and trilinolein. Compounds 1-5 exhibited antifungal activity against Candida albicans, 1-3 and 5 showed antibacterial activity against Staphylococcus aureus, while 5 is active against Pseudomonas aeruginosa.     

A new triterpenoid saponin from Abrus precatorius Linn

A new triterpenoid saponin, 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl subprogenin D (1), together with six known triterpenoids: subprogenin D (2), abrusgenic acid (3), triptotriterpenic acid B (4), abruslactone A (5), abrusogenin (6) and abrusoside C (7) were isolated from the leaves and stems of Abrus precatorius. Their structures were elucidated on the basis of physical and NMR analysis, respectively. Compounds 5 and 6 showed moderate cytotoxicity against MCF-7, SW1990, Hela, and Du-145 cell lines. Compounds 1, 2 and 4 were isolated from this plant for the first time.     

New phenolic glycosides from the stems and leaves of Casearia multinervosa

Four phenolic glycosides (1-4), including two new ones (3 and 4), have been isolated from the stems of Casearia multinervosa and identified as arbutin (1), 4-O-E-caffeoylarbutin (2), 4-O-E-coumaroylarbutin (3) and 4-O-E-feruloylarbutin (4), respectively. In addition, the two known phenolic glycosides (1 and 2) were also isolated from the leaves. Structures were elucidated on the basis of spectroscopic evidence. Compounds 1-4 were tested for cytotoxicity against the P388 mouse lympholytic cell line by an ATP Lite-M assay method and showed mild to moderate activity.     

Cytotoxic and antimalarial prenylated xanthones from Cratoxylum cochinchinense

A new prenylated xanthone, 5-O-methylcelebixanthone (1), together with six known compounds; celebixanthone (2), 1,3,7-trihydroxy-2,4-di(3-methylbut-2-enyl)xanthone (3), cochinchinone A (4), alpha-mangostin (5), beta-mangostin (6) and cochinchinone C (7) were isolated from roots of Cratoxylum cochinchinense. Their structures were elucidated by spectroscopic methods. Compounds 2 and 4-7 showed cytotoxic activity against the human lung cancer cell line (NCI-H187) with IC(50) values ranging from 0.65 to 5.2 microg/ml. Compounds 1, 2, 6 and 7 also showed antimalarial activity against Plasmodium falciparum with IC(50) values of 3.2, 4.9, 7.2 and 2.6 microg/ml, respectively.     

Bioactive constituents of the root bark of Artocarpus rigidus subsp. rigidus

Investigation of the chemical constituents of the root bark of Artocarpus rigidus BLUME subsp. rigidus has led to the isolation of six, structurally diverse phenolic compounds. These included two new compounds with modified skeletons, the flavonoid 7-demethylartonol E (1) and the chromone artorigidusin (2), together with four known phenolic compounds, the xanthone artonol B (3), the flavonoid artonin F (4), the flavonoid cycloartobiloxanthone (5), and the xanthone artoindonesianin C (6). Compounds 1, 4, and 5 exhibited antiplasmodial activity against Plasmodium falciparum. All compounds showed antimycobacterial activity against Mycobacterium tuberculosis, with 4 being the most active compound (MIC 6.25 microg/ml). Compounds 5 and 6 were active against KB cells, whereas 2, 5, and 6 showed varying toxicity to BC cells. Compounds 1-3, 5, and 6 were active in the NCI-H187 cytotoxicity assay, with 3 being the most active compound (IC(50) 1.26 microg/ml).     

Optically active antifungal azoles. VIII. Synthesis and antifungal activity of 1-[(1R,2R)-2-(2,4-difluoro- and 2-fluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl)propyl]- 3-(4-substituted phenyl)-2(1H,3H)-imidazolones and 2-imidazolidinones

New optically active antifungal azoles, 1-[(1R,2R)-2-(2,4-difluoro- and 2-fluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl)propyl ]-3-(4- substituted phenyl)-2(1H,3H)-imidazolones (1,2) and 2-imidazolidinones (3,4), were prepared in a stereocontrolled manner from (1S)-1-[(2R)-2-(2,4- difluoro- and 2-fluorophenyl)-2-oxiranyl]ethanols (15, 16). Compounds 1-4 showed potent antifungal activity against Candida albicans in vitro and in vivo, as well as a broad antifungal spectrum for various fungi in vitro. Furthermore, the imidazolidinones, 3b--e and 4d, e, were found to exert extremely strong growth-inhibitory activity against Aspergillus fumigatus.     

Phosphodiesterase-I inhibitor quinovic acid glycosides from Bridelia ndellensis

Quinovic acid-3-O-alpha-L-rhamnopyranoside (1), quinovic acid-3-O-beta-D-fucopyranoside (2), quinovic acid-3-O-beta-D-glucopyranosyl (1 --> 4)-beta-D-fucopyranoside (3), methyl gallate (4) and ethyl gallate (5) were isolated from the ethyl acetate extract of Bridelia ndellensis barks by fractionation. Compounds 1-3 showed significant inhibitory activity against snake venom phosphodiesterase-I.     

Chemical constituents of Cichorium intybus and their inhibitory effects against urease and alpha-chymotrypsin enzymes

Phytochemical investigation of the aerial parts of Cichorium intybus L. resulted in the isolation and identification of two new natural metabolites, 2,6-di[but-3(E)-en-2-onyl]naphthalene (1), and 3,3',4,4'-tetrahydroxychalcone (2), along with nine known compounds. Their structures were determined by spectroscopic techniques including 1D and 2D NMR. The known compounds were identified as scopoletin (3), 4-hydroxyphenylacetic acid (4), 3-hydroxy-4-methoxybenzoic acid (5), 4,4'-dihydroxychalcone (6), 6,7-dihydroxycoumarine (7), 1-triacontanol (8), lupeol (9), beta-sitosterol (10), and beta-sitosterol-3-O-beta-glucopyranoside (11). Compounds 4-6 and 8 are reported for the first time from C. intybus. Compounds 2 and 3 showed weak inhibitory activities against urease and alpha-chymotrypsin enzymes, respectively.     

Plant growth inhibitory activity of azo- and azoxyformamides from Calvatia craniiformis and Lycoperdon hiemale

4-Methoxybenzene-1-ONN-azoxyformamide (1), 4-methoxybenzene-1-azoformamide (2), 4-hydroxyben-zene-1-azoformamide (3) and 4-hydroxybenzene-1-ONN-azoxyformamide (4) were isolated from the fruiting bodies of Calvatia craniiformis and Lycoperdon hiemale, respectively. Compounds 1 and 4 showed radicle growth inhibitory activities against the lettuce seedlings by more than 50% at 5.0 x 10(-1) mM, suggesting that the azoxy moiety contributes to the inhibitory activity. The plant growth inhibitory activities of 1, 2 and 4 against the barnyard millet seedlings were also measured.     

Studies on Triterpenoid Glycosides from Rhizomes of Panacis majoris and Their Antiplatelet Aggregation Activity

A new triterpenoid glycoside(1) and seven known triterpenoid glycosides, pseudoginsenoside RT2(2), yesanchinoside R2(3), vinaginsenoside R13(4), vinaginsenoside R8(5), notoginsenoside E(6), 6'-O-acetylginsenoside Re(7), 6"-O-acetylginsenoside Rb₁(8), were isolated from the rhizomes of Panacis majoris. The new triterpenoid glycoside was elucidated as 3-O-[β-D-glucopyranosyl-(1→2)-β-D-(6'-O-ethyl)-glucuronopyranosyl]-oleanolic acid-28-O-β-D-glucopyranoside by extensive spectroscopic and phytochemical methods. Compounds 2-8 were obtained from the plant for the first time. Compounds 3 and 4 displayed good activities against adenosine diphosphate (ADP)-induced platelet aggregation, and compounds 1, 5, 6 and 8 showed moderate activities. Compound 6 exhibited moderate antiplatelet aggregation activity induced by arachidonic acid(AA).     

Bioactive diterpenes from Clerodendrum kaichianum

Bioassay-guided isolation studies of the extract of Clerodendrum kaichianum Hsu., a new rearranged abietane diterpene and five known diterpene compounds were isolated by various chromatography methods. Their structures were identified by means of spectroscopic methods, including 1D- and 2D-NMR spectroscopy, as (16R)-12,16-epoxy-11,14,17-trihydroxy-17(15-->16)-abeo-8,11,13-abietatrien-7-one (1), villosin A (2), salvinolone (3), 14-deoxyloleon U (4), 5,6-dehydrosugiol (5), and coleon U (6). Compounds 1, 2, 3, and 5 are reported for the first time for this genus. Compounds 1, 2, and 6 demonstrated potent cytotoxic activities against the HL-60 tumor cell line.     

1-O-Substituted derivatives of murrayafoline A and their antifungal properties

The synthesis of some 1-oxygenated derivatives of murrayafoline A (1) and their antifungal properties is reported. Three derivatives, 1-hydroxy-3-methyl-9H-carbazole (2), 1-(3-methylbut-2-enyloxy)-3-methyl-9H-carbazole (3) and 1-(2,3,4,6,-tetra-O-acetyl-alpha-D-O-glucopyranosyl)-3-methyl-9H-carbazole (4), of murrayafoline A were synthesized. Compounds 1 and 2 exhibit strong fungicidal activity against Cladosporium cucumerinum at the dose of 12.5 microg.     

Antioxidant hispidin derivatives from medicinal mushroom Inonotus hispidus

Two natural antioxidants, named inonotusin A (1) and B (2), were isolated from the methanolic extract of the fruit bodies of Inonotus hispidus, together with (E)-4-(3,4-dihydroxyphenyl)but-3-en-2-one (3), hispidin (4) and 3,4-dihydroxybenzaldehyde (5). Their structures were identified by means of extensive NMR and MS data analysis. Compounds 1, 2 and 4 exhibited significant scavenging activity against the 2,20-azinobis(3-ethylbenzhiazoline-6-sulfonate) (ABTS) radical cation. Compound 1 also showed moderate cytotoxicity against a human breast carcinoma cell line (MCF-7) with IC(50) values of 19.6 μM.     

Synthesis and antitubercular activity of substituted novel pyrazoline derivatives

A series of 2-2-methoxy-4-[5-(substituted phenyl)1-(4-pyridylcarbonyl)-4,5-dihydro-1H-3-pyrazolyl] phenoxyacetic acid were synthesized by the reaction between isoniazid (INH) and chalcones, and were tested for their antimycobacterial activity in vitro against Mycobacterium tuberculosis H37Rv and INH resistant M. tuberculosis using BACTEC-460 radiometric system and agar dilution method. Among the synthesized compounds, Compounds II 2-4-[5-(4-hydroxyphenyl)-1-(4-pyridylcarbonyl)-4,5-ihydro-1H-3-pyrazolyl]-2-methoxy phenoxy acetic acid was found to be most active agent against M. tuberculosis H37Rv (MTB) and INH resistant M. tuberculosis (INHR-MTB), with minimum inhibitory concentration of 0.12 microM, when compared to INH 5.6-fold more active against MTB and 78-fold more active against INHR-MTB, respectively.     

Indole Alkaloids from Alocasia macrorrhiza

Five new indole alkaloids, alocasins A-E (3-7), together with known hyrtiosin B (1) and hyrtiosulawesin (2) were isolated from Alocasia macrorrhiza (L.) SCHOTT; their structures were elucidated on the basis of spectroscopic data. Compounds 1-7 were in vitro tested for cytostatic activity on human throat cancer (Hep-2), human hepatocarcinoma (Hep-G2), and human nasopharyngeal carcinoma epithelial (CNE) cell lines by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method; compounds 2, 3, 6 and 7 showed mild antiproliferative activity against Hep-2 and Hep-G2 whereas compounds 2 and 4 showed gentle antiproliferative activity against CNE.     

Ceanothane- and lupane-type triterpenes with antiplasmodial and antimycobacterial activities from Ziziphus cambodiana

One new and eight known ceanothane- and lupane-type triterpenes were isolated from the root bark of Ziziphus cambodiana PIERRE (Rhamnaceae). Based on spectral analyses, the structure of the new compound was elucidated as 3-O-(4-hydroxy-3-methoxybenzoyl)ceanothic acid (3-O-vanillylceanothic acid) (1), while the known compounds were identified as lupeol (2), betulinaldehyde (3), betulinic acid (4), 2-O-E-p-coumaroyl alphitolic acid (5), alphitolic acid (6), zizyberanalic acid (7), zizyberenalic acid (8) and ceanothic acid (9). Compounds 1, 5 and 8 exhibited significant in vitro antiplasmodial activity against the parasite Plasmodium falciparum, with inhibitory concentration (IC50) values of 3.7, 0.9 and 3.0 microg/ml, respectively. Compounds 1 and 3-8 showed antimycobacterial activity against Mycobacterium tuberculosis with respective MIC values of 25, 25, 25, 12.5, 50, 50 and 100 microg/ml.     

Two novel alkaloids from the stem of Saprosma hainanense and their cytotoxic activities in vitro

Two novel alkaloids, saprosmine A (1) and saprosmine B (2), were isolated from the stem of Saprosma hainanense MERR., along with five known alkaloids: marcanine A (3); cleistopholine (4); 4-methoxycarbonyl-5,10-benzogquinolinequinone (5); liriodenine (6); and quinoline (7). The chemical structures were established on the basis of extensive spectroscopic (IR, 1D-NMR, 2D-NMR, MS) data analysis and by comparison with spectroscopic data reported in the literature. Compounds 1 to 6 were evaluated for in vitro cytotoxic activities against the SPC-A-1 (human lung cancer), BEL-7402 (human hepatocellular carcinoma), SGC-7901 (human gastric cancer), and K-562 (human myelogenous leukaemia) cancer cell lines. Compounds 1 and 2 exhibited weak cytotoxic activities against K-562 cells. Compounds 3 and 5 showed cytotoxic activities against all four cancer cell lines.     

COX-1, COX-2 inhibitors and antifungal agents from Croton hutchinsonianus

Two new compounds, 3'-(4'-hydroxy-3',5'-dimethoxyphenyl)-propyl benzoate (1) and 3'-(4'-hydroxyphenyl)-propyl benzoate (3) together with known compounds, 3'-(4'-hydroxy-3'-methoxyphenyl)-propyl benzoate (2), poilaneic acid (4), farnesyl acetone (5) and 4-hydroxybenzaldehyde (6) were isolated and identified from the branches of Croton hutchinsonianus. Their structures were determined by spectroscopic methods. The three phenylpropyl benzoates (1-3) were found to exhibit antifungal activity against Candida albicans (IC(50) 5.36-11.41 microg/ml). Compounds 1-2 (IC(50) 2.11-4.95 microg/ml) exhibited potent but non-selective activity against the enzymes cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) whereas 3 (IC(50) 1.88 microg/ml) preferentially inhibited the enzyme COX-2.