Dendrazawaynes A and B, antifungal polyacetylenes from Dendranthema zawadskii (Asteraceae)

Two new C(14) polyacetylenes dendrazawayne A(7) and dendrazawayne B (9) together with known C(13) polyacetylenes (2, 3), C(14) polyacetylenes (1, 4, and 8) and polyacetylene amides (5 and 6) were isolated from the roots of Dendranthema zawadskii. The structures of 7 and 9 were elucidated based on spectroscopic methods including 2D-NMR, HR-TOF-MS, IR, and UV. Compounds 1, 2, 3, 5, and 6 showed moderate activity against tumor cell lines (human small lung cancer cell line A549, melanoma SK-Mel-2, and mouse melanoma B16F1) with IC(50) values in the range of 7.4 - 30 microg/mL. Compounds 7 and 9, including other polyacetylenes, showed strong activity against the fungus Trichophyton (MIC: 5 - 10 microg/mL).     

Synthesis and in vitro-anticancer and antimicrobial evaluation of some novel quinoxalines derived from 3-phenylquinoxaline-2(1H)-thione

Two novel series derived from 3-phenylquinoxaline-2(1H)-thione 2 and 2-(hydrazinocarbonylmethylthio)-3-phenylquinoxaline 6 have been synthesized. Eight out of twenty six new compounds were selected at the National Cancer Institute for evaluation of their in vitro-anticancer activity. Among them, compounds 3b, 3c, 4b, and 4c displayed moderate to strong growth inhibition activity against most of the tested sub-panel tumor cell lines with GI(50) 10(-5) to 10(-6 )molar concentrations. Compound 4b exhibited a significant value of percent tumor growth inhibition against breast cancer at concentration < 10(-8) M. Compound 4c showed moderate selectivity towards leukemia cell lines with GI(50) of 1.8 to 3.8 microM (selectivity ratio = 5.7). Preliminary antimicrobial testing revealed that compounds 7a, 7b, 8a, 11a, and 11b were as active as ampicillin against B. subtilis (MIC = 12.5 microg/mL). Compounds 7b and 8a were also nearly as active as ampicillin against E. coli (MIC = 12.5 microg/mL). In addition, compounds 4a, 7b, 10b, and 11a were as active as ampicillin against P. aerugenosa (MIC = 50 microg/mL). However, compounds 7b, 8a, and 10b showed mild activity against C. albicans (MIC = 50 microg/mL). The values of minimum bactericidal concentrations indicated that compounds 4a and 7b were bactericidal against B. subtilis and P. aerugenosa, respectively, while compound 10b was bactericidal against both organisms. However, compound 11a was bactericidal against E. coli, P. aerugenosa, and S. aureus.     

Cytotoxic terpene hydroperoxides from the aerial parts ofAster spathulifolius

Three new sesquiterpene hydroperoxides, 1-[3-(2-hydroperoxy-3-methylbut-3-en)-4-hydroxyphenyl]ethanone (2), 7beta-hydroperoxy-eudesma-11-en-4-ol (3), and 7alpha-hydroperoxymanool (4), together with three known compounds, germacrone (1), ent-germacra-4(15),5,10(14)-trien-1alpha-ol (5) and teucdiol A (6) were isolated from the aerial parts of Aster spathulifolius (Compositae). Their structures were characterized using chemical and spectroscopic methods. The isolated compounds were tested for their cytotoxicity against five human tumor cell lines in vitro using a SRB method. The two new compounds, 3 and 4, showed moderate cytotoxicity against human cancer cells with ED50 values ranging from 0.24 to 13.27 microg/mL.     

Coumarins and carbazoles from Clausena excavata exhibited antimycobacterial and antifungal activities

Four known coumarins, dentatin (1), nor-dentatin (2), clausenidin (3) and xanthoxyletin (5), and six known carbazole derivatives, 3-formylcarbazole (6), mukonal (7), 3-methoxycarbonylcarbazole (8), murrayanine (9), 2-hydroxy-3-formyl-7-methoxycarbazole (10) and clauszoline J (11) were isolated from Clausena excavata. Compounds 1 and 6 were first isolated from the crude chloroform extract of the rhizomes. Compounds 1, 2, 3, 6, 7, 8, 10 and 11 showed antimycobacterial activity at a minimum inhibitory concentration (MIC) of 50, 100, 200, 100, 200, 50, 100 and 100 microg/mL, respectively. O-Methylated clausenidin ( 4), prepared from 3, exhibited antimycobacterial activity at MIC 50 microg/mL. Compounds 6, 7, 8 and 10 showed antifungal activity with IC 50 values of 13.6, 29.3, 9.5 and 2.8 microg/mL, respectively. All compounds demonstrated no cytotoxicity against KB and BC-1 cell lines.     

Anti-tuberculosis constituents from the stem bark of Micromelum hirsutum

Anti-TB bioassay-directed fractionation led to the isolation of six carbazole alkaloids, as well as the gamma-lactone derivative of oleic acid, from the CH (2)Cl (2) extract of the stem bark of Micromelum hirsutum. The carbazoles include the new micromeline ( 2) and five known alkaloids: lansine ( 3), 3-methylcarbazole ( 4), methyl carbazole-3-carboxylate ( 5), 3-formylcarbazole ( 6), and 3-formyl-6-methoxycarbazole ( 7). Compound 1 was identified as the lactone derivative of oleic acid, (-)- Z-9-octadecene-4-olide, for which the trivial name micromolide ( 1) is suggested. It showed potent in vitro anti-TB activity against H37R v (MIC: 1.5 microg/mL), a selectivity index (SI) of 63, and exhibited activity against the Erdman strain of M. tuberculosis in a J774 mouse macrophage model (EC (90) : 5.6 microg/mL). Thus, 1 appears worthy of further evaluation as a potential new anti-TB agent. Isolates 2, 3, 6 and 7 had anti-TB MIC values between 14.3 and 42.3 microg/mL, while compounds 4 and 5 were considered inactive (MIC > 128 microg/mL). Structure elucidation and identification were based on spectroscopic analysis, including MS, 1D/2D NMR, and a full (1)H spin system analysis of 1.     

Synthesis of some novel substituted purine derivatives as potential anticancer, anti-HIV-1 and antimicrobial agents

In search of novel purine antimetabolites, a series of 8-substituted methylxanthine derivatives was prepared in order to explore their in vitro anticancer, anti-HIV-1 and antimicrobial activities. The target compounds include: 8-[(3-substituted-4-oxo-thiazolidin-2-ylidene)hydrazino]-1,3-dimethyl (or 1,3,7-trimethyl)-3,7-dihydropurine-2,6-diones 5a-e, 8-[(3,4-disubstituted 2,3-dihydrothiazol-2-ylidene)hydrazino]-1,3,7-trimethyl-3,7-dihydropurine-2,6-diones 6a-d and 8-(5-amino-3-arylpyrazol-1-yl)-1,3-dimethyl- (or 1,3,7-trimethyl)-3,7-dihydropurine-2,6-diones 7a-g. The in vitro anticancer results revealed that compound 5d exhibited a super sensitivity profile towards leukemia K-562 with a GI(50) value of <0.01 microM. Compound 7c showed significant activity against colon cancer HCT-15 and renal cancer CAKI-1 (GI(50) values of 0.47 and 0.78 microM, respectively). Compound 7a displayed high activity against colon cancer HCT-15 (GI(50 )= 0.8 microM). The anti-HIV-1 results indicated that compound 6b displayed a good reduction of viral cytopathic effect (56.69%). The antimicrobial results showed that compound 5a was four times more active than ampicillin against P. aerugenosa (MIC =or< 25 microg/mL), compound 5b had twice the activity of ampicillin, while compounds 5d, 7c and 7f were equipotent to ampicillin. On the other hand, compound 7a was equipotent to ampicillin against P. vulgaris (MIC = 50 microg/mL).     

Cytotoxic C-benzylated chalcone and other constituents ofEllipeiopsis cherrevensis

A new natural C-benzylated chalcone, 2',4'-dihydroxy-3'-(2-hydroxybenzyl)-6'-methoxychalcone (2), along with two other flavonoids, tiliroside and kaempferol 3-O-rutinoside, and an oxoaporphine alkaloid, lanuginosine were isolated from the aerial parts of Ellipeiopsis cherrevensis (Annonaceae). Two known polyoxygenated cyclohexene derivatives, ferrudiol and zeylenol, and a new analog, ellipeiopsol D, were also isolated. The chalcone 2 exhibited cytotoxic activity against human small-cell lung-cancer (NCI-H187), epidermoid carcinoma (KB) and breast cancer (BC) cell lines with IC50 values of 1.40, 5.31 and 13.92 microg/mL, respectively. This compound also showed antimalarial activity against Plasmodium falciparum with an IC50 value of 7.1 microg/mL as well as antimicrobacterial activity against Mycobacterium tuberculosis with a MIC of 25 mg/mL.     

Synthesis, in vitro-antimycobacterial activity and cytotoxicity of some alkyl alpha-(5-aryl-1, 3, 4-thiadiazole-2-ylthio)acetates

A new series of alkyl alpha-[5-(5-nitro-2-furyl)-1, 3, 4- thiadiazole-2-ylthio] and alpha-[5-(1-methyl-5-nitro-2-imidazolyl)-1, 3, 4-thiadiazole-2-ylthio]acetates (6a-e, 6f-j) were synthesized and evaluated against Mycobacterium tuberculosis as part of the TAACF (Tuberculosis Antimicrobial Acquisition and Coordinating Facility) TB screening program. Primary screening was conducted at the single concentration of 6.25 microg/mL against M. tuberculosis H(37)Rv in BACTEC 12B medium using a broth microdilution assay, the Microplate Alamar Blue Assay (MABA). The minimum inhibitory concentration (MIC) was determined for compounds demonstrating >90 % growth inhibition in the primary screening. Seven compounds were efficient antimycobacterial agents showing MIC values ranging from 0.78 to 6.25 microg/mL. Among nitrofuran derivatives, methyl (6a), ethyl (6b), and benzyl (6e) esters displayed a good antituberculosis activity (MIC=0.78-3.13 microg/mL) and the others were inactive. In the nitro imidazole series, methyl (6f), ethyl (6g), propyl (6h) and butyl (6i) esters showed significant activity against M. tuberculosis while benzyl (6j) ester was inactive. Also, active compounds were screened by serial dilution to assess toxicity to a VERO cell line. A varying degree of toxicity was observed in nitrofuran and nitroimidazole derivatives (IC(50) = 2.3 - >10 microg/mL).     

Electron-microscopic study of the bactericidal effect of OPB-2045, a new disinfectant produced from biguanide group compounds, against methicillin-resistant Staphylococcus aureus

The bactericidal effect of OPB-2045, a new disinfectant produced from biguanide group compounds, against methicillin-resistant Staphylococcus aureus (MRSA), MRSA IID 1677, was investigated by transmission electron microscopy. OPB-2045 showed strong bactericidal activity against MRSA. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of OPB-2045 against the test strain were 0.78 and 1.56 microg mL(-1), respectively. The test bacteria were incubated in the presence of OPB-2045 at 1/2 MIC (0.39 microg mL(-1)), 1 MIC (0.78 microg mL(-1)), 2 MIC (1 MBC, 1.56 microg mL(-1)), 4 MIC (2 MBC, 3.13 microg mL(-1)) or 10 MIC (5 MBC, 7.8 microg mL(-1)) at 37 degrees C for 30 s, 3 min, 30 min or 6h. The morphology of the cells was examined by transmission electron microscopy. The cell damage observed after 30-min or 6-h incubation in the presence of OPB-2045 at 1/2 or 1 MIC was the same as that at 2, 4 or 10 MIC. The numbers of damaged MRSA cells increased according to the increase in concentration of added disinfectant, and the image of bacteriolysis was observed, too. After treatment at 1/2 or 1 MIC, a few leaking cells were recognized, but no destroyed cells were found. No morphological changes were observed after treatment at 1 or 2 MIC for 30 s, 3 min or 30 min. When the incubation time was extended to 6 h, morphological changes in the MRSA cells treated at 1 or 2 MIC were observed. When examining the relationship between the numbers of surviving bacteria and the MIC (MBC) values in soybean casein digest broth, no decrease in MRSA cell numbers was recognized in the untreated control or at 1/2 MIC, but a marked decrease in MRSA cell numbers was recognized as the OPB-2045 concentration was increased. The new disinfectant OPB-2045 would make a useful contribution to the medical field for the prevention of infections caused by pathogenic bacteria such as MRSA.     

Novel heteroarotinoids as potential antagonists of Mycobacterium bovis BCG

A series of 15 heteroarotinoids has been prepared and evaluated for activity against Mycobacterium bovis BCG with the thiourea-containing isoxyl (7) (0.5 microg/mL) as the standard. 2,2,4-Trimethyl-2H-chromen-7-yl 4-(methoxycarbonyl)benzoate (8) displayed the most significant activity (2.0-4.0 microg/mL) in terms of the lowest concentration (microg/mL) (MIC, minimum inhibitory concentration) required to produce a 99% reduction in the number of colonies on a plate as compared to that system free of the agent at the same dilution of the culture suspension. Ethyl 4-[[N-(2,2,4,4-tetramethylchroman-6-yl)thiocarbamoyl]amino]benzoate (9) and [[(1E,3Z,5E)-1-aza-4-methyl-6-(1,2,2,4-tetramethyl(1,2-dihydroquinolyl))hexa-1,3,5-trienyl]amino]aminomethane-1-thione (10) exhibited activity at 5.0-10.0 and 10.0-20.0 microg/mL, respectively, while the other examples had MIC values of 20 microg/mL or greater. The inhibitory ability of 8 may occur via the inhibition of mycolic acid synthesis in a like manner as found with 7, but this requires further study. The heteroarotinoids are the first examples to exhibit inhibitory ability against the growth of Mycobacterium bovis BCB.     

Pytochemical constituents of the aerial parts from<Emphasis Type="Italic">solidago virga-aurea var. gigantea</Emphasis>

The chromatographic separation of the MeOH extract of the aerial parts of Solidago virga-aurea var. gigantea M(IQ) (Compositae) led to the isolation of six terpenoids and four phenolic compounds, trans-phytol (1), ent-germacra-4(15),5,10(14)-trien-1alpha-ol (2), beta-amyrin acetate (3), ent-germacra-4(15),5,10(14)-trien-1beta-ol (4), beta-dictyopterol (5), oleanolic acid (6), kaempferol (7), kaempferol-3-O-rutinoside (8), methyl 3,5-di-O-caffeoyl quinate (9), and 3,5-di-O-caffeoyl quinic acid (10). Their structures were established by chemical and spectroscopic methods. Compounds 4, 5, and 10 showed moderate cytotoxicity against five cultured human tumor cell lines in vitro with its ED50 values ranging from 1.52 to approximately 18.57 microg/mL.     

Anthocleistenolide, a new rearranged nor-secoiridoid derivative from the stem back of Anthocleista vogelii

A new rearranged nor-secoiridoid, anthocleistenolide ( 1), along with the known 1-hydroxy-3,7-dimethoxyxanthone ( 2), 1-hydroxy-3,7,8-trimethoxyxanthone ( 3), 7 alpha-hydroxysitosterol ( 4) and sitosterol 3- O-beta- D-glucopyranoside ( 5), were isolated from the stem back of Anthocleista vogelii. Their structures were elucidated on the basis of spectral studies and comparison with published data. Compounds 1 - 3 and 5 were evaluated for their antibacterial and antifungal activities. Relatively low anti-staphylococcal (MIC = 200 microg/mL against Staphylococcus aureus) and anti-enterococcal (MIC = 100 microg/mL against Enterococcus faecalis) activities were observed for 1, while compounds 2 and 3 were active against Candida parapsilosis (MIC = 200 microg/mL for 2 and 25 microg/mL for 3). Compound 5 was inactive against all the bacterial and fungal species used.     

Isolation of limonoids and alkaloids from<Emphasis Type="Italic">Phellodendron amurense</Emphasis> and their multidrug resistance (MDR) reversal activity

Three limonoids and five alkaloids were isolated from the chloroform layer of the MeOH extract of the bark of Phellodendron amurense (Rutaceae). The structures of the compounds isolated were determined to be obacunone (1), limonin (2), 12alpha-hydroxylimonin (3), gamma-fagarine (4), oxyberberine (5), canthin-6-one (6), 4-methoxy-N-methyl-2-quinolone (7) and oxypalmatine (8) based on the physicochemical and spectroscopic data. Compounds 3, 5, 7, and 8 were first isolated from the Phellodendron amurense. The isolated compounds were then tested for their cytotoxicity against five human tumor cell lines in vitro using the SRB method. Compound 5 showed significant cytotoxicity against the five tumor cell lines with ED50 values ranging from 0.30 to 3.0 microg/mL. The marginal or noncytotoxic compounds (1, 2, 3, 4, and 7) were examined for their P-gp related MDR reversal activities. Compound 1 showed significant P-gp MDR inhibition activity in MES-SA/DX5 and HCT15 cells with an ED50 value of 0.028 microg/mL and 0.0011 microg/mL, respectively.     

Two new benzofuranes from Eupatorium aschenbornianum and their antimicrobial activity

Through a bioassay-guided fractionation, from the aerial parts of the medicinal plant Eupatorium aschenbornianum were isolated two new benzofurane compounds, 5-acetyl-3beta-angeloyloxy-2beta-(1-hydroxyisopropyl)-2,3-dihydrobenzofurane ( 1) and 5-acetyl-3beta-angeloyloxy-2beta-(1-hydroxyisopropyl)-6-methoxy-2,3-dihydrobenzofurane ( 2) in addition to 4-hydroxy-3,5-diprenylacetophenone, espeletone ( 3), encecalinol ( 4), beta-sitosterol and stigmasterol. The antimicrobial evaluation of these natural products showed that 1 [MIC = 200 microg/mL against T. mentagrophytes and 100 microg/mL against T. rubrum], 2 [MIC = 50 microg/mL towards both] and 3 [MIC = 100 microg/mL against both] were active against dermatophytes, while 4 was active against all of microorganisms assayed [MIC = 12.5 microg/mL ( T. mentagrophytes), 12.5 microg/mL ( T. rubrum), 100 microg/mL ( C. albicans) and 200 microg/mL ( A. niger)].     

Antibacterial effects of moxifloxacin and levofloxacin simulating epithelial lining fluid concentrations against community-acquired methicillin-resistant Staphylococcus aureus

BACKGROUND AND OBJECTIVE: Current North American guidelines advocate the use of respiratory fluoroquinolones for the empirical management of community-acquired pneumonia (CAP). While community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged as a pathogen frequently encountered in skin and skin structure infections, it has also now been recognised as a causative pathogen in CAP. Since fluoroquinolones may be used empirically to treat unsuspected CA-MRSA pneumonia, the objective of this study was to evaluate the antibacterial properties of levofloxacin and moxifloxacin using human simulated drug exposures in epithelial lining fluid (ELF). METHODS: An in vitro model was used to simulate the ELF concentrations, previously determined in older adults receiving multiple doses, of levofloxacin 500 mg once daily and moxifloxacin 400mg once daily. Four CA-MRSA isolates were studied at a starting inoculum of 10(6) colony-forming units (CFU)/mL; selected isolates were also studied at 10(8) CFU/mL. Bacterial density and resistance were quantitatively assessed over 48 hours. Drug exposure (area under the concentration-time curve [AUC]) was confirmed using validated drug assays. RESULTS: At a standard 10(6) starting inoculum, sustained bacterial kill (3.6-4.5 log) with both fluoroquinolones was noted for CA-MRSA isolates 27 and 44 (AUC/minimum inhibitory concentration [MIC] = 383-3923). Despite an MIC of 8 microg/mL (AUC/MIC = 25) for isolate 3, levofloxacin displayed a 2.8 log kill, while moxifloxacin (MIC 1 microg/mL) sustained a 4.5 log kill (AUC/MIC = 207) over 48 hours. Against isolate 59, levofloxacin displayed no antibacterial effect (AUC/MIC = 3), while moxifloxacin with an MIC of 8 microg/mL (AUC/MIC = 31) killed 4.6 log. At a high inoculum (10(8)), both fluoroquinolones showed 5.2-5.6 log kill for the susceptible isolate (44), while moxifloxacin showed no antibacterial activity against isolate 59. Drug exposure (AUC/MIC) appeared to correlate well (r(2) = 0.99) with the change in log CFU/mL. Maximal activity was observed for both drugs at an AUC/MIC of approximately 30. CONCLUSION: When evaluated at human simulated ELF concentrations, both levofloxacin and moxifloxacin appeared to demonstrate sustained antibacterial activity for CA-MRSA isolates with MICs 相似文献   

New cytotoxic benzopyrans from the leaves ofMallotus apelta

Two new benzopyrans 6-[1'-oxo-3'(R)-hydroxy-butyl]-5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (1) and 6-[1'-oxo-3'(R)-methoxy-butyl]-5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (2) were isolated from the leaves of Mallotus apelta Muell.-Arg., (Euphorbiaceae). Their chemical structures were elucidated by spectroscopic analyses, especially by 1 D-, 2D-NMR and MS spectra. Compound 1 was found to have strong cytotoxic effect against two human cancer cell lines as human hepatocellular carcinoma (Hep-2, IC50: 0.49 microg/mL) and rhabdosarcoma (RD, IC50: 0.54 microg/mL), while compound 2 showed moderate activity against Hep-2 cell line (IC50, 4.22 microg/mL) by in vitro assay.     

Minor limonoids from Melia toosendan and their antibacterial activity

In this study five new limonoids, toosendone [24,25,26,27-tetra-nor-6alpha-acetoxy-21,22-epoxy-7alpha-tigloyl-1alpha,3alpha,28-trihydroxyapotirucalla-(apoeupha)-14,20,22-trien-12-one, 1] and 12-ethoxynimbolinins A-D (2-5), together with five known limonoids, 1-acetyltrichilinin (6), 1-cinnamoyltrichilinin (7), trichilinin B (8), 1,7-di-O-acetyl-14,15-deoxyhavanensin (9) and 12-O-methylnimbolinin B (10),were isolated from the fruits of Melia toosendan. Their structures and relative configurations were established based on spectroscopic analysis. Compound 4 exhibited significant antibacterial activity against the oral pathogen, Porphyromonas gingivalis ATCC 33 277, with an MIC value of 15.6 microg/mL. Compounds 7 and 8 were also active against P. gingivalis ATCC 33 277, with MIC values of 31.3 and 31.5 microg/mL respectively.     

Synthesis and potent antimicrobial activity of some novel 4-(5, 6-dichloro-1H-benzimidazol-2-yl)-N-substituted benzamides

A series of 4-(5, 6-dichloro-1H-benzimidazol-2-yl)-N-substituted benzamides were synthesized and evaluated for antibacterial and antifungal activities against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), methicillin-resistant S. epidermis (MRSE), Enterococcus faecalis, Escherichia coli and Candida albicans. Certain compounds inhibit bacterial growth with low MIC values (microg/mL). Among them, compounds 10 and 11 exhibited the greatest antibacterial activity with MIC values of 3.12 microg/mL against S. aureus, MRSA and MRSE.     

Cytotoxic effects of Coptis chinensis and Epimedium sagittatum extracts and their major constituents (berberine, coptisine and icariin) on hepatoma and leukaemia cell growth

1. The present study was conducted to evaluate the cytotoxic effects of Coptis chinensis and Epimedium sagittatum extracts and their major constituents on hepatoma and leukaemia cells in vitro. 2. Four human liver cancer cell lines, namely HepG2, Hep3B, SK-Hep1 and PLC/PRF/5, and four leukaemia cell lines, namely K562, U937, P3H1 and Raji, were used in the present study. 3. Of the two crude drugs, C. chinensis exhibited the strongest activity against SK-Hep1 (IC50 = 7 microg/mL) and Raji (IC50 = 4 microg/mL) cell lines. The IC50 values for C. chinensis on HepG2, Hep3B and PLC/PRF/5 cell lines were 20, 55 and 35 microg/mL, respectively. The IC50 values for C. chinensis on K562, U937 and P3H1 cell lines were 29, 29 and 31 microg/mL, respectively. 4. With the exception of HepG2 and Hep3B, the E. sagittatum extract inhibited the proliferation of all cell lines (SK-Hep1, PLC/PRF/5, K562, U937, P3H1 and Raji), with IC50 values of 15, 57, 74, 221, 40 and 80 microg/mL, respectively. 5. Interestingly, the two major compounds of C. chinensis, berberine and coptisine, showed a strong inhibition on the proliferation of both hepatoma and leukaemia cell lines, with IC50 values varying from 1.4 to 15.2 microg/mL and from 0.6 to 14.1 microg/mL, respectively. However, icariin (the major compound of E. sagittatum) showed no inhibition of either the hepatoma or leukaemia cell lines. 6. The results of the present study suggest that the C. chinensis extract and its major constituents berberine and coptisine possess active antihepatoma and antileukaemia activities.     

Antituberculosis agents x. synthesis and evaluation of<Emphasis Type="Italic">In Vitro</Emphasis> antituberculosis activity of 2-(5-nitro-2-furyl)- and 2-(1-methyl-5-nitro-1<Emphasis Type="Italic">H</Emphasis>-imidazol-2-yl)-1,3,4-thiadiazole derivatives

Two series of 2-(5-nitro-2-furyl)- and 2-(1-methyl-5-nitro-1H-imidazol-2-yl)-5-propyl, allyl and propargyl)thio-1,3,4-thiadiazoles (6a-f) and 2-(5-nitro-2-furyl)- and 2-(1-methyl-5-nitro-1H-imidazol-2-yl)-5-(nitrobenzyl)thio-1,3,4-thiadiazole derivatives (8a-f) have been synthesized and evaluated against Mycobacterium tuberculosis, as part of the TAACF TB screening program under direction of the US National Institute of Health, the NIAID division. Primary screening was conducted at a single concentration, 6.25 microg mL(-1), against M. tuberculosis H37Rv in BACTEC 12B medium, using the Microplate Alamar Blue Assay (MABA). The minimum inhibitory concentration (MIC) was determined for the compounds that demonstrated > or = 90% growth inhibition in the primary screening. A varying degree of antituberculosis activity (from 0-97% of growth inhibition) was observed with the alkylthio series (6a-f), and the nitroimidazole derivative with a propylthio group (6b) and the nitrofuran derivative with a propargylthio group (6e), were the most active compounds (MIC=3.13 and 1.56 microg mL(-1), respectively). Among the nitrobenzylthio derivatives (8a-f), all the ortho, meta and para nitrobenzyl isomers in the nitrofuran series exhibited good antituberculosis activity (MIC=3.13 microg mL(-1)), while the corresponding nitroimidazole analogues were completely inactive (Inhibition=0%).