The antibacterial and antifungal activities of the acetone extract from Paullinia cupana var. sorbilis Mart. (Sapindaceae) seeds, commonly called guarana, were assessed against selected bacterial and fungal strains. We tested the extract against both standard American Type Culture Collection (ATCC) and clinically isolated (CI) bacterial strains and three fungal strains. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values for bacteria and MIC and minimum fungicidal concentration for fungi were determined. The extract showed an activity against the nine bacterial strains tested, both CI and ATCC strains (MIC comprised between 32 and 128 μm/mL and MBC between 128 and 512 μm/mL), showing a significant antibacterial effect against both Gram-negative and Gram-positive bacteria. Also, the tested fungi were sensitive to the extract (MIC between 125 and 250 μm/mL). The contemporaneous presence of different bioactivities in the extract from guarana suggests this plant as a source of bioactive substances.

A new indoloquinazoline alkaloidal glucoside, rutaecarpine-10-O-β-d-glucopyranoside (1), together with one known alkaloidal glycoside namely rutaecarpine-10-O-rutinoside (2) was isolated from the nearly ripe fruits of Evodia rutaecarpa (Juss.) Benth.. Their structures were elucidated on the basis of extensive spectroscopic methods.

A new biphenyl, named schomburgbiphenyl (1), and 14 known compounds were isolated from the wood of Garcinia schomburgkiana. The known constituents were identified as follows: three xanthones (2, 8 and 9), two benzophenones (3 and 4), three biphenyls (5-7), three biflavonoids (10-12) and three steroids. Compounds 3 and 4 were highly cytotoxic to SW620 cell line (100 times more than the positive control, doxorubicin) and were also strongly active against KATO-III, HepG2 and CHAGO cell lines. Compound 6 was specifically cytotoxic towards SW620 cells, whereas compound 8 displayed strong cytotoxicity against all five cell lines tested.

Bacillus sp. associated with an entomopathogenic nematode is shown to produce diketopiperazine (DKP) that showed stronger antifungal activity against Colletotrichum gloeosporioides [minimum inhibitory concentration (MIC): 8 μg mL(- 1)] than commercial fungicide oligochitosan (MIC: 125 μg mL(- 1)). DKP identified as cyclo(d-Tyr-l-Leu) was isolated for the first time from a natural source with a d-tyrosine residue. This report also demonstrates for the first time an antifungal property exploration of cyclo(Tyr-Leu) class of dipeptides. The structural elucidation was carried out using 1D, 2D NMR methods and HPLC.

A rapid method was developed to quantify diosgenin in Rhizoma Dioscoreae Zingiberensis. For the first time, sample solution was prepared by coupling pretreatment of raw material in cellulase and two-phase acid hydrolysis. After reconstitution, analysis was carried out on a C18 column, at 30°C, with acetonitrile and water (70:30, v/v) as mobile phase with flow rate of 1.0 mL min(- 1). Detection was carried out at 202 nm. Good linearity (r (2) = 0.9998) was established between concentration of analyte and peak area. The precision was >99% and the RSD of diosgenin contents for repeatability was 1.81%. The accuracy was supported with recoveries at 98.8%, 101.6% and 101.2%. The sample solution prepared using the proposed method contained higher content of diosgenin and was stable for 48 h. Due to the high efficiency of sample preparation and high reliability of the HPLC method, it is feasible to use this method for routine analysis of diosgenin in the herb.

Two new compounds, 5-methoxy-3',4'-dihydroxy-6,7-methylenedioxy-4H-1-benzo-pyran-4-one(iriskashmirianin A) (1) and 5,3'-dihydroxy-3-(4'-β-d-glucopyranosyl)-6,7-methylenedioxy-4H-1-benzo-pyran-4-one (germanaism H) (2), along with eight known compounds (3-10), were isolated from the rhizomes of Iris germanica L. The cytotoxicities of these compounds were tested using Ehrlich's ascites carcinoma (EAC) cancer cell line by 3-(4, 5-dimethylthiazole-2-yl)-2, 5-diphenyltetrazoli-umbromide (MTT) and ATP assays. The results showed that these compounds possessed antiproliferative effects on EAC cell line. Among them, compound 1 possessed the best cytotoxic activity with IC50 ± SD of 20.9 ± 2.7 and 4.3 ± 0.9 μM for MTT and ATP assay methods, respectively.

Chemical investigation of the marine Streptomyces sp. Eg25 led to the isolation of one new natural 2-aminophenoxazin-3-one-8-carboxylic acid methyl ester named maroxazinone (1) as well as the known compounds elloxazinone A (2), exfoliazone (3), carboxyexfoliazone (4), elloxazinone B (5) and venezueline D (6). The chemical structures of the isolated compounds were deduced from extensive studies of NMR ((1)H and (13)C NMR, (1)H-(1)H COSY, HMQC and HMBC) and mass spectra. The cytotoxic activities of the new maroxazinone (1) and venezueline D (6) against breast carcinoma cell line (MCF7), liver carcinoma cell line (HEPG2) and colon carcinoma cell line (HCT116) were investigated.

A new dammarane triterpene named mauritic acid (1) was isolated from the roots of Mauritia flexuosa L.f. The complete structural assignment of this new compound was elucidated from spectroscopic methods. Moreover, this compound was evaluated for its cytotoxicity against human cancer cell lines (OVCAR-8, PCM3, NCIH358M and different leukaemia cell strains). The mauritic acid presented significant cytotoxicity against OVCAR-8, PCM3 and NCIH358M cell lines with IC50 3.02, 2.39 and 6.19 μM, respectively. The triterpenes 1 and 2 were also tested for their antimicrobial activity against 15 strains of microorganisms, including fungi and bacteria, with the best minimal inhibitory concentration values ranging from 50.8 to 203.5 μM.

Methanolic extract of Capparis sinaica Veill was tested for its in vitro antiviral activity against highly pathogenic avian influenza strain H5N1 using plaque inhibition assay in Madin-Darby canine kidney. The results indicated that the extract possessed potent antiviral activity (100% inhibition at the concentration of 1 μg/ml). Based on this result, C. sinaica Veill was selected for further study by applying bioactivity-guided fractionation to isolate its antiviral principles. The fractions eluted with EtOAc and 25% MeOH in EtOAc were found to hold the antiviral activity. Further chromatographic separation of the fractions holding the antiviral activity led to the isolation of quercetin (1), isoquercetin (2) and rutin (3) for the first time from this species. The isolates showed reduction in the virus titre by 68.13%, 79.66% and 73.22% inhibition at a concentration of 1 ng/ml, respectively.

Four indanomycin-related antibiotics 2-5 were isolated from the cultured broth of marine Streptomyces antibioticus strain PTZ0016. Their structures were characterised as 16-deethylindanomycin (2), iso-16-deethylindanomycin (3), 16-deethylindanomycin methyl ester (4) and iso-16-deethylindanomycin methyl ester (5) on the basis of NMR, HR-ESI-MS and CD evidences. Compounds 3-5 are new additions to the class of indanomycin antibiotics. All isolated compounds showed in vitro activity against Staphylococcus aureus with minimal inhibitory concentration at 4.0-8.0 μg/ml.