New secondary metabolites from an engineering mutant of endophytic Streptomyces sp. CS.

In previous work, a series of bioactive natural products had been isolated from the plant endophytic Streptomyces sp. CS, which was isolated from Maytenus hookeri. To mine new active metabolites, we describe introducing an alien carbamoyltransferase (asm21) gene into the strain CS by conjugal transfer. As a result, three recombinatorial mutants named CS/asm21-1, CS/asm21-2 and CS/asm21-4 were successfully constructed. Three mutants and wild type CS were cultured on solid medium, and the extracts were detected and analyzed by liquid chromatography-mass spectrometry (LC-MS). The LC-MS profiles showed several unknown peaks that were present in the spectra of extracts of the CS/asm21-4 cultured on oatmeal solid medium. Then, three new naphthomycins O-Q (1-3), a new macrolide hookerolide (4) as well as nine known compounds were obtained from the solid cultured medium. Their structures were identified by spectra data. These new compounds showed moderate antimicrobial activities.

Four novel antibacterial sesquiterpene-α-amino acid quaternary ammonium hybrids from the mycelium of mushroom Stereum hirsutum.

The mushroom Stereum hirsutum is parasitized by Tremella aurantia to form a heterogeneous basidiocarp Jin'er, which has been used as food and folk medicine in Chinese society. In present work, the S. hirsutum was fermented in YMG broth, and four novel mixed terpenes, stereumamides A-D (1-4), which are sesquiterpenes combined with α-amino acids to form quaternary ammonium hybrids, were isolated from the Stereum hirsutum FP-91666 and their structures were elucidated by spectroscopic data analysis. Stereumamides A and D showed antibacterial activity against Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium, with the minimum inhibitory concentration (MIC) values of 12.5-25.0 µg/mL. The stereumamides A-D should be apparently the first example of naturally occurring a quaternary ammonium compound (QAC) conjugated by sesquiterpene with an α-amino acid. QAC is a common antibacterial agent in food industry, which is found in the mycelium of Stereum hirsutum would suggest that the complex basidiocarp is a functional food and veritable folk medicine.

Four new steroids from the endophytic fungus Chaetomium sp. M453 derived of Chinese herbal medicine Huperzia serrata.

An endophytic fungus, Chaetomium sp. M453, was isolated from Huperzia serrata (Thunb. ex Murray) Trev. and subjected to phytochemical investigation. Three unusual C25 steroids, neocyclocitrinols E-G (1-3), and 3ß-hydroxy-5,9-epoxy-(22E,24R)-ergosta-7,22-dien-6-one (4) together with three known steroids were isolated from solid fermentation products of the fungus, which were elucidated by extensive spectroscopic analyses, including 1D-, 2D-NMR, and HR-ESI-MS experiments. The absolute configuration of 1 was determined by X-ray crystallographic analysis and CD analyses. The acetylcholinesterase inhibitory activities of compounds 1-4 were tested in vitro. Compound 4 showed weak acetylcholinesterase inhibitory activity.

A new compound from Stereum insigne CGMCC5.57.

Studies of the EtOAc extract of the culture broth and methanol extract of the mycelium of Stereum insigne CGMCC5.57 led to the isolation of one new dihydrobenzofuran (1) and six known compounds (2-7). The structures of compounds were elucidated mainly by HRESIMS experiments, and 1D, 2D NMR spectroscopy analysis. This is the first report about the chemical constitutes of the fungus S. insigne.

A new agent developed by biotransformation of polyphyllin VII inhibits chemoresistance in breast cancer.

Biotransformation by the endophytes of certain plants changes various compounds, and this 'green' chemistry becomes increasingly important for finding new products with pharmacological activity. In this study, polyphyllin VII (PPL7) was biotransformed by endophytes from the medicinal plant Paris polyphylla Smith, var. yunnanensis. This produced a new compound, ZH-2, with pharmacological activity in vitro and in vivo. ZH-2 was more potent than PPL7 in selectively killing more chemoresistant than chemosensitive breast cancer cells. ZH-2 also re-sensitized chemoresistant breast cancer cells, as evidenced by the improved anti-cancer activity of commonly-used chemotherapeutic agent in vitro, in vivo, and in clinical samples. This anti-chemoresistance effect of ZH-2 was associated with inhibiting the epithelial-mesenchymal transition (EMT) pathway. Taken together, our findings are the first one to link biotransformation with a biomedicine. The results provide insights into developing new pharmacologically-active agents via biotransformation by endophytes.

Three new naphthoquinone pigments isolated from the freshwater fungus, Astrosphaeriella papuana.

Three new naphthoquinones, astropaquinones A-C (1-3), were isolated from cultures of the freshwater fungus Astrosphaeriella papuana YMF 1.01181, together with the known compound, 6-hydroxy-2,4-dimethoxy-7-methylanthraquinone (4). The structures of the compounds were settled mainly by interpretation of their 1D and 2D NMR spectra. Astropaquinone B (2) and C (3) were found to possess a rare pyranonaphthoquinone skeleton containing a lactol ring. Furthermore, compounds 1-4 showed moderate antagonistic activity against nine fungi and four bacterial strains.

Nematicidal cardenolides from Nerium indicum Mill.

Three nematicidal cardenolides were obtained from the AcOEt extract of Nerium indicum Mill. by bioassay-guided fractionation. They include a new compound, 3beta-O-(beta-D-diginosyl)-14,15alpha-dihydroxy-5alpha-card-20(22)-enolide (1), and two known compounds, uzarigenin (2) and cardenolide N-1 (3). The median lethal concentrations (LC(50)) of compounds 1-3 against the nematodes Bursaphelenchus xylophilus, Panagrellus redivivus, and Caenorhabditis elegans at 72 h were 103.3, 49.0, and 45.4 mg l(-1), 257.0, 62.7, and 177.8 mg l(-1), and 242.9, 29.1, and 41.7 mg l(-1), respectively. This is the first report about the nematicidal activity of cardenolides.

[Effects of tetrandrine on nuclear factor-kappaB expression in leukemia multidrug-resistant cell line K562/A02].

OBJECTIVE: To investigate the effects of tetrandrine (Tet) on nuclear factor kappaB (NF-kappaB) expression in leukemia cell line K562 and multidrug-resistant K562/A02 cell line. METHODS: The activations of NF-kappaB in K562 and K562/A02 cells and the effects of 1 micromol/L Tet on NF-kappaB expression were determined by immunocytochemistry and Western blot assay. RESULTS: Tet had no effect on NF-kappaB expression in K562 cells after 6- and 12-hour treatment (P>0.05), and K562/A02 cells displayed higher level of NF-kappaB protein expression than their parental K562 cells (P<0.01). Tet could significantly down-regulate NF-kappaB protein expression and nuclear translocation in K562/A02 cells shown by immunocytochemistry and Western blot, and this decrease became more significant after 12-hour treatment than after at 6-hour treatment (P<0.05). CONCLUSION: Activation of NF-kappaB may be related to multidrug resistance of K562/A02 cell line. And the inhibition of NF-kappaB activation by Tet leads to multidrug resistance reversal in K562/A02 cell line.

Nematicidal coumarins from Heracleum candicans Wall.

The root extract of Heracleum candicans Wall. exhibited antagonistic activities against nematodes Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle and Panagrellus redivivus (Linn.) Goodey. Through bioassay-guided fractionations, three coumarins were obtained from the extract of H. candicans and determined to be 8-geranyloxypsoralen (1), imperatorin (2), and heraclenin (3) based on spectra data. All three compounds possessed nematicidal activities against the two tested nematodes. The median lethal concentrations (LC(50)) of compounds 1-3 at 72 h were 188.3, 161.7, and 114.7 mg L(-1) respectively against B. xylophilus and were 117.5, 179.0, and 148.7 mg L(-1) respectively against P. redivivus. This is the first report about species in the Umbelliferae family that possesses nematicidal activity.

Nematicidal metabolites produced by the endophytic fungus Geotrichum sp. AL4.

From the endophytic fungal strain Geotrichum sp. AL4, cultivated from the leaves of the neem tree (Azadirachta indica), four compounds, 1-4, were isolated from the AcOEt extract, including two new, chlorinated, epimeric 1,3-oxazinane derivatives. All compounds were assessed for their nematicidal activities against the nematodes Bursaphelenchus xylophilus and Panagrellus redivivus, and three out of the four isolates showed noticeable bioactivities.

[The fermentation of 50 kinds of TCMs by Bacillus subtilis and the assay of antibacterial activities of fermented products].

50 Traditional Chinese medicines (TCMs) were fermented by Bacillus subtilis and the antimicrobial activities of the fermented products were assayed against Mycobacterium tuberculosis and Penicillium avellaneum. The results showed that some products of them had stronger antimicrobial activities, but some weaker than the corresponding raw materials, still some had no change, which indicated that microorganism and TCM can effect each other during fermentation.

Nematicidal activity and chemical component of Poria cocos.

Poria cocos, a famous traditional Chinese medicine, was found to have nematicidal activity in experiments searching for nematicidal fungi. The experiment showed it could kill 94.9% of the saprophytic nematode, Panagrellus redivivue, 92.6% of the root-knot nematode, Meloidogyne arenaria, and 93.5% of the pine nematode, Bursaphelenchus xylophilus, on PDA plate within 12 hours. According to the nematicidal activity, three new compounds, 2, 4, 6-triacetylenic octane diacid, 2, 4, 5, 6-tetrahydroxyhexanoic acid and 3, 4-dihydroxy-2-keto-n-butyl 2,4,5,6-tetrahydroxyhexanate, were isolated from submerged cultures of Poria cocos. Of these, 2, 4, 6-triacetylenic octane diacid could kill 83.9% Meloidogyne arenaria and 73.4% Panagrellus redivivus at 500 ppm within 12 hours. Here, it is reported for the first time that Poria cocos has nematicidal activity.