Chemical constituents from Gnaphalium affine and their xanthine oxidase inhibitory activity.

Gnaphalium affine D. Don, a medicinal and edible plant, has been used to treat gout in traditional Chinese medicine and popularly consumed in China for a long time. A detailed phytochemical investigation on the aerial part of G. affine led to the isolation of two new esters of caffeoylquinic acid named (-) ethyl 1, 4-di-O-caffeoylquinate (1) and (-) methyl 1, 4-di-O-caffeoylquinate (2), together with 35 known compounds (3-37). Their structures were elucidated by spectroscopic data and first-order multiplet analysis. All the isolated compounds were tested for their xanthine oxidase inhibitory activity with an in vitro enzyme inhibitory screening assay. Among the tested compounds, 1 (IC50 11.94 µmol·L-1) and 2 (IC50 15.04 µmol·L-1) showed a good inhibitory activity. The current results supported the medical use of the plant.

Tomenphantadenine, an unprecedented germacranolide-adenine hybrid heterodimer from the medicinal plant Elephantopus tomentosus L.

An unusual adenine-substituted germacrane sesquiterpene lactone, tomenphantadenine (1), has been isolated from the whole plant of Elephantopus tomentosus L. The structure of this compound was established by comprehensive spectroscopic analysis including high resolution (HR) ESI-MS, 1D and 2D nuclear magnetic resonance (NMR) spectroscopic data. This compound features novel hybrid pattern of germacrane sesquiterpene with adenine through C-N linkage, and a possible biosynthetic pathway for it was proposed. Compound 1 showed potent antibacterial activity against the gram-positive Staphylococcus aureus and weak acetylcholinesterase (AChE) inhibitory activity.

Determination of the Main Nucleosides and Nucleobases in Natural and Cultured Ophiocordyceps xuefengensis.

Ophiocordyceps xuefengensis, a recently described species of Ophiocordycepsthat is associated with the larvae of Phassusnodus (Hepialidae) in the living root or trunk of the medicinal plant Clerodendrumcyrtophyllum, isthe largest known Cordycepsspecies and is recognized as a desirable alternative for natural Ophiocordycepssinensis. This study investigated the main nucleosides and nucleobases in natural and cultured Ophiocordycepsxuefengensis. The contents of the nucleosides and nucleobases in the natural and cultured samples were determined by reverse phase HPLC. The highest concentration of adenosine was found in the natural fruit body and the cultured stroma, with almost no adenosine in the cadaver of Phassusnodus. The contents of adenine, guanosine, uridine and uracil in the cultured mycelium were significantly higher than those in the natural sample. Inosine was only detected in the natural samples. Thymidine and 2-deoxyadenosine were only found in the cadaver of Phassusnodus. Cordycepin was not detected in the five samples examined. These results suggested that the cultured mycelium and cultured stroma of Ophiocordycepsxuefengensis might be a promising substitute for natural O. xuefengensis.

Adeninealkylresorcinol, the first alkylresorcinol tethered with nucleobase from Lasiodiplodia sp.

Adeninealkylresorcinol (1), an unusual alkylresorcinol with adenine-alkylresorcinol conjoined skeleton, was isolated from an endophytic fungus Lasiodiplodia sp. obtained from a traditional Chinese medicine Houttuynia cordata Thunb., together with three new biogenetically related compounds (2-4). Their structures were elucidated by comprehensive spectroscopic analysis, and the absolute configuration of 4 was determined by the modified Mosher's method and quantum chemical calculation. Among them, adeninealkylresorcinol (1) is the first alkylresorcinol tethered with nucleobase. In addition, the antioxidant, cytotoxic, and antimicrobial activities of 1-3 were evaluated.

Direct-acting DNA alkylating agents present in aqueous extracts of areca nut and its products.

Areca nut is a carcinogen to humans and has been strongly associated with oral premalignant and malignant diseases. Previous studies speculated the presence of unknown direct-acting mutagens present in aqueous extracts of areca nut. We hypothesized whether any direct-acting alkylating agents are present in areca nut and its commercial products. In this study, calf thymus DNA was treated with four different aqueous extracts obtained from unripe and ripe areca nuts or their commercial products, namely, pan masala (without tobacco) and gutkha (with tobacco). Three N-alkylated purines including N7-methylguanine (N7-MeG), N3-methyladenine (N3-MeA), and N7-ethylguanine (N7-EtG) were detected using sensitive and specific isotope-dilution liquid chromatography-tandem-mass spectrometry (LC-MS/MS) methods. The results showed that four types of aqueous extracts significantly induced the formation of N7-MeG and N3-MeA in a linear dose-response manner. Extracts from unripe areca nut exhibited higher methylating potency than those of ripe areca nut, while gutkha had higher methylating potency than pan masala. Meanwhile, gutkha made with areca nut and tobacco, was the only extract found to induce the formation of N7-EtG. Overall, this study first demonstrated that the presence of direct-acting alkylating agents in areca nut and its commercial products exist at a level that is able to cause significant DNA damage. Our findings may provide another mechanistic rationale for areca nut-mediated oral carcinogenesis and also highlight the importance and necessity of the identification of these direct-acting alkylating agents.

[Studies on the chemical constituents from the roots of Tinospora sagittata var. yunnanensis (II)].

OBJECTIVE: To study the chemical constituents from the roots of Tinospora sagittata var. yunnanensis. METHODS: Various chromatographic techniques were used to isolate and purify the constituents. The structures of these compounds were elucidated on the basis of spectral analysis. RESULTS: Seven compounds were isolated from the plant and their structures were identified as tinophylloloside (1), epitinophylloloside (2), 2-deoxycrustecdysone (3), polypodine B (4) , (+)-5'-methoxyisolariciresinol 3alpha-O-beta-D-glucopyranoside (5), geniposide (6), adenine (7). CONCLUSION: All compounds are isolated from the plant for the first time,and compounds 4, 5, 6 and 7 are isolated firstly from the genus.

Separation of adenine, adenosine-5'-monophosphate and adenosine-5'-triphosphate by fluidic chip with nanometre-order diameter columns inside porous anodic alumina using an aqueous mobile phase.

Adenine, adenosine-5'-monophosphate and adenosine-5'-triphosphate were separated by fluidic chip with PAA membranes using an aqueous mobile phase.

[Studies on the chemical constituents of Portulaca oleracea].

OBJECTIVE: To study the chemical constituents of Portulaca oleracea. METHODS: The constituents were isolated by column chromatography and identified on the basis of physicochemical and spectral data. RESULTS: Five compounds were isolated from 70% ethanol extract of this plant and their structures were elucidated as cyclo (Phe-Ile) (1), cycle (Tyr-Ala) (2), adenine (3), friedelin (4) and isoselachoceric acid (5). CONCLUSION: Compounds 1-5 are isolated from Portulaca oleracea for the first time.

[Study on HPLC fingerprint characteristic analysis of Cordyceps sinensis and its similar products].

OBJECTIVE: To study on HPLC fingerprint characteristic analysis of Cordyceps sinensis and its similar products. METHODS: To determinate 13 samples of Cordyceps sinensis and its similar products by HPLC, and analyze the HPLC results with similar appraisal method and graphical methods of multivariate sample in two dimensional plane such as the methods of profile, radar chart and constellation graph. RESULTS: The similar appraisal method might synthesize the similar degree in quantification, while the graphical methods such as profile graph, radar chart and constellation graph could show more details about the classification and the characteristic of varieties directly. CONCLUSIONS: We recommend the combined application of similar appraisal method and the graphical methods due to its advantages on the judgment and characteristic analysis of fingerprint.

[Studies on chemical constituents from the water-soluble part of root of Angelica dahurica].

OBJECTIVE: To study the chemical constituents in the root of Angelica dahurica. METHOD: The compounds were isolated and identified by column chromatography and 1H, 13C NMR data. RESULT: Eleven compounds were isolated and identified. CONCLUSION: Six compounds were isolated from this plant for the first time.

Formation of 1,N6-ethenoadenine and 3,N4-ethenocytosine by lipid peroxidation products and nucleic acid bases.

Lipid peroxidation (LPO) products are known to interact with DNA, yielding several types of adduct with nucleobases. In this study, we demonstrate the formation of two ethenobase adducts, 1,N6-ethenoadenine and 3,N4-ethenocytosine, by reaction of LPO products with nucleic acid bases. Rat liver microsomes were incubated at 37 degrees C for 30 min in the presence of inducers of LPO [Fe(II) or cumene hydroperoxide] and adenine or cytosine nucleotides or nucleosides, followed by further heating at 80 degrees C for 30 min to complete the reactions. The etheno adducts detected after immunoaffinity chromatography were 1,N6-etheno-cAMP and 1,N6-etheno-2'-deoxyadenosine (HPLC/fluorimetry), 3,N4-etheno-2'-deoxycytidine (competitive radioimmunoassay), and 1,N6-etheno-2'-deoxyadenosine 3'-monophosphate and 3,N4-etheno-2'-deoxycytidine 3'-monophosphate (32P-postlabeling). Incubation of arachidonic acid supplemented with Fe(II) also led to the formation of the 1,N6-etheno adduct from cAMP. LPO intermediates that may be involved are discussed. These data suggest that etheno adducts may be markers of DNA damage associated with LPO.

[Studies on constituents of ganoderma capense IV. The chemical structures of ganoine, ganodine and ganoderpurine].

Two novel pyrrole alkaloids--ganoine and ganodine and a novel purine alkaloid ganoderpurine have been isolated from the mycelium of Ganoderma capense (Lloyd)Teng (Polyporaceae) obtained by submerged fermentation. On the basis of spectroscopic data their structures were elucidated, ganoine is N-isopentyl-5-hydroxymethyl-pyrryl alldehyde. Ganodine is N-phenylethyl-5-hydroxymethyl-pyrryl aldehyde and ganoderpurine is N9-(alpha, alpha dimethyl-gamma-oxobutyl) adenine.

[Chemical constituents of Cordyceps mililaris (L.) Link].

Six constituents were isolated from the hypha of Jinlin Cordyceps mililaris. The structures were determined to be beta-sitosterol, ergosterol, D-mannitol, daenine adenosine and cordycepin (3'-deopadenosine). Cordycepin, ergosterol, adenine were isolated for the first time from this hypha of Jinlin C. mililaris.