Structure elucidation and NMR assignments for two new quinones from fructus rhodomyrti of <Emphasis Type="Italic">Rhodomyrtus tomentosa</Emphasis>

Two new quinones, 1,4,7-trihydroxy-2-methoxy-6-methylanthracene-9,10-dione (1) and compound 2, were isolated from fructus rhodomyrti of Rhodomyrtus tomentosa (Ari.) Hassk., which was collected from Guangdong Province. The structures were elucidated by 1D, 2D NMR, and HR-EI-MS spectroscopy methods. The cytotoxic activities of two compounds in vitro were tested. Compound 1 showed cytotoxicity against KB and KBv200 cell lines with IC50 of 17.1 and 19.5 )μg/mL, and compound 2 with IC50 of 18.1 and 25.4 )μg/mL, respectively.     

Carboxylic Acids from <Emphasis Type="Italic">Phyllanthus urinaria</Emphasis>

Five compounds, terephthalic acid mono-[2-(4-carboxy-phenoxycarbonyl)-vinyl] ester (1), (E)-3-(5′-hydroperoxy-2,2′-dihydroxy[1,1′-biphenyl]-4-yl)-2-propenoic acid (2), 3,4,5-trihydroxybenzoic acid (3), succinic acid (or butanedioic acid) (4), and 2,3,4,5,6-pentahydroxybenzoic acid (5), were isolated from Phyllanthus urinaria. The structures of these compounds were elucidated by means of spectral techniques including IR, MS, and 1D/2D NMR. 1 and 2 are new compounds.__________Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 14–17, January–February, 2005.     

A new flavonoid from Cudrania cochinchinensis

Chemical investigation of the ethanol extract of the roots of Cudrania cochinchinensis led to the isolation of a new flavonoid, (6S,12S,13R)-1-methoxy cyanomaclurin (1), together with seven known compounds, 1,3,5-trihydroxy-4-(3′-hydroxy-3′-methylbutyl)xanthone (2), 1,3,6-trihydroxy-4-prenylxanthone (3), 1,3,6,7-tetrahydroxyxanthone (4), 1,3,5,6-tetrahydroxyxanthone (5), 1,3,6-trihydroxy-5-methoxyxanthone (6), resveratrol (7) and oxyresveratrol (8). The structure of compound 1 was elucidated on the basis of 1D and 2D NMR spectra and the HR-ESI-MS data. The absolute stereochemistry was deduced via Rh₂(OCOCF₃)₄-induced CD and NOESY spectra.     

Chemical Constituents from the Hulls of <Emphasis Type="Italic">Oryza sativa</Emphasis> with Cytotoxic Activity

Five new compounds, orizaterpenol (1), orizaterpenoid (2), orizaterpenyl benzoate (3), orizanor-diterpenyl benzoate (4), and orizaditerpenyl benzoate (5), along with nine known compounds, were isolated and identified from the rice hulls of Oryza sativa. Their structures were elucidated with the help of different spectroscopic techniques. Orizaterpenol (1) and the known momilactone A (6) and B (7) were found to have cytotoxic effects against P388 murine leukaemia cells, while the other new and known compounds exhibited weak cytotoxicity.__________Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 146–151, March–April, 2005.     

A new xanthone derivative from mangrove endophytic fungus No. ZSU-H16

A new xanthone derivative, 3,5,8-trihydroxy-2,2-dimethyl-3,4,4-trihydro-2H,6H-pyrano[3,2-b]-xanthen-6one (1), together with three known compounds, 5,8-dihydroxy-2,2-dimethyl-2H,6H-pyrano[3,2-b]xanthen6-one (2), cyclo-(N-O-methyl-L-Trp-L-Ile-D-Pip-L-2-amino-8-oxo-decanoyl) (3), and cyclo-(Phe-Tyr) (4), was isolated from the mangrove endophytic fungus No. ZSU-H16 obtained from the South China Sea coast. Their structures were elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopic techniques. Compound 1 exhibited cytotoxicity against KB and KB_V 200 cells with IC₅₀ values greater than 50 μg/mL, respectively.     

Two new ceramides from <Emphasis Type="Italic">Zephyranthes candida</Emphasis>

Two new ceramides were isolated from the bulbs of Zephyranthes candida. Their structures were established as (2S,3S,4R,13E)-1,3,4-trihydroxy-2-[(2′R)-2′-hydroxytetracosanoylamino]-13-octadecene, named zephyranamide A (1) and (2S,3S,4R)-1,3,4-trihydroxy-2-octacosanoylaminohexadecene, named zephyranamide B (2). The structures of the new compounds were elucidated by spectral techniques including ¹H NMR, ¹³C NMR, as well as HSQC, HMBC, DEPT, and COSY.     

Oligoamide,a new lactam from the leaves of Angylocalyx oligophyllus

A new lactam, oligoamide (1), along with three known compounds (2–4), stigmasterol-3-O-β-D-glucopyranoside (2), formononetin (3) and (-)-pinitol (4) were isolated from the CH₂Cl₂/CH₃OH (1:1) extract of the leaves of Angylocalyx oligophyllus by chromatographic separation. Their structures were elucidated on the basis of spectroscopic analysis (UV, IR, MS, 1D, and 2D NMR). Compound 1 was found to have weak antioxidant and urease inhibitory potential.     

Arjunolic Acid Derivative Glycoside from the Stems of <Emphasis Type="Italic">Hedera colchica</Emphasis>

Five triterpenoid saponins were isolated from the stems of Hedera colchica K. Koch (Araliaceae). Two of them are new natural substances. HCS-A (1): 3-O-α-L-arabinopyranoside, 28-O-α-L-rhamnopyranosyl-(1→ 4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl-arjunolic acid. HCSt-B (2):3-O-β-D-xylopyranoside, 28-O-α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl-hederagenin. A derivative of arjunolic acid is described for the first time in the Araliaceae family. The chemical structures of isolated compounds were established on the basis of chemical and 1D and 2D NMR experiments.__________Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 39–41, January–February, 2005.     

Isolation and identification of a new neo-clerodane diterpenoid from Teucrium chamaedrys L.

Teucrium chamaedrys L. is an aromatic and medicinal plant used as traditional medicine. Aerial parts of the plant material were dried and extracted with hexane–dichloromethane (extract 1), ethyl acetate–dichloromethane (extract 2) and methanol–dichloromethane (extract 3) in a ratio of 1:1 at rt successively. The solvents were evaporated to give crude extracts. Extract 1 was suspended in water at 60°C then partitioned successively with hexane and ethyl acetate to give hexane and ethyl acetate portions. After the column chromatography (silica gel) of ethyl acetate extract, one new and four known compounds were isolated. The new compound was named as 1(12S,18R)-15,16-epoxy-2β,6β-dihydroxy-neo-cleroda-13(16),14-dien-20,l2-olide-l8,l9-hemiacetal (teuchamaedryn D) (4). The known compounds were teucrin A (1), dihydroteugin (2), teucroxide (3), syspirensin A (5). The chromatographic methods were also applied for extract 3 to isolate verbascoside (6) and teucrioside (7). The structure of isolated compounds was elucidated by spectroscopic methods including LC-TOF/MS, 1D NMR and 2D NMR.     

A new coumarin from stem bark of Mesua hexapetala

A new alkylated coumarin derivative, hexapetarin (1) along with three other xanthones, trapezifolixanthone (2), cudraxanthone G (3) and 1,3,7-trihydroxy-2,4-di (3-methyl-2-butenyl)xanthone (4), and four common triterpenoids, friedelin (5), stigmasterol (6), beta-sitosterol (7) and gamma-sitosterol (8) were isolated from the stem bark of Mesua hexapetala (Clusiaceae), a plant, native to Malaysia. The structures of these compounds were elucidated and determined using spectroscopic techniques such as NMR and MS. Anti-inflammatory activity assay indicated hexapetarin (1) to possess moderate anti-inflammatory activity, while 1,3,7-trihydroxy-2,4-di (3-methyl-2-butenyl)xanthone (4) gave very good activity.     

A new C-glucoside from <Emphasis Type="Italic">Commelina communis</Emphasis>

A new C-glucoside, 3,4-epoxy-5-hydroxymethyl benzoate 2-C-β-glucoside (1), together with a known alkaloid, 1H-indole-3-carbaldehyde (2), were isolated from the whole plant of Commelina communis L. The structures of these compounds were determined by 1D, 2D NMR and MS techniques. Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 51–52, January–February, 2009.     

A new ten-membered lactone from <Emphasis Type="Italic">Tubercularia</Emphasis> sp<Emphasis Type="Italic">.</Emphasis> TF5, an endophytic fungus of <Emphasis Type="Italic">Taxus mairei</Emphasis>

One new ten-membered lactone (1) named (Z)-4,6,9-trihydroxy-10-nonyl-3,4,5,6,9,10-hexahydrooxecin-2-one along with 5-methoxycarbonylmellein (2) and cytochalasin D (3) were isolated from the culture of the endophytic fungus strain Tubercularia sp. TF5, originally separated from the inner bark of Taxus mairei obtained in Fujian Province, Southeast China. The structures of compounds 1–3 were elucidated by spectroscopic methods. The antimicrobial and cytotoxic activities of 1 were analyzed but it showed no significant activities.     

Two new clerodane-type diterpenoids from Bornean liverwort Gottschelia schizopleura and their cytotoxic activity

The Bornean liverwort Gottschelia schizopleura was investigated phytochemically for the first time. Two new and four previously known clerodane-type diterpenoids were isolated from the MeOH extract of G. schizopleura through a series of chromatographic techniques. The structures of the new metabolites were established by analyses of their spectroscopic data (1D NMR, 2D NMR, HRESIMS and IR). All the isolated compounds 1–6 were tested against human promyelocytic leukaemia (HL-60), human colon adenocarcinoma (HT-29) and Mus musculus skin melanoma (B16-F10). Compound 1 and 2 showed active inhibition against HL-60 and B16-F10 cells.     

A new 3,4-dihydroisocoumarin isolated from <Emphasis Type="Italic">Botryosphaeria</Emphasis> sp<Emphasis Type="Italic">.</Emphasis> F00741

A new 3,4-dihydroisocoumarin, named botryoisocoumarin A (1), was obtained from the fermentation culture of Botryosphaeria sp. F00741, together with two known ones, 3,8-dihydroxy-3-methylisochroman-1-one (2) and 4,8-dihydroxy-3-methylisochroman-1-one (3). Their structures were elucidated by spectroscopic analyses, including 1D and 2D NMR experiments and ESI mass spectrometry, and by comparison with those reported. Compound 1 was evaluated for its antitumor and antimicrobial activities in vitro.     

Benzophenanthridine alkaloids from the roots of Thalictrum microgynum Lecoy.ex Oliv

A new benzophenanthridine alkaloid, 2,3,9-trimethoxy-7,8-methylenedioxy-5-methylbenzo[c]-6(5H) phenanthridone (2) and a benzophenanthridine alkaloid first found from natural sources, 2,3-dimethoxy-7,8- methylenedioxy-5-methylbenzo[c]-6(5H)- phenanthridone (1) together with two known benzophenanthridine alkaloids, Dihydrosanguinarine (3) and Dihydrochelilutine (4) were isolated from the roots of Thalictrum microgynum Lecoy.ex Oliv. The structures of 1 and 2 were elucidated using various spectroscopic techniques including HRESIMS and 1?D and 2?D NMR. Antibacterial activity of these compounds were tested. Compound 1, 3 and 4 showed antibacterial activity against Staphylococcus aureus with MIC values of 50, 100, 25?μg/mL, respectively.     

Chemistry and cytotoxic activities of polyketides produced by the mangrove endophytic fungus <Emphasis Type="Italic">Phomopsis</Emphasis> SP. ZSU-H76

A new polyketide, 2-(7′-hydroxyoxooctyl)-3-hydroxy-5-methoxybenzeneacetic acid ethyl ester (1), together with three known compounds dothiorelone A (2), B (3), and C (4) were isolated from the mangrove endophytic fungus Phomopsis sp. ZSU-H76 obtained from the South China Sea. Their structures were elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopic techniques. Primary bioassays showed that 1 exhibited cytotoxicity against HEp-2 and HepG2 cells with IC₅₀ values of 25 and 30 μg/mL, respectively.     

New compound from Euphorbia alatavica Boiss

One new compound alatavinol (1), together with five known compounds, kaempferol (2), quercetin (3), laricircsinol (4), secoisolariciresinol (5) and loliolide (6) were isolated from the whole plant of Euphorbia alatavica Boiss. Those compounds were isolated and purified by various column chromatographic methods and their structures were elucidated by spectroscopic (1D, 2D NMR, and HR-MS) chemical analyses. All compounds were isolated for the first time from E. alatavica Boiss, and biochemical pathway of the new compound has been hypothesized. Furthermore, these compounds were evaluated for antioxidant properties based on the DPPH radical scavenging activities. Results showed that IC₅₀ values of compounds 1, 3, 4, 5 and 6 were 25.69, 1.88, 2.87, 11.55 and 17.81 μg/mL, respectively, as compared to the control ascorbic acid (5.34 μg/mL).     

Cytotoxic cholic acid type sterones from a marine soft coral <Emphasis Type="Italic">Paraminabea</Emphasis> sp.

Chemical investigation of an Okinawan marine soft coral resulted in the isolation of one new compound (1) and five known cholic acid type keto-steroids 2–6 possessing enone or dienone A-rings and desmosterol (7). The structures of all compounds were elucidated from spectral data, mainly by 1D and 2D NMR techniques, mass spectra, comparison of NMR data with those of reported compounds, and by chemical transformations. Compounds 1–7 showed potent cytotoxic activity.     

A new sulphated flavone and other phytoconstituents from the leaves of Tetracera indica Merr. and their alpha-glucosidase inhibitory activity

The bioactivity guided fractionation of Tetracera indica leaves crude ethanolic extract has afforded the isolation and characterization of six compounds including a new natural product viz., 5,7-dihydroxyflavone-O-8-sulphate (1) and five known flavonoids (2–6). The structures of the compounds were elucidated using 1D and 2D NMR and HRESIMS spectroscopic analyses. All the isolated compounds were evaluated for their in vitro inhibitory activity against alpha-glucosidase. Compound 1, 5 and 6 showed strong alpha-glucosidase inhibitory activity, 3 and 4 displayed weak activity while compound 2 was inactive. The interactions of the active compounds with alpha-glucosidase were further investigated using molecular docking to confirm their antidiabetic potential.     

Two new dimeric naphthoquinones with neuraminidase inhibitory activity from Lithospermum erythrorhizon

The crude methanol extract of roots of Lithospermum erythrorhizon was subjected to successive chromatographic fractionation which afforded two new dimeric naphthoquinone derivatives shikometabolin E (2) and shikometabolin F (3) as well as one known compound shikometabolin A (1). The structures of compounds 1–3 were elucidated by using UV, MS, 1D and 2D NMR spectroscopic analysis. The two new dimeric naphthoquinone derivatives showed significant neuraminidase inhibitory activities.