[Show abstract][Hide abstract] ABSTRACT: Seven new (1-7) and three known (8-10) abietane diterpenoids were isolated from the methanolic extract of the aerial parts of Isodon lophanthoides var. graciliflorus (Lamiaceae), a folk Chinese medicine and an herb for functional beverages. They were identified as 16-acetoxylsugiol (1), graciliflorin E (2), graciliflorin F (3), 15-O-methylgraciliflorin F (4), 15-hydroxy-20-deoxocarnosol (5), 3β-hydroxysempervirol (6), 15-hydroxy-1-oxosalvibretol (7), abieta-8,11,13-triene-14,19-diol (8), 6,12,15-trihydroxy-5,8,11,13-abietatetraen-7-one (9), and 3α-hinokiol (10) based on the spectroscopic data including COSY (correlated spectroscopy), HMBC (heteronuclear multiple bond correlation), and HR-ESI-MS (high-resolution electrospray ionization mass spectrometry). All the compounds except 10 were obtained from I. lophanthoides for the first time. Compounds 1, 2, 5, 6, 8, and 9 exhibited in vitro cytotoxicity against A549 (human lung adenocarcinoma), MCF-7 (human breast adenocarcinoma), and HeLa (human cervical carcinoma) cell lines with the IC(50) values of 1.79-52.67μM.
[Show abstract][Hide abstract] ABSTRACT: The allelopathic effects of different parts of the plant Xanthium italicum Moretti were evaluated by conducting bioassays against two dicot plants, amaranth (Amaranthus mangostanus L.) and lettuce (Lectuca sativa L.), and two monocot plants, wheat (Triticum aestivum Linn) and ryegrass (Lolium multiforum). Leaf and fruit extract possessed the strongest biological activity, killing all seeds of four test species at 0.05 g/mL concentration. Fruits were chosen for further investigation because of their high biomass. This led to the isolation and identification of a phytotoxin-Xanthinosin-a known sesquiterpene lactone. Xanthinosin significantly affected seedling growth of all test species at 160 µM concentration. Cultivating seeds in 800 μM xanthinosin solution resulted in a great decrease in seedling growth of all test species, especially for the two dicot plants, amaranth and lettuce, whose root length was inhibited by 78% and 89%, respectively. By comparison, the numbers were 69% lower for wheat, and 66% for ryegrass, two monocot plants. When treated with 4 mM xanthinosin solution, seed germination of all test plants was almost completely inhibited. The possibility of utilizing xanthinosin as an eco-friendly herbicide was discussed.
[Show abstract][Hide abstract] ABSTRACT: A new natural product named longanlactone was isolated from Dimocarpus longan Lour. seeds. Its structure was determined as 3-(2-acetyl-1H--pyrrol-1-yl)-5-(prop-2-yn-1-yl)dihydrofuran-2(3H)-one by spectroscopic methods and HRESIMS.
[Show abstract][Hide abstract] ABSTRACT: Two new quinazoline alkaloids, 2-(2-carboxyethyl)-8-hydroxyquinazolin-4(3H)-one (1) and 2-(2-carboxyethyl)6-hydroxyquinazolin-4(3H)-one (2), along with the previously synthesized 2-(4-hydroxyphenyl)quinazolin4(3H)-one (3), were isolated from the solid cultures of Streptomyces michiganensis strain SC0642. Their structures were elucidated by spectroscopic methods.
Full-text · Article · Nov 2012 · Chemistry of Natural Compounds
[Show abstract][Hide abstract] ABSTRACT: Three glycosidic acids, turpethic acids A-C, and two intact resin glycosides, turpethosides A and B, all having a common pentasaccharide moiety and 12-hydroxy fatty acid aglycones of different chain lengths, were obtained from the aerial parts of Operculina turpethum. Their structures were elucidated by spectroscopic analyses and chemical correlations. The aglycones were characterized as 12-hydroxypentadecanoic acid in two compounds, 12-hydroxyhexadecanoic acid in two other components, and 12-hydroxyheptadecanoic acid in the fifth compound, which were all confirmed by synthesis. The absolute configurations of these aglycones were all established as S by Mosher's method. These compounds represent the first examples of resin glycosides with a monohydroxylated 12-hydroxy fatty acid as an aglycone, and one compound is the first described resin glycoside having a hydroxylated C(17) fatty acid as its aglycone.
[Show abstract][Hide abstract] ABSTRACT: Three new β-resorcylic acid lactones (RALs), paecilomycins G–I (1–3), and eight known compounds, aigialomycins B–D (4–6), 1′,2′-epoxy aigialomycin D (7), zearalenone (8), 7′-dehydrozearalenone (9), and trans-7′,8′-dehydrozearalenol (10), antibiotic LL-Z1640-1 (11), were isolated from the mycelial solid culture of Paecilomyces sp. SC0924. Their structures were established by spectroscopic methods and chemical means. In an assessment of antifungal activity by the well plate diffusion method, five known RALs, 4–7 and 11 showed weak activities against Peronophythora litchii
Full-text · Article · Jun 2012 · Chinese Journal of Chemistry
[Show abstract][Hide abstract] ABSTRACT: Twenty-two β-resorcylic acid lactones (RALs) were evaluated for cytotoxicity against human breast cancer cells to find their structure-activity relationship (SAR). Monocillin II, a trans-enone RAL without epoxy and conjugated dienone, was found to have higher activity in inhibiting tumor cell growth in both in vitro experiment and in vivo nude xenografted mice model than its analogue radicicol, an anticancer lead compound. We demonstrated for the first time that monocillin II could arrest breast cancer cell cycle in G1 phase, which might partially be the result of its inhibition effect on the phosphorylation of the Thr160 residue of cyclin dependent kinase 2 (CDK2), a key enzyme in cell-cycle regulation. Moreover, monocillin II exhibited inhibition of heat shock protein 90 (Hsp90) and depleted its target proteins, Raf-1 and A-Raf, which are involved in Ras/Raf/MEK/ERK mitogen-activated protein kinase (MAPK) pathway. Remarkably, we found that monocillin II could inhibit activation of MAPKs including ERK, JNK and p38, which might be involved in the inactivation of CDK2. These results suggest that monocillin II has potential therapeutic benefits in breast cancer prevention and intervention.
[Show abstract][Hide abstract] ABSTRACT: An activity-directed fractionation and purification process was used to isolate antioxidant components from cassava stems produced in Hainan. The ethyl acetate and n-butanol fractions showed greater DPPH˙and ABTS·+ scavenging activities than other fractions. The ethyl acetate fraction was subjected to column chromatography, to yield ten phenolic compounds: Coniferaldehyde (1), isovanillin (2), 6-deoxyjacareubin (3), scopoletin (4), syringaldehyde (5), pinoresinol (6), p-coumaric acid (7), ficusol (8), balanophonin (9) and ethamivan (10), which possess significant antioxidant activities. The relative order of DPPH· scavenging capacity for these compounds was ascorbic acid (reference) > 6 > 1 > 8 > 10 > 9 > 3 > 4 > 7 > 5 > 2, and that of ABTS·+ scavenging capacity was 5 > 7 > 1 > 10 > 4 > 6 > 8 > 2 > Trolox (reference compound) > 3 > 9. The results showed that these phenolic compounds contributed to the antioxidant activity of cassava.
[Show abstract][Hide abstract] ABSTRACT: Four new dammarane-type saponins, operculinosides A-D (1-4), were isolated from the aerial parts of Operculina turpethum, of which 1 and 2 are the first two dammarane-type triterpenoids having an oxymethyl group at C-24. Their structures were determined by spectroscopic analysis and acid hydrolysis. The absolute configuration of operculinoside A (1) was confirmed by X-ray crystallography. Compounds 1 and 3 showed significant protective activities against d-galactosamine-induced toxicity in L-02 human hepatic cells.
Preview · Article · Aug 2011 · Journal of Natural Products
[Show abstract][Hide abstract] ABSTRACT: 3-Hydroxy-3-methylglutaryl coenzyme A reductase (class II HMGR) could serve as a potential target to discover drugs fighting against the invasive diseases originated from Streptococcus pneumoniae, one of the major causes of bacterial disease in human. However, no strongly effective inhibitors of class II HMGR have been found so far. In the present study, for the first time, four annonaceous acetogenins (ACGs) were explored for the inhibition on S. pneumoniae HMGR. The results showed that the ACGs had higher inhibitory activities against S. pneumoniae HMGR with K(i) values in the range of 6.45-20.49 μM than the statin drug lovastatin (K(i)=116.25 μM), a classical inhibitor of class I HMGR. Then, three-dimensional modeling and docking simulations analyzed the possible binding mode of ACGs to S. pneumoniae HMGR and suggested a kind of novel structural and binding mode for designing promising inhibitor candidates of the targeted enzyme S. pneumoniae II HMGR.
No preview · Article · Jun 2011 · Bioorganic & medicinal chemistry
[Show abstract][Hide abstract] ABSTRACT: 3,12-Dihydroxy-cis-3,4-methylenedodecanoic acid 3-O-β-d-glucopyranoside, trivially named litchioside C (1), the first cyclopropyl-containing fatty acid glycoside, was isolated along with three previously uncharacterized galactosylacylglycerols from the seeds of Litchi chinensis. Its structure was established on the basis of spectroscopic analysis including HRESIMS and 2D NMR spectra. Its antioxidant and antibacterial activities were evaluated and its biogenetic pathway was discussed.
[Show abstract][Hide abstract] ABSTRACT: The first stilbene possessing a γ-aminobutyric acid lactam function, artocarpene (1), and a new flavanone, 2-hydroxynaringenin 4'-O-β-d-glucopyranoside (2), were isolated from the stems of Artocarpus nitidus subsp. lingnanensis along with four known compounds, 2-hydroxynaringenin (3), oxyresveratrol (4), 3,4',5-trihydroxy-3'-prenylstilbene (5) and norartocarpetin (6). Their structures were elucidated on the basis of spectroscopic data. Compounds 1 exhibited weak antioxidant activity and 2 displayed weak cytotoxicity against human lung cancer A549 cell line.
[Show abstract][Hide abstract] ABSTRACT: Seven flavonoid glycosides, including one new (1) and five previously uncharacterized (3-7), were obtained from the seeds of lychee ( Litchi chinensis Sonn. cv. Heiye) by means of repetitive column chromatography and high-performance liquid chromatography (HPLC) preparation. They were identified as litchioside D (1), (-)-pinocembrin 7-O-neohesperidoside (2), (-)-pinocembrin 7-O-rutinoside (3), taxifolin 4'-O-β-d-glucopyranoside (4), kaempferol 7-O-neohesperidoside (5), tamarixetin 3-O-rutinoside (6), and phlorizin (7) on the basis of spectroscopic analysis and comparison of their data to the values reported in the literatures. Among them, compounds 1, 4, and 5 showed in vitro antitumor activity against A549, LAC, Hep-G2, and HeLa cell lines in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay.
Full-text · Article · Feb 2011 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: Two new monoterpenoid indole alkaloid derivatives, turpiniside (1) and 11-methoxyjavaniside (2), along with the known alkaloids, vincosamide (3), (3 R)-pumiloside (4), and paratunamide C (5), were isolated from the leaves of Turpinia arguta (Lindl.) Seem. Their structures were determined on the basis of spectroscopic data. Compounds 1 and 3-5 were found to effect relaxation of the supercoiled pBR322 plasmid DNA in the presence of Cu²+.
[Show abstract][Hide abstract] ABSTRACT: A new isocoumarin, 7-hydroxyl-4-methyl isocoumarine (1), together with three known monoterpenes, (3R, 4R, 6S)-3, 6-dihydroxy-1-menthene (2), (+)-(1R, 3S, 4R, 6S)-6-hydroxymenthol (3) and 4-isopropyl-1-methylcyclohex-2-ene-1, 6-diol (4), was isolated from the methanol extract of Brickellia rosmarinifolia. The structures were determined by spectroscopic means. Compounds 1, 2, 3 and 4 showed antifungal activities against Colletotrichum musae and Peronophythora litchii in vitro.
[Show abstract][Hide abstract] ABSTRACT: Two new sesquiterpene glucosides, litchiosides A (1) and B (2), were obtained along with pumilaside A (3) and funingensin A (4) from lychee (Litchi chinensis Sonn.) seed. Their structures were elucidated on the basis of spectroscopic and chemical evidence. The in vitro antitumour activity of compounds 1–4 against A549, LAC, Hela, and Hep-G2 cell lines was determined using the MTT colourimetric assay. Pumilaside A (3) exhibited significant activity against all the tested cell lines with IC50 values of 0.012–6.29 μM, and funingensin A (4) showed moderate activity against Hep-G2 cells (IC50 = 39.27 μM), while litchiosides A (1) and B (2) were found to be inactive.
[Show abstract][Hide abstract] ABSTRACT: Two new A-type trimeric proanthocyanidins with two doubly bonded interflavanoid linkages, litchitannin A1 [epicatechin-(2β→O→7,4β→6)-epicatechin-(2β→O→7,4β→8)-catechin] (1) and litchitannin A2 [epicatechin-(2β→O→7,4β→6)-epicatechin-(2β→O→7,4β→6)-epicatechin] (2), were isolated from lychee (Litchi chinensis Sonn. cv. Heiye) seeds together with aesculitannin A (3), epicatechin-(2β→O→7,4β→8)-epiafzelechin-(4α→8)-epicatechin (4), proanthocyanidin A1 (5), proanthocyanidin A2 (6), proanthocyanidin A6 (7), epicatechin-(7,8-bc)-4β-(4-hydroxyphenyl)-dihydro-2(3H)-pyranone (8), and epicatechin (9). Their structures were elucidated on the basis of spectroscopic and chemical evidence. It is the first time that compounds 1-4, 7, and 8 have been reported in this species. Compounds 1-9 showed more potent antioxidant activity than L-ascorbic acid with ferric reducing antioxidant power (FRAP) values of 3.71-24.18 mmol/g and IC50 values of 5.25-20.07 μM toward DPPH radicals. Moreover, litchitannin A2 (2) was found to exhibit in vitro antiviral activity against coxsackie virus B3 (CVB3) and compounds 3 and 6 displayed antiherpes simplex virus 1 (HSV-1) activity.
Full-text · Article · Oct 2010 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: Sarcandracoumarin (1), the first coumarin having a 1-phenylethyl substituent at the C-3 position, was isolated along with eleven known phenolic compounds from the water extract of Sarcandra glabra. Its structure was elucidated on the basis of spectroscopic data. Compound 1 exhibited moderate or weak cytotoxicity against several tumor cell lines.