Pentasaccharide glycosides from the tubers of sweet potato (Ipomoea batatas)

Sweet potato ( Ipomoea batatas) has been used as food and herb in many countries. In this research on the active constituents of sweet potato, nine compounds were isolated and identified, including seven new resin glycosides, batatosides A-G (1- 7), along with two known compounds, batatinoside I ( 8) and simonin IV ( 9). The structures of 1- 9 have been established by a combination of spectroscopic and chemical methods. The major characteristics of the new compounds are the presence of three different substituents. The absolute configuration of aglycones was established as S by Mosher's method. Batatoside E ( 5) showed weak cytotoxic activity against Hep-2 cells.     

Design, synthesis, and fungicidal activity of macrolactones and macrolactams with a sulfonamide side chain

Four series of novel macrolactones and macrolactams12-alkylsulfonamido-1,15-pentadecanlactones ( 5), 12-alkylsulfonamido-15-methyl-1,15-pentadecanlactones ( 6), 12-alkylsulfonamido-1,15-pentadecanlactams ( 7), and N-(alkylsulfonamidoethyl)-1,12-dodecanlactams ( 8)were designed and synthesized from readily available 2-nitrocyclododecanone or cyclododecanone. Their structures were confirmed by (1)H NMR, IR, and elemental analysis. The bioassay showed that these compounds displayed fair to excellent fungicidal activity against Rhizoctonia solani Kuhn and have a gradual increase of fungicidal activity in the order of 6, 7, 8, and 5. Among them, compounds 5a, 5b, and 5c displayed excellent fungicidal activity against R. solani comparable with the commercial fungicide carbendazim. Above results illustrated that the rule on the relationship between the activity and hydrogen-bonding, namely the macrocyclic compounds with a hydrogen-bonding acceptor and a hydrogen-bonding donor on the ring and having a three methylenes distance between two polarizable groups have the best fungicidal activity against R. solani, has a general suitability to the macrocyclic compounds, and pesticide molecules may combine with a target enzyme by hydrogen-bonding. The facts, which compound 6 has a much lower fungicidal activity against R. solani than compound 5 but their difference in chemical structure is only that there is a methyl group on the C15 for compound 6 and none but hydrogen atom on the C15 for compound 5, indicated that a methyl group plays an inhibitory role to the fungicidal activity. It suggests that the existence of a methyl group with a great volume between two polarizable groups would interfere in the interaction of pesticide molecules and the target enzyme.     

Insecticidal activity of penitrems,including penitrem G,a new member of the family isolated from Penicillium crustosum

Penitrem G (7), a new indole-diterpenoid compound, has been isolated together with the already known mycotoxins penitrems A-D (1-4) and F (6) from the mycelium of Penicillium crustosum Thom. The structure of penitrem G was established on the basis of spectroscopic data. In addition, paspaline (8), another indole-diterpenoid mycotoxin that has not been previously described in this fungus, was also isolated. These compounds were tested for insecticidal activity against the hemipteran Oncopeltus fasciatus Dallas and the dipteran Ceratitis capitata Wiedemann. Penitrems A-D and F showed convulsive and insecticidal activities against both insect species. In addition, important reductions in the fecundity and fertility of the surviving C. capitata females were observed. In contrast, penitrem G and paspaline did not show any kind of activity. Mortality data and sublethal effects of the treatments have allowed preliminary structure-activity relationships to be proposed.     

Insect antifeedant flavonoids from Gnaphalium affine D. Don

The antifeedant flavonoids, 5-hydroxy-3,6,7,8,4'-pentamethoxyflavone (1), 5-hydroxy-3,6,7,8-tetramethoxyflavone (2), 5,6-dihydroxy-3, 7-dimethoxyflavone (3), and 4,4',6'-trihydroxy-2'-methoxychalcone (4), have been isolated from cudweed Gnaphalium affine D. Don (Compositae). Four natural flavonoids showed insect antifeedant activity against the common cutworm (Spodoptera litura F.). These flavonoids were detected in small amounts in the plant by HPLC analysis, but these natural compounds had strong antifeedant activity against the common cutworm. On the other hand, 4 was detected in a large amount in the plant, but this compound had only a slight activity. Therefore, these natural compounds were regarded as one of the plant's defensive systems against phytophagous insects along with the woolly plant surface. As for the structure-activity relationship, it is an advantage for antifeedant activity to have no oxy-substituents on the B-ring of the flavonoid but have an ether linkage such as a pyran in the chemical structure.     

Sterol ferulates, sterols, and 5-alk(en)ylresorcinols from wheat, rye, and corn bran oils and their inhibitory effects on Epstein-Barr virus activation

Sterol ferulate, free sterol, and 5-alk(en)ylresorcinol constituents of wheat, rye, and corn bran oils were studied. Among the sterol ferulates, one novel compound, 24-methylenecholestanol ferulate (7), along with six known compounds, namely, 24-methylcholestanol ferulate (1), 24-methylcholesterol ferulate (2), 2-methyllathosterol ferulate (3), stigmastanol ferulate (4), sitosterol ferulate (5), and schottenol ferulate (6), were isolated and characterized. Five known free sterols, namely, 24-methylcholesterol (8), stigmastanol (9), sitosterol (10), schottenol (11), and stigmasterol (12), were isolated and identified. 5-Alk(en)ylresorcinols were found in wheat and rye bran oils but not in corn bran oil. Of these, one new compound, 5-n-(2'-oxo-14'-Z-heneicosenyl) resorcinol (19), and seven known compounds, namely, 5-n-heptadecyl- (13), 5-n-nonadecyl- (14), 5-n-heneicosyl- (15), 5-n-tricosyl- (16), 5-n-pentacosyl- (17), 5-n-(14'-Z-nonadecenyl)- (18), and 5-n-(2'-oxoheneicosyl)resorcinols (20), were isolated and characterized. These compounds were evaluated with respect to their inhibitory effects on the induction of Epstein-Barr virus early antigen (EBV-EA) by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells, which is known to be a primary screening test for antitumor promoters. Four compounds, 1, 2, 4, and 11, showed potent inhibitory effects on EBV-EA induction.     

Namibian chewing stick, Diospyros lycioides, contains antibacterial compounds against oral pathogens

The twigs of Diospyros lycioides, a plant commonly known as "muthala", are frequently used as chewing sticks for the cleaning of teeth by rural and urban people in Namibia. Preliminary studies showed that a methanol extract of D. lycioides inhibited growth of selected oral pathogens. Subsequent bioassay-guided fractionation led to the isolation of four novel bioactive naphthalene glycosides, diospyrosides A, B, C, and D (1-4), and two known bioactive naphthoquinones, juglone (5) and 7-methyljuglone (6). The structures of the new compounds were elucidated using spectroscopic techniques including 1D and 2D NMR. These compounds inhibited the growth of oral cariogenic bacteria (Streptococcus mutans and Streptococcus sanguis) and periodontal pathogens (Porphyromonas gingivalis and Prevotella intermedia) at minimum inhibitory concentrations ranging from 0.019 to 1.25 mg/mL. Juglone exhibited the strongest inhibitory activity among these compounds.     

Antifungal activity of new 1,3,4-oxadiazolo[3,2-a]-s-triazine-5, 7-diones and their 5-thioxo-7-ones

N(1)- and N(3)-(4-fluorophenyl) ureas (III a-e) were cyclocondensed with ethyl chloroformate and CS(2)/KOH to yield 2-aryl-6-(4-fluorophenyl)-1,3,4-oxadiazolo[3,2-a]-s-triazine-5, 7-diones (IVa-e) and their 5-thioxo-7-ones (Va-e), respectively. The compounds III-V(a-e) have been compared with Dithane M-45 for their fungitoxic action against A. niger and F. oxyporum, and the results have been correlated with the structural features of the tested compounds.     

Isolation and characterization of rosmarinic acid oligomers in Celastrus hindsii Benth leaves and their antioxidative activity

Antioxidative compounds were isolated from the 50% methanol extract of dried leaves of Celastrus hindsii. Eight phenolic compounds (1-8) were finally obtained by reversed-phase high-performance liquid chromatography, and their structures were elucidated by nuclear magnetic resonance spectrometry and mass spectrometry analyses. They were the five known compounds, rutin (1), kaempferol 3-rutinoside (2), rosmarinic acid (3), lithospermic acid (4), and lithospermic acid B (6), and three novel oligomers of rosmarinic acid, a dimer (5) and two trimers (7 and 8). The major components in the extract were rosmarinic acid (3) and lithospermic acid B (6). These phenolic compounds were shown to have antioxidative activities against the autoxidation of methyl linoleate in bulk phase and the radical-initiated peroxidation of soybean phosphatidylcholine in liposomes. In the liposomal peroxidation, the number of phenolic hydroxyl group in each molecule was correlated with the effectiveness of antioxidative activity.     

Natural fungicides from Ruta graveolens L. leaves,including a new quinolone alkaloid

Bioassay-directed isolation of antifungal compounds from an ethyl acetate extract of Ruta graveolens leaves yielded two furanocoumarins, one quinoline alkaloid, and four quinolone alkaloids, including a novel compound, 1-methyl-2-[6'-(3' ',4' '-methylenedioxyphenyl)hexyl]-4-quinolone. The (1)H and (13)C NMR assignments of the new compound are reported. Antifungal activities of the isolated compounds, together with 7-hydroxycoumarin, 4-hydroxycoumarin, and 7-methoxycoumarin, which are known to occur in Rutaceae species, were evaluated by bioautography and microbioassay. Four of the alkaloids had moderate activity against Colletotrichum species, including a benomyl-resistant C. acutatum. These compounds and the furanocoumarins 5- and 8-methoxypsoralen had moderate activity against Fusarium oxysporum. The novel quinolone alkaloid was highly active against Botrytis cinerea. Phomopsis species were much more sensitive to most of the compounds, with P. viticola being highly sensitive to all of the compounds.     

Cytotoxic phenylpropanoids from carrot

Carrot is widely used as a foodstuff. The active components such as beta-carotene and panaxynol have been studied by many researchers. In this investigation of nonpolar active components from carrot, a new phenylpropanoid, epilaserine oxide ( 3), was isolated along with six known compounds, laserine ( 1), 2-epilaserine ( 2), panaxynol ( 4), ginsenoyne K ( 5), (8 E)-1,8-heptadecadiene-4,6-diyne-3,10-diol ( 6), and vaginatin ( 7). Their structures were deduced on the basis of spectroscopic methods. Significant cytotoxicity of 2-epilaserine against HL-60 cells was observed, which implied that phenylpropanoids were cytotoxic compounds in carrot. Laserine and 2-epilaserine in carrots from diverse locations in China were quantified by HPLC.     

Batatinosides II-VI, acylated lipooligosaccharides from the resin glycosides of sweet potato

Sweet potato ( Ipomoea batatas) belongs to the Convolvulaceae (morning glory family) and is native to Mexico and Central America. Its edible tuberous roots have been much appreciated since pre-Hispanic times in Mesoamerica and now play an important role as a basic diet staple and a medicinal plant worldwide. The hexane-soluble extract from roots, through preparative-scale recycling HPLC, yielded five new lipophilic oligosaccharides of jalapinolic acid, batatinosides II-VI ( 1- 5), as well as the known pescapreins I ( 6) and VII ( 7) and murucoidin I ( 8), which are part of the purgative resin glycoside mixture. NMR spectroscopy and FAB mass spectrometry were used to characterize their structures. Compounds 1 and 2 are tetraglycosidic lactones of operculinic acid C. The pentasaccharide structures for compounds 3 and 4 were confirmed to be macrolactones of simonic acid B, and that characterized for 5 was derived from operculinic acid A. The lactonization site of the aglycone was placed at C-3 of the second saccharide unit in all compounds except 4, where it was placed at C-2. All compounds contain an esterifying residue that is composed of a long-chain fatty acid, n-decanoic acid (capric) or n-dodecanoic acid (lauric). In compound 3, an additional short-chain fatty acid, (2 S)-methylbutyric acid, was also identified.     

Structural analysis of a novel antimutagenic compound, 4-Hydroxypanduratin A, and the antimutagenic activity of flavonoids in a Thai spice, fingerroot (Boesenbergia pandurata Schult.) against mutagenic heterocyclic amines.

Six compounds were isolated from fresh rhizomes of fingerroot (Boesenbergia pandurata Schult.) as strong antimutagens toward 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) in Salmonella typhimurium TA98. These compounds were 2',4',6'-trihydroxychalcone (pinocembrin chalcone; 1), 2',4'-dihydroxy-6'-methoxychalcone (cardamonin; 2), 5,7-dihydroxyflavanone (pinocembrin; 3), 5-hydroxy-7-methoxyflavanone (pinostrobin; 4), (2,4,6-trihydroxyphenyl)-[3'-methyl-2'-(3' '-methylbut-2' '-enyl)-6'-phenylcyclohex-3'-enyl]methanone (5), and (2,6-dihydroxy-4-methoxyphenyl)-[3'-methyl-2'-(3' '-methylbut-2' '-enyl)-6'-phenylcyclohex-3'-enyl]methanone (panduratin A; 6). Compound 5 was a novel compound (tentatively termed 4-hydroxypanduratin A), and 1 was not previously reported in this plant, whereas 2-4 and 6 were known compounds. The antimutagenic IC(50) values of compounds 1-6 were 5.2 +/- 0.4, 5.9 +/- 0.7, 6.9 +/- 0.8, 5.3 +/- 1.0, 12.7 +/- 0.7, and 12.1 +/- 0.8 microM in the preincubation mixture, respectively. They also similarly inhibited the mutagenicity of 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). All of them strongly inhibited the N-hydroxylation of Trp-P-2. Thus, the antimutagenic effect of compounds 1-6 was mainly due to the inhibition of the first step of enzymatic activation of heterocyclic amines.     

Free radical scavenging and antioxidative activity of caffeic acid amide and ester analogues: structure-activity relationship.

The structure-activity relationships of synthetic caffeic acid amide and ester analogues as potential antioxidants and free radical scavengers have been investigated. The 2,2-diphenyl-1-picrylhydrazyl radical (DPPH.) scavenging activity of the test compounds was N-trans-caffeoyl-L-cysteine methyl ester (5) > N-trans-caffeoyldopamine (4) > N-trans-caffeoyltyramine (3) > N-trans-caffeoyl-beta-phenethylamine (2) > Trolox C (8) > caffeic acid phenethyl ester (1) > caffeic acid (6) > ferulic acid (7). This established that the radical scavenging activity of the compounds increased with increasing numbers of hydroxyl groups or catechol moieties and also with the presence of other hydrogen-donating groups (-NH, -SH). The antioxidative activity of the compounds was also investigated in an emulsified linoleic acid oxidation system accelerated by 2,2'-azobis(2-amidinopropane) dihydrochloride. The order was 1 > 2 > 4 > 3 > or = 5 > 6 > 8 > 7. Therefore, in the emulsion system, the antioxidative activity of the test compounds depends not only on the hydroxyl groups or catechol rings but also on the partition coefficient (log P) or hydrophobicity of the compounds. This supports the concept that hydrophobic antioxidants tend to exhibit better antioxidative activity in an emulsion system.     

Constituents of the leaves of Peucedanum japonicum Thunb. and their biological activity

In the course of our study on the isolation and structure determination of constituents in tropical plants, we focused on Peucedanum japonicum Thunb., belonging to the family Umbelliferae. In this study, a new C(13) norisoprenoid glucoside, (3S)-O-beta-d-glucopyranosyl-6-[3-oxo-(2S)-butenylidenyl]-1,1,5-trimethylcyclohexan-(5R)-ol (1), and two new phenylpropanoid glucosides, 3-(2-O-beta-d-glucopyranosyl-4-hydroxyphenyl)propanoic acid (3) and methyl 3-(2-O-beta-d-glucopyranosyl-4-hydroxyphenyl)propanoate (4), were isolated from the n-butanol soluble fraction of this plant's leaves, together with five known compounds. The structures of these compounds were determined on the basis of spectroscopic evidence. In addition, all isolated compounds were examined for scavenging activity against 1,1-diphenyl-2-picrylhydrazyl radical and inhibitory activity against mushroom tyrosinase. These results suggested that 2-(4-hydroxy-3-methoxyphenyl)propane-1,3-diol (7) and 3-O-beta-d-glucopyranosyl-2-(4-hydroxy-3-methoxyphenyl)propanol (8) showed an appreciable activity in both assay systems.     

Flavonoid constituents of Chorizanthe diffusa with potential cancer chemopreventive activity

An ethyl acetate-soluble extract of Chorizanthe diffusa was found to exhibit significant antioxidant activity, as judged by scavenging stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals and inhibition of 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced free radical formation with cultured HL-60 cells. Bioassay-directed fractionation of this extract using the DPPH antioxidant assay as a monitor led to the isolation of five structurally related flavonoids (1-5), including the novel compound 5,8,3',4',5'-pentahydroxy-3, 7-dimethoxyflavone (1). Isolates 1-5 demonstrated varying degrees of antioxidant or antimutagenic activity. Two of the compounds, 5,7,3', 4'-tetrahydroxy-3-methoxyflavone (2) and quercetin (4), were subsequently found to inhibit carcinogen-induced preneoplastic lesions in a mouse mammary organ culture model. Inhibitory activity of this type is known to correlate with cancer chemopreventive effects in full-term models of tumorigenesis.     

Lipoperoxidation and cyclooxygenases 1 and 2 inhibitory compounds from Iryanthera juruensis

Plants from Iryanthera genus have been traditionally used as food supplements by South American Indians. The MeOH extract of leaves of Iryanthera juruensis, one of the plants endemic to the Amazon region and consumed in Brazil, and the hexane extract from its seeds inhibited lipid peroxidation (LPO) and cyclooxygenase (COX-1 and -2)) enzymes in in vitro assays. Further analyses of these extracts yielded 5-deoxyflavones (1-5) from the leaf extract and sargachromenol (6), sargaquinoic acid (7), a novel juruenolic acid (8), omega-arylalkanoic acids (9a-c), and the lignan guaiacin (10) from the seed extract. Compounds 3-5 inhibited LPO by 86%, 77%, and 88% at 10 ppm, respectively, and compounds 6 and 9a-c showed inhibition at 76% and 78% at 100 ppm, respectively. However, compounds 7 and 8 were inactive and lignan 10 exhibited LPO inhibitory activity by 99% at 100 ppm compared to commercial antioxidants butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and vitamin E. The flavones 1-5 also inhibited COX-1 and -2 enzymes by 50-65% at 100 ppm. Compound 6 showed high but nonselective inhibition of COX-1 and COX-2 enzymes, when compared to aspirin and Celebrex, a nonsteroidal anti-inflammatory drug (NSAID). Compounds 7 and 10 inhibited COX-1 by 60% and 65% and COX-2 by 37% and 18%, respectively, whereas compounds 8 and 9a-c showed little or no activity against these enzymes.     

Isolation and identification of compounds responsible for antioxidant capacity of Euryale ferox seeds

Euryale ferox seed is consumed medicinally or for food in China. The present study revealed it to contain significant antioxidant activity, which may be associated with its medical applications as a proteinuria inhibitor of diabetic nephropathy. This study resulted in the identification of 3 new sesquineolignans, named euryalins A-C (1-3), and 16 known compounds, which were all first isolated from this plant apart from 5,7,4-trihydroxy-flavanone. The antioxidant potential of the partial isolates was evaluated using the DPPH radical scavenging assay and mesangial cellular assay. Compounds 2, rel-(2α,3β)-7-O-methylcedrusin (4), syringylglycerol-8-O-4-(sinapyl alcohol) ether (5), and (+)-syringaresinol (7) were found to be most active on DPPH assay, whereas compounds 2, 4, 7, (1R,2R,5R,6S)-2-(3,4-dimethoxyphenyl)-6-(3,4-dihydroxyphenyl)-3,7-dioxabicyclo[3.3.0]octane, and buddlenol E could significantly inhibit high glucose-stimulated reactive oxygen species production in mesangial cells. The results suggested that E. ferox seed could be considered as an excellent source of natural antioxidants and is useful in the prevention of diabetic nephropathy.     

Puerins A and B, two new 8-C substituted flavan-3-ols from Pu-er tea

Pu-er tea is a special treated fermented tea produced from crude green tea, which is prepared from the leaves of Camellia sinensis var. assamica. It is a traditional beverage having been used in China, particularly the southern areas, for a long time. Chemical investigation led to the identification of two new 8-C substituted flavan-3-ols, puerins A (1) and B (2), and two known cinchonain-type phenols, epicatechin-[7,8-bc]-4alpha-(4-hydroxyphenyl)-dihydro-2(3H)-pyranone (3) and cinchonain Ib (4), together with other seven known phenolic compounds, 2,2',6,6'-tetrahydroxydiphenyl (5), (-)-epicatechin-8-C-beta-d-glucopyranoside (6), (-)-epicatechin (EC) (7), (-)-epigallocatechin (EGC) (8), (+/-)-gallocatechin (GC) (9), gallic acid (10), and myricetin (11), in addition to caffeine (12). Their structures were determined by spectroscopic methods. The compounds 1-5, which might be formed in the postfermentative process of Pu-er tea, were isolated from tea and theaceous plants for the first time.     

Unusual lactones from Cananga odorata (Annonaceae).

Two lactone compounds have been isolated from the leaves and branches of ylang-ylang (Cananga odorata forma genuina Hook. f. et Thomson, Annonaceae). One was already known as isosiphonodin 1. The other, canangone 2, is a new terpenoid spirolactone with an unusual backbone. Its structure has been established as 6-hydroxy-1-oxo-2-oxaspiro[4.5]dec-7-ene-8-carbaldehyde by using 1-D and 2-D NMR.