Constituents of the Vietnamese medicinal plant Orthosiphon stamineus

From the MeOH extract of the aerial part of Vietnamese Orthosiphon stamineus, five new isopimarane-type diterpenes [orthosiphols F-J (1-5)] and two new diterpenes [staminols A (6) and B (7)] with a novel carbon-framework, to which we proposed the name "staminane", and three new highly-oxygenated staminane-type diterpenes [staminolactones A (8) and B (9) and norstaminol A (10)1 were isolated. Moreover, staminolactone A (8) is 8,14-secostaminane-type and staminolactone B (9) is 13,14-secostaminane-type, while norstaminol A (10) is 14-norstaminen-type. Together with these new diterpenes, sixteen known compounds were also isolated and identified to be: 7,3',4'-tri-O-methylluteolin (11), eupatorin (12), sinensetin (13), 5-hydroxy-6,7,3',4'-tetramethoxyflavone (14), salvigenin (15), ladanein (16), tetramethylscutellarein (17), 6-hydroxy-5,7,4'-trimethoxyflavone (18), vomifoliol (19), aurantiamide acetate (20), rosmarinic acid (21), caffeic acid (22), oleanolic acid (23), ursolic acid (24), betulinic acid (25), and beta-sitosterol (26). All the isolated compounds were tested for their cytotoxicity towards highly liver metastatic murine colon 26-L5 carcinoma cells, and the new diterpenes, except for 4, and flavonoids (11, 12, 16, 18) showed cytotoxicity with an ED50 value between 10 and 90 microg/ml.     

Antihepatitis B virus constituents of Solanum erianthum

Eleven compounds were isolated from the methanolic extract of the leaves of Solanum erianthum D. Don, including five alpha-linolenic acid analogs, alpha-linolenic acid (1), 13S-hydroxy-9(Z),11(E)-octadecadienoic acid (2), 9S-hydroxy-10(E),12(Z), 15(Z)-octadectrienoic acid (3), 9(Z),11(E)-octadecadienoic acid (4), and octadecanoic acid (5); two benzofuran-type lactones, loliolide (6) and dihydroactinidiolide (7); two steroidal alkaloids, solasonine (8) and solamargine (9); a flavonol glycoside, camelliaside C (10); and a flavone, 5-methoxy-(3,4"-dihydro-3",4"-diacetoxy)-2",2'-dimethylpyrano-(7,8:5",6")-flavone (11). Among these isolated compounds, 9 showed the most potent activity against HBsAg, with an IC50 of 1.57 microM, followed by 8 (IC50 is 5.89 microM). In the testing against HBeAg, 11 was the only active compound with an IC50 of 36.11 microM. Compound 9 also revealed strong inhibition of DNA replication towards HBV and its IC50 was 2.17 microM. However, alpha-linolenic acid (1) showed a prominent selected index (SI), both in anti-HBsAg and inhibition of DNA replication with SI values of 7.75 and 7.18, respectively. This is the first report that unsaturated fatty acid 1, steroidal alkaloid glycoside 9 and flavone 11, all showed excellent activity against HBV. These results provide lead candidates in the development of anti-HBV drugs from natural sources.     

Cytotoxicity of constituents from Mexican propolis against a panel of six different cancer cell lines

The cytotoxicity of 39 compounds, including eighteen flavonoids (flavanones, 1-10; flavones, 11-17; flavanol, 18), sixteen phenolic acid derivatives (aromatic acids, 19-24; aldehyde, 25; esters, 26-34) and five glycerides (35-39), isolated from Mexican propolis, were evaluated against a panel of six different cancer cell lines; murine colon 26-L5 carcinoma, murine B16-BL6 melanoma, murine Lewis lung carcinoma, human lung A549 adenocarcinoma, human cervix HeLa adenocarcinoma and human HT-1080 fibrosarcoma. A phenylpropanoid-substituted flavanol, (2R,3S)-8-[4-phenylprop-2-en-1-one]-4',7-dihydroxy-3',5-dimethoxyflavan-3-ol (18), showed the most potent cytotoxicity against A549 cells (IC50, 6.2 microM) and HT-1080 cells (IC50, 3.9 microM), stronger than those of the clinically used anticancer drug, 5-fluorouracil (IC50, 7.5 microM and 5.4 microM, respectively). Based on the observed results, the structure-activity relationships are discussed.     

Three abietane diterpenes and two diterpenes incorporated sesquiterpenes from the bark of Cryptomeria japonica

Three new abietane diterpenes, sugikurojins D (1), E (2), and F (3), and two new abietanes which incorporate cadinane, sugikurojins G (4) and H (5) were isolated from the bark of Cryptomeria japonica. These structures were elucidated primarily by extensive NMR experiments. The structure of sugikurojin D (1) was deduced to be 6alpha-acetoxy-7beta,11-dihydroxy-12-methoxy-8,11,13-abietatriene. Sugikurojin E (2) was deduced to be 6alpha-acetoxy-7beta,12-dihydroxy-8,11,13-abietatriene. Sugikurojin F (3) was 7alpha-methoxy-8,13-abietadien-11,12-dione. Sugikurojins G (4) and H (5) had a unique skeleton incorporating an alpha-cadinol or a 1alpha-hydroxy-T-cadinol in ferruginol, respectively. Also obtained in this investigation were the known diterpenes (6-14). An antibacterial activity of ten among these against Staphylococcus aureus and Escherichia coli was inactive at the (MIC: 125 microg/ml) level. Meanwhile, in the cytotoxic activity against HL-60, compounds 4, 8, and 11 showed moderate (IC50: 4, 35.4; 8, 28.0; 11, 52.4 microM) though weak (IC50: 4, 100; 8, 80.8; 11, 100 microM) activity against HCT-15.     

A new labdane diterpene from the flowers of Solidago canadensis

A new labdane diterpene, 9alpha,16xi-dihydroxy-6-oxo-7,13-labdadien-15,16-olide (solicanolide, 1) and six known compounds identified as quercetin (2), 3-O-caffeoylquinic acid (3, neochlorogenic acid), 5-O-caffeoylquinic acid (4, chlorogenic acid), 4,5-di-O-caffeoylquinic acid (5), 3,5-di-O-caffeoylquinic acid (6) and 3,4-di-O-caffeoylquinic acid (7) were isolated from the flowers of Solidago canadensis. To our knowledge, compound 7 was isolated for the first time in S. canadensis. This work describes the isolation of compounds 1-7 and the structure elucidation of a new compound identified as compound 1. Solicanolide (1) showed cytotoxic activity against A549 (IC(50): 13+/-2 microM), DLD-1 (IC(50): 26+/-2 microM) and WS1 (IC(50): 17+/-1 microM) cell lines.     

Medicinal foodstuffs. XXXIV. Structures of new prenylchalcones and prenylflavanones with TNF-alpha and aminopeptidase N inhibitory activities from Boesenbergia rotunda

The methanolic extract from the rhizomes of Boesenbergia rotunda (Zingiberaceae) was found to show inhibitory effect on tumor necrosis factor-alpha (TNF-alpha)-induced cytotoxicity in L929 cells (IC(50)=6.1 microg/ml). By bioassay-guided separation, four new prenylcalcones, (+)-krachaizin A (1a), (-)-krachaizin A (1b), (+)-krachaizin B (2a), and (-)-krachaizin B (2b), and four new prenylflavanones, rotundaflavones Ia (3a), Ib (3b), IIa (4a), and IIb (4b), were isolated together with 18 known constituents (5a-7b and 8-19). The structures of eight new compounds were elucidated on the basis of physicochemical evidence. Among them, (+)-krachaizin B (2a), (-)-krachaizin B (2b), (+)-4-hydroxypanduratin A (6a), (-)-4-hydroxypanduratin A (6b), (+)-isopanduratin A (7a), (-)-isopanduratin A (7b), alpinetin (10), cardamonin (14), and 2,6-dihydroxy-4-methoxydihydrochalcone (15) significantly inhibited TNF-alpha-induced cytotoxicity in L929 cells at 10 microM. In addition, 2a, 2b, (+)-panduratins A (5a), (-)-panduratin A (5b), 6a, 7b, and geranyl-2,4-dihydroxy-6-phenylbenzoate (17) were found to show strong inhibitory effects on aminopeptidase N activity.     

Glutathione S-transferase inhibiting chemical constituents of Caesalpinia bonduc

Glutathione S-transferase inhibition assay-guided fractionations on the ethanolic extract of the bark of Caesalpinia bonduc resulted in the isolation of a new sterol, 17-hydroxy-campesta-4,6-dien-3-one (1) along with four known compounds, 13,14-seco-stigmasta-5,14-dien-3alpha-ol (2), 13,14-seco-stigmasta-9(11),14-dien-3alpha-ol (3), caesaldekarin J (4) and pipataline (5) as active constituents. Structures of compounds 1-5 were established on the basis of extensive NMR spectroscopic studies. The compounds (1-5) were isolated on the basis of their inhibitory activity against glutathione S-transferase, an enzyme that has been implicated in resistances during treatment of cancer and parasitic infections. Efforts to study structure-activity relationships of compounds 2 and 3 were also made by modifying their structures. The IC50 values of these compounds and their derivatives ranged from 57-380 microM and were compared to the inhibitory effects due to sodium taurocholate, an isoprene-derived GST inhibitor (IC50=398 microM). A plausible biosynthesis of 13,14-seco-steroids has also been proposed.     

Total synthesis of 12-methoxydihydrochelerythrine and anti-tumour activity of its quaternary base: toward an efficient synthetic route for 12-alkoxybenzo[c]phenanthridine bases via naphthoquinone monooxime from 2-benzofuranyl-1-tetralone derivative

A concise total synthesis of 12-methoxydihydrochelerythrine (6), isolated from Bocconia integrifolia, is described. The synthesis features an efficient route to a 12-alkoxybenzo[c]phenanthridine skeleton via naphthoquinone monooxime 11 as a key compound. Starting from 7-methoxy-2-methylbenzo[b]furan (9), 3-aryl-1-tetralone 10 was synthesised, followed by aromatisation to 3-aryl-1-naphthol 17. After oxidative cleavage of the furan ring, basic nitrosation of naphthol 22 gave the naphthoquinone 11. The benzo[c]phenanthridine skeleton was formed by reductive cyclisation of 11. Deoxygenation of the lactam moiety in 23 afforded nor-base 32 and methylation of 32 under reductive conditions gave the target dihydro base 6 (23 steps from benzofuran 9 in 10% overall yield). The corresponding quaternary base 7 showed moderate anti-tumour activity against cancer cell lines; on NCI-H460: IC50 4.5 microM and on MDA-MB-231: IC50 1.2 microM. Introduction of a methoxy group into the 12-position of the benzo[c]phenanthridine skeleton could cause enhanced activity against MDA-MB-231 by comparison of 7 with chelerythrine (35) (IC50 5.3 microM).     

Prolyl endopeptidase inhibitors from the underground part of Rhodiola sachalinensis

The methanolic extract of the underground part of Rhodiola sachalinensis was found to show inhibitory activity on prolyl endopeptidase (PEP, EC. 3.4.21.26), an enzyme that plays a role in the metabolism of proline-containing neuropeptidase which is recognized to be involved in learning and memory. From the MeOH extract, five new monoterpenoids named sachalinols A (24), B (25) and C (26) and sachalinosides A (23) and B (27) were isolated, together with twenty-two known compounds, gallic acid (1), trans-p-hydroxycinnamic acid (2), p-tyrosol (3), salidroside (4), 6n-O-galloylsalidroside (5), benzyl beta-D-glucopyranoside (6), 2-phenylethyl beta-D-glucopyranoside (7), trans-cinnamyl beta-D-glucopyranoside (8), rosarin (9), rhodiocyanoside A (10), lotaustralin (11), octyl beta-D-glucopyranoside (12), 1,2,3,6-tetra-O-galloyl-beta-D-glucose (13), 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (14), kaempferol (15), kaempferol 3-O-beta-D-xylofuranosyl(1-->2)-beta-D-glucopyranoside (16), kaempferol 3-O-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranoside (17), rhodionin (18), rhodiosin (19), (-)-epigallocatechin (20), 3-O-galloylepigallocatechin-(4-->8)-epigallocatechin 3-O-gallate (21) and rosiridin (22). Among these, nineteen compounds other than 3, 4 and 9 have been isolated for the first time from R. sachalinensis, and six (6, 8, 13, 16, 17, 20) are isolated from Rhodiola plants for the first time. Among them, six compounds (13, 14, 18, 19, 21, 22) showed noncompetitive inhibition against Flavobacterium PEP, with an IC50 of 0.025, 0.17, 22, 41, 0.44 and 84 microM, respectively.     

Terpenoids with a new skeleton and novel triterpenoids with anti-inflammatory effects from Garcinia subelliptica

Three novel phloroglucinol derivatives, garcinielliptones F (1), H (3), and I (4), and two novel terpenoids, garcinielliptones G (2) and J (5), with a new skeleton have been isolated from the seeds of Garcinia subelliptica. Their structures, including relative configurations, were elucidated by spectroscopic methods and computer-generated molecular modeling. Compound 1 showed potent inhibitory effects on the release of beta-glucuronidase and lysozyme from rat neutrophils that had been stimulated with formyl-Met-Leu-Phe (fMLP)/cytochalasin B (CB). This effect was concentration-dependent with IC(50) values of 26.9+/-2.6 and 20.0+/-1.3 microM, respectively. Compound 1 also showed a potent concentration-dependent inhibitory effect on superoxide anion generation in rat neutrophils stimulated with fMLP/CB, with an IC(50) value of 17.0+/-0.9 microM. Compound 4 showed a potent inhibitory effect on NO production in culture media of N9 cells in response to lipopolysaccharide (LPS)/interferon-gamma (IFN-gamma) in a concentration-dependent manner with an IC(50) value of 7.4+/-0.2 microM.     

Chemical constituents of the aerial parts of Scutellaria lateriflora and their alpha-glucosidase inhibitory activities

MeOH extracts of 37 herbs were tested in screening experiments for rat intestinal alpha-glucosidase. The MeOH extract of the aerial parts of Scutellaria lateriflora L. (Lamiaceae) significantly inhibited sucrase and maltase activities, using sucrose and maltase as the substrates. Enzyme inhibition guided-fractionation of the MeOH extract of S. lateriflora resulted in the isolation of a new diterpene glucoside, deacetylajugarin-IV 18-O-beta-D-glucopyranoside (1), along with 20 known phenolics (2-21). The structures of 1-21 were elucidated on the basis of MS and NMR data analyses. Baicalein (4) and baicalin (10), a glycoside of 4, showed moderate sucrase inhibitory activities at IC50 values of 14.9 and 36.3 microM, respectively, whereas luteolin (3), acteoside (16), leucosceptoside A (18), and isoacteoside (20) showed weak inhibitory activities at IC50 values of 811, 522, 727, and 443 microM, respectively. This is the first report on mammalian alpha-glucosidase inhibitory activities of S. lateriflora extract and identification of the constituents responsible for the activities. Apigenin (2), luteolin (3), 6-methoxyluteolin 4'-methyl ether (6), isoscutellarin 8-O-beta-D-glucuronide (7), luteolin 7-O-beta-D-glucuronide (9), wogonin 7-O-beta-D-glucuronide methyl ester (12), eriodictyol (13), naringenin (14), naringenin 7-O-beta-D-glucuronide (15), jionoside D (17), leucosceptoside A (18), and (+)-syringaresinol 4'-O-beta-D-glucopyranoside (21) were isolated from this plant for the first time. The inhibitory properties of S. lateriflora extract against alpha-glucosidase provide a prospect for its antidiabetic usage.     

Chemical constituents of Blumea balsamifera of Indonesia and their protein tyrosine phosphatase 1B inhibitory activity

A methanol extract of the leaves of Blumea balsamifera (L.) DC. (Asteraceae) afforded a new guaian-type sesquiterpene, epiblumeaene K (1), together with four known guaian-type sesquiterpenes (2-5), three known sesquiterpenes (6-8), and nine known flavonoids (9-17) by a combination of chromatography and preparative TLC techniques. Their structures were elucidated by extensive spectroscopic methods and comparison with the literature data. Among the isolated compounds, a known sesquiterpene, beta-caryophyllene 8R,9R-oxide (6), exhibited a significant PTP1B inhibitory activity in a dose-dependent manner, with an IC50 value of 25.8 microM (5.62 microg/mL).     

Anti-plasmodial and cholinesterase inhibiting activities of some constituents of Psorospermum glaberrimum

Glaberianthrone (1), a new bianthrone was isolated from the hexane extract of the stem bark of Psorospermum glaberrimum together with thirteen known compounds: 3-geranyloxyemodin anthrone (2), friedelan-3-one (3), 3-prenyloxyemodin anthrone (4), 3-geranyloxyemodin (5), 3-prenyloxyemodin (6), friedelan-3-ol (7), acetylvismione D (8), betulinic acid (9), 2-geranylemodin (10), bianthrone A2b (11), bianthrone 1a (12), emodin (13) and 2-prenylemodin (14). The structures of the isolated compounds were established by means of spectroscopic methods. The extracts and the isolated compounds were tested in vitro for their anti-plasmodial activity against Plasmodium falciparum (chloroquine resistant strain W2) and for their acetyl- and butyrylcholinesterase inhibitory properties. The n-hexane extract showed good anti-plasmodial activity against P. falciparum W2 strain, with IC(50) of 0.87 microg/ml. It also exhibited 65.5% and 98.2% of acetyl- and butyrylcholinesterase inhibition at 0.2 mg/ml, respectively. Compounds 2 and 8 showed the best potencies against P. falciparum W2 strain with IC(50) of 1.68 microM and 0.12 microM, (0.66 microg/ml and 0.054 microg/ml) respectively. All tested compounds showed good butyrylcholinesterase inhibition activities with compound 12 displaying the best potency (IC(50) 9.25+/-0.25 microM). All the tested compounds showed weak inhibitory activity against acetylcholinesterase.     

Studies on panax acetylenes: absolute structure of a new panax acetylene, and inhibitory effects of related acetylenes on the growth of L-1210 cells

A new Panax acetylene, 3-oxo-PQ-1 (1), was isolated from Panax quinquefolium. The absolute configurations of 3-oxo-PQ-1 (1) and PQ-1 (2) were determined to be (9R,10R) and (3R,9R,10R), respectively, by synthesizing 1 and 2 starting from D-(-)-diethyl tartrate, and by synthesizing their stereoisomers from L-(+)-diethyl tartrate. The growth inhibitory effects of Panax acetylenes (1-8) and their stereoisomers against leukemia cells were tested. Unnatural acetylenes having the (3S)-configuration (2, 5, 6, 7, 8; IC(50)=0.01-0.1 microg/ml) were found to be approximately ten times more potent than natural acetylenes (IC(50)=0.1-1.0 microg/ml) with the (3R)-configuration. Potency differences due to the configuration at C-9 and C-10 were unrelated to this stereochemistry. The C(14)-polyacetylenes, PQ-8 (4) and its isomer (IC(50)=1.0-10.0 microg/ml), were found to exhibit weaker cytotoxicity than the C(17)-polyacetylenes.     

Xanthine oxidase inhibitors from the heartwood of Vietnamese Caesalpinia sappan

From the MeOH extract of Vietnamese Caesalpinia sappan, a novel biogenetically exclusive benzindenopyran, with a new carbon framework, neoprotosappanin (1), and a new compound, protosappanin A dimethyl acetal (3), were isolated together with protosappanin E-2 (2), neosappanone A (4), and 13 previously reported phenolic compounds (5-17). Their structures were elucidated on the basis of spectroscopic data. Compounds 1-4, 7, 13, and 15-17 showed significant xanthine oxidase inhibitory activity in a concentration-dependent manner, and sappanchalcone (17) showed the most potent activity with an IC50 value of 3.9 microM, comparable to that of positive control allopurinol (IC50, 2.5 microM). The kinetic study of these inhibitors indicated that they are competitive inhibitors, the same as allopurinol, except for 1 and 16 which are noncompetitive inhibitors.     

Phelligridimer A, a highly oxygenated and unsaturated 26-membered macrocyclic metabolite with antioxidant activity from the fungus Phellinus igniarius

[structure: see text] A highly oxygenated and unsaturated 26-membered macrocyclic metabolite, phelligridimer A (1), has been isolated from the Chinese medicinal fungus Phellinus igniarius. Its structure was elucidated by spectroscopic methods. A possible biogenesis of 1 mediated by the fungal metabolite hispidin was postulated. Phelligridimer A showed antioxidant activity (IC50 of 10.2 microM) but was inactive to several human cancer cell lines (IC50 > 50 microM) and enzymes PTP1B (IC50 > 25 microM) and thrombin (IC50 > 10 microM).     

Novel and anti-inflammatory constituents of Garcinia subelliptica

Four novel phloroglucinol derivatives, garcinielliptones A (1), B (2), C (3), D (4), a novel triterpenoid, garcinielliptone E (5), and three known compounds were isolated from the seeds of Garcinia subelliptica. The structures, including relative configurations, were elucidated by means of spectroscopic data. Known compounds garsubellin A (6) and garcinielliptin oxide (7) showed potent inhibitory effects on the release of beta-glucuronidase, and beta-glucuronidase and histamine, respectively, from peritoneal mast cells stimulated with compound 48/80 in a concentration-dependent manner with IC(50) values of 15.6+/-2.5, and 18.2+/-3.6 and 20.0+/-2.7 microM, respectively. Compound 7 showed potent inhibitory effects on the release of beta-glucuronidase and lysozyme from neutrophils stimulated with formyl-Met-Leu-Phe(fMLP)/cytochalasin B (CB) in a concentration-dependent manner with IC(50) values of 15.7+/-3.0 and 23.9+/-3.2 microM, respectively. Compound 7 also showed potent inhibitory effect on superoxide formation from neutrophils stimulated with fMLP/CB also in a concentration-dependent manner with an IC(50) value of 17.9+/-1.5 microM.     

Phenolic constituents from the heartwood of Artocapus altilis and their tyrosinase inhibitory activity

From the MeOH extract of the heartwood of Artocapus altilis, thirteen phenolic compounds have been isolated, namely curcumin (1), desmethoxycurcumin (2), retrodihydrochalcone (3), apigenin (4), tangeretin (5), nobiletin (6), O-methyldehydrodieugenol (7), dehydrodieugenol (8), beta-hydroxypropiovanillone (9), p-coumaric acid (10), p-hydroxybenzaldehyde (11), vanillin (12), and vanillic acid (13). This is the first report on the presence of these compounds in the heartwood of A. altilis. Compounds 1, 2, and 10 showed more potent tyrosinase inhibitory activities, with IC50 values ranging from 2.3 to 42.0 microM, than the positive control kojic acid (IC50, 44.6 microM). The most active compound, p-coumaric acid (10) (IC50, 2.3 microM), was 22 times more active in tyrosinase inhibitory activity than kojic acid.