Cytotoxic Sesterterpenes from Thai Marine Sponge Hyrtios erectus.

Four sesterterpenes, erectusolides B, C, D, and seco-manoalide-25-methyl ether, two 2-furanone derivatives, erectusfuranones A and B, together with thirteen known sesterterpenes, (6Z)-neomanoalide-24-acetate, two diastereomers of 24-O-methylmanoalide, luffariolide B, manoalide, (6E)- and (6Z)-neomanoalide, seco-manoalide, scalarafuran, 12-acetylscalarolide, 12-epi-O-deacetyl-19-deoxyscalarin, 12-epi-scalarin, and 12-O-deacetyl-12-epi-scalarin, three indole alkaloids, 5-hydroxy-1H-indole-3-carbaldehyde, hyrtiosine A, and variabine B, and one norterpene, cavernosine were isolated from the marine sponge Hyrtios erectus. Their structures were determined by means of spectroscopic methods and the absolute configurations of the asymmetric centers were determined using the modified Mosher's method. The cytotoxic activities for the isolated compounds have been reported.

Antiplasmodial dimeric chalcone derivatives from the roots of Uvaria siamensis.

Four dimeric chalcone derivatives, 8″,9″-dihydrowelwitschin H, uvarins A-C, a naphthalene derivative, 2-hydroxy-3-methoxy-6-(4'- hydroxyphenyl)naphthalene, and the known dimeric chalcones, dependensin and welwitschin E, flavonoids, a cyclohexane oxide derivative, an aromatic aldehyde were isolated from the roots of Uvaria siamensis (Annonaceae). The structures of the compounds were elucidated by spectroscopic analysis, as well as by comparison with literature data. The isolated compounds with a sufficient amount for biological assays were evaluated for their antimalarial, antimycobacterial, and cytotoxic activities. The dimeric chalcones 8″,9″-dihydrowelwitschin H, uvarins B and C, dependensin and welwitschin E showed strong antiplasmodial activity with IC50 values of 3.10, 3.02, 3.09, 4.21 and 3.99 µg/mL, respectively. A possible biosynthesis pathway of the dimeric chalcones is discussed.

A new dihydrobenzofuran lignan and potential α-glucosidase inhibitory activity of isolated compounds from Mitrephora teysmannii.

A new dihydrobenzofuran lignan, (2R,3S)-2-(3',4'-dimethoxyphenyl)-5-(3-hydroxypropyl)-7-methoxy-2,3-dihydrobenzofuran-3-methyl acetate, named as mitredrusin (1), was isolated from the leaves of Mitrephora teysmannii (Annonaceae) together with 12 known compounds including a related dihydrobenzofuran lignan: (-)-3',4-di-O-methylcedrusin (2), four polyacetylenic acids: 13(E)-octadecene-9,11-diynoic acid (3), 13(E),17-octadecadiene-9,11-diynoic acid (4), octadeca-9,11,13-triynoic acid (5) and octadeca-17-en-9,11,13-triynoic acid (6), five lignans: (-)-eudesmin (7), (-)-epieudesmin (8), (-)-phillygenin (9), magnone A (10) and forsythialan B (11) and two megastigmans: (3S,5R,6S,7E,9R)-7-megastigmene-3,6,9-triol (12) and annoionol A (13). The chemical structures of these compounds were established on the basis of their 1-D and 2-D NMR spectroscopic data. All compounds were evaluated for their α-glucosidase inhibitory activity. Among these isolates, polyacetylenic acids 3 and 4 showed more than 20-fold much higher activity compared with that of the antidiabetic drug acarbose.

Ent-pimarane and ent-trachylobane diterpenoids from Mitrephora alba and their cytotoxicity against three human cancer cell lines.

Bioassay-guided fractionation of the hexane extract of the branches of Mitrephora alba led to the isolation of five diterpenoids: ent-8ß-hydroxypimar-15-en-18-oic acid, ent-15,16-dihydroxypimar-8(14)-en-18-oic acid, ent-3ß-hydroxytrachyloban-18-oic acid, ent-3ß-hydroxytrachyloban-18-al and methyl ent-3ß-hydroxytrachyloban-18-oate, together with five related known diterpenoids. The structures were elucidated by spectroscopic analysis and comparison with literature data. All isolated compounds were evaluated for their cytotoxic activities against three human cancer cell lines. The results showed that three ent-trachylobane diterpenes had moderate cytotoxicity against NCI-H187 cancer cells.

Two new C-benzylated dihydrochalcone derivatives from the leaves of Melodorum siamensis.

Two new C-benzylated dihydrochalcone derivatives, 4,2',4'-trihydroxy-6'-methoxy-3'(2''-hydroxybenzyl)dihydrochalcone (1) and 2',4'-dihydroxy-4,6'-dimethoxy-3'(2''-hydroxybenzyl)dihydrochalcone (2), along with six known flavonoid derivatives (3-8), a known dihydrochalcone dimer (9), three known aromatic esters (10-12), and one known aromatic amide (13), were isolated from the leaves of Melodorum siamensis. The structures of the compounds were elucidated by spectroscopic analysis, mainly 1D and 2D NMR techniques (1H, 13C, COSY, HMQC, and HMBC), as well as by comparison with literature data. The isolated compounds with a sufficient amount for biological assays were evaluated for their antimalarial, antimycobactirial, and cytotoxic activities. Compounds 1, 2, and 13 exhibited strong cytotoxicity against human tumor cell lines KB and NCI-H187, with IC50 values in the range of 0.66-7.16 µg/mL.

A new phenolic compound with anticancer activity from the wood of Millettia leucantha.

A new phenolic compound, 1-(3-hydroxy-4-methoxyphenyl)-3-(2,4-dihydroxy-5-methoxyphenyl) propan-1-ol, named as millettinol (1), along with six known compounds, medicarpin (2), 4-hydroxy-3-methoxy-8,9-methylenedioxypterocarpan (3), 5,4'-dihydroxy-7,8-dimethoxyisoflavone (4), physcion (5), (R)-(-)-mellein (6) and isoliquiritigenin (7), were isolated from the wood of Millettia leucantha. The structures of the compounds were determined by an analysis of their spectroscopic data. Some of the isolates were tested for anticancer activity. Compound 1 exhibited strong cytotoxicity against the BCA-1 tumor cell lines with an IC(50) = 3.44 µg/mL.

N-(9,11-Dimeth-oxy-4-oxo-2,3,4,6,7,11b-hexa-hydro-1H-pyrido[2,1-a]isoquinolin-3-yl)benzamide.

The title schulzeine derivative, C(22)H(24)N(2)O(4), crystallizes with two crystallographically independent mol-ecules of almost identical conformation in the asymmetric unit. The tricyclic core of schulzeine has a fused-three-ring system comprising the tetra-hydro-isoquinoline and δ-lactam moieties. In both mol-ecules, the pyridine ring adopts a twisted-boat conformation, whereas the lactam ring is in a boat conformation. The two meth-oxy groups are slightly twisted from the attached benzene ring [C-O-C-C torsion angles = -21.3 (2) and -20.5 (2)° in mol-ecule A, and -6.3 (2) and -16.2 (2)° in mol-ecule B] and the benzamide moiety is in a (-)-synclinal conformation with respect to the lactam ring. In the crystal, mol-ecules are linked into V-shaped dimers by inter-molecular N-H⋯O hydrogen bonds and weak C-H⋯O inter-actions. These dimers are stacked into V-shaped columns along the a axis. Adjacent columns are further linked in an anti-parallel manner. C-H⋯π inter-actions are also observed.

Anthraquinones from the roots of Prismatomeris malayana.

A novel anthraquinone, 1,3-dihydroxy-5,6-dimethoxy-2-methoxymethyl-9,10-anthraquinone (9) and a new natural product, 2-hydroxymethyl-1-methoxy-9,10-anthraquinone (8) were isolated from the roots of Prismatomeris malayana together with seven known anthraquinones, tectoquinone (1), 1-hydroxy-2-methyl-9,10-anthraquinone (2), rubiadin (3), rubiadin-1-methyl ether (4), 1,3-dihydroxy-5,6-dimethoxy-2-methyl-9,10-anthraquinone (5), nordamnacanthal (6), and damnacanthal (7). Their structures were determined on the basis of spectroscopic data. Some of the anthraquinones were tested for anticancer, antifungal, and antimalarial activities.

Constituents of the leaves of Holarrhena pubescens.

The leaves of Holarrhena pubescens yielded a new naringenin glycoside (1), together with naringin, naringenin 7-O-beta-D-glucoside, lupeol, lupeol beta-hydroxyhexadecanoate and ursolic acid. The structure of 1 was determined by spectral analysis.

Anti-inflammatory activity of 4-arylcoumarins from endophytic Streptomyces aureofaciens CMUAc130 in murine macrophage RAW 264.7 cells.

This research was undertaken to test the in vitro anti-inflammatory action of 5,7,4'-trimethoxy-4-phenylcoumarin and 5,7-dimethoxy-4-phenylcoumarin produced by Streptomyces aureofaciens CMUAc130. The effects of the two coumarins were investigated on the formation of NO, PGE2, and TNF-alpha and also on inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-induced murine macrophage RAW 264.7 cells. The data obtained were consistent with the modulation of iNOS enzyme expression. A similar effect was also observed when LPS-induced PGE2 release and COX-2 expression were tested. The inhibitory effects were shown in concentration-dependent manners. The 5,7,4'-Trimethoxy-4-phenylcoumarin and 5,7-dimethoxy-4-phenylcoumarin also mildly but significantly reduced the formation of TNF-alpha.

Chemical constituents of the roots of Piper sarmentosum.

Sixteen compounds were isolated from the fresh roots of Piper sarmentosum. Seven of these have been previously isolated from the fruits and leaves of this plant: the aromatic alkene (1), 1-allyl-2-methoxy-4,5-methylenedioxybenzene (4), beta-sitosterol, pyrrole amide (6), sarmentine (10), sarmentosine (13) and pellitorine (14). (+)-Sesamin (2), horsfieldin (3), two pyrrolidine amides 11 and 12, guineensine (15) and brachystamide B (16) are new for P. sarmentosum. Sarmentamide A, B, and C (7-9) are new natural products. Compounds 1--4 and 6--16 were tested for antiplasmodial, antimycobacterial and antifungal activities.

Chromones from the branches of Harrisonia perforata.

Four new chromones, perforamone A, B, C, and D have been isolated together with six known compounds, peucenin-7-methyl ether, O-methylalloptaeroxylin, perforatic acid, eugenin, saikochromone A and greveichromenol, from the branches of Harrisonia perforata (Simaroubaceae). The structures were identified by spectroscopic data. The compounds were tested for antimycobacterial and antiplasmodial activities.

Cerebrosides and a monoacylmonogalactosylglycerol from Clinacanthus nutans.

A mixture of nine cerebrosides and a monoacylmonogalactosylglycerol were separated from the leaves of Clinacanthus nutans. The structures of the cerebrosides were characterized as 1-O-beta-D-glucosides of phytosphingosines, which comprised a common long-chain base, (2S,3S,4R,8Z)-2-amino-8(Z)-octadecene-1,3,4-triol with nine 2-hydroxy fatty acids of varying chain lengths (C(16), C(18), C(20-26)) linked to the amino group. The glycosylglyceride was characterized as (2S)-1-O-linolenoyl-3-O-beta-D-galactopyranosylglycerol. The structures were established on the basis of the spectroscopic data and chemical reactions.

Sulfur-containing compounds from Clinacanthus siamensis.

Two new sulfur-containing compounds, trans-3-methylsulfonyl-2-propenol (1) and trans-3-methylsulfinyl-2-propenol (2) were isolated together with trans-3-methylthioacrylamide (3), entadamide A (4) and entadamide C (5) from the leaves of Clinacanthus siamensis. The structures were established on the basis of the spectroscopic data. The compounds were tested for antimalarial and antimycobacterial activity.