Bioassay-guided fractionation of the extracts of Zieridium pseudobtusifolium and Acronychia porteri led to the isolation of 5,3'-dihydroxy-3,6,7,8,4'-pentamethoxyflavone [1], which showed activity against (KB) human nasopharyngeal carcinoma cells (IC50 0.04 micrograms/ml) and inhibited tubulin assembly into microtubules (IC50 12 microM). Two other known flavonols, digicitrin [2] and 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone [5], were also isolated together with three new ones, 3-O-demethyldigicitrin [3], 3,5,3'-trihydroxy-6,7,8,4'-tetramethoxyflavone [4], and 3,5-dihydroxy-6,7,8,3',4'-pentamethoxyflavone [6]. All of these flavonols showed cytotoxic activity against KB cells.
A series of indole alkaloids of the aspidofractinine-type was assessed for their potential in reversing MDR in vincristine-resistant KB cells. Of the compounds tested, kopsiflorine, kopsamine, pleiocarpine, 11-methoxykopsilongine, lahadinine A and N-methoxycarbonyl-11,12-methylenedioxy-delta 16,17-kopsinine were found to show appreciable activity.
Leaf extracts of Garcinia parvifolia provided relatively high yields of four novel, cytotoxic prenylated depsidones. The structures were determined mainly by detailed NMR spectral analysis and X-ray crystallography.
Two new prenylated compounds, the benzoquinone atrovirinone (1) and the depsidone atrovirisidone (2), were isolated from the roots of Garcinia atroviridis. Their structures were determined on the basis of the analysis of spectroscopic data. While compound 2 showed some cytotoxicity against HeLa cells, both compounds 1 and 2 were only mildly inhibitory toward Bacillus cereus and Staphylococcus aureus.
Bioassay (P388 lymphocytic leukemia cell line and human tumor cell lines)-guided separation of the extracts prepared from the tropical and coastal trees Hernandia peltata (Malaysia) and Hernandianymphaeifolia (Republic of Maldives) led to the isolation of a new lignan designated as hernanol (1) and 12 previously known lignans: (-)-deoxypodophyllotoxin (2), deoxypicropodophyllin (3), (+)-epiaschantin (4), (+)-epieudesmin (5), praderin (6), 5'-methoxyyatein (7), podorhizol (8), deoxypodorhizone (9), bursehernin (10), kusunokinol (11), clusin (12), and (-)-maculatin (13). The oxidative cyclization (with VOF(3)) of lignans 8, 9, and 10 resulted in a new and unusual benzopyran (14), isostegane (15), and a new dibenzocyclooctadiene lactone (16), respectively. The structure and relative stereochemistry of hernanol (1) and lignans 3, 7, 8, 9, 10, 11, and 12 were determined by 1D and 2DNMR and HRMS analyses. The structures and absolute stereochemistry of structures 2, 4, 5, 6, 13, 14, 15, and 16 were unequivocally determined by single-crystal X-ray diffraction analyses. Evaluation against the murine P388 lymphocytic leukemia cell line and human tumor cell lines showed podophyllotoxin derivatives 2 and 3 to be strong cancer cell line growth inhibitors and substances 4, 5, 8, and 15 to have marginal cancer cell line inhibitory activities. Seven of the lignans and one of the synthetic modifications (14) inhibited growth of the pathogenic bacterium Neisseria gonorrhoeae.
Epipremnum pinnatum (L.) Engl. hexane extract produced a significant growth inhibition against T-47D breast carcinoma cells and analysis of cell death mechanisms indicated that the extract elicited a non-apoptotic programmed cell death. T-47D cells exposed to the extract at EC(50) concentration (72 h) for 24 h failed to demonstrate typical DNA fragmentation associated with apoptosis, as carried out using a modified TUNEL assay. In addition, acute exposure to the extract produced an insignificant regulation of caspase-3 and p53 mRNA expression but increased in the c-myc mRNA expression. Ultrastructural analysis using transmission electron microscope demonstrated distinct vacuolated cells, which strongly indicated a Type II non-apoptotic cell death although the changes in chromatin were also detected. The presence of non-apoptotic programmed cell death was then reconfirmed with annexin-V and propidium iodide staining. These findings suggested that up-regulation of c-myc mRNA expression may have contributed to the growth arrest and Type II non-apoptotic programmed cell death in the Epipremnum pinnatum (L.) Engl. hexane extract-treated T-47D cells.
A new labdane diterpene glucoside, curcumanggoside (1), together with nine known compounds, including labda-8(17),12-diene-15,16-dial (2), calcaratarin A (3), zerumin B (4), scopoletin, demethoxycurcumin, bisdemethoxycurcumin, 1,7-bis(4-hydroxyphenyl)-1,4,6-heptatrien-3-one, curcumin, and p-hydroxycinnamic acid, have been isolated from the rhizomes of Curcuma mangga. Their structures were determined using a combination of 1D (1H NMR, 13C NMR, DEPT) and 2D (COSY, HSQC, HMBC) NMR techniques. All diarylheptanoids and scopoletin showed significant antioxidant activity. Zerumin B, demethoxycurcumin, bisdemethoxycurcumin, and curcumin also exhibited cytotoxic activity against a panel of five human tumor cell lines.
Investigation on the leaves of Melicope bonwickii (F.Muell.) T.Hartley (Rutaceae) afforded a new 7-(2'-hydroxy-3'-chloroprenyloxy)-4-methoxyfuroquinoline (1) together with the known 7-(2',3'-epoxyprenyloxy)-4-methoxyfuroquinoline (2), evellerine (3) kokusaginine (4) and an amide aurantiamide acetate (5). Compounds 1 and 2 showed significant activity against cervical cell lines (Hela).
Nine new indole alkaloids, rhazinoline (1), 19(S)-methoxytubotaiwine (2), 19(R)-methoxytubotaiwine (3), kopsamidine A (4), kopsamidine B (5), kopsinidine A (6), kopsinidine B (7), paucidactine C (8), and pericine N-oxide (9), in addition to several recently reported novel indoles and 34 other known ones, were obtained from the stem-bark extract of the Malayan Kopsia arborea. The structures were determined using NMR and MS analysis. Valparicine (12) showed pronounced cytotoxic effects against KB and Jurkat cells (IC(50) 13.0 and 0.91 microM, respectively).
Eleven new indole alkaloids, in addition to the previously reported rhazinal (1), and 14 other known alkaloids, were obtained from the Malayan Kopsia singapurensis, viz., kopsiloscines A-F (2-7), 16-epikopsinine (8), kopsilongine- N-oxide (9), 16-epiakuammiline (10), aspidophylline A (11), and vincophylline (12). The structures of these alkaloids were determined using NMR and MS analyses. Rhazinal (1), rhazinilam (17), and rhazinicine (18) showed appreciable cytotoxicity toward drug-sensitive as well as vincristine-resistant KB cells, while kopsiloscines A (2), B (3), and D (5) and aspidophylline A (11) were found to reverse drug-resistance in drug-resistant KB cells.
Ten new indole alkaloids of the aspidofractinine type, in addition to several recently reported indole alkaloids and 20 other known alkaloids, were obtained from the leaf and stem-bark extract of the Malayan Kopsia singapurensis, viz., kopsimalines A-E (1-5), kopsinicine (6), kopsofinone (7), and kopsiloscines H-J (8-10). The structures of these alkaloids were determined using NMR and MS analysis. Kopsimalines A (1), B (2), C (3), D (4), and E (5) and kopsiloscine J (10) were found to reverse multidrug-resistance in vincristine-resistant KB cells, with 1 showing the highest potency.
A new cycloartane, monocarpinine (1), incorporating a fused tetrahydrofuranyl ring, and a cytotoxic tetracyclic lactam, monomarginine (2), were isolated from a stem bark extract of the Malayan species Monocarpia marginalis. The structures of these compounds were determined using NMR and MS analysis. Monomarginine (2) showed appreciable cytotoxicity toward human KB (both drug-sensitive and drug-resistant) and Jurkat cells.
The bark of Cryptocarya crassinervia provided two new phenantrene alkaloids, 2-hydroxyatherosperminine (1) and N-demethyl-2-methoxyatherosperminine (2).
Seven new indole alkaloids of the Aspidosperma type, jerantinines A-G (1-7), were isolated from a leaf extract of the Malayan Tabernaemontana corymbosa. The structures were established using NMR and MS analysis. Five of the alkaloids isolated and two derivatives (1-5, 8, 9) displayed pronounced in vitro cytotoxicity against human KB cells (IC50 < 1 microg/mL).
The nuclear factor-kappaB (NF-kappaB) signaling pathway is constitutively active in many types of cancers and is a potential therapeutic target. Using a cell-based assay for stability of inhibitor of kappa B (IkappaB), a critical regulator of NF-kappaB activity, we found that an organic solvent extract of the plant Cryptocarya rugulosa inhibited constitutive NF-kappaB activity in human lymphoma cell lines. The active components were identified as rugulactone, a new alpha-pyrone (1), and the known cryptocaryone (2). Rugulactone was the more active compound, exhibiting up to 5-fold induction of IkappaB at 25 microg/mL; maximal activity was observed with 10 h exposure of test cells to 1 or 2.
A new bisindole alkaloid, bisnicalaterine A (1), consisting of two vobasine-type skeletons, and 3-epivobasinol (2) and 3-O-methylepivobasinol (3), with vobasine-type skeletons, were isolated from the leaves of Hunteria zeylanica, and their structures were elucidated on the basis of spectroscopic data and chemical correlation. Bisnicalaterine A showed moderate cytotoxicity against various human cancer cell lines.
A cytotoxic bisindole alkaloid possessing an unprecedented structure constituted from the union of an eburnan half and a novel vinylquinoline alkaloid has been isolated from Leuconotis griffithii. The structure was established by analysis of the spectroscopic data and confirmed by X-ray diffraction analysis. A possible biogenetic pathway to the novel quinolinic coupling partner is presented from an Aspidosperma precursor.
Four new chromone alkaloids, chrotacumines A-D (1-4), consisting of a 5,7-dihydroxy-2-methylchromone, an N-Me piperidine ring, and an ester side chain were isolated from Dysoxylum acutangulum, and their structures including absolute configurations were elucidated on the basis of spectroscopic data interpretation including 2D NMR, CD spectra, and X-ray analysis. The known compound rohitukine (5) showed moderate cytotoxicity against human HL-60 promyelocytic leukemia and HCT-116 colon cancer cells.
Typhonium flagelliforme is an indigenous plant of Malaysia and is used by the local communities to treat cancer. This study aims to identify the chemical constituents of Typhonium flagelliforme particularly those which have antiproliferative properties towards human cancer cell lines.
Thirteen Malaysian plants; Artocarpus champeden, Azadirachta indica, Fragaria x ananassa, Garcinia mangostana, Lawsonia inermis, Mangifera indica, Nephelium lappaceum, Nephelium mutobile, Peltophorum pterocarpum, Psidium guajava and Syzygium aqueum, selected for their use in traditional medicine, were subjected to a variety of assays. Antioxidant capability, total phenolic content, elemental composition, as well as it cytotoxity to several cell lines of the aqueous and ethanolic extracts from different parts of these selected Malaysian plants were determined. In general, the ethanolic extracts were better free radical scavengers than the aqueous extracts and some of the tested extracts were even more potent than a commercial grape seed preparation. Similar results were seen in the lipid peroxidation inhibition studies. Our findings also showed a strong correlation of antioxidant activity with the total phenolic content. These extracts when tested for its heavy metals content, were found to be below permissible value for nutraceutical application. In addition, most of the extracts were found not cytotoxic to 3T3 and 4T1 cells at concentrations as high as 100 microg/mL. We conclude that although traditionally these plants are used in the aqueous form, its commercial preparation could be achieved using ethanol since a high total phenolic content and antioxidant activity is associated with this method of preparation.