New constituents from Crinum latifolium with inhibitory effects against tube-like formation of human umbilical venous endothelial cells.

Six compounds (1-6) were isolated from the methanol extract of Crinum latifolium by bioassay-guided separation. Among the six isolates, compounds 2 and 6 were new metabolites. Their structures were established as 4-senecioyloxymethyl-3,4-dimethoxycoumarin (2) and 5,6,3'-trihydroxy-7,8,4'-trimethoxyflavone (6) based on spectroscopic analyses. Compound 2 was found to be strongly inhibitory against the in vitro tube-like formation of human umbilical venous endothelial cells (HUVECs) while manifesting no cytotoxicity in tumor cell lines (B16F10, HCT116). Significant inhibitory activity (inhibition percentage, 53.5%) was still observed at concentrations as low as 1 microg/mL. Compound 6 showed a modest inhibitory effect on the tube-like formation of HUVECs. Other compounds, including cycloartenol (1), 4',7-dihydroxy-3'-methoxyflavan (3), 4',7-dihydroxyflavan (4), and 2',4',7-trihydroxydihydrochalcone (5) were found to be nearly inactive.

Synthesis and cytotoxicity of 2,5-dihydroxychalcones and related compounds.

A series of 2, 5-dihydroxychalcones and related compounds were synthesized, and their cytotoxicities against tumor cell lines and human umbilical venous endothelial cells (HUVEC) evaluated. It was found that chalcones, with electron-withdrawing substituents on an A ring, exhibited significant cytotoxicities. Among the synthesized compounds, 2'-chloro-2, 5-dihydroxychalcone (9) was most potent, with an IC50 value as low as 0.31 microg/mL. This compound also exhibited a significant cytotoxic selectivity toward HUVEC.

Antioxidant and antiinflammatory activities of ventol, a phlorotannin-rich natural agent derived from Ecklonia cava, and its effect on proteoglycan degradation in cartilage explant culture.

Osteoarthritis is thought to be induced by the aging-related loss of homeostatic balance between degeneration and repair mechanism around cartilage tissue in which inflammatory mediators such as reactive oxygen species, cytokines and prostaglandins are prone to overproduction under undesirable physiological conditions. Phlorotannins are unique polyphenolic compounds bearing dibenzo-1,4-dioxin skeleton which are not found in terrestrial plants but found only in some brown algal species such as Ecklonia and Eisenia families. Phlorotannin-rich extracts of Ecklonia cava including ventol showed significant antioxidant activities such as DPPH radical scavenging, ferric ion reducing power, peroxynitrite scavenging and inhibition of LDL oxidation, indicating their possible antioxidative interference both in onset and downstream consequences of osteoarthritis. Ventol also showed significant down regulation of PGE2 generation in LPS-treated RAW 246.7 cells, and significant inhibition of human recombinant interleukin-1alpha-induced proteoglycan degradation, indicating its beneficial involvement in pathophysiological consequences of osteoarthritis, the mechanism of which needs further investigation. Since ventol showed strong therapeutic potentials in arthritic treatment through several in vitro experiments, it is highly encouraged to perform further mechanistic and efficacy studies.

Water soluble prodrugs of the antitumor agent 3-[(3-amino-4-methoxy)phenyl]-2-(3,4,5-trimethoxyphenyl)cyclopent-2-ene-1-one.

Fourteen prodrugs of the antitumor agent 3-[(3-amino-4-methoxy)phenyl]-2-(3,4,5-trimethoxyphenyl)cyclopent-2-ene-1-one (1) were prepared to improve its water solubility and potency. These prodrugs include alpha-amino acid (1a-1h), aliphatic amino acid (1i-1l), phosphoramidate (1m), and phosphate (1n) derivatives. All of the prodrugs showed improved water solubility. A number of the amino acid prodrugs (1a, 1b, 1d-1f, 1h, 1j, and 1k) exhibited more potent antitumor activity compared to the parent compound (1). The phosphate prodrug 1n also offered a potent antitumor activity, but the phosphoramidate 1m did not show any antitumor activity in vivo. None of the prodrugs exhibited significant toxicities in mice. These results indicate that the design and preparation of the amino acid prodrugs (1a, 1b, 1d-1f, 1h, 1j, and 1k) and phosphate prodrug (1n) are beneficial for enhancing the antitumor activity of 1. The similar approaches may be used to improve water solubility and bioactivity of other poorly soluble aromatic amines.

Cytotoxic 2',5'-dihydroxychalcones with unexpected antiangiogenic activity.

A series of 2',5'-dihydroxychalcones were synthesized and evaluated for cytotoxicity against tumor cell lines and human umbilical venous endothelial cells (HUVEC). It was found that chalcones with electron-withdrawing substituents on the B ring exhibited potent cytotoxicity against a variety of tumor cell lines while compounds with electron-releasing groups were less potent in general. Those compounds with B ring replaced by extended or heteroaromatic rings exhibited significant bioactivity. Several compounds were shown to have marked cytotoxic selectivity towards HUVECs. Especially, among the synthesized compounds, 2-chloro-2',5'-dihydroxychalcone (2-3) showed the highest selectivity index up to 66 in comparison to HCT116 cells. This compound also exhibited strong inhibitory effects on the HUVEC tube formation in an in vitro model. When administered into BDF1 mice bearing Lewis lung carcinoma cells at 50 mg kg(-1) day(-1), 2-3 was found to inhibit the growth of tumor mass by 60.5%.

Antiinvasive, antiangiogenic and antitumour activity of Ephedra sinica extract.

A water fraction (EW), the remaining water phase from the methanol extract of Ephedra sinica after extraction with ethyl acetate and butanol, has been investigated for its antiangiogenic, antiinvasive and antitumour activities. It was observed that EW, at 30 micro g/mL, a non-cytotoxic concentration, inhibited the tube formation induced by human umbilical venous endothelial cells and the invasion of B16F10 melanoma cells through a matrix membrane by more than 90%. At 30 mg/kg/day, the inhibitory activity of EW on the growth of a tumour mass in BDF1 mice inoculated with B16-F10 murine melanoma cells was comparable to that of adriamycin (ADR) administered at 2 mg/kg/day. From these results, it could be postulated that the antitumour activity of the water fraction might be attributed to its antiangiogenic and antiinvasive activities.

Synthesis and cytotoxicity of some rigid derivatives of methyl 2,5-dihydroxycinnamate.

Eight rigid compounds designed as esterase-stable analogues of methyl 2,5-dihydroxycinnamate (1) were synthesized. These derivatives include 2-(2',5'-dihydroxybenzylidene)cyclopentenone (3a), 2-(2',5'-dihydroxybenzylidene)cyclohexanone (3b), 2,6-bis(2',5'-dihydroxybenzylidene)cyclohexanone (4b), 2,6-bis(2',5'-dihydroxybenzylidene)cyclopentenone (4a), (E)-3-(2',5'-dihydroxybenzylidene)pyrrolidin-2-one (5), (E)-5-(2',5'-dihydroxybenzylidene)-1,2-isothiazolidine-1,1-dioxide (6), 4-(2',5'-dihydroxyphenyl)-5H-furan-2-one (7), and 3-(2',5'-dihydroxyphenyl)cyclopent-2-ene-1-one (8). Among the eight compounds, the furanone 7 and cyclopentenone 8 showed the most potent cytotoxicity with IC50 values of 0.39-0.98 microg/mL. Compound 8 was further brominated, phenylated and methylated at the alpha position to give three corresponding analogues, including 2-bromo-3-(2',5'-dihydroxyphenyl)cyclopent-2-ene-1-one (24), 3-(2',5'-dihydroxyphenyl)-2-phenylcyclopent-2-ene-1-one (27), and 3-(2',5'-dihydroxyphenyl)-2-methylcyclopent-2-ene-1-one (28). Among the three, the most enhanced activity was observed with the phenylated compound 27.

Synthesis, cytotoxicity and antitumor activity of 2,3-diarylcyclopent-2-ene-1-ones.

Two series of 2,3-diarylcyclopent-2-ene-1-ones including 2-aryl-3-(2,5-dihydroxyphenyl)cyclopent-2-ene-1-ones (2a-2f) and 3-aryl-2-3',4',5'-trimethoxyphenyl)cyclopent-2-ene-1-one (3a-3j) were synthesized and evaluated for the cytotoxicity against three tumor cell lines; B16F10, HCT116 and A431. It was found that the 3,4,5-trimethoxy substituent was optimal for the bioactivity of compounds in series 2. Meanwhile, compounds in series 3 exhibited the most potent cytotoxicity with 3-aryl ring being 4-methoxyphenyl (compound 3f), (3-hydroxy-4-methoxy)phenyl (compound 3e), or (3-amino-4-methoxy)phenyl (compound 3j).

Preliminary structure-antiangiogenic activity relationships of 4-senecioyloxymethyl-6,7-dimethoxycoumarin.

Through a systematic modification of the novel angiogenesis inhibitor 4-senecioyloxymethyl-6,7-dimethoxycoumarin (1) we found that a 6,7-dimethoxy moiety is important for bioactivity of 1. Replacement of the lactone functionality in coumarin 1 by an amide decreased its activity. By substitution of the senecioyl chain with various cinnamoyl groups we discovered 6d, bearing a 4-methoxycinnamoyl instead of senecioyl side chain, with inhibitory activity in HUVEC tube formation assay enhanced by one order of magnitude compared to 1. We have also synthesized compound 12, an analogue of 6d, with equipotency and improved water solubility.

Synthesis and anti-tumor activity of novel combretastatins: combretocyclopentenones and related analogues.

A series of 2-(3,4,5-trimethoxyphenyl)-3-arylcyclopent-2-ene-1-ones (8a-8e) and their related analogues, including pentenone 9a, pentenol 10a, pentene 12a, and furane 15, were synthesized and evaluated for cytotoxicity against murine and human tumor cell lines. Compounds 8a-c, 8e and 9a showed strong cytotoxicity with IC(50) values in the range of 8-34ng/mL. Compound 8e exhibited significant anti-tumor activity in BDF1 mice bearing Lewis lung carcinoma cells with an inhibition ratio of 59%.

A novel stereo-selective sulfonylurea, 1-[1-(4-aminobenzoyl)-2,3-dihydro-1H-indol-6-sulfonyl]-4-phenyl-imidazolidin-2-one, has antitumor efficacy in in vitro and in vivo tumor models.

The antitumor activities of novel 1-[1-(4-aminobenzoyl)-2,3-dihydro-1H-indol-6-sulfonyl]-4-phenyl-imidazolidin-2-ones were studied to determine the potential of these compounds as antitumor candidates. The agents studied were: DW2143 (1-[1-(4-aminobenzoyl)-2,3-dihydro-1H-indol-6-sulfonyl]-4-phenyl-imidazolidin-2-one), a racemic mixture, and DW2282 [(4S)-1-[1-(4-aminobenzoyl)-2,3-dihydro-1H-indol-6-sulfonyl]-4-phenyl-imidazolidin-2-one], an S-isomer. DW2143 and DW2282 suppressed the in vitro growth of tumor cells at lower concentrations than doxorubicin, but tumor specificity was not observed between the compounds. These compounds when administered orally were not active in syngeneic models of murine Colon 26 adenocarcinoma and L1210 leukemia. However, DW2143 suppressed the growth of SW620 (human colon cancer) and NCI-H23 (human lung cancer) cells in nude mice, inhibiting tumor growth by 87 and 67%, respectively. DW2282 was a more potent inhibitor of SW620 tumor cell growth in nude mice and was also lower in toxicity than DW2143. Moreover, DW2282 did not produce a series of toxic symptoms caused by the aniline metabolites of sulfonylureas, including hypoglycemia. These results suggest that DW2282, an S-isomer, could be a novel antitumor candidate with higher specificity and lower toxicity than other orally active sulfonylureas.