Inhibition of LPS-stimulated NO production in mouse macrophage-like cells by azulenequinones.

Azulenequinone derivatives have been reported to display a broad spectrum of biological activities, but study at the cellular level has been limited. The effect of twenty-seven azulenequinone derivatives on nitric oxide (NO) production by mouse macrophage-like cells Raw 264.7 was investigated in this study. All of these compounds failed to stimulate the Raw 264.7 cells to produce detectable amounts of NO, but did inhibit NO production by lipopolysaccharide (LPS)-activated Raw 264. 7 cells to varying extents. Compounds [7, 8, 9, 13, 16, 25, 27], which showed lesser cytotoxic activity (CC50 = 425, 381, 482, 179, 119, 235, 225 microM, respectively), inhibited NO production to the greatest extent [selectivity index (SI) = 15.4, 26.2, 3.9, 21.6, 3.1, 6.0, 8.4, respectively]. Western blot and RT-PCR analyses demonstrated that the most active derivatives, 3-morpholino-1, 5-azulenequinone [8] and 3,7-dibromo-1, 5-azulenequinone [13], significantly reduced both the intracellular concentration of iNOS protein and the expression of iNOS mRNA. ESR spectroscopy showed that compounds [8, 13] weakly scavenged NO produced by NOC-7, possibly via their general reducing activity. These data suggest that the inhibitory effect of NO production by compounds [8, 13] might be generated mostly via the inhibition of iNOS expression, rather than the radical-mediated mechanism.

Relationship between differentiation-inducing activity and hypercalcemic activity of hexafluorotrihydroxyvitamin D3 derivatives.

Among 16 newly synthesized hexafluorotrihydroxyvitamin D3 derivatives, 24-Homo-26,26,26,27,27,27-hexafluoro (24H-F6)-1,24(S), 25(OH)3 vitamin D3 (VD3) (DD-011) [16] induced differentiation (i.e., appearance of NBT-positive cells) of human promyelocytic leukemic HL-60 cells most efficiently (EC50=0.5 nM), followed by 24H-F6-1,25(OH)2-22-oxa-VD3 (DD-006) [11] > F6-1,25(OH)2-VD3 (F6VD3) [2] > F6-1,25(OH)2-22-ene-VD3 (DD-009) [14] > 24H-F6-1,25(OH)2-VD3 (F6C28) [3] > 24H-F6-1,25(OH)2-1,23(S),25(OH)3-VD3 (DD-015) [18] > 24H-F6-1,25(OH)2-22-ene-VD3 (mvd1400) [6] > 22H-F6-1,25(OH)2-24-ene-VD3 (mvd3400) [5] > 24H-F6-1,23(R),25(OH)3-VD3 (DD-014) [17] > 24H-F6-1,22(S),25(OH)3-VD3 (DD-003) [7] > 24H-F6-1,22(S),25(OH)3-24-yne-VD3 (DD-005) [9] > 24H-F6-1,22(R),25(OH)3-24-yne-VD3 (mvd-1235) [10] > F6-1,25(OH)2-22-ene-VD3 (DD-008) [13] = 1,25(OH)2VD3 [1] (CC50=6 nM). On the other hand, 24H-F6-1,22(R),25(OH)3-VD3 (DD-004) [8], which is an isomer of DD-003 [7], showed much reduced activity (CC50=100 nM), suggesting the importance of the configuration of the OH group at the C-22. When their differentiation-inducing activity was plotted vs. the octanol-water partition coefficient (log P) used as a parameter of hydrophobicity, a bell-shaped curve was produced, with the bottom at log P=5.4-5.8. There was no clear-cut relationship between the differentiation-inducing activity and hypercalcemic activity (serum calcium elevating activity). Compounds [3, 7, 11, 17] showed relatively higher differentiation-inducing activity, with lesser hypercalcemic activity, as compared with [1]. Administration of [7] showed potent antiproliferation activity against colon cancer transplanted in nude mice. These results further confirmed the antitumor potential of hexafluorotrihydroxyvitamin D3 derivatives.

Diverse biological activities of fermented pine seed shell extract.

Intraperitoneal administration of fermented pine seed shell extract (PSSE) (up to 2 g/kg) induced no apparent acute toxicity to mice. Pretreatment of mice with PSSE protected them from the lethality of Escherichia coli infection. PSSE showed a very weak cytotoxic activity against both normal and tumor cells and no anti-HIV activity, but stimulated the mouse macrophage-like Raw 264.7 cells to produce nitric oxide (NO) and citrulline. ESR spectroscopy showed that PSSE produced no detectable radicals, but effectively scavenged O2- (generated by the hypoxanthine-xanthine oxidase reaction), hydroxyl radical (generated by the Fenton reaction) and NO (generated by NOC-7). Comparison of PSSE with other natural products, such as polyphenols and vitamins, further confirmed the close association between radical intensity and radical scavenging activity, suggesting the bimodal action of natural products. Although the biological activities of PSSE were relatively lower than those of other natural products, the present study suggests the possible medicinal efficacy of PSSE.

Radical scavenging activity and cytotoxicity of ferulic acid.

Ferulic acid and eugenol were examined for their superoxide (O2-), hydroxyl radical (.OH) and nitric oxide (NO)-scavenging ability, using ESR spectroscopy with spin trap agents DMPO and carboxy-PTIO/NOC-7. Ferulic acid more efficiently scavenged .OH and NO than eugenol. The O2- scavenging activity of ferulic acid was comparable with that of eugenol. Ferulic acid significantly reduced the NO production by lipopolysaccharide (LPS)-stimulated mouse macrophage-like cells (Raw 264.7 cells) compared to eugenol. The cytotoxic activity of ferulic acid against Raw 264.7 cells was comparable with that against human submandibular gland carcinoma (HSG) cells and the cytotoxicity of ferulic acid was about 10-fold smaller than that of eugenol. The stoichiometric factor (n) (number of moles of peroxy radical trapped by moles of the relevant phenol) of ferulic acid and eugenol was investigated, using the induction period methods of the methyl methacrylate polymerization system. The n-value of ferulic acid (1.5) was higher than that of eugenol (1.0) and was similar to that of 2, 6-di-t-butyl-4-methylphenol (BHT). Ferulic acid as well as eugenol may produce a dimer during the induction period due to an n-value less than 2. These results suggested that ferulic acid may be useful for preventing cell damage perhaps caused by O2-, and in particular by .OH and NO, in living systems.