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marine sponges ( porifera ) are well - known as prolific producers of bioactive metabolites . a sesquiterpene quinone , ilimaquinone , was reported in 1979 , and since then , related compounds have been obtained from several genera of marine sponge [ 39 ] .
we have isolated 11 sesquiterpene quinones : ilimaquinone ( 1 )   and its 5-epimer ( 2 ) , smenospongidine ( 3 )   and its 5-epimer ( 4 ) , smenospongiarine ( 5 )   and its 5-epimer ( 6 ) , smenospongine ( 7 )   and its 5-epimer ( 8) , dactyloquinone b , 18-hydroxy-5-epihyrtiophenol , and pelorol , from hippospongia sp . collected in palau , and reported the effects of these compounds on the production of an inflammatory cytokine , interleukin-8 ( il-8 ) , in tetradecanoyl phorbol acetate ( pma)-stimulated human promyelocytic leukemia hl-60 cells .
il-8 is a member of the superfamily of c - x - c chemokines and a chemotactic factor for t - cells , neutrophils , and basophils .
expression of il-8 has been detected in a variety of human cancers and is suggested to be a factor involved in tumor progression and metastasis [ 1215 ] .
compounds 38 increased the production of il-8 ; therefore , we examined the effects of compounds 18 on the production of one of the most well - known and important inflammatory cytokines , tnf- , in lipopolysaccharide ( lps)-stimulated murine monocytic leukemia raw 264.7 cells .
the raw 264.7 cell line was obtained from the japanese cancer research resources bank ( jcrb , kamiyoga , tokyo , japan ) .
this cell line was maintained in tissue culture dishes in rpmi 1640 medium ( nissui seiyaku , tokyo , japan ) , supplemented with 10% heat - inactivated fcs , 2 mm glutamine , 100 u / ml of penicillin g and 100 g / ml of streptomycin .
tnf- concentrations of the culture supernatants under control and various test conditions were measured by elisa using a combination of monoclonal and polyclonal antibodies .
cell proliferation was evaluated by enumerating the viable cells using the mtt formazan production method .
raw264.7 cells ( 1  10 cells / ml ) were treated with lps ( with or without test compounds ) and then transferred to 96-well microtiter plates .
after incubation for 24 h , 20 l of mtt reagent ( 5 mg / ml in pbs ) was added to each well and further incubated for 3 h. the production of formazan was assessed by measuring optical density ( od570 nm ) .
data are shown as the values relative ( % ) to each pma - stimulated optical density .
the raw 264.7 cell line was obtained from the japanese cancer research resources bank ( jcrb , kamiyoga , tokyo , japan ) .
this cell line was maintained in tissue culture dishes in rpmi 1640 medium ( nissui seiyaku , tokyo , japan ) , supplemented with 10% heat - inactivated fcs , 2 mm glutamine , 100 u / ml of penicillin g and 100 g / ml of streptomycin .
tnf- concentrations of the culture supernatants under control and various test conditions were measured by elisa using a combination of monoclonal and polyclonal antibodies .
cell proliferation was evaluated by enumerating the viable cells using the mtt formazan production method .
raw264.7 cells ( 1  10 cells / ml ) were treated with lps ( with or without test compounds ) and then transferred to 96-well microtiter plates .
after incubation for 24 h , 20 l of mtt reagent ( 5 mg / ml in pbs ) was added to each well and further incubated for 3 h. the production of formazan was assessed by measuring optical density ( od570 nm ) .
data are shown as the values relative ( % ) to each pma - stimulated optical density .
raw 264.7 cells are known to produce tnf- in response to the addition of lps , and this system is used to detect the modulating activities of compounds on tnf- production .
5-epi - smenospongine ( 8) stimulated the production of tnf- to a level three times greater than the control , but compounds 17 did not show any apparent activity ( fig .
compounds 3 , 5 , and 7 exhibited stronger activity on the promotion of il-8 production than the corresponding 5-epimers 4 , 6 , and 8 in pma - stimulated hl-60 cells , which showed the contribution of the trans - decaline ring in enhancing activity .
the basic functional group at c-18 increased il-8 production , since 38 exhibited stronger activities than 1 and 2 .
it was therefore revealed that the production of tnf- induced by 8 involves a different mechanism from that involved in il-8 production .
ilimaquinone ( 1 ) showed antibacterial , cytotoxic , anti - hiv , hemolytic , and antimitotic activities , disruption of the golgi apparatus , inhibition of the cytotoxicity of ricin and diphtheria toxin , and differentiation - inducing activity [ 5 , 1722 ] .
compounds 25 and 7 were reported to have cytotoxic , antibacterial , and hemolytic activities [ 4 , 5 , 17 ] .
compounds 24 , 7 , and 8 induced the differentiation of k562 cells into erythroblasts , as did 1 . in this study
, we revealed the production of tnf- production in lps - stimulated raw 264.7 cells by one of the eight sesquiterpene quinones , 5-epi - smenospongine ( 8) . this is the first report on the modulation of tnf- production by sesquiterpene quinones . from the comparison of structures 18 ,
it is suggested that the cis - decaline ring and a primary amine in the benzoquinone ring are necessary for the activity of 8 .
as we previously reported , compounds 3 to 8 induced the production of il-8 by pma - stimulated hl-60 cells . in this study
, we investigated their actions on tnf- produced by lps - stimulated mouse macrophage cell lines .
compound 8 induced tnf- production . however , there was no influence of the other compounds .
this may have been associated with the different actions of these compounds related to variations in receptors , signal molecules , and transcription factors in the production process of il-8 and tnf- as inflammatory cytokines .
therefore , the results of our experiment suggest that individual inflammatory cytokines can be controlled ; these compounds should be further developed in the future .
eight sesquiterpene quinones : ilimaquinone ( 1 ) , smenospongidine ( 3 ) , smenospongiarine ( 5 ) , smenospongine ( 7 ) , and their corresponding 5-epimers 2 , 4 , 6 , and 8 , isolated from the palauan marine sponge hippospongia sp . , were examined regarding their effects on tnf- production in lps - stimulated raw 264.7 cells . 
 5-epi - smenospongine ( 8) promoted the production of tnf- to a level three times greater than the control at 10 m , but compounds 17 did not show apparent activity . 
 the results suggest that the cis - decaline ring and a primary amine in the benzoquinone ring are necessary for activity . 
 this is the first study to report the modulation of tnf- production by a sesquiterpene quinone .