Patent Abstract:
a composition is provided for chemoprevention of an oral cancer or precancerous condition , including an isolated berry preparation admixed with a bioadhesive carrier . the carrier may be a mucoadhesive gel . the berry preparation may be derived from one or more of strawberry , raspberry , red raspberry , and black raspberry . methods for producing the compositions are provided also . there are also provided methods for chemoprevention of an oral cancer or precancerous condition , utilizing the compositions of the invention . still further , methods for enhancing stability of an anthocyanin contained in the berry preparation of the invention are provided , along with methods for enhancing efficacy of the compositions .

Detailed Description:
the examples provided herein are presented in support of and to further illustrate the invention as described above , but are not to be considered as limited thereto . all references cited to herein are incorporated into the present disclosure in their entirety by reference unless otherwise specified . the following general of materials and methods applies to the examples set forth hereinafter . noveon aa1 ( nf ) was obtained from noveon , inc . ( cleveland , ohio ). carbopol 971p nf was a gift from bf goodrich specialty chemicals ( cleveland , ohio ). edetate disodium ( edta ; usp ), 2 - phenoxyethanol ( bp ), benzyl alcohol ( usp ), glycerin ( usp ), sodium hydroxide ( nf ), and formic acid ( acs reagent ) were obtained from spectrum quality products , inc . ( new brunswick , n . j .). acetonitrile ( hplc grade ) was from fisher scientific ( hampton , n . h .). reagents used for tissue explant analyses ( sodium carboxymethylcellulose , sorbitol , nacl , kcl , calcium chloride dehydrate , mgcl 2 , trizma hydrochloride ) were purchased from sigma chemical company ( st . louis , mo .). all black raspberries used in these studies were of the jewel variety ( rubus occidentalis ) and were grown at the stokes raspberry farm ( wilmington , ohio ). all berries were grown in the same part of the field , and picked at about the same degree of ripeness ( when the majority of the berries in a cluster have turned black - this occurs within a period of 1 - 2 weeks ). the berries were harvested mechanically ( with a picker ) in a total period of 4 hr , washed , and frozen at − 20 ° c . within an hour of the time of harvest . the frozen berries were subsequently freeze - dried and ground into a powder as described previously [ kresty et al ., 2001 ; castro et al ., 2002 ; xue et al ., 2001 ; huang et al ., 2002 ; rodrigo et al ., in press ; stoner et al ., 2005 ]. all berries picked during a single year were freeze - dried concurrently . the freeze - drying process ( including the entire black raspberry fruit including seeds ) resulted in very little degradation of the analyzed components of the berries ( see description below ). the freeze - dried berry preparations ( hereinafter , fbr ) were stored frozen until use . random samples of each batch of freeze - dried berries were shipped to an independent laboratory for measurement of the components to ensure that measured components did not degrade significantly during processing and storage as described above . on average , over a five year period , the variation in content of most measured components was less than 20 %. anthocyanin content in sera , saliva , and tissue explants was evaluated by an hplc - ms assay . the respective samples ( sera , saliva or tissue homogenates ) were dissolved in 90 % solvent a ( water plus 1 % formic acid ) and 10 % solvent b ( acetonitrile plus 1 % formic acid ) and then separated on a symmetry c 18 reversed - phase column and analyzed using a waters 2695 gradient hplc separation module equipped with a 996 photodiode - array ( pda ) uv / visible absorbance detector ( milford , mass .). the solvent system consisted of a step gradient from 90 % a to 50 % b over 15 minutes , and the absorption spectra were recorded from 200 - 800 nm with the inline pda detector . mass spectrometry was conducted on a quadrupole ion tunnel mass spectrometer equipped with a z - spray esi source . explant protein levels were determined by the lowry method , using bovine γ - globulin as the standard protein [ lippman et al ., 1993 ]. it was desired to evaluate the effect of ph and concentration of fbr on the efficacy of the compositions and methods of the present invention . accordingly , various mucoadhesive berry gels varying in final ph and % fbr were prepared for various analyses and in - vivo studies . five studies were completed as follows : 1 ) ph 6 . 5 gels with 5 % w / w fbr for a human pharmacokinetic study , 2 ) ph 6 . 5 gels with 5 % and 10 % w / w fbr for anthocyanin uptake studies in human mucosa explant tissue , 3 ) ph 4 . 5 , 5 . 5 , 6 . 5 , and 7 . 5 gels with 10 % w / w fbr to determine anthocyanin stability at 1 week at 4 ° c ., 25 ° c ., and 40 ° c ., 4 ) ph 3 . 5 and ph 4 . 0 gels with 10 % w / w fbr to determine anthocyanin stability over 1 month at 4 ° c . and 25 ° c ., and 5 ) ph 3 . 5 and ph 6 . 5 gels with 10 % w / w fbr to compare difference in anthocyanin uptake into human mucosa explant tissue . all gels were prepared in stainless steel vessels using a caframo stirrer model bdc - 1850 ( wiarton , ontario , canada ) with attached metal blade . to the required amount of purified water stirring in the vessel , noveon aa1 and carbopol 971p were added slowly and allowed to fully hydrate for at least 1 hr . next , glycerin , 2 - phenoxyethanol , and benzyl alcohol were added followed by edta . the gel was allowed to mix for another 1 hr . sodium hydroxide ( 2 . 5 n ) was added to raise the ph of the gel to ph 7 . 5 . placebo gels were semi - transparent and homogenous in appearance . finally , powdered fbr was added in different amounts to produce final concentrations of fbr of either 5 % or 10 % w / w . either 2 . 5 n naoh or 2 . 33 n hcl was added to adjust to the desired ph . purified water was then added to q . s . the gels to weight . gels having a final ph in the range of ph 4 . 5 to 7 . 5 had the following final concentration of excipients : noveon aa1 ( 0 . 675 % w / w ), carbopol 971p ( 0 . 788 % w / w ), glycerin ( 0 . 9 % w / w ), 2 - phenoxyethanol ( 0 . 9 % w / w ), benzyl alcohol ( 0 . 9 % w / w ), and edta ( 0 . 09 % w / w ). two adjustments were subsequently made for gels having a fmal ph of either ph 3 . 5 or 4 . 0 . first , the amounts of noveon aa1 and carbopol 971p needed to produce a final berry gel having comparable viscosity at lower ph were significantly increased . second , the concentration of all other excipients was increased by 10 % to adjust for the dilutive effects of adding powdered fbr at the level of 10 % w / w . thus , gels having a fmal ph of either ph 3 . 5 or 4 . 0 had the following final concentration of excipients : noveon aa1 ( 1 . 35 % w / w ), carbopol 971p ( 1 . 575 % w / w ), glycerin ( 1 . 0 % w / w ), 2 - phenoxyethanol ( 1 . 0 % w / w ), benzyl alcohol ( 1 . 0 % w / w ), and edta ( 0 . 1 % w / w ). all prepared gels were stored at 2 - 8 ° c . ( unless stated otherwise ), sealed and protected from light in 10 g white aluminum tubes , sealed neck with morton pe 1090 liner ( montebello packaging ; ontario , canada ). gels were characterized for ph , viscosity , osmolality , and anthocyanin content . the ph of gels was measured using an orion ph meter model 520a . gel viscosity was determined using a brookfield cone & amp ; plate rheometer model rvdv iii + ( brookfield engineering , middleboro , mass .) at 25 ° c . for 1 min at an rpm of 4 using spindle cpe - 52 . the osmolality was measured using a fiske 110 freezing - point depression osmometer . the microbial limits test & lt ; 61 & gt ; in usp 29 was used to determine the total microbial count of the gels , and for the presence of yeasts and molds . with reference to a representative embodiment of the fbr gel of the present invention as shown in table 1 , gels were prepared by adding fbr to semi - transparent and homogenous placebo gels to achieve a final fbr concentration of up to 10 % w / w . for unbuffered placebo gels , the addition of fbr resulted in a lowering of the gel ph in proportion to the amount of fbr added . for example , the addition of 10 % fbr to a placebo gel with a ph of 6 . 9 resulted in a final ph of the 10 % w / w gel of 5 . 9 . however , the ph of the 10 % w / w berry gel was easily adjusted to the desired ph . the drop of ph after the addition of fbr was due to the naturally low ph of the fbr , since a 10 % w / w slurry of the fbr in water had a ph of 4 . 3 . the addition of fbr to placebo gels resulted in a red to black homogenous gel with a viscosity target range from 10 , 000 to 20 , 000 cp . the addition of fbr to placebo gel did not significantly affect final gel viscosity . to quantify and evaluate stability of the anthocyanin composition of fbr gels prepared as described in example 1 , a reversed - phase hplc assay was developed and partially validated . the hplc assay was developed based on a previously described assay by tian et al . [ 2005 ]. for the assay , a thermoquest hplc system with a uv6000lp photodiode array detector , a water &# 39 ; s symmetry c18 column ( 3 . 9 × 150 mm , 5 μm ), and a phenomenex security guard with c18 cartridge were employed . fbr standards ( 0 - 2 mg / ml ) were prepared by dissolving fbr in aqueous 1 % formic acid ( mobile phase a ) and vortexing to completely dissolve the powder . the slightly cloudy standards were filtered through a 0 . 45 μm hydrophilic ptfe syringe filter into a hplc vial . a linear gradient ( flow rate of 1 . 0 ml / min ) of mobile phase a ( 1 % formic acid ) and mobile phase b ( 100 % acetonitrile ) was utilized at a column temperature of 40 ° c . as follows : 93 % a ( isocratic ) for 0 - 2 min , 93 % a to 89 % a ( linear gradient ) for 2 - 18 min , 89 % a to 0 % a ( linear gradient ) for 18 - 19 min , 0 % a ( isocratic ) for 19 - 25 min , 0 % a to 93 % a ( linear gradient ) for 25 - 26 min , and 93 % a ( isocratic ) for 26 - 35 min . the total run time was 35 min . the injection volume was 10 μl and the detection wavelength for the anthocyanins was 520 nm . the fbr gels were analyzed by adding 100 mg of gel to a 10 ml volumetric flask with aqueous 1 % formic acid followed by the subsequent steps as described above . with reference to the representative standard chromatogram presented in fig1 , two peaks termed fbr 1 and fbr 2 were seen . these two peaks appear to correspond to the four peaks shown in tian et al . [ 2005 ]. it was subsequently determined using lc - ms ( see below ) that fbr 1 correspond to cyanidin 3 - glucoside and cyanidin 3 - sambubioside and fbr 2 correspond to cyanidin 3 - xylosylrutinoside and cyanidin 3 - rutinoside . for initial development of the hplc assay , a 1 % formic acid mobile phase was used instead of 10 % formic acid as previously described by tian et al . to conserve the stability and integrity of the c18 column . as shown in fig2 , the standard curve for both fbr 1 and fbr 2 showed excellent linearity over the range of 50 μg / ml to 2000 μg / ml . system suitability for the assay calculated by averaging the peak areas of all standard injections showed that the relative standard deviation ( rsd ) of the assay was less than 1 %. in addition , the recovery of anthocyanins ( both fbr 1 and fbr 2 ) from the gels was greater than 99 %. initial studies indicated that lower ph and lower storage temperatures were more favorable for fbr 1 and fbr 2 peak stability . fig3 a shows the percent detected for 10 % berry gels at various ph values after 24 hr storage at 4 , 25 , and 40 ° c . for both fbr 1 and fbr 2 , there was a very strong correlation between ph storage temperatures in terms of peak retention . it is well known that anthocyanins exist at low ph as a flavylium cation , which is their naturally occurring form . the flavylium cation is highly electron deficient and intensely colored ( red or orange ) at a ph below about ph 4 . 5 . at higher phs , anthocyanins exist as either a quinoidal base , carbinol pseudobase , or the chalcone pseudobase . thus , in addition to being less stable at higher ph , the flavylium cation is known to be less stable at increased temperatures [ rubinskiene et al ., 2005 ; morais et al ., 2002 ]. subsequent stability studies were performed using four gels formulated at 3 . 5 and 4 . 0 , with and without 0 . 1 % w / w ascorbic acid as an additional anti - oxidant . the results ( see fig3 b ) demonstrate that the ph 3 . 5 gel provided excellent stability for fbr 1 ( 96 . 0 ± 0 . 8 %) and fbr 2 ( 100 . 2 ± 0 . 4 %) over a 1 month storage period at 4 ° c . gels at ph 4 , gels stored at 25 ° c ., and gels with 0 . 1 % ascorbic acid ( data not shown ) demonstrated less stability for both fbr 1 and fbr 2 . the results of the second stability study demonstrated that ph 3 . 5 provided for the greatest storage stability of fbr 1 and fbr 2 when 10 % fbr was formulated in the gel and stored at 4 ° c . next , evaluation of anthocyanin uptake into human oral mucosa from fbr gels prepared as described in example 1 was undertaken . for in - vivo studies , participation of human subjects was conducted in accordance with an irb approved protocol . none of the human subjects had a diet rich in anthocyanin compounds prior to participation in either the pharmacokinetic or tissue explant studies . for the phamacokinetic analyses , nine consenting adult volunteers dried the anterior floor of their mouth , placed 1 . 0 g of 5 % berry gel ( ph 6 . 5 ), and massaged the gel in place for 30 seconds to facilitate uptake . two minutes after gel application saliva was collected for the next three minutes . peripheral blood was drawn five minutes after gel application . following clotting , sera samples were collected , and both the sera and saliva samples were stored at − 80 ° c . until lc - ms analysis as described below . the human pharmacokinetic studies which used the 5 % berry gel ( ph 6 . 5 ) demonstrated that bioadhesive berry gels were readily absorbed into human oral mucosa ( see table 2 ). all nine participants had detectable anthocyanin levels of three anthocyanins ( cyanidin 3 - rutinoside , cyanidin 3 - xylosylrutinoside , cyanidin 3 - glucoside ) in either their saliva or blood , and 4 donors had detectable levels of two anthocyanins ( cyanidin 3 - rutinoside and cyanidin 3 - xylosylrutinoside ) in their peripheral blood . saliva from eight of the nine donors contained detectable levels of either two ( cyanidin 3 - rutinoside and cyanidin 3 - xylosylrutinoside - 4 donors ) or three anthocyanins ( 4 donors ). tissue explants , specifically human oral mucosal explants , were used to determine the in vitro effects of fbr content and ph on anthocyanin uptake . human oral tissues for the tissue explant studies were obtained from consenting volunteers who were undergoing elective oral surgery procedures . to confirm “ no pathologic diagnosis ”, a portion of each of these tissues was submitted for light microscopic evaluation . all tissue donors were systemically healthy and did not use tobacco products . tissues for explant experiments were immediately placed in an artificial saliva transport medium , which also served as the incubation medium for the gel absorption studies . the composition of the artificial saliva used for tissue transport and incubation was ( final concentrations ): sodium carboxymethylcellulose ( 0 . 5 %), sorbitol ( 165 mm ), nacl ( 14 mm ), kcl ( 16 mm ), calcium chloride dehydrate ( 1 . 0 mm ), mgcl 2 ( 0 . 63 mm ), trizma hydrochloride ( 2 . 0 mm ). tissues from eight donors were used for preliminary studies to compare the penetration of anthocyanins from the 5 % berry gel and the 10 % fbr gel , both at a final ph of 6 . 5 . in order to account for heterogeneity among human donors , tissue samples were hemisected . one tissue portion treated with 5 % and the other with 10 % fbr gels . one gram of gel ( containing either 5 % or 10 % w / w fbr ) was placed on the epithelial surface of the explant , followed by gently rubbing of the site for 30 seconds to facilitate uptake . explants were then placed into artificial saliva , incubated for 30 minutes ( 37 ° c ., 5 % co 2 ), and then frozen at − 80 ° c . until hplc - mass spectroscopy analyses as previously reported [ rodrigo et al ., in press ]. tissue preparation for hplc analyses consisted of homogenization of the entire oral mucosal specimen , removal of an aliquot for sample protein level determination , followed by the addition of collagenase type ii ( 0 . 1 mg / ml , gibco , grand island , n . y .) and 1 % formic acid . samples were then placed on a sep pack ( millipore , billerica , mass . ), eluted with methanol , and dried under argon gas . comparing the ability of 5 % relative to 10 % berry gels ( both adjusted to a ph of 6 . 5 ) to absorb into human oral mucosa explants , it was found that the 10 % berry gel delivered detectable levels of all four anthocyanin compounds ( see fig4 ) into all eight of the tissue explants evaluated . in contrast , only two anthocyanins ( cyanidin 3 - rutinoside and cyanidin 3 - xylosylrutinoside ) were identified in tissues treated with the 5 % gel formulations . additional oral mucosal explant studies were conducted to compare the effect of fbr gel ph on absorption into oral mucosal explants . tissues from eleven donors were used for these studies , and handling was as described above with the exception that all gels contained 10 % w / w fbr and were formulated at a final ph of 3 . 5 or 6 . 5 . in contrast to the human pharmacokinetic evaluations , tissue explant studies showed the presence of all four anthocyanins contained in fbr , inclusive of cyanidin 3 - sambubiocide . further , these data demonstrated approximately 2 - 3 fold higher levels of the respective anthocyanin in tissue explants relative to levels determined in either saliva or blood . as shown in table 3 , studies to compare the effect of gel ph on tissue anthocyanin uptake suggested greater penetration with the ph 6 . 5 gels . four donors &# 39 ; tissues showed increased penetration of all four anthocyanin compounds with the ph 6 . 5 relative to the ph 3 . 5 gels . notably , there were large variations that reflected both the anthocyanin under evaluation as well as the penetrability of the individual donors &# 39 ; tissues . further , depending upon the anthocyanin compound under analysis , there were between 4 to 6 tissue donors who consistently showed greater penetration with the ph 3 . 5 gel . large differences ( up to 15 - fold ) in detectable anthocyanin levels were found in the gel treated donor tissues ; findings that likely reflect the extensive heterogeneity within human tissues that affects tissue penetrative abilities . finally , although these data demonstrate trends towards enhanced tissue penetration with the higher ph 6 . 5 berry gel , due to large inter - and intra - donor standard deviations , these differences were not statistically significant . a gel substantially as described in example 1 is prepared , with the exception that a solvent - extracted fbr preparation is used . solvent extraction is conducted substantially as described in copending u . s . utility patent application ser . no . 10 / 951 , 413 . briefly , 400 grams of fbr are extracted in 4 , 000 ml of methanol or ethanol overnight at room temperature . the solvent - extracted preparations are then concentrated under vacuum , such that the concentrated , solvent - extracted frb preparation typically represents approximately 55 % of the starting freeze - dried material . the concentrated solvent - extracted fbr preparations is then incorporated into a mucoadhesive gel substantially as described in example 1 . in another embodiment of the present invention , a solvent - extracted fbr preparation is used to formulate a mucoadhesive gel preparation . solvent extraction is conducted substantially as described in hecht et al . [ in press ]. briefly , fbr ( 25 g ) prepared as described in example 1 is sequentially extracted with pentane , methylene chloride , absolute ethanol , and water . the fbr preparation is placed in a soxhlet extraction thimble and extracted with 400 ml pentane for 16 hr . fresh pentane ( 400 ml ) is added , and the procedure repeated for 16 hr . the process is repeated with the same volumes of methylene chloride and absolute ethanol . next , the residue is removed from the thimble and sonicated 3 times with 100 ml aliquots of water ( 30 min . sonications ). extracts from each solvent extraction are combined , and the solvents removed by rotary evaporation . in the case of the water - sonicated residue , water is removed by lyophilization . the solvent - extracted frb preparation typically represents approximately 18 % of the starting freeze - dried material . the concentrated solvent - extracted fbr preparation is then incorporated into a mucoadhesive gel substantially as described in example 1 . a different solvent extraction procedure is used to formulate a mucoadhesive fbr gel preparation . solvent extraction is conducted substantially as described in hecht et al . [ in press ]. briefly , fbr ( 25 g ) prepared as described in example 1 is placed in a 1 l erlenmeyer flask and sequentially extracted with stirring at room temperature with 3 400 ml portions each of pentane , methylene chloride , absolute ethanol , and water . an explosion - proof mechanical stirrer ( caframo , ltd ., wiarton , ontario , canada ) is used . each extraction is carried out for 16 hr . the solvent - extracted frb preparation typically represents approximately 18 % of the starting freeze - dried material . the concentrated solvent - extracted fbr preparation is then incorporated into a mucoadhesive gel substantially as described in example 1 . a mucoadhesive fbr gel preparation is prepared using ethanol extraction substantially as described in hecht et al . [ in press ] and in examples 6 - 7 . briefly , fbr ( 25 g ) prepared as described in example 1 is placed in a 1 l erlenmeyer flask and extracted with stirring at room temperature with 3 400 ml portions of absolute ethanol . each extraction is carried out for 16 hr . the solvent - extracted frb preparation typically represents approximately 50 % of the starting freeze - dried material . the concentrated solvent - extracted fbr preparations are then incorporated into a mucoadhesive gel substantially as described in example 1 . a 5 kg batch of the 10 % fbr gel , ph 3 . 5 was prepared using the formula described in table 1 . the gel was placed in aluminum tubes , sealed neck with morton pe 1090 liner ( montebello packaging ; ontario , canada ) tubes and stored under controlled conditions at 4 ° c . ( 2 - 8 ° c .). as determined by the microbial limits test & lt ; 61 & gt ; in usp 29 , the total microbial count of the gel was 255 colony forming units ( cfu )/ g and was found to be free of escherichia coli , salmonella , staphylococcus aureus , pseudomonas aeruginosa . the viscosity was measured using a brookfield rvdv iii cone & amp ; plate rheometer using spindle 52 at 4 rpm at 25 ° c . for 1 min . the osmolality was measured using a fiske 110 freezing - point depression osmometer . the ph was measured using a orion ph meter model 520a . after 6 months storage at 4 ° c ., the gel was found to contain no mold . yeast present in the gel was identified as candida colliculosa and was present at 300 cfu / g as determined by the microbial limits test & lt ; 61 & gt ; in usp 29 . a 10 % fbr gel was prepared substantially as described in example 9 , with the ph adjusted to 3 . 5 . fourteen patients with either stage i , ii , or iii dysplasia and ten control patients were treated with 2 grams of the gel per lesion per day for a period of 42 days . the control participants applied the same amount to gel to a specified site ( lateral tongue ) that consisted of clinically normal tissue . patients were monitored for clinical assessment and light microscopic diagnosis to determine lesion size , diminished leukoplakia ( white appearing tissue ) or erythroplakia ( velvet red appearing tissue ). no participant experienced any observable adverse effects , such as mucositis and / or delayed wound healing . microscopic evaluation revealed that 6 of the 14 dysplasia patients exhibited a decrease in disease severity , assessed by histologic grade . the present disclosure therefore shows that an effective composition is provided for the chemoprevention of certain types of cancer , especially oral cancers . furthermore , the concentrating processes described herein concentrate the berries bioactive constituents at least ten - fold , introducing a greater chemopreventive impact within a particular gel formulation . the local delivery formulations described for the compositions of the present invention provide a significant pharmacologic benefit ; specifically the ability to obtain therapeutically relevant local levels as well as rapid absorption kinetics for systemic benefits , without development of systemic complications . anthocyanin detection in the saliva following topical gel application supports the premise that bioadhesive gels can provide field coverage throughout the mouth . the surprising detection of anthocyanins in peripheral blood within 5 minutes of fbr gel application provides even more compelling evidence that the gel formulation efficiently delivers bioactive anthocyanin compounds to the target tissue site . in addition , the explant studies suggested that gel formulations provide a pharmacologic advantage to the target tissue site ( higher anthocyanin levels in explants relative to either saliva or blood ). although it is difficult to compare these results to those of several human studies investigating the oral absorption of much larger quantities of anthocyanins in food or beverages [ kay et al ., 2005 ; bitsch et al ., 2004 ; matsumoto et al ., 2001 ] it is fair to conclude that the transmucosal absorption of anthocyanins from the berry gel was relatively rapid and potentially greater from the mouth compared to the oral absorption achieved by dietary supplementation . the foregoing description of the preferred embodiment of this invention has been presented for purposes of illustration and description . it is not intended to be exhaustive or to limit the invention to the precise form disclosed . obvious modifications or variations are possible in light of the above teachings . the embodiment was chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated . all such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly , legally , and equitably entitled . bitsch i , janssen m , netzel m , strass g , frank t . bioavailability of anthocyanidin - 3 - glycosides following consumption of elderberry extract and blackcurrant juice . int j clin pharmacol ther . 2004 , 42 ( 5 ): 293 - 300 . braakhuis b j , tabor m p , leemans c r , van der waal i , snow g b , brakenhoff r h . second primary tumors and field cancerization in oral and oropharyngeal cancer : molecular techniques provide new insights and definitions . head neck 24 : 198 - 206 ( 2002 ). casto b c , kresty l a , kraly c l , pearl d k , knobloch t j , schut h a , stoner g d , mallery s r , weghorst c m . chemoprevention of oral cancer by black raspberries . anticancer res 22 : 4005 - 4016 ( 2002 ). hecht s s , huang c , stoner g d , li j , kenney p m j , sturla s j , carmella s g . identification of cyanidin glycosides as constituents of freeze - dried black raspberries which inhibit anti - benzo [ a ] pyrene - 7 , 8 - diol - 9 , 10 - epoxide induced nfκb and ap - 1 activity . in press : carcinogenesis . hu c , zawistowski j , ling w , kitts d d . black rice ( oryza sativa l . indica ) pigmented fraction suppresses both reactive oxygen species and nitric oxide in chemical and biological model systems . j agric food chem 51 : 5271 - 5277 ( 2003 ). huang c , huang y , li j , hu w , aziz r , tang m - s , sun n , cassady j , stoner g d . inhibition of benzo ( a ) pyrene diol - epoxide - induced transactivation of activated protein 1 and nuclear factor κb by black raspberry extracts . cancer res 62 : 6857 - 6863 ( 2002 ). jemal a . murray t , ward e , samuels a , tiwari r c , ghafoor a , feuer e j , thun m j . cancer statistics , 2005 . ca a cancer journal for clinicians . 55 : 10 - 11 ( 2005 ). katsube n , iwashita k , tsushida t , yamaki k , kobori m . induction of apoptosis in cancer cells by bilberry ( vaccinium myrtillus ) and the anthocyanins . j agric food chem 51 : 68 - 75 ( 2003 ). kay c d , mazza g j , holub b j . anthocyanins exist in the circulation primarily as metabolites in adult men . j nutr . 2005 . 135 ( 11 ): 2582 - 8 . kresty a , morse m a , morgan c , carlton p s , lu j , gupta a , blackwood m , stoner g d . chemoprevention of esophageal tumorigenesis by dietary administration of lyophilized black raspberries . cancer res 61 : 6112 - 6119 ( 2001 ). lippman s m , batsakis j g , toth b b et al . comparison of low - dose isoretinoin with beta - carotene to prevent oral carcinogenesis . n eng j med 328 : 15 - 20 , 1993 . liu m , li x q , weber c , lee c y , brown j , liu r h . antioxidant and antiproliferative activities of raspberries . j agric food chem 50 : 2926 - 2930 ( 2002 ). malone j p , stephens j a , grecula j c , rhoades c a , ghaheri b a , schuller d e . disease control , survival , and functional outcome after multimodal treatment for advanced - state tongue base cancer . head neck 26 : 561 - 572 ( 2004 ). matsumoto h , inaba h , kishi m , tominaga s , hirayama m , tsuda t . orally administered delphinidin 3 - rutinoside and cyanidin 3 - rutinoside are directly absorbed in rats and humans and appear in the blood as the intact forms . j agric food chem . 2001 49 ( 3 ): 1546 - 51 . morais h , ramos c , forgacs e , cserhati t , oliviera j . influence of storage conditions on the stability of monomeric anthocyanins studied by reversed - phase high - performance liquid chromatography . j chromatogr b analyt technol biomed life sci . 2002 , 25 ; 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