Flavonoid-Drug Interactions: Effects of Flavonoids on ABC ...
Flavonoid-Drug Interactions: Effects of Flavonoids on ABC ...
Flavonoid-Drug Interactions: Effects of Flavonoids on ABC ...
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<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>-<str<strong>on</strong>g>Drug</str<strong>on</strong>g> <str<strong>on</strong>g>Interacti<strong>on</strong>s</str<strong>on</strong>g>:<br />
<str<strong>on</strong>g>Effects</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s <strong>on</strong> <strong>ABC</strong> Transporters<br />
Marilyn E. Morris, Ph.D.<br />
Department <str<strong>on</strong>g>of</str<strong>on</strong>g> Pharmaceutical Sciences
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s<br />
Basic Structure:<br />
Subclasses:<br />
7<br />
6<br />
8<br />
A<br />
5<br />
1<br />
O<br />
C<br />
4<br />
2<br />
3<br />
2’ 3’<br />
B 4’<br />
5’<br />
6’<br />
‣The most abundant<br />
polyphenols present in<br />
human diet<br />
(vegetables, fruits, red<br />
wine and tea)<br />
O<br />
O<br />
O<br />
O<br />
flav<strong>on</strong>es<br />
O<br />
O<br />
OH<br />
flav<strong>on</strong>ols<br />
O<br />
O<br />
flavan<strong>on</strong>es<br />
O<br />
is<str<strong>on</strong>g>of</str<strong>on</strong>g>lav<strong>on</strong>es<br />
chalc<strong>on</strong>es
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s<br />
‣ Epidemiological studies:<br />
reduced risk <str<strong>on</strong>g>of</str<strong>on</strong>g> cancer, cor<strong>on</strong>ary heart disease,<br />
and osteoporosis<br />
‣ Biochemical and Pharmacological activities:<br />
anti-oxidant;<br />
anti-viral;<br />
anti-carcinogenic;<br />
anti-inflammatory;<br />
anti-angiogenic;<br />
anti-estrogenic (estrogenic).
‣ Toxicity:<br />
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s Have Little Toxicity<br />
• L<strong>on</strong>g history <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>sumpti<strong>on</strong> with excepti<strong>on</strong>al safety record;<br />
• Extremely large doses used in animal studies;<br />
Acute LD 50 for rats: 2 g / kg BW by direct injecti<strong>on</strong> into<br />
blood.<br />
“The margin <str<strong>on</strong>g>of</str<strong>on</strong>g> safety for the therapeutic use <str<strong>on</strong>g>of</str<strong>on</strong>g> flav<strong>on</strong>oids<br />
in humans, therefore, is very large and probably not<br />
surpassed by any other drug in current use”<br />
Havsteen, (2002), Pharmacology and Therapeutics 96:67-202.
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g> Products
Herbal Use in Select Populati<strong>on</strong>s<br />
• HIV infected patients<br />
(Fairfield etal Arch Intern Med 158:2257-2264, 1998)<br />
– 68% <str<strong>on</strong>g>of</str<strong>on</strong>g> patients used herbs, vitamin, dietary supplements<br />
– C<strong>on</strong>sumed herbal remedies to boost immunity, prevent<br />
nausea, diarrhea, or weight loss, relieve stress or<br />
depressi<strong>on</strong>.<br />
• Post-menopausal women<br />
(Mahady et al. Menopause 10:65-72, 2003)<br />
– Botanical dietary supplements used by 79% (395/500) <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
post-menopausal women within the last year.<br />
• Comm<strong>on</strong>ly used supplements include Soy (42%), green tea (35%),<br />
Chamomile (21%), Ginkgo (20%), Ginseng (18%), Echinacea<br />
(15%), & SJW (7%).
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g> Products<br />
Do not need FDA approval<br />
<str<strong>on</strong>g>Drug</str<strong>on</strong>g> interacti<strong>on</strong>s with c<strong>on</strong>venti<strong>on</strong>al drugs<br />
have not been evaluated
<strong>ABC</strong> Proteins<br />
• ATP binding cassette (<strong>ABC</strong>) superfamily<br />
P-glycoprotein (MDR1, <strong>ABC</strong>B1)<br />
Multidrug Resistance Associated Proteins (MRP,<br />
<strong>ABC</strong>C)<br />
Breast Cancer Resistance Protein (BCRP, <strong>ABC</strong>G2)<br />
• Efflux molecules out <str<strong>on</strong>g>of</str<strong>on</strong>g> cells<br />
• Tumor → multi-drug resistance<br />
• Present in the liver, kidney, BBB,<br />
gastrointestinal tract where important<br />
for drug dispositi<strong>on</strong><br />
in<br />
out
Hepatocyte<br />
OCT1<br />
SMALL<br />
ORGANIC<br />
CATIONS<br />
OAT<br />
ORGANIC<br />
ANIONS<br />
MONOVALENT<br />
BILE SALTS<br />
NTCP<br />
BULKY ORGANIC<br />
COMPOUNDS<br />
OATP<br />
GSH<br />
E<br />
R<br />
MDR1<br />
MRP 2<br />
MRP 2<br />
MRP 3<br />
MRP1<br />
MDR3<br />
PHOSPHATIDYL<br />
- CHOLINE<br />
MRP 6<br />
BSEP/SPGP<br />
BCRP<br />
©MM 98<br />
NTCP<br />
MONOVALENT<br />
BILE SALTS<br />
Michael Müller
Intestine<br />
Transporters<br />
• absorpti<strong>on</strong><br />
• efflux<br />
apical<br />
OATP3 OCT1<br />
MCT1 CNT<br />
PEPT1<br />
MRP2<br />
BCRP<br />
MDR1<br />
Metabolism<br />
CYP<br />
UGT<br />
GST<br />
PST<br />
Transporters<br />
basolateral<br />
MRP3<br />
MRP3<br />
MCT1<br />
MRP1<br />
Sandy K Pang
<strong>ABC</strong> Transporter Expressi<strong>on</strong> in the Liver and<br />
Gastrointestinal Tract<br />
‣High expressi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
MDR1, MRP2 and BCRP<br />
in the liver<br />
‣Expressi<strong>on</strong> throughout<br />
the gastrointestinal tract<br />
Dietrich et al, Gut 2003,<br />
52:1788
‣ Two homologous<br />
halves<br />
‣ Each c<strong>on</strong>sists <str<strong>on</strong>g>of</str<strong>on</strong>g>:<br />
6 TM<br />
1 ATP binding site<br />
‣ Substrate binding sites<br />
are located in TMs<br />
P-glycoprotein<br />
Broad substrate specificity:<br />
anthracyclines, Vinca alkaloids, epipodophyllotoxins and taxol<br />
cyclosporine, digoxin, verapamil etc.<br />
One <str<strong>on</strong>g>of</str<strong>on</strong>g> the major mechanisms for cancer MDR and<br />
drug-drug, drug-food interacti<strong>on</strong>s.
General Study Design<br />
‣ In vitro studies- sensitive (no expressi<strong>on</strong>) and<br />
overexpressing cell lines (characterized) examining<br />
accumulati<strong>on</strong> or flux<br />
‣In vitro studies- effects <strong>on</strong> the cytotoxicity <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
chemotherapeutic drugs<br />
‣In vitro studies- mechanism <str<strong>on</strong>g>of</str<strong>on</strong>g> interacti<strong>on</strong>; additive<br />
effects; SAR/QSAR<br />
‣In vivo studies in animals
(% <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>trol)<br />
3 H-DNM accumulati<strong>on</strong><br />
(% <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>trol)<br />
3 H-DNM Accumulati<strong>on</strong> in MCF-7 cells<br />
Verapamil<br />
Silymarin<br />
Phloretin<br />
Morin<br />
Biochanin A<br />
200<br />
150<br />
100<br />
50<br />
C<strong>on</strong>trol<br />
0<br />
MCF-7/sensitive<br />
MCF-7/ADR<br />
400<br />
300<br />
200<br />
100<br />
0<br />
***<br />
***<br />
***<br />
***<br />
***<br />
3 H-DNM accumulati<strong>on</strong><br />
Verapamil<br />
Silymarin<br />
Phloretin<br />
Morin<br />
Biochanin A<br />
C<strong>on</strong>trol<br />
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g> c<strong>on</strong>centrati<strong>on</strong>: 50 µM, Verapamil c<strong>on</strong>centrati<strong>on</strong>: 100 µM<br />
Data expressed as mean ±SD, N= 9-12; ***: p < 0.001
Increase <str<strong>on</strong>g>of</str<strong>on</strong>g> 3 H-DNM accumulati<strong>on</strong> in P-gp<br />
Positive Cells Is <str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g> C<strong>on</strong>centrati<strong>on</strong><br />
Dependent<br />
3 H-DNM accumulati<strong>on</strong><br />
(% <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>trol)<br />
1400 Biochanin A<br />
1200<br />
Morin<br />
Phloretin<br />
1000<br />
Silymarin<br />
800<br />
600<br />
Minimal C<strong>on</strong>c. for significant change:<br />
400<br />
200<br />
Biochanin A and morin: 20-30 µM<br />
Phloretin and silymarin: 30-50 µM<br />
0<br />
0 20 40 60 80 100 120<br />
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g> c<strong>on</strong>centrati<strong>on</strong> (µM)<br />
DNM accumulati<strong>on</strong> was determined in MDA435/LCC6MDR1 cells
Increase <str<strong>on</strong>g>of</str<strong>on</strong>g> Doxorubicin Cytotoxicity by<br />
Biochanin A<br />
Fracti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> cell growth<br />
1<br />
IC 50 =30.2 µM<br />
IC 50 =0.80µM<br />
0<br />
0.001 0.01 0.1 1 10 100 1000<br />
C<strong>on</strong>centrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> doxorubicin (µM)<br />
C<strong>on</strong>trol<br />
10 µM biochanin A<br />
30 µM biochanin A<br />
50 µM biochanin A<br />
100 µM biochanin A<br />
Doxorubicin cytotoxicity<br />
was determined in<br />
MDA435/LCC6MDR1 cells
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>-P-gp <str<strong>on</strong>g>Interacti<strong>on</strong>s</str<strong>on</strong>g><br />
Mechanisms:<br />
‣Biochanin A is not a substrate<br />
‣<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s affect P-gp ATPase activity or the P-gp<br />
ATPase activity induced by verapamil<br />
‣ Some flav<strong>on</strong>oids can inhibit P-gp ATP and/or substrate<br />
binding<br />
Bifuncti<strong>on</strong>al binding interacti<strong>on</strong>s with nucleotide<br />
binding domains at ATP and vicinal substrate binding site<br />
(DiPietro et al., 2002)<br />
‣No effect <strong>on</strong> P-gp expressi<strong>on</strong> in MCF-7/ADR cells or<br />
human hepatocytes following l<strong>on</strong>ger incubati<strong>on</strong>s for the<br />
flav<strong>on</strong>oids and c<strong>on</strong>centrati<strong>on</strong>s examined
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>-<str<strong>on</strong>g>Drug</str<strong>on</strong>g> <str<strong>on</strong>g>Interacti<strong>on</strong>s</str<strong>on</strong>g><br />
flav<strong>on</strong>e + paclitaxel in rats<br />
quercetin + paclitaxel in rats<br />
20 mg/kg flav<strong>on</strong>e<br />
10 mg/kg flav<strong>on</strong>e<br />
2 mg/kg flav<strong>on</strong>e<br />
c<strong>on</strong>trol<br />
10 mg/kg quercetin<br />
2 mg/kg quercetin<br />
c<strong>on</strong>trol<br />
Choi et al. (2004) Int J Pharm 275: 165-170<br />
Choi et al. (2004) Eur J Pharm Biopharm 57: 313-8
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>-<str<strong>on</strong>g>Drug</str<strong>on</strong>g> <str<strong>on</strong>g>Interacti<strong>on</strong>s</str<strong>on</strong>g><br />
quercetin + cyclosporine in pigs<br />
phellamurin + cyclosporine in rats<br />
Cyclosporin plasma<br />
C<strong>on</strong>centrati<strong>on</strong> (ng/ml)<br />
+quercetin<br />
c<strong>on</strong>trol<br />
Cyclosporin blood<br />
C<strong>on</strong>centrati<strong>on</strong> (ng/ml)<br />
c<strong>on</strong>trol<br />
+phellamurin<br />
AUC 0-3 : 56%<br />
Cmax: 47%<br />
Hsiu et al. (2002) Life Sciences 72:227-235<br />
AUC: 56%<br />
Cmax: 77%<br />
Chen et al. (2002) Planta Med 68:138-141
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>-<str<strong>on</strong>g>Drug</str<strong>on</strong>g> <str<strong>on</strong>g>Interacti<strong>on</strong>s</str<strong>on</strong>g><br />
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>-drug interacti<strong>on</strong>s could occur up<strong>on</strong> coadministrati<strong>on</strong><br />
but appear to be substrate dependent (and will be flav<strong>on</strong>oid<br />
dependent)<br />
However, other factors (for example, other transporters) may<br />
be important – there may be poor predicti<strong>on</strong> if <strong>on</strong>ly based <strong>on</strong> their<br />
interacti<strong>on</strong> with P-glycoprotein and CYP3A4
Multidrug Resistance-Associated Protein 1<br />
(MRP1, <strong>ABC</strong>C1)<br />
MRP1 is a 190-kDa protein<br />
encoded by the MRP1 gene.<br />
Expressed in most normal tissues<br />
in the human body and in several<br />
types <str<strong>on</strong>g>of</str<strong>on</strong>g> tumors such as lung<br />
carcinoma, myeloid leukemia,<br />
neuroblastoma, and breast cancer<br />
Substrates <str<strong>on</strong>g>of</str<strong>on</strong>g> MRP1:<br />
• Endogenous substrates: leukotriene C 4 , glutathi<strong>on</strong>e disulfide, steroid<br />
glucur<strong>on</strong>ides (17β-estradiol 17-β-D-glucur<strong>on</strong>ide)<br />
• Exogenous substrates: daunomycin, vinca alkaloid (vinblastine),<br />
methotrexate, fluorouracil, chlorambucil, calcein, drug c<strong>on</strong>jugates
Involvement <str<strong>on</strong>g>of</str<strong>on</strong>g> GSH in MRP1-mediated transport<br />
ATP<br />
GSSG<br />
MRP1<br />
oxidative<br />
stress<br />
GSH<br />
(reduced)<br />
GSTase<br />
ADP + Pi<br />
GSSG<br />
(oxidized)<br />
GSH<br />
reductase<br />
GSH<br />
c<strong>on</strong>jugate<br />
ATP<br />
ADP + Pi<br />
endogenous<br />
or exogenous<br />
compound<br />
GSH<br />
vincristine<br />
ADP + Pi<br />
ATP<br />
MRP1<br />
GSH<br />
GS-X<br />
MRP1<br />
GSH<br />
+<br />
vincristine<br />
Qingcheng Mao
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s increase the accumulati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> 3 H-VBL in<br />
Panc-1 Cells<br />
700<br />
600<br />
**<br />
C<strong>on</strong>trol<br />
Positive c<strong>on</strong>trol<br />
Flav<strong>on</strong>ol<br />
Flav<strong>on</strong>e<br />
Flavanol<br />
Is<str<strong>on</strong>g>of</str<strong>on</strong>g>lav<strong>on</strong>e<br />
3 H-VBL % Accumulati<strong>on</strong><br />
500<br />
400<br />
300<br />
200<br />
**<br />
*<br />
**<br />
**<br />
** ** **<br />
**<br />
100<br />
0<br />
C<strong>on</strong>trol Verapamil Kaempferol Morin Quercetin Phloretin Chalc<strong>on</strong>e Siymarin Biochanin-A Genistein<br />
* p < 0.05<br />
** p < 0.01<br />
Nguyen et al, J Pharm Sci 2003
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s that have no effect <strong>on</strong> the accumulati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 3 H-VBL in Panc-1 cells<br />
500<br />
400<br />
C<strong>on</strong>trol<br />
Positive c<strong>on</strong>trol<br />
Flav<strong>on</strong>e<br />
Flav<strong>on</strong>ol<br />
Flav<strong>on</strong><strong>on</strong>es<br />
Flavanol<br />
Is<str<strong>on</strong>g>of</str<strong>on</strong>g>lav<strong>on</strong>e<br />
300<br />
200<br />
C<strong>on</strong>trol<br />
Verapamil<br />
Apigenin<br />
ChrysinDiosminLuteolinGalanginMyricetin<br />
Rutin<br />
Hesperetin<br />
NaringeninNaringin<br />
100<br />
0<br />
Epigallocatechin<br />
Daizdein<br />
3 H-VBL % Accumulati<strong>on</strong>
Inhibitory c<strong>on</strong>stants for 3 H-LTC4<br />
transport in MRP1 membrane vesicles<br />
FLAVONOID<br />
myricetin<br />
Ki (µM)<br />
13.3 ± 2.7 (SD)<br />
quercetin 8.1 ± 1.7<br />
naringenin<br />
20.8 ± 6.4<br />
(+ GSH)<br />
kaempferol 2.4 ± 1.6<br />
apigenin (+GSH) 4.9 ± 0.7<br />
Leslie et al., Mol Pharmacol, 2001
Mechanisms involved in MRP1<br />
Inhibiti<strong>on</strong><br />
‣Decreased intracellular GSH appears to be important for some,<br />
but not all, flav<strong>on</strong>oids<br />
‣No effects <strong>on</strong> glutathi<strong>on</strong>e S-transferase were observed<br />
‣ No effects <strong>on</strong> the expressi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> MRP1 were seen with l<strong>on</strong>gerterm<br />
incubati<strong>on</strong>s<br />
‣Significant effects <strong>on</strong> MRP1 ATPase activity<br />
‣Likely not substrates<br />
‣Binding at a substrate or ATP domain is likely also involved
Breast Cancer Resistance Protein (BCRP)<br />
A new member <str<strong>on</strong>g>of</str<strong>on</strong>g> <strong>ABC</strong> transporter superfamily;<br />
Also known as <strong>ABC</strong>P (<strong>ABC</strong> transporter in placenta),<br />
MXR (mitoxantr<strong>on</strong>e-resistance protein)<br />
<strong>ABC</strong>G2 (the 2nd family <str<strong>on</strong>g>of</str<strong>on</strong>g> <strong>ABC</strong> subgroup G)<br />
Broad substrate specificity;<br />
mitoxantr<strong>on</strong>e, topoisomerase I inhibitors, methotrexate, topotecan<br />
zidovudine, lamivudine, flavopiridol, sulfate c<strong>on</strong>jugates, omeprazole<br />
genistein
Breast Cancer Resistance Protein (BCRP)<br />
Expressi<strong>on</strong> in tumors:<br />
• leukemia: AML<br />
• solid tumors: col<strong>on</strong> cancer, lung cancer, myeloma,<br />
endometrial tumor, etc.<br />
Role in clinical MDR<br />
Expressi<strong>on</strong> in normal tissues:<br />
• placenta<br />
• intestine (expressi<strong>on</strong> level is higher than P-glycoprotein)<br />
• liver canalicular membrane<br />
• brain microvessels<br />
An important determinant for drug dispositi<strong>on</strong><br />
Steinbach et al. (2002) Leukemia 16: 1443-1447 Cooray et al (2002) Neuroreport 13:2059-2063<br />
Diestra et al (2002) J. Pathol. 198: 213-219 Maliepaard et al (2001) Cancer Res 61:3458-3464<br />
J<strong>on</strong>ker et al. (2000) J Natl Cancer Inst 92:1651-1656
BCRP Clinical Implicati<strong>on</strong>s<br />
• Apparent oral bioavailability : 40.0% ⇒ 97.1%<br />
With inhibitor<br />
<str<strong>on</strong>g>Effects</str<strong>on</strong>g> <strong>on</strong><br />
both P-gp and<br />
BCRP<br />
Kruijtzer, C. M. et al., J. Clin. Oncol. 20, 2943–2950, 2002
Breast Cancer Resistance Protein (BCRP)<br />
GF120918 + topotecan in P-gp knockout mice, oral administrati<strong>on</strong><br />
Plasma c<strong>on</strong>centrati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> topotecan<br />
Biliary excreti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> topotecan<br />
Topotecan c<strong>on</strong>centrati<strong>on</strong><br />
(ng/ml)<br />
c<strong>on</strong>trol<br />
GF120918<br />
Cumulative biliary<br />
topotecan (% <str<strong>on</strong>g>of</str<strong>on</strong>g> dose)<br />
GF120918<br />
c<strong>on</strong>trol<br />
J<strong>on</strong>ker et al. (2000) J Natl Cancer Inst 92:1651-1656
Investigated <str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s<br />
A total <str<strong>on</strong>g>of</str<strong>on</strong>g> 20 naturally occurring flav<strong>on</strong>oids were studied.<br />
Flav<strong>on</strong>es:<br />
apigenin<br />
chrysin<br />
luteolin<br />
Flav<strong>on</strong>ols:<br />
fisetin<br />
kaempferol<br />
morin<br />
myricetin<br />
quercetin<br />
Is<str<strong>on</strong>g>of</str<strong>on</strong>g>lav<strong>on</strong>es:<br />
biochanin A<br />
daidzein<br />
genistein<br />
Chalc<strong>on</strong>es:<br />
phloretin<br />
phloridzin<br />
Flavan<strong>on</strong>es:<br />
hesperetin<br />
naringenin<br />
silybin<br />
silymarin<br />
epigallocatechin (EGC)<br />
epigallocatechin gallate (EGCG)<br />
naringin
Mitoxantr<strong>on</strong>e Accumulati<strong>on</strong><br />
In MCF-7 Cells<br />
600<br />
500<br />
400<br />
300<br />
200<br />
100<br />
0<br />
***<br />
***<br />
***<br />
***<br />
∗∗∗<br />
***<br />
***<br />
***<br />
***<br />
*** ***<br />
∗∗∗ ∗∗∗<br />
*<br />
*<br />
***<br />
***<br />
c<strong>on</strong>trol<br />
apigenin<br />
Biochanin A<br />
chrysin<br />
daidzein<br />
EGC<br />
EGCG<br />
fisetin<br />
genistein<br />
hesperetin<br />
kaempferol<br />
luteolin<br />
morin<br />
myricetin<br />
naringenin<br />
naringin<br />
phloretin<br />
phloridzin<br />
quercetin<br />
silybin<br />
silymarin<br />
FTC<br />
MCF-7/sensitive (-BCRP)<br />
MCF-7 MX100 (+BCRP)<br />
Mitoxantr<strong>on</strong>e: 3 µM<br />
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>: 50 µM<br />
N = 6 or 7<br />
MX accumulati<strong>on</strong><br />
(% <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>trol)
Correlati<strong>on</strong> Between MX Accumulati<strong>on</strong><br />
In H460 MX20 and MCF-7 MX100 Cells<br />
Accumulti<strong>on</strong> in MCF-7 MX100<br />
500<br />
400<br />
300<br />
200<br />
100<br />
0<br />
0 100 200 300 400 500<br />
Accumulati<strong>on</strong> in H460 MX20<br />
R 2 =0.74, p < 0.05
Mitoxantr<strong>on</strong>e Cytotoxicity in<br />
MCF-7 Cells<br />
MCF-7/sensitive<br />
MCF-7 MX100<br />
compounds 10 µM 50 µM 2.5 µM 5 µM 10 µM 50 µM<br />
c<strong>on</strong>trol 5.30 ± 2.22 199 ± 19.3<br />
apigenin 3.66 ± 0.52 3.44 ± 0.35 219 ± 10.0 10.5 ±7.13*** 1.73 ± 1.42***<br />
BA 2.40 ±0.27*** 1.86 ±0.35*** 107 ± 17.6*** 30.9 ± 5.18*** 9.23 ± 2.07*** 2.19 ± 1.04***<br />
chrysin 0.95 ± 0.46*** 18.8 ± 0.06*** 6.25 ± 2.13*** 3.35 ± 1.70*** 1.13 ± 1.11***<br />
genistein 6.98 ± 0.81 148 ± 23.2 29.3 ± 6.76*** 2.29 ± 0.86***<br />
kaempferol 6.10 ± 0.96 196 ± 20.9 228 ± 13.8 0.95 ± 0.19***<br />
hesperetin 88.6 ± 20.8*** 11.6 ± 0.83*** 1.23 ± 0.16***<br />
naringenin 189 ± 11.6 163 ± 29.5 1.23 ± 0.16***<br />
silymarin 99.1 ± 50.2*** 104 ± 35.5*** 53.0 ± 7.27***<br />
FTC 2.30 ± 0.29*** 1.79 ± 1.52***<br />
N = 1 experiment performed in quadruplicate in MCF-7/sensitive cells<br />
N = 3 independent experiments performed in triplicate in MCF-7 MX100 cells
Combined <str<strong>on</strong>g>Effects</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s <strong>on</strong><br />
BCRP-mediated Transport<br />
Characterizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> dose-resp<strong>on</strong>se pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles <str<strong>on</strong>g>of</str<strong>on</strong>g> individual<br />
flav<strong>on</strong>oids and flav<strong>on</strong>oid combinati<strong>on</strong>s;<br />
Calculati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> EC 30 , EC 50 and EC 70;<br />
Analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> potential interacti<strong>on</strong>s using isobologram and<br />
Berenbaum’s interacti<strong>on</strong> index methods<br />
Equal molar c<strong>on</strong>centrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> each c<strong>on</strong>stituent is present in<br />
the combinati<strong>on</strong>s.
Dose-Resp<strong>on</strong>se Pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles for<br />
Single <str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s<br />
Fracti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
maximal increase<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
apigenin<br />
0 2 4 6 8 10<br />
C<strong>on</strong>centrati<strong>on</strong> (µM)<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
biochanin A<br />
0 2 4 6 8 10<br />
C<strong>on</strong>centrati<strong>on</strong> (µM)<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
chrysin<br />
0 1 2 3 4 5<br />
C<strong>on</strong>centrati<strong>on</strong> (µM)<br />
Fracti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
maximal increase<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
hesperetin<br />
0 10 20 30 40 50<br />
C<strong>on</strong>centrati<strong>on</strong> (µM)<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
kaempferol<br />
0 5 10 15 20 25 30<br />
C<strong>on</strong>centrati<strong>on</strong> (µM)<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
genistein<br />
0 10 20 30 40 50<br />
C<strong>on</strong>centrati<strong>on</strong> (µM)<br />
naringenin<br />
silymarin<br />
Fracti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
maximal increase<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
0 20 40 60 80 100<br />
C<strong>on</strong>centrati<strong>on</strong> (µM)<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
0 10 20 30 40 50<br />
C<strong>on</strong>centrati<strong>on</strong> (µM)
Dose-Resp<strong>on</strong>se Pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles for<br />
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g> Combinati<strong>on</strong>s<br />
Fracti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
maximal increase<br />
Fracti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
maximal increase<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
AB<br />
0 2 4 6 8 10<br />
C<strong>on</strong>centrati<strong>on</strong> (µM)<br />
<strong>ABC</strong><br />
0.0 0.5 1.0 1.5 2.0<br />
C<strong>on</strong>centrati<strong>on</strong> (µM)<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
BC<br />
0.0<br />
0.0 0.5 1.0 1.5 2.0 2.5 3.0<br />
1.2<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
C<strong>on</strong>centrati<strong>on</strong> (µM)<br />
<strong>ABC</strong>GK<br />
0.0 0.5 1.0 1.5<br />
C<strong>on</strong>centrati<strong>on</strong> (µM)<br />
AB: apigenin + biochanin A<br />
BC: biochanin A + chrysin<br />
<strong>ABC</strong>: apigenin + biochanin A + chrysin<br />
<strong>ABC</strong>GK: apigenin + biochanin A + chrysin<br />
+ genistein + kaempferol<br />
<strong>ABC</strong>GKHNS: all the eight flav<strong>on</strong>oids<br />
investigated<br />
Fracti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
maximal increase<br />
<strong>ABC</strong>GKHNS<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4<br />
C<strong>on</strong>centrati<strong>on</strong> (µM)<br />
The c<strong>on</strong>centrati<strong>on</strong> values indicate the c<strong>on</strong>centrati<strong>on</strong>s for<br />
each individual flav<strong>on</strong>oid in the combinati<strong>on</strong>
EC 50 , EC 30 , EC 70<br />
for Increasing MX Accumulati<strong>on</strong><br />
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s EC 30<br />
(µM) EC 50<br />
(µM) EC 70<br />
(µM)<br />
Apigenin (A) 0.97 ± 0.38 1.66 ± 0.55 2.86 ± 0.80<br />
Biochanin A (B) 0.70 ± 0.47 1.62 ± 1.02 3.72 ± 2.24<br />
Chrysin (C) 0.24 ± 0.07 0.39 ± 0.13 0.61 ± 0.23<br />
Genistein (G) 8.91 ± 2.35 14.9 ± 2.69 25.0 ± 2.58<br />
Hesperetin (H) 7.12 ± 1.39 12.4 ± 2.21 21.8 ± 3.59<br />
Kaempferol (K) 3.79 ± 0.33 6.04 ± 0.09 9.67 ± 0.65<br />
Naringenin (N) 17.5 ± 2.36 32.0 ± 3.22 59.1 ± 10.5<br />
Silymarin (S) 10.6 ± 1.01 33.7 ± 2.78 109 ± 28.0<br />
AB 0.39 ± 0.04 0.81 ± 0.17 1.69 ± 0.55<br />
BC 0.15 ± 0.08 0.32 ± 0.16 0.69 ± 0.32<br />
<strong>ABC</strong> 0.16 ± 0.08 0.27 ± 0.01 0.48 ± 0.09<br />
<strong>ABC</strong>GK 0.14 ± 0.07 0.23 ± 0.08 0.40 ± 0.10<br />
<strong>ABC</strong>GKHNS 0.13 ± 0.06 0.20 ± 0.10 0.34 ± 0.19<br />
• N = 3 independent experiments performed in triplicate<br />
• C<strong>on</strong>centrati<strong>on</strong>s for combinati<strong>on</strong>s indicate the c<strong>on</strong>centrati<strong>on</strong> for individual flav<strong>on</strong>oid in the combinati<strong>on</strong><br />
Zhang et al. Pharm Res, 2004
Berenbaum’s Interacti<strong>on</strong> Index Method<br />
Berenbaum’s Interacti<strong>on</strong> Index<br />
D<br />
= ∑<br />
x,<br />
I<br />
EC<br />
i<br />
x,<br />
i<br />
EC x,I<br />
: the c<strong>on</strong>centrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> the<br />
c<strong>on</strong>stituent “i” to produce x effect;<br />
D x,I<br />
: the c<strong>on</strong>centrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> the<br />
c<strong>on</strong>stituent “i” in the combinati<strong>on</strong><br />
that will produce x effect.<br />
I = 1, additive;<br />
I < 1, synergistic<br />
I > 1, antag<strong>on</strong>istic.<br />
Interacti<strong>on</strong> index<br />
2<br />
1<br />
0<br />
30 %<br />
50 %<br />
70 %<br />
AB<br />
BC<br />
<strong>ABC</strong><br />
<strong>ABC</strong>GK<br />
<strong>ABC</strong>GKHNS<br />
<str<strong>on</strong>g>Interacti<strong>on</strong>s</str<strong>on</strong>g> were additive<br />
Zhang et al. (2004) Pharm Res, 21: 1263-73
SAR and QSAR Study<br />
Objective:<br />
To identify structural elements required for potent<br />
BCRP inhibiti<strong>on</strong>;<br />
To derive a QSAR equati<strong>on</strong> for the predicti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
flav<strong>on</strong>oid-BCRP interacti<strong>on</strong> activity.
C<strong>on</strong>clusi<strong>on</strong>s<br />
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s can inhibit human BCRP with flav<strong>on</strong>oids<br />
such as chrysin, biochanin A, apigenin and<br />
benz<str<strong>on</strong>g>of</str<strong>on</strong>g>lav<strong>on</strong>e having IC50 values in the sub- or low µM<br />
range<br />
Multiple flav<strong>on</strong>oids result in additive inhibiti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
BCRP<br />
The diversity <str<strong>on</strong>g>of</str<strong>on</strong>g> flav<strong>on</strong>oids allow the determinati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> SAR and QSAR for these compounds. SAR studies<br />
indicated the importance <str<strong>on</strong>g>of</str<strong>on</strong>g> lipophilicity, the placement<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> hydroxyl groups and the 2,3 double b<strong>on</strong>d.
<str<strong>on</strong>g>Effects</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g> flav<strong>on</strong>oids <strong>on</strong> topotecan<br />
pharmacokinetics in vivo
Effect <str<strong>on</strong>g>of</str<strong>on</strong>g> GF120918 <strong>on</strong> Topotecan PK<br />
in SD Rats<br />
Animal: SD female rats (180~220 g)<br />
Dosing regimen:<br />
C<strong>on</strong>trol: vehicle: glyc<str<strong>on</strong>g>of</str<strong>on</strong>g>urol, oral<br />
Treatment: 50 mg/kg GF120918, oral<br />
3 min later, topotecan 2mg/kg, oral<br />
(in saline c<strong>on</strong>taining 5% glucose)<br />
For iv dosing: topotecan (1mg/kg)<br />
Topotecan analysis: validated HPLC method<br />
Topotecan plasma<br />
c<strong>on</strong>centrati<strong>on</strong> (ng/ml)<br />
1000<br />
c<strong>on</strong>trol<br />
GF120918 (50mg/kg)<br />
iv topotecan (1mg/kg)<br />
100<br />
10<br />
1<br />
0 200 400 600<br />
Time (min)<br />
Parameters<br />
AUC 0-360<br />
(ng/ml•min)<br />
AUC 0-∞<br />
(ng/ml·min)<br />
Tmax (min)<br />
Cmax (ng/ml)<br />
terminal T 1/2<br />
(min)<br />
F (%)<br />
C<strong>on</strong>trol (n=7)<br />
1.74 ± 0.86 (×10 4 )<br />
1.80 ± 0.89 (×10 4 )<br />
52 ± 85.3<br />
86.4 ± 42.9<br />
127 ± 20.0<br />
29.7± 14.8<br />
GF120918 (50mg/kg) (n=4)<br />
7.65 ± 3.78 (×10 4 )**<br />
7.91 ± 356 (×10 4 )**<br />
75 ± 30<br />
257 ± 154*<br />
167 ± 65.1<br />
130 ± 58.8**
Effect <str<strong>on</strong>g>of</str<strong>on</strong>g> Chrysin <strong>on</strong> Topotecan PK<br />
in SD Rats<br />
EC 50<br />
in MCF-7 MX100: 0.39± 0.13 µM<br />
substrate: mitoxantr<strong>on</strong>e<br />
Animal: SD female rats (180~220 g)<br />
Dosing regimen:<br />
C<strong>on</strong>trol: vehicle: glyc<str<strong>on</strong>g>of</str<strong>on</strong>g>urol, oral<br />
Treatment: 5 or 50 mg/kg chrysin, oral<br />
3 min later, topotecan 2mg/kg, oral<br />
(in saline c<strong>on</strong>taining 5% glucose)<br />
Topotecan plasma<br />
c<strong>on</strong>centrati<strong>on</strong> (ng/ml)<br />
100<br />
10<br />
1<br />
c<strong>on</strong>trol<br />
chrysin (5mg/kg)<br />
chrysin (50mg/kg)<br />
0 200 400 600<br />
Time (min)<br />
Parameters C<strong>on</strong>trol (n=7) Chrysin (5mg/kg) (n=3) chrysin (50mg/kg) (n=6)<br />
AUC 0-360<br />
(ng/ml•min) 1.74 ± 0.86 (×10 4 ) 1.29 ± 0.24 (×10 4 ) 0.88 ± 0.83 (×10 4 )<br />
AUC 0-∞<br />
(ng/ml·min) 1.80 ± 0.89 (×10 4 ) 1.34 ± 0.27 (×10 4 ) 0.93 ± 0.85 (×10 4 )<br />
Tmax (min) 52 ± 85.3 35.0 ± 22.9 75.0 ± 82.2<br />
Cmax (ng/ml) 86.4 ± 42.9 68.3 ±32.2 36.0 ± 37.9<br />
terminal T1/2 (min) 127 ± 20.0 139 ± 40.4 173 ± 47.7<br />
F (%) 29.7± 14.8 22.1 ± 4.47 15.3 ± 14.1
Effect <str<strong>on</strong>g>of</str<strong>on</strong>g> Chrysin <strong>on</strong> Topotecan PK<br />
in mdr1a/1b (-/-) mice<br />
Animal: mdr1a/1b (-/-) mice (23~26.5 g)<br />
Dosing regimen:<br />
C<strong>on</strong>trol: vehicle: olive oil, oral<br />
Treatment: 50 mg/kg chrysin, oral<br />
3 min later, topotecan 2mg/kg, oral<br />
(in saline c<strong>on</strong>taining 5% glucose)<br />
Topotecan plasma<br />
c<strong>on</strong>centrati<strong>on</strong> (ng/ml)<br />
100 c<strong>on</strong>trol<br />
50 mg/kg chrysin<br />
10<br />
1<br />
0.1<br />
0 100 200 300 400<br />
Time (min)<br />
Parameters<br />
C<strong>on</strong>trol (n=4)<br />
Chrysin (50mg/kg)<br />
(n=4)<br />
AUC 0-360<br />
(ng/ml·min) 4.56 ± 3.95 (×10 3 ) 4.17 ± 2.93 (×10 3 )<br />
AUC 0-∞<br />
(ng/ml·min) 5.01 ± 3.96 (×10 3 ) 4.65 ± 2.98 (×10 3 )<br />
Tmax (min) 45.0 ± 46.4 33.7 ± 18.9<br />
Cmax (ng/ml) 45.2 ± 47.3 50.8 ± 45.8<br />
terminal T1/2 (min) 63.6 ± 42.7 90.6 ± 20.5
Possible Reas<strong>on</strong>s for the In vitro<br />
and In vivo Discrepancy<br />
Metabolism<br />
Substrate dependence<br />
Species difference<br />
Inhibiti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> topotecan uptake transporter
Effect <str<strong>on</strong>g>of</str<strong>on</strong>g> 7,8-benz<str<strong>on</strong>g>of</str<strong>on</strong>g>lav<strong>on</strong>e (BF) <strong>on</strong><br />
Topotecan PK in SD Rats<br />
EC 50<br />
in MCF-7 MX100: 0.07± 0.02 µM<br />
substrate: mitoxantr<strong>on</strong>e<br />
Animal: SD female rats (180~220 g)<br />
Dosing regimen:<br />
C<strong>on</strong>trol: vehicle: glyc<str<strong>on</strong>g>of</str<strong>on</strong>g>urol, oral<br />
Treatment: 10 or 50 mg/kg BNF, oral<br />
3 min later, topotecan 2mg/kg, oral<br />
(in saline c<strong>on</strong>taining 5% glucose)<br />
Plasma c<strong>on</strong>centrati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> topotecan (ng/ml)<br />
100<br />
10<br />
1<br />
c<strong>on</strong>trol<br />
Benz<str<strong>on</strong>g>of</str<strong>on</strong>g>lav<strong>on</strong>e (10 mg/kg)<br />
Benz<str<strong>on</strong>g>of</str<strong>on</strong>g>lav<strong>on</strong>e (50 mg/kg)<br />
0 200 400 600<br />
Time (min)<br />
Parameters<br />
C<strong>on</strong>trol (n=7)<br />
benz<str<strong>on</strong>g>of</str<strong>on</strong>g>lav<strong>on</strong>e (10 mg/kg)<br />
(n=9)<br />
benz<str<strong>on</strong>g>of</str<strong>on</strong>g>lav<strong>on</strong>e (50mg/kg)<br />
(n=8)<br />
AUC 0-360<br />
(ng/ml·min) 1.74 ± 0.86 (×10 4 ) 2.04 ± 0.48 (×10 4 ) 2.50 ± 1.14 (×10 4 )<br />
AUC 0-∞<br />
(ng/ml·min) 1.80 ± 0.89 (×10 4 ) 2.15 ± 0.43 (×10 4 ) 2.57 ± 1.15 (×10 4 )<br />
Tmax (min) 52.0 ± 85.3 82.4 ± 91.4 107 ± 91.2<br />
Cmax (ng/ml) 86.4 ± 42.9 98.0 ± 45.7 101 ± 50.9<br />
terminal T1/2 (min) 127 ± 20.0 150 ± 63.6 127 ± 37.3<br />
F (%) 29.7± 14.8 35.5 ± 7.33 42.5 ± 7.09
Possible Reas<strong>on</strong>s for the In vitro<br />
and In vivo Discrepancy<br />
Metabolism<br />
Substrate dependence<br />
Species difference<br />
Inhibiti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> topotecan uptake transporter
Effect <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s <strong>on</strong> Topotecan<br />
Accumulati<strong>on</strong> in MCF-7 cells<br />
Accumulati<strong>on</strong> time: 10 min;<br />
Topotecan c<strong>on</strong>centrati<strong>on</strong>: 5 µM;<br />
Cells were harvested and<br />
s<strong>on</strong>icated<br />
Topotecan in cell lysate was<br />
assayed by HPLC<br />
Accumulati<strong>on</strong> were normalized<br />
by protein c<strong>on</strong>tent<br />
N = 4<br />
Topotecan accumulati<strong>on</strong><br />
(% <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>trol)<br />
350<br />
300<br />
250<br />
200<br />
150<br />
100<br />
50<br />
0<br />
***<br />
***<br />
c<strong>on</strong>trol<br />
10 µM PSC833<br />
10 µM FTC<br />
10 µM PSC833 + 10 µM FTC<br />
***<br />
***<br />
50 µM chrysin<br />
5 µM BF<br />
Chrysin and BF can inhibit BCRP-mediated<br />
efflux <str<strong>on</strong>g>of</str<strong>on</strong>g> topotecan<br />
MCF-7 MX100<br />
MCF-7/sensitive
Possible Reas<strong>on</strong>s for the In vitro<br />
and In vivo Discrepancy<br />
Metabolism<br />
Substrate dependence<br />
Species difference<br />
Inhibiti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> topotecan uptake transporter
Effect <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s <strong>on</strong> Topotecan<br />
Accumulati<strong>on</strong> in MDCK-bcrp1 Cells<br />
Accumulati<strong>on</strong> time: 10 min;<br />
Topotecan c<strong>on</strong>centrati<strong>on</strong>: 5 µM;<br />
Cells were harvested and<br />
s<strong>on</strong>icated<br />
Topotecan in cell lysate was<br />
assayed by HPLC<br />
Accumulati<strong>on</strong> were normalized<br />
by protein c<strong>on</strong>tent<br />
N = 4<br />
Chrysin and BF may <strong>on</strong>ly have weak<br />
inhibiti<strong>on</strong> activity <strong>on</strong> mouse bcrp1<br />
Topotecan accumulati<strong>on</strong><br />
(% <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>trol)<br />
500<br />
***<br />
***<br />
400<br />
***<br />
300<br />
200<br />
100<br />
0<br />
c<strong>on</strong>trol<br />
PSC833 (10 µM)<br />
GF120918 (10 µM)<br />
FTC (10 µM)<br />
PSC833 (10 µM)+FTC (10 µM)<br />
chrysin (50 µM)<br />
BF (5 µM)<br />
MDCK-mock<br />
MDCK-bcrp1<br />
*
Summary<br />
Chrysin and BF did not change topotecan PK in rats or mice<br />
Tentative explanati<strong>on</strong> for the discrepancy: species difference<br />
with respect to inhibiti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> topotecan<br />
(species difference not seen with mitoxantr<strong>on</strong>e)<br />
Other possibilities could not be excluded, such as involvement<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> other transporters
<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g> <str<strong>on</strong>g>Interacti<strong>on</strong>s</str<strong>on</strong>g> with <strong>ABC</strong><br />
Transporters<br />
‣<str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s are widely-present in food and herbal products.<br />
‣Inhibitory interacti<strong>on</strong>s occur with P-glycoprotein, MRP1 and<br />
BCRP. These interacti<strong>on</strong>s may be beneficial for the reversal <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
multidrug resistance in cancer. <str<strong>on</strong>g>Flav<strong>on</strong>oid</str<strong>on</strong>g>s may also increase the<br />
bioavailability and decrease the clearance <str<strong>on</strong>g>of</str<strong>on</strong>g> drugs.<br />
‣C<strong>on</strong>centrati<strong>on</strong>s achievable in vivo in the gastrointestinal tract are<br />
likely high enough to result in significant interacti<strong>on</strong>s with <strong>ABC</strong><br />
transporters. This is particularly true with respect to flav<strong>on</strong>oid<br />
c<strong>on</strong>centrati<strong>on</strong>s after herbal medicines.