Quercetin Significantly Inhibits the Metabolism of Caffeine, a Substrate of Cytochrome P450 1A2 Unrelated to <svg  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2812004pt" id="M1" height="16.6263pt" version="1.1" viewBox="-0.0657574 -16.3451 89.8386 16.6263" width="89.8386pt"><g transform="matrix(.018,0,0,-0.018,0,0)"><path id="g113-68" d="M645 631C614 643 545 666 457 666C215 666 23 519 23 283C23 90 158 -16 337 -16C412 -16 489 2 522 10C543 39 590 127 606 167L580 181C519 89 459 18 348 18C201 18 122 136 122 287C122 464 244 632 435 632C544 632 602 595 608 472L639 475C643 526 645 581 645 631Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="668" vert-adv-y="668"/></g><g transform="matrix(.018,0,0,-0.018,11.946,0)"><path id="g113-90" d="M640 650H413L406 622L438 617C475 611 483 605 463 571C422 503 346 400 296 333C264 403 215 529 199 575C189 604 191 614 228 618L262 622L271 650H30L23 622C90 615 97 609 119 553L212 321C222 295 223 285 218 259L193 127C176 39 167 33 82 28L76 0H350L356 28C266 36 257 40 275 127L303 266C308 290 314 302 328 322C396 418 454 493 498 546C551 610 565 616 631 622L640 650Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="652" vert-adv-y="652"/></g><g transform="matrix(.018,0,0,-0.018,22.357,0)"><path id="g113-81" d="M600 480C600 590 528 650 384 650H143L137 622C222 614 225 607 210 531L130 127C113 41 106 36 23 28L17 0H294L300 28C204 36 195 42 212 127L243 284L314 263C327 263 339 263 352 264C465 271 600 337 600 480ZM508 481C508 351 402 304 329 304C289 304 265 311 250 317L295 559C302 594 310 606 323 611C335 616 350 619 367 619C455 619 508 573 508 481Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="617" vert-adv-y="617"/></g><g transform="matrix(.018,0,0,-0.018,33.399,0)"><path id="g113-50" d="M384 0V27C293 34 287 42 287 114V635C232 613 172 594 109 583V559L157 557C201 555 205 550 205 499V114C205 42 199 34 109 27V0H384Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="480" vert-adv-y="480"/></g><g transform="matrix(.018,0,0,-0.018,41.983,0)"><path id="g113-66" d="M686 28C612 35 607 44 591 112C563 234 541 360 519 489L489 666L457 658L147 121C100 40 89 36 24 28L17 0H240L250 28C168 34 159 41 190 101L262 237H482C495 180 503 137 510 91C517 47 514 35 441 28L433 0H677L686 28ZM475 280H285L429 541H431L475 280Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="703" vert-adv-y="703"/></g><g transform="matrix(.018,0,0,-0.018,54.549,0)"><path id="g113-51" d="M412 140C382 77 369 73 315 73H129L270 222C362 320 402 379 402 466C402 571 322 635 234 635C177 635 130 609 99 576L42 495L64 475C90 514 133 568 201 568C274 568 318 519 318 435C318 349 255 267 193 193C144 135 87 78 32 23V0H405C417 45 427 89 440 131L412 140Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="480" vert-adv-y="480"/></g><g transform="matrix(.013,0,0,-0.013,63.133,-7.899)"><path id="g190-43" d="M364 493V518L231 520L258 659L234 665L176 533L55 613L40 592L144 490L42 396L56 374L178 451L248 321L271 330L232 468L364 493Z"/><glyph.data ascent="989" descent="-360" horiz-adv-x="404" vert-adv-y="404"/></g><g transform="matrix(.018,0,0,-0.018,68.867,0)"><use xlink:href="#g113-50"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="480" vert-adv-y="480"/></g><g transform="matrix(.018,0,0,-0.018,77.451,0)"><use xlink:href="#g113-68"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="668" vert-adv-y="668"/></g></svg>  (−2964G>A) and <svg  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-5.2715pt" id="M2" height="21.6166pt" version="1.1" viewBox="-0.0657574 -16.3451 25.3778 21.6166" width="25.3778pt"><g transform="matrix(.013,0,0,-0.013,0,-7.899)"><use xlink:href="#g190-43"/><glyph.data ascent="989" descent="-360" horiz-adv-x="404" vert-adv-y="404"/></g><g transform="matrix(.018,0,0,-0.018,5.734,0)"><use xlink:href="#g113-50"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="480" vert-adv-y="480"/></g><g transform="matrix(.018,0,0,-0.018,14.318,0)"><path id="g113-71" d="M584 650H137L131 622C214 614 217 612 200 521L125 127C109 41 101 35 23 28L17 0H288L294 28C201 35 193 42 209 128L242 309H348C440 309 442 300 443 226H471L510 422H482C452 354 449 348 357 348H251L295 575C302 609 304 615 338 615H426C502 615 517 604 526 581C534 560 536 524 537 492L565 494C574 554 583 631 584 650Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="607" vert-adv-y="607"/></g></svg> (734C>A) Gene Polymorphisms

<table>Mean plasma concentration-time profiles of caffeine and paraxanthine (17X) in 6 <svg height="16.512501" id="M65" style="vertical-align:-0.17555pt" version="1.1" viewbox="0 0 118.675 16.512501" width="118.675" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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</svg> GA/CA genotype subjects after a single oral dose of 100 mg caffeine before (hollow) and after (solid) 14-day quercetin treatment.</table>

BioMed Research International

fig2

Figure 2

Figure 2: Quercetin Significantly Inhibits the Metabolism of Caffeine, a Substrate of Cytochrome P450 1A2 Unrelated to <svg  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2812004pt" id="M1" height="16.6263pt" version="1.1" viewBox="-0.0657574 -16.3451 89.8386 16.6263" width="89.8386pt"><g transform="matrix(.018,0,0,-0.018,0,0)"><path id="g113-68" d="M645 631C614 643 545 666 457 666C215 666 23 519 23 283C23 90 158 -16 337 -16C412 -16 489 2 522 10C543 39 590 127 606 167L580 181C519 89 459 18 348 18C201 18 122 136 122 287C122 464 244 632 435 632C544 632 602 595 608 472L639 475C643 526 645 581 645 631Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="668" vert-adv-y="668"/></g><g transform="matrix(.018,0,0,-0.018,11.946,0)"><path id="g113-90" d="M640 650H413L406 622L438 617C475 611 483 605 463 571C422 503 346 400 296 333C264 403 215 529 199 575C189 604 191 614 228 618L262 622L271 650H30L23 622C90 615 97 609 119 553L212 321C222 295 223 285 218 259L193 127C176 39 167 33 82 28L76 0H350L356 28C266 36 257 40 275 127L303 266C308 290 314 302 328 322C396 418 454 493 498 546C551 610 565 616 631 622L640 650Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="652" vert-adv-y="652"/></g><g transform="matrix(.018,0,0,-0.018,22.357,0)"><path id="g113-81" d="M600 480C600 590 528 650 384 650H143L137 622C222 614 225 607 210 531L130 127C113 41 106 36 23 28L17 0H294L300 28C204 36 195 42 212 127L243 284L314 263C327 263 339 263 352 264C465 271 600 337 600 480ZM508 481C508 351 402 304 329 304C289 304 265 311 250 317L295 559C302 594 310 606 323 611C335 616 350 619 367 619C455 619 508 573 508 481Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="617" vert-adv-y="617"/></g><g transform="matrix(.018,0,0,-0.018,33.399,0)"><path id="g113-50" d="M384 0V27C293 34 287 42 287 114V635C232 613 172 594 109 583V559L157 557C201 555 205 550 205 499V114C205 42 199 34 109 27V0H384Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="480" vert-adv-y="480"/></g><g transform="matrix(.018,0,0,-0.018,41.983,0)"><path id="g113-66" d="M686 28C612 35 607 44 591 112C563 234 541 360 519 489L489 666L457 658L147 121C100 40 89 36 24 28L17 0H240L250 28C168 34 159 41 190 101L262 237H482C495 180 503 137 510 91C517 47 514 35 441 28L433 0H677L686 28ZM475 280H285L429 541H431L475 280Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="703" vert-adv-y="703"/></g><g transform="matrix(.018,0,0,-0.018,54.549,0)"><path id="g113-51" d="M412 140C382 77 369 73 315 73H129L270 222C362 320 402 379 402 466C402 571 322 635 234 635C177 635 130 609 99 576L42 495L64 475C90 514 133 568 201 568C274 568 318 519 318 435C318 349 255 267 193 193C144 135 87 78 32 23V0H405C417 45 427 89 440 131L412 140Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="480" vert-adv-y="480"/></g><g transform="matrix(.013,0,0,-0.013,63.133,-7.899)"><path id="g190-43" d="M364 493V518L231 520L258 659L234 665L176 533L55 613L40 592L144 490L42 396L56 374L178 451L248 321L271 330L232 468L364 493Z"/><glyph.data ascent="989" descent="-360" horiz-adv-x="404" vert-adv-y="404"/></g><g transform="matrix(.018,0,0,-0.018,68.867,0)"><use xlink:href="#g113-50"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="480" vert-adv-y="480"/></g><g transform="matrix(.018,0,0,-0.018,77.451,0)"><use xlink:href="#g113-68"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="668" vert-adv-y="668"/></g></svg>  (−2964G>A) and <svg  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-5.2715pt" id="M2" height="21.6166pt" version="1.1" viewBox="-0.0657574 -16.3451 25.3778 21.6166" width="25.3778pt"><g transform="matrix(.013,0,0,-0.013,0,-7.899)"><use xlink:href="#g190-43"/><glyph.data ascent="989" descent="-360" horiz-adv-x="404" vert-adv-y="404"/></g><g transform="matrix(.018,0,0,-0.018,5.734,0)"><use xlink:href="#g113-50"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="480" vert-adv-y="480"/></g><g transform="matrix(.018,0,0,-0.018,14.318,0)"><path id="g113-71" d="M584 650H137L131 622C214 614 217 612 200 521L125 127C109 41 101 35 23 28L17 0H288L294 28C201 35 193 42 209 128L242 309H348C440 309 442 300 443 226H471L510 422H482C452 354 449 348 357 348H251L295 575C302 609 304 615 338 615H426C502 615 517 604 526 581C534 560 536 524 537 492L565 494C574 554 583 631 584 650Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="607" vert-adv-y="607"/></g></svg> (734C>A) Gene Polymorphisms 

Figure 2 | Quercetin Significantly Inhibits the Metabolism of Caffeine, a Substrate of Cytochrome P450 1A2 Unrelated to   (−2964G>A) and  (734C>A) Gene Polymorphisms 