phlobaphene

Natural phlobaphenes are the common bark, pericarp, cob glume and seed coat (testa) pigments. They have not been found in flowers, unless the brown and black pigments in the involucrum of certain compositae are found to be of the phlobaphene type.{{Cite journal|doi=10.1146/annurev.pp.06.060155.001421|title=Colour Development in Flowers|year=1955|last1=Paech|first1=K|journal=Annual Review of Plant Physiology|volume=6|pages=273–298}}

In bark, phlobaphenes accumulate in the phellem layer of cork cambium, part of the suberin mixture.{{cite book|url=https://books.google.com/books?id=Va3ED4zwXGIC&q=Handbook%20of%20Nuts%3A%20Herbal%20Reference%20Library%20Par%20James%20A.%20Duke&pg=PP1 |title=Handbook of Nuts: Herbal Reference Library|isbn=978-0-8493-3637-9|last1=Duke|first1=James A|date=2000-11-10|publisher=CRC Press }} Par James A. Duke

File:Cinchona officinalis 001.JPG bark]]

Many cinchona barks contain a particular tannin, cinchotannic acid, which by oxidation rapidly yields a dark-coloured phlobaphene[http://chestofbooks.com/health/materia-medica-drugs/Textbook-Materia-Medica/Cinchona-Bark-Cortex-Cinchonae-Part-3.html Cinchona Bark (Cortex Cinchonae). Part 3] called red cinchonic,[http://chestofbooks.com/health/materia-medica-drugs/The-Essentials-Therapeutics/Cinchonaceae-Part-2.html Cinchonaceae on chestofbooks.com] cinchono-fulvic acid or cinchona red.[http://www.1902encyclopedia.com/Q/QUI/quinine.html Quinine on www.1902encyclopedia.com]

They are common in redwoods barks like Sequoia sempervirens{{Cite journal|doi=10.1021/ie50418a008|pages= 907–910|title=Chemical Nature of Redwood Tannin and Phlobaphene|year=1944|last1=Buchanan|first1=M. A.|last2=Lewis|first2=H. F.|last3=Kurth|first3=E. F.|journal=Industrial & Engineering Chemistry|volume=36|issue=10}} or in oak barks where the chief constituent, quercitannic acid, a molecule also present in quercitron, is an unstable substance, having a tendency to give off water to form anhydrides (phlobaphenes), one of which is called oak-red (C₂₈H₂₂O₁₁).

Cuscuta europaea L., the European dodder, is reported to contain 30,000 ppm in the root.Hager's Handbuch der Pharmazeutischen Praxis, List, P.H. and Horhammer, L., Vols. 2–6, Springer-Verlag, Berlin, 1969–1979

File:Potentilla erecta - Köhler–s Medizinal-Pflanzen-248.jpg

Phlobaphenes can be extracted from the root of the common tormentil (Potentilla erecta) as tormentil red.

File:Koeh-190.jpg

Phlobaphens can be found in the kola nut (where they are called kola red),{{Cite web | url=http://www.healthy.net/scr/mmedica.aspx?MTId=1&Id=236 | title=Herbal Medicine Materia Medica: Kola}} chocolate liquor (called cocoa red){{cite book

|url=https://archive.org/details/foodstheircompo00blytgoog

|title=Foods: Their composition and analysis

|first1=Alexander Wynter

|last1=Blyth

|first2=Meredith

|last2=Wynter Blyth

|publisher=C. Griffin & Co., Ltd.

|year=1903

|page=[https://archive.org/details/foodstheircompo00blytgoog/page/n254 236]

}} or in the red skins or testa of the peanut.{{Cite journal|doi=10.1007/BF02649320|title=The tannin and related pigments in the red skins (Testa) of peanut kernels|year=1950|last1=Stansbury|first1=Mack F.|last2=Field|first2=Elsie T.|last3=Guthrie|first3=John D.|journal=Journal of the American Oil Chemists' Society|volume=27|issue=8|pages=317|s2cid=95107923}} They are also reported in the fruits of the genus Crataegus (Fructus Crataegi)or can be extracted from hop flowers.[http://chestofbooks.com/crafts/scientific-american/sup1/The-Principles-Of-Hop-Analysis.html The Principles Of Hop-Analysis, Cech G. O.]

File:Corymbia calophylla kino.jpg (marri)]]

The chief constituent of kino is kinotannic acid, of which it contains 70 to 80 per cent. It also contains kino red, a phlobaphene produced from kinotannic acid by oxidation.[http://www.henriettesherbal.com/eclectic/bpc1911/pterocarpus.html Kino on www.henriettesherbal.com]

Phlobaphenes are not present in the model plant Arabidopsis thaliana but can be studied as the pigment responsible for the red color in some monocot cereals, including wheat,{{Cite journal|doi=10.1007/s10681-005-7854-4|title=Red grain colour gene (R) of wheat is a Myb-type transcription factor|year=2005|last1=Himi|first1=Eiko|last2=Noda|first2=Kazuhiko|journal=Euphytica|volume=143|issue=3|pages=239|s2cid=26883288}} maize{{Cite web |url=https://eglab.osu.edu/projects/phlobaphene |title=Phlobaphene biosynthesis in maize |access-date=2016-11-04 |archive-date=2017-08-01 |archive-url=https://web.archive.org/web/20170801160159/https://eglab.osu.edu/projects/phlobaphene |url-status=dead }} or sorghum.[http://trophort.com/research/p/102/phlobaphene.php Phlobaphene on trophort.com] {{webarchive|url=https://web.archive.org/web/20120301094216/http://www.trophort.com/research/p/102/phlobaphene.php |date=2012-03-01 }}

In maize, phlobaphenes are synthesized in the flavonoids synthetic pathway{{Cite journal|pmid=12096095|year=2002|last1=Himi|first1=E|last2=Mares|first2=DJ|last3=Yanagisawa|first3=A|last4=Noda|first4=K|title=Effect of grain colour gene (R) on grain dormancy and sensitivity of the embryo to abscisic acid (ABA) in wheat|volume=53|issue=374|pages=1569–1574|journal=Journal of Experimental Botany|doi=10.1093/jxb/erf005|doi-access=free}} from polymerisation of flavan-4-ols{{Cite journal|doi=10.1104/pp.126.2.485|title=Flavonoid Biosynthesis. A Colorful Model for Genetics, Biochemistry, Cell Biology, and Biotechnology|year=2001|last1=Winkel-Shirley|first1=B.|journal=Plant Physiology|volume=126|issue=2|pages=485–493|pmid=11402179|pmc=1540115}} by the expression of maize pericarp color1 (p1) gene{{Cite journal|pmid=1266355|year=1976|last1=Braess|first1=CH|title=Is Igls worth a journey? Report on the 19th International Congress on General Medicine of the SIMG in Igls/Innsbruck, September 22–27, 1975|volume=52|issue=8|pages=432–433|journal=Zeitschrift für Allgemeinmedizin|last2=Cocciolone|first2=SM|last3=Bushman|first3=S|last4=Sangar|first4=V|last5=McMullen|first5=MD|last6=Peterson|first6=T}} which encodes an R2R3 myb-like transcriptional activator[http://www.intl-pag.org/16/abstracts/PAG16_P05d_343.html Structural And Transcriptional Analysis Of The Complex P1-wr Cluster In Maize. Wolfgang Goettel, Joachim Messing. Plant & Animal Genomes XVI Conference] {{webarchive|url=https://web.archive.org/web/20120218100748/http://www.intl-pag.org/16/abstracts/PAG16_P05d_343.html |date=2012-02-18 }} of the A1 gene encoding for the dihydroflavonol 4-reductase (reducing dihydroflavonols into flavan-4-ols){{Cite journal|doi=10.1104/pp.127.1.46|title=Functional Conservation of Plant Secondary Metabolic Enzymes Revealed by Complementation of Arabidopsis Flavonoid Mutants with Maize Genes|year=2001|last1=Dong|first1=X.|journal=Plant Physiology|volume=127|pages=46–57|pmid=11553733|last2=Braun|first2=EL|last3=Grotewold|first3=E|issue=1|pmc=117961}} while another gene (Suppressor of Pericarp Pigmentation 1 or SPP1) acts as a suppressor.{{Cite journal|title=Suppressor of Pericarp Pigmentation 1 (SPP1), a novel gene involved in phlobaphene accumulation in maize (Zea mays L.) pericarps|author1=Lee E.A |author2=Harper V |journal= Maydica|year=2002| volume =47| issue= 1| pages =51–58|id= {{INIST|13772300}} }} The p1 gene encodes an Myb-homologous transcriptional activator of genes required for biosynthesis of red phlobaphene pigments, while the P1-wr allele specifies colorless kernel pericarp and red cobs, and unstable factor for orange1 (Ufo1) modifies P1-wr expression to confer pigmentation in kernel pericarp, as well as vegetative tissues, which normally do not accumulate significant amounts of phlobaphene pigments. The maize P gene encodes a Myb homolog that recognizes the sequence CCT/AACC, in sharp contrast with the C/TAACGG bound by vertebrate Myb proteins.{{Cite journal|doi=10.1016/0092-8674(94)90117-1|title=The myb-homologous P gene controls phlobaphene pigmentation in maize floral organs by directly activating a flavonoid biosynthetic gene subset|year=1994|last1=Grotewold|first1=Erich|last2=Drummond|first2=Bruce J.|last3=Bowen|first3=Ben|last4=Peterson|first4=Thomas|journal=Cell|volume=76|issue=3|pages=543–553|pmid=8313474|s2cid=42197232}}

In the sorghum, the corresponding yellow seed 1 gene (y1){{cite journal|doi=10.1016/j.plantsci.2005.05.007|id= {{INIST|16983977}}|title=Characterization of a deletion allele of a sorghum Myb gene yellow seed1 showing loss of 3-deoxyflavonoids|year=2005|last1=Boddu|first1=Jayanand|last2=Svabek|first2=Catherine|last3=Ibraheem|first3=Farag|last4=Jones|first4=A. Daniel|last5=Chopra|first5=Surinder|journal=Plant Science|volume=169|issue=3|pages=542 }} also encodes a R2R3 type of Myb domain protein that regulates the expression of chalcone synthase, chalcone isomerase and dihydroflavonol reductase genes required for the biosynthesis of 3-deoxyflavonoids.{{Cite journal|doi=10.1007/s11103-005-3568-1|title=Comparative Structural and Functional Characterization of Sorghum and Maize Duplications Containing Orthologous Myb Transcription Regulators of 3-Deoxyflavonoid Biosynthesis|year=2006|last1=Boddu|first1=Jayanand|last2=Jiang|first2=Cizhong|last3=Sangar|first3=Vineet|last4=Olson|first4=Terry|last5=Peterson|first5=Thomas|last6=Chopra|first6=Surinder|journal=Plant Molecular Biology|volume=60|issue=2|pages=185–199|pmid=16429259|s2cid=23841582}}

It is a dark-colored resin-like substance made of water-insoluble, alcohol-soluble polymers{{Better source needed|reason=The current source is insufficiently reliable (WP:NOTRS).|date=April 2025}}.[http://ecsoc2.hcc.ru/ecsoc-2/dp083/dp083.htm Dihydroquercetin dimers by oxidative coupling reactions. Gonzalez-Laredo, Ruben F., Malan, Johannes C.S., Chen, Jie, Todd, Jim, Karchesy, Joseph J. 2nd International Electronic Conference on Synthetic Organic Chemistry (ECSOC-2), September 1–30, 1998]

Phlobaphens can be formed under action of acids or heating of condensed tannins or of the fraction of tannins called phlobatannins. Water containing soda can be used for the conversion of hop tannins into phlobaphens.Dingler's Polytech. Journ., C. Etti, 1878, p. 354. When heated with hydrochloric acid, tannins in cocoa solids yield a glucose and a phlobaphene.Warden C. J. H., Pharm. Jour., [3], xviii. 985

Ordinary or warm soluble quebracho (also known as insoluble quebracho) is the natural extract obtained directly from the quebracho wood. This type of extract is rich in condensed tannins of natural high molecular weight (phlobaphenes), which are not easily soluble. Its use is therefore limited to small additions during sole leather tannage carried out in hot liquors (temperature above 35 °C) to improve the yield and the water-proofness of the leather. The cold soluble extracts are obtained by subjecting the ordinary extract to a sulfiting process which transforms the phlobaphenes into completely soluble tannins. The cold soluble quebracho extracts are the most universally known and used types. The main properties of these extracts are: a very rapid penetration, a high tannin content and a relatively low percentage of non-tannins. The rather low acid and medium salt content characterise them as mild tanning extracts (low astringency).

Phlobaphenes formation (tannins condensation and precipitation) can be minimized in using strong nucleophiles, such as phloroglucinol, m-phenylenediamine and urea, during pine tannins extraction.{{Cite journal|doi=10.1007/BF02663290|title=Increased pine tannins extraction and wood adhesives development by phlobaphenes minimization|year=1992|last1=Sealy-Fisher|first1=V. J.|last2=Pizzi|first2=A.|journal=Holz Als Roh- und Werkstoff|volume=50|issue=5|pages=212|s2cid=6585979}}

The use of synthetic tannin neradol D can help solubilize phlobaphene in tanning solutions.{{Cite book|url=https://books.google.com/books?id=JlAScMCWpFIC&q=phlobaphenes&pg=PA112|title= Synthetic Tannins|author= Georg Grasser|isbn=978-1-4067-7301-9|date=March 2007|publisher= Read Books}}

{{reflist}}

• [http://www.liberherbarum.com/In1620.HTM Phlobaphene on www.liberherbarum.com]

{{Condensed tannin}}

Category:Tannins

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