Polyphenols secretion is due to tissue type and nature only not from the effect of Medium but it should be controlled by adding a pinch of Charcoal to the culture medium

Dear Sagarika Das

Several factors affecting callus culture produce polyphenols, such pH , light, temperature,

Pls. find the attached files, may answer your questions, good luck

http://world-food.net/download/journals/2016-issue_1/2016-issue_1-agriculture/a1.pdf

http://nopr.niscair.res.in/bitstream/123456789/5366/1/IJEB%2045(12)%201063-1067.pdf

http://link.springer.com/article/10.1023/A:1013704116860

http://www.sciencedirect.com/science/article/pii/003194229280267I

http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0304-35842008000200001

http://link.springer.com/article/10.1023/A:1006119015972

http://onlinelibrary.wiley.com/doi/10.1002/food.200390045/abstract

http://www.sciencedirect.com/science/article/pii/S0734975008000803

http://www.academicjournals.org/article/article1380807978_Masoumian%20et%20al.pdf

http://bi.tbzmed.ac.ir/Portals/0/BI-2011-1-1/Khosroushahi-BI-2011-1-1.pdf

http://www.degruyter.com/dg/viewarticle.fullcontentlink:pdfeventlink/$002fj$002fnbec.2014.13.issue-2$002fnbec-2015-0006$002fnbec-2015-0006.pdf?t:ac=j$002fnbec.2014.13.issue-2$002fnbec-2015-0006$002fnbec-2015-0006.xml

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3648945/

Dr Erica Benson, Erica Benson. 2002. Plant Conservation Biotechnology CRC Press,Pp. 309. ISBN0203484193, 9780203484197

Regards

Prof. Houda Kawas

  Cultured tissues of  plants rich in  secondary metabolites  and phytochemicals may produce polyphenols.I agree with  Subba Tata that this can be controlled by addition of activated charcoal  and also  by incubation  in dark.

Regards

Indira Iyer

Polyphenols are produced in callus cultures, cell suspensions and root cultures primarily when conditions are favourable for the activation of the shikimate- chorismate pathway. These conditions depend mostly on light photoperiods and also on hormonal and types of medium ( containing macro and microelements) used . My experience is that media such as MS ( Murashig and Skoog) and Gamborg B5 are quite suitable for initiating the process of phenolic production. Addition of Shikimic acid and aminoacids such as phenylalanine increase the production of certain polyphenolic subclasses such as flavan-3-ols, phenolic acids and flavonols. However one important point to note is that initiation of callus  or cell suspension cultures from phenolic rich plants does not necessarily imply an immediate production of phenols in these cultures. Having said that I agree that activated charcoal and PVP ( Polyvinylpyrrolidone) are quite useful in absorbing phenolics in plant cell cultures.

Dear  Sagarika

I agree with the other researchers. In callus, phenols is commonly produced as consecuences of plant cell wall formation, while exudation is probabbly stress factors (callus old, hormones, gelling agent, room temperature, light, etc.). It is depending of the species. You can prove adding activated charcoal or adding cystein (50 mg/L) or citric acid (50 mg/L) to the culture medium.

Best regards,

Elisa

Thank you all for your answers. I would definitely implement the suggestions provided by you all and see what comes out of it, as Elisa said it is species dependent. Thank you once again.

Polyphenols'  Production in the medium is not due to medium composition but it is due to the nature of plant itself, where there are many plants (such as banana, sugar cane, Alhagi, ...etc.) contain phenolic compounds which when secreted in the medium after culturing, they are oxidized ( may be by light) and give brown color. Then this brown color converts to black layer on the explant surface that contacts to the medium. This black layer makes as an isolate between the medium and the explant leading to preventing the absorbance of nutrients from the medium and then the death of explant (or callus).

To prevent the oxidation of these compounds in the medium, you must add an antioxidant compound to the medium. The antioxidants such as ascrobic acid (ASA), citric acid, polyvinylpyrrolidne (PVP) and charcoal. The preferable concentrations of these antioxidants are as follows: 200 mg/l of ASA or citric acid, 200-300mg/l of PVP, and 1g/l of charcoal.

Greetings

Dear Sagarika

Secretion of Polyphenols is generally seen during explant initiation or callus culture, especially, when we are working with woody crops. Secretion level or amount of phenolics is vary from explant to explant.

Several factors are are responsible for it, eg. explant wounding or cutting, light, temperature, late sub-culturing, available of high salts in medium. 

Possible control measures:

Cultural Practices: Quick sub-culturing, Keeping cultures in dark during initial phase,

Use of chemicals viz. Ascorbic acid or Citric acid (25-100mg/L), PVP (not more than 100mg), Cystein (50-200 mg/L), DTT (50mg/L)

Others:

• Activated charcoal (200mg/L to 2g/L)
• U can also discard old callus

Hopefully, This will helps u.

Regards

Pati R

Thank you Jehan and Rajesh for your answers and suggestions.