Polyphenols - Science topic

I have used the QIAGEN DNeasy kit to obtain fecal prey DNA from an herbivore and a few of the samples have higher polyphenol levels, which have given a yellowish tint to the final eluted DNA solution.

Should I go ahead with Geneclean (suitable for 200–20 kb) DNA purification from solutions or the traditional ethanol and sodium acetate precipitation to remove the PCR inhibitors in the form of polyphenols and other plant secondary metbolites?

We have synthesized different metal oxide nanoparticles (ZnO,Fe2O3) using aqueous plant extracts as a solvent/reducing agent. XPS and FTIR have revealed the presence of phytochemicals on the metal oxide nanoparticles. Can anyone suggest an analytical technique to to identify the phytochemical incorporated in the metal oxide during the synthesis? Our primary inference is that it may be some of the polyphenols present in the plant extract. Can ESIMS be used or are there any other techniques?

Dear Researchers

I am an Algerian PhD student in biology, and I study some biological activities and secondary metabolites of some fungi. I desperately seek a foreign laboratory that provides LC-MS/MS services for PhD students and researchers.

Do you have reliable laboratory addresses that can do LC-MS/MS analysis of lichenic polyphenols?

I appreciate all your suggestions and help.

I quantified the total flavonoid content (TFC) of betel leaf extract by using colorimetric AlCl3 method. I used the chemicals of AlCl3, NaNO2, and NaOH on the ethanolic extract and rutin as a standard. After quantification, I determine that the TFC of the extract is equivalent to more than 1,000 mg rutin/g dry extract. This value is remarkably high compared with many previous works but I haven't got any reasonable explanation for this. Have anyone encountered the same case as it? As I know, the phytochemical composition of the betel leaf extract includes flavonoids, polyphenols, tannins, hydroxychavicol, chavibetol etc. These compounds have two neighboring phenolic groups that can interact with Al to generate the complexes. May this the reason lead to the extremely high TFC in my case?

I have initial grape and blackcurrant powders, that have gone through polyphenol extraction process with 30% ethanol and 0.1% acetic acid. I have conducted a Folin assay on them to get the polyphenol content. At the next stage, I encapsulated the extracts with gum Arabic and spray-dried them. The spray-dried powders have gone through the same extraction condition with the same percentage of ethanol and acetic acid. The supernatants were collected for a Folin assay to get the polyphenol content. To calculate the encapsulation efficiency, I have divided the values of TPC in the powders by the TPC in the initial extracts and multiplied by 100. Strangely, I have gained results of more than 100, such as 200%, 300%, etc. Moreover, I have prepared dilutions of my samples to get absorbance within the standard curves. Could you please guide me on what is wrong with my measurements? Or if you could kindly share some hints in this regard. Thank you.

I have apple pomace that contains the flesh, stems, seeds and skin. I want to make an extraction of all the soluble polyphenols in the apple pomace. What is the simplest way to do this?

Also, is there an additional step to isolate the bound-polyphenols too?

Hello. We have a sample with an unknown concentration of polyphenols. We're diluting the sample in order to perform the Folin Ciocalteau method.

0.2 grams sample / 4 mL 70% methanol and 30% water = initial

200 microliters initial /800 microliters solvent = next dilution

100 microliters initial /900 microliters solvent = final dilution

We performed this several times. However, the final concentration calculated from our standard curve for each dilution was different. Additionally, all the replicates had a general (but not mathematic) trend of increasing concentrations with increasing dilutions. I was wondering where we could be going wrong in our approach and what could be causing this (assuming it's an error in our calculations).

Thanks.

How do I calculate the total polyphenol content in mg GAE/g. from the extract?

Following is my data:

Sample extract(stock): 0.01 gram in 1 ml

Equation: y= 0.0078x - 0.0679, R2 = 0.9969

Absorbance: Sample was serially diluted-

1000(µg/ml)=0.598

500(µg/ml)= 0.296

250(µg/ml)=0.127

125(µg/ml)=0.063

62.5(µg/ml)= 0.026

What is the dilution factor here? How can I calculate x in the form of mg GAE/g?

Can anyone please help me?

I extracted protein from a roasted food sample using alkaline extraction followed by acid precipitation. Polyphenols were always coextracted since they were covalently bound with proteins during roasting and the formation of covalent bonds were irreversible. How can I know how abundant covalently-bound and noncovalently-bound polyphenols are in my protein extracts? I would greatly appreciate it if you could provide any suggestion or guidance.

I am trying to purify protein extracts but polyphenols are covalently bound with proteins during roasting. Is there any method to remove covalently-bound polyphenols and purify proteins? Thank you!

I recently performed the glycidylation of some polyphenols. And I just read a paper (Doi: ). I'm really confused about the chemical structure of the side-product with the benzodioxane structure. I've drawn it in the attached file. Could anyone tell me why?

I'm trying to do a DPPH antioxidant test but when I mixed all the reagents with my polyphenol extract, some of the samples turned cloudy. Why does it happen and how can I prevent it? I am working on Dong Quai ginseng with different drying conditions.

Curcumin is one of the active ingredients in turmeric that is also responsible for its health benefits. It is a type of polyphenol, also a type of antioxidant that helps protect cells from any kind of damage. Curcumin is also thought to be one of the most powerful antioxidants and anti-inflammatory compounds available.

I have some columns for my Thermo Scientific GC-MS:

1) DB-WAX

2) DB-1

c) DB-17HT

d) VF-1MS

e) TR-FAME

f) TG-5MS

g) TG-WAXMS A

In my opinion, for polyphenols as flavonoid (and their glicosides) and phenolic acids (present in vegetable, grains, food analysis), I would prefere DB-1, VF-1MS and TG-5MS.

Your opinion will be valuable for me...a lot!

I am using TG-5MS. but I expected better results than the ones I am having...

Is it necessary to quantify each standard with its specific compound, or can I use a single standard to quantify two different compounds with the same chemical structure, for example?

I am using Agilent 7000 series GC-MS/MS for the analysis of DTC pesticides such as Mancozeb and Zineb but the LOQ cannot be lowered up to 10 mg/Kg as there is matrix interference from the tea polyphenols. Please suggest some methods to do the same.

I am interested in ELSD, an HPLC detector.

Is there anyone who is currently using or has used this detector?

I would appreciate it if you could share information on the problems, concerns, and advantages of using it in real world situations.

It would also be appreciated if you could introduce, for example, review articles explaining the characteristics of quantitative measurements of analogous compounds without their standards.

I would like express my gratitude to everyone in this community.

I appreciate it.

Best regards,

Hi, my name is Anna.

I am working on the extraction of polyphenols and carotenoids from date seeds using NADES.

I am centrifuging the samples at 14400 rpm-20min-10ºC but when I remove the supernatant, the liquid looks cloudy.

What could I do to remove those particles that can interfere in the assays? Perform a filtration on paper?

Thanks for your help and best regards,

Anna

I am trying to analyse the polyphenolic or flavonoid content of my honey sample. Can I do it with some new method that doesn't require purchasing any standard for chemical compounds?

I have performed many chromatin extractions, but at the end of every experiment I have a large peak at 220-240nm when measuring DNA concentration with a nanodrop. I have had some very limited success by including diethyldithiocarbamic acid (DIECA) and pvp-40 in all of my solutions, but the peak remains.  I assume that it is DNA oxidation and not polysacharides because multiple ethanol washes through a cellulose column does not eliminate this peak from the spectra.  Anyone have any suggestions

The confusion is between metal nanoparticles formation and curcumin-piperine nanparticle which are natural polyphenols. After formation of curcumin-piperine nanoparticles the UV-VIS absorption graph show changes but i am unable to decide the lambda max ? because in many papers no different wavelength of curcumin and piperine nanoparticle are used only 424 and 343nm characterstic wavelengths are used. so icnt decide whether wavelength should change or not after nanoparticles fomation pls explain?

I evaluated the antioxydant of ethanolic extract by DPPH. I chose a concentration of 1000 ug/ml and then 2000 ug/ml very high concentractions but no yellow color appeared when adding DPPH. Knowing that my extract is high in polyphenols and flavonoids. Can anyone please expert on this field help me and give me an explanation on what happens?

Thank you

Does drying leaves and stems in a high humidity environment influence the bioactive molecules like flavonoids and polyphenols or no?

I am currently doing nanoparticle formulation using chitosan. The active ingredient for the formulation is polyphenol from the plant extract. So, how do I know and confirm what size of dialysis bag to use for in vitro release study. Thank you.

Why natural polyphenols (like proanthocyanidins from berries) decrease their antioxidant activity in a lipid environment? vs an aqueous environment?

I know that existing research suggests that the lipid solvent lowers polyphenol antioxidant activity. But why? It is because their favored the prooxidation of lipids?

Thanks guys.

Is there a way I can visualize curcumin in mice tissues (for example after subcutaneous administration of a curcumin formulation) employing some sort of specific stain for curcumin or polyphenol or similar? Employing autofluorescence of curcumin is hampered by tissue autofluorescence. And I think employing the usual staining methods for lipids or phenols would stain non-specific lipidic or proteinic regions of the tissue.

Hello,

Many researchers reported that to extract polyohenols you need first to remove lipids. I don't know why? Knowing that removing lipids can leads to a loss of polyphenols even if the solvent is apolar.

We measured the amount of total polyphenols in plasma, while Gallic acid was used as the standard and we have the results of absorbance. Now we need to know the calculation method or formula for have the final exact concentration. (by considering for example: dilution factor, time, ...).

Do I have to extract the polyphenols like we do with the powder, or not.

how to determine the concentration of the syrup?

Thank you.

with special reference of Nicotine waste.

Why is gallic acid for TPC and quercetin for TFC the standards used in these assays? All studies I have come across use Gallic acid equivalents and quercetin equivalents to express TPC and TFC values. Aside from a fact that gallic acid is a phenolic acid and quercetin is a flavonoid, are there any other reasons more to it?

I'm treating BV2 with vegetal compounds in order to study the effect on inflammation.

Experimentally I have found that the prepared curcumin pyrazole has more polyphenolic content compared to pure curcumin but could no explain the reason behind. Can anyone please help me with the explanation?

Hi,

I want to compile a list of crops may have the black leave/stem/husk/grain trait. I have noticed rice and barley so far, maybe wheat as well.

Any other crops or plants that can display this trait from your knowledge? How about Brachypodium, maize, sorghum, oat, Setaria italica etc?

I want to study the physical and oxidative stability of O/W emulsion stabilized by protein-polyphenol conjugates under accelerated storage conditions.

I want to avoid the temperature factor because the emulsions are not physically stable at 50°C, after two weeks an oil layer is forming on top of the emulsion.

I was then thinking about using FeSO4 or the complex FeSO4/EDTA to accelerate the oxidation however, I saw that phenolic antioxidants can act as prooxidants under certain conditions (for example, high concentration of transition metal ions) (Eghbaliferiz, S, 2016).

I was wondering if by using FeSO4 and the conjugates that contain polyphenol, the lipid oxidation would increase in comparison to the control (protein alone). Does anyone have any experience with this situation?

Thank you very much for your help!

I want to optimize the parameters of ultrasound-assisted extraction of phytochemicals for my work. I have used amplitudes of 20%, 60% and 100%. I want to check if the Total Polyphenol Content obtained for 100% amplitude is significantly higher than 60% or 20%. Which statistical test should I perform for this purpose? Kindly help, and thanks in advance!

Hello, please I need help with a statistical analysis. I don't know what statistical test to use. The study I carried out is as follows: Quantify polyphenols, flavonoids and anthocyanins in addition to antioxidant activity for 2 different concentrations of a fruit. I'm not sure what statistical analysis to perform

Hi everyone.

I m actually trying to install a method {COI/T.20/Doc. No 29/Rev.1 2017} for the determination of olive oil polyphenols.

I'm using an HPLC and the result are ok. I mean that the chromatogram is quite well. I can identify every pic and the FFR factor after 7 months is the same.

The problem is that we quantify 100 or 200ppm less than other laboratories and I cannot find the reason.

The preparation of the sample is the same, the only thing that change is the detector of the HPLC. I think is that the problem but I don't know if there is a way to be sure.

How can you say leaves are fresh in terms of its moisture content? Is a 100% moisture content possible? Does it mean that plant leaves that were harvested and subjected right away to IR moisture balance will give us a result of somewhere near 100%?

On the other hand, does "dried leaves" have specific moisture content values to be regarded as "dried" e.g. moisture content should be below a certain percent (10%).

For reference, I am studying Cymbopogon citratus leaves.

when I measured the total flavonoids and total polyphenols of my 15 day old plants (Vigna unguiculata), I found that the amount of flavonoids is greater than the amount of polyphenols, and to my knowledge flavonoids are polyphenols. so please explain

Hello researchers

Please can you tell me how can we extract alkaloids from plants? Are the extraction of alkaloids same as polyphenols?

I wanted to extract total RNA in plant fruit tissues which is abundant of polyphenol and polysaccharide in a high yield (about 100-200 ug). Traditional CTAB and TRIzol method were not suitable which performed low 260/230 (<1.6 sometimes even ~0.1-0.5) and low yield. I tried high concentration KCl and PVP-20000 in CTAB extractive solution and added NaCl and Na-citrate while precipitating by 2-propanol, finally after 75% EtOH wash, although 260/230 and 260/280 all come to about 2.20, it still possessed some gel-like things combined with RNA pellet (thick while redissolving by water) and this method has really low yield (about 24 ug for every 800 mg frozen tissues).

Technically, it is not possible as flavonoids are part of polyphenols.

i am currently looking for methods to detect a polyphenol compound in packaged grape juice with the highest sensitivity. i am however worried that the additives in juice may interfere with my detection assay. it may help to know how they react with the polyphenols so that i can perform that assay without any flaws. can you please state the ways in which these food additives might interfere with my detection assays?

Hello,

I'm attempting an LC-MS analysis for a plant methanolic extract for the sake of polyphenol and terpenes quantification. I'm following a protocol used by Nivea M. et al., (2019) in which they used Ribitol as an internal standard.

I was wondering if I can substitute Ribitol with another standard and if I can then what are the possible choices I can use?

Thank you

I am currently doing a research on targeted polyphenol profiling of one plant from different locations. Together with this i am going to test their antioxidant activities as well. I am confused if I should apply the biological replicates here because of the recommendations from the metabolomics standards initiative. Is this applicable to my study? I am concerned with the ampunt of samples because it might take too much time and resources since i have 5 locations and i will be testing both fresh,oven dried and air dried samples so a total of 3 samples per location. If i do this is 3 biological replicates, it’ll be 9 samples per location.

Anyways regardless, I will still be analysing each samples in 3 trials.

After extracting my industrial fruit waste (dried 50g in 100ml distilled water) and measuring its TPC. I went straight into assessing its antibacterial activity. My extract is in liquid form (no rotary evaporation/lyophilization/spray drying). After quick well diffusion tests, I attempted determination of MIC (microbroth dilution method) with Mueller-Hinton broth in U-bottom 96-well microplates.

I then came to realize that I don't exactly know the concentration of my extract. Thus, my question is could I use the mg GAE/ml as the concentration? or is my concentration 50g/100ml i.e. 500mg/ml? or should I dry in the oven (100-120oC) overnight 1ml of my extract and calculate the weight difference per 1ml as my concentration?

Thanks

Edit for anyone interested: After several adjustments, the antibacterial assessment will follow with considering the waste in its "crude" extract state and assessing its MBC/MIC ratio with the literature.

Hi guys,

I need some advice over here.

Im trying to do a liposomal encapsulation via microfluidics of a natural extract diluted in etanol, it is rich in polyphenols. Im using Oleic Acid + Cholesterol + tween 20 for the lipid layer. During the process in getting a precipitate and very few microcapsules.

is normal or less sugar is better to reduce acrylamide content in potato chips? and why??

I did a qualitative screening of 2 plants extracts. And both plants showed a negative result for polyphenol but positive for flavonoids. I know flavonoids are a class of polyphenols so I'm a bit confused on how to interpret that. And take into account that the quantitative screening for TPC (total phenolic content) shows results.

Hi RNA experts,

I am trying to extract RNA from my blueberry fruit samples. They have been stored in -20 C for one or two months and then they were moved to -80 C. I used the Qiagen RNeasy Plant Mini Kit for extraction. The same lab/method/environment used for RNA extraction in other plant materials was used but I failed to extract RNA for these blueberry samples.

From QC, I got:

1. "too low" or close to 10.0 results (very low) from Qubit BR assays.

2. no visible bands from agarose gel electrophoresis.

3. 0.7-1.9 260/280 ratios from nanodrop (extensive variation).

What do you think the problem could be?

Could the high water content of the fruit be causing poor extraction?

Could storage temperature be the problem? Is it okay to store the samples before RNA extraction at -20 C?

Could the polyphenolics and polysaccharides be hindering extraction?

Dear colleagues, In recent years a lot of research groups started to use prediction tools such as metabolomic circuit, QSAR, and molecular docking as additional tools to gain time and reagents. Some articles described the polyphenol and flavonoid contents without determinating the chemical composition of plant extracts, I would like to know if there is a tool that can be used to predict antioxidant activity from the TPC and TFC, if yes how it can be done and is it a reliable tool ?

best regards.

We are looking for high purity brown algae polyphenol (phlorotannins) samples. I am currently based in China. If you have any information about where could I purchase samples. Please let me know. Thanks.

We observed the low antioxydant activity of our extract whereas the level of total flavonoids and total polyphenols are high.

I ran my methanolic extracts (flavonoids compounds) over silica gel, then no separation took place due to the complexity of the mixture. I collected all the test tubes fraction together and I removed the solvent. Consequently, the first color was white turned yellow! While, I didn't separate any fraction and all the fractions were concentrated together!

How can we explain the change of colors, whereas we didn't make any isolation?

As we know Like dissolves Like; polar analytes are dissolved in polar solvents.

I noticed in an article that they use the soxhlet apparatus with a temperature in the range of 70-80° to recover methoxyflavoinds (polar class of compounds)!

I'm just questioning if the temperature might plays the role to extract polar compounds even with apolar solvent?

Are there other methods besides the Folin-Ciocalteu method and Prussian blue?

I am a PhD student from Nigeria and am working on nutritional interventions against heavy metal toxicities. I enriched polyphenols from some plant extracts and i wish to characterize the polyphenol contents of these extracts using LC/MS or other appropriate technologies. Please can anyone refer any laboratory that accepts international samples for such analysis? I am also open to collaborate with scientist that are expert in doing such types of analysis. Thanks

I cannot find sources which gives a thorough explanation of PCA and how to assign the principal components 1 & 2 including their computations. Say for example, my study will explore polyphenol profiles of a certain plant from different geographical area and I will test their antioxidant activity too and analyze them using biochemometric approach. Which variables should be included in principal components? I will also integrate data from this PCA to construct my OPLS DA.

Does anyone know the method for the determination of polyphenol content in addition to the Folin-Ciocalteu method and Prussian blue?

I am preparing phytosome which is a drug delivery system using phosphotidycholine dissolved in DCM and polyphenols dissolved in water then homogenize....The results I get for zeta potential is negative yet am trying to target positive zeta potential but the size I am getting is below 250nm...When I introduce chitosan in the preparation I am getting A zeta potential above +30 mV but the size is above 1000nm. Is there anyone who can help me know where i am going long ...or is there anyone who can help me know an alternative i can use beside chitosan?

What is the best method for Polyphenol oxidase in grapes. I had already try following method:

Hi, I am checking the antioxidant activity of polyphenols using the DPPH reagent. I'm taking a 0.1mM reagent. I tried two 3 things. I'm using ethanol as a solvent for my extract.

1. I made DPPH SOLUTION USING ethanol as my extracting solvent was ethanol and checked the absorbance but my standard values are coming negative while the test sample is giving +ve.

2. I also tried methanol. Made DPPH solution using methanol. here for control, I took DPPH standard solution + ethanol (s my extracting solvent was ethanol ) and test samples as meth DPPH soln with the extract. still, the absorbance values are either less or -ve.

I have tried both methods on three different instruments. Please suggest something to do?

thanks in advance!

I am trying to make nanoparticles using tannic acid and I am using Triton X-100 as the surfactant (not for stabilizing nanoparticles), which is added to tannic acid prior to the synthesis reaction. Can Triton X-100 react with tannic acid or change its structure or vice versa?

I extracted DNA from some kombucha products with a manual protocol, with one final step using phenol, for 16S and ITS sequencing.

However, there is a problem for the majority of my samples in PCR step. Apparently, there is/are some inhibitors in my samples that impede PCR. My samples pH is around 3 and they contain polyphenols.

Did anyone have any similar experience or any suggestion?

I need to determine a polyphenol profile per HPLC from yacon flour but I did not find a suitable protocol as there are too many of them. Can somebody help me?

Thanks!

Romina.

How is yeast being used in encapsulation of polyphenols? Plasmolysed or intact cells?

We are trying to estimate curcumin content in Turmeric genotypes. Rhizomes are cut in pieces and oven dried at 60 o C. Certain genotypes retained the original colour on cut surfaces and others changed to brown to dark brown on cut surfaces. What is the reason? Does polyphenol play a role ? What about other factors? We are sure that it is not due to excessive heat, as we have seen this even under lower temperatures.

Flavonoids are a group of plant secondary metabolites thought to offer health assistances through cell signaling pathways and antioxidant effects. These molecules are found in a variety of fruits, barks and vegetables. Flavonoids are polyphenolic molecules containing 15 carbon atoms and are soluble in water. How I can i isolate and separate polar flavonoids from methanolic extract easily.

What is the reason explaining that the higher percentage contents of total polyphenols and total flavonoids significantly in dried mint leaves compared to the fresh ones?

Why does drying increase the biological activities (antioxidant and anti-inflammation) of total polyphenols and total flavonoids in plant leaf extract?

Sample: plant seeds, and ethanolic extraction assisted by ultrasonic used for our samples. Both identifying and quantifying are being targeted.

We have BSTFA but I don't know the protocol of these process, and it's possible to use only BSTFA or I should mix derivative reagents. I need to know all the conditions of the process and if any other chemicals or reagents needed.

thanks in advance

In adding DHA to a health supplement, I want to know which polyphenols are best to protect against oxidation in vivo. Have you found commercially available sources and if so, can you please share this information with me? We are looking at humans and companion animals. Thank you for all you do:)

Bob Rager

Is there any way to construct a full set of database of natural polyphenolic compounds for molecular docking. Preparing the ligands one by one is time consuming? Can anyone share a easy way to do so?

I have an animal RNA extraction kit (silica column-based kit), how to adapt it for plant use? Knowing that the kits for plants normally contain two types of columns (one for preliminary filtration and the silica column) while kits for animals contain only one type of column (silica column). Other than centrifugation, how will I be able to remove debris and polyphenols?

So I understand that essential oils are formed by steam distillation, and contain volatile, usually aromatic, compounds.

Extracts are formed by immersion of plant matter in a solvent, and are usually reported to contain compounds such as polyphenols, anthraquinones, flavonoids and the like.

Practically every report I have read does not mention whether obtained extracts contain the volatile compounds found in essential oils though. Will there be volatile essential oil compounds in extracts, or can they ONLY be taken out of plant matter by steam distillation?

I'm exploring the world of emulsions, but I'm not sure if it is the correct way to solve my problem.

After searching among literature for months, I am not still able to choose a microalga strain for my PhD project. The idea is to extract as many as possible valuable compounds (such as pigments, PUFAs, polyphenols, phytosterols, vitamins) from the same microalgal biomass.

To do this, I need a strain that is being already studied and optimal conditions growth for bioproducts target are known. Also, I am not sure that selecting strains already on the market (maybe lipids or biofuels market) could be a good idea.

Which strain do you suggest?

I've found a promising strain (Stichococcus sp. KMMCC 365 but it's impossible to find to buy)