I want to extract flavonoids from flowers. Can we dry the sample or extract freshly?
Few years ago, I made a shampoo utilizing chamomile flowers for a science fair but I did not publish that research. I became interested in chamomile (which is considered by many as a medicinal plant). Here is a paper which will be interesting for your work. Good luck.
Flavonoids could be extracted with MeOH. After HPLC investigation of the
concentrated extracts, the extract could be applied to PPC with BAW, 15% HOAc and then BEW (n-BuOH/EtOH/H2O = 4:1:2.2). Components isolated can be purified by preparative HPLC (solvent system: MeCN: H2O = 20:80 and 22:78) and Sephadex LH-20 column chromatography (solvent system: 70% MeOH). Later Qualitative HPLC analyzes of the isolated compounds could be performed using Shim-pack CLC-ODS [I.D. 6.0 x 150 mm], at a flow-rate of 1.0 ml/min, detection wavelength of 190-530 nm and eluent of MeCN/HOAc/H3PO4/H2O (6:8:3:83) for anthocyanins, and 190-360 nm and MeCN/H2O/H3PO4 (22:78:0.2) for other flavonoids. In quantitative HPLC analyses, each 0.2 g of perianth can be extracted with 2 ml of 5% HOAc for anthocyanins, and 2 ml of MeOH for other flavonoids. The extracts later can be directly analyzed with HPLC systems.
Refer:
http://facta.junis.ni.ac.rs/phat/pcat2004/pcat2004-09.pdf
http://www.agriculturejournals.cz/publicFiles/18880.pdf
One can also extract them with methanol (as mentioned above), then use an ion exchange column to isolate them from the other compounds.
See: http://www.isco.com/WebProductFiles/Applications/101/Poster_and_Paper_Reprints/Purification_of_Phenolic_Flavonoids.pdf
Organic solvents can be used, as stated above. Procyanidin isolation may involve modified methods.
The following has extensive information from the legend, Prof J B Harborne (deceased)
Phtochemical Methods
1984, pp 1-36; Methods of Plant Analysis. J. B. Harborne
.
1984
Phytochemical Methods
A Guide to Modern Techniques of Plant Analysis
Authors: J. B. Harborne
ISBN: 978-94-010-8956-2 (Print) 978-94-009-5570-7 (Online)
Thank you for your response. i need whether the flowers to be dried r fresh before going for extraction. please discuss.
Either dried or fresh will work. You may get some of the more unstable compounds using fresh flowers, in my opinion.
Dried materials are preferred as organic solvents are used. Dried plant parts are more amenable for extraction.
Please check the following link for complete details of extraction of flavonoids from Acacia flowers.
DOI 10.1007/s10457-011-9433-0
is there be a vast difference in content of flavonoid fresh and dried flower extraction suggestions please
Yes there is a difference but it is not vast as this paper shows (it is concerned about extracting flavonoids from mulberry leaves).
To better extract the flavonoids from your matrix, first you need to develop an efficient method. If you are looking for polar flavonoids, I suggest to go for microwave assisted extraction using aqueous ethanol as solvent.
The extract can further be purified suing preparatory HPLC to isolate compound of interest.
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