I 'm trying to extract polysacharides from Aloe leaf and tried ethanol percipitation, but after getting the pellet.
I used the protocol from following reference following the steps, but I don't have access to equipment for lyophilization, therefore I'm stuck it this step. I also tried to dissolve the pellet in distilled water, but didn't work, any suggestion how I can proceed to next steps before using spectrometer for quantification of bioacticve compounds?
Deacetylation affects the physical properties and bioactivity of acemannan, an extracted polysaccharide from Aloe vera (Chokboribal, Tachaboonyakiat et al. 2015)
1- After removing the A. vera skin, the transparent flesh was thoroughly washed to remove the yellow sap.
2- The A. vera gel was cut into 2–3 cm pieces and finely homogenized.
3- The homogenate was centrifuged to separate the soluble part from the insoluble fibrous part.
4- The transparent supernatant was mixed with 3 volumes of absolute ethanol overnight.
5- The resulting white precipitate was collected by centrifugation and lyophilized.
Thanks
Dear Mahnaz Kiani , first you do FINELY , homogenization of the gel, and centrifuge the gel-like material, take soluble (liquid) part out, use 4-5 volume ethanol to precipitate it and leaving it overnight. I think your problem is with centrifuge precipitation speed and time on the 3rd stage. Use higher RPM and more time
Dear Nodirali S. Normakhamatov , thank you for answering my question, if I get it correctly, you mean that I don't get rid of unsolvable stuff after homogenization that prevent the polysaccharids to be dissolve in water later on, right?
May I also ask that what do you recommend instead of lyophilization, I was thinking to dissolve the pellet in deionized water and passed through 0.22 μm filter and store it in -20 freezer. Do you recommend any modification? I really appreciate your time and help!
Exactly. I suppose, your product is a just swellable product in the water yet.
Instead of lyophilization I also see only the precipitation method of the separation. Modification methods are some difficult than that one too. A membrane filtering is also may be difficult because of very hydrophilic polysaccharide content and its molecular weight.
I suggest using ultra-sound treatment after homogenization and particularly dropping the liquid part of polysaccharide fraction to the absolute ethanol and not vice-versa. Use ice-bath for ethanol precipitation process. Just see, if there is going turbidity in each dropping.
Nodirali S. Normakhamatov , thank you so much, I will try your suggestions.
Nodirali S. Normakhamatov Thank you so much for your helpful recommendation, I made some changes including repeating the centrifuge step and getting supernatant with the longer time after homogenization, also used sonication, and it worked perfectly!
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