So many beautiful things in the world, one of them is DAHLIA, a flower which is classified as Compositae family. This herb usually well growth up in the plateau with the cool climate and people just benefit it to make their gardens beautifully and also for business because dahlia is one of preserved flower which can be made as a wedding bouquets.
In spite of that usage, actually Dahlia saves benefits more than that. Dahlia is a tuberous and so many advantages are able to be obtained from this part of plant. It has been well known that Dahlia TUBER contains one of chemical constituent which is called as INULIN. In health, inulin has been used as a prebiotic in health foods, a chemical which stimulates the micro flora growth in our intestine in order to increase our normal food digestion. So, prebiotic will prevent us from gastrointestinal disorder such as constipation, diarrhea, colon cancer, and so on.
structure of inulin
Inulin is a polymer which is composed by β (2→1) and β (2→6) fructosyl fructose chain with less than 200 DEGREE of POLYMERYZATION (DP). Its DP is categorized as a short polymer, means it is easier to decompose this polymer become the small units of monomer. This characteristic can be beneficial for us as we have known that the longer polymer chain such as undegradable plastics having a big problem in our current environmental issues. Beside Dahlia, some plants such as chicory, yacon, garlic, onion, and banana also known containing this constituent.
yacon (Taraxacum officinale)
Regarding the advantages mentioned above, I was interested to study more about Inulin. In my hometown (SOLO, CENTRAL JAVA, INDONESIA), I have 2 nearest plateau which Dahlia was easily found, i.e. TAWANGMANGU and BANDUNGAN. I collected this herb from Bandungan and I selected two varieties only, i.e. WHITE & PURPLE DAHLIA.
Later, I took the tuber part and extract it using water-ethanol as a solvent. The extraction method was using centrifugation followed by purification using precipitation method and charcoal adsorption. The white powder was obtained as a product and I had to analyze it to confirm its molecule structure. I had a PURE CHICORY INULIN got from SIGMA-ALDRICH and used it as a STANDARD REFERENCE. I compared the physical appearance that looked like similar, but the product from white dahlia seemed a bit browning. The solubility of both compounds was also same, and majority were soluble in polar solvent due to the a lot of hydroxyl group presence in the structure
Precipitation of inulin & the obtained products (left (white dahlia); middle (purple dahlia); inulin standard)
The melting point and TLC profile of both my products and standard inulin was exactly similar. Next, the structure was confirmed by using IR spectroscopy. IR spectrum showed the exact same spectra whether at fundamental or fingerprint region between my products & standard inulin. Therefore, I was sure the extraction of inulin from dahlia tuber was done already.
IR spectrum of inulin standard (left) and my product (right),look at the smooth broad band at 4000 cm-1 shows OH group
It was easy to recognize the presence of HYDROXYL GROUP by checking a very smooth broad spectrum at 3000-4000 cm-1 region. Due to this OH group, I interest to modify the structure at this part of molecule in order to decrease the polarity. By acetylating of OH group I predicted that the product would be having Hydrophyl-Lipophyl Balance (HLB). So, it is possible to develop this polymer become a new surface active agent that has been well known to stabilize the disperse system such as emulsion and suspension.
My further research would be acetylating inulin using acetyl chloride as a resource of acetyl group. I was synthesize in two different solvents, i.e. Dimethylformamide (DMF) & PYRIDINE. I avoid the use of polar protic solvent such as water or ethanol due to the instability of acetyl chloride toward hydrolysis or ethanolysis. Thereafter, I reacted my inulin with acetyl chloride under Foam Hoed and the product was isolated using liquid-liquid extraction with ethyl acetate as a solvent and followed by distillation to remove the ethyl acetate from the product.
SNA reaction of inulin with acetyl chloride produces acetylated inulin
The semi-synthetic product was brownish liquid, a bit sticky, insoluble in water, soluble in alcohol and chloroform. Compared to the starting material (Inulin), we can see that it was already different in physical properties, means the product was done. I also run TLC test, IR and H1-NMR spectroscopy to confirm its structure, and done!!! My product showed the sharp band at 1800 cm-1 that was recognized as a STRETCHING VIBRATIONS of -C=O whereas this band was absence at inulin IR spectrum, means the acetylation was successfully done. The 1H-NMR also supported the presence of methyl proton which is adjacent to carbonyl groups.
acetylated inulin (semi-synthetic product)
Comparison 1H-NMR of inulin (starting material) and acetylated inulin (product)
IR NMR of acetylated inulin (product), look at the SHARP BAND at 1800 cm-1 shows the carbonyl group
It is interesting to develop my products become the new suspending agent to enrich the availability of this pharmaceutical inactive ingredients. And surprisingly, when I heated my product at 200C it changed to a kind of plastic matter, and I think being logic since my product was less polar polymer that looks like a plastic. So, may we develop further with these findings? Yah, my product can be developed as BIODEGRADABLE plastics coz only less than 200 of DP it has, therefore it is more friendly to environment. So, ANYBODY interested????
check my published fulltext journal at https://mnh20.wordpress.com/2010/04/12/the-9th-national-symposium-of-polymeric-materials-upm-malaysia/