Title of Invention

A PROCESS FOR THE EXTRACTION OF STABLE GREEN DYE FROM ECLIPTA ALBA

Abstract

A process for the extraction of stable green dye from Eclipta alba by extraction of plant material using a non polar solvent to obtain defatted plant material, extraction of defatted plant material using a polar solvent followed by filtration and concentration under vacuum at a pressure in the range of 50-70 cm Hg and temperature in the range of 50-70°C to obtain a polar solvent extract, extraction of the polar solvent extract using organic solvents followed by filtration and concentrating the filtrate under vacuum at a pressure in the range of 50-70 cm Hg and temperature in the range of 30-50°C, reextration of concentrate obtained from step c) using organic solvent followed by filtration and concentration under vacuum at a pressure in the range of 50-70 cm Hg and temperature in the range of 50-70°C.

Full Text

The present invention relates to an improved process for the extraction of stable green dye from Eclipla a/ha. Natural sources can provide a comprehensive range of attractive colours viz. green , blue, purple, violet ,red and orange . Clllorophylls are the only natural green plant pigment and certainly the only ones in super abundance. Unfortunately , the inherent instability of chlorophylls in isolation has been a drawback to their more widespread application as food colorants . The production and use of chlorophylls as food colorant has become increasingly important in recent years , The challenging opportunities for new production methods and new products may help lo promote the wider use of this colourful group of pigments . Chlorophylls entering the food - colorant market are derived from land plants which , in recent decades , have included lucerne, or alfaalfa (Medicago saliva} , nettles (Unica tlioica) or several high -yielding pasture grassesfNalural Food Colorants , eds G. A. F, , Hendry and J. D. Houghton , Blackie and Son Ltd., 1992 , pp. 79). One notable exception has been the use in Japan of the green faeces of the silk- worm where the larvae feed on mulberry leaves and excrete chlorophyll, among other pigments (Natural Food Colorants , eds G. A. F., Hendry and J. D. Houghton , Blackie and Son Ltd, 1992 , pp. 79). Kdipta alba (L.) Husk, is a small , branched annual herb with white flower heads inhabiting tropical and subtropical regions of the world . In India, the plant is widely distributed as weed in moist situation , ascending upto 6000 ft on the hills (Chopra, R. N. ,Nayar, S. L. and Chopra, I. C., Glossary of Indian Medicinal Plants (1952), 127-128).£. alba is commonly known as safed bhangra when in flower and as kala bhangra when in fruit. In Ayurvedic medicine , Eclipta alba is said to be the best drug for the treatment of liver cirrhosis and infective hepatitis (Dixit, S. P., Achar, M. P., J. Sci. Res. Planta Med. (1981) 2 ,96). A preparation obtained from the juice of the leaves boiled with sesamum or coconut oil is used for anointing the head to render the hair black and luxuriant . The fresh plant is considered anodyne and absorbent . It is rubbed on the gums toothache and applied with a little oil for relieving headache . Its extract with sesamum oil is also applied in elephantiasis . The plant is used as a dyeing herb in tattooing . (The Wealth of India, Raw Materials, vol.III (1952), 127-128). Although the plant Eclipia alba is used traditionally to dye the hair , no method of extraction of its green dye is available. The main object of the present invention is to provide a process for the extraction of stable green dye from Eclipta alba. Another object of the present invention is to provide a quick, efficient and economical process for the extraction of green dye from Eclipta alba. Eclipta alba , abundantly distributed throughout India ,was collected from Lucknow region. Dried plant material was defatted using hexane followed by extraction using a non - toxic solvent such as ethanol. The concentrated extract, thus obtained, was fractionated using various solvents to give a green dye which was stable for a long period. Accordingly, the present invention provides a process for the extraction of stable green dye from Eclipta alba which comprises : a) extraction of plant material using a non polar solvent to obtain defatted plant material, b) extraction of defatted plant material using a polar solvent followed by filtration and concentration under vacuum at a pressure in the range of 50-70 cm Hg and temperature in the range of 50-70°C to obtain a polar solvent extract, c) extraction of the polar solvent extract using organic solvents such as herein described followed by filtration and concentrating the filtrate under vacuum at a pressure in the range of 50-70 cm Hg and temperature in the range of 30- 50°C, d) reextration of concentrate obtained from step c) using organic solvent followed by filtration and concentration under vacuum at a pressure in the range of 50-70 cm Hg and temperature in the range of 50-70°C. In an embodiment of the present invention the nonpolar solvent used for extraction may be selected from petroleum ether, hexane, benzene and mixtures thereof. In another embodiment the extraction may be effected for a period of 50 to 100 hours. In yet another embodiment the polar solvent used for extraction may be selected from ethyl acetate, methanol, ethanol, water and mixtures thereof. In still another embodiment the organic solvent used may be selected from diethyl ether, ethyl acetate, chloroform, carbon tetrachloride and mixtures thereof. In still another embodiment the organic solvent used for reextraction may be selected from carbon tetrachloride, ethyl acetate, chloroform, acetone and mixtures thereof. In still another embodiment of the invention the green dye extracted from E. alba using the process of invention, has the following characteristics; a : colour-bright green ; b : absorption maxima 470, 625,662nm; c : solubility- acetone, methanol, ethanol, diethyl ether, carbon tetra chloride; d : stability- more than six months. In still another embodiment of the invention the weed used for extraction of stable green dye may be such as Ecliplaalba. The following examples illustrate the process of the present invention. However, these should not be construed to limit the scope of the present invention. Example -I Fresh Bhringraj (Edipta alba) was shade dried, crushed into small pieces and 500g of dried material was defatted using hexane. The defatted plant material was then extracted using ethyl alcohol for 72 hours. The process of extraction was repeated thrice and the mixed extract was concentrated under vacuum at a temperature of 50T and pressure 60 cm Hg . The above alcoholic concentrate was extracted with diethyl ether, concentrated under vacuum at 30°C temperature and 50 cm Hg pressure . The concentrated ether extract was purified by extraction with carbon tetrachloride to give a green dye in a yield of 1.5 percent . The absorption maxima was measured weekly and a constant stability in the colour was achieved for a period of more than six months; colour-bright green ; absorption maxima 470, 625, 662; solubility- acetone, methanol, ethanol, diethyl ether, carbon tetra chloride; stability- more than six months. Example-II Fresh Bhringraj (Eclipta alba) was shade dried, crushed into small pieces and 500g of dried material was defatted using hexane. The defatted plant material was then extracted using ethyl alcohol for 50 hours. The process of extraction was repeated thrice and the mixed extract was concentrated under vacuum at a temperature of 50°C and pressure 60 cm Hg . The above alcoholic concentrate was extracted with diethyl ether , concentrated under vacuum at 30°C temperature and 50 cm Hg pressure . The concentrated ether extract was purified by extraction with carbon tetrachloride to give a green dye in a yield of 1.5 percent . The absorption maxima was measured weekly and a constant stability in the colour was achieved for a period of more than six months; colour-bright green ; absorption maxima 470, 625, 662; solubility- acetone, methanol, ethanol, diethyl ether, carbon tetra chloride; stability- more than six months. Example -III Fresh Bhringraj (Ei-lipta ii!bu) was shade dried, crushed into small pieces and 500g of dried material was defatted using hexane. The defatted plant material was then extracted using ethyl alcohol for 50 hours. The process of extraction was repeated thrice and the mixed extract was concentrated under vacuum at a temperature of 70"C and pressure 60 cm Hg . The above alcoholic concentrate was extracted with diethyl ether , concentrated under vacuum at 30°C temperature and 50 cm Hg pressure . The concentrated ether extract was purified by extraction with carbon tetrachloride to give a green dye in a yield of 1.5 percent. The absorption maxima was measured weekly and a constant stability in the colour was achieved for a period of more than six months; colour-bright green ; absorption maxima 470, 625, 662; solubility- acetone, methanol, ethanol, diethyl ether, carbon tetra chloride; stability- more than six months. Example-IV Fresh Bhringraj (Eclipta alba) was shade dried, crushed into small pieces and 500g of dried material was defatted using hexane. The defatted plant material was then extracted using ethyl alcohol for 72 hours. The process of extraction was repeated thrice and the mixed extract was concentrated under vacuum at a temperature of 50°C and pressure 60 cm Hg . The above alcoholic concentrate was extracted with diethyl ether , concentrated under' vacuum at 50°C temperature and 50 cm Hg pressure . The concentrated ether extract was purified by extraction with carbon tetrachloride to give a green dye in a yield of 1.5 percent . The absorption maxima was measured weekly and a constant stability in the colour was achieved for a period of more than six months; colour-bright green ; absorption maxima 470, 625, 662; solubility- acetone, methanol, ethanol, diethyl etlter, carbon terra chloride; stability- more than six months. Example -V Fresh Bhringraj (Eclipta alba) was shade dried, crushed into small pieces and 500g of dried material was defatted using hexane. The defatted plant material was then extracted using ethyl alcohol for 72 hours. The process of extraction was repeated thrice and the mixed extract was concentrated under vacuum at a temperature of 50°C and pressure 60 cm Hg . The above alcoholic concentrate was extracted with diethyl ether , concentrated under vacuum at 30°C temperature and 70 cm Hg pressure . The concentrated ether extract was purified by extraction with carbon tetrachloride to give a green dye in a yield of 1.5 percent . The absorption maxima was measured weekly and a constant stability in the colour was achieved for a period of more than six months; colour-bright green ; absorption maxima 470 625, 662; solubility- acetone, methanol, ethanol, diethyl ether, carbon terra chloride; stability- more than six months. Example -VI Fresh Bhringraj (Edipta alba) was shade dried, crushed into small pieces and 500g of dried material was defatted using hexane. The defatted plant material was then extracted using ethyl alcohol for 72 hours. The process of extraction was repeated thrice and the mixed extract was concentrated under vacuum at a temperature of 50°C and pressure 70 cm Hg . The above alcoholic concentrate was extracted with diethyl ether , concentrated under vacuum at 30°C temperature and 70 cm Hg pressure . The concentrated ether extract was purified by extraction with carbon tetrachloride to give a green dye in a yield of 1.5 percent. The absorption maxima was measured weekly and a constant stability in the colour was achieved for a period of more than six months; colour-bright green ; absorption maxima 470, 625, 662; solubility- acetone, methanol, ethanol, diethyl ether, carbon tetra chloride; stability- more than six months. In the claimed invention the selection of solvents in various extraction sequences is critical in achieving the stability of the green dye from E.alba .This is further proved by experimentations done by us where several problems like * lesser stability and yield was observed as explained below : A- Dried plant (500g) was defatted using hexane and then extracted using ethanol , concentrated under vacuum , extracted with hexane , concentrated and again extracted with carbon tetrachloride to give a stable green dye but in a very poor yield (0.3%) B- Dried plant (500 g) was defatted using hexane, followed by extraction using ethyl acetate, concentration under vacuum, extraction with diethyl ether, concentration under vacuum and again extraction with carbon tetrachloride to give a green dye .The dye was stable but the yield was poor (0.8%). C- Dried plant (500 g) was defatted using hexane, extracted with ethanol, concentrated, again extracted with diethyl ether and concentrated to give a green dye in a yield of 2.0% but lacks stability of colour after 2 weeks. D- Dried plant (500 g) was defatted with hexane and then extracted with ethanol, concentrated, extracted with diethyl ether , concentrated -, again extracted with chloroform to give a green dye (2.0%) but lacks stability of colour after 2 weeks. The present invention has following advantages: This process is simple and no costly chemical is required . A bright and stable green dye was achieved. Moreover, the colour can be stored for a long period. We claim : 1. A process for the extraction of stable green dye from Eclipta alba which comprises : a) extraction of plant material using a non polar solvent to obtain defatted plant material, b) extraction of defatted plant material using a polar solvent followed by filtration and concentration under vacuum at a pressure in the range of 50-70 cm Hg and temperature in the range of 50-70°C to obtain a polar solvent extract, c) extraction of the polar solvent extract using organic solvents such as herein described followed by filtration and concentrating the filtrate under vacuum at a pressure in the range of 50-70 cm Hg and temperature in the range of 30-50°C, d) reextration of concentrate obtained from step c) using organic solvent followed by filtration and concentration under vacuum at a pressure in the range of 50-70 cm Hg and temperature in the range of 50-70°C. 2. A process as claimed in claim 1 wherein the nonpolar solvent used for extraction is selected from petroleum ether, hexane, benzene and mixtures thereof. 3. A process as claimed in claims 1-2 wherein the extraction is effected for a period of 50 to 100 hours. 4. A process as claimed in claims 1-3 wherein polar solvent used for extraction is ethyl acetate, methanol, ethanol, water and mixtures thereof. 5. A process as claimed in claims 1-4 wherein the organic solvent used in stepfc) is diethyl ether, ethyl acetate, chloroform, carbon tetrachloride and mixtures thereof. 6. A process as claimed in claims 1-5 wherein the organic solvent used for reextraction in step(d) is carbon tetrachloride, ethyl acetate, chloroform, acetone and mixtures thereof. 7. A process for the extraction of stable green dye from Eclipta alba substantially as herein described with reference to the examples.

Documents:

234-del-1999-abstract.pdf

234-del-1999-claims.pdf

234-del-1999-correspondence-others.pdf

234-del-1999-correspondence-po.pdf

234-del-1999-description (complete).pdf

234-del-1999-form-1.pdf

234-del-1999-form-19.pdf

234-del-1999-form-2.pdf

234-del-1999-form-3.pdf

234-del-1999-petition-138.pdf