RESEARCH ARTICLE. Azhar Ahmed 1*, Farukh Khan 1

Transcription

1 Extraction of Starch from Taro (Colocasia esculenta) and Evaluating it and further using Taro Starch as Disintegrating Agent in Tablet Formulation with Over All Evaluation Azhar Ahmed 1*, Farukh Khan 1 Abstract: Taro has been reported to have 70 80% starch with small granules, Because of the small sizes of its starch granules, taro is highly digestible. On the basis of current evaluation of properties of starch it has been found that taro starch can be utilized as a better disintegrant as compared to the other traditional starches, Starches are used since a long time as exipients in pharmaceutical preparations. Mainly maize starch, potato starch and wheat starch are used and monographed in several pharmacopoeias. The classical functionalities of native starches in the past are fillers and disintegrants in tablets and fillers in dermatological powders. Also modified (pregelatinized) starches have been used as filler-binders in tablet technology. After this research activity Taro starch can be introduced in the pharmaceutical field and further more research can be done over this starch to make it highlighted in the arena of pharmaceutical research. In addition to food use, taro has found some industrial applications. The very small size of taro starch granules makes them ideal in cosmetic formulations like face powder and in dusting preparations which use aerosol dispensing systems. In spite of the above uses, the large-scale extraction and utilization of this starch is not practised anywhere. So after this research activity the taro starch can be brought to the minds of researchers and it can gain attention in the field of pharmaceutical research. INTRODUCTION Starch is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store. It is the most common carbohydrate in the human diet and is contained in large amounts in such staple foods as potatoes, wheat, maize (corn), rice, and cassava. It is either used as extracted from the plant and is called native starch, or it undergoes one or more modifications to reach specific properties and is called modified starch. Pure starch is a white, tasteless and odourless powder that is insoluble in cold water or alcohol. It consists of two types of molecules: the linear and helical amylose and the branched amylopectin. Depending on the plant, starch generally contains 20 to 25% amylose and 75 to 80% amylopectin. It is obvious that starch has moved from its traditional role as food to being an indispensable medicine. The wide use of starch in the medicine is based on its adhesive, thickening, gelling, swelling and film-forming properties as well as its ready availability, low cost and controlled quality. From the foregoing, to think that starch is still ordinary inert excipients is to be oblivious of the influence this important biopolymer plays in therapeutic outcome of bioactive moieties. Starch has proven to be the formulator s friend in that, it can be utilized in the preparation of various drug delivery systems with the potential to achieve the formulator s desire for target or protected delivery of bioactive agents. Maize starch, extra white maize starch, wheat starch and potato starch are long-known and reliable excipients used as insoluble diluents that act as fillers in the formulation of tablets and capsules, and as powders for sachets, all while retaining a disintegration function. Generally starch is isolated from potatoes, wheat, maize (corn), rice, and cassava etc. But Starch extraction from 1NRI Institute of Pharmacy, Sajjan Singh Nagar, Raisen Road, Bhopal , M.P., India. azharamd@hotmail.com *Corresponding author Taro (Colocasia esculenta) tuber has not been reported extensively so, The purpose of this study is to extract the starch from Taro (Colocasia esculenta) and evaluating it, and further using taro starch as disintegrating agent in tablet formulation with over all evaluation. In short from this research activity it can be said that taro starch can be introduced to the modern arena of research, and hence it can be proved better and efficient than other natural starches mainly as disintegrant and can be further modified with various researches made over it. Taro 1. Scientific Classification Botanical name: Colocasia esculenta Kingdom: Plantae Order: Alismatales Family: Araceae Sub Family: Aroideae Tribe: Colocasiodeae Genus: colocasia Species: C. esculenta Common names: Taro, Kalo, Eddy root, wild taro, Arvi, Talas. 2. Description [1] A long stalked herbaceous plant with huge leaves, growing to the height of 30 to 150 cms. Rootstock is tuberous up to 10 cm in diameter. The leaves in groups of two or three are long petiolaed, ovate, 20 to 50 cm long, glaucous, with the insertion of the petiole, with broad and rounded basal lobes. Petioles are green or purplish, 0.2 to 1 m long. Spathe is variable in length, about 20 cm long. Spadix is cylindric, half as long as the spathe, green below and yellowish above. 3. Constituents [1] The tuber is chemically composed of vitamin C, thiamine, riboflavin, niacin, oxalic acid, calcium oxalate, pelargodin 3 glucoside, cyaniding 3 rhamnoside, cyaniding 3 glucoside, 1

2 hydroxyl cinnamoyl amides, benzaldehyde 3 4 di O beta glucoside, beta carotene, colocasia sterols, fructose, glucose and sucrose. It also has high starch content. The leaves are rich in calcium phosphate and iron. It contains about 2.26 ppm of iodine. Among the constituents found, there is a bitter substance called acorine which appears to be a nitrogenated glucoside and an aromatic essential oil. 4. Uses [1] a. Medicinal Use Taro was used by Hawaiians to treat illness ranging from constipation to tuberculosis. It is used as a laxative in cases of haemorrhoids. The raw juice mixed with sugar was taken orally to reduce fever. The leaves of the plant are rich in vitamins A, B and C and were used to treat asthma. Taro is good for people allergic to milk or cereals and can be consumed by children who are sensitive to milk. It acts as a probiotic because it contains the predominant lactic acid bacteria. Studies have been reported its possible beneficial role in the treatement of diarrhoea, gastroenteritis, irritable bowel syndrome and inflammatory bowel disease, cancer, depressed immune function and inadequate lactase digestion. In Philippines, taro leaves and corms were boiled and eaten by women experiencing a difficult childbirth. Some tribes use taro as an antidote to the stings of wasps and other biting insects, heated tubers were applied to painful parts in rheumatism. Honey mixed with tuber ash was also used as a cure for apthae in the mouth. b. Industrial Use Although it was not common in practice, the petioles were sometimes used to make dots of semicircle designs on cloth. In fact, certain varieties were used as a source of red kapa dye. Taro starch is used in the manufacture of biodegradable plastics. c. Food Source The starch contained in the large corms of taro is highly digestible, therefore making it a good source for carbohydrate and to a lesser degree a source of potassium and protein. MATERIALS AND METHODS Experimental Work Experimental work of this Research activity consists of the following sections: 1. Collection of tuber 2. Extraction of starch from tubers 3. Preliminary testing of starch 4. Formulation of tablet using extracted starch as disintegrating agent 5. Overall evaluation of starch and its properties Collection of Tubers and Identification Tubers were collected locally from Bhopal. Herbarium was prepared and submitted at botany department of Saifia College, Bhopal for authentication. The botanical identity of the plant was confirmed by Dr. Zeaul Hasan. (Assistant professor) and authentification of plant is 257/Bot/saifia/12. Tubers were washed and air dried. Dried tubers part of Colocasia esculenta were crushed to fine powder using grinder at N.R.I. Institute of Pharmacy, Bhopal and stored in an air tight container for further studies. Extraction of Starch from Tubers Taro tubers was collected and cleaned properly washed. After washing outer covering layer was peeled. The tuber was than sliced and kept for drying at room temperature. After drying, the dried sliced tuber pieces were crushed in mixer grinder to form the powder. This powder is further used for extraction of starch. Starch was extracted by three methods which are as follows; 1. Extraction by Simple Process Taro powder (50 gm) was taken and dispersed in 100 ml of water; the mixture was homogenized for about 30 mins, by using homogenizer. Resulting solution was kept overnight. On next day the solid and liquid layer gets separated, solid material gets deposited at the bottom of the glass beaker while the liquid floats at upper surface. The liquid layer is decanted and remaining sediment is washed with excess of water. After washing the water is decanted and the starch powder is obtained by filtration through whattman filter paper, powder is kept for drying. The obtained powder after drying is starch powder. 2. Wet Milling Process [2] Taro powder (50 gm) was steeped in a sodium metabisulphite solution (150 ml, 0.45% W/V) overnight in a refrigerator. Now the slurry is was milled using a commercial food blender for 5 min. The blended slurry was mixed with 450 ml NaCl solution (0.1 M) and 50 ml Toulene. The mixture was stirred for 1hr and then allowed to stand until the starch granules settled at the bottom. The protein in toluene and NaCl solution layers was siphoned off and discarded, and this was repeated until all of the proteins were removed as indicted by a clear toluene layer after the starch granules settled at the bottom. The starch layer was then washed with water several times and subsequently with absolute ethanol. The wet milled starch was then recovered by filtration through Whatman filter paper, rinsed with ethanol and air dried. 3. Centrifugation Process [3] Taro powder (20 gm) steeped in 50 ml of 1% sodium metabisulphite solution at 45 C for 24, 48 or 72 hours. The liquid phase is separated. The separated slurry paste was placed in a 50 ml centrifuge tube with 10 ml of distilled water and homogenized using a homogenizer for 30 sec. The homogenized slurry was filtered by using a fine nylon filter under vacuum with several washes for a total wash water volume of 500 ml. Coarse and fine fibers and a part of protein were removed during filtration. The starch protein mixture from the filtrate was further separated by either centrifugation or sedimentation. (In this case centrifugation performed). 2

3 Figure 1: Globules of starch extracted by centrifugation Figure 2: Globules of starch extracted Figure 3: Globules of starch extracted Figure 4: Globules of corn starch Table 1: Observations of Physical Tests Types of Starch Extract Normal Wet milling Centrifugation Bulk Density Tapped Density 0.33 gm/cm gm/cm gm/cm 3 gm/cm gm/cm 3 gm/cm 3 Moisture Content (IR Balance) 1.7% L.O.D 1.6% L.O.D 1.6% L.O.D Particle Size Angle of Repose Melting Point (Thieles Tube Apparatus ) 266 ±2 C 268±2 C 268±2 C Table 2: Observations of Chemical Tests Types of Starch Extract Benedict Test Molish Test Legal Test Reducing Sugar Protein Test (Sugar) (Carbohydrate) (Glycoside) Test Normal positive positive positive Negative Negative Wet Milling positive positive positive Negative Negative Centrifugation positive positive positive Negative Negative Centrifugation: The starch slurry was centrifuged for 30 mins. The supernatant was decanted, the protein layer was scraped off and more water added to the partly cleaned starch, with centrifugation and decanting repeated three times. The resulting sediment was air dried. Preliminary Testing of Extracted Starch Preliminary testing of starch is done by evaluation of various physical and chemical parameters. The results of preliminary study are shown in Table 1 and Table 2. While particles size is shown in Figures 1, 2, 3 and 4 respectively. Formulation of Tablet Using Extracted Starch as Disintegrating Agent Formulation of placebo tablets is formulated by using standard corn starch and extracted taro starch as disintegrating agents with other exipients. Later on tablet was prepared by direct compression, dry granulation and wet granulation methods. 1. Formula [4] Ingredient Quantity 1. Microcrystalline cellulose (binder) 38.4 gm 2. Lactose (filler) 38.4 gm 3

4 Table 3: Evaluation of Tablets Made From Taro Starch which is Extracted by Simple Process with Water (Tablet A) Disintegration Time Wt. Variation (Kg/cm 2 ) Direct Compression Dry Granulation Wet Granulation Table 4: Evaluation of Tablets Made from Taro Starch which is Extracted by Centrifugation Process (Tablet B) Wt. Variation Disintegration Time (kg/cm 2 ) Direct Compression Dry Granulation Wet Granulation Table 5: Evaluation of Tablets made from Taro Starch which is Extracted by Wet Milling Process (Tablet C) Wt. Variation Disintegration Time (kg/cm 2 ) Direct Compression Dry Granulation Wet Granulation S. No. Property Table 6: Evaluation of Tablets, Taro Starch Tablet Compared with Reference Tablets Selected Tablet of Taro Starch (Tablet C, Wet Granuled) Potato starch Tablet Corn Starch Tablet 1. (Kg/cm 2 ) Weight variation % % Disintegration Time Starch (disintegrant) 2.4 gm 4. Magnesium stearate (lubricant) 800 mg 2. Preparation of Placebo Tablets by Direct Compression Compressed tablets were prepared by direct compression method employing starch as disintegrating agent. All the materials required as per the formulae were blended in a closed polyethylene bag. The blends were compressed into tablets on a tablet punching machine to a hardness of 10 kg/cm2 using round and flat punches. In this case, 30 tablets were compressed. 3. Preparation of Placebo Tablets by Wet Granulation Accurately weighed quantities of each ingredient were mixed in a mortar and an appropriate quantity of the microcrystalline cellulose (with distilled water) was added as a granulating agent and mixed for 20 min in a mortar. The damp mass was sieved with sieve no. 22 and dried at 50 C in an oven for 6 hrs. The dried granular mass was passed through sieve no. 40 to obtain uniform sized granules. The batch of the granules and specified amount of the disintegrant i.e. Taro starch were then mixed with calculated equal quantity of magnesium stearate and then compressed into tablets under constant pressure with a rotary tablet machine. 4. Preparation of Placebo Tablets by Dry Granulation Milling of different components is done, proper quantity of ingredients are milled. Mixing of milled powders is done as a followed by sieving with sieve No. 22, now after mixing compression is done into large hard tablets to make slug. After obtaining slugs, Screening of slugs is done followed by crushing them and again screening of the crushed slugs by using a sieve of no. 40. The screened powder is the mixed with screened lubricant and disintegrating agent powder and finally the tablet is compressed or punched by using rotary tablet punching machine Evaluation of Tablets 1. Test Five tablets were selected at random from each batch to perform this test. Pfizer hardness tester (Elite, Mumbai, India) was used to measure the hardness. Tablet was placed between spindle and anvil of the tester and the calibrated scale adjusted to zero, then diametric compression force was applied on the tablet and the position on the calibrated scale at which the tablet broke was recorded in kg units. A mean hardness was calculated for each batch. 2. Weight Uniformity Test 4

5 Twenty tablets were selected randomly from each batch and weighed. The mean weights were calculated for each batch. 3. Test Ten tablets were selected randomly, dusted, weighed together and then placed in the friabilator. The machine was operated for 100 rotations at 25 rpm and then stopped. The tablets were dusted and again reweighed. The percentage losses were calculated. f=i-f*100/i Where, I=initial weight of tablets, F=weight after friability. Normal limits less than 1%. 4. Disintegration Time [5] According to the method specified in the USP/NF (1980), 100 ml of 0.1 N HCl was used as disintegration medium at temperature 37±2 C throughout the experiment. Randomly selected five tablets from each batch were placed one in each of the cylindrical tubes of the basket but no disc was used. The time taken for each tablet to break up into small particles and pass out through the mesh was recorded. Mean disintegration time was calculated for each batch. The results of evaluation are shown in Table 3, Table 4 and Table 5. NOTE 1: During punching of the tablets it was found that the granules which was prepared by wet granulation process are getting easily filled in the dyes and the tablets which are produced from wet milled taro starch (Tablet C) are of good property and uniform as compared to the tablets which are made from granules of direct compression and dry granulation process. So for the further process the wet granulated tablet C are used. NOTE 2: Potato and corn starch tablets are formulated as reference tablets, formula is used same as of taro starch tablets just the difference is that taro starch is replaced with Potato and corn starch, And tablets was made by wet granulation process. Results of taro starch tablet compared with potato and corn starch tablet are shown in Table 6. RESULTS Starch has been extracted from Taro successfully by three methods of extraction and it has been found that the starch which is extracted by wet milling method shows better property as compared to other two methods. Tablets which are prepared from wet milled extracted starch by wet granulation process shows better disintegration. And after comparison with standard reference tablets i.e. potato and corn starch placebo tablets, the taro starch tablet shows better disintegration as compared to the reference tablets due to this it can be proved that the taro starch is a better disintegrant as compared to the other natural starches. CONCLUSION The present study reveals that results obtained showed some differences on the properties of the starch obtained from Taro and other traditional starch sources like potato and corn. Taro has been reported to have 70 80% starch with small granules, Because of the small sizes of its starch granules, taro is highly digestible. On the basis of current evaluation of properties of starch it has been found that taro starch can be utilized as a better disintegrant as compared to the other traditional starches, Starches are used since a long time as exipients in pharmaceutical preparations. Mainly maize starch, potato starch and wheat starch are used and monographed in several pharmacopoeias. The classical functionalities of native starches in the past are fillers and disintegrants in tablets and fillers in dermatological powders. Also modified (pregelatinized) starches have been used as filler-binders in tablet technology. After this current research activity Taro starch can be introduced in the pharmaceutical field and further more research can be done over this starch to make it highlighted in the arena of pharmaceutical research. In addition to food use, taro has found some industrial applications. The very small size of taro starch granules makes them ideal in cosmetic formulations like face powder and in dusting preparations which use aerosol dispensing systems. In spite of the above uses, the largescale extraction and utilization of this starch is not practised anywhere. So after this research activity the taro starch can be brought to the minds of researchers and it can gain attention in the field of pharmaceutical research. REFERENCES AND NOTES 1. Martin, Cyanophoic Glycosides, 3G Pharmacy. Acs publication, Z A Syahariza, Enpeng Li, Jovin Hasjim. Extraction and dissolution of starch from rice and sorghum grains for accurate structural analysis. Carbohydrate Polymers, 82:14 20, Y Ji, K Seetbaraman and P J White. Optimization of small scale corn starch extraction method for use in the library. Journal of Cereal chemistry, 81(1):55-58, Bruno C Hancock, Joshua T Colvin, Matthew P Mullarney, Andrey V Zinchuk. The Relative Densities of Pharmaceutical Powders, Blends, Dry Granulations, and Immediate-Release Tablets. Journal of pharmaceutical technology, 64-80, Elevina Perez, Forrest S Schultz, Emperatrı z Pacheco de Delahaye. Characterization of some properties of starches isolated from Xanthosoma sagittifolium (tannia). Carbohydrate polymers, 60, , Cite this article as: Azhar Ahmed, Farukh Khan. Extraction of Starch from Taro (Colocasia esculenta) and Evaluating it and further using Taro Starch as Disintegrating Agent in Tablet Formulation with Over All Evaluation. Inventi Rapid: Novel Excipients, 2013(2):1-5,