Adsorption of Cationic Methylene Blue and Anionic Methyl Orange by Crude Drug Starches

Yoshihide Yamada, Keito Boki, Akiko Matsuyama, Masae Takahashi, Masahiro Iwaki
2005 Journal of Applied Glycoscience  
Crude drugs are used as raw materials for powdered crude drugs or extracts at pharmaceutical factories. In 1988, the amounts of PG, PT, AO and CL consumed in Japan were 954, 670, 247 and 330 tons, respectively, an increase of approximately 3 to 7 fold compared to the year 1978. 1) In 2002, the quantitative imports of PG, PT, AO and CL were 876, 250, 200 and 6972 tons, respectively. 2) More consumption of crude drugs is estimated in the field of health foods or cosmetics. After a crude drug is
more » ... tracted with a solvent, its residue now is reused as a compost or incinerated. The crude drugs PG, PN, PT, AO and CL contain 5.5 12.9% starch by weight. 3) However, there has been almost no research on the adsorption of dyes by crude drug starches except for kudzu starch. 4) The adsorption properties of crude drug starches were investigated in an attempt to make profitable the use of starch from the extracted residues. The adsorption of dye by starch is important for the coloring of bean jam cakes and starch confectioneries. The isotherm for the adsorption of anionic dyes by cereal starches 5) and that of ferric chloride (cationic) by potato, corn and cassava starches 6) were found to fit the Langmuir equation. Both the Langmuir and Freundlich equations were applicable to the isotherm of anionic dye. 4) However, the adaptability of an adsorption equation has been evaluated based on a partial or uniform weighting of the amount adsorbed and residual concentration. 4 6) In the present study, a statistical analysis on the isotherm was performed using Akaike s information criterion (AIC) value 7) to solve this problem. The extent of the adsorption of anionic dyes by starches was related to the ratio of amylopectin to amylose 5) or the amount of phosphorus content. 4) In this study, the factors responsible for the difference in amounts of cationic methylene blue (MB) and anionic methyl orange (MO) adsorbed were discussed, and a crude drug starch superior in the capacity to adsorb both cationic and anionic dyes was identified. MATERIALS AND METHODS Materials. The crude drug starches (S) of PG, PN, PT, AO and CL and potato starch (S ST) were the same as those used previously. 2) The starch was deproteinized by the method of Suzuki et al . 8) and defatted by the method of Schoch. 9) The starch was screened with 400 mesh or less and kept in tight containers. Reagent grade MB and MO were obtained from Wako Pure Chemicals, Osaka, Japan. All other reagents were of the highest grade commercially available. Adsorption procedure. About 150 mg of starch was weighed accurately and added to a hermetic glass con-Abstract: In order to use effectively the starch from the extracted residue of crude drugs, adsorption characteristics of cationic methylene blue (MB) and anionic methyl orange (MO) were investigated. Starches (S) were prepared from the roots of Panax ginseng C.A. Meyer (PG) and Panax notoginseng (Burk.) F.H. Chen (PN), the rhizomes of Pinellia ternate (Thunb.) Breitenbach (PT) and Alisma orientale Juzepczuk (AO), and the seeds of Coix lacrymajobi Linne var. ma-yuen Stapf (CL). The adsorption isotherm was evaluated using Akaike s information criterion (AIC) value, and the adsorption of cationic MB and anionic MO by the starches was classified into the Langmuir type and Freundlich type, respectively. The starches adsorbed more MB than MO. The amounts adsorbed were affected not by the particle size or the content of cationic minerals, but by the phosphorus content. Cationic MB was adsorbed more strongly than anionic MO on the negatively charged surface of the starches because of the presence of phosphorus. S-CL was superior in adsorption capacity for both cationic MB and anionic MO to S-PG, S-PN, S-PT, S-AO, and S-ST (potato starch) at 5 and 25 C. S-CL had a porous and stripe structure on the granular surface, and contained a small amount of phosphorus. Key words: cationic methylene blue, anionic methyl orange, crude drug starch, applicability of adsorption equation, reuse of crude drug residue Corresponding author (Tel. 81 6 6722 0586, Fax. 81 6 6721 1313, E mail: t3a3k1e4@osk.3web.ne.jp). Abbreviations: MB, methylene blue; MO, methyl orange; S, starch; PG, root of Panax ginseng C.A. Meyer; PN, root of Panax notoginseng (Burk.) F.H. Chen; PT, rhizome of Pinellia ternate (Thunb.) Breitenbach; AO, rhizome of Alisma orientale Juzepczuk; CL, seed of Coix lacrymajobi Linne var. ma yuen
doi:10.5458/jag.52.101 fatcat:lhfd72h3zrb2douhj5ni73lica