Sponge protein hydrolysates and methods of producing the same

Abstract: A sponge protein hydrolysate is produced using sponge skeleton fibers (spongin fibers) refined from sponges as the raw material, by carrying out hydrolysis using an acidic solution, in which the pH is adjusted to 1 using an electrolytic acidic water with a pH of less than 2.5 and oxidation-reduction potential of more than 1,000 mV mixed with an acid, to reduce the molecular weight of sponge proteins to less than 5,000.

Description: The present invention relates to sponge protein hydrolysates which are obtainable by hydrolyzing sponge skeleton fibers (spongin fibers) obtained from sponges of Spongia which belongs to Porifera, with light coloring. The present invention also relates to the use of sponge protein hydrolysates as a raw material having a human cell growth stimulating effect in cosmetics, medicinal products and food products. Furthermore, the present invention relates to methods of producing sponge protein hydrolysates by hydrolyzing sponge skeleton fibers obtained from sponges of Spongia which belongs to Porifera, with light coloring. In the conventional utilization of poriferans (phylum Porifera), spongin fibers obtained from sponges of family Spongia (order Keratosa, class Demospongea) comprise odorless, soft and highly absorbent spongy structures and have long been used as an absorbent for water, a dusting material for lithographs, a cleansing material for babies or an applicator for cosmetics. Recently, attention has been drawn to the more value-added use of sponge components, and anti-cancer components, protein adsorbing enzymes or the like have been extracted from sponges. Analysis shows that the spongin fiber component of family Spongia consists of marine proteins rich in amino acids such as glycine, aspartic acid, glutamic acid, proline and arginine, which are effective in human cell growth stimulation when used as cosmetics, medicinal products and food products. However, little is known about the technology for utilizing marine protein hydrolysates derived from sponges in cosmetics, medicinal products, food products or the like. Conventionally, a collagen slurry obtained by hydrolyzing proteins of animals, such as calves, with a strong alkali had drawn attention for use in cosmetics or medicinal products, but its use is now-intentionally suspended in many countries because of possible contamination with mad cow disease (bovine spongiform encephalomyelitis, BSE). Since the poriferan is a marine animal and bears no contamination problem, its use has drawn greater attention. Since sponges are rich in amino acids which are effective in human cell growth stimulation, attention is being focused on the value-added use of spongin fibers in cosmetics, medicinal products or food products in which glycine, aspartic acid, glutamic acid, proline or arginine of the spongin fibers are effective components. However, no method for their satisfactory use has been found. The present inventors had developed a method for their use in which a sponge protein hydrolysate is obtained by making an acid solution or alkaline solution, or using protein hydrolases, and filed for a patent (Japanese Patent Application No. 1999/010702). However, some improvement was required for their use. A method of hydrolyzing animal proteins by heating under strong alkaline or acidic conditions is known. However, there are some problems in this method, in that the coloring of sponge hydrolysates is intensive and cannot be removed even with activated carbon, that the solids concentration in the lightly colored extract solution can be only 2 to 3% by weight and that the extraction yield is as low as 50% at most. If proteins extracted from sponges have a molecular weight of more than 5,000, the cell growth stimulating effect on skin or hair is low and only a slight therapeutic effect is expected. Furthermore, these proteins have low moisture-retaining efficacy and cannot protect skin or hair. Therefore, it is important to reduce the molecular weight to less than 5,000, which conventionally requires complicated processes such as hydrolysis using proteases, and purification of an extract is laborious. According to the present invention, the problem of the coloring of the hydrolysate is solved, and a hydrolysate having a molecular weight of less than 5,000 can be obtained at high yield without using a protein hydrolase. The present invention provides a method of producing a sponge protein hydrolysate wherein the hydrolysis is carried out using an acidic solution in which the pH is adjusted to 1 using electrolytic acidic water with a pH of less than 2.5 and an oxidation-reduction potential of more than 1,000 mV admixed with an acid to obtain sponge proteins having a molecular weight of less than 5,000, using sponge skeleton fibers (spongin fibers) refined from sponges as the raw material. Furthermore, the present invention provides a sponge protein hydrolysate obtainable by the above-described method. In addition, the present invention provides the use of a sponge protein hydrolysate as described above as a raw material having a human cell growth stimulating-effect in cosmetics, medicinal products and food products. Further aspects of the present invention are described in the dependent claims. The method of the present invention uses spongin fibers obtained from sponges of Spongia which belongs to Porifera (hereinafter referred to as Spongia sponges), as the raw material. Spongia sponges are preferably refined to remove impurities and soils and then crushed before hydrolysis. Spongia sponges are soaked, with heating, in an acidic solution in which the pH is adjusted to 1 using electrolytic acidic water with a pH of less than 2.5 and an oxidation-reduction potential of more than 1,000 mV admixed with an acid to carry out hydrolysis to obtain sponge proteins having a molecular weight of less than 5,000, with light coloring. After the hydrolysis, the hydrolysate is neutralized using sodium hydroxide and desalted using a reverse osmotic membrane or ion-exchange resins. For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein. Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow. These and other features of this invention will now be described with reference to the drawings of preferred embodiments which are intended to illustrate and not to limit the invention. Figure 1 shows the effect of the control sample on the hair cuticle. The photograph shows hair on which the control solvent was applied and then treated with the bleaching agent. The cuticle is loosened and apparent damage can be observed. Figure 2 shows the effect of the sponge extract solution of the present invention on the hair cuticle. The photograph shows hair which was pretreated with the sponge extract solution. The hair is firmly covered with the cuticle and virtually no damage caused by the bleaching agent can be observed. This confirms that the sponge extract solution suppressed the damage caused by the bleaching agent. Figure 3 shows the effect of the reference sample, hydrolyzed collagen, on the hair cuticle. The photograph shows hair which was pretreated with the hydrolyzed collagen solution. Slight damage caused by the bleaching agent is observed. In the present invention, the electrolytic acidic water to be used can be obtained from the anode chamber during electrolysis with the addition of sodium chloride to water. It contains a high concentration of hydrogen ions and hypochlorous acid and has bleaching and pasteurizing effects. The electrolytic acidic water to be used for the present invention can be obtained using a device such as a Suntron-type MWH-1 (a product of Koshin), Calios (a product of Japan Carlit Co. Ltd.) or Oasysbio (a product of Asahi Glass Engineering Co. Ltd.). Examples of acids to be used in the present invention include hydrochloric acid, sulfuric acid, nitric acid, oxalic acid, acetic acid, citric acid and malic acid. The pH of the acid solution to be used is adjusted to 1 with the acid and electrolytic acidic water. The amount of the acidic solution to be used can be 25 to 50 times the weight of the Spongia sponges. The sponges are soaked in the acidic solution and heated at 80 to 90°C for 6 to 8 hours to carry out hydrolysis with light coloring. According to the present invention, the hydrolysis produces sponge proteins having a molecular weight of less than 5,000 and the yield is appropriately 100%. The concentration of sponge proteins in the hydrolysate is 1 to 30% by weight, and coloring is extremely light. The protein component of the hydrolysate is rich in amino acids such as glycine, aspartic acid, glutamic acid and arginine as shown in the results of the analysis in Table 1 below. A light colored sponge protein hydrolysate according to the present invention can be in the form of a liquid or a spray-dried powder and used in cosmetics, medicinal products and food products. Specifically, they are useful as hair care agents for the protection and treatment of damaged hair and as medicines for external application on skin, such as skin moisture-sustaining agents and anti-inflammatories and antiphlogistics, and are used as internal medicines such as health promoting agents, since they are effective in promoting the growth of human cells. The present invention will be explained by the following examples but not restricted to these examples. Example 1 Acidic water of pH 1 was prepared using electrolytic acidic water produced by a Suntron type MWH-1 and hydrochloric acid. One kg of crushed Spongia sponges were soaked in a 40-fold volume of acidic water and hydrolyzed at 90°C for 7 hours. A light colored material with almost no remaining residue was obtained. After cooling to room temperature, the resultant material was neutralized with a 40% sodium hydroxide solution and filtered. Then, ion-exchange resins (cation and anion mixed type) were added to the filtrate and the admixture was stirred for 2 hours for desalting. The ion-exchange resins were then removed by filtration to obtain a sponge extract solution having 15% by weight of the sponge hydrolysate. After adding 0.1% methylparaben and 10% ethanol as stabilizers, the sponge extract solution was stored at 4°C in a dark place. The sponge extract solution thus obtained was analyzed by an amino acid analyzer (LC-10AD System, a product of Shimadzu Corp.). Results are shown in Table 1. A molecular weight distribution for the sponge extract was determined using an Asahipak GS-320 column (column temperature: 40°C; detector: RI, UV 280 nm). An average molecular weight of 4,500 was obtained. Amino acid composition of the sponge extract solution (%) Hydroxyproline 8.13 Valine 1.71 Aspartic acid 4.44 Isoleucine 1.02 Threonine 1.98 Leucine 1.91 Serine 1.45 Tyrosine 0.14 Glutamic acid 5.69 Phenylalanine 0.57 Proline 4.09 Histidine 0.33 Glycine 58.66 Lysine 1.48 Alanine 4.34 Arginine 4.06 Example 2 The cell growth stimulating effect of the sponge extract solution obtained in Example 1 on human fibroblasts was measured. Cells used were human skin fibroblasts (NBTRGB Riken Cell Bank). Cells were cultured in an MEM medium (Cat. No. 6110-087 GIBCO BRL) supplemented with fetal bovine serum (FBS; Cat. No. 26140-79 GIBCO BRL) at 37°C under an atmosphere of 5% CO 2 . For the measurement, human skin fibroblasts were suspended in an MEM medium supplemented with 5% FBS, inoculated onto a 96-well microplate at a concentration of 5 x 10 5 cells/dish and incubated for 24 hours. Then, the medium was changed to a 0.5% MEM medium, and samples were added. Incubation was continued for 9 days and cells in the dishes were counted by a dye-exclusion method using trypan blue to obtain a cell survival rate. Results are shown in Table 2. It was revealed that the sponge extract solution obtained had an excellent cell growth stimulating effect. Cell growth stimulating effect of the sponge extract solution Amount of sponge extract solution added Cell survival rate (%) 2.5 122 5.0 157 10.0 174 Example 3 The effect of the sponge extract solution obtained in Example 1 on wrinkles on the outer corner of the eye (crow's feet) was measured. A 1% by weight sponge extract solution was prepared using purified water. A 1% by weight collagen hydrolysate solution was prepared for use as a control. To each test subject, the sponge extract was applied on the left outer corner of the eye and the collagen hydrolysate was applied on the right outer comer of the eye 2 times a day for 3 weeks. The image of wrinkles was photographed using a video microscope by lighting the skin at a 25-degree angle according to a replica method. Results of image processing analysis are shown in Table 3. It was revealed that the sponge extract solution was effective to reduce wrinkles. Example 4 The effect of the sponge extract solution obtained in Example 1 on the hair cuticle (cuticula pili) was studied. Sponge extract solution: a 1% by weight sponge extract solution was prepared using purified water. Control: a 10% ethanol solution containing 0.1% methylparaben was used as a control. Hydrolyzed collagen: a 1% hydrolyzed collagen was used as a reference. In each test, 10 cm hair strands were sampled and made into a bundle and briefly washed with water. Each sample solution was applied to the bundle and allowed to stick onto the hair, and then the bundle was treated with a bleaching agent containing 4% hydrogen peroxide, rinsed with warm water and dried. After the abovementioned treatment, the surface of the hair samples was observed by scanning electron microscopy. Figure 1 shows the effect of the control sample on the hair cuticle; it was observed that the cuticle was loosened and thus evidently damaged. Figure 2 shows the effect of the sponge extract solution of the present invention on the hair cuticle; no damage to the cuticle was observed, which confirmed that the sponge extract solution suppressed any damage caused by the bleaching agent. Figure 3 shows the effect of the reference sample, hydrolyzed collagen, on the hair cuticle; damage to the cuticle was observed. Figure 1 is a photograph showing the hair surface. If proteins extracted from sponges have a molecular weight of more than 5,000, their cell growth stimulating effect on skin or hair is low, and they have little therapeutic effect and low moisture-retaining effect, and thus cannot protect skin or hair. Therefore, it is important to reduce the molecular weight to less than 5,000, which conventionally requires complicated processes such as hydrolysis using proteases, and purification of an extract is laborious. According to the present invention, the problem of coloring of the hydrolysate is solved and a hydrolysate having a molecular weight of less than 5,000 can be obtained at high yield without using protein hydrolase. The light colored sponge. protein hydrolysate obtained in the present invention can be used as a raw material having a human cell growth stimulating effect in cosmetics, medicinal products or food products.

Claims: A sponge protein hydrolysate which is obtainable by a method wherein the hydrolysis is carried out using an acidic solution in which the pH is adjusted to 1 using electrolytic acidic water with a pH of less than 2.5 and an oxidation-reduction potential of more than 1,000 mV admixed with an acid to obtain sponge proteins having a molecular weight of less than 5,000, using sponge skeleton fibers (spongin fibers) refined from sponges as the raw material. A sponge protein hydrolysate as claimed in claim 1 wherein the sponge protein hydrolysate is a lightly colored solution having a concentration of 1 to 30% by weight. The use of a sponge protein hydrolysate as claimed in claim 1 or 2 as a raw material having a human cell growth stimulating-effect in cosmetics, medicinal products and food products. A method of producing a sponge protein hydrolysate wherein the hydrolysis is carried out using an acidic solution in which the pH is adjusted to 1 using electrolytic acidic water with a pH of less than 2.5 and an oxidation-reduction potential of more than 1,000 mV admixed with an acid to obtain sponge proteins having a molecular weight of less than 5,000, using sponge skeleton fibers (spongin fibers) refined from sponges as the raw material. A method of producing a sponge protein hydrolysate as claimed in claim 4 wherein the sponge protein hydrolysate is a lightly colored solution having a concentration of 1 to 30% by weight.

Inventors: NAKAMURA KENJI, NAKAMURA KOUJI, NAKAMURA, KENJI, NAKAMURA, KOUJI
Applicants: NAKAMURA KENJI, NAKAMURA KOUJI, NAKAMURA, KENJI, NAKAMURA, KOUJI
Application year: 2000
Main classification: C07K2
IPC codes: C12N5, A61K38, A23J3, A61P43, A61K8, C07K1, C12P21, A23L1, C07K14, C12R1, A61K35