JP7795692B2 - Bacteria suppressant, body odor suppressant, and axillary odor prevention and improvement agent - Google Patents

Description

The present invention relates to a body odor suppressant, an agent for preventing or ameliorating axillary malodor, and an agent for suppressing the bacterial count of bacteria that cause body odor, all of which contain erythritol as an active ingredient.

Body odor refers to the odor emanating from the body, and in the narrow sense, refers to unpleasant odors. Depending on the location of the odor, the quality of the odor, and the causative substance, body odor can be divided into underarm odor, foot odor, scalp odor, oily odor, acid odor, and body odor associated with aging. However, all of these are known to be caused in part by substances produced by microorganisms, such as resident skin bacteria, metabolizing bodily substances present on the surface of the body, such as sweat, sebum, and keratin.

Everyone has body odor, but there is a great need to prevent or suppress it. Furthermore, if the body odor is so strong that it causes discomfort to those around you or bothers the person, it may be considered a condition known as "axillary odour syndrome" and may be treated accordingly.

As a result, research and development is being conducted into technologies to suppress body odor. For example, Patent Document 1 describes how camphor tree extract or cinchona extract suppresses the production of diketone compounds (substances that cause sour and oily odors) by bacteria normally present on the skin. Furthermore, Patent Document 2 describes how propylene glycol fatty acid esters containing fatty acids with 8 to 14 carbon atoms as constituent fatty acids and with a monoester content of 90% by mass or more suppress the growth of bacteria that cause body odor. Furthermore, Patent Document 3 describes how the combined use of 1,2-hexanediol and/or 1,2-octanediol with α-bisabolol can suppress the growth of bacteria that cause body odor and prevent body odor.

Patent No. 6130472 Patent No. 6242636 Patent No. 5393962

However, even in light of the above patent documents, there are still not enough technologies available that effectively suppress body odor or that effectively reduce the number of bacteria that cause body odor. The present invention has been made to solve these problems, and aims to provide technologies that suppress body odor, prevent or improve axillary malodor, and reduce the number of bacteria that cause body odor.

As a result of extensive research, the inventors have discovered that erythritol significantly suppresses body odor and the number of bacteria that cause body odor. Based on this finding, they have completed the following inventions.

(1) The body odor suppressant of the present invention contains erythritol as an active ingredient.

(2) The agent for preventing and improving axillary odor according to the present invention is an agent for preventing or improving axillary odor, and contains erythritol as an active ingredient.

(3) The bacterial count inhibitor of the present invention is an agent for suppressing the number of bacteria that cause body odor, and contains erythritol as an active ingredient.

(4) In the present invention, the body odor-causing bacteria may be bacteria of the genus Corynebacterium, Staphylococcus, or Micrococcus.

According to the present invention, body odor can be suppressed. Furthermore, according to the present invention, the symptoms of axillary malodor can be improved or axillary malodor can be prevented. Furthermore, according to the present invention, the number of bacteria that cause body odor can be suppressed.

Furthermore, erythritol, the active ingredient of the present invention, is an extremely safe substance for humans and animals, as evidenced by its use as a food product. Therefore, according to the present invention, it is possible to suppress body odor, prevent or improve axillary malodor, or suppress the number of bacteria that cause body odor, without any concerns about skin irritation or safety.

This is a bar graph showing the turbidity of the culture medium obtained by culturing body odor-causing bacteria (strains 1 to 4) using a medium containing no sugar alcohol (control) and media containing various sugar alcohols (Ery medium, Man medium, Sol medium). 1 is a line graph showing the turbidity of culture solutions obtained by culturing bacteria causing body odor using media containing various concentrations of erythritol (Ery medium) or sorbitol (Sol medium). 1 is a bar graph showing the turbidity of culture solutions obtained by culturing body odor-causing bacteria (strains 3 and 4) using media containing erythritol at various concentrations. (A) is a bar graph showing the turbidity of the culture medium obtained by culturing body odor-causing bacteria using a medium containing no erythritol (erythritol concentration: 0%) and a medium containing erythritol (erythritol concentration: 20%). (B) is a bar graph showing the axillary odor intensity of the culture medium.

The present invention is described in detail below.

Erythritol is a monosaccharide alcohol with the chemical name 1,2,3,4-butaneterol and is also called erythritol. Erythritol may be commercially available or may be produced according to methods known to those skilled in the art.

A well-known production method involves culturing erythritol-producing bacteria using glucose or other carbon sources, producing erythritol, and then purifying the product. Examples of erythritol-producing bacteria include microorganisms belonging to the genera Trigonopsis or Candida (Japanese Patent Publication No. 47-41549), Torulopsis, Hansenula, Pichia, or Debaryomyces (Japanese Patent Publication No. 51-21072), Moniliella (Japanese Patent Publication Nos. 60-110295 and 10-215887), Aureobasidium (Japanese Patent Publication No. 63-9831), and Yellovia (Japanese Patent Publication No. 10-215887). Culture conditions may be standardized to suit each type of bacteria. Erythritol can be purified by conventional methods, including cell separation, chromatographic isolation of erythritol, desalting, decolorization, crystallization, crystal decomposition, and drying.

As mentioned above, "body odor" refers to the odor emanating from the body. Depending on the source, body odor can be divided into categories such as armpit odor, foot odor, scalp odor, and hair odor. Furthermore, depending on the type of odor, it can also be divided into sweat odor, oily odor, acid odor, oxidized odor, and body odor associated with aging. Known components of body odor include aldehydes (scalp odor, hair odor), steroids such as androstenone (male body odor), fatty acids such as acetic acid and propionic acid (scalp odor, hair odor), isovaleric acid (3-methylbutanoic acid, sole of the foot odor), isovaleric aldehyde (foot odor), diacetyl, 2-nonenal (body odor associated with aging), 3-methyl-2-hexenoic acid (armpit odor), vinyl ketones (a pungent, oxidized odor), 3-hydroxy-3-methylhexanoic acid (spicy odor), and 3-methyl-3-sulfanylhexan-1-ol (sulfur odor).

"Suppressing body odor" means reducing body odor or making the intensity of body odor less. Body odor intensity can be confirmed by detecting the concentration of specific components of body odor using commercially available measuring equipment (gas chromatograph-mass spectrometer (GC-MS), odor sensors using metal oxide semiconductors, etc.). It can also be confirmed using a sensory test that uses the human sense of smell to determine odor intensity.

"Axillary malodor" refers to a condition in which an unpleasant odor emanates from the armpits (the hollows under the arms). In this invention, "improving axillary malodor" means reducing the odor emanating from the armpits (axillary odor) or lessening the intensity of the odor. Furthermore, "preventing axillary malodor" means reducing the odor to the point where no treatment or other measures are necessary.

"Body odor-causing bacteria" refers to microorganisms that reside on the body surface and metabolize substances that cause body odor (examples of which include the "constituents of body odor" mentioned above). Specific examples of body odor-causing bacteria include Corynebacterium bacteria such as C. minutissimum, C. xerosis, C. tenuis, and C. striatum; Staphylococcus bacteria such as S. aureus, S. epidermidis, S. warneri A, S. warneri B, S. caprae B, S. haemolyticus, S. capitis A, S. capitis B, S. lentus, S. gallinarum, S. delphini, S. hominis, S. xylosus, S. hyicus, and S. cohnii; and Micrococcus bacteria such as M. luteus.

In the present invention, "bacterial count" means the number of microorganisms.

Whether or not the number of bacteria that cause body odor has been suppressed can be determined by a culture test, as shown in the examples described below. That is, two identical media are prepared, one with the addition of a test substance (bacterial count inhibitor) and the other without. The body odor-causing bacteria are inoculated into both media and cultured for a predetermined period, after which the bacterial count in the media is measured. The bacterial count can be measured simply by the turbidity method, but known methods such as the dry bacterial weight method, wet bacterial weight method, or real-time PCR method can also be selected as appropriate depending on the medium, culture conditions, and type of bacteria being measured. If the result shows that the bacterial count is lower in the sample with the test substance (bacterial count inhibitor) added than in the sample without it, it can be determined that the test substance (bacterial count inhibitor) has suppressed the bacterial count of the body odor-causing bacteria.

The agent of the present invention can be suitably used in cosmetics, quasi-drugs, pharmaceuticals, and hygiene products such as cleansers and sanitary napkins intended for use on body surfaces such as the armpits, hands, feet, back, and head. Products incorporating the agent of the present invention can be produced by adding erythritol to ingredients typically used in such products (e.g., oils, surfactants, alcohols, preservatives, chelating agents, antioxidants, thickeners, fragrances, disinfectants, and other ingredients). The erythritol content can be appropriately set depending on the product form and intended use, but can be, for example, 0.01 to 35% by weight, preferably 0.01 to 30% by weight, more preferably 0.5 to 25% by weight, and even more preferably 1 to 20% by weight. Product formulations include aerosols, roll-ons, sticks, creams, sheets, lotions, emulsions, gels, and powders.

The present invention will be described below based on various examples. Note that the technical scope of the present invention is not limited to the features demonstrated in these examples.

<Test Method>
(1) Sugar Alcohol In this example, commercially available sugar alcohols were used: erythritol (product name: Erythritol, white granules), D-sorbitol (product name: Sorbitol FP, white granules), and D-mannitol (product name: Mannitol, white granules) (all manufactured by Bussan Food Science Co., Ltd.).

(2) Bacterial Strains In this example, strains Nos. 1 to 4 listed in Table 1 were used. Strain No. 1 is described in Patent Document 4 (JP 2015-120677 A) as a bacterium causing axillary odor, and in Patent Document 5 (JP 2017-43568 A) as a bacterium causing foot odor. Strain No. 2 is described in Patent Document 4 as a bacterium causing axillary odor. Strain No. 3 is described in Patent Document 5 as a bacterium causing foot odor. Strain No. 4 was collected from the soles of the odor-producing feet of a male elementary school student. The strains were collected by placing the soles of the feet of a male elementary school student on LB agar medium and then culturing the LB agar medium at 30°C.

(3) Culture Media In this example, the following culture media were used. All reagents were obtained from Fujifilm Wako Pure Chemical Industries, Ltd.
LB liquid medium (hypopolypeptone: 1 (w/v)%, yeast extract: 0.5 (w/v)%, sodium chloride: 1 (w/v)%)
LB agar medium (hypopolypeptone: 1 (w/v)%, yeast extract: 0.5 (w/v)%, sodium chloride: 1 (w/v)%, agar: 1.5 (w/v)%)
802 medium (hypopolypeptone: 1 (w/v)%, yeast extract: 0.2 (w/v)%, magnesium sulfate heptahydrate: 0.1 (w/v)%, pH 7.0)
Ery medium (802 medium containing 4-20% (w/v) erythritol)
Man medium (802 medium containing 10% (w/v) D-mannitol)
Sol medium (802 medium containing 7-26% (w/v) D-sorbitol)

Example 1: Sugar Alcohol Study Strains 1 to 4 were plated on LB agar medium and statically cultured at 30°C for 3 days. Subsequently, each strain was inoculated into 2 mL of LB liquid medium and cultured with shaking at 30°C and 210 revolutions per minute (rpm) for 20 hours (preculture). 0.8 mL each of Ery medium, Man medium, and Sol medium, each containing 10% (w/v) of sugar alcohol, was dispensed into a 96-well deep-well plate (AxyGen Scientific, Inc., CA, USA). As a control, 802 medium containing no sugar alcohol was similarly dispensed into a 96-well deep-well plate. Each pre-culture medium (25 μL each for No. 1 and No. 2, 50 μL for No. 3, and 20 μL for No. 4) was inoculated into the wells, and the mixture was shaken (main culture) at 30°C for 23 hours using an MBR-034P shaker (Taitec, Tokyo, Japan).

The bacterial cell concentration of the culture medium from the main culture was measured by the turbidity method. Specifically, 180 μL of water was dispensed into a 96-well flat-bottom plate (4845-96F, Watson). 20 μL of the culture medium from the main culture was added to the well, and the turbidity (OD ₆₆₀ ) was measured by detecting the transmitted light intensity at a wavelength of 660 nm using a microplate reader (SpectraMax® M2, Molecular Devices). Furthermore, the turbidity when the control medium was used was set to 100, and the turbidity when the sugar alcohol-containing medium was used was expressed as a percentage, which was called the relative turbidity (%). The results are shown in Figure 1.

As shown in Figure 1, for all strains 1 to 4, the turbidity of the culture solution was lowest when Ery medium was used. In other words, when a medium containing erythritol was used, the bacterial cell concentration was significantly lower than when other media (medium without sugar alcohols, medium containing D-mannitol, medium containing D-sorbitol) were used. These results demonstrate that erythritol can suppress the number of bacteria that cause body odor.

Example 2: Concentration Study (1) Strain No. 1 Strain No. 1 was cultured using the method described in Example 1, and the turbidity (OD ₆₆₀ ) of the culture medium was measured. For the main culture, 2 mL of the pre-culture medium was placed in a CELLreactor® filter-cap centrifuge tube (Greiner Bio-One) and cultured with shaking at 30°C and 210 revolutions per minute (rpm) for 24 hours using a BioShaker BR-23FP (TAITEC). Ery and Sol media with sugar alcohol concentrations of 5, 10, 15, and 20% (w/v) were used. The turbidity of the culture medium containing sugar alcohol was expressed as relative turbidity (%), with the turbidity of the control medium set at 100. The results are shown in Figure 2.

As shown in Figure 2, the turbidity of Ery medium was lower than that of the control and Sol medium at all sugar alcohol concentrations. In other words, when a medium containing erythritol was used, the bacterial cell concentration was significantly lower than when other media (medium containing no sugar alcohol, medium containing the same concentration of D-sorbitol) were used, regardless of the erythritol concentration. These results demonstrate that erythritol can effectively suppress the number of bacteria that cause body odor, regardless of the concentration.

(2) Strains No. 3 and No. 4 Strains No. 3 and No. 4 were cultured by the method described in Example 1, and the turbidity (OD ₆₆₀ ) was measured. However, the main culture media used were Ery media with erythritol concentrations of 6.7, 10, 15, and 20 (w/v)% and 802 medium (control) containing no sugar alcohol. The turbidity of the culture solution using Ery medium was expressed as relative turbidity (%), with the turbidity when the control medium was used being set at 100. The results are shown in Figure 3.

As shown in Figure 3, the relative turbidity was significantly lower than 100% at erythritol concentrations of 6.7, 10, 15, and 20% (w/v). In other words, when a medium containing erythritol was used, the bacterial cell concentration was significantly lower than when a medium containing no sugar alcohol was used, regardless of the erythritol concentration. These results demonstrate that erythritol can effectively suppress the number of bacteria that cause body odor, regardless of the concentration.

Example 3: Examination of odor suppression effect Patent Document 6 (JP 2003-24422 A, [0002], etc.) and Patent Document 7 (JP 2009-508478 A, [0003], etc.) describe that isovaleric acid is thought to be the main causative substance of foot odor, and that isovaleric acid may be produced by the enzymatic conversion of L-leucine. Therefore, body odor-causing bacteria were cultured in a medium containing L-leucine, and the odor suppression effect of erythritol was examined.

Specifically, strain No. 1 was cultured using the method described in Example 1. However, the 802 medium used was supplemented with 0.5 mg/mL leucine and 0.2 (w/v)% glucose. The main culture medium used was Ery medium (erythritol concentration 20 (w/v)%) and 802 medium containing no sugar alcohol (erythritol concentration 0%). The main culture was performed for 24 hours. The turbidity (OD ₆₆₀ ) of the main culture medium was measured using the method described in Example 1. The odor intensity was measured using the axillary odor measurement mode of the Kunkun Body (registered trademark) (Konica Minolta, Inc.). This axillary odor measurement mode detects the concentrations of isovaleric acid and ammonia to measure the intensity of axillary odor. The results are shown in Figure 4.

As shown in Figure 4, the turbidity of the culture medium was significantly lower when the erythritol concentration in the medium was 20% (w/v) compared to 0%. The intensity of the axillary odor was also significantly lower when the erythritol concentration was 20% (w/v) compared to 0%. In other words, when a medium containing erythritol was used, the bacterial cell concentration in the culture medium was significantly lower, and the intensity of the axillary odor was also significantly lower, compared to when a medium not containing erythritol was used. These results demonstrate that erythritol can suppress the number of bacteria that cause body odor, as well as suppress body odor itself.

Claims (7)

An agent for suppressing the number of bacteria that cause body odor selected from bacteria of the genus Corynebacterium and bacteria of the genus Micrococcus , comprising erythritol as an active ingredient for suppressing the number of bacteria that cause body odor selected from bacteria of the genus Corynebacterium and bacteria of the genus Micrococcus. The agent according to claim 1, which is a body odor suppressant. The agent according to claim 1, which is an agent for preventing or ameliorating axillary odour. A cosmetic for suppressing the number of bacteria that cause body odor selected from bacteria of the genus Corynebacterium and bacteria of the genus Micrococcus, comprising erythritol as an active ingredient for suppressing the number of bacteria that cause body odor selected from bacteria of the genus Corynebacterium and bacteria of the genus Micrococcus . A quasi-drug for suppressing the number of bacteria that cause body odor selected from bacteria of the genus Corynebacterium and bacteria of the genus Micrococcus, comprising erythritol as an active ingredient for suppressing the number of bacteria that cause body odor selected from bacteria of the genus Corynebacterium and bacteria of the genus Micrococcus . A pharmaceutical for suppressing the number of bacteria that cause body odor selected from bacteria of the genus Corynebacterium and bacteria of the genus Micrococcus, comprising erythritol as an active ingredient for suppressing the number of bacteria that cause body odor selected from bacteria of the genus Corynebacterium and bacteria of the genus Micrococcus. A sanitary product for suppressing the number of bacteria that cause body odor selected from bacteria of the genus Corynebacterium and bacteria of the genus Micrococcus, comprising erythritol as an active ingredient for suppressing the number of bacteria that cause body odor selected from bacteria of the genus Corynebacterium and bacteria of the genus Micrococcus .