JP2013043851A - Antioxidation stress enzyme expression inducing agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new application of L-carbocisteine.SOLUTION: The antioxidation stress enzyme expression inducing agent includes L-carbocisteine or its pharmaceutically acceptable salt as an active constituent.

Description

  The present invention relates to an antioxidant stress enzyme expression inducer and an Nrf2 activator.

  L-carbocysteine is an abscess in diseases such as upper respiratory tract inflammation (pharyngitis, laryngitis), acute bronchitis, bronchial asthma, chronic bronchitis, bronchiectasis, pulmonary tuberculosis, and chronic sinusitis. It has an action and is widely used clinically as a highly safe expectorant.

  Furthermore, a therapeutic and prophylactic agent for influenza virus infection (Patent Document 1) and a therapeutic and prophylactic agent for rhinovirus infection (Patent Document 2) containing L-carbocysteine as an active ingredient are known.

JP 2005-281227 A JP 2005-281229 A

  An object of the present invention is to provide a novel use of L-carbocysteine.

  The present inventors have an effect that L-carbocysteine promotes nuclear translocation of the transcription factor Nrf2 (NF-E2 related factor 2), and has an effect of expressing an antioxidant stress enzyme through this effect. And gained completely new knowledge. The present invention is based on this novel finding.

  That is, the present invention provides an antioxidant stress enzyme expression inducer containing L-carbocysteine or a pharmaceutically acceptable salt thereof as an active ingredient.

  When a normally balanced redox state in a living body is excessively inclined in the direction of oxidation, or an electrophilic substance becomes excessive, various diseases are caused. According to the antioxidant stress enzyme expression inducer, L-carbocysteine or a pharmaceutically acceptable salt thereof is used as an active ingredient, so that the antioxidant stress enzyme can be expressed. And the state etc. which inclined excessively to the oxidation direction through this effect | action can be prevented, or can be recovered | restored from these states.

  In the present specification, the “antioxidant stress enzyme” means an enzyme encoded by a gene whose expression is regulated at the transcription level by the transcription factor Nrf2.

  The present invention also provides an antioxidant stress enzyme expression promoter comprising L-carbocysteine or a pharmaceutically acceptable salt thereof as an active ingredient.

  The present invention further includes an Nrf2 activator comprising L-carbocysteine or a pharmaceutically acceptable salt thereof as an active ingredient, and an Nrf2 nucleus comprising L-carbocysteine or a pharmaceutically acceptable salt thereof as an active ingredient. Provide migration promoter.

  As an action of L-carbocysteine or a pharmaceutically acceptable salt thereof, an action to improve the physical properties of sputum and expedite discharge, an action to promote repair of pilus and improve transport ability, and a first step of bacterial infection The action etc. which suppress adhesion to a pharyngeal epithelial cell of a certain bacterium are known. However, L-carbocysteine or a pharmaceutically acceptable salt thereof has never been known to have an action of promoting the nuclear translocation of the transcription factor Nrf2 and the action of antioxidative stress enzyme via this. unknown.

  According to the present invention, novel action of L-carbocysteine or a pharmaceutically acceptable salt thereof based on the action of promoting the nuclear translocation of the transcription factor Nrf2 and the action on the expression of the antioxidant stress enzyme mediated thereby. Applications (antioxidant stress enzyme expression inducer, antioxidant stress enzyme expression promoter, Nrf2 activator, Nrf2 nuclear translocation promoter) can be provided.

FIG. 3 is a diagram showing the results of Western blot analysis of Example 1. 4 is a graph showing the results of gene expression level analysis in Example 2. 6 is a graph showing the results of gene expression level analysis in Example 3.

  Hereinafter, although the form for implementing this invention is demonstrated in detail, this invention is not limited to these.

The antioxidant stress enzyme expression inducer of the present invention contains L-carbocysteine represented by the following chemical formula (1) or a pharmaceutically acceptable salt thereof as an active ingredient.

  Since the antioxidant stress enzyme expression inducer contains L-carbocysteine or a pharmaceutically acceptable salt thereof as an active ingredient, it can induce the expression of antioxidant stress enzyme. Here, “expression induction” includes expressing an antioxidant stress enzyme that is not expressed, and increasing the expression level of the expressed antioxidant stress enzyme.

  L-carbocysteine is a compound that is also called by the chemical name S- (carboxymethyl) -L-cysteine (S- (carboxymethyl) -L-cysteine). In the present specification, L-carbocysteine is also referred to as “S-CMC”.

  A pharmaceutically acceptable salt of L-carbocysteine means a salt of L-carbocysteine with a pharmaceutically acceptable base (eg, inorganic or organic base) or acid (eg, inorganic or organic acid). .

  Examples of salts with pharmaceutically acceptable inorganic bases include inorganic bases such as aluminum, ammonium, calcium, copper, ferrous, ferric, lithium, magnesium, manganese, manganite, potassium, and sodium. Of the salt.

  Examples of salts with pharmaceutically acceptable organic bases include arginine, betaine, caffeine, choline, N, N′-dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, Ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resin, procaine, purine, theobromine, triethylamine, trimethylamine, tripropyl Examples thereof include salts with organic bases such as amines and tromethamine.

  Examples of salts with pharmaceutically acceptable inorganic acids include salts with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid.

  Examples of salts with pharmaceutically acceptable organic acids include acetic acid, maleic acid, fumaric acid, succinic acid, lactic acid, malic acid, tartaric acid, citric acid, methanesulfonic acid, p-toluenesulfonic acid, salicylic acid, stearin. And salts with organic acids such as acids and palmitic acid.

  As will be described in detail in the Examples, L-carbocysteine has an action of promoting the transfer of the transcription factor Nrf2 into the nucleus and inducing the expression of the antioxidant stress enzyme through this. It is known that the transcription factor Nrf2 is normally bound to a factor called Keap1 in the cytoplasm and is inhibited from entering the nucleus. It is known that when a cell is exposed to oxidative stress or an electrophilic substance, or due to phosphorylation of the transcription factor Nrf2, the transcription factor Nrf2 dissociates from Keap1 and moves into the nucleus. In addition, the transcription factor Nrf2 transferred into the nucleus binds to an antioxidant response element ARE (antioxidant response element) or an electrophilic substance response element EpRE (electrophile response element), and is a gene whose expression is regulated by these sequences. It is known to induce the expression of E. coli (for example, Biochemistry, Vol. 81, No. 6, pp. 447-455, 2009).

  Therefore, in the present specification, the term “antioxidant stress enzyme” means an enzyme encoded by a gene whose expression is regulated at the transcription level by the transcription factor Nrf2, and preferably an antioxidant response element ARE (antioxidant response element). ) Or an electrophile responsive element EpRE (electrophilic response element) encoded by a gene whose expression is regulated at the transcriptional level.

  Antioxidant stress enzymes include enzymes that function to maintain homeostasis against stress. Specific examples thereof include heme oxygenase 1 (HO-1), glutathione synthetase, thioredoxin reductase, thioredoxin, peroxyred Antioxidant enzymes such as xin 1, glutathione peroxidase and glutamate cysteine ligase, detoxification enzymes such as glutathione-S-transferase (GST), quinone oxidoreductase (NQO1), epoxide hydrase and aldoketreductase Phase detoxification enzyme), cystine transporter, multi-drug resistance associated protein 1 (multi-drug resistance associated protein 1), multi-drug resistance-related protein 2 (multi-drug re- Examples thereof include drug transporters such as sistance associated protein 2) and ubiquitin proteosomes such as 20S proteasome subunit β5 (20S proteasome subunit β5).

  The antioxidant stress enzyme expression inducer may further contain an antioxidant as another active ingredient. Any antioxidant can be used without particular limitation as long as it is pharmaceutically acceptable. Examples of the antioxidant include ascorbic acid, α-tocopherol, tocotrienol, polyphenol (flavonoid, resveratrol, etc.), carotenoid, and N-acetyl-L-cysteine.

  The antioxidant stress enzyme expression inducer may further contain a pharmaceutically acceptable additive. Examples of additives include excipients, lubricants, binders, disintegrants, stabilizers, flavoring agents, and diluents. These additives are not particularly limited as long as they can be used for the production of pharmaceutical preparations, and are described, for example, in the Pharmaceutical Additives Dictionary [Japan Pharmaceutical Additives Association, Yakuji Nippo (2007)]. Can be used as appropriate.

  The excipient may be either an organic excipient or an inorganic excipient. Examples of the organic excipient include sugar derivatives such as lactose, sucrose, sucrose, mannitol, sorbitol; starch derivatives such as corn starch, potato starch, α starch, dextrin; cellulose derivatives such as crystalline cellulose; gum arabic; dextran A pullulan. Examples of the inorganic excipient include silicate derivatives such as light inorganic silicic acid, synthetic aluminum silicate, calcium silicate, and magnesium aluminate metasilicate; phosphates such as calcium hydrogen phosphate; calcium carbonate and the like Carbonate; Sulfates such as calcium sulfate are listed.

  Examples of lubricants include stearic acid metal salts such as stearic acid, calcium stearate, magnesium stearate; talc; colloidal silica; waxes such as bee gum; adipic acid; sulfates such as sodium sulfate; glycol; fumaric acid; DL-leucine; fatty acid sodium; lauryl sulfates such as sodium lauryl sulfate and magnesium lauryl sulfate; silicic acids such as anhydrous silicic acid and silicic acid hydrate.

  Examples of the binder include hydroxypropyl cellulose, hydroxymethylpropyl cellulose, polyvinyl pyrrolidone, and macrogol.

  Examples of disintegrants include cellulose derivatives such as low-substituted hydroxypropyl cellulose, carboxymethyl cellulose, carboxymethyl cellulose calcium, and internally crosslinked sodium carboxymethyl cellulose; chemically modified starch such as carboxymethyl starch, sodium carboxymethyl starch, and crosslinked polyvinylpyrrolidone. -Cellulose is mentioned.

  Examples of the stabilizer include parahydroxybenzoates such as methyl paraben and propyl paraben; alcohols such as chlorobutanol, benzyl alcohol, and phenethyl alcohol; benzalkonium chloride; cresols such as phenol and cresol; thimerosal; dehydroacetic acid Sorbic acid.

  Examples of the flavoring agent include sweeteners, acidulants, and fragrances.

  Examples of the diluent include distilled water for injection, physiological saline, and glucose injection.

  The antioxidant stress enzyme expression inducer is one type selected from the group consisting of L-carbocysteine or a pharmaceutically acceptable salt thereof alone or, if necessary, the antioxidant and the additive. It can be prepared by mixing with the above.

  The antioxidative stress enzyme expression inducer can be administered to humans by applying conventional pharmacologically well-known forms and administration routes, such as powders, tablets, capsules, fine granules, granules, It can be administered orally as a preparation such as a syrup, or parenterally as a preparation such as an ointment, cream, lotion, gel, or patch.

  Administration of the antioxidant stress enzyme expression inducer varies depending on, for example, age, body weight, symptoms, etc., but in oral administration, 500 to 5000 mg is administered once, more preferably 1000 to 3000 mg is administered 3 times a day. It is desirable.

  The antioxidant stress enzyme expression inducer is effective for prevention or treatment of diseases that develop due to oxidative stress. Examples of such diseases include coronary heart disease, myocardial infarction, Huntington's disease, liver fibrosis, pulmonary fibrosis, cancer, and cataract.

  As explained in detail in the Examples, L-carbocysteine induces antioxidant stress enzyme expression more strongly when cells are under oxidative stress than when they are under non-oxidative stress. Has an effect. That is, it has an effect of further promoting the expression of an antioxidant stress enzyme induced by oxidative stress. Therefore, L-carbocysteine or a pharmaceutically acceptable salt thereof can also be used as an antioxidant stress enzyme expression promoter.

  The antioxidant stress enzyme expression promoter of the present invention contains L-carbocysteine or a pharmaceutically acceptable salt thereof as an active ingredient. In addition, components (antioxidants, additives, etc.) that can be further added to the antioxidant stress enzyme expression promoter, dosage form, usage, dosage, application, etc. are the same as those described for the antioxidant stress enzyme expression inducer. Can be.

  L-carbocysteine or a pharmaceutically acceptable salt thereof promotes dissociation (activation) of the binding between transcription factor Nrf2 and Keap1, thereby promoting the transfer of transcription factor Nrf2 into the nucleus it is conceivable that. Therefore, L-carbocysteine or a pharmaceutically acceptable salt thereof can be used as an Nrf2 activator. Furthermore, L-carbocysteine or a pharmaceutically acceptable salt thereof can also be used as an Nrf2 nuclear translocation promoter.

  The Nrf2 activator and Nrf2 nuclear translocation promoter of the present invention contain L-carbocysteine or a pharmaceutically acceptable salt thereof as an active ingredient. In addition, components (antioxidants, additives, etc.) that can be further added to the Nrf2 activator and Nrf2 nuclear translocation promoter, dosage form, usage, dosage, application, etc., are related to the antioxidant stress enzyme expression inducer. It can be the same as described.

  Hereinafter, the present invention will be described in more detail based on examples.

[Example 1: Promotion of Nrf2 translocation into the nucleus]
The example which analyzed the change of the nuclear Nrf2 protein amount by administration of L-carbocysteine is shown. In the following examples, alveolar macrophages collected from C57BL / 6 mice (male) (also referred to as “Nrf2 + / +”) and mice knocked out by the transcription factor Nrf2 (also referred to as “Nrf2 − / −”) are used. The alveolar macrophages collected from the above are used.

[Collecting alveolar macrophages]
The mouse was euthanized by carbon dioxide treatment, a cannula was inserted into the trachea of the mouse, and bronchoalveolar lavage fluid was collected with 1 mL of physiological saline. This was repeated 5 times, and the pooled bronchoalveolar lavage fluid was centrifuged (200 × g, 5 minutes, 4 ° C.) to precipitate the collected cells. After removing the supernatant and resuspending in RPMI 1640 medium (10% FBS), the cells were seeded in a 10 cm dish.

[Preparation of aqueous L-carbocysteine solution]
2 mL of 1 mol / L sodium hydroxide aqueous solution was added to 35.84 mg of L-carbocysteine (Nippon Rikagaku, Lot .: 41AL206) and completely dissolved. After adding RPMI1640 medium (10% FBS), 1 mol / L hydrochloric acid was added to adjust the pH to 7.2 to 7.4 to a final volume of 20 mL (10 mmol / L aqueous solution). Serial dilution was performed from 10 mmol / L aqueous solution with RPMI 1640 medium (10% FBS) to prepare 0.3, 1, 3 mmol / L aqueous solutions, respectively. The L-carbocysteine aqueous solution was prepared as a task.

[Treatment with aqueous L-carbocysteine solution and extraction of protein in the nucleus]
The cells obtained in the above [Collecting alveolar macrophages] were left overnight in an incubator (5% CO ₂ , 37 ° C.) and washed with RPMI 1640 medium (10% FBS). Thereafter, L-carbocysteine solution (0.3, 1, 3, 10 mM) was added. Cells were washed with cold phosphate buffered saline (PBS (−)) 6 or 24 hours after L-carbocysteine treatment, and using a nuclear extraction kit (Panomics, Redwood City, Calif.) According to the instruction manual, the cell nucleus Inner protein was extracted. The protein concentration was measured using Dc Protein Assay Kit (Bio-Rad Laboratories, Hercules, CA).

[Western blot analysis]
10-20 g of protein was separated by sodium dodecyl sulfate (SDS) -polyacrylamide gel electrophoresis using a 5-20% gradient gel, and then transferred to a polyvinylidene difluoride (PVDF) membrane (transfer) )did. The obtained membrane was shaken in a 3% skim milk suspension for 1 hour and washed with Tris-buffered saline (TBS) (containing 0.1% Tween 20) (TBS-T) (5 minutes × 3 times). The membrane was shaken overnight at 4 ° C. using anti-Nrf2 rabbit polyclonal antibody (Santa Cruz Biotechnology, Santa Cruz, Calif.) As the primary antibody. After washing with TBS-T (rinse x 3 times, 2 minutes x 2 times, 15 minutes x 1 time, 5 minutes x 1 time), secondary antibody solution (Peroxidase-conjugated Affini Pure Goat Anti-Mouse IgG (H + L) (Jackson) (ImmunoResearch Laboratories, West Grove, PA)) for 1 hour. Wash again with TBS-T (rinse x 3, 2 min x 2, 15 min x 1, 5 min x 1) and chemiluminescence (ECL, GE Healthcare, Buckinghamshire, England) to X-ray film A band was detected. In addition, Lamin B was adopted as an internal standard and reprobed with the same membrane.

  The results of Western blot analysis are shown in FIG. Addition of L-carbocysteine (S-CMC) increased the amount of nuclear Nrf2 protein in a dose-dependent manner (see the results of FIG. 1 “Nrf2 + / +”). In Nrf2 knockout mice, no protein was detected (see the result of “Nrf2 − / −” in FIG. 1). The results of Western blot analysis showed that L-carbocysteine has an action of activating Nrf2 and promoting Nrf2 nuclear translocation.

[Example 2: Induction of antioxidant stress enzyme expression]
The example which analyzed the expression level change of the antioxidant stress enzyme (GCLC, HO-1, GCLM, NQO1) by administration of L-carbocysteine is shown. “GCLC” refers to “catalytic subunit of glutamate cysteine ligase”, and “GCLM” refers to “modified subunit of glutamate cysteine ligase”.

[Collecting alveolar macrophages]
Alveolar macrophages were collected by the same method as in Example 1. The collected cells were resuspended in RPMI 1640 medium (10% FBS), and the cells were seeded in a 24-well plate.

[Preparation of aqueous L-carbocysteine solution]
An L-carbocysteine aqueous solution was prepared in the same manner as in Example 1.

[Treatment with L-carbocysteine aqueous solution and total RNA extraction]
The cells obtained in the above [Collecting alveolar macrophages] are allowed to stand overnight in an incubator (5% CO ₂ , 37 ° C.), washed with RPMI 1640 medium (10% FBS), and then an L-carbocysteine solution (0 .3, 1, 3, 10 mM) was added. 24 hours after the treatment with L-carbocysteine, the cells were washed with cold PBS (−), and total RNA was extracted using RNeasy Mini Kit (QIAGEN) according to the instruction manual. The concentration of total RNA was calculated by measuring absorbance.

[Analysis of mRNA amount by reverse transcription reaction and real-time PCR]
The extracted total RNA was subjected to a reverse transcription reaction using High capacity cDNA reverse transcription (Applied Biosystems, Foster City, Calif.). Thereafter, real-time PCR was performed by sequence detector (ABI7700, Applied Biosystems) using THUNDERBIRD qPCR Mix (Toyobo, Tokyo) and various primers. The results were analyzed by relative quantification using the comparative Ct method. PCR reaction conditions and primer sequences used are shown in Tables 1 and 2 below. Further, glutaraldehyde dehydrogenase (GAPDH) was employed as an endogenous control gene.

  The result of expression level analysis is shown in FIG. 2 (A) to 2 (D) show relative expression levels (relative to the expression level in mice (Nrf2 + / +) in the L-carbocysteine (S-CMC) non-added group being 1). Expression level) values are shown. In any antioxidant stress enzyme (GCLC, HO-1, GCLM, NQO1), the expression level increased in a dose-dependent manner by the addition of L-carbocysteine (FIGS. 2 (A) to (D) “ Nrf2 + / + "). On the other hand, no significant change in the expression level was observed in Nrf2 knockout mice regardless of the presence or absence of L-carbocysteine addition (FIGS. 2 (A) to (D) “Nrf2 − / −”).

  2 (A) to 2 (D), “NAC” indicates the result when a 10 mM N-acetyl-L-cysteine (NAC) aqueous solution is added instead of the L-carbocysteine aqueous solution. With the addition of NAC, no increase in the expression level was observed in any of the antioxidant stress enzymes (FIGS. 2 (A) to (D)).

  From the results of FIG. 1 and FIGS. 2 (A) to (D), it was shown that L-carbocysteine induces the expression of antioxidant stress enzyme through the promotion of nuclear translocation of transcription factor Nrf2.

  NAC is also known as an antioxidant and has a chemical structure similar to that of L-carbocysteine. Since NAC did not have an anti-oxidative stress enzyme expression-inducing action, the action of promoting transcription of the transcription factor Nrf2 into the nucleus and the anti-oxidative stress enzyme expression-inducing action were extremely surprising unique to L-carbocysteine. It is an effect.

[Example 3: Expression induction of antioxidant stress enzyme under oxidative stress]
The example which analyzed the expression level change of the antioxidant stress enzyme (HO-1, GCLM) by administration of L-carbocysteine under the oxidative stress by a tobacco smoke extract (CSE) is shown.

[Collecting alveolar macrophages]
Alveolar macrophages were collected by the same method as in Example 1. The collected cells were resuspended in RPMI 1640 medium (10% FBS), and the cells were seeded in a 24-well plate.

[Preparation of aqueous L-carbocysteine solution]
An L-carbocysteine aqueous solution was prepared in the same manner as in Example 1.

[Preparation of tobacco smoke extract (CSE)]
Tobacco smoke (hi-lite, Nippon Tobacco Inc.) is sucked with a 50 mL syringe at a rate of 50 mL / 10 seconds and then bubbled into 10 mL of RPMI 1640 medium (FBS (−)) at a rate of 50 mL / 15 seconds. The operation was performed. This bubbling operation was performed 10 times per cigarette. The obtained tobacco smoke extract was adjusted to pH 7.2-7.5 using an aqueous sodium hydroxide solution and sterilized with a filter (pore size: 0.2 μm). This was designated as 100% cigarette smoke extract (CSE).

[Treatment with L-carbocysteine aqueous solution and total RNA extraction]
In the same manner as in Example 2, treatment with an aqueous L-carbocysteine solution and total RNA extraction were performed.

[Analysis of mRNA amount by reverse transcription reaction and real-time PCR]
The amount of mRNA was analyzed by the same method as in Example 2.

  The result of expression level analysis is shown in FIG. 3A and 3B show no treatment (Cont), L-carbocysteine added (S-CMC), tobacco smoke extract added (CSE), and tobacco smoke extract and L-carbocysteine added (CSE + S). -CMC) is the result of analyzing the mRNA expression level of antioxidant stress enzymes (HO-1, GCLM). 3 (C) and (D) show no treatment (Cont), N-acetyl-L-cysteine added (NAC), tobacco smoke extract added (CSE), and tobacco smoke extract and N-acetyl-L- It is the result of analyzing the mRNA expression level of antioxidant stress enzyme (HO-1, GCLM) when cysteine is added (CSE + NAC).

  As shown in FIGS. 3 (A) and 3 (B), the relative expression level of antioxidant stress enzymes (HO-1, GCLM) was increased by the addition of L-carbocysteine (“Cont” vs. “S-CMC”). Similarly, when under oxidative stress, the relative expression level of the antioxidant stress enzyme was increased by the addition of L-carbocysteine (“CSE” vs. “CSE + S-CMC”). Further, the amount of increase when under oxidative stress was extremely high compared to the amount of increase when not under oxidative stress. That is, it was shown that L-carbocysteine has an action of further promoting the expression of an antioxidant stress enzyme induced by oxidative stress.

  As shown in FIGS. 3C and 3D, even when N-acetyl-L-cysteine was added, the relative expression level of the antioxidant stress enzyme did not increase, but rather decreased (“Cont” vs. “ NAC "). Furthermore, when under oxidative stress, the relative expression level of antioxidant stress enzymes was significantly reduced by the addition of N-acetyl-L-cysteine (“CSE” vs. “CSE + NAC”).

  From this, it can be said that the action of promoting transcription of the transcription factor Nrf2 into the nucleus and the action of inducing and promoting the expression of the antioxidant stress enzyme are extremely surprising effects unique to L-carbocysteine.

Claims (7)

  An antioxidant stress enzyme expression inducer comprising L-carbocysteine or a pharmaceutically acceptable salt thereof as an active ingredient.   The antioxidant stress according to claim 1, wherein the antioxidant stress enzyme is one or more selected from the group consisting of an antioxidant enzyme, a detoxifying enzyme (phase 2 detoxifying enzyme), a drug transporter, and a ubiquitin proteosome. Enzyme expression inducer.   The antioxidant stress enzyme expression inducer according to claim 1 or 2, further comprising an antioxidant.   An antioxidant stress enzyme expression promoter comprising L-carbocysteine or a pharmaceutically acceptable salt thereof as an active ingredient.   The antioxidant stress according to claim 4, wherein the antioxidant stress enzyme is one or more selected from the group consisting of an antioxidant enzyme, a detoxifying enzyme (phase 2 detoxifying enzyme), a drug transporter, and a ubiquitin proteosome. Enzyme expression promoter.   A Nrf2 activator comprising L-carbocysteine or a pharmaceutically acceptable salt thereof as an active ingredient.   A Nrf2 nuclear translocation promoter comprising L-carbocysteine or a pharmaceutically acceptable salt thereof as an active ingredient.