Multifunctional hair cosmetic active raw material as well as preparation method and application thereof

Abstract

The invention discloses a multifunctional hair cosmetic active raw material as well as a preparation method and application thereof. The active raw material is cystine dimaleate amide. The disulfide bond-containing molecule with a symmetric maleic acid structure is used as a sulfydryl reconnection reagent, so that a traditional oxidized sulfydryl reconnection reagent represented by hydrogen peroxide, bromate, iodate and the like is avoided, the content of the disulfide bond in hair is maintained while the hair is shaped, and particularly, after multiple times of perming, the hair is more comfortable to use. Compared with the prior art that a large amount of disulfide bonds are consumed after perming, the supplement and the shaping method are used for perming, so that the hair can be effectively and repeatedly permed according to the willingness of consumers, and the hair styles can be changed for multiple times.

Description

Technical Field

[0001] This invention belongs to the field of cosmetic technology, specifically relating to a multifunctional active ingredient for hair cosmetics, its preparation method, and its application. Background Technology

[0002] The main component of hair is keratin, which is characterized by a large amount of cysteine. Disulfide bonds are formed between the sulfhydryl groups of every two cysteine ​​residues, thus maintaining the hair structure. With the improvement of people's living standards, the demand for beauty has become more urgent. Since the invention of chemical cold perming technology in the 1940s, people have enjoyed extremely convenient hair styling services. Chemical cold perming can be simply considered as a two-step process: first, a reducing agent (such as thioglycolic acid) is used to reduce the disulfide bonds in hair keratin to sulfhydryl groups; then, an oxidizing agent (such as hydrogen peroxide) is used to oxidize the sulfhydryl groups, causing them to reconnect and form disulfide bonds, while simultaneously giving the hair a macroscopic style.

[0003] Chemical perms offer convenience, but they can severely damage hair. For example, they can damage the hair's hydrophobic layer, leading to dryness and dullness, and damage the melanin within the hair, causing color fading. Most importantly, and what consumers value most, is that perms make hair brittle and prone to breakage. This is because oxidizing agents cause the excessive oxidation of disulfide bonds in the hair to sulfonate, resulting in a decrease in disulfide bond content. The disulfide bond content is crucial for hair's shape, strength, and stability. Therefore, oxidative perms reduce the disulfide bond content in hair keratin, which in turn reduces the α-helix content, increasing hair brittleness and reducing its resilience. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for synthesizing molecules that can both perm hair and replenish disulfide bonds, as well as resist hair photoaging and inhibit Propionibacterium acnes. The method successfully maintains the disulfide bond content of permed hair and can be used for repeated perming to change the style, prevent hair photoaging, and inhibit Propionibacterium acnes.

[0005] As one aspect of the present invention, the present invention provides a multifunctional active ingredient for hair cosmetics, wherein the active ingredient is dimaleic cystine amide, and its structural formula is as follows:

[0006] .

[0007] The present invention also provides a method for preparing the aforementioned multifunctional hair cosmetic active ingredient, which includes the following steps:

[0008] L-cystine disodium salt and maleic anhydride were dissolved in water and reacted under alkaline conditions and an ice bath. After the reaction was completed, a solution containing dimaleate cystine amide was obtained.

[0009] The molar ratio of maleic anhydride to L-cystine disodium salt is (1.5~2.5):1, and the pH of the reaction system is maintained at 9~11.

[0010] As a preferred embodiment of the preparation method of the multifunctional hair cosmetic active raw material of the present invention, the concentration of maleic anhydride is 5~10 wt%.

[0011] As a preferred embodiment of the preparation method of the multifunctional hair cosmetic active raw material of the present invention: the reaction is carried out under ice bath conditions of 0~5°C for 20~40 minutes.

[0012] The present invention also provides the application of the aforementioned multifunctional hair cosmetic active ingredient in the preparation of hair perming or straightening cosmetics, characterized in that: the active ingredient, as a supplement or styling agent, crosslinks with free thiol groups in hair keratin through a thiol-olefin click addition reaction.

[0013] The mass fraction of dimaleic cysteine ​​amide in the supplement or styling agent is 1% to 5%, the pH value during use is 7 to 10, and the treatment temperature is 30 to 50°C.

[0014] The present invention also provides the application of the aforementioned multifunctional hair cosmetic active ingredient in the preparation of hair photoprotective cosmetics.

[0015] The cosmetic product is used to reduce reactive oxygen free radicals generated in hair under ultraviolet radiation.

[0016] The beneficial effects of this invention are as follows: This invention uses a symmetrical maleic acid molecule containing disulfide bonds as a thiol relinking agent, avoiding the use of traditional oxidative thiol relinking agents such as hydrogen peroxide, bromate, and iodate. While styling the hair, it maintains the disulfide bond content in the hair, especially after multiple perms, the disulfide bond content in the permed hair is still maintained. Compared with the existing technology where disulfide bonds are largely consumed after perming, using the supplement and styling method of this invention for perming can effectively allow for repeated perming according to the consumer's wishes, and multiple changes to the hair style.

[0017] This invention utilizes a symmetrical maleic acid molecule containing disulfide bonds as a hair photoprotectant. The maleic acid structure effectively removes exogenous copper ions from the hair, fundamentally interrupting the copper ion-mediated Fenton-like reaction under ultraviolet light and preventing the excessive generation of reactive oxygen species. The disulfide bonds in the cysteine ​​structure preferentially replace the hair's own disulfide bonds to withstand ultraviolet damage, thereby protecting the integrity of the hair keratin structure. Simultaneously, this molecule also has a certain inhibitory effect on the proliferation of Propionibacterium acnes. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, wherein:

[0019] Figure 1 The structural features of dimaleate cystine amide in this invention 1 H-NMR spectrum.

[0020] Figure 2 The above are liquid chromatograms of synthesis examples 1, 2, and 3 of the present invention.

[0021] Figure 3 The photos show the perming effect of Comparative Examples 1, 2, and 3 of Application Example 1 of this invention.

[0022] Figure 4 The perming efficiency of Application Example 1, Application Example 2, and Application Example 3 of the present invention are shown.

[0023] Figure 5 The Raman spectra and disulfide bond content of hair after multiple perming cycles in Example 1 of this invention, as well as the original hair, are shown in the graph.

[0024] Figure 6 The present invention uses hair after multiple perming in Example 1, and compares the proportions of keratin secondary conformation and disulfide bond conformation of hair after multiple perming with H2O2 and the original hair.

[0025] Figure 7 Example 2 of the present invention uses an inductively coupled plasma spectrometer to determine the copper content in hair treated with different methods.

[0026] Figure 8 Example 2 of this invention shows the results of fluorescence spectroscopy determination of the content of reactive oxygen species (ROS) in hair treated with different methods. Detailed Implementation

[0027] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to specific examples.

[0028] The hair supplement component bismaleic cystine amide of this invention is obtained by acylation reaction of L-cystine disodium salt and maleic anhydride.

[0029] The synthetic route for dimaleic cysteine ​​amide is as follows:

[0030]

[0031] Synthesis Example 1:

[0032] Add L-cysteine ​​disodium salt and maleic anhydride to an ice bath beaker, with sodium hydroxide as a pH adjuster, and add water as a solvent. Specific conditions are: n 马来酸酐 :n L-胱氨酸二钠盐 The ratio was 2:1, with maleic anhydride at a feed concentration of 6.9 wt%. Sodium hydroxide was added to maintain the pH at 10, and the reaction was carried out in an ice bath for 30 min to obtain an aqueous solution of the product. The structural characteristic spectrum of this molecule is shown in [reference needed]. Figure 1 .

[0033] Synthetic Comparative Example 1:

[0034] The difference from Synthesis Example 1 is that n 马来酸酐 :n L-胱氨酸二钠盐 =1:1, and all other synthesis conditions are the same.

[0035] Synthetic Comparative Example 2:

[0036] The difference from Example 1 is that sodium hydroxide was not used to adjust the pH to 10, but all other synthesis conditions were the same.

[0037] Synthetic Comparative Example 3:

[0038] The difference from Example 1 is that the reaction was carried out at room temperature, without ice bath conditions, while all other synthesis conditions were the same.

[0039] In Synthesis Example 1 and Comparative Examples 1-3, purity was calculated as the ratio of the characteristic peak area of ​​dimaleate cystine amide to the total peak area in liquid chromatography. The liquid chromatograms are shown below. Figure 2 See Table 1.

[0040] Table 1

[0041] Comparative Example 2 shows that the addition of maleic anhydride made the system acidic, causing cysteine ​​to precipitate completely and preventing the reaction from proceeding. This indicates that the amidation reaction requires an alkaline environment in the aqueous phase. The alkaline environment allows cysteine ​​to dissolve in the system and simultaneously deprotonates the amino group of the amino acid, releasing a free amino group that reacts with the organic acid anhydride to form an amide. Comparative Example 3 shows that the ice bath temperature inhibited the hydrolysis of the acid anhydride, ensuring that the anhydride reacted preferentially over the amino group, thus allowing the reaction to proceed effectively.

[0042] Application Example 1:

[0043] The hair disulfide bond supplement prepared in Synthetic Example 1 was used to supplement and stabilize disulfide bonds. The principle is that bismaleic cystine amide reacts with free thiol groups to achieve the relinking of free thiol groups. The reaction process is as follows:

[0044]

[0045] The preparation method of the hair disulfide bond supplement is as follows: Each component prepared in Application Example 1 and Comparative Examples 1-3 is added to water. After complete dissolution, the solution is cooled to room temperature, and then the pH is adjusted to 7-10 using a pH adjuster (see Table 2). As a supplement, the functional molecules recombine and stabilize the broken chemical bonds through a chemical reaction, thus promoting hair curling or straightening.

[0046] Table 2

[0047] Hair restoring agent conforms to the standard: Cold perm lotion for hair (GB / T 29678-2013).

[0048] To explore the optimal conditions for supplement use, different experiments were designed to style hair strands. The hair strands used were 22cm long black hair from healthy Chinese women.

[0049] (1) As shown in Table 2, apply the reducing agent to the hair, use a hot iron to heat the hair to 40°C for 30 minutes, rinse with water after heating, and shape the hair.

[0050] (2) Apply each group of supplements in Table 2 to the shaped hair and heat it according to the conditions given in Table 2. After the reaction is complete, rinse with water and blow dry the hair to complete the operation.

[0051] Perming effect test:

[0052] All hair strands used in this invention were washed with a 5 wt% sodium lauryl sulfate (SDS) solution, thoroughly rinsed with water, and air-dried at room temperature before use. The initial length of the test hair samples was 22 cm. The perming efficiency was calculated using the methods and formulas below.

[0053] Perming efficiency (%) = (Number of perms after perming / Fiber length after perming) * 100% / (Number of perms before perming / Fiber length before perming).

[0054]

[0055] Figure 3 Photos showing the perming effect of Application Example 1, Application Comparative Example 1, Application Comparative Example 2, and Application Comparative Example 3. Figure 4 The perming efficiency of Application Example 1, Application Example 2, and Application Example 3 are compared.

[0056] The comparison of perming results shows that Application Example 1 achieved excellent perming results with a perming efficiency of 1474%, while Comparative Example 1 showed almost no perming effect with a perming efficiency of only 317%. This indicates that perming with dimaleic cystine amide requires an alkaline environment. Comparative Examples 2 and 3 demonstrate that low concentration and low temperature reduce perming efficiency; Comparative Example 2 achieved a perming efficiency of 1276%, and Comparative Example 3 achieved a perming efficiency of 1062%. This demonstrates that achieving excellent perming results with dimaleic cystine amide requires maintaining a certain temperature and concentration. The application examples illustrate that maintaining a certain operating temperature and concentration under alkaline conditions allows for successful click perming with dimaleic cystine amide.

[0057] Disulfide bond supplementary test:

[0058] Following the application example 1 described above, the hair was subjected to a second and third treatment, and the changes in the chemical structure of the hair were analyzed using a Raman microscopy system. An excitation wavelength of 785 nm was used, within the range of 300–3200 cm⁻¹. -1 Raman spectra of the hair sample surface were collected within the spectral range. Since Application Example 1 underwent multiple treatments, to avoid confusion, the term "dimaleic cysteine ​​amide treatment (MA2-CySS perming)" was used. Hydrogen peroxide, the most commonly used substance in oxidative perming, was used as a comparison with conventional oxidative perming (H2O2 perming).

[0059] Calculations were made between 490 and 570 cm. -1 The characteristic peak area of ​​disulfide bonds is 1380~1500 cm⁻¹ -1 The ratio of the characteristic peak areas of carbon-hydrogen bonds was used to quantitatively analyze the disulfide bond content in hair samples. Using untreated hair (virgin hair) as a baseline, the disulfide bond content of permed hair was normalized and expressed as the residual disulfide bond percentage (SS-percentage).

[0060] Spectral simulations were performed on the amide I band region to quantitatively analyze the relative proportions of β-sheet / random coil (β / R) and α-helix (α) conformations in the secondary structure of hair keratin. Among them, 1671 cm... -1 The characteristic peak at 1652 cm⁻¹ belongs to the β / R conformation. -1 The characteristic peaks at the specified locations are attributed to the α conformation. The relative abundance of each secondary structure is determined by calculating the percentage of each characteristic peak area relative to the β / R ratio and the total peak area of ​​the α conformation.

[0061] By curve fitting of the characteristic peak region of disulfide bonds, the distribution ratio of different disulfide bond conformations was quantitatively analyzed. In the disulfide bond stretching vibration region, at 508 cm⁻¹... -1 The characteristic peak corresponds to the gauche-gauche-gauche (GGG) conformation, 524 cm⁻¹ -1 The characteristic peak at 544 cm⁻¹ corresponds to the gauche-gauche-trans (GGT) conformation. -1 The characteristic peaks correspond to the trans-gauche-trans (TGT) conformation. The relative content of each conformation is determined by calculating the percentage of the area of ​​each characteristic peak relative to the total peak area of ​​the disulfide bonds.

[0062] The structural characteristics of hair after multiple perming applications in Comparative Example 1 were characterized using Raman spectroscopy. The results are as follows: Figure 5 a. Hair perming three times with H2O2 at 1040 cm -1 -SO- 3 appears at ν s The characteristic vibrational peak (SO) indicates excessive oxidation during traditional oxidative perming, leading to the conversion of thiol groups and disulfide bonds into sulfonic acid groups. In stark contrast, hair treated with three MA2-CySS perming cycles did not exhibit ν... s The (SO) characteristic peak, whose spectral characteristics are completely consistent with Virginhair, proves that the molecule can effectively avoid the formation of sulfonic acid groups, thereby retaining the disulfide bond content.

[0063] Disulfide bond retention is a key factor in maintaining the stability of keratin's secondary structure. Raman spectroscopy analysis results show that... Figure 5 b. After three MA2-CySS perming treatments, the disulfide bond retention rate remained above 85%, while with the increase of the number of perming treatments, the disulfide bond retention rate of traditional H2O2 perming significantly decreased to 72%. This is due to the above-mentioned excessive oxidation causing thiol groups and disulfide bonds to be converted into sulfonic acid groups. This indicates that the supplement can effectively maintain and replenish the disulfide bond content in the hair.

[0064] Furthermore, the ordered keratin conformation (especially the α-helix) plays a crucial role in maintaining hair properties. By performing spectral simulations of the amide I band, the proportional distribution of keratin secondary structures after three perming sessions was calculated as follows: Figure 6 a. The results showed that the α-helix content of H2O2 perming decreased significantly from 30.07% to 24.35%. It can be inferred that excessive oxidation by H2O2 led to a structural transformation of keratin from α-helix to β-sheet / random coil. In contrast, the MA2-CySS perming maintained a higher α-helix ratio of 27.50%. Comprehensive analysis indicates that the sufficient retention of disulfide bonds after perming effectively maintained the ordered conformation of keratin, thus ensuring the integrity of the hair structure. To further explore the conformational differences of disulfide bonds in hair after MA2-CySS and H2O2 perming, the distribution ratio of different disulfide bond conformations was quantitatively analyzed by curve fitting of the characteristic spectral regions of disulfide bonds. Figure 6 As shown in b, both perming methods resulted in a decrease in GGG conformation content and an increase in TGT conformation content. The conformational change of MA2-CySS perming was particularly significant, with a GGG conformational conversion rate reaching 9%. This conformational change can be attributed to the cross-linking of different thiol groups within and between keratin chains by the supplement, promoting the transformation of disulfide bonds from the smallest bond length GGG conformation to the largest bond length TGT conformation. This also demonstrates that the introduced disulfide bonds exist in multiple conformations, further proving its efficacy and role as a disulfide bond supplement.

[0065] Application Example 2:

[0066] This molecule has excellent properties in preventing photoaging of hair. It not only chelates and removes photoaging caused by the increase in copper ion content in hair due to pollution such as tap water, but also uses its own disulfide bonds to protect the internal disulfide bonds of hair from being decomposed by light, thereby protecting the hair structure.

[0067] To simulate contamination, hair was immersed in a 0.1% CuCl2 aqueous solution at 40°C for 1 hour. It was then treated with a 2% MA2-CySS aqueous solution immersed at 40°C for 1 hour. The control group was immersed in water under the same conditions. The copper content in the hair was determined using inductively coupled plasma atomic absorption spectrometry (ICP-AES). Alternatively, hair was shredded, digested in aqua regia until clear, diluted to an appropriate concentration, and then analyzed using ICP-AES. The copper content was calculated based on a copper content standard curve, and the mass fraction of copper in the hair was calculated according to its mass. Figure 7 .

[0068] DCFH (2,7-dichlorodihydrofluorescein) was used as a fluorescent probe to test the reactive oxygen species (ROS) generated in hair due to photoaging under sunlight. DCFH is a non-fluorescent molecule that generates fluorescent 2,7-dichloroisochlorochlorophyll (DCF) upon contact with free radicals generated by ultraviolet radiation. DCFH was prepared by hydrolyzing 6 mL of 1 mM DCFH-DA in ethanol with 24 mL of 0.01 M NaOH solution. The reaction mixture was stabilized at room temperature in the dark for 30 min, then neutralized with 60 mL of PBS. The solution was stored at -4°C in the dark until further use. Hair contaminated with copper and treated with 2% MA2-CySS aqueous solution was exposed to a xenon lamp aging chamber for 15 days, then cut into approximately 2 mm segments. 50 mg of the sample was weighed, and 1 mL of DCFH solution was added. The mixture was incubated at 37°C in the dark for 90 min. After incubation, the solution was collected and filtered through a 0.45 μm organic filter membrane. The fluorescence intensity in the solution was measured using a fluorescence microplate reader with an excitation wavelength of λ=488 nm and an emission wavelength of λ=522 nm. Hair that was directly photoaged without contamination treatment and hair that was photoaged after copper contamination treatment with water were both placed in a xenon lamp aging chamber for the same duration. The relative ROS content was obtained by comparing the fluorescence intensity obtained from the experiment, with the hair that was directly photoaged without contamination treatment as 100%. Figure 8 .

[0069] The copper content and ROS of copper-contaminated hair increased significantly, reaching as high as 0.0031%. Conversely, the ROS content of copper-contaminated hair increased dramatically after photoaging, nearly three times higher than that of hair treated without contamination. This indicates that copper ions act as a powerful catalyst, significantly accelerating the oxidative damage of hair caused by ultraviolet radiation, catalyzing the oxidation of amino acids such as cysteine, tryptophan, and tyrosine, leading to the destruction of hair keratin structure. In contrast, hair treated with MA2-CySS showed a significant decrease in copper content to 0.00137%. Correspondingly, the ROS after photoaging was significantly lower than that of copper-contaminated hair, but slightly higher than that of hair treated without contamination. This suggests that MA2-CySS can effectively utilize its maleic acid groups to chelate copper ions, reducing the copper ion content in copper-contaminated hair and thus reducing ROS generation. Furthermore, it should be noted that the cysteine ​​within its molecule also effectively protects the cysteine ​​within the hair. Previous studies have shown that ultraviolet radiation degrades and breaks disulfide bonds, and the disulfide bonds of cysteine ​​within its molecule are preferentially degraded during photoaging, thus ensuring that the cysteine ​​disulfide bonds within the hair itself are not photodegraded.

[0070] This invention is based on a molecule derived from a thiol-olefin click addition reaction. This molecule possesses symmetrical maleic amide groups, which can cross-link with the thiol groups of hair keratin, thus achieving oxidant-free perming. The disulfide bonds within the molecule can replace the hair's own disulfide bonds, allowing the hair to be permed repeatedly. Simultaneously, this new molecule has a unique structure containing both maleic acid and cysteine, which can chelate and remove copper ions generated from hair due to pollution, thereby preventing copper ions from catalyzing photoaging and combating photoaging. The introduction of disulfide bonds further protects the hair's own disulfide bonds from UV degradation, combating photodegradation and protecting overall hair health. It has also been found to have a certain inhibitory effect on Propionibacterium acnes.

[0071] Explanation of the principle: This process involves the amidation reaction of L-cysteine ​​disodium salt and maleic anhydride in a low-temperature, alkaline-catalyzed aqueous environment to produce bismaleic cysteine ​​amide, which is then diluted to a specific mass fraction as a supplement. Thioglycolic acid is used to effectively break the disulfide bonds in keratin under low-temperature, weakly alkaline, and humid conditions, softening the hair. Simultaneously, the molecule contains a symmetrical structure of disulfide bonds and α-carbonyl carbon-carbon double bonds. Through a click addition reaction with a thiol-Michael reagent, the relinking of thiol groups is achieved at relatively low temperatures. This not only shapes the hair but also avoids oxidative damage to the hair strands. Furthermore, the introduction of new disulfide bonds not only replenishes and maintains existing disulfide bonds in the hair but also allows for repeated perming and styling, thus achieving the goal of repeated perming and restyling. This is of great significance for hair health.

[0072] Meanwhile, this molecule utilizes the chelating properties of maleyl groups to chelate and remove the increased copper content in hair caused by pollution, preventing copper-catalyzed photoaging of hair under ultraviolet light and preventing keratin oxidation and photoaging caused by excessive generation of reactive oxygen free radicals. It also utilizes the disulfide bonds of its internal cystine residues to protect the hair's own disulfide bonds, absorb ultraviolet damage, and thus protect the hair structure. These exogenous disulfide bonds can preferentially absorb and dissipate ultraviolet light energy, effectively reducing the direct photolytic breakage of the hair's own key disulfide bond network, thereby maintaining the integrity and mechanical strength of the keratin structure.

[0073] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A multifunctional active ingredient for hair cosmetics, characterized in that: The active ingredient is dimaleate cystine amide, and its structural formula is as follows: 。 2. The method for preparing the multifunctional hair cosmetic active ingredient according to claim 1, characterized in that: Includes the following steps: L-cystine disodium salt and maleic anhydride were dissolved in water and reacted under alkaline conditions and an ice bath. After the reaction was completed, a solution containing dimaleate cystine amide was obtained. The molar ratio of maleic anhydride to L-cystine disodium salt is (1.5~2.5):1, and the pH of the reaction system is maintained at 9~11.

3. The method for preparing the multifunctional hair cosmetic active ingredient according to claim 2, characterized in that: The concentration of maleic anhydride used in the feed is 5-10 wt%.

4. The method for preparing the multifunctional hair cosmetic active ingredient according to claim 2 or 3, characterized in that: The reaction was carried out in an ice bath at 0-5°C for 20-40 minutes.

5. The application of the multifunctional hair cosmetic active ingredient according to claim 1 in the preparation of hair perming or straightening cosmetics, characterized in that: The active ingredient, as a supplement or styling agent, crosslinks with free thiol groups in hair keratin via a thiol-olefin click addition reaction.

6. The application according to claim 5, characterized in that: The mass fraction of dimaleic cysteine ​​amide in the supplement or styling agent is 1% to 5%, the pH value during use is 7 to 10, and the treatment temperature is 30 to 50°C.

7. The application of the multifunctional hair cosmetic active ingredient according to claim 1 in the preparation of hair photoprotective cosmetics.

8. The application according to claim 7, characterized in that: The cosmetic product is used to reduce reactive oxygen free radicals generated in hair under ultraviolet radiation.

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