Development and application of magnolol derivative in cosmetics
94
Presented by: Bing Zhang
Introduction:
Magnolia officinalis is the dried bark, root bark and branch of magnolia officinalis, which is an important Chinese herbal medicine. The main chemical active components of Magnolia officinalis are lignans, magnolol, honokiol and etc. Especially, the phenolic active ingredient magnolol has many efficacies, such as antibacterial, anti-tumor, analgesic, anti-inflammatory. However, due to the poor water solubility, and it is easily oxidized and deteriorated, the efficacies of magnolol are difficult to demonstrate. Although addition of large amount of polyols and emulsifiers can increase the solubility of magnolol in cosmetic products, its application in water-based formula is still limited. One strategy that can solve the solubility problem is the introduction of hydrophilic functional groups to magnolol through chemical modification. Such magnolol derivative with novel chemical structure is expected to have higher efficiency and facilitate the application of magnolol in water-based cosmetics products.
Methods :
Synthesis of magnolol derivative:
Magnolol has two active α hydrogens in its molecular structure, which can undergo Mannich reaction with secondary amines and aldehydes. Magnolol derivatives were synthesized by reacting magnolol with diethanolamine and formaldehyde. Magnolol derivative retain allyl and phenolic hydroxyl groups in the structure, so they have certain antibacterial ability. At the same time, the structure of diethanolamine was introduced to magnolol, which significantly enhanced the water solubility of the active ingredient.
Cells experiments:
We conducted cell experiments to evaluate safety of both samples by HaCaT cells. Different amounts of magnolol derivative and magnolol were set to confirm the safety dose to HaCaT cells by CCK-8 assay.
Minimal inhibitory concentration MIC test:
Referring to the requirements of the "Technical Specification for Safety of Cosmetics" (2015 edition), the MIC of magnolol derivative to 5 kinds of microorganisms commonly found in cosmetics was determined by half-dilution method.
Anti-inflammatory activity test:
The anti-inflammatory effect of magnolol derivatives on the expression of IL-6 in HaCaT cells was detected by Western blot. The principle of this method is to combine protein with specific antibody and detect its expression.
Antioxidant test:
1,1-diphenyl-2-hydrazine (DPPH) can bind to free radicals. Its alcohol solution is dark purple and has strong absorption at 520nm. When there is a free radical scavenger, its alcohol solution will fade. Therefore, the free radical scavenging ability of the sample can be quantitatively analyzed by measuring the decrease of its absorbance.
Results:
Synthesis of magnolol derivatives:
The structure of magnolol derivative was determined by NMR, and the purity of magnolol derivative was more than 98%. The solubility of magnolol derivative was more than 100000ppm.
Cells experiments:
The cytotoxicity of magnolol derivative was about 8 times lower than that of magnolol.
Minimal inhibitory concentration MIC test:
Magnolol derivative has strong antibacterial activity against 5 kinds of microorganism commonly found in cosmetics. Especially the MIC against Pseudomonas Aeruginosa and Aspergillus Niger reached 0.08%. Magnolol derivative used as preservatives in water-based skin care formula (without any other preservatives). Only 0.38% addition of magnolol derivative was required to pass the 28-day Preservative efficacy testing (USP 51，EP 7.0).
Anti-inflammatory activity test:
Western Blot was used to detect IL-6 inflammatory factor protein in HaCaT cells induced by UVB radiation. The results showed that when HaCaT cells were irradiated with UVB, the expression of IL-6 inflammatory factor protein increased. After adding 70ppm magnolol derivatives and 70ppm magnolol, the expression of IL-6 protein decreased compared with UVB group. At the same time, these results suggest that magnolol derivatives may have better anti-inflammatory effect than magnolol.
Antioxidant test:
According to the DPPH test results, when the dosage of magnolol derivatives was 1000 ppm, the DPPH clearance rate reached 86.09%.
Conclusions& Discussion
Magnolol derivative has very good water solubility and is less toxic to skin cells than magnolol. Magnolol derivative has broad antibacterial spectrum and anti-inflammation effect, which is a promising new active ingredient for high-end skin care products.
Magnolia officinalis is the dried bark, root bark and branch of magnolia officinalis, which is an important Chinese herbal medicine. The main chemical active components of Magnolia officinalis are lignans, magnolol, honokiol and etc. Especially, the phenolic active ingredient magnolol has many efficacies, such as antibacterial, anti-tumor, analgesic, anti-inflammatory. However, due to the poor water solubility, and it is easily oxidized and deteriorated, the efficacies of magnolol are difficult to demonstrate. Although addition of large amount of polyols and emulsifiers can increase the solubility of magnolol in cosmetic products, its application in water-based formula is still limited. One strategy that can solve the solubility problem is the introduction of hydrophilic functional groups to magnolol through chemical modification. Such magnolol derivative with novel chemical structure is expected to have higher efficiency and facilitate the application of magnolol in water-based cosmetics products.
Methods :
Synthesis of magnolol derivative:
Magnolol has two active α hydrogens in its molecular structure, which can undergo Mannich reaction with secondary amines and aldehydes. Magnolol derivatives were synthesized by reacting magnolol with diethanolamine and formaldehyde. Magnolol derivative retain allyl and phenolic hydroxyl groups in the structure, so they have certain antibacterial ability. At the same time, the structure of diethanolamine was introduced to magnolol, which significantly enhanced the water solubility of the active ingredient.
Cells experiments:
We conducted cell experiments to evaluate safety of both samples by HaCaT cells. Different amounts of magnolol derivative and magnolol were set to confirm the safety dose to HaCaT cells by CCK-8 assay.
Minimal inhibitory concentration MIC test:
Referring to the requirements of the "Technical Specification for Safety of Cosmetics" (2015 edition), the MIC of magnolol derivative to 5 kinds of microorganisms commonly found in cosmetics was determined by half-dilution method.
Anti-inflammatory activity test:
The anti-inflammatory effect of magnolol derivatives on the expression of IL-6 in HaCaT cells was detected by Western blot. The principle of this method is to combine protein with specific antibody and detect its expression.
Antioxidant test:
1,1-diphenyl-2-hydrazine (DPPH) can bind to free radicals. Its alcohol solution is dark purple and has strong absorption at 520nm. When there is a free radical scavenger, its alcohol solution will fade. Therefore, the free radical scavenging ability of the sample can be quantitatively analyzed by measuring the decrease of its absorbance.
Results:
Synthesis of magnolol derivatives:
The structure of magnolol derivative was determined by NMR, and the purity of magnolol derivative was more than 98%. The solubility of magnolol derivative was more than 100000ppm.
Cells experiments:
The cytotoxicity of magnolol derivative was about 8 times lower than that of magnolol.
Minimal inhibitory concentration MIC test:
Magnolol derivative has strong antibacterial activity against 5 kinds of microorganism commonly found in cosmetics. Especially the MIC against Pseudomonas Aeruginosa and Aspergillus Niger reached 0.08%. Magnolol derivative used as preservatives in water-based skin care formula (without any other preservatives). Only 0.38% addition of magnolol derivative was required to pass the 28-day Preservative efficacy testing (USP 51，EP 7.0).
Anti-inflammatory activity test:
Western Blot was used to detect IL-6 inflammatory factor protein in HaCaT cells induced by UVB radiation. The results showed that when HaCaT cells were irradiated with UVB, the expression of IL-6 inflammatory factor protein increased. After adding 70ppm magnolol derivatives and 70ppm magnolol, the expression of IL-6 protein decreased compared with UVB group. At the same time, these results suggest that magnolol derivatives may have better anti-inflammatory effect than magnolol.
Antioxidant test:
According to the DPPH test results, when the dosage of magnolol derivatives was 1000 ppm, the DPPH clearance rate reached 86.09%.
Conclusions& Discussion
Magnolol derivative has very good water solubility and is less toxic to skin cells than magnolol. Magnolol derivative has broad antibacterial spectrum and anti-inflammation effect, which is a promising new active ingredient for high-end skin care products.