Magnolia extract offers broad and pH-independent antimicrobial properties. The minimum inhibitory concentration (MIC) against yeasts (C. albicans) and moulds (A. brasiliensis) is 0.01% [w/v].
In preservative efficacy tests, which reflect the performance in cosmetic formulations more effectively, 0.20% [w/v] has proven to be effective. However, due to its hydrophobic character, the extract should be combined with surface-active substances such as glyceryl caprylate and/or diols. Diols increase the solubility of the extract in the aqueous phase, whilst, as a co-emulsifier, glyceryl caprylate forces it into the interphase between water and oil. Both are crucial for the efficacy as bacteria, yeasts and moulds grow in the aqueous phase.
Oils and waxes can also be protected using magnolia extract as it has antioxidative properties. A comparison with mixed tocopherols shows that Magnolia Extract does not quite reach the performance of tocopherols, but has a significant effect.
Active ingredients are generally used in low concentrations in cosmetic products. Magnolia extract can also be used here thanks to its antimicrobial and antioxidative properties. It is particularly effective against tooth decay and periodontitis bacteria, and shows notable performance against skin bacteria responsible for the inflammatory process of acne. With a minimum inhibitory concentration (MIC) of 0.001% [w/v] against the abovementioned germs, the application concentration in face creams and oral care products is correspondingly low.
Antioxidants used as active ingredients must be bioactive in order to be accepted, transported and processed by the body. Magnolia extract is one of these substances. It is noteworthy that an antioxidative effect which is almost a thousand times higher than that of bioactive alpha-tocopherol has been demonstrated in numerous studies.
Magnolia extract thus offers properties for a very wide range of applications in absolute conformity with the principle of natural cosmetics.