Quillaja saponin normalises dermal sebaceous imbalance

Due to their exceptional ability as a nonirritant tensioactive, quillaja extracts are widely used in cosmetics as a cleanser, foaming agent, emulsifier and dispersing agent, but its objective efficacy as a bioactive in skin treatment was never studied. Thus the aim of this study was to confirm the property of quillaja saponins to improve the condition of sensitive, greasy and acne-prone skin. Several objective dermatological evaluations, instrumental measures and selfperception of subjects confirmed that the quillaja extract is a mild cosmetic active ingredient that helps normalise seborrhoea and significantly improves the complexion of acne-prone skin. Desert King and its production affiliate, Natural Response, have worked with the Chilean National Forest Organization (CONAF) to pioneer the establishment of quillaja plantations and biomass supply. This reduces pressure on native forests and helps increase tree distribution, ensuring a durable supply for the quillaja saponin market for years to come. Quillaja saponins are extracted with an all-natural water process (no chemicals involved).
Plant saponins [Latin: sapo (soap)] are famous for their generally non-ionic surfactant properties due to their chemical structure of a lipophilic aglycone (terpen or steroid) and one or more hydrophilic sugar chain, whose identity is also responsible for their specific qualities.1 Saponin extracts are natural cleansers and foamers, but they are also known to exert a wide range of activities when used in food, feedstock or pharmaceutical applications.2,3 Plant saponins are also used as functional ingredients especially in natural cosmetics, but their properties as actives in cosmetics are rarely studied. Results from ginseng4 or green tea saponins5 and others confirmed the delay of skin ageing processes and acne prevention.6 Ancient knowledge and modern research in the field of food, feedstock and pharmacy, indicated that the triterpenic saponins of the Chilean soapbark tree Quillaja saponaria might have an exceptionally high potential to benefit cosmetics for certain skin disequilibrium. Bark extracts from Quillaja saponaria were traditionally used by the Mapuche Indians not only as a conditioning shampoo7 but also by their shamans as a medical treatment to cure cutaneous disorders8 like eczema, pityriasis9 and seborrhea.10 Widely used in food, the structure of the unique Quillaja saponaria saponins is now understood in detail11 and the extracts are known to show a very low toxicity profile.12 The proven mildness of quillaja extracts is all the more important for cosmetic applications for sensitive and inflammatory skin with open skin lesions. To guarantee consistent performance, refined and purely physical processing techniques were developed by Natural Response Chile to produce standardised quillaja extracts with guaranteed saponin content, which is independent of natural fluctuations. This is controlled for each batch by reverse HPLC.13 Moreover 100% natural organic Quillaja saponaria extracts for cosmetic use are harvested under sustainable forest management and from controlled plantations.14 Sustainability is a matter of growing importance, which benefits the environment and ensures sustainable product supply. We know Quillaja saponaria extracts work as foaming agents15 or natural emulsifiers16 for cosmetics. However, the precious bioactive properties of quillaja have just recently being published, and their value, as a cosmetic active ingredient, had not been proven by objective dermatological tests. This paper presents the results of a group of bioactive evaluations that confirm the capability of purified quillaja saponins to improve certain states of skin disequilibrium that are caused by excessive sebum production. 

Experimental conditions 

Preliminary tolerability studies have proven the mildness of Quillaja saponaria Andean Q Ultra extract (Desert King, San Diego, US). A human repeated insult patch test on 105 volunteers of different skin types did not show any irritant reactions or skin sensitisation.17 The Het Cam test (25 L to 125 L) classified Andean Q Ultra to be borderline minimal to mild ocular irritant.18 In order to test the potential capability of quillaja saponins to act as bioactive ingredient in the normalisation of the skin affected by excessive sebum production, we prepared an aqueous solution at 2% of Andean QDP Ultra Organic (Desert King, San Diego, US). This was slightly thickened with hydroxyethyl cellulose (Natrosol 250HHR – Hercules – at 1%) to facilitate easier handling. Besides a dermatological evaluation of the skin conditions, and an interview with the volunteers over their perceived efficacy of the treatment, the capability of the ingredient to normalise the skin pH and the amount of sebum was also checked. Twenty volunteers were selected between the ages of 18 and 50 years (average age 31.5). They were recruited according to the experimental criteria of having sensitive skin and objectively evaluated greasy skin. The preliminary skin sensitivity test was carried out according to the method developed by Frosch and Kligman.19 Stingers were identified by applying a 10% aqueous solution of lactic acid on their naso-labial fold and cheek and checking the stinging reaction after both 2.5 and 5 minutes. The dermatologist then evaluated the sebum content of the skin. After the initial baseline controls, subjects washed their face twice a day with a 2 mL dose of the above solution for 2 weeks. On the final day, the volunteers were required not to wash their face nor to apply any product at least 3 hours before the measurements. Three replicates of sebum measures were taken on the T-zone (forehead, nasolabialfold and chin) by a Sebumeter (SM810, Courage & Khazaka, Köln), which reflects the actual level of lipids on the skin by the degree of transparency induced by adhering lipids on an opaque tape. Standard reference values on the T line are: dry skin <100 g/cm2, normal skin 100-150 g/cm2, greasy skin >150 g/cm2. In order to check the potential normalising effect on skin pH, which is often influenced by seborrhoeic skin,20 measures were taken on the cheeks, by a pH meter (Courage & Khazaka). For the clinical evaluation of possible signs of intolerance scores on a 4-point clinical scale for erythema, desquamation, itching, swelling and burning, from 0 (absent) through to 3 (severe) was given. At the end of the study subjects were asked to classify the perceived efficacy of the product in decreasing the signs of greasy skin and in reducing redness, dryness and tightness with a 4-point intensity scale. The mathematical elaboration of results was carried out by applying normality tests (Kolmogorov-Smirnov, Lilliefors, Shapiro). Mean values and standard deviations were calculated for each set of measures (time: 0, 1 and 2 weeks). The analysis of variance for repeated measures and the Bonferroni test for parametric data were used for the statistical comparison. Further the clinical evaluations were statistically compared by means of Friedmans Anova and Kendall’s coefficient of concordance for nonparametric data. In both cases the results were considered statistically significant when the probability values were p<0.05.21