1 2 hexanediol

The development of the SSE ingredient was previously described in [8 (link)]. In short, straw provided by Raízen from São Paulo, Brazil, underwent a milling and drying process. A solid–liquid extraction using 50% ethanol (v/v) (Honeywell, Morris Plains, NJ, USA) was performed, followed by purification using amberlite XAD-2. To obtain a powder, the resulting straw extract was freeze-dried (Martin Christ, Osterode am Harz, Germany). The SSE ingredient was obtained by mixing the dry sugarcane straw extract (20% wt) with 1,2-hexanediol (Sigma-Aldrich, St. Louis, MO, USA), a cosmetic solvent, in a 25:75 ratio (w/v) with water.

1,2-Pentanediol, 2-methyl-2,4-pentanediol, and 1,2-hexanediol (Sigma-Aldrich Chemie GmbH, Taufkirchen, Germany), polysorbate 60 (Kolliphor PS 60, BASF SE, Ludwigshafen, Germany), cetostearyl alcohol (Kolliwax CSA, BASF SE, Ludwigshafen, Germany), glycerol 85% (Dr. Willmar Schwabe GmbH & Co. KG, Karlsruhe, Germany), white soft paraffin (Sasol Performance Chemicals, Hamburg, Germany), potassium sorbate (Caesar & Loretz GmbH, Hilden, Germany), citric acid (Jungbunzlauer Suisse AG, Basel, Switzerland). 1,2-Octanediol (dermosoft Octiol) was kindly donated by Evonik Dr. Straetmans GmbH, Hamburg, Germany.

The dry birch bark extract was a gift from Amryt AG (Niefern-Oeschelbronn, Germany). It was produced by enhanced organic solvent extraction using n-heptane [5 ]. The chemical and physical characterization of the extract is shown in Table 1.
1,2-Propanediol was obtained from Caesar & Loretz GmbH (Hilden, Germany). Methanol, ethanol, butanol, octanol, ethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 1,9-nonanediol, adipic acid, and azealic acid were purchased from Sigma Aldrich (Taufkirchen, Germany) with a purity >95%. Succinic acid was from Merck KGaA (Darmstadt, Germany) and 1,2-pentanediol was from BASF (Zurich, Switzerland).