Influence of Oxidative and/or Reductive Treatment on Human Hair (II): Effect of Hydrophilic Extracts from Rosmarinus officinalis L. on Oxidative and/or Reductive Hair-Damage

Abstract

To confirm the effects of hydrophilic extracts from Rosmarinus officinalis L. (HER) on oxidative and/or reductive hair-damage, we first estimated the HER antioxidant effect by doing a β-carotene decoloring test. We additionally conducted an analysis of the biochemical parameters, for example cysteic acid or chemiluminescence (CL), and observed the morphological changes (snapping and splitting frequency) after chemical and physical hair treatment. Furthermore, we compared the effect of applying HER with the effect of applying no antioxidant or the effect of a typical hydrophilic antioxidant, ascorbic acid (AsA). HER had a strong antioxidant effect in the hydrophilic radical generation system in the β-carotene decoloring test. However, HER exhibited moderate antioxidant effects in the lipophilic radical generation system. Concerning hair-damage, applying HER suppressed cysteic acid in the hair after chemical and physical treatment more than when no antioxidant is applied. In addition, HER and AsA application also suppressed CL intensity in the damaged hair in the system using 2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazin-3-one hydrochloride (MCLA). However, HER only exhibited a tendency for CL reduction in damaged hair when we induced CL with short time irradiation of ultraviolet rays (UV) without chemical reagents. Furthermore, HER and AsA suppressed the snapping and splitting frequency in the hair, and the suppression level of HER tended to be stronger than that of AsA. HER demonstrated the antioxidant effect in a hydrophilic radical generation system. Furthermore, HER could prevent oxidation and morphological changes in damaged hair that was subjected to oxidative and/or reductive treatment, such as perming and bleaching, as well as physical treatment, which is postulated to cause hair-damage in daily life.