A holistic anti-aging approach applied in selected cultivated medicinal plants: A view of photoprotection of the skin by different mechanisms

Medicinal plants are recognized by their large number of bioactive secondary metabolites. They have been used to treat several human ailments and are believed to possess many biological activities. However, little is known about the photoprotective and anti-aging properties of important medicinal plants as assessed by integrative studies. To find new bioactive ingredients of cosmetic interest, seven cultivated medicinal plants were systemically evaluated in an integrated manner. Extracts obtained from each species using solvents of diverse dielectric constants were tested on different molecular targets related to skin aging, with a focus on the protection of the main components of the extracellular matrix (ECM). Thus, the inhibition of the enzymes collagenase, elastase and hyaluronidase was determined, and antioxidant properties were evaluated. Subsequently, a photoprotective approach was taken in human dermal fibroblasts (HDF) stimulated with ultraviolet B (UVB)-radiation through the measurement of matrix-metalloproteinases (MMP-1) and procollagen production, as well as intracellular reactive oxygen species (ROS) levels, in pretreatment with bioactive extracts. The species with higher biological activity were chemically characterized through fingerprint analysis by HPLC-DAD and comparison with reference standards. The results showed the ability of some extracts from Rosmarinus officinalis, Thymus vulgaris and Smallanthus sonchifolius to protect the major components of the ECM from UVB irradiation-induced damage. Additionally, useful information, including various bioactivities and the chemical diversity of the extracts of medicinal plants, which could not be acquired from individual assessments of anti-aging activity, was obtained using a holistic anti-aging approach.