Elucidation of Active Principles of Psoralea corylifolia and Withania somnifera and Evaluation of its Mechanism on Melanocytes with Reference to Repigmentation

Abstract

Melanin is the natural polymer pigment responsible for imparting colour to the skin, hair, and eyes as well as provides the photoprotection of the skin against ultraviolet radiation. Discrepancies in the control mechanism of normal pigmentation result in the onset of disturbed melanogenesis pathways which ultimately lead to various dermatological or aesthetic problems, such as hyperpigmentation or hypopigmentation. Hypopigmentary disorders affect either normal numbers of melanocytes or show rigorous defects in the site or amount of melanin. The regulation of melanin production is an important strategy in the treatment of abnormal skin pigmentation for the cosmetic and medicinal purposes. Conventional therapies employed for the treatment of hypopigmentation include treatment with corticosteroids, ultra violet radiations, lasers, depigmentation, and camouflage are only partially effective have associated side effects and the indefinite possibility of relapse generally make patients dissatisfied with the treatment. The use of herbs and their active principles are found to be safer, healthier, and milder than synthetic products for the treatment of skin hypopigmentation. During the period of present study in this thesis, extraction and characterization of the seeds of Psoralea corylifolia and the roots of Withania somnifera for active principles isolation was done by using High-Performance Liquid Chromatography (HPLC) and Liquid Chromatography Mass Spectrometry (LC-MS). Further to confirm its antimelanolytic activity, in vivo studies have been investigated for the development of skin darkening agents using zebrafish (Danio rerio) animal model. Findings showed that selected crude extracts enhance melanin content in zebrafish embryos. This enhancement of melanin content was through the activation of tyrosinase enzymes, which was confirmed by examining the activity of tyrosinase enzymes. Tyrosinase enzyme activation was assessed spectrophotometrically. Results showed that crude extracts of plants significantly enhanced