Effects of Aloe vera Flower Extract and Its Active Constituent Isoorientin on Skin Moisturization via Regulating Involucrin Expression: In Vitro and Molecular Docking Studies

Skin moisturization is very crucial for maintaining the flexibility, viscoelasticity, and differentiation of the epidermis and its deprivation causes several diseases from dry skin to dermatitis. Aloe vera, a miracle plant having diverse medicinal properties including skin moisturization effects. This study investigated for the first time the molecular mechanism targeting skin moisturization effects of the Aloe vera flower and its major active constituent. By treating human epidermal keratinocytes (HaCaT cells) with Aloe vera flower water extract (AFWE), we found that AFWE upregulated epidermal involucrin by activating the expression of protein kinase C, p38, and ERK 1/2. Additionally, it modulated filaggrin, increased aquaporin expression, and hyaluronan synthesis via a balanced regulation of HAS1 and HYAL1 protein. Similarly, it was able to protect UVB-induced photodamage. Western blot analysis, ELISA, and qRT- PCR were performed to evaluate various epidermal differentiation markers and moisturization-related factors on human epidermal keratinocytes (HaCaT cells). TLC and HPLC were used to detect and analyze the chemical constituents. Among them, we found that an active component of Aloe vera flower, isoorientin (IO) has a high binding affinity to all of its targeted proteins such as involucrin, PKC, P38, etc. through molecular docking assay. This study indicated that the Aloe vera flower and its active constituent, IO can be used as a prominent ingredient to enhance skin barrier function and improve its related pathologies.