Bioactivities of Hydrophobic Corn Silk Peptide on Skin Cells

Leong, Seng Yi (2022) Bioactivities of Hydrophobic Corn Silk Peptide on Skin Cells. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Human skin is constantly experiencing oxidative stress due to the ROS production, and the depletion of intracellular antioxidant can be destructive to the skin cells. Bioactive peptides have been known for their ability to promote health via different mechanisms. Discovery of bioactive peptides from corn silk could encourage the channelling of corn silk waste into useful materials with pharmaceutical values. Previous research had analysed the potential antioxidant activities of the identified peptides from trypsinized corn silk proteins via in vitro and in silico approaches. Hence, this study aims to evaluate the skin-whitening and antioxidant properties of a peptide obtained from the corn silk hydrolysate. Anti-tyrosinase activity of the CSP was tested in vitro using tyrosinase to evaluate the skin-whitening ability. MTT assay was used to evaluate the cytotoxicity of CSP on HaCaT cells, while DCFH-DA assay was used to determine the cellular antioxidant activity of CSP. Results showed that CSP could inhibit tyrosinase enzyme in a dose-dependent manner. The peptide did not cause reduction in cell viability for the tested concentrations up to 150 μg/mL. Direct effect of peptide against the endogenous ROS in HaCaT cell line was observed, such that ROS production in peptide-treated cells were the same as untreated control. However, the peptide did not protect cells from external ROS, as the sample groups showed similar ROS production with the positive control. Hypothesis relating to the low solubility of hydrophobic CSP leading to lac of validity of the results of all performed cellular studies, and solutions for peptide delivery into the cell were proposed. In conclusion, the corn silk peptide may have the potential to be applied in cosmeceutical products as the skin-whitening ingredients. Further studies using proper peptide delivery system are needed to ensure a valid analysis of the bioactivities of the CSP on skin cells