Montra Srisayam1, Natthida Weerapreeyakul2, Sahapat Barusrux3, Waraporn Tanthanuch4, Kanjana Thumanu5. 1. Biomedical Science Program, Graduate School, Khon Kaen University, Khon Kaen 40002, Thailand. Electronic address: srisayam_ssy@hotmail.com. 2. Center for Research and Development of Herbal Health Products (CRD-HHP), Khon Kaen University, Khon Kaen 40002, Thailand; Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand. Electronic address: natthida@kku.ac.th. 3. Center for Research and Development of Herbal Health Products (CRD-HHP), Khon Kaen University, Khon Kaen 40002, Thailand; Centre for Research and Development of Medical Diagnostic Laboratories, Khon Kaen University, Khon Kaen 40002, Thailand; Faculty of Associate Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand. Electronic address: sahapat@kku.ac.th. 4. Synchrotron Light Research Institute (Public Organization), Nakhon Ratchasima 30000, Thailand. Electronic address: waraporn@slri.or.th. 5. Synchrotron Light Research Institute (Public Organization), Nakhon Ratchasima 30000, Thailand. Electronic address: kanjanat@slri.or.th.
Abstract
BACKGROUND: Hyperpigmentation is aesthetic undesirable. Sesamol and the standard antimelanogenic agent (kojic acid) were shown to hinder melanogenesis by blocking tyrosinase and reducing melanin content. OBJECTIVE: The FTIR microspectroscopy was used in an attempt to find a novel method to define biological alternation in a melanogenesis inhibition of sesamol and kojic acid. METHODS: Tyrosinase inhibition and melanin content of sesamol and kojic acid were evaluated. The FTIR microspectroscopy was adopted to define the vibrational characteristic involved with the melanogenesis in the untreated SK-MEL2 cells vs. the sesamol- and kojic-treated SK-MEL2 cells. RESULTS: Sesamol and kojic acid inhibited mushroom tyrosinase at IC₅₀ of 0.33 μg/ml and 6.1±0.4 μg/ml, respectively. Moreover, 30 μg/ml sesamol inhibited 23.55±8.25% cellular tyrosinase activity in human SK-MEL2 cells, while 600 μg/ml kojic acid inhibited 33.9±1.4% cellular tyrosinase activity in the same cells. In the SK-MEL2-treated with two inhibitors, the FTIR spectra assigned to the lipid and nucleic acid bands were significantly depleted with the secondary protein structure shifted to a more β-pleated secondary protein one. CONCLUSION: Both sesamol and kojic acid display a similar pattern of antimelanogenesis activity albeit to a different degree. The mechanism of their whitening effect may be via the alteration of (a) the enzyme conformation disallowing the ordinary enzyme-substrate interaction and maybe (b) the integrity of the lipid-containing melanosome. Our results support the alternative use of FTIR microspectroscopy as a simple and reagent-free method for characterization of biomolecular changes in human melanoma cells.
BACKGROUND: Hyperpigmentation is aesthetic undesirable. Sesamol and the standard antimelanogenic agent (kojic acid) were shown to hinder melanogenesis by blocking tyrosinase and reducing melanin content. OBJECTIVE: The FTIR microspectroscopy was used in an attempt to find a novel method to define biological alternation in a melanogenesis inhibition of sesamol and kojic acid. METHODS:Tyrosinase inhibition and melanin content of sesamol and kojic acid were evaluated. The FTIR microspectroscopy was adopted to define the vibrational characteristic involved with the melanogenesis in the untreated SK-MEL2 cells vs. the sesamol- and kojic-treated SK-MEL2 cells. RESULTS:Sesamol and kojic acid inhibited mushroomtyrosinase at IC₅₀ of 0.33 μg/ml and 6.1±0.4 μg/ml, respectively. Moreover, 30 μg/ml sesamol inhibited 23.55±8.25% cellular tyrosinase activity in human SK-MEL2 cells, while 600 μg/ml kojic acid inhibited 33.9±1.4% cellular tyrosinase activity in the same cells. In the SK-MEL2-treated with two inhibitors, the FTIR spectra assigned to the lipid and nucleic acid bands were significantly depleted with the secondary protein structure shifted to a more β-pleated secondary protein one. CONCLUSION: Both sesamol and kojic acid display a similar pattern of antimelanogenesis activity albeit to a different degree. The mechanism of their whitening effect may be via the alteration of (a) the enzyme conformation disallowing the ordinary enzyme-substrate interaction and maybe (b) the integrity of the lipid-containing melanosome. Our results support the alternative use of FTIR microspectroscopy as a simple and reagent-free method for characterization of biomolecular changes in humanmelanoma cells.