Chemical Composition, Tyrosinase Inhibitory Activity and Antibacterial Activities of Coconut Coir Dust Extract

Coconut industrial waste, particularly coconut coir dust, is an abundant and underutilized agricultural biomass. A large amount of coconut coir dust is generated during the extraction of coir fiber from coconut husk and accumulates as a waste product. The phenolic phytochemicals in coconut coir dust are considered a rich source with potential applications in a wide range of industries. Therefore, this study aims to assess the extract from coconut coir dust, a plentiful agricultural by-product of the coconut industry, as a potential source of natural components for skincare and cosmetic products. The bioactive compounds from coconut coir dust were extracted by ultrasound-assisted solvent extraction. The chemical composition of the coconut coir dust extract was determined by liquid chromatography-electrospray ionisation-mass spectrometer (LC-ESI-MS) and five bioactive compounds were identified. The extract was also evaluated for tyrosinase inhibitory activity by the mushroom tyrosinase inhibitory assay. Antibacterial activity was tested against the three human pathogenic strains including Staphylococcus aureus, Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus (MRSA). Results revealed that the extract exhibited tyrosinase inhibitory activity with an IC50 value of 874.17 µg/mL and showed antibacterial activities against all the tested bacterial strains. Minimal inhibitory concentration (MIC) values ranged from 0.80 - 25.60 mg/mL and minimal bactericidal concentration (MBC) values ranged from 3.20 - 120.40 mg/mL. In the light of this, coconut coir dust extract has the potential to replace artificial chemicals in skincare and cosmetic applications.