Hydroxycoumarins: Coumarins are lactones of phenyl propanoic acid with benzopyranone nucleus. The natural derivatives of coumarins include aloesin, which has been proven to have tyrosinase inhibitory properties. The hydroxycoumarins are novel antioxidants, which have alpha tocopherol like structure and strongly inhibit tyrosinase in cultured human melanocytes and cell homogenates, besides having scavenging and quenching activities.