Photo-protective effect of cuttlefish ink melanin on human hair

Abstract

The photoprotective properties of exogenous melanin extracted from cuttlefish ink on human hair was assessed. Melanin extracted from cuttlefish ink was applied on black hair and irradiated using a solar simulator. The extent of photodegradation was determined by microstructural, morphological and mechanical testing. The UV–Vis spectra of melanin extracted from cuttlefish ink indicated strong absorption at UV region and moderate absorption in visible region. The melanin-coated samples indicated significant protection to hair cuticle against UV radiations, as indicated by microscopic images (SEM). Conversely, visible cracks were evident on uncoated hair shafts, when exposed to UV-radiations. Also, the melanin-coated hair samples indicated negligible alterations in disulfide linkages, free sulfhydryl group content, water retention index and swelling index on UV exposure, as compared to that of uncoated samples. Similarly, the mechanical strength of the uncoated hair fibers was far compromised by UV irradiation compared to that of melanin-coated hair fibers. The observations of the present study postulate cuttlefish melanin as a potential photoprotective agent in hair-care formulations, which is otherwise considered as a process discard from cephalopod processing industry.