Morphological and Chemical Composition Characterization of Commercial Sepia Melanin

Abstract

Melanins are difficult to characterize because of their intractable chemical properties and the heterogeneity in their structural features. Melanin pigments, in fact, are composed of many different types of monomeric units that are connected through strong carbon-carbon bonds. Its high insolubility and undefined chemical entities are two obstacles in its complete characterization. The morphological characterization and particle size distribution for sepia melanin by Scanning Electron Microscopy (SEM) on surface structure and Transmission Electron Microscopy (TEM) to confirm the morphology obtained from SEM was done. Both results show that Sepia melanin is formed by many aggregates agglomerated together. These aggregates are formed also by small spherical granules with different size distributions that have been determined using image-J software. The small granule diameter obtained from different TEM and SEM micrographs were 100-200nm. EDS reveals that C and O were the most abundant in sepia melanin with concentration average concentrations of about 57% and 24% respectively. The major compositions of sepia melanin are C, O, Na, Cl, while the minor are Mg, Ca, K, S and N. From TEM micrograph at high resolution, it was possible to measure the distance between polymers layers of sepia melanin using image-J software and it was 0.323 nm = 3.23 A.

Antioxidant, antibacterial properties and the light barrier assessment of raw and purified melanins isolated from Citrullus lanatus (watermelon) seeds

“…Melanins may be extracted only in alkaline conditions, thus in previous works conducted by other authors, using organic solvents and water were possibly not considered as a constituent of total antioxidants of C. lanatus seeds. The high antioxidant activity of melanins isolated from various sources have been reported by the other authors [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”

“…Melanins have been isolated from a variety of phylogenic sources: animals [14], plants (including seeds) [15][16][17][18][19][20][21], bacteria [22,23] and fungi [24,25]. Melanins are commonly represented as black and brown pigments, the high molecular weight heterogenous polymers derived from the oxidation of monophenols and subsequent polymerization of intermediate o-diphenols and quinones [26].…”

“…Melanins are commonly represented as black and brown pigments, the high molecular weight heterogenous polymers derived from the oxidation of monophenols and subsequent polymerization of intermediate o-diphenols and quinones [26]. Melanins are types of pigments, possessing broad biological activities including antioxidant, radioprotective, thermoregulative, chemoprotective, antitumor, antiviral, antimicrobial, immunostimulating and anti-inflammatory [14][15][16][17][18][19][20][21][22][23][24][25][26]. Based on these features, natural melanin has the potential to be of great value and application in the fields of pharmacology, cosmetics and functional foods [27].…”

Visible Light TiO2 Photocatalyst Composite Based on Carbon Microfiber Derived from Human Hair

“…These peaks are indicative of the structure of melanin (cuticle and cortex) . The spectral bands at 2770–3015 cm −1 and 3200–3400 cm −1 indicate the presence of C−H and hydroxyl groups, respectively . Nevertheless, the peaks decreased and disappeared after the heat increased to 350 °C due to excessive etching of human hair, which resulted in the removal of carbon and other functional groups.…”

Preparation of Naturally Active Melanin Nano‐Platforms Chelated with Barium Ions as a Potential X‐Ray‐Computed Tomography Contrast Agent

“…Figure a) shows the FTIR spectrum of extracted melanin from black hair. The peak at 3064 cm −1 can be attributed to aromatic C−H stretching, and the peak at 3279 cm −1 can be recognized as the O−H and N−H stretching vibrations of the carboxylic and phenolic OH as well as amine groups in the indolic and pyrrolic systems and amino acids ,. Two absorption peaks at 2929 cm −1 and 2869 cm −1 are the characteristic of aliphatic C−H stretching modes .…”