POTENCY OF BIOPIGMENTS FROM THE TROPICAL MARINE MICROALGAE NAVICULA SP. AS AN ANTIOXIDANT

• Main Author: UTAMI (NIM: 20511301) ; Pembimbing Dr. Santi Nurbaiti, Zeily Nurachman, D.Sc, ANDITA
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/17949
• Institution: Institut Teknologi Bandung

Biopigments known as a colored substance that is commonly generated by the plant also has the primary function of photosynthesis. Biopigments undergoes a conformational change and sustain photoreduction when it absorbs a photon. In addition, the biopigments containing networks of conjugated double bond are potential for antioxidant as they can donate one or more electrons to free radicals. Here, the antioxidant activities of biopigments isolated from tropical marine diatom Navicula sp. was examined against 2,2-diphenyl-1-phycrylhydrazil (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals. The diatom Navicula sp. was cultured in the seawater medium enriched by urea, phosphate, silicate and iron; the biopigments were isolated from dried algal biomass using acetone as a solvent; test of total phenolic content performed on crude extract; biopigments purified by a silica column chromatography with n-hexane: acetone (8:2) (v/v) as solvent; the purified biopigments were characterized by Visible spectrophotometer and 2D Thin Layer Chromatography (TLC); and the antioxidant activities of biopigments was assayed against DPPH and ABTS radicals, with ascorbic acid used as a control. The cell density of Navicula sp. of 2,56 g/L was observed on the 5th day. There were 6 biopigments showing characteristics of absorption spectrum at 350–800 nm identified as β-carotene, chlorophyll a, pheophytin a, diatoxanthin, diadinoxanthin and fucoxanthin. The antioxidant activity of ascorbic acid, crude extract, pheophytin a, fucoxanthin and β-carotene against DPPH radicals assign an IC50 values of 4,9; 134,3; 27,1; 23,3 and 5,32 μg/mL respectively, whereas the antioxidant activity against ABTS radical giving IC50 values, respectively of 8,7; 107,4; 36,2; 30,6 and 5,67 μg/mL. Both crude extract and pure biopigments isolated from Navicula sp. exhibited DPPH and ABTS radical scavenging.