Total Sugar Content and Antioxidant Activity of Nipa Palm (Nypa fruticans) Fruit Husk Oligosaccharides

Abstract

Nipa palm (Nypa fruticans) is a monoecious palm widely found in Southeast Asia. The nipa palm fruit husk is a potential source of oligosaccharides that can be used as natural antioxidant agents. This study aimed to extract oligosaccharides from the nipa palm fruit husk, determine their total sugar content, and assess their antioxidant activity. The oligosaccharides were directly extracted using 80% ethanol (EtOH) or a hot water solvent (HW) and then isolated with 80% ethanol. Total sugar content was determined using the phenol-sulfuric acid method and antioxidant activity was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The results show that the yield of EtOH (12.58±3.24%) was higher than that of the HW method (7.16±1.03%). The total sugar content of the oligosaccharides was also higher in EtOH (28.84±0.43 mg Glu.eq./g dried sample) compared to the HW method (6.04±0.36 mg Glu.eq./g dried sample). Meanwhile, antioxidant activities were approximately IC50 517.93±92.49 µg/mL (EtOH) and IC50 502.66±17.35 µg/mL (HW). Based on these data, oligosaccharides extracted from nipa palm fruit husks can be used as natural antioxidant sources and formulated as ingredients in food supplements.