Antioxidant Activity, Total Phenolic and Total Flavonoid Contents of Etlingera elatior (Jack) R.M. Smith from North Luwu, Indonesia

Etlingera elatior (Jack) R.M. Smith is an endemic plant of North Luwu, Indonesia. It is used traditionally as acidifiers in food. This study aim to evaluate the antioxidant activity, total phenolic and total flavonoid contents of the ethanol leaf extract of E. elatior. The dried leaves of E. elatior were extracted by maceration in 70% ethanol at room temperature for three days. The antioxidant activity of the extract was assessed using the 2,2-diphenyl-1-picrilhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assays and ferric reducing antioxidant power (FRAP) method. The total phenolic and total flavonoid contents were determined using the Folin-Ciocalteu and Aluminium chloride colorimetric methods. The results showed that E. elatior leaf extract had antioxidant activity with IC50 value of 42.45 ± 1.37 µg/mL compared to 2.78 ± 0.01 µg/mL for vitamin C (Positive control) for DPPH radical scavenging activity. While for the ABTS scavenging activity, the IC50 was 26.46 ± 0.09 µg/mL compared to 0.15 ± 0.02 µg/mL for vitamin C. In the FRAP assay, the extract showed a ferric reducing antioxidant power of 78.52 ± 0.26 mgAAE/g extract. The total phenolic and total flavonoid contents of the extract were 27.19 ± 0,07 mgGAE/g extract and 4,60 ± 0,01 mgQE/g extract, respectively. From the results of the study, it can be concluded that the ethanol leaf extract of E. elatior has strong antioxidant activity which could be attributed to its high phenolic and flavonoid contents.