Effects of Methods and Durations of Extraction on Total Flavonoid and Phenolic Contents and Antioxidant Activity of Java Cardamom (Amomum compactum Soland Ex Maton) Fruit

Abstract

Free radicals contribute to the pathophysiology of degenerative diseases which increase mortality globally, including mortality in Indonesia. Amomum compactum Soland. Ex Maton fruit from the Zingiberaceae family, also known as Java cardamom, contains secondary metabolites that have high antioxidant activities. The antioxidant activity of the methanol extract of Java cardamom fruit correlates with its flavonoid and phenolic compound contents, which can be affected by different methods and durations of extraction. This study aimed to measure and compare the effects of extraction methods and durations on total flavonoid and phenolic contents (TFCs and TPCs) and subsequent antioxidant activities by the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical, ferric reducing antioxidant power (FRAP), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS), and cupric ion reducing antioxidant capacity (CUPRAC) assays. Methanol extracts of Java cardamom were produced by continuous shaking (CSE), microwave-assisted (MAE), or ultrasonic-assisted extractions (UAE) for three different durations. CSE for 360 min resulted in the highest TFCs (3.202 mg Quercetin Equivalent/g dry weight), while the highest TPCs (1.263 mg Gallic Acid Equivalent/g dry weight) were obtained by MAE for 3 min. Out of the investigated methods, MAE for 3 min resulted in the highest antioxidant activity results for the extracts. We conclude that the polyphenolic antioxidant yield of Java cardamom depends on two parameters: the method and the duration of extraction.

Keywords: Java cardamom fruit; antioxidants; extraction methods; total flavonoid content; total phenolic content.

Figure 1

Scatter plot displaying Pearson’s correlations between antioxidant activities and (a) total flavonoid contents (TFCs) and (b) total phenolic contents (TPCs) of the methanol extracts of A. compactum that were generated by microwave-assisted extraction (MAE). The antioxidant activities of the extracts were measured by four independent assays. ABTS, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate); CUPRAC, cupric ion reducing antioxidant capacity; DPPH, 2,2′-diphenyl-1-picrylhydrazyl; DW, dry weight; FRAP, ferric reducing antioxidant power; GAE, gallic acid equivalent; QE, quercetin equivalent; TE, Trolox equivalent.

Figure 2

Scatter plot displaying Pearson’s correlations between antioxidant activities and (a) total flavonoid contents (TFCs) and (b) total phenolic contents (TPCs) of methanol extracts of A. compactum that were generated by continuous shaking extraction (CSE). The antioxidant activities of the extracts were measured by four independent assays. ABTS, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate); CUPRAC, cupric ion reducing antioxidant capacity; DPPH, 2,2′-diphenyl-1-picrylhydrazyl; DW, dry weight; FRAP, ferric reducing antioxidant power; GAE, gallic acid equivalent; QE, quercetin equivalent; TE, Trolox equivalent.

Figure 3

Scatter plot displaying Pearson’s correlations between antioxidant activities and (a) total flavonoid contents (TFCs) and (b) total phenolic contents (TPCs) of methanol extracts of A. compactum that were generated by ultrasonic-assisted extraction (UAE). The antioxidant activities of the extracts were measured by four independent assays. ABTS, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate); CUPRAC, cupric ion reducing antioxidant capacity; DPPH, 2,2′-diphenyl-1-picrylhydrazyl; DW, dry weight; FRAP, ferric reducing antioxidant power; GAE, gallic acid equivalent; QE, quercetin equivalent; TE, Trolox equivalent.