Antioxidant Activity of Different Extracts of Red Pitaya (Hylocereus polyrhizus) Seed

Figures & data

Table 1 Extraction and percent yield of the red pitaya seed extracts using different solvents

Extract	Extraction yield ^a (g)	Yield ^b (%)
Ethanol	3.08 ± 0.51	15.4^c
Chloroform	6.99 ± 0.51	34.9^d
Hexane	5.38 ± 0.34	26.9^e
^aEach value is expressed as means ± SD of three independent extractions (n = 3).
^bMeans with different letters^(c,d,e) within a column are significantly different (P < 0.05) as determined by Tukey's multiple range test.

Figure 1 The antioxidant activity of the red pitaya seed extracts as measured by DPPH^• assay.

Figure 2 The antioxidant activity of the red pitaya seed extracts as measured by linoleic acid model system.

Figure 3 The antioxidant activity of the red pitaya seed extracts as measured by FTC method.

Table 2 Total phenolic and ascorbic acid contents of the red pitaya seed

mg/g DW^a seed
Total phenolic^b	Ascorbic acid
13.56 ± 2.04	0.36 ± 0.01
^aDW, dry weight.
^bExpressed as gallic acid equivalent (GAE).
Each value is expressed as means ± SD of three independent samples with three measurements per sample (n = 9).

Figure 4 HPLC chromatograms of (a) a mixture of flavonoid standard; (b) red pitaya seed [absorbance at 280 nm vs. time (min)]: catechin (1), epicatechin (2), rutin (3), quercetin (4), myricetin (5), and kaempferol (6).

Table 3 Flavonoids content of the red pitaya seed

mg/g DW^a
Catechin	Epicatechin	Rutin	Quercetin	Myricetin	Kaempferol
3.60 ± 2.33	0.60 ± 0.11	0.53 ± 0.02	1.31 ± 0.45	0.63 ± 0.30	ND^b
^aDry weight.
^bNot detected (below detection limit).
Each value is expressed as means ± SD of three independent samples with three measurements per sample (n = 9).