Antioxidant properties of ginger (Kaempferia angustifolia Rosc.) and its chemical markers

Figures & data

Figure 1. Chemical constituents obtained from Kaempferia angustifolia: boesenboxide (1), crotepoxide (2), 2ˊ-hydroxy-4,4ˊ,6ˊ-trimethoxychalcone (3), kaempfolienol (4), and zeylenol (5).

Table 1. Antioxidant activity of Kaempferia angustifolia (rhizomes) and its phytochemicals.

Extract/pure compound	DPPH (mg TE/g of extract or compound)	ABTS (mg TE/g of extract or compound)	CUPRAC (mg TE/g of extract of compound)	FRAP (mg TE/g of extract or compound)
Hexane	333 ± 10	8.0 ± 0.1	901 ± 72	206 ± 13
Chloroform	616 ± 17	27.7 ± 0.1	760 ± 16	310 ± 15
Ethyl acetate	588 ± 13	23.3 ± 0.2	844 ± 56	342 ± 41
Methanol	616 ± 13	39 ± 2	848 ± 10	224 ± 25
Boesenboxide (1)	141 ± 18	36.7 ± 0.7	1094 ± 10	149 ± 5
Crotepoxide (2)	192 ± 23	41.5 ± 0.1	1087 ± 0	242 ± 18
2ˊ-hydroxy-4,4ˊ,6ˊ-trimethoxychalcone (3)	311 ± 5	42.2 ± 0.2	1497 ± 88	782 ± 55
Kaempfolienol (4)	444 ± 10	28.0 ± 0.6	1145 ± 3	100 ± 1
Zeylenol (5)	237 ± 10	26.5 ± 0.6	1069 ± 33	89 ± 4

The values are expressed as mean ± standard deviation of duplicates.

Figure 2. The proposed chemical reaction of 2ˊ-hydroxy-4,4ˊ,6ˊ-trimethoxychalcone (3) in antioxidant assays: DPPH (A), ABTS (B), CUPRAC (C), and FRAP (D) assays via SET mechanism.

Figure 3. The proposed chemical reaction of 2ˊ-hydroxy-4,4ˊ,6ˊ-trimethoxychalcone (3) in antioxidant assays: DPPH (A) and ABTS (B) assays via HAT mechanism.

Figure 4. The proposed chemical reaction of kaempfolienol (4) in antioxidant assay DPPH via HAT mechanism.

Figure 5. The proposed chemical reaction of boesenboxide (1) in antioxidant assays: DPPH (A), ABTS (B), and FRAP (C) via SET mechanism.

Figure 6. The proposed chemical reaction of crotepoxide (2) in antioxidant assays: DPPH (A), ABTS (B), and FRAP (C) via SET mechanism.

Figure 7. The proposed chemical reaction of boesenboxide (1) (A) and crotepoxide (2) (B) in antioxidant assay CUPRAC via SET mechanism.

Figure 8. The proposed chemical reaction of zeylenol (5) in antioxidant assay DPPH via HAT mechanism.