Antioxidant and cytotoxic activity of polyphenolic compounds isolated from the leaves of Leucenia leucocephala

Figures & data

Figure 1.  Flow chart of fractionation, extraction and purification of polyphenolic compounds isolated from the leaves of L. leucocephala.

Figure 2.  Structures of compounds isolated from the leaves of L. leucocephala.

Table 1.  DPPH radical scavenging activity, TPC, TF and MeOH, EtOAc and n-BuOH extracts of leaves of L. leucopholea.

Extract	DPPH SC50 (µg/ml)	TPC (mg GAE/g ext)	TF (mg RE/g)	Total antioxidant (mg AAE/g ext.)
80% MeOH	*3.94 ± 0.34	220.7 ± 3.1	63.15 ± 2.1	677.98 ± 3.70
EtOAc	*4.41 ± 0.27	200.49 ± 2.87	101.33 ± 10.06	600.34 ± 4.72
n-BuOH	*7.16 ± 0.31	145.35 ± 2.17	53.33 ± 8.32	550.66 ± 7.64
Ascorbic acid	7.90 ± 0.20	—	—	—

Results are means ± SD (n = 3).

GAE, gallic acid equivalent; RE, rutin equivalent; AAE, ascorbic acid equivalent; TPC, total phenolic content; TF, total flavonoid content.

*Significant differences vs. standard P < 0.05.

Table 2.  DPPH radical scavenging activity and total antioxidant capacity of compounds (4–8) isolated from 80% MeOH leaf extract of L. leucopholea.

Compound	DPPH SC50 (µg/ml)	Total antioxidant capacity (mg AAE/g compound)
7	2.49 ± 0.57*	665.62 ± 5.10
8	5.08 ± 0.23*	491.13 ± 3.63
4	7.16 ± 0.31*	470.86 ± 4.85
5	14.03 ± 0.37	227.6 ± 5.55
6	68.75 ± 1.5	71.3 ± 4.8
Ascorbic acid	7.90 ± 0.20	—

Results are means ± SD (n = 3).

AAE, ascorbic acid equivalent.

*Significant differences vs. standard P < 0.05.

Figure 3.  Correlation of DPPH radical scavenging activity of 80% methanol, ethyl acetate and n-butanol extracts of leaves of L. leucocephala to their phenolic contents.

Figure 4.  Correlation of antioxidant activity of 80% methanol, ethyl acetate and n-butanol extracts of the leaves of L. leucocephala to their phenolic contents.

Figure 5.  Reducing power of 80% methanol, ethyl acetate and n-butanol extracts of the leaves of L. leucocephala relative to ascorbic acid (n = 3).

Figure 6.  Reducing power of the isolated compounds (4–8) from the methanol leaf extract of L. leucocephala relative to ascorbic acid (n = 3).

Table 3.  Cytotoxic activity of 80% methanol extract and compounds 7 and 8 of L. leucocephala against Hep G2 cell line.

Concentration (µg/ml)	Survival fraction
	80% MeOH extract	Compound 7	Compound 8
0.00	1.00 ± 0.00	1.00 ± 0.00	1.00 ± 0.00
1.00	0.556 ± 0.05	0.623 ± 0.06	0.634 ± 0.06
2.50	0.446 ± 0.04	0.474 ± 0.04	0.521 ± 0.05
5.00	0.373 ± 0.03	0.381 ± 0.04	0.390 ± 0.05
10.00	0.241 ± 0.02	0.304 ± 0.03	0.376 ± 0.04

Results are means ± SD of 24, 48 and 72 treatment periods (n = 3).

Table 4.  IC₅₀ of 80% methanol extract, compounds 7 and 8 of L. leucocephala against Hep G2 cell line.

Sample	IC50 µg/ml
80% MeOH extract	1.41 ± 0.17
Compound 7	2.14 ± 0.26
Compound 8	2.81 ± 0.35

Results are means ± SD (n = 3).

Figure 7.  Cytotoxic activity of 80% methanol extract, compound 7 and compound 8 of L. leucocephala against Hep G2 cell line (n = 3).