Free radicals quenching potential, protective properties against oxidative mediated ion toxicity and HPLC phenolic profile of a Cameroonian spice: Piper guineensis

Abstract

Considerations on antioxidants derived from plants have continuously increased during this decade because of their beneficial effects on human health. In the present study we investigated the free radical scavenging properties of extracts from Piper guineense (P. guineense) and their inhibitory potentials against oxidative mediated ion toxicity. The free radical quenching properties of the extracts against [1,1-diphenyl-2-picrylhydrazyl (DPPH•), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS•), hydroxyl radical (HO•), nitric oxide (NO•)] radical and their antioxidant potentials by FRAP and phosphomolybdenum were determined as well as their protective properties on liver enzymes. The phenolic profile was also investigated by HPLC. The results obtained, revealed that the extracts significantly inhibited the DPPH, NO, HO and ABTS radicals in a concentration depending manner. They also showed a significant ferrous ion chelating ability through FRAP and phosphomolybdenum antioxidant potential. Their polyphenol contents varied depending on the type of extracts and the solvent used. The hydroethanolic extracts (FFH) and the ethanolic extracts (FFE) of P. guineense leaves showed the higher level of phenolic compounds respectively of 21.62 ± 0.06 mg caffeic acid/g dried extract (CAE/g DE) and 19.01 ± 0.03 CAE/g DE. The HPLC phenolic compounds profile revealed a higher quantity of Eugenol, quercetin, rutin and catechin in the stem than in the leaves. The presence of these molecules could be responsible of the protective potentials of P. guineense extracts against lipid peroxidation and SOD, catalase and peroxidase. In conclusion, P. guineense extracts demonstrated significant antioxidant property and may be used as a prospective protector against metal related toxicity.

Keywords: 1,1-Diphenyl-2-picrylhydrazine (PubChem CID: 74358); 2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulphonic acid (PubChem CID: 77519615); ABTS, 2,2-azinobis(3-ethylbenzthiazoline)-6-sulphonic acid; Antioxidant; Apigenin (PubChem CID: 5280443); Ascorbic acid (PubChem CID: 54670067); BHT, butylated hydroxytoluene; Caffeic acid (PubChem CID: 689043); DPPH, 2,2-diphenyl-1-picrylhydrazyl 1,1-diphenyl-2-picrylhydrazyl radical; Eugenol; Eugenol (PubChem CID: 3314); FRAP, ferric reducing ability of plasma; FRAP, ferric reducing antioxidant power; H2O2, hydrogen peroxide; HPLC; Ion toxicity; Lipid peroxidation; MDA, malonaldialdehyde; MDA, malondialdehyde; O-coumaric acid; P-coumaric acid (PubChem CID: 637542); P. guineense; Quercetin (PubChem CID: 5280343); RNS, reactive nitrogen species; ROS, reactive oxygen species; Rutin (PubChem CID: 5280805); Syringic acid (PubChem CID: 10742); TBA, thiobarbituric acid; Theobromine (PubChem CID: 5429); Tyrosol (PubChem CID: 10393); Vit C, vitamine C.

Fig. 1

Scavenging potential of the different plant extracts: (A) DPPH•, (B) OH•, (C) NO• and (D) ABTS•. Values are expressed as mean ± SD of three replicates. In the same concentration the values affected with different letters (a–f) are significantly different at p < 0.05. FTE: P. guineense (stem) ethanolic extract; FTH: P. guineense (stem) hydroethanolic extract; FFE: P. guineense (leaves) ethanolic extract; FFH: P. guineense (leaves) hydroethanolic extract; VIT C: vitamin C.

Fig. 2

Reductive activity of the different plant extracts. Values are expressed as mean ± SD of three replicates. In the same concentration the values affected with different letters (a–f) are significantly different at p < 0.05. FTE: P. guineense (stem) ethanolic extract; FTH: P. guineense (stem) hydroethanolic extract; FFE: P. guineense (leaves) ethanolic extract; FFH: P. guineense (leaves) hydroethanolic extract; VIT C: vitamin C.

Fig. 3

FRAP and phosphomolybdenum (PAP) antioxidant activities of the different plant extracts. Values are expressed as mean ± SD of three replicates. Values are expressed as mean ± SD of three replicates. In the same concentration the values affected with different letters (a–f) are significantly different at p < 0.05. FTE: P. guineense (stem) ethanolic extract; FTH: P. guineense (stem) hydroethanolic extract; FFE: P. guineense (leaves) ethanolic extract; FFH: P. guineense (leaves) hydroethanolic extract; BHT: butylated hydroxyl toluene.

Fig. 4

Protective properties of plant extracts against lipid peroxidation. In the same concentration the values affected with different letters (a–f) are significantly different at p < 0.05. FTE: P. guineense (stem) ethanolic extract; FTH: P. guineense (stem) hydroethanolic extract; FFE: P. guineense (leaves) ethanolic extract; FFH: P. guineense (leaves) hydroethanolic extract; VIT C: vitamin C; Pos Control: oxidant (positive) control; Neg Control: normal (negative) control.

Fig. 5

Protective properties of plant extracts: SOD and peroxidase activities. Values are expressed as mean ± SD of three replicates. In the same concentration the values affected with different letters (a–f) are significantly different at p < 0.05. FTE: P. guineense (stem) ethanolic extract; FTH: P. guineense (stem) hydroethanolic extract; FFE: P. guineense (leaves) ethanolic extract; FFH: P. guineense (leaves) hydroethanolic extract; VIT C: vitamin C; Pos Control: oxidant (positive) control; Neg Control: normal (negative) control.

Fig. 6

Protective properties of plant extracts: catalase activity. Values are expressed as mean ± SD of three replicates. In the same concentration the values affected with different letters (a–f) are significantly different at p < 0.05. FTE: P. guineense (stem) ethanolic extract; FTH: P. guineense (stem) hydroethanolic extract; FFE: P. guineense (leaves) ethanolic extract; FFH: P. guineense (leaves) hydroethanolic extract; VIT C: vitamin C; Pos Control: oxidant (positive) control; Neg Control: normal (negative) control.

Fig. 7

Principal component analysis results on F1XF2 axis of antioxidant and scavenging activities of the extracts tested. In the same concentration the values affected with different letters (a–f) are significantly different at p < 0.05. Values are expressed as mean ± SD of three replicates. FTE: P. guineense (stem) ethanolic extract; FTH: P. guineense (stem) hydroethanolic extract; FFE: P. guineense (leaves) ethanolic extract; FFH: P. guineense (leaves) hydroethanolic extract; MOLYBDAT: phosphomolybdenum test; Flavonol: flavonol assay; Polyphenol: polyphenol assay; Flavonoid: flavonoid assay; NO: NO radical scavenging test; ABTS: ABTS radical scavenging test; DPPH: DPPH radical scavenging test; OH: OH radical scavenging test; RED ACT: reductive activity test.

Fig. 8

Principal component analysis results on F1XF2 axis of in vitro protective activity of P. guineense on rat liver enzymes for the tested extracts. Values are expressed as mean ± SD of three replicates. FTE: P. guineense (stem) ethanolic extract; FTH: P. guineense (stem) hydroethanolic extract; FFE: P. guineense (leaves) ethanolic extract; FFH: P. guineense (leaves) hydroethanolic extract; molybdate: phosphomolybdenum (PAP); SOD: SOD activity test; catalase: catalase activity test; peroxidase: peroxidase activity test; flavonols: flavonol assay; polyphenol: polyphenol assay; flavonoids: flavonoid assay; FRAP: FRAP antioxidant test; INHIB MDA: MDA inhibition percentage.

Fig. 9

HPLC chromatograms of phenolic extracts from P. guineense recorded at 280 nm: (A) Stem and (B) leaves (TR: 19.10: 3,4-OH-benzoic acid; 33.49: Apigenin; 25.67: Caffeic acid; 23.48: catechine; 29.43: Eugenol; 14.38; gallic acid; 25.11: O-coumaric; 21.91: OH-tyrosol; 30.52: P-coumaric acid. 42.19: quercetin; 29.45: rutin; 25.55: Syringic acid; 17.35: Theobromine; 21.77: Tyrosol and 25.27: Vanillic acid).