Sclerocarya birrea (A. Rich.) Hochst (Anacardiaceae) is a commonly used specie in African ethnomedicinal traditions. The aim of this study is to investigate: antioxidant activity of different leave (LE), root (RE) and bark (BE) extracts, and the correlation with their total phenolic content (TPC). Extracts were obtained from dried material using solvent with increasing polarity: n-hexane, CHCl3, CHC13/MeOH (9:1) and MeOH. Each extract was filtered, taken to dryness, and then used for the following assays: Folìn-Ciocalteu method was used to determinate TPC (mg of gallic acid equivaient - mgGAE); DPPH (1,1-diphenyl- 2-picrylhydrazyl radical) was used to assess radical scavenging activity (IC50); FRAP (Ferric Reducing Antioxidant Power) assay, and -Carotene bleaching (BCB) test, were used to investigate antioxidant activity and lipid peroxidation inhibition capacity respectively. All MeOH extracts demonstrated to be more active than the others (data not shown). RE showed the highest TPC and the strongest FRAP among MeOH extracts analyzed, while the lowest values were observed in LE. RE showed the highest DPPH scavenging activity while the lowest was still shown from LE. BCB results demonstrated as the highest antioxidant activity is related to BE, even if RE activity is closely related to it; on the other hand LE is nearly inactive. A significant correlation between all variables was found. In particular, a positive correlation (R2 = 0,86) between TPC and FRAP value and between TPC and IC50 (R2 = 0,82) was determined, a slightly lower correlation (R2 0,6973) between TP and %AA was also shown. Results suggest that the MeOH RE of S. birrea represents the most powerful source of natural antioxidants among analyzed extracts, and the positive correlations between TPC and biological activities, clearly indicate that phenolics are important contributors for their activities. Further investigations are needed to elucidate secondary metabolite structures, and isolate the main responsible of S. birrea MeOH extract activities.
Comparison of Total Phenolic Content, DPPH, p-Carotene, FRAP Assays of Sclerocarya birrea Extracts / Daniela, Russo; Maria Carmela, Padula; Luigi, Milella; Costantino, Valeria; Moussoukhoye Sissokho, Diop; Giuseppe, Martelli. - STAMPA. - (2011), pp. MP21-MP21. (Intervento presentato al convegno IV Scuola delle Sostanze Naturali e di Chimica Biorganica Luigi Minale tenutosi a Napoli nel 5-9 June 2011).
Comparison of Total Phenolic Content, DPPH, p-Carotene, FRAP Assays of Sclerocarya birrea Extracts
COSTANTINO, VALERIA;
2011
Abstract
Sclerocarya birrea (A. Rich.) Hochst (Anacardiaceae) is a commonly used specie in African ethnomedicinal traditions. The aim of this study is to investigate: antioxidant activity of different leave (LE), root (RE) and bark (BE) extracts, and the correlation with their total phenolic content (TPC). Extracts were obtained from dried material using solvent with increasing polarity: n-hexane, CHCl3, CHC13/MeOH (9:1) and MeOH. Each extract was filtered, taken to dryness, and then used for the following assays: Folìn-Ciocalteu method was used to determinate TPC (mg of gallic acid equivaient - mgGAE); DPPH (1,1-diphenyl- 2-picrylhydrazyl radical) was used to assess radical scavenging activity (IC50); FRAP (Ferric Reducing Antioxidant Power) assay, and -Carotene bleaching (BCB) test, were used to investigate antioxidant activity and lipid peroxidation inhibition capacity respectively. All MeOH extracts demonstrated to be more active than the others (data not shown). RE showed the highest TPC and the strongest FRAP among MeOH extracts analyzed, while the lowest values were observed in LE. RE showed the highest DPPH scavenging activity while the lowest was still shown from LE. BCB results demonstrated as the highest antioxidant activity is related to BE, even if RE activity is closely related to it; on the other hand LE is nearly inactive. A significant correlation between all variables was found. In particular, a positive correlation (R2 = 0,86) between TPC and FRAP value and between TPC and IC50 (R2 = 0,82) was determined, a slightly lower correlation (R2 0,6973) between TP and %AA was also shown. Results suggest that the MeOH RE of S. birrea represents the most powerful source of natural antioxidants among analyzed extracts, and the positive correlations between TPC and biological activities, clearly indicate that phenolics are important contributors for their activities. Further investigations are needed to elucidate secondary metabolite structures, and isolate the main responsible of S. birrea MeOH extract activities.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
