Phenolic compounds and radical scavenging potential of twenty Cameroonian spices

摘要

The antioxidant activity and phenolic content of twenty different spices commonly used inCameroon were analyzed with the view of updating our present knowledge on their nutritional andnutraceutical potentials. To achieve this aim, the ferric iron reducing activity (FIRA), hydroxylradical scavenging activity (HRSA), free radical scavenging activity (FRSA), total phenols,flavonoids, proanthocyanidins, and tannins content were analyzed using current techniques. In allthe cases significant variations (p<0.001) were observed in the levels of the parametersanalyzed. The different parameters varied as follows: total phenols (1.05 – 38.80 g/100 g),flavonoids (0.00 g – 5.94 g/100 g), tannins (0.00 – 281.5 mg/100 g), FIRA (1.55 – 168.63 mg/100g), FRSA (3.96 – 71.5 mg/g), HRSA (0.01 – 2.45 mg/100 g). Using Principal Component Analysis(PCA), 79 % of the variation in spices was found to be mainly associated with their FRSA, FIRA,total phenols, flavonoids, and proanthocyanidins content. Furthermore, using K-meansclassification, it was possible to classify the spices into four major groups, each of relativelysimilar composition as follows: Group 1 has high FRSA and FIRA levels, high phenols, andflavonoids contents: Dichrostachys glomerata, Fagara leprieuri; Group 2 has high HRSA levels:Fagara xanthoxylo?des, Mondia whitei, Pentadiplandra brazzeana, Piper guineense,Scorodophleus zenkeri (fruit), Scorodophleus zenkeri (bark); Group 3 has low levels in allvariables: Aframomum daniellii, Hua gabonii (fruit), Monodora myristica, Dorstenia psilurus, Huagabonii (bark), Piper umbellatum, Solanum melongena, Scleria striatinux, Xylopia aethiopica andGroup 4 has moderate levels of FRSA and FIRA, phenols, flavonoids and proanthocyanidins:Echinops giganteus and Tetrapleura tetraptera. In addition Pearson correlation analysis revealedstrong positive correlations between FRSA and FIRA (93 %), between FRSA and total phenols(90 %) and between flavonoids and total phenols (93 %). Dichrostachys glomerata and Fagaraleprieuri were the spices with the best antioxidant activity and highest phenolic content.