Phenolic Composition and Phytochemical Analysis of Moroccan Raw and Processed <i>Capparis spinosa</i> Buds and Berries

Abstract

Capparis spinosa, also known as spiny caper, is a widely distributed plant in Mediterranean regions, valued for its nutritional and medicinal properties. Its richness in bioactive compounds, particularly polyphenols, makes it a subject of interest for various therapeutic applications. This study aims to characterize the phenolic compounds present in raw and processed caper buds and berries and evaluate their antioxidant potential. The identification of phenolic compounds, performed by ultra-high-performance liquid chromatography coupled with mass spectrometry, revealed the presence of flavonoids, mainly flavonols (rutin, quercetin, kaempferol, myricetin, and isorhamnetin), as well as phenolic acids such as sinapic acid, para-coumaric acid, ferulic acid, and vanillic acid. The results of the spectrophotometric quantification of total polyphenols and total flavonoids showed that raw capers contain the highest concentrations of polyphenols and flavonoids, with values ranging between 86.19 mg gallic acid equivalent/g DW and 31.29 mg quercetin equivalent/g DW, respectively. Fermented caperberries present the lowest concentrations. The evaluation of the antioxidant potential, performed by in vitro 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power tests, demonstrated strong antioxidant activity in different extracts, particularly in raw capers, which is correlated with their high content of phenolic compounds. These findings highlight the potential of Moroccan C. spinosa as a natural source of antioxidants, with possible applications in the development of functional foods, nutraceuticals, and natural health products.