Abstract
Vicia faba L. is a widely cultivated legume known to contain numerous specialised metabolites. In this study, the seed coats and cotyledons of two ancient V. faba L. varieties, historically consumed in southern Italy and distinguished by black and purple seed coats, were extracted using 80% methanol and 80% ethanol. Extracts were analysed for total polyphenol, flavonoid and proanthocyanidin contents, and antioxidant activity using DPPH, ABTS, and FRAP assays. The purple seed coats exhibited the highest levels of phenolics and antioxidant capacity, exceeding those of black seed coats. Next, liquid chromatography coupled with high-resolution mass spectrometry (LC-ESI-HR-MS) was used to characterise the bioactive metabolites in both seed coats and cotyledons. The purple variety showed a higher phytochemical content, with a greater level of flavonoids and proanthocyanidins in methanolic extract. Furthermore, the purple seed coat exhibited in vitro anti-inflammatory activity by inhibiting soluble epoxide hydrolase (sEH), a key enzyme in the arachidonic acid cascade, with an IC50 of 31.51 ± 1.16 µg/µL. Elemental analysis was performed for both varieties to assess their nutritional value. Specifically, the purple seed coats were found to represent a valuable source of bioactive compounds and micronutrients, highlighting their potential applications in nutraceutical, cosmetic, and food supplement sectors.
Introduction
Vicia faba L., commonly known as broad bean or fava bean (Fabaceae family), originates from the Near East and is recognised by the Food and Agriculture Organisation (FAO) as one of the most widely cultivated edible legumes as human food in developing countries. Compared to wheat monoculture, faba bean cultivation reduces greenhouse gas emissions and increases soil nitrogen fixation. This legume can grow without irrigation, particularly in regions with cold, rainy seasons. Thanks to its adaptability across different soil types, it is one of the most resilient crops in the face of global warming and climate change.
Edible seeds of V. faba are widely grown and consumed across Europe, the Middle East, East Asia, Australia, and parts of Latin America and Africa, either in dry or fresh form. These seeds are rich in dietary fibre, carbohydrates, vitamins, and essential minerals such as iron and zinc, and they contain both saturated and unsaturated fatty acids, which contribute to their high nutritional value.
Moreover, V. faba is an excellent source of essential amino acids and proteins, making it a suitable substitute for soya flour in vegetarian diets and a cost-effective feed additive for livestock.
In addition to their macronutrient value, broad beans contain choline, lecithin, various phenolic compounds, phytosterols, and other secondary metabolites with antioxidant, enzyme-inhibitory, antibacterial, and neuroactive properties. Moreover, due to their low glycaemic index, broad beans can help control blood sugar levels and reduce the risk of developing diabetes.
Further nutritional and functional properties of faba beans are associated with their content of bioactive peptides, prebiotic-functioning raffinose family oligosaccharides, and 3,4-dihydroxy-L-phenylalanine (L-DOPA or levodopa), which plays a crucial role in the central nervous system. These features make V. faba a promising subject for phytochemical and nutraceutical studies.
However, its nutritional benefits are partly offset by the presence of anti-nutrient factors such as trypsin inhibitors, condensed tannins, lectins, phytic acid, vicine and convicine.
Vicine and convicine occur in dried and dehulled V. faba beans at levels of 0.73% and 0.30% by weight, respectively. These compounds undergo hydrolysis through the cleavage of their β-glycosidic bonds, yielding the corresponding aglycones: divicine (2,6-diamino-4,5-hydroxypyramidine) from vicine, and isouramil (6-amino-2,4,5-trihydroxypyramidine) from convicine. The reaction is triggered by the presence of β-glucosidase during seed development, or by microbial β-glucosidase during consumption and digestion in the large intestine and caecum.
These aglycones can trigger favism, a potentially severe haemolytic anaemia in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency, which is common in populations of the Middle East and the Mediterranean basin. Consequently, their utilisation for farmed animals and birds is precluded, unless they are subjected to a special preparation aimed at eliminating or reducing potential undesirable effects.
To mitigate these risks, special processing or breeding strategies have been employed, and several cultivars with low vicine/convicine content have been developed. Moreover, dehulling and other treatments have been investigated to assess their impact on the nutritional and bioactive properties of broad beans.
The present study aims to investigate the phytochemical composition and biological activity of two ancient varieties of coloured broad beans traditionally consumed in southern Italy. Ancient varieties, traditionally cultivated in specific regions and generally not intended for large-scale commercial production, have attracted increasing interest due to their potential richness in bioactive compounds with recognised health-promoting properties.
Specifically, the composition of two ancient Vicia faba L. varieties—one with black (VFB, See Supporting Information Figure S1) and one with purple (VFP, See Supporting Information Figure S1) seed coats—was analysed, examining seed coats and cotyledons separately. This study aims to provide insight into the potential value of these ancient varieties and to evaluate their suitability for possible applications in the nutraceutical, cosmetic, and dietary supplement sectors.
A multi-analytical approach was applied to investigate the chemical composition, bioactivity, and nutraceutical value of black and purple Vicia faba seeds. Spectrophotometric assays were first used to evaluate total phenolic content and antioxidant activity, followed by LC-MS-based metabolite profiling to characterise the main classes of bioactive compounds. Based on this profiling, proanthocyanidins were selected for targeted quantitative analysis. The biological relevance of the extracts was further assessed through anti-inflammatory assays, supported by molecular docking analysis, while mineral profiling was performed to provide additional insight into the nutraceutical properties of seed coats and cotyledons.
Conclusions
The study highlights that, in the two analysed Vicia faba varieties with coloured seed coats, differences in seed coat pigmentation are associated with distinct phenolic profiles, antioxidant activities, and elemental distributions. The purple seed coats stand out as the richest source of bioactive compounds, displaying the highest total phenolic, flavonoid, and proanthocyanidin contents, which directly correlate with their enhanced antioxidant capacity.
The combined use of ethanol and methanol extraction provided essential insights into the chemical diversity of these beans. Ethanol, as a greener solvent, yielded a broad and representative extract across compound classes, supporting its use in sustainable metabolite screening. However, methanol extraction proved more efficient for recovering flavonoids and proanthocyanidins, and its use remains preferable when these target compounds are of specific interest. LC–ESI–HR–MS analysis allowed the putative identification of several metabolites, including polar lipids not previously reported in this species, representing a novel contribution to the phytochemical knowledge of V. faba.
The purple variety also showed promising anti-inflammatory activity by inhibiting in vitro key enzymes involved in inflammation, particularly the methanol extract, suggesting potential application in the development of functional foods or nutraceuticals with anti-inflammatory properties. Overall, this work provides new insight into the chemical and biological properties of pigmented V. faba seeds and establishes a foundation for future studies on their health-promoting potential, breeding programmes, and valorisation in nutraceutical formulations.
Download the full research article as PDF: Potential Nutraceutical Properties of Vicia faba L
or read the full article here.
Fantasma, F.; D’Urso, G.; Capuano, A.; Colarusso, E.; Aliberti, M.; Grassi, F.; Brunese, M.C.; Saviano, G.; De Felice, V.; Lauro, G.; et al. Potential Nutraceutical Properties of Vicia faba L: LC-ESI-HR-MS/MS-Based Profiling of Ancient Faba Bean Varieties and Their Biological Activity. Molecules 2026, 31, 184. https://doi.org/10.3390/molecules31010184
