Phenolic profile, antioxidant and anti-inflammatory potential of herb and root extracts of seven selected legumes

• Detailed phenolic profile of seven legumes' herb and root extracts.
• High levels of isoflavones genistein and daidzein in the all examined species.
• Good FRAP reducing power and moderate ability to scavenge DPPH and NO radicals.
• Low anti-inflammatory activity of the examined extracts.

Herb and root parts of legumes are not commonly used in human consumption, since they are traditionally considered waste material. Although inedible, these plant parts have a complex chemical composition, with potential biological activities. They are especially rich in polyphenols, such as flavonoids, isoflavonoids and phenolic acids. In this paper, phenolic profile of the seven selected legumes (soybean (Glycine max L.), common bean (Phaseolus vulgaris L.), pea (Pisum sativum L.), broad bean (Vicia faba L.), chickpea (Cicer arietinum L.), white lupin (Lupinus albus L.) and grass pea (Lathyrus sativus L.)) was examined using LC–MS/MS method. In the examined herb and root extracts 33 phenolic compounds were identified and quantified. High levels of isoflavones genistein and daidzein were found in G. max, P. vulgaris and L. albus root extracts (1.02–1.53, 0.309–0.648 and 2.81 mg/g, respectively). C. arietinum, L. albus and P. vulgaris herb extracts were found to be the richest sources of flavonoid compounds (13.1–19.4, 5.98 and 2.36–3.64 mg/g, respectively). Since polyphenols have redox properties, antioxidant activity of the abovementioned plants was investigated using DPPH, NO, and FRAP assay. All samples demonstrated the ability to scavenge both DPPH and NO radical, and exhibited a good FRAP reducing power. V. faba exhibited the highest antioxidant activity (DPPH IC50 11.7–20.7 μg/mL, NOIC30 0.080–0.34 mg/mL, FRAP 32.6–66.9 AAE/g dw). Anti-inflammatory potential was examined using in vitroCOX-1/12-LOX pathway inhibition assay, resulting in moderate activity of all samples (IC50 2.09–8.00 for all metabolites). The obtained results indicate a strong potential of waste legume material as a promising source for isolation of bioactive antioxidant and anti-inflammatory compounds for their use as therapeutic and dietary supplements in pharmaceutical and food industry.