Valorization of Algerian Saffron: Stigmas and Flowers as Source of Bioactive Compounds

Purpose: Saffron is widely used for its medicinal and culinary properties. Its stigmas are the most expensive part comparing with the flowers that are discarded during production. For that, the objective of this work was to determine the phytocomplex of stigma and flower material (except stigma) of saffron from Algeria. Crocin, picrocrocin and safranal contents were quantified to classify its quality according to ISO/TS 3632 standards. The antioxidant and antimicrobial properties of extracts were also investigated. Methods: Crocins, total phenolic content, flavonoids, phenolic acids, and anthocyanins were detected and quantified by HPLC-DAD and spectrophotometric analyses. The antioxidant potential was evaluated by 4 in vitro assays. The antimicrobial activity against seven bacteria and two strains of Candida albicans was also evaluated. Results: The results revealed that the chromatographic analysis showed the presence of 20 phenolic acids and flavonoids in the plant samples, with the highest concentrations in stigmas. Crocin derivatives were found only in stigmas, except that trans-crocetin (β-D-gentiobiosyl) which was present also in flower material. The highest total phenolic, total flavonoid and total flavonol contents were observed in stigmas and the highest level of anthocyanins and hydrolysable and condensed tannins in flowers. This extract showed a stronger protection effect from β-carotene bleaching and a higher TAC. The both extracts had some antimicrobial effect. Conclusions: These results point out that flower material could be considered as natural bioresource of polyphenolic compounds, with higher biological activities which remain to be exploited. Graphic Abstract: [Figure not available: see fulltext.]