Characterization of Ingredients Incorporated in the Traditional Mixed-Salad of the Capuchin Monks

Abstract

Recipes on the composition of the "salad of the monks" (Capuchin monks) have been reported in Italy since the 17th century. Different wild edible plants were highly regarded as an important ingredient of this mixed salad. Among these, some species played a key role for both their taste and nutritional properties: Plantago coronopus L. (PC), Rumex acetosa L., Cichorium intybus L., and Artemisia dracunculus L. In the present study, the micromorphological and phytochemical features as well as the antioxidant and anti-inflammatory properties of extracts of these fresh and blanched leaves, were investigated. The extracts obtained by blanched leaves, according to the traditionally used cooking method, showed the highest content of bioactive compounds (total phenols 1202.31-10,751.88 mg GAE/100 g DW; flavonoids 2921.38-61,141.83 mg QE/100 g DW; flavanols 17.47-685.52 mg CE/100 g DW; proanthocyanidins 2.83-16.33 mg CyE/100 g DW; total chlorophyll 0.84-1.09 mg/g FW; carbohydrates 0.14-1.92 g/100 g FW) and possess the most marked antioxidant (IC₅₀ 0.30-425.20 µg/mL) and anti-inflammatory activity (IC₅₀ 240.20-970.02 µg/mL). Considering this, our results indicate that increased consumption of the investigated plants, in particular of PC, raw or cooked briefly, could provide a healthy food source in the modern diet by the recovery and enhancement of ancient ingredients.

Keywords: Artemisia dracunculus L.; Cichorium intybus L.; Plantago coronopus L.; Rumex acetosa L.; anti-inflammatory properties; antioxidant activity; edible wild plants; human diet; phytochemistry.

Figure 1

Representative pictures of the four selected plant species: (a) Plantago coronopus L.; (b) Rumex acetosa L.; (c) Cichorium intybus L.; (d) Artemisia dracunculus L.

Figure 2

Scanning electron microscopic view of leaves from PC (a–c) and RA (d–f). (a) Abaxial surface showing epidermal cells, trichomes and stomata; (b) abaxial surface showing a non-glandular multicellular trichome (MT) on the leaf midrib; (c) adaxial surface showing two types of non-glandular trichomes: bottle-like trichomes (BT) and long stalked MT; (d) on the adaxial surface are visible anisocytic and paracytic stomata, and peltate glandular trichomes (the arrow points an abnormal glandular trichome); (e) abaxial surface with glandular trichomes and anisocytic and paracytic stomata; (f) close-up view of a peltate glandular trichome on the adaxial surface.

Figure 3

Scanning electron microscopic view of leaves from CI (a–c) and AD (d–f). (a) Adaxial surface showing a non-glandular multiseriate trichome on the leaf margin; (b) adaxial surface showing another type of non-glandular multiseriate trichome and characteristic undulating epidermal cell walls; (c) abaxial surface showing multiseriate glandular trichomes along the midrib; (d) abaxial surface showing stellate non-glandular trichomes and biseriate glandular trichomes (arrow); (e) close-up view of a stellate non-glandular trichome; (f) close-up view of a biseriate glandular trichome.

Figure 4

Antioxidant and free radical-scavenging activity of fresh (F) and cooked (C) leaf extracts of the traditional wild salad of the Capuchin monks: Plantago coronopus L. (PC), Rumex acetosa L. (RC), Cichorium intybus L. (CI), and Artemisia dracunculus L. (AD). Results were expressed as mean inhibition percentage (%) ± standard deviation of three independent experiments (n = 3). (a) FRAP, concentration ranges (I–III): 12.5–50.0 μg/mL for PCC; 150.0–600.0 μg/mL for PCF, RAC, CIC, ADF and ADC; 300.0–1200.0 μg/mL for CIF; 600–2400.0 μg/mL for RAF; (b) TEAC, concentration ranges (I-III): 12.5–50.0 μg/mL for PCC; 80.0–320.0 μg/mL for PCF; 150.0–600.0 μg/mL for ADC, ADF, CIC and RAC; 300.0–1200.0 μg/mL CIF and RAF; (c) Ferrozine, concentration ranges (I–III): 3.0–12.0 μg/mL for PCF, RAF, RAC, CIF, CIC, ADF and ADC; 12.0–48.0 μg/mL for PCC; (d) ORAC, concentration ranges (I–III): 0.12–0.50 μg/mL for PCC; 0.5–4.0 μg/mL for PCF, CIF, CIC, ADF, ADC and RAC; 1.5–12.0 μg/mL for RAF. * p < 0.05 vs. fresh extract; ^§ p < 0.05 vs. PCF or PCC; ° p < 0.05 vs. ADF or ADC; ^$ p < 0.05 vs. CIF or CIC.

Figure 5

Anti-inflammatory activity of fresh (F) and cooked (C) leaf extracts of the traditional wild salad of the Capuchin monks: Plantago coronopus L. (PC), Rumex acetosa L. (RC), Cichorium intybus L. (CI), and Artemisia dracunculus L. (AD) towards BSA denaturation assay (a) and protease inhibition assay (b). Results were expressed as mean inhibition percentage (%) ± standard deviation of three independent experiments (n = 3). * p < 0.05 vs. fresh extract; ^§ p < 0.05 vs. PCF or PCC; ° p < 0.05 vs. ADF or ADC; ^$ p < 0.05 vs. CIF or CIC.

Figure 6

(a,b) San Barnaba Convent vegetable garden and greenhouses (Genova, Italy); (c) plants collected after 60 days for carrying out laboratory analyses.