Chemical characterization of Eryngium foetidum L. leaves in relation to the pruning of floral stalks and harvest time

Eryngium foetidum L. is an aromatic vegetable used as seasoning and medicinal plant, in the treatment of fever, colds, pains and other diseases, being a source of flavonoids, saponins and essential oil. It has anti-inflammatory and analgesic activity, confirming the indications for traditional use. The pruning of floral stalks is recommended to increase the productivity of the herb, though it is unclear whether this practice may affect leaf quality. As well, information about the optimal time for harvest is not available. The present study was aimed to evaluate the quality of E. foetidum leaves in relation to the pruning of floral stalks and harvest time. The study was carried out in Botucatu-SP, Brazil, following a randomly block design, in factorial scheme 2x5. Intact plants and plants with floral stalks pruned weekly were grown in greenhouse and harvested in 5 different times (at 30th, 60th, 90th, 120th and 150th days after transplanting). Chlorophyll a, chlorophyll b, carotenoids, anthocyanins, flavonoids, total polyphenols and the enzyme activity of peroxidase and polyphenoloxidase were evaluated. The leaves harvested at 60th day showed the highest amounts of chlorophyll a, chlorophyll b and carotenoids, where the amount of anthocyanins in leaves was higher at 30th, 60th and 150th days. Leaves harvested at 30th day showed the highest amounts of polyphenols and flavonoids. The enzymes peroxidase and polyphenoloxidase showed the lowest activity at 60th day. An increasing in the activity of these enzymes, starting from 90th day was observed. The pruning of floral stalks does not affect the quality of E. foetidum leaves. We suggest carrying out leaf harvesting at 60th day after transplanting.