Conventional, organic and biodynamic farming: differences in polyphenol content and antioxidant activity of Batavia lettuce.

BACKGROUND: Lactuca sativa L. ssp. acephala L., cv. Batavia red Mohican plants were cultivated under intensive conventional, organic and biodynamic farming and were analyzed for their polyphenol content and antiradical activity in order to demonstrate the influence of farming on yield, polyphenol content and antiradical activity. RESULTS: The yield of plants from conventional farming was the highest (2.89 kg m⁻²), while polyphenol content, measured by spectrophotometry, of these plants was lower at P < 0.05 (1.36 mg g⁻¹) than the content of plants from organic and biodynamic farming (1.74 and 1.85 mg g⁻¹, respectively). The antiradical activity, measured by DPPH · assay, was positively correlated to flavonoid and hydroxycinnamic acid contents. CONCLUSION: Flavonoid, hydroxycinnamic acid and anthocyan patterns were not affected by the type of cultivation, while quantitative differences were demonstrated and some differences were found between conventional farming and organic or biodynamic farming. The yield of conventionally grown salads was the highest.

Polyphenol content of modern and old varieties of Triticum aestivum L. and T. durum Desf. grains in two years of production.

Antiradical activity and total polyphenol and flavonoid contents of modern and old varieties of durum (9 varieties) and soft (17 varieties) wheat grains, sampled over two years (summer 2007 and 2008) in the same site, were determined in order to point out differences among varieties and between old and modern varieties. Nine compounds were identified by means of HPLC/MS, and their amount was determined. No correlation was found between antiradical activity and polyphenol or flavonoid contents. The temperature conditions in the 30 days before harvesting were the principal factor which differentiated the quantitative profile of polyphenols and the antiradical activity of the seeds (p < 0.001): high temperatures cause a drop in polyphenol content.

Polyphenol content and antioxidative activity in some species of freshly consumed salads.

Ten genotypes belonging to Lactuca sativa, Cicorium intybus, Plantago coronopus, Eruca sativa, and Diplotaxis tenuifolia and used in fresh mixed salads were investigated for their polyphenol contents. Flavonoids and hydroxycinnamic acids were characterized by high-performance liquid chromatography (HPLC)/diode array detection/mass spectrometry. Quercetin, kaempferol, luteolin, apigenin, and crysoeriol derivatives were identified; hydroxycinnamic acids were all caffeoyl derivatives. The total polyphenol content was obtained through the Folin-Ciocalteu test and from the HPLC data. The amounts ranged between 0.9 and 4.7 mg/g fresh weight. The antiradical activity was determined by the reaction with the stable DPPH* radical. The Fe2+ chelating activity was determined with a spectrophotometric test. From the complex of data, a quite complete picture of the characteristics of the vegetables emerges. A cultivated C. intybus cultivar exhibited the highest polyphenol content, while a wild C. intybus genotype exhibited the highest antiradical activity. In every case, the characteristics of the different salads as functional foods have been pointed out.

HPLC-DAD/MS characterization of flavonoids and hydroxycinnamic derivatives in turnip tops (Brassica rapa L. Subsp. sylvestris L.).

Flavonoids and hydroxycinnamic derivatives of turnip tops (Brassica rapa L. subsp. sylvestris L.) were characterized for the first time in four samples from different origins. Turnip tops exhibit a high polyphenols content (ranging from 107 to 191 mg/100 g, fresh weight) and a good antiradical activity, determined with the DPPH* test. After a liquid-liquid extraction and fractionation procedures, most flavonoids (isorhamnetin, kaempferol, and quercetin glycosides) and hydroxycinnamic derivatives were identified by means of HPLC-DAD/MS techniques. Isorhamnetin glycosides were the main flavonoid derivatives, differing from that found in the vegetables belonging to the Brassica oleracea group.