Broccoli inflorescences have been recognized as components of healthy diets on the basis of their high content of fiber, vitamin C, carotenoids, and glucosinolates/isothiocyanates. Broccoli sprouts have been recently shown to have high levels of glucoraphanin (4-methylsulfinylbutyl glucosinolate), the precursor of the chemoprotective isothiocyanate, sulforaphane. This study evaluated the effects of temperature and developmental stage on the glucosinolate content of broccoli sprouts. Seedlings cultivated using a 30/15 degrees C (day/night) temperature regime had significantly higher glucosinolate levels (measured at six consecutive days postemergence) than did sprouts cultivated at lower temperatures (22/15 and 18/12 degrees C; p < 0.001). Both higher (33.1 degrees C) and lower (11.3 degrees C) constant temperatures induced higher glucosinolate levels in sprouts grown to a uniform size. Glucosinolate levels were highest in cotyledons and lowest in roots of sprouts dissected both early and late in the 11 day developmental span investigated. Nongerminated seeds have the highest glucosinolate levels and concordantly greater induction of mammalian phase 2 detoxication enzymes. Levels decline as sprouts germinate and develop, with consistently higher glucosinolate content in younger developmental stages, independent of the temperature regime. Temperature stress or its associated developmental anomalies induce higher glucosinolate levels, specific elevations in glucoraphanin content, and parallel induction of phase 2 chemoprotective enzymes.

Research on natural and bioactive compounds is increasingly focused on their effects on human health, but there are unexpectedly few studies evaluating the relationship between climate and natural antioxidants. The aim of this study was analyze the biological role of six different Brassica vegetables (Brassica oleracea L. and Brassica rapa L.) as a natural source of antioxidant compounds. The antioxidant activity may be assigned to high levels of L-ascorbic acid, total phenolics and total flavonoids of each sample. The climate seasons affected directly the concentration of bioactive components and the antioxidant activity. Broccoli inflorescences and Portuguese kale showed high antioxidant activity in Spring-Summer whilst turnip leaves did so in Summer-Winter. The Brassica vegetables can provide considerable amounts of bioactive compounds and thus may constitute an important natural source of dietary antioxidants.

Broccoli (Brassica oleracea L. var. italica cv. Marathon) sprouts are a rich source of glucosinolates, particularly 4-methylsulfinylbutyl glucosinolate (glucoraphanin), the precursor of the chemoprotective isothiocyanate, sulforaphane. Sulfur and nitrogen fertilization have been shown to influence the pattern and levels of glucosinolates in mature broccoli, but little information is available on the fertilization of sprouts, a transient stage of broccoli growth, which have been recommended for salads. Therefore, an experiment was set up to evaluate the effect of N and S fertilization on the glucosinolate content of the aerial part and roots of broccoli sprouts. Nitrogen was tested at 0, 45.5, 91.0 mg L −1 and sulfur at 0, 14.6 and 29.2 mg L −1 . The results showed that total glucosinolates in the aerial part were significantly higher (P < 0.001) than in the roots. The major glucosinolates in the aerial part were 4-methylsulfinylbutyl and 3-methylsulfinylpropyl whereas in the roots they were 2-phenylethyl and 4-methylthiobutyl. Fertilization of broccoli sprouts had a significant (P < 0.001) detrimental effect on the levels of aliphatic glucosinolates whereas the opposite was noted for indole and aromatic glucosinolates, for some of the fertilization combinations tested. Overall, the results indicate that broccoli sprouts do not benefit from fertilization.

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The Brassicaceae rocket species Eruca sativa L. (salad rocket) and Diplotaxis tenuifolia L. (wild rocket) are consumed throughout the world in salads, predominantly the leaves but also the flowers and more recently the sprouts (seedlings). Ontogenic profiling of glucosinolates and flavonoids in plants derived from commercial seed of these species has previously been done, but no studies have been conducted to determine how geographical origin affects glucosinolate composition in rocket species. Seeds from wild E. sativa L. and D. tenuifolia L. from diverse regions of the world were obtained from gene banks and grown under controlled conditions. Sprouts were harvested when they would normally be harvested for consumption, and glucosinolates were extracted and profiled in these accessions. All of the sprouts from Italian E. sativa L. had consistently high total glucosinolate content, with only a few exceptions, and also the highest percentage contents of 4-mercaptobutylglucosinolate. In contrast, sprouts produced from Central and Eastern European seeds had a much higher percentage of 4-methylthiobutylglucosinolate. With a single exception, Tunisia, all sprouts produced from North African seeds had very high 4-methylthiobutylglucosinolate contents. The single sample from China had a high total glucosinolate content and glucosinolate profile that was very similar to the accessions from Uzbekistan and Pakistan. All of the D. tenuifolia L. sprouts had consistently high total glucosinolate contents, and a high percentage of this was 4-mercaptobutylglucosinolate. This glucosinolate variation in levels and profiles of the rockets can be used for genetic studies, selected breeding, and human intervention studies.

The aim of this study was to evaluate the phytochemical composition and the antioxidant properties of watercress (Nasturtium officinale R. Br., Brassicaceae) produced under organic production system. Fresh baby-leaf watercress samples were collected from local organic farms. High performance liquid chromatography with diode array detection (HPLC-DAD) and high performance liquid chromatography with diode array detection mass spectrometry (HPLC-MS) were used to assess the phytochemical composition, and spectrophotometric methods were used to assess the antioxidant capacity. Two major classes of healthier secondary plant metabolites were identified: phenolics and glucosinolates. The major phenolics determined were chlorogenic acid, quercetin-3-O-rutinoside, dicaffeoyltartaric acid, and isorhamnetin. The glucosinolates were composed exclusively of gluconasturtiin, the precursor of the anticarcinogenic, and antimicrobial compound 2-phenylethyl isothiocyanate. The extracts of organic young baby-leaf watercress presented high antioxidant capacity and this property was highly related with caffeic acid, quercetin-3-O-rutinoside, isorhamnetin, and glucosnastrutiin. The results achieved showed that baby-leaf watercress can provide high contents of antioxidant compounds at levels even superior to similar adult plant material.Keywords: watercress; baby-leaf samples; organic production; bioactive compounds; phenolic acids; flavonoids; quercetin-3-O-rutinoside; antioxidant activity El objetivo de este estudio fue evaluar la composición fitoquímica y propiedades antioxidantes de berros (Nasturtium officinale R. Br., Brassicaceae) producidos bajo el sistema de producción ecológico. Muestras frescas de hojas tiernas de berros se recolectaron en granjas ecológicas locales. HPLC-DAD y HPLC-MS fueron utilizados para evaluar la composición fitoquímica y métodos espectrofotométricos se utilizaron para evaluar la capacidad antioxidante. Se identificaron dos clases principales de metabolitos secundarios saludables de las plantas, compuestos fenólicos y glucosinolatos. Los principales compuestos fenólicos determinadas fueron: ácido clorogénico, quercetina-3-O-rutinósido, ácido dicafeoil tartárico y isoramnetina. Los glucosinolatos fueron compuestas exclusivamente por gluconasturtina, el precursor del compuesto anti-cancerígenos y antimicrobiana isotiocianato de 2-feniletilo. Los extractos de brotes jóvenes de berros ecológicos presentaron una alta capacidad antioxidante y esta propiedad fue muy relacionadas con el ácido cafeico, la quercetina-3-Orutinósido, isorhamnetina y glucosnastrutiina. Los resultados obtenidos mostraron que los brotes de berro puede proporcionar un alto contenido de compuestos antioxidantes a niveles aún superiores del material similar de la planta adulta. Palabras

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Summary The aim of this study was to evaluate the potential use of crop wastes (stems and leaves) from broccoli, beans and tomato to extract antioxidant polyphenols. Two different methods of extraction were performed: ultrasound (40 kHz) and conventional with 70 °C. In both methods, alkaline and acidic solvents were used. The polyphenol composition was assessed by HPLC‐DAD/UV‐VIS, and the 2,2‐diphenyl‐1‐picrylhydrazyl assay was used to measure the antioxidant activity. The results showed a significant variation of polyphenol composition and antioxidant activity with the type of sample, pH of solvent and extraction method. Also it was possible to observe that acidic methanol and 70 °C enables the extraction of significant amounts of phenolic acids and flavonoids. Based in our results, broccoli, green bean and tomato wastes can be used to extract antioxidant polyphenols, and the use of such wastes to extract polyphenols can be an opportunity to develop an environmental friendly management's systems creating incoming for producers and agro‐food sector.