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This study monitored changes in major carotenoids (lutein, ⍺-carotene, and β-carotene), free sugars (fructose, glucose, and sucrose), ascorbic acid, vitamin E, phytosterols (campesterol, stigmasterol, and β-sitosterol), fatty acid composition, total phenol content (TPC), total flavonoid content (TFC), total anthocyanin content, and antioxidant activities (AA); ferric-reducing antioxidant power (FRAP) and 2,2′-azino-bis (3-ethylbenzothiazoline-6sulfonic acid) [ABTS] assays, in the inner and outer root tissues of nine carrot genotypes with orange, white, and purple roots. The results showed a differential accumulation of bioactive compounds and antioxidant activities depending on root tissue and color. Carotenoids, free sugars, and total phytosterol contents were higher in genotypes with orange roots than in other genotypes. Ascorbic acid, TPC, TFC, total anthocyanin, and AA were highest in purple-colored carrots while vitamin E content was higher in white/purple carrots. Root color was highly related to the accumulation of individual carotenoids, vitamin E isomers, and total anthocyanin content most prominently among the analyzed bioactive compounds and AA. Free sugar and carotenoid contents were relatively higher in outer tissues than in inner tissues. Furthermore, ascorbic acid, TPC, TFC, and AA were statistically higher or similar in outer tissues when compared to inner tissues in all genotypes. In contrast, trends in vitamin E and phytosterol content were inconsistent between the inner and outer tissues, depending on the genotype. Although fatty acid composition was affected by both root color and tissue, the results were not significant. Thus, the phytochemical profile and content were highly dependent on root color and tissue in carrot genotypes. This may be useful in the food processing and pharmaceutical industries for the extraction of targeted bioactive compounds.

This study aimed to determine the optimal light conditions for the protected cultivation of Centella asiatica—a herbaceous medicinal plant with high bioactive content and antioxidant potential. The growth, triterpene glycoside content, total phenol content (TPC), total flavonoid content (TFC), and antioxidant activities of seedlings grown for five weeks under different light intensities (150 and 200 μmol m−2 s−1) and qualities (red and blue light ratios: 10:0, 8:2, and 6:4) were evaluated. Light intensity and quality significantly affected the studied parameters. At 150 μmol m−2 s−1 photosynthetic photon flux density (PPFD), most growth parameters decreased as the blue light ratio increased; however, the plants showed extreme epinasty under the sole red light treatment. Growth performance was highest under 20% blue light and 200 μmol m−2 s−1 PPFD. At both light intensities, the total triterpene glycoside content was higher for the sole red light and 20% blue light treatments than the 40% blue light treatment. Moreover, the TPC, TFC, and antioxidant activity increased as the blue light ratio increased. In conclusion, artificial light conditions affect the growth and secondary metabolite production of C. asiatica differentially, and 20% blue light at a higher light intensity (200 μmol m−2 s−1) is optimum for growing C. asiatica.

Carrot (Daucus carota), one of the most economically important root vegetables, shows a wide range of morphological and biochemical diversity. However, there is a lack of simultaneous systematic study regarding the biochemical composition and morphological characteristics in carrot genetic resources, which is crucial for crop improvement. For this reason, the morphological characteristics, carotenoids, and free sugar content of 180 carrot genetic resources grown in open field conditions from March to June 2020 were accessed to select the lines for a potential breeding program. Altogether, 15 qualitative and 4 quantitative agronomical characteristics were evaluated and grouped into four categories based on root color (orange, yellow, white, and purple). Three carotenoids (lutein, α-carotene, and β-carotene) and three free sugars (fructose, glucose, and sucrose) were also analyzed. The results revealed wide genetic variation in both qualitative and quantitative traits. Most of the genetic resources were orange (n = 142), followed by white (n = 16), yellow (n = 14), and purple (n = 8). Carotenoid profile and content were highly dependent on root color and showed wide genetic variability, while sugar content and profile were independent of the root color. Alpha- and β- carotene were the major carotenoids in orange carrots representing 43.3 and 41.0% of total carotenoids. In contrast, lutein was most dominant in other colored carrots (79.7–98.6% of total carotenoids). In most of the genetic resources, sucrose was the most dominant free sugar, followed by glucose and fructose. The results of this study showed that some genetic resources elevated carotenoid and sugar content. The morphological and biochemical diversity observed in this study might be useful for improving the agronomic traits and biochemical content of carrot lines for breeding programs.

This study monitored changes in chlorophyll fluorescence (CF), growth parameters, soil moisture content, phytochemical content (proline, ascorbic acid, chlorophyll, total phenol content (TPC), and total flavonoid content (TFC)), and antioxidant activities in 12-day-old lettuce (Lactuca sativa L.) seedlings grown under drought stress (no irrigation) and control (well irrigated) treatments in controlled conditions for eight days. Measurements occurred at two-day intervals. Among ten CF parameters studied, effective quantum yield of photochemical energy conversion in PSII (Y(PSII)), coefficient of photochemical quenching (qP), and coefficient of photochemical quenching of variable fluorescence based on the lake model of PSII (qL) significantly decreased in drought-stressed seedlings from day 6 of treatment compared to control. In contrast, maximum quantum yield (Fv/Fm), ratio of fluorescence (Rfd), and quantum yield of non-regulated energy dissipation in PSII (Y(NO)) were significantly affected only at the end. All growth parameters decreased in drought-stressed seedlings compared to control. Proline started increasing from day 4 and showed ~660-fold elevation on day 8 compared to control. Chlorophyll, ascorbic acid, TPC, TFC, and antioxidant activities decreased in drought-stressed seedlings. Results showed major changes in all parameters in seedlings under prolonged drought stress. These findings clarify effects of drought stress in lettuce seedlings during progressive drought exposure and will be useful in the seedling industry.

Chlorophyll fluorescence (CF), growth parameters, phytochemical contents [proline, chlorophyll, ascorbic acid, total phenol content (TPC), total flavonoid content (TFC)], and antioxidant activities were investigated in lettuce (Lactuca sativa L.) seedlings grown under different sodium chloride (NaCl) concentrations (0, 50, 100, 200, 300, and 400 mM) in a controlled environment for eight days. The parameters were evaluated at two days intervals. Almost of the CF and growth parameters as well as phytochemicals were significantly affected by both NaCl concentrations and progressive treatment schedule. The maximum quantum yield (Fv/Fm), effective quantum yield of photochemical energy conversion in PSII [Y(PSII)], coefficient of photochemical quenching (qP), coefficient of non-photochemical quenching (qN), and ratio of fluorescence decline (Rfd) showed decrements only at the highest saline concentration (400 mM), whereas the quantum yield of non-regulated energy dissipation in PSII [Y(NO)] exhibited a dissipation trend. All the growth parameters decreased with increasing NaCl concentrations, showing the highest decrease (~8 fold) in shoot fresh weight, compared to control seedlings. Proline significantly increased with increasing NaCl concentration and treatment time. Other phytochemicals decreased with the increase in NaCl concentration and reached their lowest at 400 mM. Overall, the results showed major changes in all parameters when the seedlings were grown at a NaCl concentration of 400 mM. The present findings will be useful for understanding the differential effect of NaCl concentrations in lettuce seedlings, and also might be useful to optimize the NaCl concentrations in other crops grown in controlled environmental conditions.

Individual glucosinolates (GSLs) were assessed to select cabbage genotypes for a potential breeding program. One hundred forty-six cabbage genotypes from different origins were grown in an open field from March to June 2019; the cabbage heads were used for GSL analyses. Seven aliphatics [glucoiberin (GIB), progoitrin (PRO), epi-progoitrin (EPI), sinigrin (SIN), glucoraphanin (GRA), glucoerucin (GER) and gluconapin (GNA)], one aromatic [gluconasturtiin (GNS)] and four indolyl GSLs [glucobrassicin (GBS), 4-hydroxyglucobrassicin (4HGBS), 4-methoxyglucobrassicin (4MGBS), neoglucobrassicin (NGBS)] were found this study. Significant variation was observed in the individual GSL content and in each class of GSLs among the cabbage genotypes. Aliphatic GSLs were predominant (58.5%) among the total GSLs, followed by indolyl GSL (40.7%) and aromatic GSLs (0.8%), showing 46.4, 51.2 and 137.8% coefficients of variation, respectively. GIB, GBS and NGBS were the most common GSLs found in all genotypes. GBS was the most dominant GSL, with an average value of 3.91 µmol g−1 (0.79 to 13.14 µmol g−1). SIN, GIB, PRO and GRA were the other major GSLs, showing average values of 3.45, 1.50, 0.77 and 0.62 µmol g−1, respectively. The genotypes with relatively high contents of GBS, SIN, GIB and GRA warrant detailed studies for future breeding programs since the hydrolysis products of these GSLs have several anti-cancer properties.

Glucosinolate (GSL) profiles and concentrations in various tissues (seeds, sprouts, mature root, and shoot) were determined and compared across nine Brassica species, including cauliflower, cabbage, broccoli, radish, baemuchae, pakchoi, Chinese cabbage, leaf mustard, and kale. The compositions and concentrations of individual GSLs varied among crops, tissues, and growth stages. Seeds had highest total GSL concentrations in most of crops, whereas shoots had the lowest GSL concentrations. Aliphatic GSL concentrations were the highest in seeds, followed by that in sprouts, shoots, and roots. Indole GSL concentration was the highest in the root or shoot tissues in most of the crops. In contrast, aromatic GSL concentrations were highest in roots. Of the nine crops examined, broccoli exhibited the highest total GSL concentration in seeds (110.76 µmol·g−1) and sprouts (162.19 µmol·g−1), whereas leaf mustard exhibited the highest total GSL concentration in shoots (61.76 µmol·g−1) and roots (73.61 µmol·g−1). The lowest GSL concentrations were observed in radish across all tissues examined.

This research was conducted to evaluate glucosinolate profiles, vitamin C, total phenol, total flavonoid, and free sugar (glucose, fructose, and sucrose) content, fatty acid composition, and antioxidant activity in floret and leaf of six cauliflower and broccoli cultivars. The level of chemical constituents as well as antioxidants significantly varied among crop types, cultivars, and their different parts, in that phytochemicals such as glucosinolate were statistically higher in florets compared with leaves in both broccoli and cauliflower cultivars. In contrast, total flavonoid and free sugar were found at higher levels in the leaf parts. The Asia purple cultivar exhibited statistically higher vitamin C (649.7 mg·100 g−1), total phenol (1345.2 mg·GAE 100 g−1), and total flavonoid (632.7 mg·CE 100 g−1) contents and consequently had the highest antioxidant activity (1.12 mg·mL−1) in its florets, while Baeridom and Bridal had the highest total glucosinolate (9.66 µmol·g−1) and free sugar (318.6 mg·g−1) contents, respectively compared with other cultivars. Likewise, the major fatty acids were palmitic (23.52%–38.42%), linoleic (13.09%–18.97%), and linolenic (26.32%–51.80%) acids, which comprised the highest compositional ratio (more than 50%) of polyunsaturated fatty acids (PUFAs) in most cultivars. Among the antioxidants, total phenol exhibited the most significant positive correlation (r = 0.698 **) with antioxidant activity, followed by vitamin C (r = 0.522 **) and total flavonoid (r = 0.494 **), indicating their significant contributions to total antioxidant activity.