Abundant Allelochemicals and the Inhibitory Mechanism of the Phenolic Acids in Water Dropwort for the Control of Microcystis aeruginosa Blooms

In recent years, with the frequent global occurrence of harmful algal blooms, the use of plant allelopathy to control algal blooms has attracted special and wide attention. This study validates the possibility of turning water dropwort into a biological resource to inhibit the growth of harmful Microcystis aeruginosa blooms via allelopathy. The results revealed that there were 33 types of allelopathic compounds in the water dropwort culture water, of which 15 were phenolic acids. Regarding water dropwort itself, 18 phenolic acids were discovered in all the organs of water dropwort via a targeted metabolomics analysis; they were found to be mainly synthesized in the leaves and then transported to the roots and then ultimately released into culture water where they inhibited M. aeruginosa growth. Next, three types of phenolic acids synthesized in water dropwort, i.e., benzoic, salicylic, and ferulic acids, were selected to clarify their inhibitory effects on the growth of M. aeruginosa and their mechanism(s) of action. It was found that the inhibitory effect of phenolic acids on the growth of M. aeruginosa increased with the increase of the exposure concentration, although the algae cells were more sensitive to benzoic acid than to salicylic and ferulic acids. Further study indicated that the inhibitory effects of the three phenolic acids on the growth of M. aeruginosa were largely due to the simultaneous action of reducing the number of cells, damaging the integrity of the cell membrane, inhibiting chlorophyll a (Chl-a) synthesis, decreasing the values of F0 and Fv/Fm, and increasing the activity of the antioxidant enzymes (SOD, POD, and CAT) of M. aeruginosa. Thus, the results of this study indicate that both culture water including the rich allelochemicals in water dropwort and biological algae inhibitors made from water dropwort could be used to control the growth of noxious algae in the future.

Enhancement of Anti-Proliferative Activity of the Extracts from Dehulled Adlay by Fermentation with Bacillus subtilis

Dehulled adlay was fermented with Bacillus subtilis BJ3-2, the anti-proliferative activities of the extracts from fermented dehulled adlay were investigated with six types of tumor cells, and then the bioactive components and the anti-proliferative mechanism were primarily explored. Results showed that all the extracts of B. subtilis-fermented dehulled adlay (BDA) and dehulled adlay (DA) had no inhibition effect on human embryonic kidney 239T cells. The anti-proliferative activities of the extracts from BDA against six types of tumor cells were almost always significantly higher than DA. Compared with others, the n-butanol extract of BDA (BDA-Nb) exhibited stronger anti-proliferative activities against human leukemia K562 cells and human non-small cell lung cancer A549 cells. Importantly, the anti-proliferative activity of fermented dehulled adlay against K562 cells was firstly discovered. Meanwhile, BDA-Nb was rich in tetramethylpyrazine, γ-aminobutyric acid, protocatechuic, 2,3,4-trihydroxybenzoic, chlorogenic, p-hydroxybenzoic, caffeic, trans-cinnamic, ferulic acids, and rutin. BDA-Nb induced the proliferative inhibition of K562 and A549 cells due to abnormal cell morphology, the increased cell population in G1 phase and apoptosis rate, the downregulation of Bcl-2, and the upregulation of Bax and caspase-3/8/9. These results indicate that dehulled adlay fermented with B. subtilis could be a potential therapeutic agent for leukemia and lung cancer.

Metabolite profiling and antioxidant capacity of lettuce Lactuca sativa var. longifolia grown in aquaponic system irrigated with shrimp effluents

This paper focuses on the quality of lettuce var. longifolia grown with shrimp effluents from well water (WW), diluted seawater (DSW) and a hydroponic solution (HS). Results evidenced that WW and DSW effluents slightly decreased weight, foliage, and yield (5-9%) in plants compared to HS control. Furthermore, WW-lettuce showed a higher level of total phenolic compounds (~71%), flavonoids (~90%), and antioxidant capacity (0.7-3-folds) than HS-plants, mainly in the soluble fraction. WW-lettuce also showed a higher content of total soluble solids (~16%) and, a lower saturation of color, which correlated significantly (p <0.05) with chlorophyll a. WW-lettuce exhibited the highest concentrations of p-hydroxybenzoic, p-coumaric and ferulic acids, as well as quercetin 3-O-glucoside and quercetin 3-O-ramnoside. Whereas DSW-lettuce showed the highest levels of caffeic acid, isorhamnetin 3-O-glucoside, kaempferol 3-O-glucoside, kaempferol and quercetin. HS-lettuce showed a higher proline content than the lettuces from the other treatments. These results indicate that aquaponic lettuce culture with shrimp effluent from WW could be used as an alternative culture system to reduce land area requirements, decrease or eliminate the discharge and impact of shrimp effluents, and simultaneously improve the functional properties of lettuce.

CHEMICAL COMPOSITION AND BIOLOGICAL ACTIVITY OF THE DRY EXTRACT "ROSMATIN" FROM THE HERB OF DRACOCEPHALUM MOLDAVICA L.

Moldavian Dragonhead (Dracocephalum moldavica L.) is an annual herb. In FGBNU VILAR a new variety of Moldavian Dragonhead «Nezhnost» has been developed. From the herb of the Moldavian Dragonhead, a technology has been developed for obtaining a dry purified extract, which has received the code name «Rozmatin». By NMR (1H and 13C) and HPLC-DAD-MS using standard samples and literature data, the qualitative and quantitative composition of the dry extract "Rozmatin" from the herb of the Dracocephalum moldavica was established. Rosmarinic, caffeic and ferulic acids, rosmarinic acid 3-O-glucoside, luteolin-7-O-β-D-glucuronide, acacetin-7-O-β-D-glucopyranoside (tilianin), apigenin-7-O-β-D-glucoside (Cosmosiin), apigenin-7-O-β-D-glucuronide, chrysoeryol-7-O-β-D-glucuronide, apigenin-7-O-β-D-(6ʺ-O-malonyl) glucoside, acacetin-7-O-β-D-glucuronide, acacetin-7-O-β-D-(6ʺ-malonyl) glucoside, schizotenuin F were identified. It was found that the content of rosmarinic acid in "Rosmatin" is 56.6%, the amount of flavonoids - about 27%. The study of anti-inflammatory and gastroprotective activity of "Rozmatin" in doses of 10 mg/kg, 100 mg/kg was carried out. A dose-dependent anti-inflammatory effect with suppression of the development of the exudative phase of inflammation, as well as a dose-dependent gastroprotective effect of "Rozmatin"", significantly exceeding the similar effect of the referent drug omeprazole, was revealed. Earlier it was found that "Rozmatin" has a tonic effect on the cardiovascular and nervous systems.

Precursor-Boosted Production of Metabolites in Nasturtium officinale Microshoots Grown in Plantform Bioreactors, and Antioxidant and Antimicrobial Activities of Biomass Extracts

The study demonstrated the effects of precursor feeding on the production of glucosinolates (GSLs), flavonoids, polyphenols, saccharides, and photosynthetic pigments in Nasturtium officinale microshoot cultures grown in Plantform bioreactors. It also evaluated the antioxidant and antimicrobial activities of extracts. L-phenylalanine (Phe) and L-tryptophan (Trp) as precursors were tested at 0.05, 0.1, 0.5, 1.0, and 3.0 mM. They were added at the beginning (day 0) or on day 10 of the culture. Microshoots were harvested after 20 days. Microshoots treated with 3.0 mM Phe (day 0) had the highest total GSL content (269.20 mg/100 g DW). The qualitative and quantitative profiles of the GSLs (UHPLC-DAD-MS/MS) were influenced by precursor feeding. Phe at 3.0 mM stimulated the best production of 4-methoxyglucobrassicin (149.99 mg/100 g DW) and gluconasturtiin (36.17 mg/100 g DW). Total flavonoids increased to a maximum of 1364.38 mg/100 g DW with 3.0 mM Phe (day 0), and polyphenols to a maximum of 1062.76 mg/100 g DW with 3.0 mM Trp (day 0). The precursors also increased the amounts of p-coumaric and ferulic acids, and rutoside, and generally increased the production of active photosynthetic pigments. Antioxidant potential increased the most with 0.1 mM Phe (day 0) (CUPRAC, FRAP), and with 0.5 mM Trp (day 10) (DPPH). The extracts of microshoots treated with 3.0 mM Phe (day 0) showed the most promising bacteriostatic activity against microaerobic Gram-positive acne strains (MIC 250–500 µg/mL, 20–21 mm inhibition zones). No extract was cytotoxic to normal human fibroblasts over the tested concentration range (up to 250 μg/mL).

Bioaccessibility and Gut Metabolism of Free and Melanoidin-Bound Phenolic Compounds From Coffee and Bread

The aim of this study is to investigate the bioaccessibility and gut metabolism of free and melanoidin-bound phenolic compounds from coffee and bread. Phenolics from coffee were predominantly found in free forms (68%, mainly chlorogenic acids), whereas those from bread were mostly bound to melanoidins (61%, mainly ferulic acid). Bioacessibility of coffee total free phenolics slightly decreased during simulated digestion (87, 86, and 82% after the oral, gastric, and intestinal steps, respectively), with caffeoylquinic acids being isomerized and chlorogenic acids being partially hydrolyzed to the corresponding hydroxycinnamic acids. Bioacessibility of bread total free phenolics decreased during simulated digestion (91, 85, and 67% after the oral, gastric, and intestinal steps, respectively), probably related to complexation with the proteins in simulated gastric and intestinal fluids. Upon gut fermentation, the bioaccessibility of total free phenolics from both coffee and bread decreased, mainly after the first 4 h (56 and 50%, respectively). Caffeic and ferulic acids were the predominant metabolites found during coffee and bread gut fermentation, respectively. Melanoidin-bound phenolics from coffee and bread were progressively released after the gastric and intestinal steps, probably due to hydrolysis caused by the acidic conditions of the stomach and the action of pancreatin from the intestinal fluid. The bioaccessibilities of all phenolics from coffee and bread melanoidins after the gastric and intestinal steps were, on average, 11 and 26%, respectively. During gut fermentation, phenolics bound to both coffee and bread melanoidins were further released by the gut microbiota, whereas those from coffee were also metabolized. This difference could be related to the action of proteases on melanoproteins during gastrointestinal digestion, probably anticipating phenolics release. Nevertheless, bioaccessibilities of melanoidin-bound phenolics reached maximum values after gut fermentation for 24 h (50% for coffee and 51% for bread). In conclusion, the bioaccessibilities of coffee and bread free phenolics during simulated digestion and gut fermentation were remarkably similar, and so were the bioaccessibilities of coffee and bread melanoidin-bound phenolics.

Selective Inhibition of Wild Sunflower Reproduction with Mugwort Aqueous Extract, Tested on Cytosolic Ca2+ and Germination of the Pollen Grains

Wild sunflower (Helianthus annuus L.) is an invasive species widely distributed in several regions of the world, where it shares a large area with domesticated sunflower. The imidazolinone-tolerant sunflower enables the control of problematic weeds (such as Xanthium spp., Brassica spp., wild sunflower) with imidazolinone herbicides (Clearfield® production system) in cultivated sunflower crops, but could facilitate the gene transfer of herbicide resistance, from cultivated sunflower to wild sunflower, generating hard-to-control weed biotypes or herbicide-resistant populations. The development of new practices that involve the selective inhibition of reproduction structures, such as pollen granules, could be an innovative strategy to minimize outcrossing and the origin of weed–crop hybrids in Clearfield® production systems. In this study, the effects of mugwort (Artemisia vulgaris L.) aqueous extract on cytosolic Ca2+ and the germination of pollen grains collected from conventional, wild and IMI-tolerant sunflower were tested. The results showed that mugwort deregulated Ca2+ homeostasis and markedly reduced the germination of conventional and wild sunflower pollen, but not IMI-tolerant pollen. The HPLC analysis revealed the presence of phenolic acids belonging to the hydroxycinnamic and benzoic classes in the mugwort extract. Hydroxycinnamic acids (caffeic and ferulic) deregulated the cytosolic Ca2+ of conventional and wild sunflower pollen, but not those which were IMI-tolerant, similar to mugwort extract. Selective inhibition of wild sunflower pollen in the Clearfield® sunflower crop contributes to a possible new weed management strategy, reducing the wild sunflower reproduction by seed, minimizing the potential risks of outcrossing with the formation of weed–crop hybrids. The Ca2+ selective chelating activity of caffeic or ferulic acids provides elements to be investigated for their possible use as an alternative to mugwort extract.

Phenolic Compounds from Leaves and Flowers of Hibiscus roseus: Potential Skin Cosmetic Applications of an Under-Investigated Species

The use of plant extracts in skin-care cosmetics is a modern trend due to their richness in polyphenols that act as anti-aging molecules. Hibiscus roseus is a perennial species naturalized in Italy, with beautiful soft pink flowers; its phenolic composition and biological activities have not been studied yet. The aim of this study was to characterize and quantify the phenolics and to evaluate the antioxidant, sun protection factor (SPF), and anti-collagenase activities of the ethanolic extracts of H. roseus leaves (HL) and flowers (HF). p-Coumaric, chlorogenic, and trans-ferulic acids derivatives as well as quercetin and kaempferol flavonoids were the main phenolic compounds detected. Catechin, epicatechin, kaempferol-3-O-rutinoside, kaempferol-3-O-glucoside, kaempferol-7-O-glucoside, tiliroside, oenin, and peonidin-3-O-glucoside were detected only in HF, while phloridzin was exclusive from HL, which also showed greater amounts of hydroxycinnamic acid derivatives. HF was richer in flavonoids and total phenolics, also exhibiting greater antioxidant capacity. The SPF and anti-collagenase activity of both extracts were similar and comparable to those of synthetic standards. The overall results demonstrate that H. roseus extracts are promising sources of bioactive phenolic compounds that could be potentially applied as anti-aging agents in skin-care cosmetics.