Hydrolysable tannins (HTs), secondary metabolites widely distributed in the plant kingdom, are generally multiple esters of gallic acid with glucose. HTs have been shown to be effective antagonists against viruses, bacteria and eukaryotic microorganisms. The present review examines the antimicrobial and antiviral activity of HTs, the mechanism(s) of action, and some structure-activity relationships.
During olive oil production, large volumes of water are generated and subsequently discarded. Olives contain a variety of bioactive components, and some of them, according to their partition coefficients, end up in the water phase. The current investigation aimed at comparing different methods for the extraction of biologically active components of the olive mill waste waters (OMWW) and evaluating the in vitro antioxidant and anti-inflammatory activities of the resulting extracts. The results indicate that OMWW extracts are able to inhibit human LDL oxidation (a process involved in the pathogenesis of atherosclerosis) and to scavenge superoxide anions and hypochlorous acid at concentrations as low as 20 ppm. Finally, two of the three extracts also inhibited the production of leukotrienes by human neutrophils. The potency of the extracts depended on their degree of refinement: extracts containing only low molecular weight phenols were the most effective.
Experiments were conducted on Phillyrea latifolia plants grown under a dense overstorey of Pinus pinea (shade plants) or on seashore dunes (sun plants) in a coastal area of Tuscany (42m 46h N, 10m 53h E). Total integrated photon flux densities averaged 1n67 and 61n4 m mol m −# d −" for shade and sun sites, respectively. A leaf morphological-structural analysis, a qualitative and quantitative analysis of phenylpropanoids of leaf tissue and leaf surface, and a histochemical localization of flavonoids were conducted. The area of sun leaves reached 57% of that of shade leaves, whereas leaf angle (β), sclerophylly index (ratio of leaf d. wt : leaf area), and trichome frequency (trichome number mm −# ) were markedly greater in leaves exposed to full solar radiation than in leaves acclimated to shade. The total thickness of sun leaves was 78% higher than that of shade leaves, mostly owing to a greater development of both palisade parenchyma and spongy mesophyll. The concentration, but not the composition, of leaf tissue phenylpropanoids varied significantly between sun and shade leaves, with a marked increase in flavonoid glycosides in sun leaves. Flavonoids occurred almost exclusively in the upper epidermal cells of shade leaves. By contrast, flavonoids largely accumulated in the upper and lower epidermis, as well as in the mesophyll tissue of leaves that were acclimated to full sunlight. Flavonoid glycosides were found exclusively in the secretory products of glandular trichomes of P. latifolia leaves exposed to high levels of light ; luteolin 7-Oglucoside and quercetin 3-O-rutinoside were the major constituents. By contrast, verbascoside and an unidentified caffeic acid derivative constituted 72% of total phenylpropanoids secreted by glandular trichomes of shade leaves, whereas they were not detected in glandular trichomes of sun leaves. These findings suggest that the light-induced synthesis of flavonoids in glandular trichomes of P. latifolia probably occurs in situ and concomitantly inactivates other branch pathways of the general phenylpropanoid metabolism. This is the first report of the key role of glandular trichomes and of flavonoid glycosides in the integrated mechanisms of acclimation of P. latifolia to excess light.
Olea europaea L. fruit is a peculiar vegetal matrix containing high levels of fatty acids (98–99% of the total weight of extra-virgin olive oil, EVOO) and low quantities (1–2%) of phenolics, phytosterols, tocopherols, and squalene. Among these minor components, phenolics are relevant molecules for human health. This review is focused on their beneficial activity, in particular of hydroxytyrosol (HT), oleuropein (OLE), oleocanthal (OLC), and lignans found in EVOO, olive oil by-products and leaves. Specifically, the cardioprotective properties of the Mediterranean diet (MD) related to olive oil consumption, and the biological activities of polyphenols recovered from olive oil by-products and leaves were described. Recent European projects such as EPIC (European Prospective Investigation into Cancer and Nutrition) and EPICOR (long-term follow-up of antithrombotic management patterns in acute coronary syndrome patients) have demonstrated the functional and preventive activities of EVOO showing the relation both between cancer and nutrition and between consumption of EVOO, vegetables, and fruit and the incidence of coronary heart disease. The data reported in this review demonstrate that EVOO, one of the pillars of the MD, is the main product of Olea europaea L. fruits; leaves and by-products are secondary but precious products from which bioactive compounds can be recovered by green technologies and reused for food, agronomic, nutraceutical, and biomedical applications according to the circular economy strategy.
11The antiradical activity, polyphenols, flavonoids and total condensed tannins contents have been determined in the case of seven local 12 edible Brassicaceae, i.e. Italian kale, broccoli, Savoy and white cabbage, cauliflower, green cauliflower and Brussels sprouts. Rapid spec-13 trophotometric methods were applied. The results achieved were compared with the quali-quantitative information obtained by HPLC/ 14 DAD and HPLC/MS. The polyphenolic compounds detected were: kaempferol and quercetin glycosides and hydroxycinnamic esters. 15 The EC 50 values ranged from 81.45 to 917.81 mg sample/mg DPPH Å and the total phenolic content from 4.30 to 13.80 gallic acid equiv-16 alents (mg gallic acid/g sample). The peculiar characteristics of these vegetables can be evaluated and can increase their value as func-17 tional food. 18
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.
The antiradical activity of dry beans was evaluated in order to assess the validity of this test and to correlate the results with those achieved with the Folin-Ciocalteu method and with a rapid spectrophotometric method for the analysis of total flavonoids. Four landraces (12 samples) of common beans (Phaseolus vulgaris L.), collected in two regions of Italy (Tuscany and Basilicata) in three different years, were analyzed. The EC50 values ranged from 39 to 2810 mg sample/mg 1,1-diphenyl-2-picrylhydrazil radical. The phenolic content of each sample was expressed as gallic acid equivalents; it changed from 1.17 to 4.40 mg/g. The flavonoid content, expressed as mg of (+)-catechin per g of dry seeds, ranged from 0.24 to 1.43 mg/g. The qualiquantitative composition of polyphenols has been also elucidated by means of high-performance liquid chromatography (HPLC)-diode array detection and HPLC/MS. These investigations showed that rapid tests can contribute to assessing the quality of functional food.
The soy isoflavone genistein targets adipose tissue and elicits physiological effects that may vary based on dietary intake. We hypothesized that the adipose effects of genistein are dose and gender dependent. Four-week-old C57BL/6 male and female mice received daily oral doses of genistein (50-200,000 microg/kg.d) or 17beta-estradiol (E2) (5 microg/kg.d) for 15 d or a diet containing 800 ppm genistein. Genistein increased epididymal and renal fat pad and adipocyte size at doses up to 50,000 microg/kg.d or at 800 ppm in the diet in males but not in females. The alteration in adipocity correlated with changes in peripheral insulin resistance. These treatments increased genistein serum concentrations from 35+/-6 to 103+/-26 nM 12 h after treatment and lowered plasma triglycerides and cholesterol levels. The 200,000 microg/kg.d genistein dose decreased adipose tissue weight similarly to E2. This genistein dose down-regulated estrogen receptor (beta more than alpha) and progesterone receptor expression and induced estrogen-dependent adipose differentiation factors; it did not change expression of the minimal consensus estrogen-responsive element in ERE-tK-LUC mice, which was positively modulated in other tissues (e.g. the lung). E2 down-regulated almost all examined adipogenic factors. Gene microarray analysis identified factors in fat metabolism and obesity-related phenotypes differentially regulated by low and high doses of genistein, uncovering its adipogenic and antiadipogenic actions. The lower dose induced the phospholipase A2 group 7 and the phospholipid transfer protein genes; the 200,000 microg/kg.d dose inhibited them. The antiadipogenic action of genistein and down-regulation of adipogenic genes required the expression of ERbeta. In conclusion, nutritional doses of genistein are adipogenic in a gender-specific manner, whereas pharmacological doses inhibited adipose deposition.
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