Within-plant variation in rosmarinus officinalis l. Terpenes and phenols and their antimicrobial activity against the rosemary phytopathogens alternaria alternata and pseudomonas viridiflava

This study investigated within-plant variability of the main bioactive compounds in rosemary (Rosmarinus officinalis L.). Volatile terpenes, including the enantiomeric distribution of monoterpenes, and phenols were analyzed in young and mature foliar, cortical and xylem tissues. In addition, antimicrobial activity of rosmarinic acid and selected terpenes was evaluated against two rosemary pathogens, Alternaria alternata and Pseudomonas viridiflava. Data showed that total concentration and relative contents of terpenes changed in relation to tissue source and age. Their highest total concentration was observed in the young leaves, followed by mature leaves, cortical and xylem tissues. Rosmarinic acid and carnosic acid contents did not show significant differences between leaf tissues of different ages, while young and mature samples showed variations in the content of four flavonoids. These results are useful for a more targeted harvesting of rosemary plants, in order to produce high-quality essential oils and phenolic extracts. Microbial tests showed that several terpenes and rosmarinic acid significantly inhibited the growth of typical rosemary pathogens. Overall, results on antimicrobial activity suggest the potential application of these natural compounds as biochemical markers in breeding programs aimed to select new chemotypes less susceptible to pathogen attacks, and as eco-friendly chemical alternatives to synthetic pesticides

Phenolic extracts from extra virgin olive oils inhibit dipeptidyl peptidase iv activity: In vitro, cellular, and in silico molecular modeling investigations

Two extra virgin olive oil (EVOO) phenolic extracts (BUO and OMN) modulate DPP-IV activity. The in vitro DPP-IV activity assay was performed at the concentrations of 1, 10, 100, 500, and 1000 μg/mL, showing a dose-dependent inhibition by 6.8 ± 1.9, 17.4 ± 6.1, 37.9 ± 2.4, 57.8 ± 2.9, and 81 ± 1.4% for BUO and by 5.4 ± 1.7, 8.9 ± 0.4, 28.4 ± 7.2, 52 ± 1.3, and 77.5 ± 3.5% for OMN. Moreover, both BUO and OMN reduced the DPP-IV activity expressed by Caco-2 cells by 2.9 ± 0.7, 44.4 ± 0.7, 61.2 ± 1.8, and 85 ± 4.2% and by 3 ± 1.9, 35 ± 9.4, 60 ± 7.2, and 82 ± 2.8%, respectively, at the same doses. The concentration of the most abundant and representative secoiridoids within both extracts was analyzed by nuclear magnetic resonance ((1)H-NMR). Oleuropein, oleacein, oleocanthal, hydroxytyrosol, and tyrosol, tested alone, reduced the DPP-IV activity, with IC(50) of 472.3 ± 21.7, 187 ± 11.4, 354.5 ± 12.7, 741.6 ± 35.7, and 1112 ± 55.6 µM, respectively. Finally, in silico molecular docking simulations permitted the study of the binding mode of these compounds

Comparison between in vitro chemical and ex vivo biological assays to evaluate antioxidant capacity of botanical extracts

The anti-oxidative activity of plant-derived extracts is well-known and confers health-promoting effects on functional foods and food supplements. Aim of this work is to evaluate the capability of two different assays to predict the real biological antioxidant efficiency. At this purpose, extracts from five different plant-derived matrices and commercial purified phytochemicals were analyzed for their anti-oxidative properties by using well-standardized in vitro chemical method (TEAC) and an ex vivo biological assay. The biological assay, a cellular membrane system obtained from erythrocytes of healthy volunteers, is based on the capability of phytochemicals treatment to prevent membrane lipid peroxidation under oxidative stress by UV-B radiation. Plant extracts naturally rich in phenols with different structure and purified phytochemicals showed different in vitro and ex vivo antioxidant capacities. A high correlation between phenolic contents of the plant-derived extracts and their ability to prevent oxidative injuries in a biological system was found, thus underlying the relevance of this class of metabolites in preventing oxidative stress. On the other hand, a low correlation between the antioxidant capacities was shown between in vitro and ex vivo antioxidant assay. Moreover, data presented in this work show how food complex matrices are more effective in preventing oxidative damages at biological level than pure phytochemicals, even if for these latter, the antioxidant activity was generally higher than that observed for food complex matrices

Characterization of arils juice and peel decoction of fifteen varieties of punica granatum l.: a focus on anthocyanins, ellagitannins and polysaccharides

Pomegranate is receiving renewed commercial and scientific interest, therefore a deeper knowledge of the chemical composition of the fruits of less studied varieties is required. In this work, juices from arils and decoctions from mesocarp plus exocarp were prepared from fifteen varieties. Samples were submitted to High Performance Liquid Chromatography—Diode Array Detector–Mass Spectrometry, spectrophotometric and colorimetric CIEL* a* b* analyses. Antioxidant, antiradical and metal chelating properties, inhibitory activity against tyrosinase and α-amylase enzymes were also evaluated. All varieties presented the same main phenols; anthocyanins and ellagitannins were widely variable among varieties, with the richest anthocyanin content in the juices from the Wonderful and Soft Seed Maule varieties (approx. 660 mg/L) and the highest ellagitannin content in the peel of the Black variety (approx. 133 mg/g dry matter). A good correlation was shown between the colour hue and the delphinidin/cyanidin ratio in juices (R 2= 0.885). Total polysaccharide yield ranged from 3% to 12% of the peels’ dry weight, with the highest content in the Black variety. Decoctions (24.44–118.50 mg KAE/g) showed better in vitro antioxidant properties and higher inhibitory capacity against tyrosinase than juices (not active-16.56 mg KAE/g); the inhibitory capacity against α-amylase was similar and quite potent for juices and decoctions. Knowledge about the chemical composition of different pomegranate varieties will allow for a more aware use of the different parts of the fruit

Study on a fermented whole wheat: Phenolic content, activity on PTP1B enzyme and in vitro prebiotic properties

Fermented cereals, staple foods in Asia and Africa, are recently receiving a growing interest in Western countries. The object of this work is the characterization of a fermented wheat used as a food ingredient and dietary supplement. To this aim, the phenolic composition, the activity on protein tyrosine phosphatase 1B (PTP1B), an enzyme overexpressed in type-II diabetes, the in vitro prebiotic properties on Lactobacillus reuteri and the microbial composition were investigated. Basic and acidic hydrolysis were tested for an exhaustive recovery of bound phenols: the acidic hydrolysis gave best yields. Methyl ferulate and neocarlinoside were identified for the first time in wheat. The inhibitory power of the extracts of several batches were investigated on PTP1B enzyme. The product was not able to inhibit the enzyme, otherwise, for the first time, a complete inhibition was observed for schaftoside, a major C-flavonoid of wheat. The microbial composition was assessed identifying Lactobacillus, Enterococcus, and Pediococcus as the main bacterial species. The fermented wheat was a suitable substrate for the grown of L. reuteri, recognized for its health properties in the human gut. The proposed method for phenols is easier compared to those based on strong basic hydrolysis; our results assessed the bound phenols as the major fraction, differently from that suggested by the literature for fermented cereals

Daily consumption of a high-phenol extra-virgin olive oil reduces oxidative DNA damage in postmenopausal women

Extra-virgin olive oils (EVOO), high in phenolic compounds with antioxidant properties, could be partly responsible for the lower mortality and incidence of cancer and CVD in the Mediterranean region. The present study aims to measure oxidative DNA damage in healthy human subjects consuming olive oils with different concentrations of natural phenols. A randomised cross-over trial of high-phenol EVOO (high-EVOO; 592 mg total phenols/kg) v. low-phenol EVOO (low-EVOO; 147 mg/kg) was conducted in ten postmenopausal women in Florence. Subjects were asked to substitute all types of fat and oils habitually consumed with the study oil (50 g/d) for 8 weeks in each period. Oxidative DNA damage was measured by the comet assay in peripheral blood lymphocytes, collected at each visit during the study period. Urine samples over 24 h were collected to measure the excretion of the olive oil phenols. The average of the four measurements of oxidative DNA damage during treatment with high-EVOO was 30 % lower than the average during the low-EVOO treatment (P=0.02). Urinary excretion of hydroxytyrosol and its metabolite homovanillyl alcohol were significantly increased in subjects consuming high-EVOO. Despite the small sample size, the present study showed a reduction of DNA damage by consumption of an EVOO rich in phenols, particularly hydroxytyrosol