Introduction. Ecologically Meaningful Germination Studies. Types of Seed Dormancy. Germination Ecology of Seeds with Nondeep Physiological Dormancy. Germination Ecology of Seeds with Morphophysiological Dormancy. Germination Ecology of Seeds with Physical Dormancy. Germination Ecology of Seeds in the Persistent Seed Bank. Causes of Within-Species Variations in Seed Dormancy and Germination Characteristics. A Geographical Perspective on Germination Ecology: Tropical and Subtropical Zones. A Geographical Perspective on Germination Ecology: Temperate and Arctic Zones. Germination Ecology of Plants with Specialized Life Cycles and/or Habitats. Biogeographical and Evolutionary Aspects of Seed Dormancy. Subject Index.

A Definitive Book on Seed Ecology@@@Seeds: Ecology, Biogeography, and Evolution of Dormancy and Germination

Summary
Phenolic compounds are secondary metabolites widely found in fruits, mostly represented by flavonoids and phenolic acids. The growing interest in these substances is mainly because of their antioxidant potential and the association between their consumption and the prevention of some diseases. The health benefits of these phytochemicals are directly linked to a regular intake and their bioavailability. Studies have shown the importance of the regular consumption of fruits, especially for preventing diseases associated with oxidative stress. In the present review, the most recent articles dealing with polyphenols in fruits are reviewed, focusing on their occurrence, main methods of extraction, quantification and antioxidant assays. In addition, the health benefits and bioaccessibility/bioavailability of phenolic compounds in fruits are addressed.

Phenolic compounds in fruits – an overview

Optimization of microwave-assisted extraction of polyphenols from Myrtus communis L. leaves.

Hypericum perforatum L.

Antimicrobial and antioxidative activity of extracts and essential oils of Myrtus communis L.

Objective To investigate the total phenolics, flavonoids and tannins content and the in vitro antioxidant activities of methanolic extracts of six wild Mentha species which are Mentha aquatica , Mentha arvensis , Mentha piperita , Mentha pulegium , Mentha rotundifolia and Mentha villosa . Methods The Folin–Ciocalteu method was used to determine the total phenols content while flavonoids were estimated according to the aluminum chloride colorimetric method. To evaluate tannins content, vanillin and HCl were added to methanolic extracts. The antioxidant potential was measured by 1,1-diphenyl-2-picrylhydrazyl radical scavenging, ferrous ion chelating and the inhibition of β-carotene bleaching assays. Results The methanol extracts of Algerian mints were rich in phenolic compounds and exhibited powerful antioxidant activity ranging from 7.5 μg/mL to 44.66 μg/mL, which varied significantly among species. Mentha aquatica stood out with efficient antioxidant ability which was correlated to the high total phenolics content, followed by Mentha arvensis and Mentha piperita with very close values, comparing to Mentha pulegium , Mentha rotundifolia and Mentha villosa with lowest values. Conclusions These results show that methanolic extracts of Mentha species from Algeria have a great potential of polyphenols which can be used as a natural food preservative and antioxidant source.

Total phenolic content and antioxidant activity of six wild Mentha species (Lamiaceae) from northeast of Algeria

Extracts of mature dark blue and white berries from two Tunisian Myrtus communis morphs growing at the same site were assessed for their essential-oil and fatty-acid compositions, phenolic contents, and antioxidant activities. The GC and GC/MS analyses of the essential oils allowed the identification of 33 constituents. The oils from the dark blue fruits showed high percentages of α-pinene (11.1%), linalool (11.6%), α-terpineol (15.7%), methyl eugenol (6.2%), and geraniol (3.7%). Myrtenyl acetate (20.3%) was found to be the major compound in the oils from white berries. GC Analysis of the pericarp and seed fatty acids showed that the polyunsaturated fatty acids constituted the major fraction (54.3-78.1%). The highest percentages of linoleic acid (78.0%) and oleic acid (20.0%) were observed in the seeds and the pericarps of the white fruits, respectively. The total phenol, flavonoid, and flavonol contents and the concentration of the eight anthocyanins, identified by HPLC analysis, were significantly higher in the dark blue fruits. All extracts showed a substantial antioxidant activity, assessed by the free radical-scavenging activity and the ferric reducing power, with the dark blue fruit extracts being more effective.

Myrtus communis berry color morphs: a comparative analysis of essential oils, fatty acids, phenolic compounds, and antioxidant activities.

The essential oil of 12 Tunisian natural populations of Myrtus communis L. (Myrtacea), prospected in three bioclimatic stages (humid inferior, sub-humid and semi-arid superior) were analyzed. Oil was extracted by n-hexane from crushed leaves and analysed by GC and GC-MS.



Twenty-four components, representing approximately 79.10% of the oil, were identified. The major constituents were α-pinene (19.20%) and 1,8-cineole (15.96%). The other important constituents were linalool (7.66%), α-terpineol (7.51%) and limonene (5.75%). The percentage of all components varied within and among populations according to their bioclimatic appurtenance. α-Pinene, camphene and 1,8-cineole were the main compounds to differentiate the populations according to the bioclimate. Copyright © 2005 John Wiley & Sons, Ltd.

Myrtus communis in Tunisia: variability of the essential oil composition in natural populations

In traditional medicine, myrtle (Myrtus communis L.) is frequently consumed as an infusion and decoction. In this study, we investigate the phenolic and volatile compositions and antioxidant and antibacterial activities of leaf infusions prepared during 3 different times. The total phenolics contents (146.74 to 179.55 mg GAE/g DM) varied significantly between infusions. Eleven phenolic compounds were identified by reversed-phase high-performance liquid chromatography. Phenolic acids (7.64 to 14.28 μmol/g DM) and flavonol glycosides (7.05 to 12.11 μmol/g DM) were the major phenolic fractions of infusions. Significant quantitative variation in 6 phenolic components was observed between infusions. Sixteen volatile components were identified by gas chromatography (GC) and GC mass spectrometry analyses. The main constituents were 1,8-cineole (42.58% to 51.39%), α-terpineol (9.45% to 9.72%), methyl eugenol (6.69% to 7.11%), and linalool (5.91% to 6.06%). Quantitative variations of the volatile components of the analyzed oils in relation to the infusion time were observed. The antioxidant properties of infusions, assayed through DPPH (2,2- diphenyl-1-picrylhydrazyl) method, β-carotene bleaching test, chelating effect on ferrous ions, and ferric reducing power method, were considerable and varied according to the infusion time. Myrtle infusions exhibited a substantial antimicrobial activity against 6 tested bacteria.

Chokri Messaoud

Papers

Total phenolic content and antioxidant activity of six wild Mentha species (Lamiaceae) from northeast of Algeria

Myrtus communis berry color morphs: a comparative analysis of essential oils, fatty acids, phenolic compounds, and antioxidant activities.

Myrtus communis in Tunisia: variability of the essential oil composition in natural populations

Myrtus communis L. infusions: the effect of infusion time on phytochemical composition, antioxidant, and antimicrobial activities.

Chemical composition and antioxidant activities of essential oils and methanol extracts of three wild Lavandula L. species