Resilience of hop (Humulus lupulus L.) to salinity, heat and drought stresses: A mini-review.

Over recent years, the cultivation of hops (Humulus lupulus L.) has spread widely in the Mediterranean, also affecting the southern regions of Spain and Italy with a typical semi-arid climate. Several and recent studies have investigated the responses of this species to the main abiotic stresses, which is an aspect of absolute relevance to the knowledge of the adaptive capacity of hops to the growing conditions of a new cultivation environment. Moreover, given the fact that hops' phytochemical composition is determined primarily by genetic and environmental factors, and that the species is perennial, the lack of knowledge on the effects of abiotic stress could be reflected in subsequent years, which means multi-year economic risks. This review work therefore aims to showcase, based on an in-depth investigation of the available literature, the response of hop to the main abiotic stresses, and the effect of these on productive and qualitative crop performances. The data presented will be useful to the understanding of constraints and to the identification of useful coping strategies to the cultivation of hops in semi-arid Mediterranean environments.

Phenolic Profiles, Antioxidant and Anti-Inflammatory Activities of Hydrodistillation Wastewaters from Five Lamiaceae Species.

Distillation is the most widely used method to obtain an essential oil from plant material. The biomass used in the process is returned as a solid residue together with variable amounts of water rich in water-soluble compounds, which currently are not addressed to any further application. The scope of this work was to evaluate the phytochemical composition of wastewaters coming from hydrodistillation (DWWs) of five aromatic plants belonging to the Lamiaceae family, and to assess their in vitro antioxidant and anti-inflammatory activities. The phenolic profiles of the DWWs were determined by HPLC-DAD and HPLC-ESI/MS. Free radical scavenging ability, oxygen radical antioxidant capacity and superoxide dismutase mimetic activity of the samples under study were measured. Moreover, to investigate the anti-inflammatory activity of the DWWs, an in vitro experimental model of intestinal inflammation was used. The DWW samples' phytochemical analysis allowed the identification of 37 phenolic compounds, all exhibiting good antioxidant and anti-inflammatory activity. Our study contributes to the knowledge on the polyphenolic composition of the DWWs of five aromatic plants of the Lamiaceae family. The results highlight the presence of compounds with proven biological activity, and therefore of great interest in the pharmaceutical and nutraceutical fields.

Cultivation trials of hop (Humulus lupulus L.) in semi-arid environments.

The recent developments in the market and craft beer industry in Italy have led to an increasing demand for local raw materials, such as barley malt and hops. Few works have been addressed to evaluate suitability and productivity of hop in semi-arid Italian environments. With this purpose, two experiments were carried out in 2018 and 2019, testing the suitability to cultivation of three commonly used hop varieties (Cascade, Chinook and Nuggett) in two typical semi-arid environments in Sicily. Phenological stages were also evaluated, and GDDs accumulated in vegetative and reproductive stages were calculated according to 9 different methods, dealing with three Tbase temperatures (0 °C, 5 °C and 10 °C) and with different adjustments of daily thermal sums for Tmax values >30 °C. The obtained hop cones were used to prepare small batches of beer (fresh hop American Pale Ale), further submitted to sensory analysis through a panel test. The results have shown a high variability of yields and biometrical characteristics of the tested hop varieties according to the cropping management. However, a definite advantage showed up for the earliest maturing variety (Chinook), that allowed cones yield of 41 g per plant (d.m.) and biomass yield of 143 g per plant (d.m.). The sensory analyses assessed the excellent organoleptic characteristics of the obtained hop, as well as of the beer produced. Hop demonstrates to be a promising crop for semi-arid Mediterranean environments, although many aspects of cropping technique are still to be pointed out.

Variations of Essential Oil Constituents in Oregano (Origanum vulgare subsp. viridulum (= O. heracleoticum) over Cultivation Cycles.

Oregano is-probably-the most appreciated and widespread aromatic plant in Sicily. With the aim of evaluating the modifications of oregano's essential oil composition over time, between 2013 and 2015 six weekly samplings of three different oregano plantations were carried out, from the beginning of flowering (early May) until the traditional harvest moment (end of June). Samples were hydrodistilled and the obtained essential oils (EOs) were evaluated by means of a combination of GC-FID and GC-MS. The Origanum plants under study were demonstrated to belong to the high-yielding, thymol-type biotypes, with thymol, γ-terpinene and p-cymene as three main components, among the total of about 50 of the evaluated EOs. In each location, EO yields were found to increase throughout survey dates. Significant variations were found in many EO components, both across years and throughout harvest dates within locations. The choice of the harvest moment was confirmed to be crucial in assessing quality aspects of oregano.

Herbicidal Activity of Thymbra capitata (L.) Cav. Essential Oil.

The bioherbicidal potential of Thymbra capitata (L.) Cav. essential oil (EO) and its main compound carvacrol was investigated. In in vitro assays, the EO blocked the germination and seedling growth of Erigeron canadensis L., Sonchus oleraceus (L.) L., and Chenopodium album L. at 0.125 µL/mL, of Setaria verticillata (L.) P.Beauv., Avena fatua L., and Solanum nigrum L. at 0.5 µL/mL, of Amaranthus retroflexus L. at 1 µL/mL and of Portulaca oleracea L., and Echinochloa crus-galli (L.) P.Beauv. at 2 µL/mL. Under greenhouse conditions, T. capitata EO was tested towards the emergent weeds from a soil seedbank in pre and post emergence, showing strong herbicidal potential in both assays at 4 µL/mL. In addition, T. capitata EO, applied by spraying, was tested against P. oleracea, A. fatua and E. crus-galli. The species showed different sensibility to the EO, being E. crus-galli the most resistant. Experiments were performed against A. fatua testing T. capitata EO and carvacrol applied by spraying or by irrigation. It was verified that the EO was more active at the same doses in monocotyledons applied by irrigation and in dicotyledons applied by spraying. Carvacrol effects on Arabidopsis root morphology were also studied.

Control of Erigeron bonariensis with Thymbra capitata, Mentha piperita, Eucalyptus camaldulensis, and Santolina chamaecyparissus Essential Oils.

In the search of sustainable and environmentally friendly methods for weed control, there is increasing interest in essential oils (EOs) as an approach to reduce synthetic herbicide use. The phytotoxicity of Thymbra capitata, Mentha piperita, Eucalyptus camaldulensis, and Santolina chamaecyparissus EOs against the noxious weed Erigeron bonariensis were evaluated in pre- and post-emergence assays in greenhouse conditions. The EOs were applied at 2, 4, and 8 µL/mL, with Fitoil used as emulsifier. In post-emergence, two ways of application were tested, irrigation and spraying. Several germination parameters (germination %, mean germination time, and synchrony of the germination process) were evaluated in pre-emergence tests, and the phytotoxicity level was assessed in post-emergence. In pre-emergence, all EOs significantly reduced seed germination as compared to the controls, ranking: T. capitata > E. camaldulensis > S. chamaecyparissus > M. piperita. The effectiveness of all EOs varied with the tested dose, always following the rank 2 µL < 4 µL < 8 µL, with T. capitata EO showing full effectiveness even at the lowest dose. In post-emergence, T. capitata was the most effective EO, inducing a rather complete inhibition of plantlet growth at the highest two doses. These EOs demonstrated to have good potential for the formulation of natural herbicides.

Characterization of Sicilian rosemary (Rosmarinus officinalis L.) germplasm through a multidisciplinary approach.

In Sicily, small differences exist between wild and cultivated rosemary biotypes; VOCs and genetic profiles may be a useful tool to distinguish them. A germplasm collection of Rosmarinus officinalis L. was harvested from 15 locations in Sicily. Eleven wild and four cultivated populations were collected and, due to the surveyed area covered, they can be considered as a representative panel of Sicilian genetic background of the species. Ex situ plant collection was transferred to the field cultivation in homogeneous conditions for characterizing through a multidisciplinary approach. The study included morphological traits observations (growth habitus, flower color, number and size of leaves, length and number of internodes), VOC profiles using HS-SPME, genome size by flow cytometry analysis, and genetic characterization by means of DNA and nuclear microsatellite (nSSR) investigation. To detect any pattern within- and among-populations variability, all morphological and chemical data were submitted to ANOVA, while clustering and structure population analysis were carried out using genetic profiles. The present work allowed us to distinguish rather well between wild and cultivated genotypes and to underline the biodiversity richness among rosemary Sicilian germplasm, never highlighted, useful for future breeding programs addressed to exploit this important resource.

Variability of Hypericins and Hyperforin in Hypericum Species from the Sicilian Flora.

Within Sicilian flora, the genus Hypericum (Guttiferae) includes 10 native species, the most popular of which is H. perforatum. Hypericum's most investigated active compounds belong to naphtodianthrones (hypericin, pseudohypericin) and phloroglucinols (hyperforin, adhyperforin), and the commercial value of the drug is graded according to its total hypericin content. Ethnobotanical sources attribute the therapeutic properties recognized for H. perforatum, also to other Hypericum species. However, their smaller distribution inside the territory suggests that an industrial use of such species, when collected from the wild, would result in an unacceptable depletion of their natural stands. This study investigated about the potential pharmacological properties of 48 accessions from six native species of Hypericum, including H. perforatum and five 'minor' species, also comparing, when possible, wild and cultivated sources. The variability in the content of active metabolites was remarkably high, and the differences within the species were often comparable to the differences among species. No difference was enlightened between wild and cultivated plants. A carefully planned cultivation of Hypericum seems the best option to achieve high and steady biomass yields, but there is a need for phytochemical studies, aimed to identify for multiplication the genotypes with the highest content of the active metabolites.

Real cover crops contribution to soil organic carbon sequestration in sloping vineyard.

The research focused on the evaluation of the effect of soil erosion processes on SOC sequestration rate after 5 years of cover crop soil management in Mediterranean vineyards (Sicily, Italy). Two paired sites, one in a sloping area and another one in a contiguous flat area, were chosen. The vineyard soils of the two plots of each paired site were managed with conventional soil tillage (CT) and Vicia faba cover crop (CC) the preceding 5 years. SOC was measured in three points along the slope (top, middle and foot parts) and in the flat area. Results showed that in the slope area the highest SOC content was found in CC management, with an average value of 9.52 ±â€¯0.34 g kg-1, whereas the SOC content under CT was 8.74 ±â€¯0.20 g kg-1. In the flat vineyard, the SOC ranged from 9.88 ±â€¯0.11 g kg-1 to 10.47 ±â€¯0.20 g kg-1 under CT and CC, respectively. The SOC increase was 6% in the flat area and 9% in the sloping vineyard after five years since CC management adoption. The higher C sequestration rates in the sloping vineyard in comparison to the flat area could be attributed to the role of CC to prevent sediment and nutrient erosion. These results were compared with those by reference works and with the results of 39 vineyards paired-sites. Findings demonstrated that C sequestration rate is strongly correlated to slope gradient and the C sequestration per se due to the effect of added C input by the cover crop is overestimated.

Phytochemical profiles, phototoxic and antioxidant properties of eleven Hypericum species - A comparative study.

Hypericum is one out of the nine genera belonging to the botanical family Clusiaceae Lindl (syn. Hypericaceae Juss.; APG III, 2009). The genus contains 484 species spread worldwide, one of which, Hypericum perforatum, is largely used in folk medicine. The aim of this study was to evaluate the chemical composition, along with the antioxidant and phototoxic activity, of 11 Hypericum species grown in Sicily (H. perforatum L., H. aegypticum L., H. androsaemum L., H. calycinum L., H. hircinum L., H. hirsutum L., H. montanum L., H. patulum Thunb., H. perfoliatum L., H. pubescens Boiss., H. tetrapterum Fr.). Samples of flowering tops collected from these Hypericum species were extracted and analysed by high performance liquid chromatography with diode-array detection and mass spectrometry (HPLC-DAD-MS) to determine their content of main polyphenols, acylphloroglucinols, and naphthodianthrones. The extracts were also subjected to a photocytotoxic assay using murine fibroblast (NIH/3T3), and their antioxidant activity evaluated by means of Folin-Ciocalteau, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, and oxygen radical antioxidant capacity assays. Phytochemical analysis allowed us to identify and quantify 20 metabolites, each of them possessing a well-known biological activity. Furthermore, all examined species showed a good cytotoxic and antioxidant/radical scavenging activity. These results indicate that in addition to the well-known H. perforatum, at least other three species (H. tetrapterum, H. pubescens, and H. montanum) represent potential sources of biologically active compounds, and at least other two species (H. perfoliatum and H. tetrapterum), due to their phototoxicity are candidates for application in photodynamic therapy.

Arbuscular mycorrhizal fungi altered the hypericin, pseudohypericin, and hyperforin content in flowers of Hypericum perforatum grown under contrasting P availability in a highly organic substrate.

St. John's Wort (Hypericum perforatum) is a perennial herb able to produce water-soluble active ingredients (a.i.), mostly in flowers, with a wide range of medicinal and biotechnological uses. However, information about the ability of arbuscular mycorrhizal fungi (AMF) to affect its biomass accumulation, flower production, and concentration of a.i. under contrasting nutrient availability is still scarce. In the present experiment, we evaluated the role of AMF on growth, flower production, and concentration of bioactive secondary metabolites (hypericin, pseudohypericin, and hyperforin) of H. perforatum under contrasting P availability. AMF stimulated the production of aboveground biomass under low P conditions and increased the production of root biomass. AMF almost halved the number of flowers per plant by means of a reduction of the number of flower-bearing stems per plant under high P availability and through a lower number of flowers per stem in the low-P treatment. Flower hyperforin concentration was 17.5% lower in mycorrhizal than in non-mycorrhizal plants. On the contrary, pseudohypericin and hypericin concentrations increased by 166.8 and 279.2%, respectively, with AMF under low P availability, whereas no effect of AMF was found under high P availability. These results have implications for modulating the secondary metabolite production of H. perforatum. However, further studies are needed to evaluate the competition for photosynthates between AMF and flowers at different nutrient availabilities for both plant and AM fungus.

Quality Characteristics of Wholemeal Flour and Bread from Durum Wheat (Triticum turgidum L subsp. durum Desf.) after Field Treatment with Plant Water Extracts.

The use of selected plant water extracts to control pests and weeds is gaining growing attention in organic and sustainable agriculture, but the effects that such extracts may exert on the quality aspects of durum wheat are still unexplored. In 2014, 5 plant water extracts (Artemisia arborescens, Euphorbia characias, Rhus coriaria, Thymus vulgaris, Lantana camara) were prepared and distributed on durum wheat cv Valbelice to evaluate their potential herbicidal effects. After crop harvesting, the major physicochemical and technological parameters of wholemeal flours obtained from each treatment were measured and compared with those from chemical weeding and untreated controls. A baking test was also performed to evaluate the breadmaking quality. In wholemeal flours obtained after the treatment with plant extracts protein and dry gluten content were higher than in control and chemical weeding. Wholemeal flours obtained after chemical weeding reached the highest Mixograph parameters, and that from durum wheat treated with R. coriaria extract demonstrated a very high α-amylase activity. We concluded that the treatments with plant water extracts may influence many quality traits of durum wheat. This occurrence must be taken into account in overall decisions concerning the use of plant extracts in pest and weed management practice.

The scent of Mare Nostrum: medicinal and aromatic plants in Mediterranean soils.

In the Mediterranean area, the simultaneous occurrence of pedological, climatic and economic constraints often sets a limit on the profitability of agriculture, and farmers are forced to grow a reduced number of species, dealing with a secure-albeit low-market income. The introduction of medicinal and aromatic plants (MAPs) inside the current farming systems could represent a useful means to meet the multifunctional role of agriculture: producing safe food, in respect of the environment, and contributing to the development of rural areas. The study of the relationships between MAPs and the soils in which they may be grown may have two approaches: (1) the evaluation of yield and qualitative response of MAPs to the variation of soil features; and (2) the study of selective recovery of certain elements (toxic and beneficial), and their subsequent release in herbal products. In many MAPs, significant variations of plant characteristics have been ascertained with varying soil traits, and the selective recovery and subsequent release in food of certain elements have been demonstrated. Hence, great attention must be paid to the choice of soil and cropping strategies, to obtain satisfactory yields of high quality and best-priced products, respecting their safety and nutritional value.