Plant Material Research Articles

Distinction of chia varieties in vivo and in vitro based on the flow cytometry and rosmarinic acid production.

Flow cytometry has made a significant contribution to the study of several complex fundamental mechanisms in plant cytogenetics, becoming a useful analytical tool to understand several mechanisms and processes underlying plant growth, development, and function. In this study, the genome size, DNA ploidy level, and A-T/G-C ratio were measured for the first time for two genotypes of chia, Salvia hispanica, an herbaceous plant commonly used in phytotherapy and nutrition. This study also evaluated, for the first time by flow cytometry, the capacity to produce organic acids of tissues stained with LysoTracker Deep Red after elicitation with either yeast extract or cadmium chloride. Rosmarinic acid content differed between the two chia varieties treated with different elicitor concentrations, compared with non-elicited plant material. Elicited tissues of both varieties contained a higher content of rosmarinic acid compared with non-elicited cultures, and cadmium chloride at 500 μM was much better than that at 1000 μM, which led to plant death. For both genotypes, a dose-response was observed with yeast extract, as the higher the concentration of elicitor used, the higher rosmarinic acid content, resulting also in better results and a higher content of rosmarinic acid compared with cadmium chloride. This study demonstrates that flow cytometry may be used as a taxonomy tool, to distinguish among very close genotypses of a given species and, for the first time in plants, that this approach can also be put to profit for a characterization of the cytoplasmic acid phase and the concomitant production of secondary metabolites of interest in vitro, with or without elicitation. KEY POINTS: • Genome size, ploidy level, A-T/G-C ratio, and cytoplasm acid phase of S. hispanica • Cytometry study of cytoplasm acid phase of LysoTracker Deep Red-stained plant cells • Yeast extract or cadmium chloride elicited rosmarinic acid production of chia tissues.

Lippia grata Essential Oil Acts Synergistically with Ampicillin Against Staphylococcus aureus and its Biofilm.

Antimicrobial resistance (AMR) presents a global challenge as microorganisms evolve to withstand the effects of antibiotics. In addition, the improper use of antibiotics significantly contributes to the AMR acceleration. Essential oils have garnered attention for their antimicrobial potential. Indeed, essential oils extracted from plants contain compounds that exhibit antibacterial activity, including against resistant microorganisms. Hence, this study aimed to evaluate the antimicrobial and antibiofilm activity of the essential oil (EO) extracted from Lippia grata and its combination with ampicillin against Staphylococcus aureus strains (ATCC 25923, ATCC 700698, and JKD6008). The plant material (leaves) was gathered in Mossoro, RN, and the EO was obtained using the hydrodistillation method with the Clevenger apparatus. The antimicrobial activity of the EO was assessed through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Antibiofilm activity was evaluated by measuring biomass using crystal violet (CV) staining, viable cell counting, and analysis of preformed biofilms. In addition, the synergistic effects of the EO in combination with ampicillin were examined by scanning electron and confocal microscopy. The EO displayed a MIC value of 2.5mg/mL against all tested S. aureus strains and an MBC only against S. aureus JKD6008 at 2.5mg/mL. L. grata EO caused complete biofilm inhibition at concentrations ranging from 10 to 0.312mg/mL against S. aureus ATCC 25923 and 10 to 1.25mg/mL against S. aureus ATCC 700698 and S. aureus JKD6008. In the viable cell quantification assay, there was a reduction in CFU ranging from 1.0 to 8.0 logs. The combination of EO with ampicillin exhibited a synergistic effect against all strains. Moreover, the combination showed a significantly inhibiting biofilm formation and eradicating preformed biofilms. Furthermore, the EO and ampicillin (individually and in combination) altered the cellular morphology of S. aureus cells. Regarding the mechanism, the results revealed that L. grata EO increased membrane permeability and caused significant membrane damage. Concerning the synergy mechanism, the results revealed that the combination of EO and ampicillin increases membrane permeability and causes considerable membrane damage, further inhibiting bacteria synergistically. The findings obtained here suggest that L. grata EO in combination with ampicillin could be a viable treatment option against S. aureus infections, including MRSA strain.

Improving the sustainability and effectiveness of photovoltaic evaporative cooling greenhouse in the Sahel.

Anthropogenic climate change has caused worldwide extreme weather events including droughts, floods and heatwaves. It disproportionately affects developing countries through food insecurity. Greenhouse is important and relevant to the food-energy-water security in many regions. This study investigates the thermal behavior of photovoltaic evaporative cooling greenhouse made with eco-friendly coolers. The cooling potential of local plant materials was assessed under ambient conditions. Experimental thermal data obtained from optimized evaporative cooling system equipped with Hyphaene thebaica fibers (HF-pad) and conventional Celdek pad (C-pad), were used in heat and mass transfer equations to derive the greenhouse cooling performances. Computational fluid dynamics analysis software was used to investigate the refrigerant fluid distribution in the greenhouse. Cooler using HF-pad allows to keep the microclimate below 25°C, with maximum moisture rate up to 80%, under harsh ambient conditions (temperature: 30-45°C, humidity: 10-15%). HF-pad had the highest cooling coefficient of performance (COP = 9 against 6 for C-pad), the best cost to efficiency ratio (CER = 5; 4 times less than C-pad) and the lowest outlet temperature (20.0°C). Due to higher outlet air velocity (1.116m/s against 0.825m/s for HF-pad), C-pad cooler spread cool air (20.5°C) up to 1.25m farther than its counterpart, creating higher pressure in the atmosphere (1.42Pa against 0.71Pa), with 2 times turbulent kinetic energy (0.014J/kg). HF-pad presented cooling performances that compete with conventional pads. Moreover, optimization of HF-pad frame engineering and the technology scaling up to industrial level can allow better thermal and economic performances.

An Inhibitor-Monitorable Single-Tube Duplex Quantitative Real-Time PCR Assay for the Detection of 'Candidatus Liberibacter asiaticus'.

Huanglongbing (HLB) is a citrus infectious disease caused by 'Candidatus Liberibacter' spp. Recently, it has begun to spread rapidly worldwide, causing significant losses to the citrus industry. Early diagnosis of HLB relies on quantitative real-time PCR assays. However, the PCR inhibitors found in the nucleic acid extracted from plant materials pose challenges for PCR assays because they may result in false-negative results. Internal standard (IS) can be introduced to establish a single-tube duplex PCR for monitoring the influence of the PCR inhibitor, but it also brings the risk of false-negative results because the amplification of IS may compete with the target. To solve this problem, we proposed a mutation-enhanced single-tube duplex PCR (mSTD-PCR) containing IS with mutant-type primers. By introducing the 3'-terminal mutation in the primer of IS to weaken its amplification reaction and its inhibition of 'Candidatus Liberibacter asiaticus' (CLas) detection, the sensitivity and quantitative accuracy of CLas detection will not be affected by IS. In evaluating the sensitivity of CLas detection using simulation samples, the mSTD-PCR showed consistent sensitivity at 25 copies per test compared with the single-plex CLas assay. The detection result of 30 leaves and 30 root samples showed that the mSTD-PCR could recognize false-negative results caused by the PCR inhibitors and reduce workload by 48% compared with the single-plex CLas assay. Generally, the proposed mSTD-PCR provides a reliable, efficient, inhibitor-monitorable, quantitative screening method for accurately controlling HLB and a universal method for establishing a PCR assay for various pathogens.

Pinecone-Inspired Humidity-Responsive Paper Actuators with Bilayer Structure

Many plant materials in nature have the ability to change their shape to respond to external stimuli, such as humidity or moisture, to ensure their survival or safe seed release. A well-known example for this phenomenon is the pinecone, which is able to open its scales at low humidity due to the specific bilayer structures of the scale. Inspired by this, we developed a novel humidity-driven actuator based on paper. This was realized by the lamination of untreated paper made from eucalyptus fibers to a paper–carboxymethyl cellulose (CMC) composite. As observed, the hygroexpansion of the composite can be easily controlled by the amount of CMC in the impregnated paper sheet, which, thus, controls the morphologic deformation of the paper bilayer. For a more detailed understanding of these novel paper soft robots, we also studied the dynamic water vapor adsorption, polymer distribution and hygroexpansion of the paper–polymer composites. Finally, we applied a geometrically nonlinear finite element model to predict the bending behavior of paper bilayers and compared the results to experimental data. From this, we conclude that due to the complexity of structure of the paper composite, a universal prediction of the hygromorphic behavior is not a trivial matter.

Impact of jasmonates, salicylic acid, and fungal elicitor on the health of <i>Hippeastrum hybridum</i> bulbs achieved by <i>in vitro</i> procedure

Production of high-quality vigorous plant materials obtained by micropropagation requires not only a good regeneration procedure but also efficient ways to enhance their post-transplanting ability to cope with external environmental factors. There is increasing interest in <i>Hippeastrum hybridum</i> on the horticultural market. However, the traditional method of cultivation using seeds and bulbs does not meet the growing demand and requirements of available priming procedures, thus leading to a search for more effective methods of reproduction. The aim of the study was to assess the morphogenetic abilities of bulb and flower explants for regeneration and investigate whether the enrichment of the multiplication process by exposure to elicitors will improve the health of the obtained plants through faster synthesis of phytoalexin. The study revealed that high regeneration efficiency can be obtained by using twin-scales, peduncles, and receptacles. Over 76% of explants were capable of bulblet induction and the micropropagation rates were 2.3, 2.7, and 5.0, respectively. At the rooting stage, the use of regulator-free medium was required, yielding a high percentage of rooted shoots of over 90% (shoots obtained on twin-scales and peduncles). The materials obtained <i>in vitro</i> did not differ morphologically from the initial materials. However, it was noted that, after exposure to the <i>Phoma narcissi</i> fungal elicitor or to jasmonic acid (JA) and jasmonic acid methyl ester (MeJA), the <i>in vitro</i>-derived bulbs were able to synthesize phytoalexin with higher efficiency than the untreated ones. Therefore, the described methods can be useful for <i>H. hybridum</i> multiplication. Moreover, the enrichment of the multiplication process with the stage of exposure to elicitors ensures initial immunity of <i>H. hybridum</i> to the pathogen <i>Phoma narcissi</i>, which can be used as a priming procedure.

Three new species of Teunia (Cryptococcaceae, Tremellales) identified through phenotypic and phylogenetic analyses

Teunia, belonging to the family Cryptococcaceae of the order Tremellales, is a genus of plant-inhabiting fungi distributed across the globe. Its members form associations with different plant parts, including flowers, fruits, leaves, seeds, and twigs. Recent efforts have aimed to explore the diversity of Teunia in China, however, many geographical regions have not yet been explored. In this study, we included results of five Teunia yeast strains that were isolated from plant materials collected in Fujian, Guizhou and Henan provinces, with descriptions, illustrations, and phylogenetic analyses of three new species: T. acericola, T. mussaendrae isolated from leaf surfaces in Fujian, Guizhou and Henan Provinces, and T. qingyuanensis obtained from rotting wood in Fujian Province.

Variation in survival, growth and stem straightness in Eucalyptus urophylla provenances in the Southern Highlands region, Tanzania

Lack of quality planting materials has significantly limited productivity and quality of commercial forestry plantations in Tanzania. A provenance/progeny trial of Eucalyptus urophylla was established to test performance in order to select the best planting materials for future plantation activities. A complete randomised block design was used whereby 30 families from 8 provenances within 6 replications were tested. At 13 years tree survival, growth (diameter at breast height and height) and stem straightness were assessed. The results indicate that there were highly significant differences (p < 0.05) among provenances and families in survival, height, breast height diameter (DBH) and stem straightness. The overall survival ranged from 79.0% to 96.2%; height ranged between 24.9 and 32.5 m; and DBH ranged from 18.7 to 24.5 cm. Overall, results from this study show that provenances Alassannaru, Elun kirpas, Nesunhuhun and Nakana ulam have better growth performance and stem form than others. These results provide valuable information on the growth performance of different provenances and families of E. urophylla. The provenances and families selected with best performance can be used in developing improved seeds for plantation establishment and/or selection of plus trees for vegetative propagation as candidate clones for a clonal testing programme in Tanzania.

Behavior of Thiamethoxam and Clothianidin in Young Oilseed Rape Plants before Flowering, Monitored by QuEChERS/LC–MS/MS Protocol

Behavior of Thiamethoxam and Clothianidin in Young Oilseed Rape Plants before Flowering, Monitored by QuEChERS/LC–MS/MS Protocol

Phenol content, potential antioxidant and anti-urolithic effects of fruit and leaf extracts from Algerian Capparis spinosa L.

Background: Ethnobotanical studies have historically documented the traditional medicinal use of Caper (Capparis spinosa L.) in treating kidney stones and other chronic renal ailments. Aims: This study aimed to evaluate the phenolic content, antioxidant capacity, and potential inhibitory effects of Capparis spinosa L. fruit and leaf extracts on calcium oxalate nucleation and aggregation. Material and Methods: Plant material was collected from the Tessala Mountains in Algeria. Total phenolic content was determined using the Folin-Cioclateu method, while in vitro antioxidant activity was assessed via the DPPH assay. In vitro anti-urolithic testing involved the use of turbidimetry in kinetic experiments to evaluate calcium oxalate nucleation and aggregation. Results: The IC50 values for antioxidant activity against DPPH were 8.67 mg/mL for fruit extracts and 0.57 mg/mL for leaf extracts. Furthermore, the investigated extracts exhibited a concentration-dependent inhibition of calcium oxalate crystal nucleation and aggregation. At the highest concentrations of leaf and fruit extracts, the corresponding inhibition rates were 74.47% and 66.06% for the nucleation test and 67.75% and 54.19% for the aggregation assay, respectively. Conclusions: These findings substantiate the traditional usage of Capparis spinosa L. in managing urinary lithiasis, suggesting its potential application as either a preventive measure or a therapeutic intervention for urinary stone formation. Keywords: Antioxidant, Calcium oxalate, Capparis spinosa L., Urolithiasis, Polyphenols.

Chemical Management Strategies of Pimelea trichostachya Lindl. Using Pre- and Post-Emergence Herbicides

Pimelea trichostachya Lindl. is a native Australian forb responsible for livestock poisoning and reducing the productivity and sustainability of grazing enterprises. This study was conducted as a pot trial under controlled conditions to investigate an effective chemical management strategy for P. trichostachya, a method that did not leave standing dead plant material, as such material can also be toxic to grazing cattle. Three herbicides, including one pre-emergence (tebuthiuron) and two post-emergence herbicides (2,4-D and metsulfuron-methyl), were tested in pot trials for their efficacy on P. trichostachya. Results showed that tebuthiuron applied as either a granular (10% active ingredient, a.i.) or pelleted (20% a.i.) form efficiently reduced the emergence of P. trichostachya seedlings. Although some seedlings emerged, they perished within 7 days post treatment, leaving no residual plant matter. Testing now needs to be undertaken under field conditions to validate the findings within vegetation communities where potential non-target impacts need to be accounted for as well. The post-emergence application of 2,4-D and metsulfuron-methyl demonstrated that the highest efficacy and reduced application rates were achieved by treating earlier growth stages (i.e., seedlings) of P. trichostachya plants. In addition, the amount of toxic dead plant material was minimized due to the faster degradation of these small plants. These findings offer practical, cost-effective solutions for sustaining grazing lands from P. trichostachya challenges.

Photodegradation of cannabidiol (CBD) and Δ9-THC in cannabis plant material.

Δ9-THC, the psychotropic cannabinoid in Cannabis sativa L., for many years has been the focus of all the pharmacological attention as the main promising principle of the plant. Recently, however, cannabidiol (CBD) has brought a sudden change in the scenario, exponentially increasing the interest in pharmacology as the main non-psychotropic cannabinoid with potential therapeutic, cosmetical and clinical applications. Although the reactivity of CBD and Δ9-THC has been considered, little attention has been paid to the possible photodegradation of these cannabinoids in the vegetal matrix and the data available in the literature are, in some cases, contradictory. The aim of the present work is to provide a characterization of the photochemical behaviour of CBD and Δ9-THC in three cannabis chemotypes, namely I (Δ9-THC 2.50%w/w), II (CBD:Δ9-THC 5.82%w/w:3.19%w/w) and III (CBD 3.02%w/w).

Анализ распространения фитоплазм почернения древесины и золотистого пожелтения на виноградниках Краснодарского края

The purpose of research is to study the spread of phytoplasma infection in the vineyards of the Krasnodar Region using the PCR method. The object of the study is grape plants of various varieties with external symptoms of phytoplasma infection. The material for total DNA extraction was symptomatic leaves (their veins and petioles) collected from plantings of Shiraz, Chardonnay, Cabernet Sauvignon, Saperavi, Mizar, Moldova, Augustine, Pinot Blanc, Riesling, and Aligote varieties. DNA extraction was carried out using a buffer based on the cationic detergent CTAB (cetyltrimethylammonium bromide), according to the protocol recommended by EPPO (European plant protection organization) for the isolation of phytoplasmas from grape plant material. Sampling was carried out in industrial vineyards of the Krasnodar Region in 9 different geographical locations of the Novorossiysk, Temryuk and Anapa Regions. DNA was isolated from symptomatic leaves according to the protocol recommended by EPPO (European plant protection organization). Determination of the presence of phytoplasma infection was carried out by real-time PCR on a Quant Studio 5 amplifier using a commercial kit designed to detect phytoplasmas – Candidatus Phytoplasma solani and Candidatus Phytoplasma vitis (Synthol) and a test system recommended by EPPO. Using a kit produced by Synthol, 239 samples were analyzed, including 12 rechecked with markers recommended by EPPO. As a result of the analysis, it was found that DNA of Candidatus Phytoplasma solani was present in 113 samples studied. DNA from the phytoplasma Candidatus Phytoplasma vitis, which causes golden yellowing of leaves, was not detected in any of the analyzed samples.

Study of the differences in collection scope of raw materials of biomass CHP plants caused by regional factors

Combined heat and power (CHP) plants fueled by biomass can collect and utilize waste straw resources in a productive way. This paper considers the impact of regional factors on biomass energy potential and the energy needs of the population, so as to study the differences in construction of biomass CHP plants and the collection scope of raw materials, and proposes evaluating suitability for biomass energy development based on scope of resource collection. Taking five counties in China as its study areas, this paper assesses biomass energy potential. A topology system of biomass CHP plants has been reasonably established in different counties through ArcGIS, the required installed capacity has been calculated according to the number of persons served by such plants. Finally, the collection length and corresponding value range of raw materials of CHP plants along roads has been obtained based on biomass energy potential and energy demand. The result shows that the differences in area, straw yield and biomass fuelization rate depending on regions have a great impact on biomass energy potential, while the residue-to-product ratio of straw and biomass calorific value have less of an impact. When the biomass energy per capita of a region reaches 9.75GJ/person, it is suitable for biomass energy development. The installed capacity in the biomass CHP plant system of each study area is mostly within the scope of 3–59 MW, and the collection length of corresponding biomass resources of such plants along roads is mostly within the scope of 5.09–25.23 km.

Does the Invasive Heracleum mantegazzianum Influence Other Species by Allelopathy?

Heracleum mantegazzianum is an invasive species in middle Europe. The mode of action of its invasiveness is still not known. Our study focuses on observation of potential allelopathic influence by the production and release of phytochemicals into its environment. Plant material was collected four times within one season (April, May, June, July 2019) at locality Lekárovce (eastern Slovakia) for comparison of differences in composition and potential allelopathy. Water extracts from collected samples were used for different biological assays. The total phenols and flavonoids were determined spectrophotometrically. The profile and content of phenolic components, including coumarins, were determined by two techniques of liquid chromatography along with in vitro evaluation of the free radical scavenging activity of extracts (DPPH, Hydroxyl, Superoxide, and FRAP). The changes in composition in extracts in different seasonal periods were evident as well as potential phytotoxic activity in some concentrations on specific model plants. The slight antioxidant activity was noted. The invasiveness of the current species could be supported by the excretion of its phytochemicals into its surroundings and by different modes of action influencing living organisms in its environment.

QTL Mapping and Candidate Gene Mining for Stem Diameter Using Genetic Basis of Cultivated Soybean and Wild Soybean

Soybean (Glycine max) is a vital food crop, serving as a major source of high-quality protein for human and animal consumption. Stem diameter is one of the primary determinants of the stem lodging resistance of a given plant, but there has been relatively little research to date focused on genes associated with this trait. To address this gap in the literature, 207 chromosome segment substitution lines (CSSLs) were generated in the present study through the crossing and backcrossing of the improved Suinong14 and the wild ZYD00006 soybean varieties. These CSSLs were then used for the mapping of quantitative trait loci (QTLs) associated with stem diameter in two-year field planting materials, leading to the identification of nine QTLs. Whole genome resequencing, RNA-seq, and qPCR were then used to evaluate candidate genes associated with stem diameter within these QTL intervals, ultimately leading to the selection of Glyma.04G004100 as a stem diameter-related gene. Subsequent qPCR analyses revealed that Glyma.04g004100 was upregulated in soybean plants with larger stem diameters, and haplotype analyses yielded results consistent with these stem diameter data in the population used to conduct this study. In summary, a series of QTLs associated with stem diameter were identified in the present study, resulting in the establishment of Glyma.04g004100 as a stem diameter-related gene. Together, these results offer a theoretical foundation for the future molecular-assisted breeding of lodging-resistant soybean varieties, and future functional research focused on Glyma.04g004100 may elucidate the molecular mechanisms and key signaling networks involved in soybean stem development.

In vitro microrhizome induction in Acorus calamus L., a commercially important aromatic medicinal plant

Acorus calamus L., is a leading aromatic medicinal plant that produces pungent aromatic rhizomes that are valued worldwide as an important herbal medicine and is one of the main ingredients in several polyherbal formulations used for neurological and metabolic disorders. The present investigation aims to develop an efficient protocol for in vitro microrhizome induction in A. calamus for the large-scale production of disease-free planting material for commercial purposes. In vitro derived shoots were initiated on MS medium supplemented with different concentrations of sucrose alone (3–10 %) and different concentrations of sucrose (6 % and 7 %) with varying concentrations of BAP alone (0.5–2 mg/L) and combinations with IAA (0.5 and 1 mg/L) and NAA (0.5 and 1 mg/L) were carried out for the microrhizome induction experiments. In different concentrations of sucrose used, healthy and disease-free microshoots of A. calamus were obtained in MS media supplemented with 7 % sucrose followed by 6 % sucrose. The highest shoot length (24.79 ± 0.03 cm) and microrhizome size (4.98 ± 0.03 cm length and 399.60 ± 0.37 mg fresh weight) were obtained in MS solid medium supplemented with 1 mg/L BAP and 0.5 mg/L NAA with 7 % sucrose followed by the same hormone concentration with 6 % sucrose (shoot length-23.68 ± 0.03 cm, microrhizome length- 4.68 ± 0.03 cm and fresh weight of microrhizome-376.60 ± 0.57 mg). The developed protocol can be used for large-scale production of disease-free propagules without rooting and acclimatization and enhance the production of true-to-type planting material.

Combined cytogenetic and molecular methods for taxonomic verification and description of Brassica populations deriving from different origins

Agriculture faces great challenges to overcome global warming and improve system sustainability, requiring access to novel genetic diversity. So far, wild populations and local landraces remain poorly explored. This is notably the case for the two diploid species, Brassica oleracea L. (CC, 2n=2x=18) and B. rapa L. (AA, 2n=2x=20). In order to explore the genetic diversity in both species, we have collected populations in their centre of origin, the Mediterranean basin, on a large contrasting climatic and soil gradient from northern Europe to southern sub-Saharan regions. In these areas, we also collected 14 populations belonging to five B. oleracea closely related species. Our objective was to ensure the absence of species misidentification at the seedling stage among the populations collected and to describe thereafter their origins. We combined flow cytometry, sequencing of a species-specific chloroplast genomic region, as well as cytogenetic analyses in case of unexpected results for taxonomic verification. Out of the 112 B. oleracea and 154 B. rapa populations collected, 103 and 146, respectively, presented a good germination rate and eighteen populations were misidentified. The most frequent mistake was the confusion of these diploid species with B. napus. Additionally for B. rapa, two autotetraploid populations were observed. Habitats of the collected and confirmed wild populations and landraces are described in this study. The unique plant material described here will serve to investigate the genomic regions involved in adaptation to climate and microbiota within the framework of the H2020 Prima project ‘BrasExplor’.

Elderberry Leaves with Antioxidant and Anti-Inflammatory Properties as a Valuable Plant Material for Wound Healing

Elderberry Leaves with Antioxidant and Anti-Inflammatory Properties as a Valuable Plant Material for Wound Healing

Oregano and thyme by-products of olive oil aromatization process with microwave assisted extraction as a rich source of bio-active constituents

IntroductionProcessing of Medicinal Aromatic Plants (MAPs) results in the production of a significant amount of by-products, which are not commercially exploitable. Towards this direction, we studied extensively the by-products of oregano and thyme, remaining after the aromatization of olive oils with microwave assisted extraction (MAE). The purpose of the study was the exploitation of the “wastes” of these two economically significant herbs of Greece, for the potential development of innovative bioactive products.MethodsHence, superior and inferior quality plant material from Origanum vulgare subsp. hirtum and Thymus vulgaris, were extracted with extra virgin olive oil using MAE. For the evaluation of raw plant material, beside the characterization of the essential oils (EOs), the hydroalcoholic extracts of superior and inferior plant material were afforded by ultrasound assistant extraction (UAE). In addition, the remaining plant material after the flavoring of olive oil by MAE, was extracted with c-Hex, MeOH, H2O:MeOH using UAE. All the extracts were evaluated for their DPPH free radical scavenging activity and total phenolic content (TPC) as well as their chemical profile was investigated by HPTLC. In parallel, the EOs, the olive oils and the c-Hex extracts were analyzed by GC–MS and Headspace Solid Phase Microextraction (HS-SPME)-GC–MS.Results and DiscussionThe results showed that the composition of the EOs and the volatile fraction of the olive oil extracts were similar for the superior quality material whereas for the inferior the composition of the volatile fraction of olive oil extracts was not analogous to the respective EOs. GC–MS analyses of oregano and thyme by-products revealed the presence of carvacrol, thymol, γ-terpinene and p-cymene among the major constituents. Moreover, the hydroalcoholic extracts obtained from the plant material remaining after olive oil flavoring with MAE showed similar phenolic content and scavenging activity with the hydroalcoholic extracts of the corresponding raw plant materials underlying their potent use in the preparation of high-added value products such as nutraceuticals and cosmeceuticals as well as enriched animal nutrition products.