Successive harvests affect the aromatic and polyphenol profiles of novel catnip (Nepeta cataria L.) cultivars in a genotype-dependent manner.

Introduction: Catnip (Nepeta cataria L.) produces volatile iridoid terpenes, mainly nepetalactones, with strong repellent activity against species of arthropods with commercial and medical importance. Recently, new catnip cultivars CR3 and CR9 have been developed, both characterized by producing copious amounts of nepetalactones. Due to its perennial nature, multiple harvests can be obtained from this specialty crop and the effects of such practice on the phytochemical profile of the plants are not extensively studied. Methods: In this study we assessed the productivity of biomass, chemical composition of the essential oil and polyphenol accumulation of new catnip cultivars CR3 and CR9 and their hybrid, CR9×CR3, across four successive harvests. The essential oil was obtained by hydrodistillation and the chemical composition was obtained via gas chromatography-mass spectrometry (GC-MS). Individual polyphenols were quantified by Ultra-High-Performance Liquid Chromatography- diode-array detection (UHPLC-DAD). Results: Although the effects on biomass accumulation were independent of genotypes, the aromatic profile and the accumulation of polyphenols had a genotype-dependent response to successive harvests. While cultivar CR3 had its essential oil dominated by E,Z-nepetalactone in all four harvests, cultivar CR9 showed Z,E-nepetalactone as the main component of its aromatic profile during the 1st, 3rd and 4th harvests. At the second harvest, the essential oil of CR9 was mainly composed of caryophyllene oxide and (E)-ß-caryophyllene. The same sesquiterpenes represented the majority of the essential oil of the hybrid CR9×CR3 at the 1st and 2nd successive harvests, while Z,E-nepetalactone was the main component at the 3rd and 4th harvests. For CR9 and CR9×CR3, rosmarinic acid and luteolin diglucuronide were at the highest contents at the 1st and 2nd harvest, while for CR3 the peak occurred at the 3rd successive harvest. Discussion: The results emphasize that agronomic practices can significantly affect the accumulation of specialized metabolites in N. cataria and the genotype-specific interactions may indicate differential ecological adaptations of each cultivar. This is the first report on the effects of successive harvest on these novel catnip genotypes and highlights their potential for the supply of natural products for the pest control and other industries.

Antimicrobial and Antioxidant Properties of Theobroma cacao, Bourreria huanita, Eriobotrya japonica, and Elettaria cardamomum - Traditional Plants Used in Central America.

The search for alternative naturally occurring antimicrobial agents will always continue, especially when emerging diseases like COVID-19 provide an urgency to identify and develop safe and effective ways to prevent or treat these infections. The purpose of this study was to evaluate the potential antimicrobial activity as well as antioxidant properties of commercial samples from four traditional medicinal plants used in Central America: Theobroma cacao, Bourreria huanita, Eriobotrya japonica, and Elettaria cardamomum. Ethanolic extracts were prepared from commercial products derived from the seeds or flowers of these plants. Total phenolics and antioxidant activity were assessed using commercial kits. The cytotoxicity and antiviral activity against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) were evaluated using the XTT colorimetric assay and a SARS-CoV-2 delta pseudoviral model. The half-maximal cytotoxic concentration (CC50) and half-maximal effective concentration (EC50) were used to calculate the therapeutic index (TI). Additionally, the antibacterial activity against Escherichia coli and Staphylococcus epidermidis was tested using a spectrophotometric method. The extracts showed total phenolics in the range of 0.06 to 1.85 nM/µL catechin equivalents, with T. cacao bean extract showing the highest content. The antioxidant activity showed values between 0.02 and 0.44 mM Trolox equivalents. T. cacao bean extract showed the highest antioxidant activity. Most plant extracts showed zero to moderate selective antiviral activity; however, one T. cacao beans sample showed excellent antiviral activity against SARS-CoV-2 with a TI value of 30.3, and one sample of E. japonica showed selective antiviral activity with a TI value of 18.7. Significant inhibition of E. coli and S. epidermidis by an E. japonica ethanolic extract (p<0.001) was observed using a spectrophotometric method that monitors bacterial growth over time. Additionally, ethanolic extracts of E. cardamomum showed significant inhibition of S. epidermidis growth (p<0.001). The results warrant further investigation of the antimicrobial and antioxidant properties of these plant extracts.

Essential oils in combination and their antimicrobial properties.

Essential oils (EOs) have been long recognized for their antibacterial, antifungal, antiviral, insecticidal and antioxidant properties. They are widely used in medicine and the food industry for these purposes. The increased interest in alternative natural substances is driving the research community to find new uses and applications of these substances. EOs and their components show promising activities against many food-borne pathogens and spoilage microorganisms when tested in vitro. In food systems, higher concentrations of EOs are needed to exert similar antibacterial effects as those obtained in in vitro assays. The use of combinations of EOs and their isolated components are thus new approaches to increase the efficacy of EOs in foods, taking advantage of their synergistic and additive effects. The purpose of this review is to provide an overview on the antimicrobial efficacy of these combinations. A survey of the methods used for the determination of the interactions and mechanisms involved in the antimicrobial activities of these combinations are also reported.

Descriptive aroma profiles of fresh sweet basil cultivars (Ocimum spp.): Relationship to volatile chemical composition.

Few studies have linked sensory descriptions of the aroma profiles of fresh, sweet basil varieties with their volatile chemistry. Using a recently developed lexicon for fresh basil, a descriptive panel characterized the aroma profiles of seven basil varieties. Chemical analysis of fresh basil leaves was performed using GC-MS headspace analysis. Analysis of variance probed for differences in the sensory attributes among varieties and principal component analysis (PCA) related the sensory profiles to volatile chemical composition. Three commercial specialty basils, "Queenette Thai" (QT), "Sweet-Dani" (SD) lemon basil, and MC-9 (cinnamon basil) had strong anise, lemon, and cinnamon-like aromas, respectively. These basils were distinguished from breeding lines of traditional Italian sweet basils where SB-22, CB-1, and CB-39 exhibited strong anise-like aroma and SB-17 had strong "general spice" aromas, characteristic of a warm spice blend. The PCA accounted for 58.7% of the variation in the data and characterized the samples in two dimensions: general spice-citrus and cinnamon-like-anise. There was a strong correspondence between the sensory attributes and volatile chemical composition. SD associated with lemon aroma and citral content; QT, CB-1, and CB-39 associated with anise aroma and methyl chavicol; and MC-9 associated with the cinnamon-like aroma, methyl cinnamate. SB-17 and SB-22 associated with general spice aroma and were in close proximity to the spice-like volatiles, 1,8 cineole, and eugenol, associated with clove aroma. We constructed precise sensory/chemical profiles for fresh basil aroma that can be used to guide breeding programs for variety improvement to meet consumer expectations or market demand. PRACTICAL APPLICATION: Sweet basil aroma is due to a complex array of several aromatic volatile compounds. The presence, concentration, and the particular ratios in which these aroma compounds accumulate significantly impact the sensory attributes. Understanding aroma profiles for fresh basil have practical applications in product development, procurement, food preparation, ethnic cuisine, and processing. Plant genetics and breeding of aroma profiles can be used and incorporated in plant improvement programs.

Inter and intra population phenotypic variability of Lippia integrifolia (Verbenaceae) and its natural situation in the west-center of Argentina / Variabilidad fenotípica inter e intra poblacional de Lippia integrifolia (Verbenaceae) y su situación natural en el centro-oeste de Argentina

The species Lippia integrifolia is an aromatic, sub-woody shrub, distributed from Northwest and Central Argentina to Bolivia. It is among the most important native aromatic species. It presents medicinal properties, some of which have been scientifically proven. As an alternative to harvesting, the process of domestication of the species was initiated. The objective of this work was to assess the phenotypic variability based on botanical-taxonomic and morpho-agronomic descriptors and the use of indicators to evaluate its natural situation in the west-center of Argentina. We worked in five wild populations, registering morphological variables, phenology, natural regeneration, herbivory and presence of diseases. L. integrifoliapresents a wide morphological variability, which can be explained with three morphological descriptors. Natural regeneration ́s rate is very low to zero, in four of the sites. The results obtained are of importance to make decisions related to the sustainable use in situ, and to begin a program of domestication of the species.

La especie Lippia integrifolia es un arbusto aromático, sub-leñoso, distribuido desde el noroeste y centro de Argentina hasta Bolivia. Es una de las especies aromáticas nativas más importantes. Presenta propiedades medicinales, algunas de las cuales han sido científicamente probadas. Como alternativa a la cosecha, se inició el proceso de domesticación de la especie. El objetivo de este trabajo fue evaluar la variabilidad fenotípica basada en descriptores botánico-taxonómicos y morfo-agronómicos y el uso de indicadores para evaluar su situación natural en el centro-oeste de Argentina. Trabajamos en cinco poblaciones silvestres, registrando variables morfológicas, fenología, regeneración natural, herviboría y presencia de enfermedades. L. integrifolia presenta una amplia variabilidad morfológica, que puede explicarse con tres descriptores morfológicos. La tasa de regeneración natural es muy baja a cero, en cuatro de los sitios. Los resultados obtenidos son importantes para tomar decisiones relacionadas con el uso sostenible in situ y para comenzar un programa de domesticación de la especie.

A rapid LC/MS/MS method for the analysis of nonvolatile antiinflammatory agents from Mentha spp.

UNLABELLED: Mints (Mentha spp.), aromatic crops grown largely for their essential oils, also are rich sources of nonvolatile antiinflammatory agents. Identification and quantitation of the constituents responsible for their antiinflammatory activity is challenging owing to the lack of suitable chromatographic methodology. In the present research, the simultaneous quantitation of antiinflammatory constituents rosmarinic acid, oleanolic acid, and ursolic acid in mints was attained by using a unique tandem HPLC column system coupled with an electrospray ionization mass detection (MRM mode). The ion mode optimization for rosmarinic acid under negative and triterpenoid acids under positive was achieved by setting 2 time segments in a single run where the polarity mode was switched from negative (0 to 10 min) to positive (10 to 40 min). For the investigated concentration ranges of antiinflammatory agents in mints, good linearities (r² ≥ 0.998) were obtained for each calibration curve. Validation of precision and accuracy for this method showed that intra- and inter-day repeatabilities for all analytes were less than 5.51%, and the recoveries varied from 97.8% to 99.3%. The developed LC/MS/MS assay provides a suitable quality control method for the determination of antiinflammatory constituents in Mentha spp. There is a wide range of diversity in the natural product composition for these acids across the Mentha germplasm collection evaluated. The presence of these antiinflammatory acids in post-distilled mints shows that value-added nutraceutical enriched products can be developed with proper processing and recovery systems in addition to the distillation and capture of the valuable volatile essential oils. PRACTICAL APPLICATION: Results from this research would benefit both commercial farmers growing mint for essential oil and those in the food industry where value-added phytopharmaceutical enriched products can be developed with proper processing, quality control, and recovery systems during mint essential oil distillation.

LC-MS method for the simultaneous quantitation of the anti-inflammatory constituents in oregano (Origanum species).

Oregano (Origanum spp.), a popular herb in western and Middle Eastern cuisine, was reported to show anti-inflammatory activities in vitro and in vivo but without any information as to the compounds responsible, whether the plants were authenticated or only contained true Origanum spp. Using a wide range of botanically authenticated oregano, we were able to show that oregano had anti-inflammatory activity and then using biodirected-guided fractionation, identified the anti-inflammatory agents in oregano as rosmarinic acid, oleanolic acid, and ursolic acid. In this study, we successfully developed an LC-MS (SIM mode) method to achieve coquantitation of these three organic acids with the application of a unique tandem column system. The detection of rosmarinic acid was optimal under negative ion mode of SIM, whereas oleanolic acid and ursolic acid were sensitive to positive ion mode. The simultaneous quantitation was attained by setting two time segments in one run to facilitate the ESI polarity switch. For the investigated analytes romarinic acid, oleanolic acid, and ursolic acid, good linearities (r(2) > 0.999) were obtained for each calibration curve. Validation for this method showed a precision (relative standard deviation) ranging from 4.84 to 6.41%, and the recoveries varied from 92.2 to 100.8% for the three analytes. A quantitative survey of these anti-inflammatory constituents in different oregano species (O. vulgare ssp. hirtum, O. vulgare, and O. syriacum) and chemotypes within the species varied significantly in their accumulation of rosmarinic, oleanolic, and ursolic acids. Significant variation in chemical composition between species and within a species was found.