Inter and intra population phenotypic variability of Lippia integrifolia(Verbenaceae) and its natural situation in the west-center of Argentina

The species Lippia integrifoliais 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.

Rotational analysis of naphthol-aromatic ring complexes stabilized by electrostatic and dispersion interactions

For complexes involving aromatic species, substitution effects can influence the preferred geometry.

Light intensities alter growth and essential oil of patchouli under shade nets

ABSTRACT: Pogostemon cablin (Blanco) Benth. is an aromatic species popularly known as patchouli. The essential oil rich in patchoulol extracted from leaves is used by the pharmaceutical industries. The objective was to investigate the effects of shade nets and shading intensities on P. cablin growth, anatomy, chemical composition and essential oil content. The experiment was conducted with two types of shade nets (black and Aluminet), three light intensities (30, 50, and 70% shading) and full sun. The different light intensities influenced the growth and the essential oil yield, and chemical composition. Patchouli plants grown in an environment with shading showed higher values for the leaf, stem, root ant total dry weights compared to full sun. At 50% of shading, Aluminet provided gain in stem and total dry weights. Aluminet and black net at 50 and 70% of shading enhance essential oil yield. Patchoulol and pogostol contents were higher under full sun, and, black net and Aluminet at 50% shading. The environment for patchouli cultivation can be improved by use shade nets, especially with Aluminet at 50% of shading.

In vitro Microrhizome Induction and Essential Oil Production from Aromatic Ginger Kaempferia galanga : An Economically Important Medicinal Herb

Kaempferia galanga L. or ‘aromatic ginger’ is a stem-less herb in Zingiberaceae having different pharmacological properties like antioxidant, antimicrobial, nemeticidal, vasorelaxant and wound healing activity. The plant is generally a vegetatively propagated annual herb; its conservation using conventional methods takes more time to get sufficient amount of planting materials for commercial cultivation. Micropropagation by in vitro methods helps to overcome the present demand for this high sought medicinal and aromatic species. At present the concern on in vitro propagation is directed to rhizome or storage organ induction for productive acclimatization and to reduce the injury during transportation. Microrhizomes are the small rhizomes developed in in vitro conditions and its induction is an effective biotechnological tool for the production of quality planting materials as they are genetically stable and disease free. The present study is discussing the role of silver nitrate (AgNO3) along with sucrose in in vitro microrhizome induction in K. galanga for the first time. MS medium fortified with 2.0 mgl-1 AgNO3 along with 6% (w/v) sucrose produced maximum amount of microrhizomes i.e., 4.52±0.11 g after 3 months that increased to 5.70±0.20 g in six months of harvesting. Here we also reports the comparative analysis of chemical constituents in the essential oil of in vivo rhizomes and in vitro microrhizome through GC-MS analysis that further reveals the superior characteristics of the microrhizomes in terms of the bioactive components ethyl p-methoxy cinnamate and ethyl cinnamate, the esters that contribute the nematicidal, antituberculosis, anti-inflammatory, antifungal and larvicidal properties to the oil. This protocol for in vitro microrhizome induction can be used for the commercial production of rhizomes and essential oil in K. galanga and the outcome of this study can be further used for mass production of pathogen-free microrhizomes and conservation for its sustainable utilization of the species.

Effect of Environmental Factors on Plectranthus Neochilus Volatile Composition: A GC-MS-Based Metabolomics Approach

Plectranthus neochilus Schltr. is an aromatic species, commonly used for digestive, antispasmodic, and analgesic purposes. Although many studies have reported the chemical composition of its essential oil, variations in the volatile profile were observed, which may be due to multiple factors linked to growth and field conditions. In order to detect metabolic variations in this species, we employed a GC-MS-based untargeted metabolomics approach analyzing samples of four P. neochilus individuals collected over a year. From all analyses, 24 mass features were detected and 21 were identified according to their respective chromatographic peaks. All features varied among samples, particularly (2E)-hexenal, 3-octanone and δ-3-carene, which showed the highest coefficient of variation percentage in our study. Although the four individuals presented the same peaks in the chromatograms, significant differences in the intensity of specific mass features were detected between individuals throughout the year. Time of sampling did not affect P. neochilus volatile composition; the chemical profile remained constant throughout the day. Seasonal trends were observed for the species. Winter months coincided with a drop in the intensity of most components. Air temperature showed a positive correlation with some feature intensities, while myrcene and α-thujene resulted in a positive and a negative correlation with rainfall, respectively. This study was the first attempt to correlate metabolic variation and environmental factors in P. neochilus. Our approach was successful in identifying the composition and variation of the headspace volatiles of P. neochilus leaves.

Occurrence of Double Bond in π-Aromatic Rings: An Easy Way to Design Doubly Aromatic Carbon-Metal Structures

A chemical bonding of several metallabenzenes and metallabenzynes was studied via an adaptive natural density partitioning (AdNDP) algorithm and the induced magnetic field analysis. A unique chemical bonding pattern was discovered where the M=C (M: Os, Re) double bond coexists with the delocalized 6c-2e π-bonding elements responsible for aromatic properties of the investigated complexes. In opposition to the previous description where 8 delocalized π-electrons were reported in metallabenzenes and metallabenzynes, we showed that only six delocalized π-electrons are present in those molecules. Thus, there is no deviation from Hückel’s aromaticity rule for metallabenzynes/metallabenzenes complexes. Based on the discovered bonding pattern, we propose two thermodynamically stable novel molecules that possess not only π-delocalization but also retain six σ-delocalized electrons, rendering them as doubly aromatic species. As a result, our investigation gives a new direction for the search for carbon-metal doubly aromatic molecules.

The Relation between Drying Conditions and the Development of Volatile Compounds in Saffron (Crocus sativus)

Saffron is derived from the stigmas of the flower Crocus sativus L. The drying process is the most important post-harvest step for converting C. sativus stigmas into saffron. The aim of this review is to evaluate saffron’s post-harvest conditions in the development of volatile compounds and its aroma descriptors. It describes saffron’s compound generation by enzymatic pathways and degradation reactions. Saffron quality is described by their metabolite’s solubility and the determination of picrocrocin, crocins, and safranal. The drying process induce various modifications in terms of color, flavor and aroma, which take place in the spice. It affects the aromatic species chemical profile. In the food industry, saffron is employed for its sensory attributes, such as coloring, related mainly to crocins (mono-glycosyl esters or di-glycosyl polyene).

Comparative Chemical Profiles and Phytotoxic Activity of Essential Oils of Two Ecospecies of Pulicaria undulata (L.) C.A.Mey

The Asteraceae (Compositae) family is one of the largest angiosperm families that has a large number of aromatic species. Pulicaria undulata is a well-known medicinal plant that is used in the treatment of various diseases due to its essential oil (EO). The EO of both Saudi and Egyptian ecospecies were extracted via hydrodistillation, and the chemical compounds were identified by GC–MS analysis. The composition of the EOs of Saudi and Egyptian ecospecies, as well as other reported ecospecies, were chemometrically analyzed. Additionally, the phytotoxic activity of the extracted EOs was tested against the weeds Dactyloctenium aegyptium and Bidens pilosa. In total, 80 compounds were identified from both ecospecies, of which 61 were Saudi ecospecies, with a preponderance of β-pinene, isoshyobunone, 6-epi-shyobunol, α-pinene, and α-terpinolene. However, the Egyptian ecospecies attained a lower number (34 compounds), with spathulenol, hexahydrofarnesyl acetone, α-bisabolol, and τ--cadinol as the main compounds. The chemometric analysis revealed that the studied ecospecies and other reported species were different in their composition. This variation could be attributed to the difference in the environmental and climatic conditions. The EO of the Egyptian ecospecies showed more phytotoxic activity against D. aegyptium and B. pilosa than the Saudi ecospecies. This variation might be ascribed to the difference in their major constituents. Therefore, further study is recommended for the characterization of authentic materials of these compounds as allelochemicals against various weeds, either singular or in combination.

Advanced Chemophenetic Analysis of Essential Oil from Leaves of Piper gaudichaudianum Kunth (Piperaceae) Using a New Reduction-Oxidation Index to Explore Seasonal and Circadian Rhythms

The aromatic species Piper gaudichaudianum Kunth (Piperaceae) is widely used in Brazil for medicinal and ritualistic applications. In the current study, chemophenetic patterns were realized across season and circadian rhythm based on the chemical profile of essential oils (EOs) from leaves. Hydrodistilled essential oils were analyzed by GC-MS and GC-FID, and a new calculation of metabolite oxidation level, averaged for each individual molecule component of the EO, was used to explore the patterns of metabolism/biosynthesis. This new index used an intermediate calculation, the ‘weighted average redox standard’ (SRO), to enable a value for mixtures of metabolites to be generated, the ‘general mixture redox index’ (GMOR). The indices were subjected to a proof-of-concept approach by making comparison to outcomes from multivariate analyses, i.e., PCA and HCA. Chemical analysis demonstrated that the essential oils were dominated by sesquiterpenes, constructed of 15 classes of compound (C-skeletons), and 4 C-skeletons were recognized in the monoterpene group, giving a total of 19. The variation of chemical profiles was distinct at different phenological stages, but stronger chemical variation was evident between day and night as compared to season. Furthermore, due to comprehensive sampling across different regions, nine chemotypes were recognized, including those previously reported. The SRO and GMRO indices demonstrate that phenological variation of chemistry is mainly an outcome of redox fluctuations in terpene biosynthesis, changing from day to night. These indices also corroborate that chemical diversity is increased with oxidative metabolism. Lastly, the current study demonstrates pronounced phenotypic plasticity in P. gaudichaudianum, which makes it a suitable candidate to help further our understanding of chemophenetics and chemical ecology.

Analysis of Local and Global Aromaticity in Si3C5 and Si4C8 Clusters. Aromatic Species Containing Planar Tetracoordinate Carbon

The minimum energy structures of the Si3C5 and Si4C8 clusters are planar and contain planar tetracoordinate carbons (ptCs). These species have been classified, qualitatively, as global (π) and local (σ) aromatics according to the adaptive natural density partitioning (AdNDP) method, which is an orbital localization method. This work evaluates these species’ aromaticity, focusing on confirming and quantifying their global and local aromatic character. For this purpose, we use an orbital localization method based on the partitioning of the molecular space according to the topology of the electronic localization function (LOC-ELF). In addition, the magnetically induced current density is analyzed. The LOC-ELF-based analysis coincides with the AdNDP study (double aromaticity, global, and local). Moreover, the current density analysis detects global and local ring currents. The strength of the global and local current circuit is significant, involving 4n + 2 π- and σ-electrons, respectively. The latter implicates the Si-ptC-Si fragment, which would be related to the 3c-2e σ-bond detected by the orbital localization methods in this fragment.