Aromatic Species Research Articles

The Effect of Salinity and Drought on the Essential Oil Yield and Quality of Various Plant Species of the Lamiaceae Family (Mentha spicata L., Origanum dictamnus L., Origanum onites L.)

Mentha spicata L., Origanum dictamnus L., and Origanum onites L. are aromatic plants that produce very important essential oils. They are considered model plants with beneficial health properties due to their antioxidant content. Enhancing the yield while maintaining the quality of essential oil is of significant commercial importance. Salinization and drought cause various effects on the yield and quality of the bioactive constituents in essential oil. By assessing the response of these plants and their secondary metabolites accumulation to different salt stress and irrigation levels, this study aims to gain insights into how plants adapt to and cope with salinity and drought. A pot experiment was conducted in the spring of 2020 to assess the effect of salinity and drought stress on the growth and essential oils content of the three aromatic plant species mentioned above. The soil mixture used was perlite and peat in a ratio of 1:1:6, while four salinity treatments (25, 50, 100, and 150 mΜ NaCl) and two levels of irrigation were applied (100% and 50%). Salinity significantly affects total chlorophyll concentration especially in higher concentrations (100 and 150 mM) in M. spicata plants, especially under 50% soil water irrigation. Under the same conditions, M. spicata contained the higher proline concentration, which was significantly greater than that in O. dictamnus and O. onites. Similar variations of malondialdehyde and hydrogen hyperoxide were revealed among the three species, with significantly higher values in M. spicata when subjected to both excess salinity and drought conditions. The major compounds identified in M. spicata were carvone, in O. dictamnus carvacrol, and p-cymene and in O. onites carvacrol. It is important to highlight that O. onites had the highest concentration of essential oil, and that the concentration increased with the increase of NaCl. This suggests that the presence of NaCl in the soil may have a stimulating effect on the production of essential oil in O. onites. However, it is plausible that the stress caused by NaCl triggers a physiological response in O. onites, leading to increased production of essential oil. This could be a protective mechanism to enhance the plant’s resistance to the stressor. Overall, O. onites and O. dictamnus appeared to be more resistant to these stress conditions than M. spicata, since they maintained their growth and essential oil quality indicators at higher levels. These two species possess mechanisms that prevent or minimize lipid peroxidation, thus protecting their cell membranes and maintaining their ultrastructure integrity.

Essential oils from Mediterranean aromatic plants Artemisia herba-alba, Artemisia absinthium and Mentha longifolia to improve blueberry shelf life

The Mediterranean Basin is particularly rich in aromatic plants with essential oils whose composition and properties are still to be investigated. The aims of this work were to: investigate the chemical composition of essential oils from three typical Spanish aromatic species: Artemisia herba-alba, Artemisia absinthium and Mentha longifolia; evaluate the antifungal potential of essential oils against seven plant pathogenic and postharvest fungi; analyse the effectiveness of the Mentha longifolia essential oil in extending the blueberry fruit shelf life. The main compounds for the Artemisia herba-alba essential oil were camphor (29.8%), trans-thujone (22%), 1,8-cineole (14.5%) and cis-thujone (10.8%). In the A. absithium essential oil, they were cis-cryshanthemyl acetate (35.4%), cis-β-epoxiocimene (36%) and trans-β-epoxiocimene (10.4%). α-Terpineol acetate (32.6%), pulegone (14.2%) and 8-acetoxy carvotanacetone (10.3%) were the most important molecules in the obtained composition of the Mentha longifolia essential oil. Different bioassays were performed at the 300 μg/mL and 600 μg/mL doses using the distinct essential oils in potato dextrose agar culture medium. The Artemisia herba-alba and Artemisia absinthium essential oils at 300 μg/mL were not very effective. The Mentha longifolia essential oil strongly inhibited mycelial growth at the two tested doses, but it totally inhibited the growth of Curvularia hawaiiensis, Fusarium nygamai and Verticilliun dahliae at 600 μg/mL. The blueberries coated with the Mentha longifolia essential oil solution obtained a statistically higher percentage of healthy fruit than the control. They could be considered an ecofriendly alternative for postharvest treatment, and for maintaining the quality and turgidity of these berries during storage.

Analysis of aromatic carboxylic acid and calcium salt couples with gas chromatography-mass spectrometry: Implications and comparison with in situ measurements at Mars' surface

Aromatic organic salts such as benzoates or phthalates may be widespread degradation products of organic molecules at the surface of Mars. The low volatility of these aromatic carboxylic salts could have compromised their detection through thermal extraction in situ analyses such as those performed by the Viking landers. However, over the years, analytical chemistry laboratories on board current and future Martian surface missions, such as the Sample Analysis at Mars (SAM) instrument suite on board the Curiosity rover and the Mars Organic Molecule Analyzer (MOMA) instrument of the Rosalind Franklin ExoMars rover, respectively, have evolved. These instruments have improved in efficiency to detect refractory and polar organic compounds, which could influence the detection of aromatic organic salts. To evaluate the capability of detecting aromatic organic salts on Mars with in situ instruments, we performed laboratory experiments under Viking, SAM, and MOMA-like Gas Chromatography-Mass Spectrometry (GC–MS) conditions with two carboxylic acid/salt couples: phthalic acid/calcium phthalate and benzoic acid/calcium benzoate. We studied the behavior and signatures of both molecular forms when using pyrolysis and derivatization experiments and the implications of these results in the search for organic molecules on Mars. This study showed that the Viking experiments could not have detected the presence of aromatic carboxylic salts in Martian samples because its maximum pyrolysis temperature was too low (500 °C). However, we showed that calcium benzoate and calcium phthalate, despite their refractory nature, could be identified indirectly through the detection of thermal and derivatized degradation products, both with SAM and MOMA. No conclusive proof of the presence of these aromatic organic salt species have been found in the SAM in situ data but given the right instrumental set-up they could be detected if present. The conclusions of this work raise essential questions on the detectability of refractory molecules, the analytical efficiency of flight instruments, and the interpretation of in situ data.

Ethnobotanical investigation of medicinal and aromatic plants used in the traditional treatment of COVID-19 in the rural commune of Bni Hadifa, province of Al Hoceima (Central Rif, Northern Morocco)

This ethnobotanical investigation was conducted in the rural commune of Bni Hadifa belonging to the Al Hoceima province (North of Morocco), to inventory the principal medicinal plants traditionally used to treat Covid-19. Ethnobotanical information was recorded from 84 inhabitants aged over 18 years in the different communes of the study area, using an ethnobotanical survey based on a questionnaire and semistructured interviews. Data were examined by surveying the relative citation frequency (RFC) and family importance value (FIV). The obtained results permitted the inventory of 40 aromatic and medicinal plants (MAPs) species owned by 20 families, the most important of which by their number of species were: Lamiaceae (12 species), Apiaceae (5 species), Asteraceae (3 species), and two species for each of Amaryllidaceae, Myrtaceae, and Rutaceae. Furthermore, the following species: Allium sativum, Thymus glandulosus, Lavandula dentata L, Citrus limon L, Eucalyptus globulus labill, Artemisia herba-alba, and Marrubium vulgare L were the most frequently cited by the RFC index. Leaves were found to be the common plant organ used to treat Covid-19, while decoction was the most frequent preparation mode. This study also showed that over 90% of the respondents proved the efficacy of the plants used against Covid-19. However, most of the users of these plants did not respect the administered doses and were unaware of the toxicity and lethal effects that could be caused by these plants when taking high doses. The results of this survey demonstrate that the plants used to combat Covid-19 may constitute a promising database for future research in the extraction and chemical analysis of potentially effective biomolecules against this virus.

Carvacrol: A Prospective Gold Mine of New Drug Discovery and Development

Carvacrol, a widely extracted monoterpenoid phenol from an abundant number of aromatic plant species including thyme and oregano. At present, carvacrol is being utilized in low concentrations as a preservative and food flavoring agent, in addition to serving as a fragrance element in cosmetic formulations. A great deal of study has been done in recent years as an effort to determine the biological effects of carvacrol for possible therapeutic application. Carvacrol has been identified to have a vast range of biological and pharmacological characteristics which include antidiabetic, antimicrobial, antiinflammatory, anti-obesity, antitumor, hepatoprotective, gastroprotective, and neuroprotective effects based on both in vitro and in vivo experiments. The main objective of this review is to assess current understanding of carvacrol's pharmacological impacts as well as its biosynthesis and plant sources in order to potentially inform the future researchers. It can be postulated that upon extensive research, this noteworthy bioactive phytochemical can be a very promising source of next generation drug development. Bangladesh Pharmaceutical Journal 27(1): 116-125, 2024 (January)

The Antioxidant and Antibacterial Potential of Thyme and Clove Essential Oils for Meat Preservation—An Overview

Consumers are looking for safer and more natural food options that are produced through natural methods without using synthetic preservatives. They also desire extended shelf life for their food products. Several medicinal and aromatic plants species combine food, spice, aromatic, and medicinal recognized attributes. The essential oils from these plants contain a unique mixture of compounds specific to each plant, showing notable antioxidant and antimicrobial properties. Essential oils are used widely as they are environmentally friendly, non-toxic, and biodegradable substitutes for harsh chemical preservatives. Thyme and clove are aromatic plants commonly used in traditional gastronomy, particularly in meat-based recipes. The preservation effects of these essential oils on fresh meat have not been widely studied. Therefore, the aim of this study is to review the use of thyme and clove essential oils in meat preservation, with particular emphasis on their antioxidant properties to mitigate lipid and protein oxidation. Different strategies have been used to boost the effects of essential oils in foods, which include mixtures of essential oils, encapsulation and nanoemulsification techniques, with or without edible coatings. The final objective is to promote the wide use of essential oils for meat preservation, eventually in combination with other innovative approaches.

N-acetyl amino acid amide solubility in aqueous 1,6-hexanediol solutions: Insights into the protein droplet deformation mechanism

Proteinaceous liquid droplets, generated by liquid–liquid phase separation, function as membraneless compartments that are essential for diverse biological functions. Studies addressing droplet generation have used 1,6-hexanediol (1,6-HD) as a droplet-discerning agent owing to its capacity to induce droplet deformation. Despite the empirical utility of 1,6-HD, the mechanism underlying 1,6-HD-induced droplet deformation remains unknown. In this study, the solubilities of N-acetyl amino acid amides, which correspond to proteinogenic amino acid residues, were examined in the presence of 1,6-HD at 25 °C. Other solvents included ethanol, 1-propanol, and amides. Remarkably, 1,6-HD effectively solubilized hydrophobic species (particularly aromatic species) and exhibited reduced efficacy in solubilizing hydrophilic species and peptide bond moieties. These solubilizing effects are reflected in changes in protein solubility and structure. Specifically, 1,6-HD primarily targets the hydrophobic regions of a protein, increasing protein solubility without causing substantial structural changes. This solubilization mechanism is essential for elucidating the role of 1,6-HD as a droplet-discerning agent and recognizing its potential limitations.

Improving the propylene selectivity in the methanol-to-olefins reaction over CIT-17, a SAT-type molecular sieve

Small-pore, cage-containing molecular sieves exhibit high selectivities toward light olefins in the methanol-to-olefins (MTO) reaction. However, the ability to alter the olefins product selectivities while achieving high carbon efficiency remains a challenge for this complex reaction network. Here, the synthesis, characterization, and catalytic testing of several SAT-type molecular sieves: SAPO (CIT-17), MgAPO (STA-2), and CoAPO (STA-2) are reported. Several CHA- (e.g., SAPO-34, MgAPO-34, and CoAPO-34) and AEI-type (e.g., SAPO-18, MgAPO-18, and CoAPO-18) molecular sieves are synthesized and tested for comparisons. The SAT materials exhibit high propylene selectivities ranging from approximately 35 % to 50 % in the MTO reaction. Remarkably high propylene-to-ethylene ratios (P/E) ranging from 1.64 to 4.17 are achieved, depending on the reaction conditions and molecular sieve properties. These P/E ratios are higher than those obtained from CHA- (P/E = 0.91–1.31) and AEI-type (P/E = 2.10–2.34) materials at complete or near-complete methanol conversion. The enhanced P/E ratios exhibited by the SAT-type catalysts with low silicon contents (e.g., CIT-17 (Si/T-atom = 0.083)) are ascribed to the time-on-stream delay in the maturation of aromatic species that are comprised primarily of tri- and tetra-methylbenzenes. The results from this study demonstrate the subtle cooperativity between the narrow SAT cage (cage-defining ring (CDR) size of 6.6 Å) and low acidity of CIT-17. These factors together create a conducive microenvironment that facilitates the conversion of methanol-to-propylene by promoting the olefins cycle, particularly in early stages of the reaction, and reducing the contribution of the aromatics cycle.

External standard calibration method for high-repetition-rate shock tube kinetic studies with synchrotron-based time-of-flight mass spectrometry.

The signal levels observed from mass spectrometers coupled by molecular beam sampling to shock tubes are impacted by dynamic pressures in the spectrometer due to rapid pressure changes in the shock tube. Accounting for the impact of the pressure changes is essential if absolute concentrations of species are to be measured. Obtaining such a correction for spectrometers operated with vacuum ultra violet photoionization has been challenging. We present here a new external calibration method which uses VUV-photoionization of CO2 to develop time-dependent corrections to species concentration/time profiles from which kinetic data can be extracted. The experiments were performed with the ICARE-HRRST (high repetition rate shock tube) at the DESIRS beamline of synchrotron SOLEIL. The calibration experiments were performed at temperatures and pressures behind reflected shock waves of 1376 ± 12 K and 6.6 ± 0.1 bar, respectively. Pyrolytic experiments with two aromatic species, toluene (T5 = 1362 ± 22 K, P5 = 6.6 ± 0.2 bar) and ethylbenzene (T5 = 1327 ± 18 K, P5 = 6.7 ± 0.2 bar), are analyzed to test the method. Time dependent concentrations for molecular and radical species were corrected with the new method. The resulting signals were compared with chemical kinetic simulations using a recent mechanism for pyrolytic formation of polycyclic aromatic hydrocarbons. Excellent agreement was obtained between the experimental data and simulations, without adjustment of the model, demonstrating the validity of the external calibration method.

Potassium 2-germanaphthalenide: an isolable polycyclic system of germanium-incorporated anionic benzenoid

A germanium analogue of the 2-naphthyl anion, 2-germanaphthalenide, has been isolated. While it possesses ambident character as both aromatic and germylene species, the germylene character is further emphasized as compared with germabenzenide.

Formation of five-membered ring structures via reactions of o-benzyne

The formation of five-membered ring structures is important for the generation of curved and bowl-shaped polycyclic aromatic hydrocarbons (PAHs) under combustion conditions. Here, we report the identification of the indenyl (C9H7) radical – the simplest aromatic hydrocarbon radical carrying an adjacent five- and six-membered ring, as the major product of the o-benzyne (o-C6H4) reaction with propargyl (C3H3). Because real flames exhibit a complex chemistry, elucidation of a specific reaction is very challenging. Instead, we studied the o-C6H4 + C3H3 reaction in a resistively heated microtubular SiC reactor at controlled conditions of 1150 K and a pressure near 10–20 Torr. To this end, the reactants o-benzyne and propargyl were pyrolytically generated from benzoyl chloride and propargyl bromide. We identified the reactants and the indenyl radical isomer-selectively utilizing photoion mass-selected threshold photoelectron spectroscopy (ms-TPES). The experimentally observed predominant formation of indenyl radicals finally confirms the theoretical predictions of Matsugi and Miyoshi [Phys. Chem. Chem. Phys. 14 (2012), 9722–9728] and highlights a versatile route for the formation of five-membered rings and curved PAHs via reactions of o-benzyne that favor the formation of multiring species over aliphatically substituted aromatic species.

Ag(Sn9-Sn9)]5- and [(η4-Sn9)Ag(η1-Sn9)]7-, as aggregates of spherical aromatic building blocks. Persistence of aromaticity upon cluster gathering.

Formation of cluster-based materials requires a fundamental understanding of the resulting cluster aggregation processes. The Sn94- Zintl-ion structure can be viewed as a building block featuring a spherical aromatic species, leading to a cluster gathering upon oxidative coupling and/or mediated by transition metals. Here, we evaluate the spherical aromatic properties of [Sn9-Sn9]6-, [Ag(Sn9-Sn9)]5- and [(η4-Sn9)Ag(η1-Sn9)]7-, as aggregates of two Sn9 building units held together via oxidative coupling and mediated by a Ag(I) transition metal center. Our results from magnetic criteria of aromaticity show that the inherent spherical aromatic characteristics of the parent Sn94- cluster are persistent in the overall aggregate where the enabled shielding cones ascribed to each Sn9 unit are able to interplay between them, leading to an overlap of the shielding regions. Hence, the two approaches for bringing cluster units together are able to retain the inherent spherical aromatic features for each Sn9 unit, leading to a cluster-based dimer where the parent properties remain. Thus, further cluster-based materials can be envisaged from aggregation upon oxidative coupling and/or mediated by transition metals, where the constituent building blocks retain their initial features, useful to guide the formation of more complex cluster-based aggregates.

A Study on the Germination of Origanum acutidens L. Seeds Subjected to Pre-Treatment of Gibberellic Acid and Colchicine

In Türkiye, the general name for aromatic plant species belonging to the Lamiaceae family is “thyme”. However, species containing thymol/carvacrol type essential oil are considered “thyme”. Origanum acutidens is one of the thyme species that grows endemic in the Northeastern Anatolia Region of Türkiye. The low germination rate of its seeds is one of the factors limiting the studies conducted on this plant. This study was conducted to investigate the effects of different doses of colchicine and gibberellic acid on germination in O. acutident seeds. Seeds collected from the plant’s natural habitat at the end of the flowering period were used as plant material. The experiment was planned as control (only distilled water) and treatments consisting of three different gibberellic acid (GA3) [100 ppm (GA1), 200 ppm (GA2) and 300 ppm (GA3)] and four different colchicine doses [0.01 mM (C1), 0.02 mM (C2), 0.04 mM (C3) and 0.08 mM (C4)]. The applications were kept at 25±1 ⁰C for 12 hours. After the waiting period, all seeds were filtered and placed, 50 seeds each, in 9 cm diameter petri dishes between two layers of sterile filter paper sheets. The experiment was carried out in 4 replications. Some parameters of the germination (Germination rate (GR), Germination time (GT), Average germination time (AGT)) and early seedling period (Embryonal root length (ERL), Number of embryonal roots (NER), Root fresh weight (RFW), Root dry weight (RDW), Grass sheath length (GSH)) were measured and the results were statistically evaluated. In general, the highest values obtained from all evaluated germination (92.0% GR and 1.7 day AGT) and early seedling parameters (10.4 cm ERL, 4.6 NER, 0.095 g RFW, 0.028 g RDW and 3.6 cm GSL) were found to belong to the GA3 application. The lowest values obtained from the relevant parameters were obtained with the C4 application. In our study, it was observed that gibberellic acid applications significantly increased germination in this plant and positively increased the parameters related to germination. Based on the study results, we think that colchicine stimulates germination at certain rates, but causes death by having a toxic effect in increasing doses.

Investigation of the Effect of Main Components of Wild Thyme on Covid-19 by Computational Methods

Aromatic plant species of the genus thymus have an important role as they have therapeutic properties such as antirheumatic, antiseptic, antispasmodic, antimicrobial, cardiac, carminative, diuretic and expectorant. It is also known that such plants strengthen the immune system and help cope with infectious diseases such as colds and flu. In this study, the effects of thymol, p-cymene, -terpinene, bornyl acetate, borneol, carvacrol, thymol methyl ether, thymol acetate, which are the main components of wild thyme (thymus serpyllum L.), on Covid-19 were investigated at the molecular level. Optimizations and molecular docking were done in Docking Server with the MMFF94 method. Major components of wild thyme were docked separately against 6LU7 protein representing the first gene form of Covid-19 and 7KDL protein representing the mutated form. Docking poses and binding energies between target proteins and wild thyme components were calculated. The results were compared with favipiravir, an antiviral drug developed against influenza virus and also used in the treatment of Covid-19. It was found that the thymol molecule, one of the main components of wild thyme, has the highest biological activity against both 6LU7 and 7KDL protein chains of Covid-19.

Carbones - A Classification on the Magnetic Criterion.

Carbones (carbodiphosphoranes, bent allenes and chalcogen-stabilized carbones) bear the same resonance contributor X+ -C2- -Y+ (X+ , Y+ =PR3 + , CR2 + , SR2 + , SeR2 + , S+ R2 =NR) and exhibit unique bonding and donating properties at the central carbon atom. A classification is given on basis of both the geometry and the magnetic properties (13 C chemical shift of the central carbon atom and the spatial magnetic properties, through-space NMR shieldings (TS NMRSs), actually the anisotropy effect or the ring current effect of aromatic species). TS NMRS values have been calculated using the GIAO perturbation method employing the nucleus independent chemical shift (NICS) concept and the results visualized as iso-chemical-shielding surfaces (ICSS) of various size and direction. The synergy of geometry (linear or bent, orthogonal or twisted structures) and NMR characteristics (extend of the high field shift of the central carbon atom, anisotropy effect of the allene-like C=C double bonds or the ball-like anisotropy effect of carbone-like central carbon atom) provides a comprehensive picture of the dominating resonance contributor.

Reliable Information about Electrochemical Potentials from Cyclic Voltammograms That Look “Messy”

The importance of voltammetry for characterizing electronic properties of molecular species and (nano)materials cannot be overstated. Among the most broadly used electroanalytical techniques, cyclic voltammetry (CV) offers an incomparably facile means for estimating standard electrochemical potentials, E (0), which are essential for analysis of charge transfer, energy conversion and photocatalysis [Phys. Chem. Chem. Phys. 2020, 22, 21583-21629]. Redox irreversibility, liquid-junction potentials, and uncertainties about the microenvironment on the surfaces of polarized working electrodes present key challenges for the validity of CV analysis [Curr. Opin. Electrochem. 2022, 31, 100862]. As an average of anodic and cathodic peak potentials extracted from cyclic voltammograms, half-wave potentials, E (1/2), serve as a good approximation for E (0). This approximation is acceptable for results from voltammograms exhibiting even partial chemical reversibility [J. Electrochem. Soc. 2019, 166, H3175-H3187]. Conversely, cyclic voltammograms lacking an anodic or cathodic peak die to irreversible reduction or oxidation, respectively, render estimating E (1/2) impossible. In fact, irreversibility of electrochemical oxidation and reduction is more or less the rule rather than the exception. Statistical analysis of a series of voltammograms allows us to demonstrate that the potentials at the inflection points at the rise of the cathodic and anodic waves represent a good approximation of E (1/2) for reduction and oxidation, respectively [J. Electrochem. Soc. 2019, 166, H3175-H3187]. The use of inflection potentials significantly broadens the applicability of CV for extracting meaningful results from voltammograms showing irreversible behavior. It allows us to investigate in parallel a series of electron-rich and electron-deficient polycyclic aromatic species not only with similar structures, but also with similar spin-density distributions of their radical ions, regardless their stability and reversible redox behavior in different solution media. Reformulating the Rehm-Weller equation for CT thermodynamic analysis, offers a means for eliminating the effects of liquid-junction potentials while studying electron donor-acceptor pairs [Proc. Natl. Acad. Sci. USA 2021, 118, e2026462118]. Employing this approach to donors and acceptors with similar structures reveals patterns correlated with the microenvironment at the surfaces of polarized working electrodes. Global-fit analysis of the dependence of CV-extracted reduction potentials on the concentration of the supporting electrolyte for different solvents yields information about the liquid-junction potentials in the electrochemical cell and about the polarity of the microenvironment of the redox species at the electrode surface [J. Phys. Chem. B 2023, 127, 1443-1458]. These outcomes offer a key foundation not only for improved voltammetric estimates of standard electrochemical potentials of redox species, but also for the polarity dependence of these potentials, permitting their broad applicability to systems in widely different media.

Sustainable approach for the collection and processing of medicinal and aromatic plants in Hungary

AbstractHungary is a Central European country that is rich in medicinal and aromatic wild plant species; in rural livelihoods, the collection, use, process, and trade of these plants are traditionally important contributors. However, due to several recent changes touching the sector, the natural ecosystems, biodiversity, and collectors - who generally belong to poorer social groups – are affected negatively.The paper aims to introduce the Hungarian herbal sector from a holistic perspective, including its economic, environmental, and human dimensions, with a particular focus on sustainability. In this context, the purpose of the article is to discover this field as comprehensibly as possible and present it from both theoretical and practical aspects. Another objective is to collect the best practices and feasible solutions from the field in connection with promoting a harmonious, as well as economically prosperous relationship between nature and local people. This integrated approach helps show the industry's strengths and advantages, as well as its weaknesses and challenges. Based on the findings, the paper attempts also to propose some recommendations for the future.

An ethnobotanical study of aromatic medicinal plants of Swat Valley, Pakistan

Abstract. Ali S, Munazir M, Sher H, Qureshi R, Akram M. 2023. An ethnobotanical study of aromatic medicinal plants of Swat Valley, Pakistan. Asian J Ethnobiol 6: 163-172. Plants play a key role in local medicines and are a source of income, as in the case of Swat, Pakistan, which is rich in medicinal plants coupled with rich in the practice of traditional knowledge and diverse cultures. So, the present study aimed to record the cultural uses of aromatic medicinal plants commonly used as medicines by herbalists from remote areas in Swat Valley. The survey was carried out in 2021 and 2023 using a semi-structured questionnaire with a total of 106 people were interviewed. A total of 33 aromatic medicinal plant species belonging to 30 genera and 14 families were identified and recorded. Lamiaceae was the most commonly used plant family (33%), followed by Apiaceae (18%), Rutaceae (9%), Zingiberaceae (6%), and Myrtaceae (6%). Herbs were commonly used for herbal recipes with 23 species (69%), followed by shrubs (12%), trees (15%), and climbers (3%). Shoots and leaves (30%) were the most commonly used parts of the plants, followed by fruits (18%), seeds (15%), bulbs (6%), rhizomes, bark, and needles (3%). In terms of mode of application, powder was the most common mode (42%), followed by dried (30%), infusions (27%), decoctions (24%), crushing (6%), and heating (3%). The highest Relative Frequency of Citation (RFC) was Skimmia laureola with 0.84, while Anisomeles indica had the lowest RFC (0.13). In terms of Fidelity Level (FL), Zingiber officinale had the highest FL (83%), while Sium latifolium had the lowest FL (13%). The recorded aromatic medicinal plants are mostly used to treat stomach problems. It has also been observed that elderly people are more knowledgeable than younger ones. Therefore, the present study suggests that these plants should be screened for new compounds linked to their reported use in the development of new therapeutics.

High-efficient co-removal of copper and zinc by modified biochar derived from tea stalk: Characteristics, adsorption behaviors, and mechanisms

Tieguanyin tea stem was used as a raw material, and potassium hydroxide (KOH), hydrochloric acid (HCl), potassium ferrate (K2FeO4), and other modifiers were used to synthesize three modified biochar (HCl-BC, KOH-BC, Fe-BCs), for competitive adsorption of copper (Cu2+) and zinc (Zn2+). Among them, Fe-BCs had the highest adsorption capacity. Fe-BC650 (K2FeO4-modified biochar heated at 650 °C) could reach adsorption equilibrium in 1 min with a high adsorption capacity. The maximum adsorption capacity of Fe-BC650 for Cu (II) and Zn (II) in the single-heavy metal solution was 303.5996 mg/g and 254.0711 mg/g, respectively. However, there were antagonistic impacts between Cu2+ and Zn2+ after analysis by the extended Langmuir model. The Brunauer-Emmett-Teller (BET) results indicated the specific surface area of Fe-BC650 was multiplied by 245 than the raw biochar (BC650), and the iron species was present in the pores of biochar through FeO bonding rather than on the surface. The results of dissolved organic carbon showed that iron species promoted the formation of aromatic structure but decreased the abundance of aromatic species in the composition. Moreover, K2FeO4 provided a large amount of K+ that could undergo cation exchange reactions with Cu2+ and Zn2+. The heavy metals became flocculent precipitate(MCO3) and deposited at the bottom of the centrifuge tube by flocculation. These characteristics constitute the excellent adsorption performance of Fe-BC650.

Understanding of gas-phase methane pyrolysis towards hydrogen and solid carbon with detailed kinetic simulations and experiments

Methane (CH4) pyrolysis is studied in a tubular flow reactor for the production of hydrogen and solid carbon by combining kinetic modelling, numerical simulation and experiments in a high-temperature flow reactor. Operating conditions are varied such as temperature in the range of 1273–1873 K, hydrogen addition to the feed with a molar H2:CH4 ratio between 0 and 4, and residence time in the range of 3–7 s. Elementary-step reaction mechanisms consisting of pyrolysis and carbon coupling reactions among C1, C2, aromatic and polycyclic aromatic hydrocarbon species are used in the numerical simulations of the species profiles in flow direction. A thermodynamic analysis is performed to acquire the boundary conditions for operation as well to estimate probable by-products (C2H2, C2H4, C2H6, C6H6, C16H10 etc.) over the temperature range. Gas-phase kinetic modelling is performed revealing that CH4 conversion starts at temperatures above 1273 K. Higher temperatures increase CH4 conversion and H2 yield peaking at 1573 K. The cooling temperature gradient downstream of the hot zone in the reactor causes reverse reactions in gas-phase suppressing CH4 conversion. H2 addition to the feed is found to be a crucial parameter for controlling the by-product formation. In the experimental study, a solid carbon yield of 84 % is achieved while gaseous by-products remain less than 1 mol-% at 1673 K, H2:CH4 ratio of 2, and residence time of 5 s. Gas-phase reactions are found to be coupled to surface reactions at higher temperatures.