New Tricks for Old Guys: Recent Developments in the Chemistry, Biochemistry, Applications and Exploitation of Selected Species from the Lamiaceae Family

Bioactive Compounds from Medicinal Plants as Potential Adjuvants in the Treatment of Mild Acne Vulgaris

In recent years, there has been a growing interest in the use of medicinal plants and phytochemicals as potential treatments for acne vulgaris. This condition, characterized by chronic inflammation, predominantly affects adolescents and young adults. Conventional treatment typically targets the key factors contributing to its development: the proliferation of Cutibacterium acnes and the associated inflammation. However, these treatments often involve the use of potent drugs. As a result, the exploration of herbal medicine as a complementary approach has emerged as a promising strategy. By harnessing the therapeutic properties of medicinal plants and phytochemicals, it may be possible to address acne vulgaris while minimizing the reliance on strong drugs. This approach not only offers potential benefits for individuals seeking alternative treatments but also underscores the importance of natural remedies of plant origin in dermatological care. The primary aim of this study was to assess the antimicrobial, antioxidant, and anti-inflammatory properties of plants and their phytochemical constituents in the management of mild acne vulgaris. A comprehensive search of scientific databases was conducted from 2018 to September 2023. The findings of this review suggest that medicinal plants and their phytochemical components hold promise as treatments for mild acne vulgaris. However, it is crucial to note that further research employing high-quality evidence and standardized methodologies is essential to substantiate their efficacy and safety profiles.

Implications of the Propagation Method for the Phytochemistry of Nepeta cataria L. throughout a Growing Season

Catnip (Nepeta cataria L.) plants produce a wide array of specialized metabolites with multiple applications for human health. The productivity of such metabolites, including nepetalactones, and natural insect repellents is influenced by the conditions under which the plants are cultivated. In this study, we assessed how field-grown catnip plants, transplanted after being propagated via either single-node stem cuttings or seeds, varied regarding their phytochemical composition throughout a growing season in two distinct environmental conditions (Pittstown and Upper Deerfield) in the state of New Jersey, United States. Iridoid terpenes were quantified in plant tissues via ultra-high-performance liquid chromatography with triple quadrupole mass spectrometry (UHPLC-QqQ-MS), and phenolic compounds (phenolic acids and flavonoids) were analyzed via UHPLC with diode-array detection (UHPLC-DAD). The highest contents of total nepetalactones in Pittstown were found at 6 weeks after transplanting (WAT) for both seedlings and cuttings (1305.4 and 1223.3 mg/100 g, respectively), while in Upper Deerfield, the highest contents for both propagules were at 11 WAT (1247.7 and 997.1 mg/100 g, respectively) for seed-propagated and stem cuttings). The highest concentration of nepetalactones was associated with floral-bud to partial-flowering stages. Because plants in Pittstown accumulated considerably more biomass than plants grown in Upper Deerfield, the difference in nepetalactone production per plant was striking, with peak productivity reaching only 598.9 mg per plant in Upper Deerfield and 1833.1 mg per plant in Pittstown. Phenolic acids accumulated in higher contents towards the end of the season in both locations, after a period of low precipitation, and flavone glycosides had similar accumulation patterns to nepetalactones. In both locations, rooted stem cuttings reached their maximum nepetalactone productivity, on average, four weeks later than seed-propagated plants, suggesting that seedlings have, overall, better agronomic performance.

Investigation of Volatile Components and Assessment of Antioxidant Potential in Seven Lamiaceae Plant Hydrosols

Aromatic plants of the family Lamiaceae, especially of the genus Thymus, have promising antioxidant applications in pharmacology, medicine, food, cosmetology, and aromatherapy. Hydrosols (HDs) were extracted by hydrodistillation from seven species of Lamiaceae, including Thymus vulgaris, Thymus mongolicus, Mentha × piperita, Melissa officinalis, Rosmarinus officinali, Salvia elegans, and Leonurus artemisia. In total, 369 volatile components were determined and analyzed by gas chromatography-mass spectrometry (GC-MS). Among them, alcohols (2.86-28.48%), ethers (2.46-10.69%), and phenols (0.11-21.78%) constituted a large proportion, mainly linalool (0.28-19.27%), eucalyptol (0.16-6.97%), thymol (0-19.54%), and carvacrol (0-26.82%). Multivariate statistical analyses were performed and 27 differential metabolites were screened. Three different methods (ABTS+•, DPPH•, and FRAP) were used to determine the in vitro antioxidant activity of seven HDs. Thymus vulgaris hydrosols (Tv HDs) and Thymus mongolicus hydrosols (Tm HDs) had the strongest antioxidant activity and their stronger antioxidant capacity was related to their high levels of phenolic constituents, mainly thymol. The antioxidant activity of the other five Lamiaceae HDs was associated with their high alcohol (mainly linalool and eucalyptol) content, and the alcohol constituents may synergistically affect their antioxidant capacity. Therefore, the present study suggests that Lamiaceae plants can be utilized as antioxidant products or antioxidants in different industrial sectors including pharmaceuticals, food, cosmetics, and agrochemicals.

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

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

The Potential of Lamiaceae Herbs for Mitigation of Overweight, Obesity, and Fatty Liver: Studies and Perspectives

Numerous plants, plant extracts, and plant-derived compounds are being explored for their beneficial effects against overweight and liver diseases. Obesity is associated with the increased prevalence of non-alcoholic fatty liver disease (NAFLD), becoming the most common liver disease in Western countries. Obesity and NAFLD are closely associated with many other metabolic alternations such as insulin resistance, diabetes mellitus, and cardiovascular diseases. Many herbs of the Lamiaceae family are widely employed as food and spices in the Mediterranean area, but also in folk medicine, and their use for the management of metabolic disorders is well documented. Hereby, we summarized the scientific results of the medicinal and nutraceutical potential of plants from the Lamiaceae family for prevention and mitigation of overweight and fatty liver. The evidence indicates that Lamiaceae plants may be a cost-effective source of nutraceuticals and/or phytochemicals to be used in the management of metabolic-related conditions such as obesity and NAFLD. PubMed, Google Scholar, Scopus, and SciFinder were accessed to collect data on traditional medicinal plants, compounds derived from plants, their reported anti-obesity mechanisms, and therapeutic targets.

Foliar micromorphology of selected medicinal Lamiaceae taxa and their taxonomic implication using scanning electron microscopy

In this research, 25 medicinally used Lamiaceae species belonging to 20 genera have been studied and identified for the nine disorders. We used scanning electron microscopy (SEM) for qualitative and quantitative morphological character identification. The micromorphological characters observed here were important for distinguishing the studied taxa. The highest medicinal values were reported for Vitex negundo and Scutellaria baicalensis for all considered categories except urinary and otorhinolaryngology disorders. The foliar epidermal anatomical characteristics revealed that the micromorphological features of the Lamiaceae species provide taxonomically significant and accurate identification information to delimitate the family species. Moreover, we focused on both qualitative (epidermal cell shape, stomata type, stomatal pore shape, subsidiary cell shape, glandular trichomes, and non-glandular trichome shape) as well as quantitative features (epidermal cell size, stomata size, stomatal pore size, subsidiary cell size, and trichomes size). The trichomes diversity was different in most species' on adaxial and abaxial surfaces. In most species, anomocytic stomata were observed, but other types such as diacytic, paracytic, and tetracytic type stomata were also examined. The diverse pattern of anatomical characters suggests that the studied taxa provide insight evidence for the taxonomic observation of the Traditional Chinese Medicinal plants from the Lamiaceae. This work sets an avenue for future research and taxonomic exploration of medicinal flora through microscopic investigations.

Ethnobotanical Survey on Bitter Tea in Taiwan

Ethnopharmacological evidence: In Taiwan, herbal tea is considered a traditional medicine and has been consumed for hundreds of years. In contrast to regular tea, herbal teas are prepared using plants other than the regular tea plant, Camellia sinensis (L.) Kuntze. Bitter tea (kǔ-chá), a series of herbal teas prepared in response to common diseases in Taiwan, is often made from local Taiwanese plants. However, the raw materials and formulations have been kept secret and verbally passed down by store owners across generations without a fixed recipe, and the constituent plant materials have not been disclosed.

Aim of the study: The aim was to determine the herbal composition of bitter tea sold in Taiwan, which can facilitate further studies on pharmacological applications and conserve cultural resources.

Materials and methods: Interviews were conducted through a semi-structured questionnaire. The surveyed respondents were traditional sellers of traditional herbal tea. The relevant literature was collated for a systematic analysis of the composition, characteristics, and traditional and modern applications of the plant materials used in bitter tea. We also conducted an association analysis of the composition of Taiwanese bitter tea with green herb tea (qing-cao-cha tea), another commonly consumed herbal tea in Taiwan, as well as herbal teas in neighboring areas outside Taiwan.

Results: After visiting a total of 59 stores, we identified 32 bitter tea formulations and 73 plant materials. Asteraceae was the most commonly used family, and most stores used whole plants. According to a network analysis of nine plant materials used in high frequency as drug pairs, Tithonia diversifolia and Ajuga nipponensis were found to be the core plant materials used in Taiwanese bitter tea.

Conclusion: Plant materials used in Taiwanese bitter tea were distinct, with multiple therapeutic functions. Further research is required to clarify their efficacy and mechanisms.

Origanum vulgare ssp. hirtum (Lamiaceae) Essential Oil Prevents Behavioral and Oxidative Stress Changes in the Scopolamine Zebrafish Model

Origanum vulgare ssp. hirtum has been used as medicinal herbs promoting antioxidant, anti-inflammatory, antimicrobial, and neuroprotective activities. We investigated the protective effects and the mechanism of O. vulgare ssp. hirtum essential oil (OEO) on cognitive impairment and brain oxidative stress in a scopolamine (Sco)-induced zebrafish (Danio rerio) model of cognitive impairment. Our results show that exposure to Sco (100 µM) leads to anxiety, spatial memory, and response to novelty dysfunctions, whereas the administration of OEO (25, 150, and 300 µL/L, once daily for 13 days) reduced anxiety-like behavior and improved cognitive ability, which was confirmed by behavioral tests, such as the novel tank-diving test (NTT), Y-maze test, and novel object recognition test (NOR) in zebrafish. Additionally, Sco-induced brain oxidative stress and increasing of acetylcholinesterase (AChE) activity were attenuated by the administration of OEO. The gas chromatography-mass spectrometry (GC-MS) analyses were used to elucidate the OEO composition, comprising thymol (38.82%), p-cymene (20.28%), and γ-terpinene (19.58%) as the main identified components. These findings suggest the ability of OEO to revert the Sco-induced cognitive deficits by restoring the cholinergic system activity and brain antioxidant status. Thus, OEO could be used as perspective sources of bioactive compounds, displaying valuable biological activities, with potential pharmaceutical applications.

Simultaneous Hydrodistillation-Steam Distillation of Rosmarinus officinalis, Lavandula angustifolia and Citrus aurantium from Morocco, Major Terpenes: Impact on Biological Activities

Interest in the use of essential oils (EOs) in the biomedical and food industries have seen growing over the last decades due to their richness in bioactive compounds. The challenges in developing an EO extraction process that assure an efficient levels of monoterpenes with impact on biological activities have driven the present study, in which the EO extraction process of rosemary, lavender and citrus was performed by simultaneous hydrodistillation-steam distillation, and the influence of EO composition on biological activities, namely antioxidant, anti-inflammatory, antidiabetic, anti-acetylcholinesterase, anti-tyrosinase, antibacterial, and antibiofilm activity, were evaluated. The EO yields of combinations were generally higher than the individual plants (R. officinalis (Ro), L. angustifolia (La), and C. aurantium (Ca)) extracted by the conventional hydrodistillation. The EOs obtained by this process generally had a better capacity for scavenging the free radicals, inhibiting α-glucosidase, and acetylcholinesterase activities than the individual EOs. The combination of EOs did not improve the ability for scavenging peroxide hydrogen or the capacity for inhibiting lipoxygenase activity. The antioxidant activity or the enzyme inhibition activity could not only be attributed to their major compounds because they presented lower activities than the EOs. The chemical composition of the combination Ro:La:Ca, at the ratio 1/6:1/6:2/3, was enriched in 1,8-cineole, linalool, and linalyl acetate and resulted in lower MIC values for all tested strains in comparison with the ratio 1/6:2/3:1/6 that was deprived on those components. The biofilm formation of Gram positive and Gram negative bacteria was impaired by the combination Ro:La:Ca at a sub-inhibitory concentration.

Oregano and Thyme Essential Oils Encapsulated in Chitosan Nanoparticles as Effective Antimicrobial Agents against Foodborne Pathogens

The use of natural compounds with biocidal activity to fight the growth of bacteria responsible for foodborne illness is one of the main research challenges in the food sector. This study reports the preparation and physicochemical characterization of chitosan nanoparticles loaded with Thymus capitatus (Th-CNPs) and Origanum vulgare (Or-CNPs) essential oils. The nanosystems were obtained by ionotropic gelation technique with high encapsulation efficiency (80-83%) and loading capacity (26-27%). Nanoparticles showed a spherical shape, bimodal particle size distribution, and good stability (zeta potential values > 40 mV). The treatment of the nanosuspensions at different temperatures (4 and 40 °C) and storage times (7, 15, 21, and 30 days) did not affect their physicochemical parameters and highlights their reservoir ability for essential oils also under stressful conditions. Both Or-CNPs and Th-CNPs exhibited an enhanced bactericidal activity against foodborne pathogens (S. aureus, E. coli, L. monocytogenes) than pure essential oils. These ecofriendly nanosystems could represent a valid alternative to synthetic preservatives and be of interest for health and food safety.

Phytogenic Bioactive Compounds Shape Fish Mucosal Immunity

Aquaculture growth will unavoidably involve the implementation of innovative and sustainable production strategies, being functional feeds among the most promising ones. A wide spectrum of phytogenics, particularly those containing terpenes and organosulfur compounds, are increasingly studied in aquafeeds, due to their growth promoting, antimicrobial, immunostimulant, antioxidant, anti-inflammatory and sedative properties. This trend relies on the importance of the mucosal barrier in the fish defense. Establishing the phytogenics' mode of action in mucosal tissues is of importance for further use and safe administration. Although the impact of phytogenics upon fish mucosal immunity has been extensively approached, most of the studies fail in addressing the mechanisms underlying their pharmacological effects. Unstandardized testing as an extended practice also questions the reproducibility and safety of such studies, limiting the use of phytogenics at commercial scale. The information presented herein provides insight on the fish mucosal immune responses to phytogenics, suggesting their mode of action, and ultimately encouraging the practice of reliable and reproducible research for novel feed additives for aquafeeds. For proper screening, characterization and optimization of their mode of action, we encourage the evaluation of purified compounds using in vitro systems before moving forward to in vivo trials. The formulation of additives with combinations of compounds previously characterized is recommended to avoid bacterial resistance. To improve the delivery of phytogenics and overcome limitations associated to compounds volatility and susceptibility to degradation, the use of encapsulation is advisable. Besides, newer approaches and dedicated methodologies are needed to elucidate the phytogenics pharmacokinetics and mode of action in depth.

Comprehensive Phenolic and Free Amino Acid Analysis of Rosemary Infusions: Influence on the Antioxidant Potential

The phenolics profile, free amino acids composition, and antioxidant potential of rosemary infusions were studied. Forty-four compounds belonging to nine different groups (hydroxybenzoic acids, hydroxycinnamic acids, flavan-3-ols, flavanones, flavones, phenolic diterpenes, hydroxybenzaldehydes, coumarins, and pyranochromanones) were identified by UHPLC-ESI-Q-TOF-MS. Of these, seven were firstly described in rosemary infusions: a rosmanol derivative, two dihydroxycoumarin hexosides, a hydroxybenzaldehyde, a dihydroxybenzoic acid hexoside, coumaric acid hexoside, and isocalolongic acid. The free amino acid profile of the beverages was also reported by the first time with seven amino acids found (asparagine, threonine, alanine, tyrosine, phenylalanine, isoleucine, and proline). Furthermore, DPPH^• scavenging ability, Ferric Reducing Antioxidant Power and Oxygen Radical Absorbance Capacity, as well as total phenolics and flavonoids contents, were assessed. Overall, rosemary infusions showed to be a very good source of antioxidants. A 200 mL cup of this infusion contributes to the ingestion of ~30 mg of phenolic compounds and about 0.5–1.1 μg of free amino acids. This type of beverages may present a positive impact on the maintenance of the body antioxidant status and contribute to the prevention of oxidative stress related diseases.

Bioactivity of Different Chemotypes of Oregano Essential Oil against the Blowfly Calliphora vomitoria Vector of Foodborne Pathogens

Simple Summary

Calliphora vomitoria L. is a very common synanthropic blowfly. Since it is attracted by human food, it plays a main role in the transmission of foodborne diseases. Among aromatic plant essential oils (EOs), those of spices are the most suitable to protect food from insect pests. In the present work, we determined the bioactivity of three oregano EOs against C. vomitoria. The chemical analyses showed that the EOs belonged to three chemotypes, one with a prevalence of carvacrol and two with a prevalence of thymol. The bioassays showed that the bioactivity of the EOs significantly varies among chemotypes, with the thymol chemotype showing an overall higher efficacy compared to the carvacrol one.

Abstract

Blowflies play a substantial role as vectors of microorganisms, including human pathogens. The control of these insect pests is an important aspect of the prevention of foodborne diseases, which represent a significant public health threat worldwide. Among aromatic plants, spices essential oils (EOs) are the most suitable to protect food from insect pests. In this study, we determined the chemical composition of three oregano EOs and assessed their toxicity and deterrence to oviposition against the blowfly Calliphora vomitoria L. The chemical analyses showed that the EOs belonged to three chemotypes: one with a prevalence of carvacrol, the carvacrol chemotype (CC; carvacrol, 81.5%), and two with a prevalence of thymol, the thymol/p-cymene and thymol/γ-terpinene chemotypes (TCC and TTC; thymol, 43.8, and 36.7%, respectively). The bioassays showed that although all the three EOs chemotypes are able to exert a toxic activity against C. vomitoria adults (LD₅₀ from 0.14 to 0.31 μL insect⁻¹) and eggs (LC₅₀ from 0.008 to 0.038 μL cm⁻²) as well as deter the oviposition (Oviposition Activity Index, OAI, from 0.40 ± 0.04 to 0.87 ± 0.02), the bioactivity of oregano EOs significantly varies among the chemotypes, with the thymol-rich EOs (TCC and TTC) overall demonstrating more effectiveness than the carvacrol-rich (CC) EO.

Nanoencapsulated Essential Oils with Enhanced Antifungal Activity for Potential Application on Agri-Food, Material and Environmental Fields

Nanotechnology is a new frontier of this century that finds applications in various fields of science with important effects on our life and on the environment. Nanoencapsulation of bioactive compounds is a promising topic of nanotechnology. The excessive use of synthetic compounds with antifungal activity has led to the selection of resistant fungal species. In this context, the use of plant essential oils (EOs) with antifungal activity encapsulated in ecofriendly nanosystems could be a new and winning strategy to overcome the problem. We prepared nanoencapsules containing the essential oils of Origanum vulgare (OV) and Thymus capitatus (TC) by the nanoprecipitation method. The colloidal suspensions were characterized for size, polydispersity index (PDI), zeta potential, efficiency of encapsulation (EE) and loading capacity (LC). Finally, the essential oil nanosuspensions were assayed against a panel of fourteen fungal strains belonging to the Ascomycota and Basidiomycota phyla. Our results show that the nanosystems containing thyme and oregano essential oils were active against various fungal strains from natural environments and materials. In particular, the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values were two to four times lower than the pure essential oils. The aqueous, ecofriendly essential oil nanosuspensions with broad-spectrum antifungal activity could be a valid alternative to synthetic products, finding interesting applications in the agri-food and environmental fields.

Thymus vulgaris Essential Oil Protects Zebrafish against Cognitive Dysfunction by Regulating Cholinergic and Antioxidants Systems

Thymus vulgaris L. is an aromatic herb used for medicinal purposes such as antimicrobial, spasmolytic, antioxidant, anti-inflammatory, antinociceptive, antitumor, and may have beneficial effects in the treatment of Alzheimer’s disease. The present study aimed to investigate whether Thymus vulgaris L. essential oil enhances cognitive function via the action on cholinergic neurons using scopolamine (Sco)-induced zebrafish (Danio rerio) model of memory impairments. Thymus vulgaris L. essential oil (TEO, 25, 150, and 300 µL/L) was administered by immersion to zebrafish once daily for 13 days, whereas memory impairment was induced by Sco (100 μM), a muscarinic receptor antagonist, delivered 30 min before behavioral tests. Spatial memory was assessed using the Y-maze test and novel object recognition test (NOR). Anxiety and depression were measured in the novel tank diving test (NTT). Gas Chromatograph-Mass Spectrometry (GC-MS) analysis was used to study the phytochemical composition of TEO. Acetylcholinesterase (AChE) activity and oxidative stress response in the brain of zebrafish were determined. TEO ameliorated Sco-induced increasing of AChE activity, amnesia, anxiety, and reduced the brain antioxidant capacity. These results suggest that TEO may have preventive and/or therapeutic potentials in the management of memory deficits and brain oxidative stress in zebrafish with amnesia.

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

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

Balkans' Asteraceae Species as a Source of Biologically Active Compounds for the Pharmaceutical and Food Industry

Herbal drugs are a useful source of different bioactive compounds. Asteraceae species, as the most widespread vascular plants, can be used both as food and as medicine due to the great diversity of recorded chemical components - different phenolic compounds, terpenes, carotenoids, vitamins, alkaloids, etc. The Balkan Peninsula is characterized by great diversity of plants from Asteraceae family, including presence of rare and endemic species. In this review, results of the survey of chemical composition and biological activity, mainly focusing on antioxidant, antimicrobial and anticancer effects of selected Balkans' Asteraceae species were provided. In addition, information on edible plants from Asteraceae family is presented, due to growing interest for the so-called 'healthy diet' and possible application of Balkans' Asteraceae species as food of high nutritional value or as a source of functional food ingredients.