Production and Diversity of Volatile Terpenes from Plants on Calcareous and Siliceous Soils: Effect of Soil Nutrients

The Entourage Effect in Cannabis Medicinal Products: A Comprehensive Review

This study explores the complementary or synergistic effects of medicinal cannabis constituents, particularly terpenes, concerning their therapeutic potential, known as the entourage effect. A systematic review of the literature on cannabis "entourage effects" was conducted using the PRISMA model. Two research questions directed the review: (1) What are the physiological effects of terpenes and terpenoids found in cannabis? (2) What are the proven "entourage effects" of terpenes in cannabis? The initial approach involved an exploratory search in electronic databases using predefined keywords and Boolean phrases across PubMed/MEDLINE, Web of Science, and EBSCO databases using Medical Subject Headings (MeSH). Analysis of published studies shows no evidence of neuroprotective or anti-aggregatory effects of α-pinene and β-pinene against β-amyloid-mediated toxicity; however, modest lipid peroxidation inhibition by α-pinene, β pinene, and terpinolene may contribute to the multifaceted neuroprotection properties of these C. sativa L. prevalent monoterpenes and the triterpene friedelin. Myrcene demonstrated anti-inflammatory proprieties topically; however, in combination with CBD, it did not show significant additional differences. Exploratory evidence suggests various therapeutic benefits of terpenes, such as myrcene for relaxation; linalool as a sleep aid and to relieve exhaustion and mental stress; D-limonene as an analgesic; caryophyllene for cold tolerance and analgesia; valencene for cartilage protection; borneol for antinociceptive and anticonvulsant potential; and eucalyptol for muscle pain. While exploratory research suggests terpenes as influencers in the therapeutic benefits of cannabinoids, the potential for synergistic or additive enhancement of cannabinoid efficacy by terpenes remains unproven. Further clinical trials are needed to confirm any terpenes "entourage effects."

A Transcriptomic and Metabolomic Study on the Biosynthesis of Iridoids in Phlomoides rotata from the Qinghai-Tibet Plateau

Phlomoides rotata is a traditional Chinese herbal medicine that grows in the Qinghai-Tibet Plateau region at a 3100-5000 m altitude. Iridoid compounds are the main active compounds of the P. rotata used as medical ingredients and display anti-inflammatory, analgesic, and hepatoprotective properties. To better understand the biological mechanisms of iridoid compounds in this species, we performed a comprehensive analysis of the transcriptome and metabolome of P. rotata leaves from four different regions (3540-4270 m). Global metabolome profiling detected 575 metabolites, and 455 differentially accumulated metabolites (DAMs) were detected in P. rotata leaves from the four regions. Eight major DAMs related to iridoid metabolism in P. rotata leaves were investigated: shanzhiside methyl ester, 8-epideoxyloganic acid, barlerin, shanzhiside, geniposide, agnuside, feretoside, and catalpin. In addition, five soil physical and chemical indicators in P. rotata rhizosphere soils were analyzed. Four significant positive correlations were observed between alkaline nitrogen and geniposide, exchangeable calcium and geniposide, available potassium and shanzhiside, and available phosphorus and shanzhiside methyl ester. The transcriptome data showed 12 P. rotata cDNA libraries with 74.46 Gb of clean data, which formed 29,833 unigenes. Moreover, 78.91% of the unigenes were annotated using the eight public databases. Forty-one candidate genes representing 23 enzymes involved in the biosynthesis of iridoid compounds were identified in P. rotata leaves. Moreover, the DXS1, IDI1, 8-HGO1, and G10H2 genes associated with iridoid biosynthesis were specifically expressed in P. rotata. The integration of transcriptome and metabolome analyses highlights the crucial role of soil physical and chemical indicators and major gene expression related to iridoid metabolism pathways in P. rotata from different areas. Our findings provide a theoretical foundation for exploring the molecular mechanisms underlying iridoid compound accumulation in P. rotata.

Evaluating Potential Anxiolytic Effects of Minor Cannabinoids and Terpenes After Acute and Chronic Oral Administration in Rats

Background: Cannabis and its primary psychoactive constituent delta-9-tetrahydrocannabinol (D9-THC) produce biphasic, dose-dependent effects on anxiety. In addition to D9-THC, cannabis contains other "minor" cannabinoids and terpenes with purported therapeutic potential for the treatment of anxiety. Empirical data on potential therapeutic effects of these compounds is limited. The current study evaluated the effects of selected minor cannabinoids and terpenes in a battery of tests sensitive to anxiolytic and anxiogenic drugs. Methods: In Experiment 1, adult male Sprague Dawley rats (N=7-8/group) were administered acute oral doses of one of five minor cannabinoids: delta-8-tetrahydrocannabinol (D8-THC; 10 mg/kg), tetrahydrocannabivarin (32 mg/kg), cannabidiolic acid (32 mg/kg), cannabidivarin (32 mg/kg), and cannabigerol (100 mg/kg), or one of five terpenes: D-limonene (17 mg/kg), ⍺-pinene (100 mg/kg), ⍺-terpineol (10 mg/kg), bisabolol (100 mg/kg), and β-caryophyllene (17 mg/kg), or vehicle (medium-chain triglycerides [MCT] oil). Ethyl alcohol was tested as an active comparator. Thirty minutes post-administration, the marble burying test, the three-chamber social interaction test, and the novelty-induced hypophagia test were completed; motor activity was assessed throughout testing. Experiment 2 examined the potential anxiolytic effects of minor cannabinoids when administered chronically; rats administered MCT oil or minor cannabinoids in Experiment 1 continued receiving once-daily doses for 21 days and were assessed using the same test battery after 7, 14, and 21 days of administration. Results and Conclusions: When compared to vehicle, acute administration of bisabolol and D-limonene increased the amount of food consumed and bisabolol-, D-limonene-, ⍺-pinene-, and β-caryophyllene decreased percent time spent in the outer zone in the novelty-induced hypophagia test, suggestive of an anxiolytic effect. Only ethanol increased social interaction. After acute administration, anxiogenic effects in the marble burying test were observed for D8-THC, but not for other minor cannabinoids and terpenes. Throughout chronic administration, only D8-THC displayed anxiogenic effects in the novelty-induced hypophagia test. The other cannabinoids did not show anxiolytic or anxiogenic effects in any of the tests at the doses or times tested. The minor cannabinoids and terpenes did not impair or stimulate general motor activity. These data provide a foundation for future studies investigating cannabinoid/terpene interactions.

Cistus albidus L.-Review of a Traditional Mediterranean Medicinal Plant with Pharmacological Potential

Cistus albidus L. (Cistaceae) is a medicinal plant that has been used therapeutically since ancient times in the Mediterranean basin for its important pharmacological properties. The ability of C. albidus to produce large quantities of a wide range of natural metabolites makes it an attractive source of raw material. The main constituents with bioactive functions that exert pharmacological effects are terpenes and polyphenols, with more than 200 identified compounds. The purpose of this review is to offer a detailed account of the botanical, ethnological, phytochemical, and pharmacological characteristics of C. albidus with the aim of encouraging additional pharmaceutical investigations into the potential therapeutic benefits of this medicinal plant. This review was carried out using organized searches of the available literature up to July 2023. A detailed analysis of C. albidus confirms its traditional use as a medicinal plant. The outcome of several studies suggests a deeper involvement of certain polyphenols and terpenes in multiple mechanisms such as inflammation and pain, with a potential application focus on neurodegenerative diseases and disorders. Other diseases such as prostate cancer and leukemia have already been researched with promising results for this plant, for which no intoxication has been reported in humans.

Use of Multivariate Analysis to Unravel the Differences between Two Chamomile Varieties and Their Anticancer and Antioxidant Activities

BACKGROUND

Plants from the Asteraceae family were commonly used to treat various diseases. The metabolomic profile of this family consisted of bioactive flavonoids and other phenolics. Chamomile is a member of the Asteraceae family. Jordanian and European chamomile are two varieties of Matricaria chamomilla (German chamomile), which were grown under different environmental conditions, were studied. Many examples of plant varieties with significant distinction in the secondary metabolite they afford have been described in the literature. Multivariate statistical analysis was employed to measure the depth of this variation in two chamomile varieties.

METHODS

From both types, crude extracts were prepared using solvents of different polarities and tested for their biological activity. The semipolar fraction of the European variety showed anticancer and antioxidant activity. Meanwhile, the semipolar fraction of the Jordanian type exhibited only antioxidant activity. Both extracts were fractionated, and then the biological activity was again assayed.

RESULTS

European and Jordanian chamomile fractions produced dicaffeoylquinic acid isomers exhibiting antioxidant capability. Additionally, Z-glucoferulic acid was produced from the European chamomile, demonstrating antioxidant activity. The European samples afforded two major compounds, chrysosplenetin and apigenin, that displayed anticancer activity.

CONCLUSIONS

Different environmental conditions between Jordanian and European chamomile affected the type of isolated compounds. Structure elucidation was performed with HPLC-MS coupled with dereplication techniques and 2D NMR experiments.

Rosemary and neem methanolic extract: antioxidant, cytotoxic, and larvicidal activities supported by chemical composition and molecular docking simulations

This study aimed to employ GC-MS to assess the chemical composition of MeOH leaf extracts of R. officinalis and A. indica and evaluate their insecticidal, antioxidant, and antibacterial activities. Twelve components, representing 98.61% and 100% of the total volatile compounds, were deduced from the extracted R. officinalis and A. indica, respectively, using this method. In R. officinalis extract, limonene is typically positioned as the main component (23.03%), while the main chemicals identified in A. indica extract were methyl (E)-octadec-13-enoate (23.20%) and (2R)-1,3,8-trimethyl-4-propyl-5-ethyl-2-(1-hydroxyethyl)-7-methoxycardonylethyl-6-methylenecarbonyl-porphyrin (23.03%). Both extracts of R. officinalis and A. indica exhibited different toxicity against the stored grain pest T. castaneum, with LC₅₀ values of 1.470 and 2.588 mg/ml, respectively. Additionally, after 4 and 5 h of treatment at a concentration of 0.2 mg/ml, the A. indica extract showed the highest levels of repellent action (81.4% and 93.4%), and the R. officinalis extract showed a good repellent rate (64.9% and 80.7%) against T. castenum larvae. With an IC₅₀ value of 35.83 and 28.68 mg/L and a radical scavenging activity percentage of 67.76% and 72.35%, the leaf extract was found to be the most potent plant extract when tested for DPPH antioxidant activity. Overall results showed that MeOH extracts of R. officinalis and A. indica were more effective against S. aureus than E. coli. To determine how the investigated chemicals attach to the active sites of E. coli DNA gyrase A and S. aureus undecaprenyl diphosphate synthase, docking studies were carried out. The consensus score analysis showed that limonene exhibits the best binding energy with both enzymes in docking analysis and more stability in molecular dynamics simulations. The RMSD was obtained at 20.6 and 4.199 (Kcal/mole). The two compounds were successfully used in molecular dynamics simulation research to generate stable complexes with DNA gyrase A.

Trade-Off between Facilitation and Interference of Allelopathic Compounds in Vegetation Recovery: The Case of Rosmarinus officinalis in Degraded Gypsum Habitats

Rosmarinus officinalis advantageously competes with other species in restored gypsum outcrops, and further research is needed to understand the causes. Specifically, we focus on the potential allelopathic effects derived from its terpenes on the emergence of gypsum species. To this end, we established 120 circular subplots in a previously restored gypsum outcrop, and randomly applied four different treatments based on the presence/absence of rosemary plants and their leaves on the soil. Afterwards, we conducted an experimental sowing of native gypsophiles. All subplots were monitored to estimate seedling emergence, and soil and leaf samples were analysed for terpenes. The results show that the treatments had significant effects on the overall emergence of seedlings, and terpenes were found in rosemary leaves and soils, with no significant differences in terpene composition. In particular, we identified a clear negative effect in the treatment where rosemary plants were eliminated but its leaves were left along with allelopathy (2.57 ± 0.54 individuals/subplot). Unexpectedly, the presence of rosemary plants seems to facilitate the emergence of gypsum species (9.93 ± 1.61 individuals/subplot), counteracting the effects of the allelopathic substances in the soil. Consequently, we do not suggest removing rosemary plants in early stages to encourage the emergence of gypsum species in restored areas.

Medical food development by dietetic management of the endocannabinoid system through dietary sources of β-caryophyllene

Objective: To research the biological impact on the endocannabinoid system (ECS) from dietary sources of [Formula: see text]-caryophyllene (BCP). This will encompass pre-clinical and clinical research for BCP. The bioavailability of BCP will be explored, focusing on bioavailability improvement. This research will establish if there is justification to warrant the development of a medical food for supporting the ECS through dietetic supplementation of BCP.

Methods: Research and review papers were identified through the search engines Google Scholar, PubMed, and ScienceDirect. Main keywords included [Formula: see text]-caryophyllene, endocannabinoid system, dietary cannabinoids, cannabinoid type-2 receptor, and bioavailability.

Results: The human body is limited in the digestion of BCP from food. This is because BCP is poorly absorbed in the gut. Everyone has different underlying endocannabinoid efficiency and most people do not have the full potential of supporting their ECS through diet.

Conclusion: A medical food can be developed to use BCP with a delivery system, so that the bioactive food cannabinoid is readily absorbed. This will deliver dietary support to the ECS, that otherwise would be available from food.

This review provides insight into the efficacy of using BCP in medical foods as dietary support for the ECS. Supporting the ECS can assist in maintaining homeostasis, regulating immune function, pain intensity, inflammatory markers, sleep patterns, mood, appetite, and stress susceptibility.

Nocturnal pollination: an overlooked ecosystem service vulnerable to environmental change

Existing assessments of the ecosystem service of pollination have been largely restricted to diurnal insects, with a particular focus on generalist foragers such as wild and honey bees. As knowledge of how these plant-pollinator systems function, their relevance to food security and biodiversity, and the fragility of these mutually beneficial interactions increases, attention is diverting to other, less well-studied pollinator groups. One such group are those that forage at night. In this review, we document evidence that nocturnal species are providers of pollination services (including pollination of economically valuable and culturally important crops, as well as wild plants of conservation concern), but highlight how little is known about the scale of such services. We discuss the primary mechanisms involved in night-time communication between plants and insect pollen-vectors, including floral scent, visual cues (and associated specialized visual systems), and thermogenic sensitivity (associated with thermogenic flowers). We highlight that these mechanisms are vulnerable to direct and indirect disruption by a range of anthropogenic drivers of environmental change, including air and soil pollution, artificial light at night, and climate change. Lastly, we highlight a number of directions for future research that will be important if nocturnal pollination services are to be fully understood and ultimately conserved.

Infestation of Field Dodder (Cuscuta campestris Yunck.) Promotes Changes in Host Dry Weight and Essential Oil Production in Two Aromatic Plants, Peppermint and Chamomile

Peppermint (Mentha piperita L.) and chamomile (Chamomilla recutita (L.) Rausch.) are aromatic plants with considerable economic value. These plants and their essential oils are used in medicine, cosmetics, and the food industry. One of the main limiting factors in peppermint and chamomile commercial cultivation is weed competition since weeds are able to decrease both oil amount and biomass yield. The purpose of the present study was to determine the effect of parasitism by field dodder (Cuscuta campestris Yunck.) on peppermint and chamomile dry weight and their essential oil yield and composition. Essential oils from both noninfested and infested peppermint and chamomile plants were obtained by hydrodistillation and characterized chemically by gas chromatography (GC) coupled with mass spectrometry (MS). The amount of dry matter accumulated by peppermint and chamomile plants infested by field dodder was lower (25% and 63%, respectively) compared to noninfested plants. Essential oil yield increased for peppermint (3.87% (v/w) and 3.63% (v/w)), but decreased for chamomile (0.2% (v/w) and 0.5% (v/w)) both from infested and noninfested plants, respectively. The oil composition profile significantly differed in terms of content. In peppermint plants, field dodder infestation increased menthone content by 23%, and decreased the content of both menthol by 11% and pulegone by 67%. Furthermore, δ-cadinene was detected only in oil extracted from infested peppermint plants. Compared to peppermint, chamomile plants were significantly more affected by field dodder in terms of essential oil yield, as well as oil composition and plant dry weight. In chamomile plants, (E)-dendrolasin was detected in the oil of noninfested plants, and 1,4-dimethyl-7-(1-methylethyl)-azulen-2-ol was detected only in the oil of infested plants.

Metabolomics Approaches for Analyzing Effects of Geographic and Environmental Factors on the Variation of Root Essential Oils of Ferula assa-foetida L

Environmental factors shape the production and accumulation processes of plant secondary metabolites in medical and aromatic plants and thus their pharmacological and biological activity. Using an environmental metabolomics approach, we determined chemotypes and specific compounds on the basis of essential oils (EOs) from roots of 10 Iranian Ferula assa-foetida L. populations and related them to geographical, climate, and edaphic data. GC-MS revealed three distinct chemotypes characterized by (I) monoterpenes and Z-1-propenyl sec-butyl disulfide; (II) eudesmane sesquiterpenoids and α-agarofuran; and (III) Z- and E-1-propenyl sec-butyl disulfide. NIRS measurements indicated a similar but less distinct pattern. Structural equation models showed that EO constituents and content were directly influenced by edaphic factors (texture, pH, and iron, potassium, and aluminum content) and temperature and predominantly indirectly by latitude, longitude, and altitude. Predicting EO constituents or chemotypes by geographical, climate, and soil factors can be used in F. assa-foetida to select populations with specific EO characteristics.

Electrophysiological Responses of the Beech Leaf-Mining Weevil, Orchestes fagi, to Seasonally-Variant Volatile Organic Compounds Emitted by American Beech, Fagus grandifolia

The beech leaf-mining weevil, Orchestes fagi, is a common pest of European beech, Fagus sylvatica, and has recently become established in Nova Scotia, Canada where it similarly infests American beech, F. grandifolia. We collected volatile organic compounds (VOCs) emitted by F. grandifolia leaves at five developmental stages over one growing season and simultaneously analyzed them for volatile emissions and O. fagi antennal response using gas chromatography-electroantennographic detection (GC-EAD). Volatile profiles changed significantly throughout the growing season, shifting from primarily β-caryophyllene, methyl jasmonate, and simple monoterpene emissions to dominance of the bicyclic monoterpene sabinene during maturity. Two VOCs dominant during bud burst, (R)-(+)-limonene and geranyl-p-cymene, may be of biological relevance due to the highly specific oviposition period of O. fagi at this stage though antennal responses were inconclusive. Senescence showed a decrease in blend complexity with an increase in (Z)-3-hexenyl acetate and (Z)-3-hexen-1-ol as well as a resurgence of α-terpinene and geranyl-p-cymene. We present a novel electroantennal preparation for O. fagi. Antennae of both male and female O. fagi responded to the majority of detectable peaks for host volatiles presented via GC-EAD. Females displayed greater overall sensitivities and less specificity to host volatiles and it is hypothesized that this translates to more generalist olfaction than males. It is clear that olfactory cues are important physiologically though their implications on behaviour are still unknown. The results presented in this study provide a baseline and tools on which to connect the complex and highly time-specific phenology of both F. grandifolia and the destructive pest O. fagi through which olfactory-based lures can be investigated for monitoring systems.

Effects of Soil Fertilization on Terpenoids and Other Carbon-Based Secondary Metabolites in Rosmarinus officinalis Plants: A Comparative Study

Rosmarinus officinalis is an evergreen aromatic plant with important commercial interest as it contains numerous essential oils (composed of terpenoid compounds) and phenolic constituents (natural antioxidant compounds). This work aims at evaluating the concomitant effects of different inorganic and organic fertilization treatments and the subsequent increases in soil nutrient availability on terpenoids and other carbon-based secondary metabolites, e.g., flavonoids and phenolic compounds, in Rosmarinus officinalis leaves. The results showed that, as expected, the structural carbohydrate content (lignocellulosic compounds) in stems was higher in fertilized plants than in controls. Additionally, positive correlations were observed of the absolute amounts of total terpenoids and some single terpenoid compounds with N or P contents in leaves. On the contrary, the phenolic and flavonoid concentrations in all the rosemary plant parts were lower with the fertilization treatments. Indeed, negative correlations between the phenolic compounds (and flavonoids) and N in rosemary leaves were also found. Overall, the results suggest that the terpenoid production's response to fertilization was due to N, which is essential for protein synthesis and terpene synthase activity, and to P, which is necessary for the synthesis of both terpenoid precursors and ATP and NADPH, also needed for terpenoid synthesis. On the other hand, the basis for the fertilization's effects on the production of phenolic compounds is the direct nitrogen trade-off between growth and the shikimic acid pathway by which phenolics compounds are synthesized.

The Essential Oil of Salvia rosmarinus Spenn. from Italy as a Source of Health-Promoting Compounds: Chemical Profile and Antioxidant and Cholinesterase Inhibitory Activity

The chemical composition of the essential oil from Salvia rosmarinus Spenn. collected in Calabrian Ionian (R1) and Tyrrhenian (R2) coast (Southern Italy) was examined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Essential oils are mainly characterized by monoterpene hydrocarbons (39.32-40.70%) and oxygenated monoterpenes (36.08-39.47%). The 1,8-cineole, α-pinene, camphor, and trans-caryophyllene are the most representative compounds. S. rosmarinus essential oils were investigated for their antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing ability power (FRAP), and β-carotene bleaching tests. Additionally, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity assays were used to screen the neuroprotective effects of S. rosmarinus. R2 showed the highest antioxidant potential as confirmed by relative antioxidant capacity index (RACI) and exhibited a selective activity against AChE (half maximal inhibitory concentration, IC50, value of 41.86 μg/mL). These results suggest S. rosmarinus essential oil as a potential source of bioactive compounds.

Effect of β-caryophyllene from Cloves Extract on Helicobacter pylori Eradication in Mouse Model

New antibacterial treatments against Helicobacter pylori are needed as H. pylori is acquiring antibiotic resistance. β-caryophyllene is a natural bicyclic sesquiterpene, with anti-inflammatory and antimicrobial effects. This study investigates the effects of H-002119-00-001 from β-caryophyllene on the eradication of H. pylori in a mouse model, and its effects on the inflammation of the gastric mucosa. To evaluate the anti-H.pylori efficacy of β-caryophyllene, a total of 160 mice were divided into eight groups (n = 10 each) and were administered different treatments for 2 and 4 weeks. H. pylori eradication was assessed using a Campylobacter-like organism (CLO) test and H. pylori qPCR of the gastric mucosa. The levels of inflammation of gastric mucosa were assessed using histology and immunostaining. H-002119-00-001 decreased bacterial burden in vitro. When H-002119-00-001 was administered to mice once daily for 2 weeks, cure rates shown by the CLO test were 40.0%, 60.0%, and 70.0% in groups 6, 7, and 8, respectively. H. pylori levels in gastric mucosa decreased dose-dependently after H-002119-00-001 treatment. H-002119-00-001 also reduced levels of inflammation in gastric mucosa. H-002119-00-001 improved inflammation and decreased bacterial burden in H. pylori-infected mouse models. H-002119-00-001 is a promising and effective therapeutic agent for the treatment of H. pylori infection.

Variation of Secondary Metabolite Profile of Zataria multiflora Boiss. Populations Linked to Geographic, Climatic, and Edaphic Factors

Geographic location and connected environmental and edaphic factors like temperature, rainfall, soil type, and composition influence the presence and the total content of specific plant compounds as well as the presence of a certain chemotype. This study evaluated whether geographic, edaphic, and climatic information can be utilized to predict the presence of specific compounds from medicinal or aromatic plants. Furthermore, we tested rapid analytical methods based on near infrared spectroscopy (NIR) coupled with gas chromatography/flame ionization (GC/FID) and gas chromatography/mass spectrometry (GC/MS) analytical methods for characterization and classification metabolite profiling of Zataria multiflora Boiss. populations. Z. multiflora is an aromatic, perennial plant with interesting pharmacological and biological properties. It is widely dispersed in Iran as well as in Pakistan and Afghanistan. Here, we studied the effect of environmental factors on essential oil (EO) content and the composition and distribution of chemotypes. Our results indicate that this species grows predominantly in areas rich in calcium, iron, potassium, and aluminum, with mean rainfall of 40.46 to 302.72 mm·year^-1 and mean annual temperature of 14.90°C to 28.80°C. EO content ranged from 2.75% to 5.89%. Carvacrol (10.56-73.31%), thymol (3.51-48.12%), linalool (0.90-55.38%), and p-cymene (1.66-13.96%) were the major constituents, which classified 14 populations into three chemotypes. Corresponding to the phytochemical cluster analysis, the hierarchical cluster analysis (HCA) based on NIR data also recognized the carvacrol, thymol, and linalool chemotypes. Hence, NIR has the potential to be applied as a useful tool to determine rapidly the chemotypes of Z. multiflora and similar herbs. EO and EO constituent content correlated with different geographic location, climate, and edaphic factors. The structural equation models (SEMs) approach revealed direct effects of soil factors (texture, phosphor, pH) and mostly indirect effects of latitude and altitude directly affecting, e.g., soil factors. Our approach of identifying environmental predictors for EO content, chemotype or presence of high amounts of specific compounds can help to select regions for sampling plant material with the desired chemical profile for direct use or for breeding.

Recent advances in allelopathy for weed control: from knowledge to applications

Allelopathy is the biological phenomenon of chemical interactions between living organisms in the ecosystem, and must be taken into account in addressing pest and weed problems in future sustainable agriculture. Allelopathy is a multidisciplinary science, but in some cases, aspects of its chemistry are overlooked, despite the need for a deep knowledge of the chemical structural characteristics of allelochemicals to facilitate the design of new herbicides. This review is focused on the most important advances in allelopathy, paying particular attention to the design and development of phenolic compounds, terpenoids and alkaloids as herbicides. The isolation of allelochemicals is mainly addressed, but other aspects such as the analysis and activities of derivatives or analogs are also covered. Furthermore, the use of allelopathy in the fight against parasitic plants is included. The past 12 years have been a prolific period for publications on allelopathy. This critical review discusses future research areas in this field and the state of the art is analyzed from the chemist's perspective. © 2019 Society of Chemical Industry.

Efficacy of a Combination of N-Palmitoylethanolamide, Beta-Caryophyllene, Carnosic Acid, and Myrrh Extract on Chronic Neuropathic Pain: A Preclinical Study

Neuropathic pain (NP) is a common public health problem that poses a major challenge to basic scientists and health-care providers. NP is a complex problem with an unclear etiology and an often-inadequate response to current medications. Despite the high number of drugs available, their limited pharmacological efficacy and side effects hamper their chronic use. Thus, the search for novel treatments is a priority. In addition to pharmaceuticals, natural extracts and food supplements are often used to help treating patients with NP. One such supplement is Noxiall^®, a commercially available combination of N-Palmitoylethanolamide (PEA), beta-caryophyllene; carnosic acid and myrrh. Here, we compare the efficacy of Noxiall^® to that of the medications gabapentin and pregabalin in the NP model of chronic constriction injury (CCI) using sciatic nerve ligation in mouse. Following CCI, mice developed a significant increase in mechanical allodynia and thermal hyperalgesia. Results showed that administration of either Noxiall^®, pregabalin, or gabapentin significantly attenuated mechanical allodynia. The magnitude of the Noxiall^® effect was comparable to that of gabapentin or pregabalin. In addition, co-administration of non-effective doses of pregabalin and Noxiall^® resulted in a significant decrease in NP, suggesting an additive efficacy. Noxiall^® was efficacious also in reducing CCI-induced thermal hyperalgesia. These findings support the rationale of using natural remedies in conjunction with classical pharmacological agents to treat chronic NP.

The sesquiterpene beta-caryophyllene oxide attenuates ethanol drinking and place conditioning in mice

Approximately 20 million adults in the United States have an alcohol use disorder. In recent years, modulation of the behavioral effects of ethanol by phytochemicals has been explored. In this study, we used the ethanol-induced loss of righting reflex (LORR) assay to assess potency differences between the sesquiterpene phytochemical beta-caryophyllene (BCP) and its derivative caryophyllene oxide (BCPO). We also investigated the effects of BCPO on two bottle-choice ethanol drinking and the ethanol-induced conditioned place preference (CPP). We then determined whether there are any pharmacokinetic or pharmacodynamic interactions between BCPO and ethanol, using blood ethanol analysis and pretreatments with the selective cannabinoid receptor 2 (CB2) antagonist AM630, respectively. BCPO augmented the ethanol-induced LORR at a dose (30 mg/kg) tenfold lower than BCP (300 mg/kg). Swiss-Webster mice were found to split into stable high and low drinking groups. This same dose (30 mg/kg) of BCPO significantly decreased ethanol intake and preference for ethanol over water in mice that consumed high amounts of ethanol, without any effect on total fluid intake. BCPO had limited effects in mice that consumed low amounts of ethanol. BCPO also significantly attenuated the ethanol-induced CPP. Blood ethanol analysis showed no significant effect of ethanol on the pharmacokinetics of ethanol. Furthermore, the enhancement of the ethanol-induced LORR by BCPO was reversed by AM630. These findings demonstrate that BCPO more potently modulates the behavioral effects of ethanol than the parent compound BCP. Moreover, they suggest that BCPO modulates the behavioral effects of ethanol through pharmacodynamic rather than pharmacokinetic mechanisms.

Chemical Profile and Biological Activities of Essential Oil from Artemisia vulgaris L. Cultivated in Brazil

Essential oil from the leaves of Artemisia vulgaris L. (Compositae) cultivated in Brazil was investigated for its chemical composition and biological activities including antibacterial, antifungal, and anthelmintic. The constituents of essential oils isolated by hydro-distillation were examined by GC-MS and a total of 18 components were identified. The essential oil was dominated by oxygenated sesquiterpenes (44.4%), sesquiterpene hydrocarbons (33.3%), and oxygenated monoterpenes (16.6%). Caryophyllene (37.45%), germacrene D (16.17%), and humulene (13.66%) were the major components. The essential oils from A. vulgaris showed bactericidal and fungicidal properties against Staphylococcus aureus and Candida albicans, respectively. Anthelmintic activity against Haemonchus contortus was absent in this essential oil. Altogether above results indicate that essential oils from A. vulgaris can be used for various medicinal purposes.

The combination of catechin, baicalin and β-caryophyllene potentially suppresses the production of inflammatory cytokines in mouse macrophages in vitro

It has been demonstrated that the combination of three botanical factors of (+)-catechin, baicalin and β-caryophyllene, which exhibit anti-inflammatory effects, with comparatively lower concentrations of each factor, demonstrating a potent synergistic-suppressive effect on the growth of mouse macrophage RAW264.7 cells in vitro, and suggesting it may function as a pharmacologic tool for managing inflammatory diseases. The present study was undertaken to determine the suppressive effects of (+)-catechin, baicalin or β-caryophyllene on the production of inflammatory cytokines, including TNF-α, IL-6 and IL-1β, which was enhanced by lipopolysaccharide (LPS) in RAW264.7 cells in vitro. The cells were cultured for 3 days without botanical factors, followed by incubation for 5 h in the presence of either vehicle, (+)-catechin [1 µg/ml (3.45 µM)], baicalin [1 µg/ml (2.24 µM)], or β-caryophyllene [1 µg/ml (5 µM)] with or without LPS (100 ng/ml); this did not have significant effects on the number of RAW264.7 cells. The production of TNF-α, IL-6 and IL-1β was not altered by the addition of (+)-catechin, baicalin, β-caryophyllene, or the three combined factors in RAW264.7 cells without LPS. LPS treatment caused a marked production of TNF-α, IL-6, and IL-1β. This enhancement was suppressed by the addition of (+)-catechin, baicalin or β-caryophyllene. Of note, the production of these cytokines was additively suppressed by the combination of the three factors in macrophages. Thus, the combination of (+)-catechin, baicalin and β-caryophyllene was found to reveal a potent suppressive effect on cytokine production in macrophages in vitro. This composition may be a useful tool as a potent anti-inflammatory agent.

Inhibitory effects of β-caryophyllene on Streptococcus mutans biofilm

OBJECTIVE

The biofilm of Streptococcus mutans is associated with induction of dental caries. Also, they produce glucan as an extracellular polysaccharide through glucosyltransferases and help the formation of cariogenic biofilm. β-caryophyllene has been used for therapeutic agent in traditional medicine and has antimicrobial activity. The purpose of this study was to investigate the effect of β-caryophyllene on S. mutans biofilm and the expression of biofilm-related factor.

DESIGN

The susceptibility assay of S. mutans for β-caryophyllene was performed to investigate inhibitory concentration for S. mutans growth. To evaluated the effect of β-caryophyllene on S. mutans biofilm, β-caryophyllene was treated on S. mutans in the various concentrations before or after the biofilm formation. Live S. mutans in the biofilm was counted by inoculating on Mitis-salivarius agar plate, and S. mutans biofilm was analyzed by confocal laser scanning microscope after staining bacterial live/dead staining kit. Finally, the expression of glucosyltransferases of S. mutans was investigated by real-time RT-PCR after treating with β-caryophyllene at the non-killing concentration of S. mutans.

RESULTS

The growth of S. mutans was inhibited by β-caryophyllene in above concentration of 0.078%, S. mutans biofilm was inhibited by β-caryophyllene in above 0.32%. Also, 2.5% of β-caryophyllene showed anti-biofilm activity for S. mutans biofilm. β-caryophyllene reduced the expression of gtf genes at a non-killing concentration for S. mutans. On the basis on these results, β-caryophyllene may have anti-biofilm activity and the inhibitory effect on biofilm related factor.

CONCLUSIONS

β-caryophyllene may inhibit cariogenic biofilm and may be a candidate agent for prevention of dental caries.

VOC emissions and carbon balance of two bioenergy plantations in response to nitrogen fertilization: A comparison of Miscanthus and Salix

Energy crops are an important renewable source for energy production in future. To ensure high yields of crops, N fertilization is a common practice. However, knowledge on environmental impacts of bioenergy plantations, particularly in systems involving trees, and the effects of N fertilization is scarce. We studied the emission of volatile organic compounds (VOC), which negatively affect the environment by contributing to tropospheric ozone and aerosols formation, from Miscanthus and willow plantations. Particularly, we aimed at quantifying the effect of N fertilization on VOC emission. For this purpose, we determined plant traits, photosynthetic gas exchange and VOC emission rates of the two systems as affected by N fertilization (0 and 80 kg ha^-1 yr^-1). Additionally, we used a modelling approach to simulate (i) the annual VOC emission rates as well as (ii) the OH^. reactivity resulting from individual VOC emitted. Total VOC emissions from Salix was 1.5- and 2.5-fold higher compared to Miscanthus in non-fertilized and fertilized plantations, respectively. Isoprene was the dominating VOC in Salix (80-130 μg g^-1 DW h^-1), whereas it was negligible in Miscanthus. We identified twenty-eight VOC compounds, which were released by Miscanthus with the green leaf volatile hexanal as well as dimethyl benzene, dihydrofuranone, phenol, and decanal as the dominant volatiles. The pattern of VOC released from this species clearly differed to the pattern emitted by Salix. OH^. reactivity from VOC released by Salix was ca. 8-times higher than that of Miscanthus. N fertilization enhanced stand level VOC emissions, mainly by promoting the leaf area index and only marginally by enhancing the basal emission capacity of leaves. Considering the higher productivity of fertilized Miscanthus compared to Salix together with the considerably lower OH^. reactivity per weight unit of biomass produced, qualified the C₄-perennial grass Miscanthus as a superior source of future bioenergy production.

Habitat-related variation in composition of the essential oil of Seseli rigidum Waldst. & Kit. (Apiaceae)

Plant specialised metabolites like essential oils are highly variable depending on genetic and various ecological factors. The aim of the present work was to characterise essential oils of the species Seseli rigidum Waldst. & Kit. (Apiaceae) in various organs on the individual and populational levels. Geographical variability and the impact of climate and soil type on essential oil composition were also investigated. Individually sampled essential oils of roots, aerial parts and fruits of plants from seven populations were analysed by GC-FID and GC-MS. The investigated populations showed high interpopulational and especially intrapopulational variability of essential oil composition. In regard to the variability of essential oils, different chemotypes were defined. The essential oils of S. rigidum roots represented a falcarinol chemotype, oils of aerial parts constituted an α-pinene or α-pinene/sabinene chemotype and fruit essential oils can be characterised as belonging to a complex sabinene/α-pinene/β-phellandrene/falcarinol/germacrene B chemotype. At the species level, analysis of variance (ANOVA), principal component analysis (PCA) and canonical discriminant analysis (CDA) showed that the plant part exerted the strongest influence on the composition of essential oils. Climate had a high impact on composition of the essential oils of roots, aerial parts and fruits, while influence of the substrate was less pronounced. The variations in main compounds of essential oils based on climate or substrate were complex and specific to the plant part.

β-Caryophyllene promotes osteoblastic mineralization, and suppresses osteoclastogenesis and adipogenesis in mouse bone marrow cultures in vitro

Osteoporosis is induced by the reduction in bone mass through decreased osteoblastic osteogenesis and increased osteoclastic bone resorption, and it is associated with obesity and diabetes. Osteoblasts and adipocytes are derived from bone marrow mesenchymal stem cells. The prevention of osteoporosis is an important public health concern in aging populations. β-caryophyllene, a component of various essential oils, is a selective agonist of the cannabinoid receptor type 2 and exerts cannabimimetic anti-inflammatory effects in animals. The present study aimed to identify the effect of β-caryophyllene on adipogenesis, osteoblastic mineralization and osteoclastogenesis in mouse bone marrow cell cultures in vitro. Bone marrow cells obtained from mouse femoral tissues were cultured in the presence of β-caryophyllene (0.1-100 µM) in vitro. The results revealed that β-caryophyllene stimulated osteoblastic mineralization, and suppressed adipogenesis and osteoclastogenesis. Thus, β-caryophyllene may be used as a therapeutic agent for the prevention and treatment of osteoporosis.

Mechanistic investigations on six bacterial terpene cyclases

The products obtained by incubation of farnesyl diphosphate (FPP) with six purified bacterial terpene cyclases were characterised by one- and two-dimensional NMR spectroscopic methods, allowing for a full structure elucidation. The absolute configurations of four terpenes were determined based on their optical rotary powers. Incubation experiments with ¹³C-labelled isotopomers of FPP in buffers containing water or deuterium oxide allowed for detailed insights into the cyclisation mechanisms of the bacterial terpene cyclases.

Toxicological Evaluation of β-Caryophyllene Oil: Subchronic Toxicity in Rats

In a subchronic toxicity study, administration of β-caryophyllene (BCP) oil by oral gavage to Wistar rats at dosages of 0, 150, 450, or 700 mg/kg/d for 90 days, including a 21-day recovery period, did not produce any significant toxicologic manifestations. The study design also included a 28-day interim sacrifice in the control and high-dose groups. The BCP oil test article was well tolerated as evidenced by the absence of major treatment-related changes in the general condition and appearance of the rats, neurobehavioral end points, growth, feed and water intake, ophthalmoscopic examinations, routine hematology and clinical chemistry parameters, urinalysis, and necropsy findings. The no observed adverse effect level was the highest dosage level administered of 700 mg/kg body weight/d for both male and female rats. The study was conducted as part of an investigation to examine the safety of BCP oil for its proposed use in medical food products.

Sesquiterpenes from Essential Oils and Anti-Inflammatory Activity

This review is aimed at presenting relevant information on the therapeutic potential of essential oil sesquiterpenes with anti-inflammatory activity. The data reviewed provide a basis for seeking new anti-inflammatory drugs from natural products that do not exhibit the undesirable side effects often displayed by anti-inflammatory drugs. In this review the experimental models, possible mechanisms of action, and chemical structures of 12 sesquiterpenes are presented.

Relationship between Soil and Essential Oil Profiles in Salvia desoleana Populations: Preliminary Results

Salvia desoleana is a herbaceous perennial shrub endemic of Sardinia (Italy). The leaves are a source of essential oil, used in pharmaceutical and cosmetic industries. The therapeutic function of this species has been associated to the presence of essential oils rich in α/β-pinene, p-cimene, linalool, linalyl acetate and 1,8-cineole. Today the industrial request of Salvia essential oils is increasing and most of the biomass is exploited from the natural populations which are under severe risk of genetic erosion. In order to improve the essential oil production, the study of the environmental parameters that influence composition, quality and quantity of the essential oils, turns out to be necessary. Soil physical and chemical structure represents one of the determinant factors in secondary metabolites production, and could also be involved in volatiles fraction composition in the same species. The main aim of this research was to explore the relationship between essential oil profiles and soil characteristics in S. desoleana populations.

GC/MS analysis performed on the essential oil extracts identified 22 principal compounds, which were extremely variable among the five S. desoleana populations studied. The analysis of the essential oils revealed different compositions in the terpenes fractions: 68.2% of monoterpenes, 27.3% of sesquiterpenes and 4.5% of diterpenes. Analysis of chemical and physical soil parameters at the collection sites revealed that silt and sand contents were correlated with α-pinene and sclareol fractions and the total K2O was significantly correlated to several compounds belonging to the three terpene fractions identified. These results will provide guidelines for the in site conservation and for the improvement of the commercial value of the species.

Increasing phosphorus supply is not the mechanism by which arbuscular mycorrhiza increase attractiveness of bean (Vicia faba) to aphids

Arbuscular mycorrhizal (AM) fungi, important plant mutualists, provide plants with nutrients such as phosphorus (P) in return for carbon. AM fungi also enhance the attractiveness of plants to aphids via effects on emissions of plant volatiles used in aphid host location. We tested whether increased P uptake by plants is the mechanism through which AM fungi alter the volatile profile of plants and aphid behavioural responses by manipulating the availability of P and AM fungi to broad beans (Vicia faba L.) in a multi-factorial design. If AM fungi affect plant volatiles only via increased P acquisition, we predicted that the emission of volatiles and the attractiveness of mycorrhizal beans to aphids would be similar to those of non-mycorrhizal beans supplied with additional P. AM fungi and P addition increased leaf P concentrations by 40 and 24%, respectively. The production of naphthalene was less in mycorrhizal plants, regardless of P addition. By contrast, production of (S)-linalool, (E)-caryophyllene and (R)-germacrene D was less in plants colonized by AM fungi but only in the absence of P additions. The attractiveness of plants to pea aphids (Acyrthosiphon pisum Harris) was positively affected by AM fungi and correlated with the extent of root colonization; however, attractiveness was neither affected by P treatment nor correlated with leaf P concentration. These findings suggest that increased P uptake is not the main mechanism by which mycorrhiza increase the attractiveness of plants to aphids. Instead, the mechanism is likely to operate via AM fungi-induced plant systemic signalling.

Multivariate optimization of a headspace solid-phase microextraction method followed by gas chromatography with mass spectrometry for the determination of terpenes in Nicotiana langsdorffii

A simple and sensitive procedure based on headspace solid-phase microextraction and gas chromatography with mass spectrometry was developed for the determination of five terpenes (α-pinene, limonene, linalool, α-terpineol, and geraniol) in the leaves of Nicotiana langsdorffii. The microextraction conditions (extraction temperature, equilibration time, and extraction time) were optimized by means of a Doehlert design. The experimental design showed that, for α-pinene and limonene, a low temperature and a long extraction time were needed for optimal extraction, while linalool, α-terpineol, and geraniol required a high temperature and a long extraction time. The chosen compromise conditions were temperature 60°C, equilibration time 15 min and extraction time 50 min. The main analytical figures of the optimized method were evaluated; LODs ranged from 0.07 ng/g (α-pinene) to 8.0 ng/g (geraniol), while intraday and interday repeatability were in the range 10-17% and 9-13%, respectively. Finally, the procedure was applied to in vitro wild-type and transgenic specimens of N. langsdorffii subjected to abiotic stresses (chemical and heat stress). With the exception of geraniol (75-374 ng/g), low concentration levels of terpenes were measured (ng/g level or lower); some interesting variations in terpene concentration induced by abiotic stress were observed.

Insect herbivores, chemical innovation, and the evolution of habit specialization in Amazonian trees

Herbivores are often implicated in the generation of the extraordinarily diverse tropical flora. One hypothesis linking enemies to plant diversification posits that the evolution of novel defenses allows plants to escape their enemies and expand their ranges. When range expansion involves entering a new habitat type, this could accelerate defense evolution if habitats contain different assemblages of herbivores and/or divergent resource availabilities that affect plant defense allocation. We evaluated this hypothesis by investigating two sister habitat specialist ecotypes of Protium subserratum (Burseraceae), a common Amazonian tree that occurs in white-sand and terra firme forests. We collected insect herbivores feeding on the plants, assessed whether growth differences between habitats were genetically based using a reciprocal transplant experiment, and sampled multiple populations of both lineages for defense chemistry. Protium subserratum plants were attacked mainly by chrysomelid beetles and cicadellid hemipterans. Assemblages of insect herbivores were dissimilar between populations of ecotypes from different habitats, as well as from the same habitat 100 km distant. Populations from terra firme habitats grew significantly faster than white-sand populations; they were taller, produced more leaf area, and had more chlorophyll. White-sand populations expressed more dry mass of secondary compounds and accumulated more flavone glycosides and oxidized terpenes, whereas terra firme populations produced a coumaroylquinic acid that was absent from white-sand populations. We interpret these results as strong evidence that herbivores and resource availability select for divergent types and amounts of defense investment in white-sand and terra firme lineages of Protium subserratum, which may contribute to habitat-mediated speciation in these trees.

Transfer of metals and metalloids from soil to shoots in wild rosemary (Rosmarinus officinalis L.) growing on a former lead smelter site: human exposure risk

This study aimed at estimating exposition risks to wild rosemary used as herbs in the contaminated area of the former smelting factory of L'Escalette (South of Marseille, France). Metals and metalloids i.e. Pb, As, Sb, Zn, and Cu concentrations were analyzed in soils and in rosemary aerial parts (stems and leaves) on two sites: one heavily contaminated and the other far away from the pollution source, considered as reference. The metal and metalloid transfer into water during the brewing process of herbal tea was also determined. A mixed contamination by the above-cited contaminants was demonstrated in soils of the factory site, with average concentrations of 9253, 1127, 309, 2698 and 32 mg/kg for Pb, As, Sb, Zn and Cu, respectively. However, metals and metalloids' transfer in rosemary aerial parts was limited, as bioaccumulation factors were under 1. Thus, Pb, As and Cu concentrations in leaves were below international regulation limits concerning ingestion of medicinal herbs (no regulation values available for Sb and Zn). This study highlighted that, if contaminated rosemary leaves were ingested, health risks may be limited since acceptable daily intake (ADI) for Pb, As, Sb and Cu (no ADI value available for Zn) will only be reached if very high quantities are consumed. Furthermore, we aimed to establish if this mixed contamination could alter rosemary's essential oil quality, and thereby the compositions of essential oils obtained from individuals on the heavily contaminated soil were compared to those obtained from the reference population. An increased biosynthesis of antioxidant compounds was favored in essential oils from rosemary individuals growing in contaminated site. Although the health risk of a long-term exposition of low level of the mixed contamination by rosemary ingestion is not easy to elucidate, the use of rosemary essential oils from contaminated site appears as safe.

Formation of the unusual semivolatile diterpene rhizathalene by the Arabidopsis class I terpene synthase TPS08 in the root stele is involved in defense against belowground herbivory

Secondary metabolites are major constituents of plant defense against herbivore attack. Relatively little is known about the cell type-specific formation and antiherbivore activities of secondary compounds in roots despite the substantial impact of root herbivory on plant performance and fitness. Here, we describe the constitutive formation of semivolatile diterpenes called rhizathalenes by the class I terpene synthase (TPS) 08 in roots of Arabidopsis thaliana. The primary enzymatic product of TPS08, rhizathalene A, which is produced from the substrate all-trans geranylgeranyl diphosphate, represents a so far unidentified class of tricyclic diterpene carbon skeletons with an unusual tricyclic spiro-hydrindane structure. Protein targeting and administration of stable isotope precursors indicate that rhizathalenes are biosynthesized in root leucoplasts. TPS08 expression is largely localized to the root stele, suggesting a centric and gradual release of its diterpene products into the peripheral root cell layers. We demonstrate that roots of Arabidopsis tps08 mutant plants, grown aeroponically and in potting substrate, are more susceptible to herbivory by the opportunistic root herbivore fungus gnat (Bradysia spp) and suffer substantial removal of peripheral tissue at larval feeding sites. Our work provides evidence for the in vivo role of semivolatile diterpene metabolites as local antifeedants in belowground direct defense against root-feeding insects.

Allelochemicals of Pinus halepensis as drivers of biodiversity in Mediterranean open mosaic habitats during the colonization stage of secondary succession

The Mediterranean region is recognized as a global biodiversity hotspot. However, over the last 50 years or so, the cessation of traditional farming has given way to strong afforestation at the expense of open habitats. Pinus halepensis Miller, known to synthesize a wide range of secondary metabolites, is a pioneer expansionist species colonizing abandoned agricultural land that present high species richness. Here, laboratory bioassays were used to study the potential impact of P. halepensis on plant diversity through allelopathy, and the role of microorganisms in these interactions. Germination and growth of 12 target species naturally present in fallow farmlands were tested according to concentration of aqueous extracts obtained from shoots of young pines (aged about 5 years), with or without the presence of soil microorganisms (autoclaved or natural soil). Under the highest concentrations and autoclaved soil, more than 80 % of target species were germination and/or growth-inhibited, and only two species were non-sensitive. Under more natural conditions (lower extracts concentrations and natural soil with microorganisms), only 50 % of species were still inhibited, one was non-sensitive, and five were stimulated. Thus, microorganisms alter the expression of allelochemicals released into the ecosystem, which highlights their key role in chemical plant-plant interactions. The results of allelopathic experiments conducted in the lab are consistent with the community patterns observed in the field. These findings suggest that allelopathy is likely to shape vegetation composition and participate to the control of biodiversity in Mediterranean open mosaic habitats.

Seasonal Variations in the Composition of the Essential Oils of Rosemary (Rosmarinus officinalis, Lamiaceae)

Seasonal variations in the composition of the essential oils obtained from rosemary plants of the same genotype cultivated in Belgrade were determined by GC and GC/MS. The main constituents were camphor (18.2 - 28.1%), 1,8-cineole (6.4-18.0%), α-pinene (9.7-13.5%), borneol (4.4-9.5%), camphene (5.1-8.7%), β-pinene (2.1-8.1%), β-phellandrene (4.6-6.5%), myrcene (3.4-5.9%) and bornyl acetate (0.2-7.9%). Cluster analysis showed that 16 samples that had been collected each month during the vegetative cycle can be separated into three main clades with different compositions of essential oils. In the shoots with fruits (‘fruits’ - Clade I) and shoots with developed leaves (‘Old shoots’ - Clade III) camphor is dominant. In shoots with young and incompletely developed leaves (‘young shoot’ - Clade II) camphor and 1,8-cineole had almost the same concentration. The fact that the same genotype during the growing seasons can synthesize oils that are so different that they can be classified as different chemotypes confirms the opinion that the chemical composition of essential oils sometimes critically depends on the time of collection. Also, for the definition of chemotypes it is not enough to base this on a chemical analysis of an oil from one phenophase only.