Compounds from myrtle flowers as antibacterial agents and SARS-CoV-2 inhibitors: In-vitro and molecular docking studies

Plants and their related phytochemicals play a key role in the treatment of bacterial and viral infections, which inspire scientists to design and develop more efficient drugs starting from the phytochemical active scaffold. This work aims to characterize the chemical compounds of Myrtus communis essential oil (EO) from Algeria and to evaluate its in vitro antibacterial effect, as well as the in silico anti-SARS-CoV-2 activity. The chemical profile of hydrodistilled EO from myrtle flowers was determined using GC/MS analysis. The results showed qualitative and quantitative fluctuations and 54 compounds were identified including the main components: α-pinene (48.94%) and 1,8-cineole (28.3%) whereas other minor compounds were detected. The in vitro antibacterial activity of myrtle EO against Gram-negative bacteria was carried out by using the disc diffusion method. The best inhibition zone values ranged between 11 and 25 mm. The results revealed that Escherichia coli (25 mm), Klebsiella oxytoca (20 mm) and Serratia marcescens (20 mm) are the most susceptible strains to the EO which is endowed with a bactericidal effect. Furthermore, the antibacterial and anti-SARS-CoV-2 activities were investigated by the means of molecular docking (MD) study, in addition to ADME(Tox) analysis. The phytochemicals were docked against four targets: E. coli topoisomerase II DNA gyrase B (PDB: 1KZN), SARS-CoV-2 Main protease (PDB: 6LU7), Spike (PDB: 6ZLG) and angiotensin-converting enzyme II ACE2 (PDB: 1R42). The MD investigation revealed that 1,8-cineole could be the main phytochemical associated with the antibacterial activity of EO; s-cbz-cysteine, mayurone and methylxanthine were found the most promising phytochemicals against SARS-CoV-2; The ADME(Tox) analysis has shown their good druggability with no Lipinski's rule violation.

Generation of Highly Antioxidant Submicron Particles from Myrtus communis Leaf Extract by Supercritical Antisolvent Extraction Process

Submicron particles have been produced from an ethanolic extract of Myrtus communnis leaves using supercritical carbon dioxide technology, hereinafter referred to as Supercritical Antisolvent Extraction (SAE). The influence of pressure (9-20 MPa), temperature (308 and 328 K) and injection rate (3 and 8 mL/min) on the particles' precipitation has been investigated, and it has been confirmed that increases in pressure and temperature led to smaller particle sizes. The obtained particles had a quasi-spherical shape with sizes ranging from 0.42 to 1.32 μm. Moreover, the bioactivity of the generated particles was assessed and large contents of phenolic compounds with a high antioxidant activity were measured. The particles were also subjected to in vitro studies against oxidative stress. The myrtle particles demonstrated cytoprotective properties when applied at low concentrations (1 μM) to macrophage cell lines.

Gallomyrtucommulones G and H, New Phloroglucinol Glycosides, from Bioactive Fractions of Myrtus communis against Staphylococcus Species

Myrtaceae family is a continuous source of antimicrobial agents. In the search for novel antimicrobial agents against Staphylococcus species, bioactive fractions of Myrtus communis L., growing in the Sardinia island (Italy) have been investigated. Their phytochemical analysis led us to isolate and characterize four alkylphloroglucinol glycosides (1–4), three of them gallomyrtucommulones G–H (1,2), and myrtucommulonoside (4) isolated and characterized for the first time. The structures of the new and known compounds, endopreroxide G3 (5), myricetin-3-O-glycosides (6,7) were determined based on the spectroscopic evidence including 1D-/2D-NMR and HR-MS spectrometry. Enriched fractions as well as pure compounds were tested for their antimicrobial activity by broth micro-dilution assay against Staphylococcus epidermidis and S. aureus. Results reported herein demonstrated that gallomyrtucommulone G (1) showed a selective antimicrobial activity against both S. aureus strains (ATCC 29213 and 43300) until 16 μg/mL while gallomyrtucommulone D (3) showed the best growth inhibition value at 64 μg/mL.

Assessment of anthelmintic potentials of Myrtus communis against Haemonchus contortus and Heligmosomoides polygyrus

Anthelmintic resistance in grazing livestock systems has been spreading worldwide in prevalence and severity. Therefore, alternative measures including the use of herbal anthelmintic is considered as one of the successful approaches for the control of anthelmintic resistance. In the present report, we describe the chemical constituents of Myrtus communis essential oil, its in vitro anthelmintic effect against the most pathogenic gastrointestinal parasite of sheep; Haemonchus contortus and its in vivo anthelmintic potential using an in vivo gastrointestinal parasite model of rodents; i.e. Heligmosomoides polygyrus. Chromatographic analyzes of the essential oil (EO) extracted from the leaves of M. communis have shown that this oil was composed mainly of a α-pinene (33.59%), eucalyptol (23.85%) and limonene (14.70%). Regarding the in vitro anthelmintic potential, the ovicidal effect was confirmed in an egg hatch inhibition assay at IC₅₀ = 0.7 mg/mL and with 95.83% of immobility of adult worm's after 8 h of exposure to 2 mg/mL of M. communis EO. The anthelmintic capacity of M. communis EO was also confirmed by in vivo assays conducted against the murine parasite H. polygyrus. In fact, at 1200 mg/kg bw of M. communis EO, a reduction of 99.70% in faecal egg counts was observed after 7 days of oral treatment, together with a 71.12% reduction in total worm counts. Based on the obtained results, M. communis EO showed relevant in vitro and in vivo anthelmintic effects against gastro-intestinal parasites.

Soil Inoculation With Beneficial Microbes Buffers Negative Drought Effects on Biomass, Nutrients, and Water Relations of Common Myrtle

Common myrtle (Myrtus communis L.) occurs in (semi-)arid areas of the Palearctic region where climate change, over-exploitation, and habitat destruction imperil its existence. The evergreen shrub is of great economic and ecological importance due to its pharmaceutical value, ornamental use, and its role in urban greening and habitat restoration initiatives. Under greenhouse conditions, we investigated the effect of soil inoculation with arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) on biomass allocation, water relations, and nutritional status of drought-stressed myrtle seedlings. Single and dual AMF (Funneliformis mosseae and Rhizophagus irregularis) and PGPR (Pseudomonas fluorescens and P. putida) soil inoculations were applied to myrtle seedlings growing under different soil water regimes (100, 60, and 30% of field capacity) for 6 months using a full factorial, completely randomized design. AMF and PGPR treatments, especially dual inoculations, alleviated negative drought effects on biomass and morpho-physiological traits, except for water-use efficiency, which peaked under severe drought conditions. Under the greatest soil water deficit, dual inoculations promoted leaf biomass (104%-108%), root biomass (56%-73%), mesophyll conductance (58%), and relative water content (1.4-fold) compared to non-inoculated controls. Particularly, dual AMF and PGPR inoculations stimulated nutrient dynamics in roots (N: 138%-151%, P: 176%-181%, K: 112%-114%, Ca: 124%-136%, and Mg: 130%-140%) and leaves (N: 101%-107%, P: 143%-149%, K: 83%-84%, Ca: 98%-107%, and Mg: 102%-106%). Our findings highlight soil inoculations with beneficial microbes as a cost-effective way to produce highly drought resistant seedling stock which is vital for restoring natural myrtle habitats and for future-proofing myrtle crop systems.

Chemical composition, antibiofilm, cytotoxic, and anti-acetylcholinesterase activities of Myrtus communis L. leaves essential oil

BACKGROUND

The potential of essential oils (EOs) and of their principal constituents for eradication of biofilm and at the same time the research of new potential acetylcholinesterase inhibitors is gaining increasing interest in last years. The aims of this study were to determine the chemical composition and to evaluate the antibacterial, cytotoxic, and anti-acetylcholinesterase properties of Myrtus communis leaves essential oil and its main constituents.

METHODS

Essential oil was obtained by hydrodistillation of M. communis L. leaves and was analyzed by GC and GC-MS. The antimicrobial activity was carried out against both gram-negative and gram-positive bacteria. The microdilution method was used to estimate the minimum inhibitory concentrations (MICs). Then, the capacity of essential oil and its main constituent to inhibit biofilm growth, with the method of O'Toole and Kolterand, and the metabolic activity of biofilm cells through the MTT colorimetric method were evaluated at different times. Moreover, was studied the potential cytotoxic activity against SH-SY5Y cell line with MTT assay and the anti-acetylcholinesterase activity using Ellman's assay.

RESULTS

Myrtenyl-acetate, 1,8 cineole, α-pinene, and linalool were the main components in the EO. The myrtle EO, at the minimum tested dose (0.4 mg/ml), inhibited S. aureus biofilm by 42.1% and was capable of inhibiting the biofilm cell metabolism in all tested strains, except Staphylococcus aureus. Moreover, the EO showed good cytotoxic and anti-acetylcholinesterase activities IC₅₀ of 209.1 and 32.8 μg/ml, respectively.

CONCLUSIONS

The results suggest that myrtle EO and its main constituents could be used as possible products that could act against the resistant pathogenic species E. coli, P. aeruginosa, L. monocytogenes and S. aureus, on the other hand, as possible coadjutants in the treatment of neurological diseases.

Hyperforin and Myrtucommulone Derivatives Act as Natural Modulators of Wnt/β-Catenin Signaling in HCT116 Colon Cancer Cells

The therapeutic activities of natural plant extracts have been well known for centuries. Many of them, in addition to antiviral and antibiotic effects, turned out to have anti-tumor activities by targeting different signaling pathways. The canonical Wnt pathway represents a major tumorigenic pathway deregulated in numerous tumor entities, including colon cancer. Here, we investigated the acylphloroglucinols hyperforin (HF) from St. John's wort (Hypericum perforatum L.) and myrtucommulone A (MC A) from myrtle (Myrtus communis) and semi-synthetic derivatives thereof (HM 177, HM 297, HM298) for their effects on Wnt/β-catenin signaling. None of these substances revealed major cytotoxicity on STF293 embryonic kidney and HCT116 colon carcinoma cells at concentrations up to 10 μM. At this concentration, HF and HM 177 showed the strongest effect on cell proliferation, whereas MC A and HM 177 most prominently inhibited anchorage-independent growth of HCT116 cells. Western blot analyses of active β-catenin and β-catenin/TCF reporter gene assays in STF293 cells revealed inhibitory activities of HF, MC A and HM 177. In line with this, the expression of endogenous Wnt target genes, Axin and Sp5, in HCT116 cells was significantly reduced. Our data suggest that the acylphloroglucinols hyperforin, myrtucommulone A and its derivative HM 177 represent potential new therapeutic agents to inhibit Wnt/β-catenin signaling in colon cancer.

Effects of Myrtus communis L. Extract and Apocynin on Lens Oxidative Damage and Boron Levels in Rats with a High Fat-Diet

Objectives:

Nutritional obesity causes oxidant damage in the body and cataract formation in the lenses by increasing the formation of free radicals. Myrtus communis leaf extracts (Myr) have antioxidant properties, and apocynin (Apo) is an effective NADPH-oxidase inhibitor. The data on tissue boron levels are quite lacking. The aim of this novel study was to investigate the effects of Myr and Apo treatment on boron levels and oxidative lens damage in rats fed a high-fat diet (HFD).

Materials and Methods:

Wistar albino male rats were randomly divided into four groups: the control group, HFD group, HFD + Myr group, and HFD + Apo group. Body weight and blood lipids were determined before and after the experiment. After decapitating the rats, the lenses were removed and homogenized. Catalase (CAT) and superoxide dismutase (SOD) activities and boron, malondialdehyde (MDA), and reduced glutathione (GSH) levels in the lens homogenates were determined.

Results:

The HFD increased serum triglyceride (p<0.05), total cholesterol level (p<0.001), body weight (p<0.001), and lens MDA levels (p<0.01) and decreased lens GSH (p<0.05) and boron level (p<0.01), SOD (p<0.001), and CAT activity (p<0.001). However, Myr and Apo treatment reduced the rats’ body weight (p<0.001), serum triglyceride (p<0.05), and total cholesterol level (p<0.001) and increased lens boron (p<0.01; p<0.001), GSH levels (p<0.05; p<0.01), and CAT activity (p<0.001).

Conclusion:

Both Myr and Apo may be able to reduce oxidative stress in the lenses of obese rats caused by HFD by increasing boron levels.

Ethanol Extract of Myrtle (Myrtus communis L.) Berries as a Remedy for Streptozotocin-Induced Oxidative Stress in Rats

Streptozotocin (STZ) is an antitumor antibiotic indicating in the treatment of metastatic islet cell carcinoma of the pancreas. It is also used as a tool to create experimental diabetes models. The STZ exposure at a high dose causes severe damage to cells of humans and other mammals. The goal of the present study was to assess the protective effects of the ethanol extract of the Myrtle (Myrtus communis L.) berries, which is a well-known medicinal plant due to its rich phenolic content and beneficial effects on health, against STZ-induced oxidative stress in the diabetic rats.Diabetes was induced by STZ (40 mg/kg, i.p.) in the rats. After diabetes induction, a significant increase in alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), and blood glucose levels as well as a significant decrease in superoxide dismutase (SOD) activities and glutathione (GSH) levels was observed. The rats were treated to three different ethanol extracts of Myrtle berries (0.25, 0.5, and 1 g/kg) by oral gavage for 14 days. At the end of the experiment, ALT, AST, MDA, and blood glucose levels of the rats significantly decreased while significant increases in GSH levels and SOD activities were observed.We believe that our findings may contribute to the development of new drugs in the treatment of many global disorders due to the antioxidant activity of the ethanol extract of Myrtus communis L. berries.

Chemical Variability of Moroccan Myrtle Oil

Thirty-three oil samples isolated from aerial parts of Myrtus communis L. harvested in seven localities, from Northern to Central Morocco, have been analyzed by combination of chromatographic and spectroscopic techniques. The 33 compositions have been subjected to statistical analysis, hierarchical cluster analysis (HCA) and principal component analysis (PCA). Two groups have been differentiated on the basis of their myrtenyl acetate and α-pinene contents and each one was sub-divided in two sub-groups according to the contents of 1,8-cineole and linalool. The compositions of our 33 myrtle oil samples may be named as follow by their main components: sub-group IA (13/33): α-pinene/1,8-cineole/linalool; sub-group IB (6/33): 1,8-cineole/α-pinene; sub-group IIA (10/33): 1,8-cineole/myrtenyl acetate; sub-group IIB (4/33): myrtenyl acetate.

[Discussion on traditional Chinese medicine properties of Myrtus communis leaves based on literature analysis and Chinese medicine theory]

Myrtus communis is a traditional medicinal aromatic plant in the Mediterranean. At present, the plant has been introduced and cultivated in the southern part of China, and it is mostly used for ornamental or cosmetic purposes. Based on literature analysis and the theory of Chinese medicine, we discussed the medicinal parts and properties of M. communis in this paper to provide a theoretical basis for exploring the medicinal value of M. communis and its compatibility with traditional Chinese medicines. Literatures were searched from Web of Science(core collection), PubMed, CNKI, VIP and Wanfang by using the set conditions as key words. Then the obtained literatures were screened and classified. Finally, a total of 376 articles were included, consisting of 44 reviews, 54 germplasm resources, 78 chemical researches, 48 studies on application, extraction, or quality, 18 human trials, 132 pharmacological studies, and 2 safety studies. Based on literature analysis and theories of Chinese medicine, the leaves of M. communis were finally selected as the medicinal part of Chinese medicine, and the traditional Chinese medicine properties of M. communis leaves were deduced as pungent, bitter, and cool. The channel tropisms of M. communis leaves included lung, liver, and large intestine, with functions of detoxifying, resolving a mass, and insecticide. It was used for mouth sores, vaginal itching, hemorrhoids and warts, etc.; appropriate amount shall be applied for external use, and the decoction form shall be used for washing the affected parts; 3-12 g equivalent product shall be used in decoction, and this herb shall be put into the decoction in a later stage. The clarification of the medicinal parts of M. communis, and the determination of the Chinese medicine properties of M. communis leaves would lay a theoretical foundation for its compatibility and application with Chinese medicines, and can do more contribution to the medical and healthcare industry in our country.

Myrtus communis Essential Oil; Anti-Parasitic Effects and Induction of the Innate Immune System in Mice with Toxoplasma gondii Infection

Background: Myrtus communis (M. communis) is a wild aromatic plant used for traditional herbal medicine that can be demonstrated in insecticidal, antioxidant, anti-inflammatory, and antimicrobial activity of its essential oils (MCEO). Aim: The present study aimed to evaluate the prophylactic effects of M. communis essential oil (MCEO) against chronic toxoplasmosis induced by the Tehran strain of Toxoplasma gondii in mice. Methods: Gas chromatography/mass spectrometry (GC/MS) analysis was performed to determine the chemical composition of MCEO. Mice were then orally administrated with MCEO at the doses of 100, 200, and 300 mg/kg/day and also atovaquone 100 mg/kg for 21 days. On the 15th day, the mice were infected with the intraperitoneal inoculation of 20–25 tissue cysts from the Tehran strain of T. gondii. The mean numbers of brain tissue cysts and the mRNA levels of IL-12 and IFN-γ in mice of each tested group were measured. Results: By GC/MS, the major constituents were α-pinene (24.7%), 1,8-cineole (19.6%), and linalool (12.6%), respectively. The results demonstrated that the mean number of T. gondii tissue cysts in experimental groups Ex1 (p < 0.05), Ex2 (p < 0.001) and Ex3 (p < 0.001) was meaningfully reduced in a dose-dependent manner compared with the control group (C2). The mean diameter of tissue cyst was significantly reduced in mice of the experimental groups Ex2 (p < 0.01) and Ex3 (p < 0.001). The results demonstrated that although the mRNA levels of IFN-γ and IL-12 were elevated in all mice of experimental groups, a significant increase (p < 0.001) was observed in tested groups of Ex2 and Ex3 when compared with control groups. Conclusion: The findings of the present study demonstrated the potent prophylactic effects of MCEO especially in the doses 200 and 300 mg/kg in mice infected with T. gondii. Although the exceptional anti-Toxoplasma effects of MCEO and other possessions, such as improved innate immunity and low toxicity are positive topics, there is, however, a need for more proof from investigations in this field.

Antibacterial Triketone-Phloroglucinol-Triketone Adducts from Myrtus communis

Myrtucyclitones A-C ((+)- and (-)-1-3), three pairs of new triketone-phloroglucinol-triketone hybrids were isolated from the plant Myrtus communis. Their structures with absolute configurations were established by NMR analysis and chemical calculations. Myrtucyclitones B and C exhibited remarkable antibacterial effect.

Role of Anti-Inflammatory, Reactive Oxygen Species Scavenging Activity and Nematicidal Properties of Myrtle Berry Seeds on Helminthiasis Treatment

This study was undertaken to investigate the involvement of the reactive oxygen species (ROS) and proinflammatory cytokine production in the pathogenicity of gastrointestinal nematode Heligmosomoides polygyrus in mice and also the protective effect of myrtle (Myrtus communis L.) berry seeds aqueous extract (MBSAE). With this aim, Swiss Albino mice were divided into four groups of 10 animals each: control, helminthiasis, helminthiasis + MBSAE, and helminthiasis + Albendazole. The animals were infected with infective third larval stage (L3) of H. polygyrus by oral administration. Mice were treated with bidistilled water, MBSAE (100 mg/kg, b.w., p.o.) or Albendazole (100 mg/kg, b.w., p.o.). We have demonstrated that MBSAE (100 mg/kg, b.w., p.o.) significantly reduced the total mean adult worms compared with the infected and nontreated group. Moreover, hematological parameters, intestinal ROS such as hydrogen peroxide (H₂O₂), hydroxyl radical (OH^•), and superoxide anion (O₂^•-), as well as serum cytokines such as interleukin (IL)-1β and IL-6 were analyzed. We have shown that H. polygyrus infection has disrupted all these biochemical parameters and that MBSAE treatment has significantly corrected these disturbances. The effect of plant extract was comparable to the standard drug albendazole. Therefore, MBSAE appeared to be a promising agent for the control of intestinal helminthiasis.

Highly Concentrated Multifunctional Silver Nanoparticle Fabrication through Green Reduction of Silver Ions in Terms of Mechanics and Therapeutic Potentials

BACKGROUND

Green synthesis of silver nanoparticles (AgNPs) is limited to produce AgNPs with only relatively low concentrations, and is unsuitable for large-scale productions. The use of Myrtus communis (MC) leaf methanolic extract (rich in hydrolyzable tannins) has been recommended to resolve the issues related to the aggregation of nanoparticles at high concentrations of silver ions with added facet of antioxidant properties.

METHODS

The produced highly concentrated MC-AgNPs were characterized by using imaging and spectroscopic methods. Subsequently, antioxidant, anticancer and antifungal activities of the nanoparticles were evaluated.

RESULTS

The thermogravimetric analysis and energy dispersive spectroscopy quantitative results suggested that the nanoparticles are biphasic in nature (bio-molecule + Ag0) and layered in structure, suggesting the formation of nanoparticles through a different mechanism than those described in the literature. MC-AgNPs showed greater scavenging activity of nitric oxide and iron (II) chelating ability than the extract. It also showed good reducing power compared to the standard antioxidant. Remarkable anticancer activity of MC-AgNPs (IC50 = 5.99µg/mL) was found against HCT-116 (human colon carcinoma) cell lines after 24h exposure with a therapeutic index value 2-fold higher than the therapeutic index of standard doxorubicin. Furthermore, distinct antifungal activity (MIC = 4µg/mL) was found against Candida krusei.

CONCLUSION

The current method outperforms the existing methods because it produces a large amount of multifunctional nanoscale hybrid materials more efficiently using natural sources; thus, it may be used for diverse biomedical applications.

The Effect of Myrtus communis Aqueous Extract-Containing Gel on Wound Healing in Streptozotocin-Induced Diabetic Rats

BACKGROUND

The medicinal plant Myrtus communis L. (Myrtle) has properties, including anti-inflammatory and wound healing in Persian Medicine.

OBJECTIVE

The objective of this study was to explore the wound healing potential of the local application of a gel containing aqueous extract of the plant berry in streptozotocin (STZ)-induced diabetic rats.

METHODS

Seven days after diabetes establishment, full-thickness excision skin wounds were made in normal and diabetic rats where treated groups received topical application of a gel containing 6% aqueous extract of myrtle berries for 3 weeks. The rate of wound healing and the level of epidermal and dermal maturation in the wound tissue were determined.

RESULTS

The results showed that after 3 and 7 days of wound injury, the gel significantly improved wound healing by accelerating epidermal and dermal maturation in diabetic rats with no significant effect in the control group. However, the wounds of all groups almost completely healed after 3 weeks.

CONCLUSION

These results demonstrate that aqueous extract of myrtle possesses a definite wound healing potential in diabetic conditions. The present findings may suggest the use of topical myrtle berries aqueous extract gel 6% to treat and manage intractable diabetic wounds.

Investigating In Vitro Antibacterial Activities of Medicinal Plants Having Folkloric Repute in Ethiopian Traditional Medicine

Medicinal plants are targeted in the search for new antimicrobial agents. Nowadays, there is an alarmingly increasing antimicrobial resistance to available agents with a very slow development of new antimicrobials. It is, therefore, necessary to extensively search for new agents based on the traditional use of herbal medicines as potential source. The antibacterial activity of 80% methanol extracts of the leaves of Verbena officinalis (Vo-80ME), Myrtus communis (Mc-80ME), and Melilotus elegans (Me-80ME) was tested against 6 bacterial isolates using agar well diffusion technique. In each extract, 3 concentrations of 10, 20, and 40 mg/well were tested for each bacterium. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also determined. Vo-80ME and Mc-80ME exhibited promising antibacterial activity against Staphylococcus aureus with the highest zone of inhibition being 18.67 and 26.16 mm, respectively at concentration of 40 mg/well. Regarding gram-negative bacteria, Vo-80ME exhibited an appreciable activity against Escherichia coli and Salmonella typhi. Mc-80ME displayed remarkable activity against all isolates including Pseudomonas aeruginosa with the maximum zone of inhibition being 22.83 mm. Me-80ME exhibited better antibacterial activity against E coli, but its secondary metabolites had little or no activity against other gram-negative isolates. The MIC values of Vo-80ME ranged from 0.16 to 4.00 mg/mL. The lowest MIC was observed in Mc-80ME, with the value being 0.032 mg/mL. Mc-80ME had bactericidal activity against all tested bacterial isolates. Mc-80ME showed remarkable zone of inhibitions in all tested bacterial isolates. Besides, Vo-80ME showed good antibacterial activity against S aureus, E coli, and S typhi. Conversely, Me-80ME has shown good activity against E coli only. Generally, M communis L and V officinalis have good MIC and MBC results.

GC-MS analysis of Myrtus communis extract and its antibacterial activity against Gram-positive bacteria

BACKGROUND

Myrtus communis is a typical plant of Mediterranean area. The different parts of this plant such as berries, branches, and leaves have been used worldwide as a traditional/folk medicine for the treatment of various ailments and diseases.

METHODS

Ethanolic leaf extract of the plant was prepared by Soxhlet extraction method. Zone of inhibition, minimum inhibitory concentration and minimal bactericidal concentration were determined by well diffusion method and microplate alamar blue assay. GC-MS analysis was carried out to identify the compounds present in the extract. Microscopy and ImageJ software were used respectively for morphology and cell-length measurements. GraphPad Prism was used for statistical analysis.

RESULTS

The ethanolic extract showed strong inhibitory effect against Gram-positive and acid-fast bacteria with significant inhibition-zone size (9-25 mm), MIC (4.87-78 μg/ml), as well as MBC (0.3-20 mg/ml). However, no effect was observed on the growth of Gram-negative bacteria. The growth inhibition was found to be associated with the damage of cell wall as the extract-treated cells were sensitive to cell wall-targeting antibiotics and displayed the cell wall damage-depicting morphological defects. GC-MS analysis confirmed the presence of novel compounds in addition to the most representative compounds of the essential oils/extracts of M. communis of other country origins.

CONCLUSION

These results demonstrate that M. communis leaf extract could be the source of compounds to be used for the treatment of Gram-positive bacterial infections. This is the first report, which provides insights into the mechanism of action of the extract in inhibiting the growth of Gram-positive bacteria.

Hemostatic activity of aqueous extract of Myrtus communis L. leaf in topical formulation: In vivo and in vitro evaluations

ETHNOPHARMACOLOGICAL RELEVANCE

Myrtus communis L. (MC) is a well-known medicinal plant in traditional Persian medicine, which contains a large amount of phenolic compounds (mainly hydrolyzable tannins). As mentioned in ancient literature, MC was widely used to control bleeding in every part of the body. Nevertheless, there is no pharmacological study on the anti-hemorrhagic activity of this plant till now.

AIM OF THE STUDY

The current in vivo and in vitro study aimed at evaluating the hemostatic activity of M. communis aqueous leaf extract (MCE) in topical formulation.

MATERIALS AND METHODS

Two parameters of bleeding time and amount in tail bleeding model were measured in vivo in rats treated with MCE (1%, 2.5%, 5%, 7.5%, 10%, 15%, and 20% w/v), 5% M. communis aqueous leaf extract gel (G), tannic acid (TA) (1%, 2.5%, 5%, 7.5%, and 10%), normal saline (NS), and the Monsel's solution (MS), a commercial hemostatic agent. Also, the effect of 5% MCE and 5% TA on PT (prothrombin time) and aPTT (activated partial thromboplastin time) as well as protein precipitation and platelet aggregation were assessed in vitro.

RESULTS

In the rat-tail bleeding model, bleeding time and amount significantly (P < 0.001) reduced by the application of 5% MCE solution on the cut tail compared with the NS group. The bleeding time and amount in the MS group were not significantly different from those of the 5% MCE group. Platelet microaggregates were detected by fluorescent microscope. PT and aPTT values increased >120 s and >180 s by 5% MCE, respectively. Also, protein precipitation and significant reduction in serum proteins were observed in the 5% MCE group.

CONCLUSION

The current study provided new insights into the hemostatic effect of MCE, which may be partially mediated by platelet aggregation activity. Hence, it could be evaluated as the resource of new plant origin hemostatic agent.

In vitro evaluation on the scolicidal effect of Myrtus communis L. and Tripleurospermum disciforme L. methanolic extracts

Hydatid disease, a zoonotic disease, is still endemic in many developing countries that is caused by the metacestode of Echinococcus (E.) granulosus. Surgical management is one of the best choices for the treatment of the hydatidosis and using effective scolicidal agents during hydatid surgery is essential to prevent the secondary infection. The aim of the present in vitro study was to evaluate the scolicidal effect of the methanolic extract of Myrtus communis and Tripleurospermum disciforme against protoscoleces of hydatid cyst. Protoscoleces of E. granulosus were aspirated aseptically from infected livers. Various concentrations of M. communis and T. disciforme extracts at different exposure times were examined for their scolicidal activity. Normal saline and silver nitrate were used as negative and positive groups, correspondingly. The viability of protoscoleces was evaluated by 0.1% eosin. The result of the current study indicated that the highest scolicidal effect (100%) of M. communis was obtained at 100 and 50 mg/ml concentrations and LC50 in 10, 20 and 30 min were 11.64 mg/ml, 7.62 mg/ml, and 6.47 mg/ml respectively. The scolicidal activity of T. disciforme was negligible even at high concentration. The findings have shown that the scolicidal activity of M. communis against echinococcosis protoscoleces was strong, while the T. disciforme extract showed fewer effects. However, further studies are required for identification of the active ingredients in the extract and its safety on cells in effective concentrations.

Evaluation of the protective effect of Myrtus communis in scopolamine-induced Alzheimer model through cholinergic receptors

Alzheimer's disease is a progressive neurodegenerative disorder causing common health problem with increasing age. Evidences show that the key symptoms of AD are mainly caused by cholinergic system dysfunction which has a role in cognitive disorders. Cholinergic pathways especially muscarinic receptors like M₁ subtype also have a major role in learning, memory, cognitive functions and emotional state. There is no available permanent treatment currently to cure AD or to change its progression. This study was designed to investigate the factors that play important role in pathogenesis of AD and to compare the effects of Galantamine treatment with effects of Myrtus communis treatment. The expression level of M₁, ACh, BDNF; AChE activity, GSH level, MDA and MPO activity and AChE gene expression were investigated in scopolamine-induced rat model. Results showed that, administration of MC significantly improves the SCOP-induced reduction of latency and object recognition time; increasing BDNF, M₁ and ACh receptor expression levels in the different brain regions. Additionally, MC showed an increased in AChE by enhancing GSH activity and reducing MDA level and MPO activity. In conclusion MC considered as a possible novel therapeutic approach that can be a valuable alternative way in the prevention and treatment of AD.

Development of New Analytical Microwave-Assisted Extraction Methods for Bioactive Compounds from Myrtle (Myrtus communis L.)

The phenolic compounds and anthocyanins present in myrtle berries are responsible for its beneficial health properties. In the present study, a new, microwave-assisted extraction for the analysis of both phenolic compounds and anthocyanins from myrtle pulp has been developed. Different extraction variables, including methanol composition, pH, temperature, and sample–solvent ratio were optimized by applying a Box–Behnken design and response surface methodology. Methanol composition and pH were the most influential variables for the total phenolic compounds (58.20% of the solvent in water at pH 2), and methanol composition and temperature for anthocyanins (50.4% of solvent at 50 °C). The methods developed showed high repeatability and intermediate precision (RSD < 5%). Both methods were applied to myrtle berries collected in two different areas of the province of Cadiz (Spain). Hierarchical clustering analysis results show that the concentration of bioactive compounds in myrtle is related to their geographical origin.

The antibacterial effect of aquatic and methanolic extract of Myrtus communis on Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia

BACKGROUND AND OBJECTIVES

Anaerobic Gram negative bacteria are the main cause of periodontal destruction. It has been shown that Myrtus communis have anti-bacterial activity on Gram positive and Gram negative bacteria. The aim of this study was to determine the antibacterial effect of aquatic and methanolic extract of Myrtus communis on some of the oral Gram-negative bacteria.

MATERIALS AND METHODS

The antibacterial effect of aquatic and methanolic extracts of Myrtus communis was determined using disk diffusion method at different concentrations from 10 to 500 mg/ml. The diameter of inhibition zones were determined. The MIC was defined using the standard broth macrodilution method. The results of the study were reported descriptively.

RESULTS

The aquatic extract of Myrtus communis from 20 to 500 mg/ml had antibacterial effect on Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia. The methanolic extract from 10 to 500 mg/ml had antibacterial effect on A. actinomycetemcomitans, P. gingivalis and P. intermediate. The MIC was achieved at 10 mg/ml, 10 mg/ml and 10 mg/ml for aquatic and methanolic extracts of Myrtus communis on A. Actinomycetemcomitans, P. Gingivalis and P. Intermediate, respectively.

CONCLUSION

Aquatic and methanolic extracts of Myrtus communis had antibacterial effect on P. gingivalis, A. actinomycetemcomitans and P. intermediate. Most concentrations of aqueous extract were effective on bacteria, so, providing an alcoholic extract, that is a time consuming and costly method, does not seem necessary.

Using Thymus carmanicus and Myrtus communis essential oils to enhance the physicochemical properties of potato chips

The aim of this study was to evaluate the antioxidant effects of the essential oils of Myrtus communis leaves and Thymus caramanicus aerial parts in order to improve the physicochemical properties of potato chips. Sunflower oil without any antioxidant (control group) was fortified with BHA or TBHQ antioxidants (200 ppm), and M. communis or T. caramanicus essential oils (3,000 ppm). The effects of the antioxidant behavior of these compounds on the physicochemical properties of potato chips were analyzed by measuring peroxide value (PV), acid value (AV), and thiobarbituric acid (TBA). In addition, changes occurring in oxidation stability, texture, and color were evaluated. The results revealed that samples containing either M. communis or T. carmanicus showed a significant decrease in PV, as compared to the control sample. Compared with the control, the extracted oil of potato chips with M. communis or T. carmanicus led to the significant reduction in AV (p < .05). The results also revealed the addition of the essential oils of M. communis or T. carmanicus was obviously effective in preventing the TBA increasing value. Based on the results obtained by the Rancimat test, either T. carmanicus or M. communis essential oils could significantly increase the shelf-life of potato chips, as compared with the control sample (p < .05). The hardness of potato chips was decreased in M. communis or T. carmanicus groups (p < .05), as compared to the control sample. Neither M. communis nor T. carmanicus essential oils had any negative effects on the lightness values, as compared to the control (p > .05). Based on the results, the physicochemical properties of potato chips could be improved with the addition of these essential oils.

Evaluation of the lifespan extension effects of several Turkish medicinal plants in Caenorhabditis elegans

Research on longevity is important to both prolong lifespan and support healthy aging. Natural products are widely being utilized and used as new resources for drug molecules. Caenorhabditis elegans is an advantageous organism for longevity research and age-related diseases. In this study, we tested a number of plant extracts for their effects on C. elegans longevity. In lifespan assays, agesynchronized wild-type C. elegans specimens were treated with different concentrations of plant extracts. Plant extracts were prepared as either infusions or decoctions, similar to their traditional utilization. Hedera helix L. (Araliaceae) extended lifespan in worms in a concentration-dependent manner. The mean survival rates in the H. helix-treated groups were significantly higher, by 23.7% when applied at 1000 µg/mL, 16% when applied at 500 µg/mL, and 16% when applied at 250 µg/mL, compared to the control group. HPLC analysis identified chlorogenic acid as the major component of H. helix. Salvia verticillata L. (Lamiaceae) and Myrtus communis L. (Myrtaceae) treatments resulted in median lifespan extension. Maximum lifespan was extended in worms by Rubus sanctus Schreb. (Rosaceae) treatment. This study provided the first evidence demonstrating the possible lifespan-extending effects of a group of Turkish medicinal plants in an in vivo model, C. elegans.

Phytoniosome: a Novel Drug Delivery for Myrtle Extract

Traditionally, Myrtus communis (myrtle) has been used for treatment of several kinds of disorders. However, there are some factors, namely, low solubility and permeability, which restrict use of myrtle extract (ME) in medical applications. Regarding these limitations, the aim of the present study was to develop a new niosomal formulation to enhance ME stability and permeability. Briefly, several niosomal formulations were prepared by non-ionic surfactants and cholesterol with different molar ratios. Afterward, size, entrapment efficiency (EE%), release and stability of niosomal myrtle extract (nME) were investigated. The effect of ME and nME on viability of 3T3 cells was evaluated using MTT assay. Antibacterial activity of ME and nME was also assessed against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Micrococcus luteus, and Bacillus subtilis. Sizes of niosomes were 5.3 ± 0.3 to 15.9 ± 2.2 µm with 4.1 ± 0.3 to 26.9 ± 1.7 mV zeta potential. The EE% of niosomes was varied from 45.4% to 93.4%. An in-vitro release study on F5 formulation (Span60: Tween60: cholesterol (3:3:4 molar ratio)) revealed that about 36.9%, 38.5% and 26.7% of phytoconstituents were released within 12 h from acetate cellulose membrane, 0.45 µm, regenerated cellulose membrane, 0.45 µm, and cellophane dialysis sack, 12000 Da, respectively. F5 formulation significantly showed lower toxicity on cells. It had higher antibacterial activity that has been shown by lower MICs and higher zone of inhibition compared to ME. Overall, F5 formulation in the presence of 4% ME produced stable multi lamellar vesicles with optimal in-vitro release and EE%. This formulation also exhibited better antibacterial activity than ME.

Antifungal activity of Myrtus communis against Malassezia sp. isolated from the skin of patients with pityriasis versicolor

The increasing incidence of fungal infections and antifungal resistance has prompted the search for novel antifungal drugs and alternative agents. We explored the antifungal activity of Myrtus communis essential oil (EO) against Malassezia sp. isolated from the skin of patients with pityriasis versicolor. These broad-spectrum antimicrobial activities of M. communis EO and its potent inhibiting activity on Malassezia growth deserve further research with aim to considerate this EO as candidate for topical use in treatment of skin diseases.

Evaluating the effect of Myrtus communis on programmed cell death in hydatid cyst protoscolices

OBJECTIVE

To evaluate the possible involvement of programmed cell death strategy in hydatid cyst protoscolices following treatment with Myrtus communis (M. communis) as an herbal medicine.

METHODS

Protoscolices were aseptically collected from sheep liver hydatid cysts. Evaluating the effect of M. communis extract on programmed cell death and increased activity of caspases 3, 8, and 9 in hydatid cyst protoscolices was conducted by treating the protoscolices with different concentration (5, 50, and 100 mg/mL) of M. communis extract at 37 °C and 5% CO₂ for 4 h by using the Bradford test and ELISA commercial kits.

RESULTS

The extract of M. communis at all concentrations led to initiation of programmed cell death in protoscolices and this effect, was only significant at 50 and 100 mg/mL concentrations, compared to the negative control (P < 0.05). Also, the activity of caspases 3, 8, and 9 in hydatid cyst protoscolices, was shown that the extract at all 3 concentrations could only increase the activity of caspases 3 and 9. Moreover, a significant increase in the activity of caspase 3 was only observed at concentrations 50 and 100 mg/mL by 37.00% and 66.19% while a significant increase in the activity of caspase 9 at the same concentrations was observed by 20.89% and 63.67%, respectively (P < 0.05).

CONCLUSIONS

The extract of M. communis at different concentrations could increase the activity of caspases 3 and 9 and caused programmed cell death in hydatid cyst protoscolices however, this effect was significant at high concentrations of the extract.

Formulation and Optimization of Oral Mucoadhesive Patches of Myrtus Communis by Box Behnken Design

Purpose: Recurrent aphthous stomatitis (RAS) is the most common painful ulcerative disease of oral mucosa happening in ~20% of people. Aimed to develop Myrtus communis L. (Myrtle) containing oral patches, we applied box-behnken design to evaluate the effect of polymers such as Polyvinyl pyrrolidone (PVP), Gelatin, Methylcellulose (MC) and Pectin. Methods: The patches properties such as tensile strength, folding endurance, swelling index, thickness, mucoadhesive strength and the pattern of myrtle release were evaluated as dependent variables. Then, the model was adjusted according to the best fitted equation with box behnken design. Results: The results indicated that preparation of myrtle patch with hydrophilic polymers showed the disintegration time up to 24h and more. Using of polyvinyl pyrrolidone as a water soluble polymer and a pore-former polymer led to faster release of soluble materials from the patch to 29 (min-1). Also it decreases swelling index by increasing the patch disintegration. Gelatin and Pectin, with rigid matrix and water interaction properties, decreased the swelling ratio. Pectin increased the tensile strength, but gelatin produced an opposite effect. Thinner Myrtle patch (about 28µm) was obtained by formulation of methyl cellulose with equal ratio with polyvinyl pyrrolidone or gelatin. Conclusion: Altogether, the analysis showed that the optimal formulation was achieved with of 35.04 mg of Gelatin, 7.22 mg of Pectin, 7.20 mg of polyvinyl pyrrolidone, 50.52 mg of methyl cellulose and 20 mg of Myrtle extract.

Antioxidant effects of extra virgin olive oil enriched by myrtle phenolic extracts on iron-mediated lipid peroxidation under intestinal conditions model

Chelating and free radicals scavenging activities of extra virgin olive oil (EVOO) enriched by Myrtus communis phenolic compounds (McPCs), α-tocopherol and Butylated hydroxytoluene (BHT) were evaluated using chemical assays, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Oxygen radical absorbance capacity (ORAC), and biological model as 2,2'-azobis (2-aminopropane) dihydrochloride (AAPH) or Fe⁺³/Ascorbic acid (Fe⁺³/AsA) system mediated peroxidation of l-α-phosphatidylcholine aqueous dispersions stabilized by bile salts (BS) under simulated intestinal conditions (pH 7.4). McPC-EEVOO increased significantly the neutralization of DPPH radical and AAPH-derived radicals in ORAC assay more than α-tocopherol and BHT. The phospholipid stability increased by a factor of 33.6%, 34.8%, 19.3% and 10.7% for myrtle microwave assisted extraction (MAE) and conventional extraction (CE) extracts, α-tocopherol and BHT, respectively, as compared to the control (EVOO without enrichment) in Fe⁺³/AsA system. But a slightly additive effect was observed when AAPH system was used. Our observation showed that McPCs may interact positively with EVOO to inhibit phospholipid peroxidation, and thus, McPC-EEVOO could be a potential functional food.

Repellency Effect of Essential Oils of some Native Plants and Synthetic Repellents against Human Flea, Pulex irritans (Siphonaptera: Pulicidae)

BACKGROUND

Fleas are important vectors of human and animal disease, and control measures for protection against their bites and flea-borne diseases are necessary.

METHODS

The essential oils (EOs) of four native medicinal plants, Ziziphora tenuiore, Myrtus communis, Achillea wilhelmsii and Mentha piperita were isolated by hydrodistillation technique and analyzed by GC-MC. The repellent activity of EOs and synthetic compounds, DEET and permethrin, were assayed on human subjects against field collected fleas. The effective doses of 50% and 90% of EOs and synthetic compounds were estimated by probit analysis of dose and response regression line.

RESULTS

Analysis of EOs revealed about 19 major components. All oils were found to be more repellent (ED50 range= 208-955μg cm-2) than DEET and permethrin (ED50 range= 27-182 × 103μg cm-2). Thyme and myrtle oils showed high repellent activities and among the total detected terpenes, thymol (36.26%) and α-pinene (32.5%) were the major components of those oils respectively.

CONCLUSION

Low repellent potency of DEET and permethrin against fleas might be related to flea olfactory system and further molecular and electrophysiological studies are required to conceive new ideas for the discovery and development of the next generation of repellents. Based on high repellent activity of thyme and myrtle essential oils against Pulex irritans further studies should be staged to develop their appropriate effective formulations. Likewise, field trials should be carried out to evaluate the operational feasibility and dermal toxicity over a long period.

Evaluation of the antidiarrheal activity of the leaf extracts of Myrtus communis Linn (Myrtaceae) in mice model

Background

Myrtus communis L. has a folkloric repute for the management of diarrhea and dysentery in different parts of the world. However, the safety and efficacy of the leaf extract have not been scientifically validated in animal model. This study was, therefore, aimed to investigate the antidiarrheal effect of 80% methanol extract (80ME) and solvent fractions of the leaves of Myrtus communis L. in mice.

Methods

The antidiarrheal activity of the 80ME and solvent fractions was evaluated against castor oil induced diarrheal model, charcoal meal and enteropooling tests. For the 80%ME, the test groups received 100, 200 and 400 mg/kg of the extract. In case of fractions, the test groups received various doses of fractions (200, 300, 400 mg/kg and an additional dose of 800 mg/kg for the aqueous fraction (AF)), where as negative controls received the vehicle (10 ml/kg) and positive controls received loperamide (3 mg/kg).

Results

The 80ME at 200 mg/kg (p < 0.05) & 400 mg/kg (p < 0.01) as well as the chloroform fraction (CF) and methanol fraction (MF) at 400 mg/kg (p < 0.05) significantly delayed the onset of diarrhea. Besides, the 80ME (at all tested doses) and both of these fractions (at 300 & 400 mg/kg) significantly decreased the frequency and weight of fecal outputs. Results from the charcoal meal test revealed that the 80ME, at all doses, (p < 0.001) as well as the CF and MF at 300 mg/kg (p < 0.05) & 400 mg/kg (p < 0.001) produced a significant anti-motility effect. Similarly, in the entero-pooling test, the 80ME (at all tested doses) (p < 0.01) as well as the CF and MF (at 300 & 400 mg/kg, p < 0.05) produced a significant decline in the weight and volume of intestinal contents, whereas the AF revealed significant effect (p < 0.05) at dose of 800 mg/kg only.

Conclusion

The study demonstrated that the 80ME and solvent fractions contain bioactive constituents that have antidiarrheal activity. Therefore, this study provides a scientific support for the acclaimed traditional use of Myrtus communis L for the treatment of diarrheal diseases.

A comparison of the efficacy of metronidazole vaginal gel and Myrtus (Myrtus communis) extract combination and metronidazole vaginal gel alone in the treatment of recurrent bacterial vaginosis

OBJECTIVE

Due to the high incidence of bacterial vaginosis (BV) and its resistance to chemical medications and considering the anti-bacterial and anti-fungal effects of Myrtus communis, the present study aimed to compare the therapeutic effects of the vaginal gel of M. communis 2% (in metronidazole base) with metronidazole vaginal gel 0.75% alone on BV.

MATERIALS AND METHODS

This research was a randomized controlled clinical trial conducted on 80 women of 18-40 years old with BV. Patients were divided into two groups of 40 women. Diagnostic criteria were Amsel's criteria and Gram staining. The first group received vaginal gel of metronidazole plus M. communis 2% and the second group received metronidazole vaginal gel alone for five consecutive nights. Therapeutic effects and Amsel's criteria were assessed after one week. Finally, the data were analyzed by SPSS 16 using t-test and Chi square tests.

RESULTS

There was a significant difference in the therapeutic response between the two groups. The results demonstrated that the combination of metronidazole and M. communis had a higher efficiency (p<0.05). The patients receiving M. communis in metronidazole gel base did not experience any recurrent BV, but 30% of patients taking metronidazole alone faced recurrent BV after three weeks of follow up.

CONCLUSION

Findings of the study suggested that adding M. communis extract to metronidazole increases the efficiency of BV treatment.

Myrtus communis L. and its application in treatment of Recurrent Aphthous Stomatitis

ETHNOPHARMACOLOGICAL RELEVANCE

In Iranian Traditional Medicine, M. communis is a famous plant in treatment of oral ulcers and "Gholaa"- the ancient name of aphthous.

OBJECTIVE

The aim of this review is to create a bridge between the traditional claims about the application of M. communis in treatment of "Gholaa" and its prescription for aphthous, the current form of "Gholaa" in modern medicine METHODS: We extracted the information about the application of M. communis in treatment of aphthous from different resources including Google scholar, Pubmed, ScienceDirect, Springer, ethnobotanical, the traditional books from Traditional Medicine Tehran University of Medical Sciences.

RESULTS

In Iranian traditional texts, "Gholaa" was the corrosive diseases on the surface and inner layer of mouth and tongue and divided into three types of bloody, phlegmatic and burned black bile types. Recurrent Aphthous Stomatitis (RAS) is equal to the black bile and phlegmatic types and minor aphthous type can be matched with phlegmatic type. The corrosive propagated lesions can be herpetic aphthous. In modern medicine, M. communis essential oil and its decoction decreased the average time of pain relief and decreased the size of ulcers in patients with minor RAS without any adverse effects. The number of ulcers was not the subjects of any different clinical trials. All patients were satisfied with M. communis topical essential oil (5%), and 81% patients were satisfied with M. communis topical decoctions (5%). It appears the efficacy of M. communis is related to its analgesic, anti-inflammatory, antiseptic and wound healing effects.

CONCLUSION

M. communis is effective in minor RAS as its traditional claims and confirming its efficacy in major and herpetiform RAS and comparing the efficacy of its decoction topical formulations or essential oil topical ones are required more and larger experimental and clinical investigations in future.

Profiling and Simultaneous Quantitative Determination of Anthocyanins in Wild Myrtus communis L. Berries from Different Geographical Areas in Sardinia and their Comparative Evaluation

INTRODUCTION

Myrtus communis L. (Myrtaceae) is a self-seeded shrub, widespread in Sardinia, with anti-inflammatory, antiseptic, antimicrobial, hypoglycemic and balsamic properties. Its berries, employed for the production of sweet myrtle liqueur, are characterised by a high content of bioactive polyphenols, mainly anthocyanins. Anthocyanin composition is quite specific for vegetables/fruits and can be used as a fingerprint to determine the authenticity, geographical origin and quality of raw materials, products and extracts.

OBJECTIVE

To rapidly analyse and determine anthocyanins in 17 samples of Myrtus communis berries by developing a platform based on the integration of UHPLC-MS/MS quantitative data and multivariate analysis with the aim of extracting the most information possible from the data.

METHODOLOGY

UHPLC-ESI-MS/MS methods, working in positive ion mode, were performed for the detection and determination of target compounds in multiple reaction monitoring (MRM) mode. Optimal chromatographic conditions were achieved using an XSelect HSS T3 column and a gradient elution with 0.1% formic acid in water and 0.1% formic acid in acetonitrile. Principal component analysis (PCA) was applied to the quantitative data to correlate and discriminate 17 geographical collections of Myrtus communis.

RESULTS

The developed quantitative method was reliable, sensitive and specific and was successfully applied to the quantification of 17 anthocyanins. Peonidin-3-O-glucoside was the most abundant compound in all the extracts investigated.

CONCLUSION

The developed methodology allows the identification of quali-quantitative differences among M. communis samples and thus defines the quality and value of this raw material for marketed products. Moreover, the reported data have an immediate commercial value due to the current interest in developing antioxidant nutraceuticals from Mediterranean plants, including Sardinian Myrtus communis. Copyright © 2016 John Wiley & Sons, Ltd.

Targeted and untargeted mass spectrometric approaches in discrimination between Myrtus communis cultivars from Sardinia region

In the present study, the discrimination of phytochemical content of Myrtus communis berries from different geographical origin and cultivars was explored by Liquid Chromatography-Electrospray Ionization-Fourier Transform-Mass Spectrometry (LC-ESI-FT-MS) metabolic profiling and quantitative analysis. Experiments were carried on myrtle plants grown in an experimental area of Sardinia region, obtained by the germination of seeds taken from berries collected in each part of the region. A preliminary untargeted approach on fruit's extracts was realized by collecting LC-ESI-FT-(Orbitrap)-MS data obtained by operating in negative ion mode and performing principal component analysis with the result of differentiation of samples. In a second step, targeted analysis with a reduced number of variables was realized. A data matrix was obtained by the data fusion of positive and negative ionization LC-ESI-MS results, by using as variables the peak areas of each known compounds. By the observation of principal component analysis, results found that anthocyanins, and mainly derivatives of cyanidin, are the principal marker compounds responsive for the discrimination of samples based on the geographical origin of the seeds. Based on this finding, finally, an LC-diode array detector method was developed, validated and applied for the quantitative analysis of berries' extracts based on 11 commercial standard compounds corresponding to the identified markers. Copyright © 2016 John Wiley & Sons, Ltd.

Antifungal and Herbicidal Effects of Fruit Essential Oils of Four Myrtus communis Genotypes

The chemical composition of the essential oils isolated by hydrodistillation from the fruits of four selected Myrtus communis L. genotypes from Turkey was characterized by GC-FID and GC/MS analyses. 1,8-Cineole (29.20-31.40%), linalool (15.67-19.13%), α-terpineol (8.40-18.43%), α-pinene (6.04-20.71%), and geranyl acetate (3.98-7.54%) were found to be the major constituents of the fruit essential oils of all M. communis genotypes investigated. The oils were characterized by high amounts of oxygenated monoterpenes, representing 73.02-83.83% of the total oil compositions. The results of the fungal growth inhibition assays showed that the oils inhibited the growth of 19 phytopathogenic fungi. However, their antifungal activity was generally lower than that of the commercial pesticide benomyl. The herbicidal effects of the oils on the seed germination and seedling growth of Amaranthus retroflexus L., Chenopodium album L., Cirsium arvense (L.) Scop., Lactuca serriola L., and Rumex crispus L. were also determined. The oils completely or partly inhibited the seed germinations and seedling growths of the plants. The findings of the present study suggest that the M. communis essential oils might have potential to be used as natural herbicides as well as fungicides.

Hypnotic effect of the essential oil from the leaves of Myrtus communis on mice

BACKGROUND

Myrtus communis has been suggested as a sleep aid in unconventional medicine. Moreover, previous studies have also indicated its sedative- and hypnotic-like activity. In this study, the hypnotic effect of M. communis was investigated.

METHODS

Essential oil (EO) of M. communis (600, 800, and 1,000 mg/kg) was given orally to Swiss albino mice of both sex, and the hypnotic effect was evaluated. In addition, the EO of M. communis (500, 600, 800, and 1,000 mg/kg) was administered orally to Swiss albino mice of both sex 60 minutes prior to pentobarbital injection (50 mg/kg). Latency to sleep and sleep duration were recorded. The effect of the EO on motor coordination and muscle relaxation was evaluated using chimney and traction tests, 60 and 90 minutes after administration of the respective doses of the EO, respectively.

RESULTS

There was no induction of hypnosis as the presence of the righting reflex was intact. However the EO prolonged pentobarbital-induced sleeping time and there was also 50% negative response on the chimney and traction test in a dose dependent manner.

CONCLUSION

The EO of M. communis did not produce a hypnotic effect, but it potentiated a hypnotic effect with significant central nervous system depressant activity.

Antidiarrhoeal, antimicrobial and antioxidant effects of myrtle berries (Myrtus communis L.) seeds extract

OBJECTIVES

The present study was carried out to determine the antidiarrheal effects of myrtle (Myrtus communis L.) berries seeds aqueous extract (MBSAE) from Tunisia as well as the involvement of its antimicrobial and antioxidant properties in such protection.

METHODS

Adult male wistar rats were used and divided into six groups of ten each: control, Castor oil, Castor oil + Loperamide and Castor oil + various doses of MBSAE. Animals were per orally (p.o.) pre-treated with MBSAE for one hour and intoxicated by castor oil acute oral administration.

KEY FINDINGS

Our results demonstrated that the MBSAE is rich in total and condensed tannins and exhibited a broad spectrum of antibacterial activity. In vivo, we found that MBSAE administration induced a significant dose-dependent protection against diarrhoea and intestinal fluid accumulation. Castor oil-induced intestinal hypersecretion was accompanied by an oxidative stress status in the intestine. More importantly, we showed that acute diarrhoea was accompanied by an increase in intestinal mucosa hydrogen peroxide (H2 O2 ), calcium and free iron levels while MBSAE pre-treatment reversed all castor oil-induced intracellular mediators disturbances.

CONCLUSIONS

We suggest that MBSAE had a potent protective effects against castor oil-induced acute diarrhoea due in part to its antioxidant and antimicrobial properties.

In vitro and in vivo antidermatophytic activities of some Iranian medicinal plants

In the last decades, the number of people suffering from dermatophytoses has seriously increased, which may be due to the development of resistant strains to a range of antifungal drugs. The present study was aimed to evaluate the antidermatophytic properties of eight extracts from the selected spices and herbs, which were ethno-medicinally used in Iran against Trichophyton mentagrophytes, Trichophyton interdigitale, Microsporum canis, and Microsporum gypseum (10 strain of each). The in vitro antifungal activities of the extracts from four spices and four plants were evaluated by the broth macro dilution method against four dermatophyte strains. In addition, the in vivo therapeutic effects of Myrtus communis L. and Cinnamomum zeylanicum Blume extracts (the most active extracts) on dermatophytosis induced by M. canis and T. mentagrophytes in guinea pigs were evaluated. Results of in vitro antifungal assay revealed that all the tested extracts demonstrated both fungistatic and fungicidal activities with the geometric mean (GM) MIC ranging from 0.058 to 3.73 mg/ml and GM (MFC) ranging from 0.058 to 7.46 mg/ml, respectively. Two extracts (M. communis and C. zeylanicum) significantly inhibited the growth of all the tested dermatophytes, while other extracts demonstrated weak (MICs of >0.625 mg/ml) to moderate (MICs ranging from 100 to 0.625 mg/ml) activities. In vivo antidermatophytic assay demonstrated that clotrimazole cured T. mentagrophytes and M. canis infection on days 21 and 17, respectively, whereas M. communis and C. zeylanicum extracts significantly (p < 0.05) cured T. mentagrophytes and M. canis infection on days 9 and 13 as well as 9, 11, respectively. Phytochemical screening showed the presence of flavonoids, tannins, phenols, and alkaloids in M. communis and alkaloids, flavonoids, and tannins in C. zeylanicum. Findings of the present study also provided the scientific evidence that natural plants could be used in traditional medicine for the prevention and treatment of dermatophytic infections.

Myrtus communis L. as source of a bioactive and safe essential oil

In Algeria, Myrtus communis L. is distributed throughout the Tell Atlas and the coastal regions of Algiers and Constantine. The leaves are used in respiratory disorders, diarrhea and hemorrhoids. The aims of this work were to evaluate the antifungal and anti-inflammatory potential of well characterized essential oils (EO). Since EO can be applied by inhalation, dermal application and oral administration, we used several mammalian cell lines to assess safe bioactive doses. The chemical composition of two samples was investigated by GC-FID, GC-MS and (13)C NMR spectroscopy. Monoterpene derivatives are the main compounds: α-pinene (50.8 and 33.6%), 1,8-cineole (21.9 and 13.3%), linalool (2.7 and 14.8%), and linalyl acetate (0.5 and 9.5%). The antifungal evaluation revealed that the oils were more active against Cryptococcus neoformans (yeast) and Epidermophyton floccosum, Microsporum canis, Trichophyton rubrum (dermatophytes). The anti-inflammatory potential was evaluated using an in vitro model of lipopolysaccharide (LPS)-stimulated macrophages. Assessment of cell viability was made through the MTT assay. Both oils were able to significantly inhibit NO production, without affecting cell viability, in concentrations up to 0.64 mg/mL. These promising results, disclose bioactive concentrations of Myrtle essential oils with a safety profile suggesting a potential oral and topical application or use by inhalation.

Chemical constituent and antimicrobial effect of essential oil from Myrtus communis leaves on microorganisms involved in persistent endodontic infection compared to two common endodontic irrigants: An in vitro study

INTRODUCTION

Persistent infections of human root canals play a fundamental role in the failure of endodontic treatment. The purpose of this study is to determine the chemical composition of Myrtus communis (M. communis) essential oil and to assess its antimicrobial activity against Enterococcus faecalis, Staphylococcus aureus and Candida albicans compared to that of sodium hypochlorite (NaOCl) and chlorhexidine (CHX).

MATERIALS AND METHODS

Gas chromatography-mass spectrometry (GC-MS) was used to determine the chemical composition of essential oil from M. communis leaves. A micro-dilution susceptibility assay and disk diffusion methods were utilized to evaluate the antimicrobial activity [minimum inhibitory concentration (MIC) and minimum lethal dose concentration] of the tested solutions against selected microorganisms.

RESULTS

GC-MS analyses revealed that M. communis contained 1, 8-Cineole (28.62%), α-Pinene (17.8%), Linalool (17.55%), and Geranylacetate (6.3%) as the major compounds and Geraniol (1.6%), α-Humulene (1.5%), eugenol (1.3%), isobutyl-isobutyrate (0.8%), and methyl chavicol (0.5%) as minor components. Chlorhexidine had the lowest MIC value among all medicaments tested. M. communis oil had less MIC values than NaOCl against both bacteria, but it had more MIC value against C. albicans.

CONCLUSION

M. communis essential oil with the minimum inhibitory concentration in the range of 0.032-32 μg/mL was an effective antimicrobial agent against persistent endodontic microorganisms.

Studies with Myrtus communis L.: Anticancer properties

Myrtus communis (MC) L. is a well-known Mediterranean plant with important cultural significance in this region. In ancient times, MC was accepted as a symbol of immortality. Maybe due to this belief, it is used during cemetery visits in some regions. Although it is a well-known plant in cosmetics, and there is a lot of studies about its different medical properties, anticancer studies performed using its different extracts or oils are not so much, but increasing. We collected these anticancer property-related studies in this review.

Antioxidative properties and ability of phenolic compounds of Myrtus communis leaves to counteract in vitro LDL and phospholipid aqueous dispersion oxidation

Antioxidant activities of Myrtus communis leaf phenolic compounds (McPCs) were investigated on 2,2'-9-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS(+) •) and oxygen radical absorbance capacity (ORAC) tests or on oxidation of biological models, human low-density lipoprotein (LDL) and phospholipid aqueous dispersion (L-α-phosphatidylcholine stabilized by bile salts). Two extraction techniques, microwave-assisted (MAE) and conventional (CE), were used to isolate McPCs, producing similar results of phenolic compound content. ABTS(+) • assay showed clearly that myrtle extracts exhibited a stronger scavenging effect than butylated hydroxyanisole and α-tocopherol, with a slight advantage for myrtle CE extract. In ORAC assay, the both McPC extracts were similarly less effective than the pure compounds as caffeic acid and myricitrin (myricetin 3-O-rhamnoside) but stronger than butylated hydroxytoluene. Moreover, myrtle CE and MAE extracts, and myricitrin were able to inhibit similarly the production of conjugated dienes and to prolong the lag phase (Tlag) during Cu(2+)-induced LDL oxidation with a dose-response effect. The cryo-electron microscopy observations on studied phospholipid dispersion stabilized by bile salts (BS) revealed the presence of bilayer vesicles and micelles. In 2,2'-azobis (2-amidinopropane) hydrochloride-induced phospholipid/BS oxidation, myrtle CE and MAE extracts gave similar effects to α-tocopherol and caffeic acid but myricitrin showed a higher protective effect than myrtle extracts. We showed also that no synergic or additive effect between α-tocopherol and myrtle extracts or caffeic acid in α-tocopherol-enriched phospholipid/BS dispersion, but myricitrin showed an additive effect and thus promoted the total antioxidant activity. These data showed that myrtle extract could be used as potential natural antioxidants, food stabilizers, or natural health products.

PRACTICAL APPLICATION

We show that microwave-assisted extraction could be an alternative method for plant phenolic compound recovery allowing important gain in time extraction.We report inhibition of low-density lipoprotein oxidation in vitro initiated by Cu(2+) ions. We report that myrtle extract may be a source of natural antioxidants to counteract phospholipid peroxidation as well as α-tocopherol.

The effect of oleum myrtle on the fruit quality of strawberries during MAP storage

Strawberries are known to be significant source of the nutraceuticals; however, rapid perishable property of this fruit is very important issue. Up to now, extension of this fruit is still the focus of scientific and industrial interest in the worldwide. Therefore, of the known nutraceuticals, myrtle essential oil in this study is intended to use for extending the storage of strawberries. Strawberries were individually immersed in the treatment solutions of 0.1 % myrtle oil, 0.5 % myrtle oil and then placed in Modified Atmosphere Packaging (MAP) for 8 days at 5 °C. The control fruits without myrtle oil treatment were also placed in MAP and stored under the same condition. Treatment of myrtle oil decreased the weight and the fruit firmness loss. Furthermore, titratable acidity (TA), pH and colour value did not display significant changes during storage. Fluctuations were observed in the vitamin C, total soluble solids (TSS), TSS/TA content and microbial growth. The O2 concentration in MAP decreased from 21 % to around 15 %, whereas, CO2 concentration varied from 6.0 to 6.9 % in the treatments by the 8th day of storage time. The delay of flesh firmness, weight loss, vitamin C loss and increasing CO2 concentration in MAP, best sensory quality as well as limiting the growth of microbial parameters in concern was attained through the use of 0.5 % myrtle oil, suggesting that 0.5 % myrtle oil showed more pronounced activity than 0.1 % myrtle oil and control in maintaining the fruit quality and shelf life of fruits during MAP storage.

Review of pharmacological effects of Myrtus communis L. and its active constituents

Myrtle (Myrtus communis L., Myrtaceae) is a medicinal herb used worldwide in traditional medicine. A large number of components have been isolated from this herb. Polyphenols, myrtucommulone (MC), semimyrtucommulone (S-MC), 1,8-cineole, α-pinene, myrtenyl acetate, limonene, linalool and α-terpinolene are among the compounds considered to be the main biologically active components. Various parts of this herb such as its berries, leaves and fruits have been used extensively as a folk medicine for several centuries. The herb is used traditionally for the treatment of disorders such as diarrhea, peptic ulcer, hemorrhoid, inflammation, pulmonary and skin diseases, although clinical and experimental studies suggest that it possesses a broader spectrum of pharmacological and therapeutic effects such as antioxidative, anticancer, anti-diabetic, antiviral, antibacterial, antifungal, hepatoprotective and neuroprotective activity. The present review attempts to give an overview on the phytochemical, pharmacological, toxicological and clinical studies of total extracts and the most relevant active ingredients of M. communis.

Morphological, anatomical and physiological leaf traits of Q. ilex, P. latifolia, P. lentiscus, and M. communis and their response to Mediterranean climate stress factors

BACKGROUND

Limitations to plant growth imposed by the Mediterranean climate are mainly due to carbon balance in response to stress factors. In particular, water stress associated to high air temperature and irradiance in summer causes a marked decrease in CO2 assimilation. Air temperature sensitivity of photosynthesis (PN) differs from that of leaf respiration (RD). PN often decreases sharply at temperature above its optimum while RD increases exponentially over short term rises in temperature. Nevertheless, the impact of water deficit on RD is still far from clear with reports in literature including decreases, maintenance or increases in its rates. The ratio RD/PN can be considered a simple approach to leaf carbon balance because it indicates the percentage of photosynthates that is respired.

RESULTS

The results underline different morphological, anatomical and physiological traits of the evergreen species co-occurring in the Mediterranean maquis which are indicative of their adaptive capability to Mediterranean stress factors. The ratio RD/PN varies from 0.15 ± 0.04 in autumn, 0.24 ± 0.05 in spring through 0.29 ± 0.15 in winter to 0.46 ± 0.11 in summer. The lower RD/PN in autumn and spring underlines the highest PN rates during the favorable periods when resources are not limited and leaves take in roughly three to five times more CO2 than they lose by respiration. On the contrary, the highest RD/PN ratio in summer underlines the lowest sensitivity of respiration to drought. Among the considered species, Quercus ilex and Pistacia lentiscus have the largest tolerance to low winter temperatures while Phillyrea latifolia and Myrtus communis to drought, and Phillyrea latifolia the highest recovery capability after the first rainfall following drought.

CONCLUSIONS

The Mediterranean evergreen specie shows a different tolerance to Mediterranean climate stress factors. The predicted global warming might differently affect carbon balance of the considered species, with a possible change in Mediterranean shrublands composition in the long-term. Understanding the carbon balance of plants in water limited environments is crucial in order to make informed land management decisions. Moreover, our results underline the importance of including seasonal variations of photosynthesis and respiration in carbon balance models.

The Myrtle rust pathogen, Puccinia psidii, discovered in Africa

Puccinia psidii, the cause of a disease today commonly referred to as Myrtle rust, is considered a high priority quarantine threat globally. It has a wide host range in the Myrtaceae and it is feared that it may result in significant damage to native ecosystems where these plants occur. The fungus is also of considerable concern to plantation forestry industries that propagate Australian Eucalyptus species. In May 2013, symptoms of a rust disease resembling those of P. psidii were observed on an ornamental Myrtaceous shrub in a garden in South Africa. The fungus was identified based on DNA sequence data of the ITS and 5.8S nrRNA gene regions and here we report, for the first time, the presence of P. psidii in Africa.

Effect of maturation and cold storage on the organic acid composition of myrtle fruits

BACKGROUND

The effect of maturation and senescence on the chemical composition of two myrtle cultivars was studied in mature, overripe and cold-stored fruits in order to find the most appropriate harvesting period and best storage technology for industrial purposes.

RESULTS

After cold storage at 10 °C for 15 days, berry weight loss ranged from 12.5 to 18.4%, with the highest losses in less mature fruits. Titratable acidity decreased during maturation and cold storage in both cultivars. Reducing and total sugars increased during maturation. Anthocyanin concentration increased during maturation but decreased in overripe berries. The major organic acids in myrtle fruits were quinic, malic and gluconic acids. In fresh and cold-stored fruits, malic acid rose to 3 g kg(-1) and decreased thereafter. Quinic acid peaked at 90 or 120 days after bloom and decreased thereafter to reach low concentrations in mature fruits.

CONCLUSION

Cold storage for 15 days at 10 °C does not affect myrtle fruit quality for liqueur production. Anthocyanin concentration is the best indicator of harvest time for industrial purposes. Gluconic acid concentration is high in mature, overripe and cold-stored berries. This parameter can be used as a marker of the onset of fruit senescence.

Repellency Effects of Essential Oils of Myrtle (Myrtus communis), Marigold (Calendula officinalis) Compared with DEET against Anopheles stephensi on Human Volunteers

BACKGROUND

Malaria and leishmaniasis are two most significant parasitic diseases which are endemic in Iran. Over the past decades, interest in botanical repellents has increased as a result of safety to human. The comparative efficacy of essential oils of two native plants, myrtle (Myrtus communis) and marigold (Calendula officinalis) collected from natural habitats at southern Iran was compared with DEET as synthetic repellent against Anopheles stephensi on human subjects under laboratory condition.

METHODS

Essential oils from two species of native plants were obtained by Clevenger-type water distillation. The protection time of DEET, marigold and myrtle was assessed on human subject using screened cage method against An. stephensi. The effective dose of 50% essential oils of two latter species and DEET were determined by modified ASTM method. ED(50) and ED(90) values and related statistical parameters were calculated by probit analysis.

RESULTS

The protection time of 50% essential oils of marigold and myrtle were respectively 2.15 and 4.36 hours compared to 6.23 hours for DEET 25%. The median effective dose (ED(50)) of 50% essential oils was 0.1105 and 0.6034 mg/cm(2) respectively in myrtle and marigold. The figure for DEET was 0.0023 mg/cm(2).

CONCLUSION

This study exhibited that the repellency of both botanical repellents was generally lower than DEET as a synthetic repellent. However the 50% essential oil of myrtle showed a moderate repellency effects compared to marigold against An. stephensi.