Anti-hyperglycaemic effect of an extract of Myrtus communis in streptozotocin-induced diabetes in mice

The therapeutic value of Myrtus communis L.: an updated review

Myrtus communis L. (Family: Myrtaceae) is naturally found in the western part of Asia, Southern Europe, and North Africa. It has been reportedly applied in pharmaceutical industry, traditional medicine, cosmetics, spices, and food. Pubmed, Google scholar, Web of Science, and Scopus were utilized to seek out relevant content concerning the therapeutic potential of M. communis. Subsequently, we conducted a review to identity noteworthy updates pertaining to M. communis. Myrtle berries, leaves, seeds, and essential oils are natural sources of several nutrients and bioactive compounds with marked health effects. The chemical analysis showed that M. communis contained oils, alkaloids, flavonoids, phenolics, coumarins, saponosides, tannins, quinines, and anthraquinones. A pharmacological investigation revealed that M. communis possessed anti-inflammatory, analgesic, antimicrobial, antiparasitic, antioxidant, antidiabetic, anticancer, antimutagenic, immunomodulatory, dermatological, cardiovascular, central nervous system, and gastrointestinal protective effects, among numerous other biological effects. This current review focused on the biochemical, pharmacological, therapeutic effects, and various biological activities of different parts of M. communis. It signifies that M. communis is a therapeutic plant with numerous applications in medicine and could be used as a drug isolate based on its safety and effectiveness.

Histological and biochemical effects of an ethanolic extract of Myrtus communis leaf on the pancreases of rats fed high fat diets

We investigated the effects of an ethanolic extract of Myrtus communis subsp. communis (MC) leaves on the pancreases of rats fed with a high fat diet (HFD). Wistar albino rats were fed either with standard lab chow (Control group) or with a 45% fat diet (HFD and HFD+MC groups) for 4 months, with the MC extract (100 mg/kg) being administered by orogastric gavage to rats in the HFD+MC group during the last month. Blood and pancreas samples were collected from all experimental groups at the end of the study. Insulin and leptin levels, and the lipid profile, were analyzed in the blood serum. Pancreatic injury was assessed histologically. Insulin, nuclear factor kappa beta (NF-κB), and alpha-smooth muscle actin (α-SMA) were assessed using immunohistochemistry. Apoptosis was assessed using terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) immunohistochemistry. In addition, oxidant/antioxidant activity was analyzed by biochemical methods. Increased body weight, serum insulin and leptin levels, blood glucose level and pancreatic tissue malondialdehyde (MDA), 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, myeloperoxidase (MPO) activity and decreased tissue glutathione (GSH) level were observed in the HFD group compared to the Control group, in addition to dyslipidemia. An increased histopathological damage score, pancreatic islet area, insulin, TUNEL, NF-κB and α-SMA immunoreactivity were seen in animals from the HFD group compared to the Control group. However, such pathological changes were reduced in the HFD+MC group. Our data indicate further investigation of MC extract as a therapeutic adjuvant for HFD-induced pancreatic injury, acting via anti-inflammatory and antioxidant mechanisms, is worth carrying out.

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.

Natural Compounds and PCL Nanofibers: A Novel Tool to Counteract Stem Cell Senescence

Tissue homeostasis mainly depends on the activity of stem cells to replace damaged elements and restore tissue functions. Within this context, mesenchymal stem cells and fibroblasts are essential for maintaining tissue homeostasis in skin, in particular in the dermis. Modifications in collagen fibers are able to affect stem cell features. Skin properties can be significantly reduced after injuries or with aging, and stem cell niches, mainly comprising extracellular matrix (ECM), may be compromised. To this end, specific molecules can be administrated to prevent the aging process induced by UV exposure in the attempt to maintain a youngness phenotype. NanoPCL-M is a novel nanodevice able to control delivery of Mediterranean plant myrtle (Myrtus communis L.) extracts. In particular, we previously described that myrtle extracts, rich in bioactive molecules and nutraceuticals, were able to counteract senescence in adipose derived stem cells. In this study, we analyzed the effect of NanoPCL-M on skin stem cells (SSCs) and dermal fibroblasts in a dynamic cell culture model in order to prevent the effects of UV-induced senescence on proliferation and collagen depot. The BrdU assay results highlight the significantly positive effect of NanoPCL-M on the proliferation of both fibroblasts and SSCs. Our results demonstrate that-M is able to preserve SSCs features and collagen depot after UV-induced senescence, suggesting their capability to retain a young phenotype.

Smart Nanofibers with Natural Extracts Prevent Senescence Patterning in a Dynamic Cell Culture Model of Human Skin

Natural cosmetic products have recently re-emerged as a novel tool able to counteract skin aging and skin related damages. In addition, recently achieved progress in nanomedicine opens a novel approach yielding from combination of modern nanotechnology with traditional treatment for innovative pharmacotherapeutics. In the present study, we investigated the antiaging effect of a pretreatment with Myrtus communis natural extract combined with a polycaprolactone nanofibrous scaffold (NanoPCL-M) on skin cell populations exposed to UV. We set up a novel model of skin on a bioreactor mimicking a crosstalk between keratinocytes, stem cells and fibroblasts, as in skin. Beta-galactosidase assay, indicating the amount of senescent cells, and viability assay, revealed that fibroblasts and stem cells pretreated with NanoPCL-M and then exposed to UV are superimposable to control cells, untreated and unexposed to UV damage. On the other hand, cells only exposed to UV stress, without NanoPCL-M pretreatment, exhibited a significantly higher yield of senescent elements. Keratinocyte-based 3D structures appeared disjointed after UV-stress, as compared to NanoPCL-M pretreated samples. Gene expression analysis performed on different senescence associated genes, revealed the activation of a molecular program of rejuvenation in stem cells pretreated with NanoPCL-M and then exposed to UV. Altogether, our results highlight a future translational application of NanoPCL-M to prevent skin aging.

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.

Antioxidant Activity of Myrtus communis L. and Myrtus nivellei Batt. & Trab. Extracts: A Brief Review

Myrtus communis L. (myrtle) and Myrtus nivellei Batt. & Trab. (Saharan myrtle) have been used in folk medicine for alleviating some ailments. M. communis is largely distributed in the Mediterranean Basin, whereas M. nivellei is confined in specific zones of the central Saharan mountains. The chemical composition and antioxidant activity of berry and leaf extracts isolated from myrtle are deeply documented, whereas those isolated from Saharan myrtle extracts are less studied. In both species, the major groups of constituents include gallic acid derivatives, flavonols, flavonol derivatives, and hydroxybenzoic acids. In coloured berries, anthocyanins are also present. In M. nivellei extracts are reported for some compounds not described in M. communis so far: 2-hydroxy-1,8-cineole-β-d-glucopyranoside, 2-hydroxy-1,8-cineole 2-O-α-l-arabinofuranosyl (1→6)-β-d-glucopyranoside, rugosin A, and rugosin B. Berries and leaves extracts of both species had antioxidant activity. Comparative studies of the antioxidant activity between leaf and berry myrtle extracts revealed that leaf extracts are best antioxidants, which can be assigned to the galloyl derivatives, flavonols, and flavonols derivatives, although the ratio of these groups of compounds might also have an important role in the antioxidant activity. The anthocyanins present in myrtle berries seem to possess weak antioxidant activity. The antioxidant activity of sample extracts depended on various factors: harvesting time, storage, extraction solvent, extraction type, and plant part used, among other factors. Leaf extracts of myrtle revealed to possess anti-inflammatory activity in several models used. This property has been attributed either to the flavonoids and/or hydrolysable tannins, nevertheless nonprenylated acylphloroglucinols (e.g., myrtucommulone and semimyrtucommulone) have also revealed a remarkable role in that activity. The biological activities of myrtle extracts found so far may direct its use towards for stabilizing complex lipid systems, as prebiotic in food formulations, and as novel therapeutic for the management of inflammation.

A Mechanistic Review on Medicinal Plants Used for Diabetes Mellitus in Traditional Persian Medicine

Diabetes mellitus is the most common endocrine disorder and a major cause of morbidity and mortality. Traditional medicines worldwide suggest a wide range of natural remedies for the prevention and treatment of chronic disorders, including diabetes mellitus. This mechanistic review aims to highlight the significance of medicinal plants traditionally used as dietary supplements in Persian medicine in adjunct with restricted conventional drugs for the prevention and treatment of diabetes mellitus. Mounting evidence suggests that these natural agents perform their protective and therapeutic effect on diabetes mellitus via several cellular mechanisms, including regeneration of pancreatic β cell, limitation of glycogen degradation and gluconeogenesis, anti-inflammatory, immunoregulatory, antiapoptosis, antioxidative stress, as well as modulation of intracellular signaling transduction pathways. In conclusion, traditional medicinal plants used in Persian medicine can be considered as dietary supplements with therapeutic potential for diabetes mellitus and maybe potential sources of new orally active agent(s).

Ethnobotanical, Ethnopharmacological, and Phytochemical Studies of Myrtus communis Linn: A Popular Herb in Unani System of Medicine

Myrtus communis L (Myrtaceae) is one of the popular drugs being used in the Unani system of phytomedicine since ancient Greece period. From time immemorial, different parts of this plant and essential oil have been used for a variety of purposes such as cosmetics (hair fall control), flavoring of food and drinks as well as extensive therapeutic purposes. Ethnobotanical information revealed that M communis L has been a folkloric repute for the treatment of several diseases like gastric ulcer, diarrhea, dysentery, cancer, rheumatism, hemorrhage, deep sinuses, leucorrhoea, hemorrhoid, inflammation, dyspepsia, anxiety, insomnia, diabetes, hypertension, pulmonary disorders, and skin diseases. Moreover, ethnopharmacological studies revealed that the plant is endowed with extensive pharmacological activities, including antimicrobial, antidiarrheal, antidiabetic, antispasmodic, vasodilator, antiulcer, antioxidant, anticancer, anxiolytic, sedative-hypnotic, and anti-inflammatory activities, among others. The plant has been known to contain phenolic acids, tannins, flavonoids, glycosides, and terpenes. The myrtle oil was also found to be rich in a variety of bioactive monoterpenes and sesquiterpenes with their derivatives. Most of these studies validate the aforementioned traditional claims of this medicinal plant. Further studies are needed to unravel other pharmacological activities of this plant in the long run.

Natural Therapeutic Options in Endodontics - A Review

Complete eradication of microbial biofilms and elimination of the smear layer are the key factors during endodontic treatment. Various chemical irrigants have been proposed in the literature for the same. The major setback with these chemical irrigants is that they are not bio-friendly to the dental and peri-radicular tissues. In the recent years, research to use natural products for root canal disinfection has gained importance. The aim of this article is to compile various herbal products that have been used as an irrigants and intracanal medicaments in the field of Endodontics to eradicate the biofilm and remove smear layer.

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.

Myrtucommulone-A Induces both Extrinsic and Intrinsic Apoptotic Pathways in Cancer Cells

Myrtucommulone-A is the active compound derived from Myrtus communis. The molecular targets of myrtucommulone-A is widely unknown, which impedes its potential therapeutic use. In this study, we demonstrated the cytotoxicity of MC-A and its potential to induce apoptosis in cancer cells. Myrtucommulone-A was also found to be antiproliferative and strongly inhibited cancer cell migration. Eighty four apoptotic pathway genes were used to assess the effect of myrtucommulone-A on cancer cells. Myrtucommulone-A mediated an increase in apoptotic genes including Fas, FasL, Gadd45a, Tnf, Tnfsf12, Trp53, and caspase 4. The increase in myrtucommulone-A dose (25 μM versus 6.25 μM) also upregulated the expression of genes, which are involved mainly in apoptosis, regulation of apoptosis, role of mitochondria in apoptotic signaling, cytokine activity, and tumor necrosis factor signaling. Our data indicate that myrtucommulone-A could be utilized as a potential therapeutic compound with its molecular targets in apoptotic pathways.

Antibacterial activity of the essential oils of myrtle leaves against Erysipelothrix rhusiopathiae

OBJECTIVE

To evaluate the antibacterial activity of the essential oil of Myrtus communis (M. communis) L. against Erysipelothrix rhusiopathiae (E. rhusiopathiae) in vitro.

METHODS

Wild populations of M. communis collected from Khuzestan and Lorestan provinces, Southwest Iran, were examined for antibacterial activity and chemical variability in leaves. The in vitro antibacterial activity against E. rhusiopathiae was performed by agar disc diffusion and micro-dilution assays.

RESULTS

The essential oils of M. communis have strong antibacterial against E. rhusiopathiae in both assays. The results showed that the major components of the oil were α-pinene (22.3%-55.2%), 1,8-cineole (8.7%-43.8%) and linalool (6.4%-14.5%). The inhibition zones and MIC values for bacteria which were sensitive to the essential oils of M. communis were in the range of 14.7-27.0 mm and 0.031-0.25 mg/mL, respectively.

CONCLUSIONS

This study demonstrates that products with valuable antibacterial activity can be produced from leaves of M. communis against E. rhusiopathiae.

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.

Therapeutic potential of some plant extracts used in Turkish traditional medicine on streptozocin-induced type 1 diabetes mellitus in rats

Diabetes mellitus (DM) is known to impair many physiological functions. Some reports claim that medicinal plants can reduce these alterations caused by DM. The aim of this study was to investigate the therapeutic potential of aqueous-methanol extracts of Urtica dioica, Thymus vulgaris (TV), Myrtus communis (MC), Scolymus hispanicus (SH) and Cinnamomun zeylanicum (CZ) on streptozotocin (STZ)-induced type 1 DM in rats. Diabetes was induced via a single i.p. injection of STZ (65 mg/kg body weight). After 1 week to allow for development of diabetes, each plant extract was administered to diabetic rats separately at a dose of 100 mg/kg body weight daily for 28 days. The results showed that only SH extract significantly (P < 0.05) amended fasting blood glucose level. The lipid profile was ameliorated especially by supplementations of TV, MC and CZ extracts. Almost all plant extract treatments markedly (P < 0.05) increased reduced glutathione content and decreased lipid peroxidation levels of erythrocyte, plasma, retina and lens tissues. They also significantly (P < 0.05) amended erythrocyte catalase activity, levels of marker serum enzymes (except amylase), urea and blood urea nitrogen when compared to diabetic rats treated with nothing. Furthermore, none of the plant extracts counteracted body weight loss of diabetic rats. Our data revealed that the aforementioned plant extracts have remarkable potential to counteract DM-caused alterations, probably through their antioxidant and free radical-defusing effects.

Antinociceptive, anti-inflammatory effects and acute toxicity of aqueous and ethanolic extracts of Myrtus communis L. Aerial parts in mice

Myrtus communis L. aerial parts have been used in traditional medicine for the treatment of inflammatory disease. In this study 350 mice were divided into three main groups: negative (saline), positive (morphine or diclofenac) controls, and test groups. The acute toxicity was assessed for 2 days. Antinociceptive activity was performed using hot plate and writhing tests. The anti-inflammatory effect was investigated using xylene-induced ear edema and a cotton pellet test. According to phytochemical screening, the extracts contained tannins, alkaloids, and flavonoids. The LD50 values of the aqueous and ethanolic extracts were 0.473 and 0.79 g/kg, respectively. In hot plate test, the aqueous and ethanolic extracts showed significant antinociceptive activity that was inhibited by naloxone. The extracts exhibited antinociceptive activity against acetic acid-induced writhing and also showed significant activity against acute inflammation which was dose dependent for aqueous extract. The ethanolic (0.05 g/kg) and aqueous extracts (0.005, 0.015, and 0.03 g/kg) demonstrated anti-inflammatory effects against chronic inflammation. The aqueous and ethanolic extracts of the aerial parts of M communis L. showed antinociceptive effects and these may be mediated by opioid receptors.

Essential Oil of Myrtus communis Inhibits Inflammation in Rats by Reducing Serum IL-6 and TNF-α

The topical anti-inflammatory activity of the essential oil of Myrtus communis L. was studied using croton oil induced ear edema and myeloperoxidase (MPO) activity in mice, and cotton pellet induced granuloma, and serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in rats. On topical application, the oil exhibited a significant decrease in the ear edema as well as MPO activity. The oil also inhibited cotton pellet-induced granuloma and serum TNF-α and IL-6. It can be concluded that the essential oil of Myrtus communis reduces leukocyte migration to the damaged tissue and exhibits anti-inflammatory activity.

Composition and Chemical Variability of Leaf Oil of Myrtus Communis from North-Eastern Algeria

The chemical composition of 27 oil samples of Myrtus communis isolated from leaves collected in three locations in north–eastern Algeria was investigated by GC(RI) and 13C NMR spectroscopy. Yields ranged between 0.2-1.2% (w/w). The chemical composition of the oils was largely dominated by monoterpene hydrocarbons, with α-pinene (40.5-64.0%), 1,8-cineole (10.9-29.1%) and limonene (6.7-8.2%) being the major compounds. In all the samples, 3,3,5,5,8,8-hexamethyl-7-oxabicyclo[4.3.0]non-1(6)-ene-2,4-dione was identified (0.8-1.5%). The composition is similar to that reported for myrtle oils from Corsica, Sardinia and Tunisia, but differed from that of Moroccan and Spanish myrtle oils.

In vitro synergistic efficacy of combination of amphotericin B with Myrtus communis essential oil against clinical isolates of Candida albicans

In this study, we evaluated the antifungal activity of the essential oil from Myrtus communis (myrtle) leaves against Candida albicans (eight clinical isolates and one ATCC type strains) and different species of Aspergillus sp (A. niger, A. parasiticus, six isolates of Aspergillus flavus) using broth micro dilution assay. In addition, we evaluated the synergistic effect between the essential oil and the antifungal compound amphotericin B by checkboard micro titer assay. The essential oil was obtained from myrtle leaves by hydrodistillation method and the oil was analyzed by GC and GC-MS methods. Chemical analysis of oil revealed the presence of 70 components, representing 99.23% of the total oil. 1,8-cineole (36.1%), alpha-pinene (22.5%), linalool (8.4%), bornyl acetate (5.2%), alpha-terpineol (4.4%), linalyl acetate (4.2%) and limonene (3.8%) were found to be the major components of the oil. The antifungal evaluating showed that myrtle oil exhibited good antifungal activity against fungi. Myrtle oil showed significant antifungal activity when combined with amphotericin B.

Essential oil of Myrtus communis L. as a potential antioxidant and antimutagenic agents

The present study describes DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and antimutagenic properties of the essential oil of myrtle (Myrtus communis L.). Plant samples were collected from the two distant localities (southernmost and northern point) of the Montenegro coastline. Chemical profiles of the two samples were evaluated by GC-MS. In both of the samples monoterpenes were found to be the predominant compounds. Among them α-pinene, linalool, 1,8-cineole, and myrtenyl acetate were the major compounds. Significant differences between the samples were found in the ranges of α-pinene (14.7%–35.9%) and myrtenyl acetate (5.4%–21.6%). Both oils exhibited moderate DPPH scavenging activity, with IC₅₀ values of 6.24 mg/mL and 5.99 mg/mL. The antimutagenic properties were assayed against spontaneous and t-BOOH-induced mutagenesis in Escherichia coli oxyR mutant IC202, a bacterial strain deficient in removing ROS. Reduction of the spontaneous mutagenesis in presence of myrtle EO was only slight, up to 13% at the highest concentration tested. When the oxidative mutagen was used, EO expressed higher reduction of mutagenesis, in a concentration dependent manner, with statistical significance for effect at the highest concentration tested (28%). Suppression of t-BOOH induced mutagenesis was correlated with the observed scavenging activity.

Antioxidant activities of the essential oils and methanol extracts from myrtle (Myrtus communis var. italica L.) leaf, stem and flower

This study was designed to examine the chemical composition and antioxidant activity of the essential oils and methanol extracts of Myrtus communis var. italica L. leaf, stem and flower. Myrtle leaf and flower were the valuable organs for the essential oil production representing a yield of 0.61% and 0.30% (w/w), respectively. The essential oil composition of myrtle leaf and flower was characterized by high proportions of alpha-pinene, the main compound of monoterpene hydrocarbon class, with 58.05% for leaf and 17.53% for flower. Stem was rich in oxygenated monoterpenes, largely due to 1,8-cineole with 32.84%. The total phenol contents varied between different myrtle parts; leaf extract had higher total phenol content (33.67 mg GAE/g) than flower (15.70 mg GAE/g) and stem (11.11 mg GAE/g) extracts. Significant differences were also found in total tannin contents among different myrtle parts, representing 26.55 mg GAE/g in leaf, 11.95 mg GAE/g in flower, 3.33 mg GAE/g in stem. The highest contents of total flavonoids and condensed tannins were observed in stem (5.17 and 1.99 mg CE/g, respectively) and leaf (3 and 1.22 mg CE/g, respectively) extracts. The HPLC analysis indicated that the main phenolic class was hydrolysable tannins (gallotannins) in leaf (79.39%, 8.90 mg/g) and flower (60.00%, 3.50mg/g) while the stem was characterized by the predominance of flavonoid class (61.38%, 1.86 mg/g) due to the high presence of catechin (36.91%, 1.12 mg/g). Antioxidant activities of the essential oil and the methanolic extract from different myrtle parts were evaluated by using DPPH radical scavenging, beta-carotene-linoleic acid bleaching, reducing power and metal chelating activity assays. In all tests, methanolic extracts of different myrtle parts showed better antioxidant activity than essential oils.

Evolution of the yields and composition of essential oil from Portuguese myrtle (Myrtus comunis L.) through the vegetative cycle

The chemical composition of the essential oil of Portuguese myrtle was determined at different developmental stages of the plant: pre-flowering, flowering, unripe and ripe berries. The oil was extracted separately by Clevenger distillation from leaves, branches and berries. The yields vary from 0.33% to 0.74% for leaves, 0.02% to 0.19% for branches, and 0.11% to 0.23% for berries. The highest yields were obtained for the leaves in October, and for the berries in September; branches show similar values in the months of June, July and September, and the samples collected in May and October produced very little amount of oil. Altogether, September seems to be the month with the best yields for the three parts of the plant. The essential oils were analyzed by GC and GC/MS, and a total of thirty five components were identified. The major components were limonene+1,8-cineole [25.9% (berries)–39.5% (leaves)], myrtenyl acetate [6.6% (berries)–24.8% (leaves)], α-pinene [9.7% (berries)–21.5% (leaves)], and linalool [6.2% (leaves)–36.5% (berries)]. Portuguese myrtle belongs to the group of myrtles which are characterized by the presence of myrtenyl acetate as one of the major components.

Myrtucommulone from Myrtus communis exhibits potent anti-inflammatory effectiveness in vivo

Myrtucommulone (MC), a nonprenylated acylphloroglucinol contained in the leaves of myrtle (Myrtus communis), has been reported to suppress the biosynthesis of eicosanoids by inhibition of 5-lipoxygenase and cyclooxygenase-1 in vitro and to inhibit the release of elastase and the formation of reactive oxygen species in activated polymorphonuclear leukocytes. Here, in view of the ability of MC to suppress typical proinflammatory cellular responses in vitro, we have investigated the effects of MC in in vivo models of inflammation. MC was administered to mice intraperitoneally, and paw edema and pleurisy were induced by the subplantar and intrapleural injection of carrageenan, respectively. MC (0.5, 1.5, and 4.5 mg/kg i.p.) reduced the development of mouse carrageenan-induced paw edema in a dose-dependent manner. Moreover, MC (4.5 mg/kg i.p. 30 min before and after carrageenan) exerted anti-inflammatory effects in the pleurisy model. In particular, 4 h after carrageenan injection in the pleurisy model, MC reduced: 1) the exudate volume and leukocyte numbers; 2) lung injury (histological analysis) and neutrophil infiltration (myeloperoxidase activity); 3) the lung intercellular adhesion molecule-1 and P-selectin immunohistochemical localization; 4) the cytokine levels (tumor necrosis factor-alpha and interleukin-1beta) in the pleural exudate and their immunohistochemical localization in the lung; 5) the leukotriene B(4), but not prostaglandin E(2), levels in the pleural exudates; and 6) lung peroxidation (thiobarbituric acid-reactant substance) and nitrotyrosine and poly (ADP-ribose) immunostaining. In conclusion, our results demonstrate that MC exerts potent anti-inflammatory effects in vivo and offer a novel therapeutic approach for the management of acute inflammation.

Myrtucommulone from Myrtus communis induces apoptosis in cancer cells via the mitochondrial pathway involving caspase-9

Myrtucommulone (MC) is a unique, nonprenylated acylphloroglucinol contained in the leaves of myrtle (Myrtus communis). Here, we addressed the potential of MC to induce apoptosis of cancer cells. MC potently induced cell death of different cancer cell lines (EC(50) 3-8 microM) with characteristics of apoptosis, visualized by the activation of caspase-3, -8 and -9, cleavage of poly(ADP-ribose)polymerase (PARP), release of nucleosomes into the cytosol, and DNA fragmentation. MC was much less cytotoxic for non-transformed human peripheral blood mononuclear cells (PBMC) or foreskin fibroblasts (EC(50) cell death = 20-50 microM), and MC up to 30 microM hardly caused processing of PARP, caspase-3, -8 and -9 in human PBMC. MC-induced apoptosis was mediated by the intrinsic rather than the extrinsic death pathway. Thus, MC caused loss of the mitochondrial membrane potential in MM6 cells and evoked release of cytochrome c from mitochondria. Interestingly, Jurkat cells deficient in caspase-9 were resistant to MC-induced cell death and no processing of PARP or caspase-8 was evident. In cell lines deficient in either CD95 (Fas, APO-1) signalling, FADD or caspase-8, MC was still able to potently induce cell death and PARP cleavage. Conclusively, MC induces apoptosis in cancer cell lines, with marginal cytotoxicity for non-transformed cells, via the mitochondrial cytochrome c/Apaf-1/caspase-9 pathway.

Intra-specific biodiversity of Italian myrtle (Myrtus communis) through chemical markers profile and biological activities of leaf methanolic extracts

Methanolic extracts of Myrtus communis leaves from two Italian regions (Calabria and Sardinia) were processed to determine the content of myrtenol, linalool and eucalyptol. Among the Calabrian and Sardinian myrtle samples, linalool and eucalyptol chemotypes were prevalent. The extracts were also tested for antioxidant, antibacterial and antifungal activities. Myrtle leaves samples were dried and extracted through maceration. Partition chromatography was adopted to separate myrtenol, linalool and eucalyptol fractions. Analyses were performed through GC and GC-MS. Some of the samples showed a good scavenger activity evidenced by DPPH radical scavenging assay and beta-carotene bleaching test. Antibacterial and antifungal activities were generally weak. The phytochemical and biological characterization of all the extracts were determined with an aim to characterize the intra-specific biodiversity of myrtle populations.

Effects of in vivo antioxidant enzyme activities of myrtle oil in normoglycaemic and alloxan diabetic rabbits

In this study we aimed to evaluate the in vivo effects of myrtle oil (myrtii oleum) on the antioxidant enzymes such as superoxide dismutase and catalase, the levels of malondialdehyde in liver tissues as an index of lipid peroxidation and nitrite-nitrate levels in normoglycaemic and alloxan-induced diabetic and MO-treated rabbits. In our previous study, we assumed that MO with a dose of 50 mg/kg, possesses a hypoglycemic activity and this activity was independent from the effects of insulin. Myrtle oil exerts its hypoglycemic activity by enhanced glycolysis, glycogenesis and decreased glycogenolysis. What is more glucose load data strongly suggest that MO treatment produces hypoglycemia mainly by reducing intestinal absorption of glucose, so MO could be an alpha-glycosidase enzyme inhibitor which had a hypoglycaemic effect only on alloxan-induced diabetic rabbits on the fourth hour and on orally glucose loaded group. The major finding of this new study is that, MO may not offer any protection against oxidative stress during acute studies in normoglycemic and diabetic groups. Although the levels of superoxide dismutase and catalase enzyme activities did not change during acute studies in diabetes + MO group, there was a significant change at the end of 21 days. There is a very limited knowledge about MO and its effects on diabetes. Therefore, we tried to explain the mechanism that might underlie the protective effects of MO with this paper.

Ethnopharmacological survey of plants used in the traditional treatment of hypertension and diabetes in south-eastern Morocco (Errachidia province)

This survey was undertaken in the Errachidia province in south-eastern Morocco in order to inventory the main medicinal plants used in folk medicine to treat arterial hypertension and diabetes mellitus. Four hundred individuals who knew about and/or had used the medicinal plants for the indicated diseases, including some herbal healers, were interviewed throughout different regions of the province. The inventory of medicinal plants is summarized in a synoptic table, which contains the scientific, vernacular and common name of the plant, its ecological distribution, the part of the plant and the preparation used and the therapeutic indication. Extensive investigations have brought to light 64 medicinal plants belonging to 33 families; of these, 45 are used for diabetes, 36 for hypertension, and 18 for both diseases. Of these plants, 34% grow in the wild, 44% are cultivated, and 22% are not indigenous to the area and are brought from other parts of Morocco or from outside the country. The survey shows that 78% of the patients regularly use these medicinal plants. In this region, the most frequently used plants to treat diabetes include Ajuga iva, Allium cepa, Artemisia herba-alba, Carum carvi, Lepidium sativum, Nigella sativa, Olea europaea, Peganum harmala, Phoenix dactylifera, Rosmarinus officinalis, and Zygophyllum gaetulum, and those to treat hypertension include Ajuga iva, Allium cepa, Allium sativum, Artemisia herba-alba Asso, Carum carvi, Nigella sativa, Olea europea, Rosmarinus officinalis, Origanum majorana, Peganum harmala, and Phoenix dactylifera. The local people recognize the toxic plants and are very careful in using such plants, which are Citrullus colocynthis, Datura stramonium, Nerium oleander, Nigella sativa, Peganum harmala and Zygophyllum gaetulum. Our survey shows that traditional medicine in the south-eastern Moroccan population has not only survived but has thrived in the transcultural environment and intermixture of many ethnic traditions and beliefs.

Identification of molecular targets of the oligomeric nonprenylated acylphloroglucinols from Myrtus communis and their implication as anti-inflammatory compounds

Myrtucommulone (MC) and semimyrtucommulone (S-MC) are unique oligomeric, nonprenylated acylphloroglucinols contained in the leaves of myrtle (Myrtus communis). Although extracts of myrtle have been traditionally used in folk medicine for the treatment of various disorders, studies addressing select cellular or molecular pharmacological properties of these extracts or specific ingredients thereof are rare. Here, we show for the first time that MC and S-MC potently suppress the biosynthesis of eicosanoids by direct inhibiting cyclooxygenase-1 and 5-lipoxygenase in vitro and in vivo at IC50 values in the range of 1.8 to 29 microM. Moreover, we show that MC and S-MC prevent the mobilization of Ca2+ in polymorphonuclear leukocytes, mediated by G protein signaling pathways at IC50 values of 0.55 and 4.5 microM, respectively, and suppress the formation of reactive oxygen species and the release of elastase at comparable concentrations. The isobutyrophenone core of MC as well as S-MC was much less potent or even not active at all. In addition, MC or S-MC only partially inhibited peroxide formation or failed to block Ca2+ mobilization and elastase release when polymorphonuclear leukocytes were challenged with ionomycin that circumvents G protein signaling for cell activation. We conclude that, in view of their ability to suppress typical proinflammatory cellular responses, the unique acylphloroglucinols MC and S-MC from myrtle may possess an anti-inflammatory potential, suggesting their therapeutic use for the treatment of diseases related to inflammation and allergy.

Evaluation of antioxidant effect of different extracts of Myrtus communis L

Oxidative stress is involved in the pathogenesis of numerous diseases. Nevertheless, no optimal natural antioxidant has been found for therapeutics, therefore polyphenol antioxidants have been looked for in myrtle leaves, a plant that in folk medicine has been used as anti-inflammatory drug. Antioxidant-rich fractions were prepared from myrtle (Myrtus communis L.) leaves liquid-liquid extraction (LLE) with different solvents. All myrtle extracts were very rich in polyphenols. In particular, hydroalcoholic extracts contain galloyl-glucosides, ellagitannins, galloyl-quinic acids and flavonol glycosides; ethylacetate extract and aqueous residues after LLE are enriched in flavonol glycosides and hydrolysable tannins (galloyl-glucosides, ellagitannins, galloyl-quinic acids), respectively. Qualitative and quantitative analysis for the single unidentified compound was also performed. Human LDL exposed to copper ions was used to evaluate the antioxidant activity of the myrtle extracts. Addition of these extracts did not affect the basal oxidation of LDL but dose-dependently decreased the oxidation induced by copper ions. Moreover, the myrtle extracts reduce the formation of conjugated dienes. The antioxidant effect of three myrtle extracts decreased in the following order: hydroalcoholic extracts, ethylacetate and aqueous residues after LLE. The extracts had the following IC50: 0.36, 2.27 and 2.88 microM, when the sum of total phenolic compounds was considered after the correction of molecular weight based on pure compounds. Statistical analysis showed a significant difference among hydroalcoholic extracts vs. the ethylacetate and aqueous residues after LLE. These results suggest that the myrtle extracts have a potent antioxidant activity mainly due to the presence of galloyl derivatives.