Phytochemical and Bioactivities of Myrtus communis : A Review

CrossRef, Scientific Indexing Services (SIS), Google Scholar, Index Copernicus International (ICI), Directory of Research Journal Indexing (DRJI), CiteFactor, Scientific Journal Impact Factor (SJIF), General Impact Factor, Journal Factor, Cosmos Impact Factor, PKP Index, AJIFACTOR Indexing, etc. Myrtus communis L. plant is from Myrtaceae family and it is known as True Myrtle. M. communis extracts and essential oil are important in drug development with some pharmacological activities in the Middle East. For a long time M. communis has been used in traditional medicines for the treatment of lung disorders and as an antiseptic, antiinflammatory, mucolytic, carminative and astringent remedy. It has recently antioxidant, analgesic, antibacterial and antifungal activities and larvicide, insecticide and repellency effects. Myrtucommulone A & B and semi-myrtucommulone are oligomeric, nonprenylatedacylphloroglucinols which are reported from leaves of myrtle. α-pinene, 1,8cineol, limonene and linalool were identified as the major constituents in M. communis essential oil.


INTRODUCTION
Myrtaceae family includes 100 genera and 3000 species. Myrtus genus belongs to this family of evergreen shrubs or small trees, which grow up to 5-m tall spontaneously. It is native to Southern Europe, North Africa and Western Asia and also distributed in South America, North western Himalaya and Australia (Romani et al, 1999). Myrtle (Myrtus communis L.) is an aromatic evergreen perennial shrub orsmall tree belonging to the Myrtaceae growing in temperate, tropical and subtropical regions (Romani et al, 1999). The plant is 2.4-3m high and branches forming a close full head, thickly covered with leaves (Sumbul, 2011). Leaves are small and green and fruits are smalland dark. The evergreen leaves are 2-5 cm long and aromatic after crushing such as in the case of myrrh or eucalyptus. The taste of it is bitter and intensive (Özkan & Güray, 2009) which is mainly due to its astringency. Flowers are starlike, white or pinkish and very fragrant. The round blueblack berry fruit contains several seeds. The pollination is done by insects, and the seeds are dispersed by birds that eat the berries (Satyavati et al, 1976). The seeds are dispersed by birds that eat the berries. It is a traditional medicinal plant for the Tuareg people. Several botanists do not consider Myrtus nivellei sufficiently distinct to be treated as a separate species. It is listed as an endangered species (Ebrahimabadi et al, 2016).
Myrtus communis , the Common Myrtle, is widely cultivated as an ornamental plant for use as a shrub in gardens and parks (Jabri et al, 2016). It is often used as a hedge plant, with its small leaves shearing cleanly. When trimmed less frequently, it has numerous flowers in late summer. It requires a long hot summer to produce its flowers (Acosta-Motos et al,2016). It is traditionally used as an antiseptic, disinfectant drug and hypoglycaemic agent (Elfellah et al , 1984). Different parts of the plant have been used in the food industry, as flavouring meat and sauces, and the cosmetic industry (Chalchat et al, 1998). The present review attempts to give an overview on the phytochemical, pharmacological effects of this plant.

Anti-bacterial effect
The therapeutic effects of Myrtus communis L 2% (in metronidazole base) with only metronidazole vaginal gel 0.75% on bacterial vaginosis was compared. Findings of the study showed that treatment with a combination of Myrtus communis L or Berberis vulgaris in metronidazole base improve the efficacy of bacterial vaginosis therapy (Masoudi et al, 2014).

Anti-oxidant, and anti-tumor properties
An endophytic strain of Neofusicoccumaustrale recovered from a myrtle branch was selected based on the bioactivity of its culture extracts, and found to produce myrtucommulones A and D. The availability of a microbial strain to be cultured in vitro may provide access to more substantial amounts of these products for further investigations in view of their possible pharmaceutical use (Nicoletti et al, 2014).

Repellency effect
Repellency effect of this plant was examined and it was demonstrated that Essential oil of Myrtus communis have repellency effect, even with 10% concentration of essential oil (Kayedi et al, 2014).

Antifungal, anti-biofilm and adhesion activity
The adhesion activity, the biofilm formation and the action of the Myrtus communis L was evaluated. The antimycotic activity of the EO towards the three species was also evaluated, and the results were compared with the minimum inhibitory concentration of six antimycotics. The activity of the EO against C. albicans and C. parapsilosis was better than that obtained against C. tropicalis; moreover, the strains used in the assay were adhesive and biofilm producer, and the effect of myrtle EO on the biofilm formation yielded encouraging results (Cannas et al, 2014). The antileishmanial effects of the essential oil and methanolic extract of Myrtus communis against Leishmania tropica on an in vitro modelwas evaluated. Essential oil indicated a more cytotoxic effect as compared with the methanolic extract of M. communis. The findings of the present study demonstrated that M. communis might be a natural source for production of a new leishmanicidal agent

Antifungal and Herbicidal Effects
The herbicidal effects of the oils on the seed germination and seedling growth of Amaranthus retroflexus L., Chenopodium album L., Cirsiumarvense (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.

Anti-inflammatory effect
Several studies have indicated the anti-inflammatory properties of the essential oil of M. communis in animal models (Rossi et al,2009;Amira et al, 2012). The antiinflammatory effect of aqueous and ethanolic extracts of the aerial parts of M. communis L. using xylene-induced ear oedema and cotton pellet tests. The extracts showed significant activity against acute inflammation that was dose dependent for the aqueous extract. The ethanolic (0.05 g/kg) and aqueous extracts (0.005, 0.015 and 0.03 g/kg) proved antiinflammatory effects against chronic inflammation. The extract effectively and significantly reduced cotton pellet-induced granuloma. Therefore, this activity may have occurred through the proliferative phase of the inflammation. Furthermore, topical use of the essential oil of M. communis is reported to cause a significant decrease in the ear oedema and cotton pelletinduced granuloma (Maxia et al, 2011).

Cardiovascular effect
The aqueous leaf extract of M. communis showed a negative inotropic effect on isolated guinea pig atria; this effect was not reversed by atropine. Besides, the total extract induced concentration-dependent depressive effect in anaesthetized rabbit which was not attenuated by propranolol, cimetidine and atropine but blocked by theophyline. These effects could be due to the presence of an adenosine-like compound in this extract as studied by Al-Jeboory (Al-Jeboory et al, 1985).

Effects on impotence
M. communis is used traditionally as a treatment of sexual impotence, a study was performed to evaluate the effect of the hydroalcoholic extract of the leaves on pituitary-gonad axis in adult male rats. In the study, doses of 0.75, 1.5 and 3mg leaf extract/kg body weight were administrated orally. The analysis of the concentrations of FSH, LHand testosterone by radio immunoassay indicated that administration of M. communis at 1.5 and 3mg/kg doses led to a significant increase in the level of testosterone (p<0.05), whereas no significant difference was observed in the concentration of LH or FSH hormones. The mechanism of action by which M communis leaf extract causes an increase in testosterone hormone level is not yet clear but it could be related to the presence of compounds such as flavonoid, ascorbic acid and myricetin (inhibition of aromatase activity), linoleic, oleic and palmitic acids (inhibition of 5alpha reductase activity). 1,8-Cineole and delta-cadinene (the cytochrome-P450 Inducer) could also be involved in the activity described (Shariati et al., 2010).

CONCLUSION
M. communis has many pharmacological functions including anti-inflammatory, analgesic, antidiabetic, antibacterial, antifungal and antioxidant activities, among others. As the current information shows, it is also possible that monoterpenoids from the essential oil and nonprenylatedacyl phloroglucinols isolated from the leaves might be useful in the development of new drugs to treat various diseases.