Antibacterial and antioxidant activities of a novel enol ether nor-sesquiterpene isolated from Myrtus nivellei Batt. & Trab.

Myrtus nivellei is a plant traditionally used to treat diseases including infection of microbial origin. Several M. nivellei Batt. & Trab. extracts (dichloromethane, methanol and ethanol/water) were screened for their activity against 36 microorganisms, including strains resistant to antibiotics. These extracts inhibited on average 15 bacteria strains with minimum inhibition concentrations (MICs) ranging from 0.07 to 1.20 mg/mL. Bioassay guided fractionation was carried out with bioautography on TLC plates using four pathogenic bacteria strains, and following chromatographies (CPC and HPLC) led to the isolation of two novel enol ether nor-cadinane sesquiterpenes from the dichloromethane extract. The major compound (1) showed a strong antibacterial activity. Minimal inhibition concentration and minimal bactericidal concentration (MBC) values were determined against four bacteria: Acinetobacter baumanii, Stenotrophomonas maltophilia, Yersinia pseudotuberculosis and Staphylococcus lugdunensis. The best activity was observed against Acinetobacter baumanii with a MIC value of 9.7 µg/mL. This novel compound was also very active against a Staphylococcus aureus strain resistant to amoxicillin (MIC 19.5 µg/mL). In addition, compound 1 showed a very high antioxidant activity with both DPPH and metal chelate methods.

A new cineol derivative, polyphenols and norterpenoids from Saharan myrtle tea (Myrtus nivellei): Isolation, structure determination, quantitative determination and antioxidant activity.

The phytochemical profile of decoction and infusion, obtained from the dried leaves of M. nivellei, consumed as tea in Saharan region, was characterized by UHPLC-PDA-HRMS. Fourteen compounds were characterized and, to confirm the proposed structures a preparative procedure followed by NMR spectroscopy was applied. Compound 3 (2-hydroxy-1,8-cineole disaccharide) was a never reported whereas a bicyclic monoterpenoid glucoside (2), two ionol glucosides (1 and 12), a tri-galloylquinic acid (4), two flavonol glycosides (5 and 9), and a tetra-galloylglucose (7), were reported in Myrtus spp. for the first time. Five flavonol O-glycosides (6, 8, 10-11, and 14) togheter a flavonol (13) were also identified. Quantitative determination of phenolic constituents from decoction and infusion has been performed by HPLC-UV-PDA. The phenolic content was found to be 150.5 and 102.6mg/g in decoction and infusion corresponding to 73.8 and 23.6mg/100mL of a single tea cup, respectively. Myricetin 3-O-ß-d-(6″-galloyl)glucopyranoside (5), isomyricitrin (6) and myricitrin (8) were the compounds present in the highest concentration. The free-radical scavenging activities of teas and isolated compounds was measured by the DPPH assay and compared with the values of other commonly used herbal teas (green and black teas). Decoction displayed higher potency in scavenging free-radicals than the infusion and green and black teas.

Antioxidant antileishmanial cytotoxic and antimicrobial activities of a local plant Myrtus nivellei from Algeria Sahara

Objective To study the phytochemical constituents and in vitro biological activities of hydromethanolic extract and fractions from Algerian Sahara Myrtus nivellei (M. nivellei) collected in Hoggar region and to identify the active fraction that can act as an alternative of commonly used antibiotics and as antileishmanial or antioxidant agents. Methods Phytochemical screening of M. nivellei aerial parts was realised according to the literature. Extract was firstly prepared by using aqueous methanol then fractionated with ethyl acetate and butanol solvents. Total phenolics, tannis and flavonoids, of the hydromethanolic extract and their fractions were determined by Folin–Ciocalteu method as gallic acid equivalents and by aluminium chloride as rutin equivalent respectively. Extract and fractions were tested for their antimicrobial and antiparasital activities against standard bacteria using agar diffusion method and two kinds of leishmania visceral and cutaneous. The antioxidant activities were realized using phosphomolybdenum, FRAP and DPPH tests. Results Preliminary phytochemical screening exhibited the presence of flavonoids, tannins, saponins, and alkaloids. The experimental results showed that plant extract and fractions were high in phenolic compounds and exhibited an important role as antioxidant, antimicrobial and had a moderate antileishmanial activity. Conclusions These observations lead us toward more studies in this field, so that we can get more benefits from our local Algerian medicinal plants.

Antioxidant antileishmanial cytotoxic and antimicrobial activities of a local plant Myrtus nivellei from Algeria Sahara

Objective: To study the phytochemical constituents and in vitro biological activities of hydromethanolic extract and fractions from Algerian Sahara Myrtus nivellei (M. nivellei) collected in Hoggar region and to identify the active fraction that can act as an alternative of commonly used antibiotics and as antileishmanial or antioxidant agents. Methods: Phytochemical screening of M. nivellei aerial parts was realised according to the literature. Extract was firstly prepared by using aqueous methanol then fractionated with ethyl acetate and butanol solvents. Total phenolics, tannis and flavonoids, of the hydromethanolic extract and their fractions were determined by Folin–Ciocalteu method as gallic acid equivalents and by aluminium chloride as rutin equivalent respectively. Extract and fractions were tested for their antimicrobial and antiparasital activities against standard bacteria using agar diffusion method and two kinds of leishmania visceral and cutaneous. The antioxidant activities were realized using phosphomolybdenum, FRAP and DPPH tests. Results: Preliminary phytochemical screening exhibited the presence of flavonoids, tannins, saponins, and alkaloids. The experimental results showed that plant extract and fractions were high in phenolic compounds and exhibited an important role as antioxi-dant, antimicrobial and had a moderate antileishmanial activity. Conclusions: These observations lead us toward more studies in this field, so that we can get more benefits from our local Algerian medicinal plants.

The Genus Myrtus L. in Algeria: Composition and Biological Aspects of Essential Oils from M. communis and M. nivellei: A Review.

The genus Myrtus L. (Myrtaceae family) comprises two species, Myrtus communis L. (known as common myrtle) growing wild all around the Mediterranean basin and Myrtus nivellei Batt. and Trab. (known as Saharan myrtle), found in central Sahara. Only one country, Algeria, hosts both species, M. communis in the North and M. nivellei in the South. The aim of this review was to collect, summarize, and compare the main results reported relative to the essential oils isolated from aerial parts of both species: botanical aspects, habitat, traditional use, chemical composition, new compounds, antimicrobial activity, antioxidant activity, anti-inflammatory effect, and insecticidal activity. Both essential oils have potential applications in human health.

New compounds, chemical composition, antifungal activity and cytotoxicity of the essential oil from Myrtus nivellei Batt. & Trab., an endemic species of Central Sahara.

ETHNOPHARMACOLOGIC RELEVANCE: Myrtus nivellei Batt. & Trab. (Myrtaceae) known as Sahara myrtle is appreciated by the Touaregs as medicinal plant. Infusion of leaves is employed against diarrhea and blennorrhea. Crushed leaves added to oil or to butter ointment have been traditionally used for the treatment of dermatosis. Aim of the study is to consider the traditional medicinal uses and the lack of scientific studies on their biological activities, the present study was designed to elucidate the chemical composition, the antifungal activity of its essential oils against fungi responsible for human infections, as well as, its cytotoxicity in the mammalian keratinocytes. MATERIALS AND METHODS: Chemical analysis of Myrtus nivellei essential oil isolated by hydrodistillation of aerial parts (leaves and flowers), was carried out using a combination of chromatographic (CC, GC with retention indices) and spectroscopic techniques (MS, (13)C NMR, 2D NMR). The antifungal activity was evaluated by using broth macrodilution methods for yeasts and filamentous fungi. Cytotoxicity was tested in HaCaT keratinocytes through the MTT assay. RESULTS: Ten samples coming from two localities of harvest were investigated. The chemical composition was largely dominated by 1,8-cineole (33.6-50.4%) and limonene (17.5-25.0%). The structure of two new compounds bearing the isoamylcyclopentane skeleton has been elucidated. The oil was more active against Cryptococcus neoformans with MIC of 0.16µL/mL followed by dermatophytes, with MICs of 0.64 and 1.25µL/mL. Furthermore, evaluation of cell viability showed no cytotoxicity in HaCaT keratinocytes at concentrations up to 1.25µL/mL. CONCLUSIONS: The composition of Myrtus nivellei oil differed from that of Myrtus communis. The structure of two di-nor-sesquiterpenoids has been elucidated. It was possible to find appropriate doses of Myrtus nivellei oil with both antifungal activity and very low detrimental effect on keratinocytes. These findings add significant information to the pharmacological activity of Myrtus nivellei essential oils, specifically to its antifungal properties, thus justifying and reinforcing the use of this plant in traditional medicine.