Chemical composition and antimicrobial activity of Phyllanthus muellerianus (Kuntze) Excel essential oil

Ethnopharmacological relevance

Phyllanthus muellerianus (Kuntze) Excel (family Euphorbiaceae) stem bark is used in Cameroon by Baka pygmies as a remedy for wound healing and tetanus.

Aim of the study

To characterize the chemical composition and to evaluate the antimicrobial properties of the essential oil of the plant.

Materials and methods

The essential oil was extracted from the stem bark by dynamic head space and by hydrodistillation and characterized by GC and GC-MS analyses. The antimicrobial activity was evaluated on the basis of the minimum inhibitory concentration (MIC) and the minimum bactericidal–fungicidal concentration (MBC–MFC) by the micro and macrodilution methods. The following bacteria and fungi were used: Clostridium sporogenes ATCC 3584, Staphylococcus aureus ATCC 6538, Streptococcus mutans ATCC 25175, Streptococcus pyogenes ATCC 19615, Escherichia coli ATCC 10536, Candida albicans ATCC 10231, Candida albicans LM 450, Trichophyton mentagrophytes LM 230, Trichophyton rubrum LM 237, Microsporum canis LM 324.

Results

The hydrodistillation afforded 0.06% (dry weight basis) of pale yellow oil. Thirty-eight compounds representing 90.69% were identified. The major component (36.40%) was found to be (E)-isoelemicin, identified by comparison of its ¹H-NMR experimental data, with literature data. The oil showed good antibacterial activity against Clostridium Sporogenes, Streptococcus mutans and Streptococcus pyogenes with MIC ranging from 13.5 to 126 μg/ml. A weak antifungal activity (MIC 250 μg/ml) was found against Trichophyton rubrum, only.

Conclusions

The antimicrobial activity and the chemical composition of Phyllanthus muellerianus stem bark essential oil are reported for the first time.     

The essential oil of Senecio graveolens (Compositae): chemical composition and antimicrobial activity tests.

The chemical composition of the essential oil obtained from Senecio graveolens (Compositae) was analyzed by GLC-MS and the components identified were: isovaleraldehyde, alpha-pinene, alpha-phellandrene, alpha-terpinene, p-cymene, sabinene, gamma-terpinene, 1-methyl-4-isopropenylbenzene, terpinolene, terpinen-4-ol, piperitenone, alpha- and beta-eudesmol. The investigation by the agar-well diffusion method of the antimicrobial activity of the essential oil proved that it has antibacterial effects on Micrococcus luteus ATCC 9341, oxacillin-sensitive and oxacillin-resistant Staphylococcus aureus, as well as antifungal effects on clinically isolated Candida albicans. The minimal inhibitory concentration (MIC) values for M. luteus, oxacillin-sensitive S. aureus and C. albicans were 8.73, 10.91 and 2.13 x 10(-2) mg/ml, respectively. The antimicrobial activity related to known antibiotics was calculated. These results would be compatible with a potential concentration-dependent selectivity of antifungal effect of S. graveolens essential oil. Minimal bactericidal concentration (MBC) is above 87.3 mg/ml. Thus the MBC:MIC ratio would be clearly higher than 1 (above 8), indicating a bacteriostatic effect of the essential oil.     

Chemical composition and antimicrobial activity of the essential oil of Cryptomeria japonica

The composition and the antibacterial activity of the essential oil obtained from Cryptomeria japonica D. Don on oral bacteria were studied. The chemical composition of the essential oil was analysed by GC and GC-MS. Sixty-eight compounds accounting for 95.82% of the oil were identified. The main compounds in the oil were alpha-pinene (6.07%), sabinene (8.86%), terpinen-4-ol (9.77%), alpha-terpineol (6.13%), elemol (11.17%) and 10(15)-cadinen-4-ol (7.16%). The essential oil and some of its major compounds were tested for antimicrobial activity against 15 different genera of oral bacteria. The essential oil of C. japonica exhibited considerable inhibitory effects against all bacteria tested (MICs, 0.025-0.05 mg/mL; MBCs, 0.025-0.1 mg/mL), while its major compounds demonstrated various degrees of growth inhibition.     

Antioxidant and antimicrobial activity of the essential oil and methanol extracts of Achillea millefolium subsp. millefolium Afan. (Asteraceae)

The in vitro antimicrobial and antioxidant activities of the essential oil and methanol extracts of Achillea millefolium subsp. millefolium Afan. (Asteraceae) were investigated. GC-MS analysis of the essential oil resulted in the identification of 36 compounds constituting 90.8% of the total oil. Eucalyptol, camphor, alpha-terpineol, beta-pinene, and borneol were the principal components comprising 60.7% of the oil. The oil strongly reduced the diphenylpicrylhydrazyl radical (IC(50)=1.56 micro g/ml) and exhibited hydroxyl radical scavenging effect in the Fe(3+)-EDTA-H(2)O(2) deoxyribose system (IC(50)=2.7 micro g/ml). It also inhibited the nonenzymatic lipid peroxidation of rat liver homogenate (IC(50)=13.5 micro g/ml). The polar phase of the extract showed antioxidant activity. The oil showed antimicrobial activity against Streptococcus pneumoniae, Clostridium perfringens, Candida albicans, Mycobacterium smegmatis, Acinetobacter lwoffii and Candida krusei while water-insoluble parts of the methanolic extracts exhibited slight or no activity. This study confirms that the essential oil of Achillea millefolium possesses antioxidant and antimicrobial properties in vitro.     

Chemical composition and antimicrobial activity of the essential oil of Cordiaverbenacea D.C

Cordiaverbenacea D.C. (Boraginaceae) is found along the coastal regions of Brazil, from the Amazon basin to the southernmost state of Rio Grande do Sul. The aerial parts of this plant have been used in folk medicine since colonial times for their anti-rheumatic, anti-inflammatory, analgesic and healing properties. The objectives of this study were: the extraction of the essential oil of the aerial parts of this species and quantification of the yield thereof; the identification and quantification of the principal components of the essential oil; and the determination of its antimicrobial activity by plate diffusion method. The yield of essential oil was 0.19% (v/w) in relation to the fresh flowering aerial parts and 0.23% (v/w) of the leaves. The main constituents of the essential oil, identified by gas chromatography/mass spectrometry (GC/MS), were alpha-pinene (29.69%), trans-caryophyllene (25.27%) and aloaromadendrene (9.99%). The Gram-positive bacteria and yeast tested were sensitive to the essential oil of Cordiaverbenacea D.C., but most of the Gram-negative bacteria were resistant.     

Antimicrobial activity of essential oil and methanol extracts of Achillea sintenisii Hub. Mor. (Asteraceae)

The essential oil, obtained by Clevenger distillation, and water-soluble and water-insoluble parts of the methanol extracts of Achillea sintenisii Hub. Mor. were individually assayed for their antimicrobial activities against 12 bacteria and two yeasts, Candida albicans and C. krusei. No activity was exhibited by the water-soluble subfraction, whereas both the water-insoluble subfraction of the methanol extracts and the essential oil were found to be active against some test microorganisms studied. Since the essential oil possessed stronger activity than the other extracts tested, it was further fractionated and the fractions were evaluated for their antimicrobial activity, followed by GC-MS analysis, resulting in the identification of 32 compounds which constituted 90.2% of the total oil. The GC-MS analysis of the oil and its fractions revealed that the main components of the oil, e.g. camphor and eucalyptol, possessed appreciable activity against C. albicans and Clostridium perfringens. The fi ndings presented here also suggest that the other constituents of the oil, e.g. borneol and piperitone can also be taken into account for the activity observed.     

The in vitro antioxidant and antimicrobial activities of the essential oil and methanol extracts of Achillea biebersteini Afan. (Asteraceae)

The essential oil and methanol extracts from A. biebersteinii Afan. (Asteraceae) were evaluated for their antimicrobial and antioxidant activities in vitro. The oil showed stronger antimicrobial activity than the extracts. Their antioxidant features were also evaluated using diphenyl-1-picrylhydrazyl (DPPH), inhibition of superoxide and hydroxyl radicals and inhibition of the lipid peroxidation assays. Particularly, polar subfraction of the methanol extract showed antioxidant activity. The GC-MS analysis of the oil has resulted in the identification of 23 components; piperitone, eucalyptol, camphor, chrysanthenone and borneol were the main components. Antimicrobial activity tests carried out with the fractions of the oil showed that the activity was mainly observed in those containing eucalyptol and camphor, in particular, followed by borneol and piperitone.     

The composition, geographical variation and antimicrobial activity of Lippia javanica (Verbenaceae) leaf essential oils

Lippia javanica is widely distributed throughout South Africa where it is used extensively in traditional herbal preparations. An infusion of the leaves is commonly used as a decongestant for colds and coughs. A preliminary study indicated that the essential oil chemistry varies dramatically both within and between natural plant populations. As the antimicrobial activity may be directly related to the specific composition of the oil, the activity may also fluctuate. The aerial parts of Lippia javanica were collected from various localities in southern Africa to study the essential oil composition and the antimicrobial activity thereof. The hydrodistilled essential oils were analysed by GC/MS and a cluster analysis was performed on the essential oil dataset. From 16 samples (representing five natural populations), 5 chemotypes were identified; a myrcenone rich-type (36-62%), a carvone rich-type (61-73%), a piperitenone rich-type (32-48%), an ipsenone rich-type (42-61%) and a linalool rich-type (>65%). The myrcenone and linalool chemotypes have been mentioned in the literature but the carvone, ipsenone and piperitenone chemotypes have not previously been reported for Lippia javanica. Time kill studies were performed on three microbial respiratory isolates to document the scientific rationale of using Lippia to treat respiratory complaints in traditional herbal medicine. Klebsiella pneumoniae, Cryptococcus neoformans and Bacillus cereus showed reduction in microbial populations with the strongest bacteriostatic effect observed for Klebsiella pneumoniae.     

Composition and antimicrobial activity of Achillea clavennae L. essential oil

The volatile constituents of Achillea clavennae L. (Asteraceae), rare plant of Europe, have been analysed using GC/MS. Twenty- five components making up 81.6% of the oil were characterized with camphor (29.5%), myrcene (5.5%), 1,8-cineole (5.3%), beta-caryophyllene (5.1%) and linalool (4.9%) being the major constituents. The essential oil was evaluated for antibacterial and antifungal activities. The screening of the antimicrobial activity of essential oil was conducted by a disc diffusion test against Gram-positive (Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Streptococcus faecalis), Gram-negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis) and fungal organisms (Aspergillus niger, Aspergillus fumigatus, Candida albicans). The activity was more pronounced against Gram-negative and fungal organisms than against Gram-positive bacteria. A. clavennae oil was found to possess antimicrobial activity against Klebsiella pneumoniae, Pseudomonas aeruginosa and all fungal organisms.     

Composition and antimicrobial activity of Equisetum arvense L. essential oil

The volatile constituents of the sterile stems of Equisetum arvense L. (Equisetaceae) were investigated for the first time using GC, GC/MS and (13)C-NMR. Twenty-five compounds were identified. Hexahydrofarnesyl acetone (18.34%), cis-geranyl acetone (13.74%), thymol (12.09%) and trans-phytol (10.06%) were the major constituents. A disk diffusion method was used for the evaluation of the antimicrobial activity of this oil against a panel of microorganisms (bacteria: Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella enteritidis; fungi: Aspergillus niger and Candida albicans). The 1:10 dilution of the essential oil of Equisetum arvense L. was shown to possess a broad spectrum of a very strong antimicrobial activity against all tested strains.     

The antimicrobial activity of the essential oil from Achillea fragrantissima

Essential oil from Achillea fragrantissima exerted a bactericidic effect on several gram positive and gram negative bacterial strains, as well as on Candida albicans. The oil was fractionated on sillica gel columns by a gradient of ether in petrol ether (30 degrees C-40 degrees C). Two fractions which contained less polar compounds were active against C. albicans only. The fractions which contained more polar compounds inhibited the growth of all the microorganisms tested. One of these compounds was identified as terpinen-4-ol. Commercial terpinen-4-ol had a similar antimicrobial activity.     

Chemical composition and antimicrobial activity of the essential oils of Chrysanthemum indicum

Three essential oils from three samples: fresh, air-dried and processed flowers of Chrysanthemum indicum, obtained by hydrodistillation, were analyzed by GC-MS. The results show that major constituents of the three oils were 1,8-cineole, camphor, borneol and bornyl acetate, but the percentage of these compounds varied greatly because of the processing of flowers. The antimicrobial activity of essential oils from air-dried and processed flowers was evaluated against 15 microorganisms including three yeasts and seven clinical isolated strains using disc paper and broth microdilution methods. Our results show that both essential oils possessed significant antimicrobial effect, however, some difference in antimicrobial activity between two oils was observed for several microorganisms, which was attributed to the variation in percentage of the components. With higher percentage of camphor, the oil of the processed flowers exhibited, in many cases, greater bacteriostatic activity than that of the air-dried ones.     

Antimicrobial activity and chemical composition of essential oil from Hedychium coronarium

The essential oil from fresh and dried rhizomes of Hedychium coronarium on GC-MS analysis resulted in the identification of 44 and 38 constituents representing 93.91% and 95.41%, respectively. The major components of the essential oil from fresh and dried Hedychium coronarium rhizome were 1,8-cineole (41.42%, 37.44%), beta-pinene (10.39%, 17.4%) and alpha-terpineol (8.8%, 6.7%). The aromatic oil has antifungal as well as antibacterial effects. The antimicrobial activities of the essential oil were individually evaluated against four microorganisms, including two bacteria and two fungi. It was found that the antimicrobial activity was higher in the fresh sample than the dried. Both samples showed a better activity against Trichoderma sp. and Candida albicans than against the bacteria Bacillus subtilis and Pseudomonas aeruginosa.     

In vitro antimicrobial activity of extracts of four Achillea species: the composition of Achillea clavennae L. (Asteraceae) extract

The extracts of aerial parts of Achillea clavennae, Achillea holosericea, Achillea lingulata and Achillea millefolium (hexane:ether:methanol=1:1:1) have been tested for antimicrobial activity in a disk diffusion assay against five bacteria (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella enteritidis) and two fungi (Aspergillus niger and Candida albicans). Extracts of all four species possessed a broad spectrum of antimicrobial activity against all tested strains. The composition of the extract of Achillea clavennae, which showed the strongest activity, was investigated and the structures of isolated compounds were elucidated by spectral means (1D and 2D NMR, UV, IR and MS). The extract yielded alkanes, fatty acids, monoterpenes, guaiane sesquiterpenes (rupicolin A and B, 1-deoxy-1alpha-peroxy-rupicolin A and B), and flavonoids (apigenin and centaureidin). This study confirms the ethnopharmacological use of plants from this genus and places Achillea clavennae L. on the same level as the recognized Achillea millefolium.     

In vitro antimicrobial activity of Zingiber cassumunar (Plai) oil and a 5% Plai oil gel

The essential oil of Zingiber cassumunar (Plai oil) exhibits antimicrobial activity against a wide range of Gram-positive and Gram-negative bacteria, dermatophytes and yeasts. Dermatophytes were found to be the most susceptible microorganisms followed by yeasts, whereas bacteria were the least susceptible. The mean diameter of the inhibition zone determined by the disc diffusion screening method increased with increasing Plai oil concentration between 6.25 and 50 vol %. The minimum bactericidal concentration (MBC) determined by the broth macrodilution method ranged from 0.62 to 2.5 vol % for Plai oil and from 52 to 79 mg/mL for the 5 wt % Plai oil gel, whereas the minimum fungicidal concentration (MFC) ranged from 0.31 to 1.25 vol % for Plai oil and from 13.8 to 39.5 mg/mL for the 5% Plai oil gel.     

Chemical composition and antibacterial activity of essential oil of Pulicaria odora L

The chemical composition of the volatile oil constituent from Pulicaria odora L. roots has been analyzed by GC/MS. Twenty-seven components were identified, being thymol (47.83%) and its derivative isobutyrate (30.05%) the main constituents in the oil. Furthermore, the oil was tested against seven bacteria at different concentrations. Results showed that the oil exhibited a significant antibacterial activity.     

Anticonvulsant activity and chemical composition of Artemisia dracunculus L. essential oil

Artemisia dracunculus L. (Asteraceae) has been used orally as an antiepileptic remedy in Iranian folkloric medicine. The anticonvulsant potential and composition of the essential oil obtained from the aerial parts of the plant were assessed in this study. The essential oil exerted dose- and time-dependent antiseizure activity in both maximal electroshock (MES) and pentylenetetrazole models of experimental seizures with ED50 values of 0.84 and 0.26 ml/kg, respectively. At some anticonvulsant doses, the essential oil produced sedation and motor impairment assessed by rotarod test. Gas chromatography (GC)/mass spectrometry (MS) analysis of the essential oil revealed the presence of trans-anethole (21.1%), alpha-trans-ocimene (20.6%), limonene (12.4%), alpha-pinene (5.1%), allo ocimene (4.8%), methyl eugenol (2.2%), beta-pinene (0.8%), alpha-terpinolene (0.5%), bornyl acetate (0.5%) and bicyclogermacrene (0.5%) as the main components. The observed anticonvulsant and sedative effects could be related to the presence of monoterpenoids in the essential oil.     

Antimicrobial activity and chemical composition of Mentha pulegium L. essential oil

ETHNOPHARMACOLOGICAL RELEVANCE: The flowering aerial parts of Mentha pulegium L. (Labiatae) has been traditionally used for its antiseptic properties for treatment of infectious diseases. AIM OF THE STUDY: In order to validate its antiseptic properties with respect to traditional uses, we have screened the antimicrobial activity of flowering aerial parts of Mentha pulegium L. essential oil against different microorganisms. MATERIALS AND METHODS: This oil was obtained using hydrodistillation method and analyzed by GC and GC/MS. The antimicrobial activity was achieved using disc diffusion method and microbroth dilution assay. RESULTS: Analysis of the essential oil revealed the presence of piperitone (38.0%), piperitenone (33.0%), alpha-terpineol (4.7%), and pulegone (2.3%) as the major components. The results showed a significant activity against microorganisms especially Gram-positive bacteria with inhibition zones and minimal inhibitory concentration values in the range of 8-21mm and 0.25-4mul/ml, respectively, whereas the least susceptible were Gram-negative bacteria especially Escherichia coli. CONCLUSIONS: This investigation showed that the oil of Mentha pulegium L. has a potent antimicrobial activity and the Iranian Mentha pulegium L. oil belongs to piperitone/piperitenone type. Further research is required to evaluate the practical values of therapeutic applications.     

Composition and antimicrobial activity of the essential oil of Ballota pseudodictamnus L. Bentham

The chemical composition of the essential oil of Ballota pseudodictamnus obtained from the aerial parts was analysed by GC/MS. From the 52 identified constituents of the oil, caryophyllene oxide, phytol and gamma-muurolene were the major components. Furthermore, the essential oil was investigated for its antimicrobial activity.     

Chemical composition and antimicrobial activity of the essential oils from two species of Eucalyptus

The leaf-essential oil from Eucalyptus robusta and E. saligna, the latter in two phenologic stages, were analysed by gas chromatography coupled to mass spectrometry (GC-MS). The major constituent in E. robusta oil was the monoterpene alpha-pinene (73.0% of the total amount). The oil composition of the E. saligna was dependent of the phenologic stage. In the vegetative phase, the major constituents were p-cymene (54.2%) and gamma-terpinene (43.8%), while during the blossoming alpha-pinene became the major constituent followed by p-cymene (22.5%). Additionally, the antimicrobial activity for all three oils was evaluated against Staphylococcus aureus, Escherichia coli and Candida albicans. The E. robusta oil presented the highest growth inhibition for all the microorganisms tested.