Antimicrobial, Antioxidant, and Cytotoxic Activities of Ocimum forskolei and Teucrium yemense (Lamiaceae) Essential Oils.

Background:Ocimum forskolei and Teucrium yemense (Lamiaceae) are used in traditional medicine in Yemen. Methods: The chemical composition, antimicrobial, antioxidant and cytotoxic activities of the essential oils isolated from the leaves of Ocimum forskolei Benth. (EOOF) and two different populations of Teucrium yemense Deflers., one collected from Dhamar province (EOTY-d), and another collected from Taiz (EOTY-t) were investigated. The antimicrobial activities of the oils were evaluated against several microorganisms with the disc diffusion test or the broth microdilution test. The essential oils were screened for in-vitro cytotoxic activity against human tumor cells. EOOF and EOTY-d were screened for free-radical-inhibitory activity using the DPPH radical scavenging assay. Results: Sixty-four compounds were identified in (EOOF) representing 100% of the oil content with endo-fenchol (31.1%), fenchone (12.2%), τ-cadinol (12.2%), and methyl (E)-cinnamate (5.1%) as the major compounds. In EOTY-d, 67 compounds were identified, which made up 91% of the total oil. The most abundant constituents were (E)-caryophyllene (11.2%), α-humulene (4.0.%), γ-selinene (5.5%), 7-epi-α-selinene (20.1%), and caryophyllene oxide (20.1%), while the major compounds in EOTY-t were α-pinene (6.6%), (E)-caryophyllene (19.1%) α-humulene (6.4%), δ-cadinene (6.5%), caryophyllene oxide (4.3%), α-cadinol (9.5%), and shyobunol (4.6%). The most sensitive microorganisms for EOOF were B. subtilis, S. aureus, and C. albicans with inhibition zones of 34, 16, and 24 mm and MIC values of, 4.3 mg/mL, 4.3 mg/mL, and 8.6 mg/mL, respectively. EOTY-t showed antimicrobial activity against S. aureus, B. cereus, A. niger, and B. cinerea with MIC values of 0.156, 0.156, 0.313 and 0.313 mg/mL, respectively. Neither essential oil showed remarkable radical inhibition (IC50 = 31.55 and 31.41 µL/mL). EOTY-d was active against HT-29 human colorectal adenocarcinoma cell lines with IC50 = 43.7 µg/mL. Consistent with this, EOTY-t was active against both MCF-7 and MDA-MB-231 human breast adenocarcinoma cells. Conclusions: The antimicrobial activity of Ocimum forskolei essential oil against B. subtilis and C. albicans is consistent with its traditional use in Yemeni traditional medicine to treat skin infections. Both O. forskolei and T. yemense show wide variations in their respective essential oil compositions; there remains a need to investigate both species botanically, genetically, and phytochemically more comprehensively.

Chemotypic Characterization and Biological Activity of Rosmarinus officinalis.

Rosemary (Rosmarinus officinalis L.) is a popular herb in cooking, traditional healing, and aromatherapy. The essential oils of R. officinalis were obtained from plants growing in Victoria (Australia), Alabama (USA), Western Cape (South Africa), Kenya, Nepal, and Yemen. Chemical compositions of the rosemary oils were analyzed by gas chromatography-mass spectrometry as well as chiral gas chromatography. The oils were dominated by (+)-α-pinene (13.5%-37.7%), 1,8-cineole (16.1%-29.3%), (+)-verbenone (0.8%-16.9%), (-)-borneol (2.1%-6.9%), (-)-camphor (0.7%-7.0%), and racemic limonene (1.6%-4.4%). Hierarchical cluster analysis, based on the compositions of these essential oils in addition to 72 compositions reported in the literature, revealed at least five different chemotypes of rosemary oil. Antifungal, cytotoxicity, xanthine oxidase inhibitory, and tyrosinase inhibitory activity screenings were carried out, but showed only marginal activities.

The Essential Oil Compositions of Ocimum basilicum from Three Different Regions: Nepal, Tajikistan, and Yemen.

The aerial parts of Ocimum basilicum L. were collected from four different geographical locations, Sindhuli and Biratnagar (Nepal), Chormaghzak village (Tajikistan), and Sana'a (Yemen). The essential oils were obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry. A cluster analysis of 179 essential oil compositions revealed six major chemotypes: Linalool, eugenol, estragole, methyl eugenol, 1,8-cineole, and geraniol. All four of the basil oils in this study were of the linalool-rich variety. Some of the basil oils were screened for bioactivity including antimicrobial, cytotoxicity in human cancer cells, brine shrimp lethality, nematicidal, larvicidal, insecticidal, and antioxidant. The basil oils in this study were not notably antibacterial, cytotoxic, antioxidant, nor nematicidal, but were active in the brine shrimp lethality test, and did show larvicidal and insecticidal activities.

Evaluation of Antileishmanial Activity of Albaha Medicinal Plants against Leishmania amazonensis.

Sixteen methanolic extracts obtained from thirteen plant species, selected either from ethnobotanical or chemotaxonomical data, were screened for their antileishmanial activity against Leishmania amazonensis. The cytotoxic activity against normal peritoneal macrophages from normal BALB/c mice was also determined. Eight extracts had IC50 values ranging from <12.5 to 37.8 µg/mL against promastigotes. Achillea biebersteinii flower, Euphorbia helioscopia, and Solanum incanum leaf extracts showed antileishmanial activities with IC50 between <12.5-26.9 µg/mL and acceptable selectivity indices of 8-5. The other leishmanicidal plant extracts, with IC50 ranging from 18.0 to 29.5 µg/mL, exhibited low selectivity indices.

A Survey of Chemical Compositions and Biological Activities of Yemeni Aromatic Medicinal Plants.

Yemen is a small country located in the southwestern part of the Arabian Peninsula. Yemen's coastal lowlands, eastern plateau, and deserts give it a diverse topography, which along with climatic factors make it opulent in flora. Despite the introduction of Western medicinal system during the middle of the twentieth century, herbal medicine still plays an important role in Yemen. In this review, we present a survey of several aromatic plants used in traditional medicine in Yemen, their traditional uses, their volatile chemical compositions, and their biological activities.

Composition of essential oil from Tagetes minuta and its cytotoxic, antioxidant and antimicrobial activities.

The essential oil from the leaves of Tagetes minuta L., growing wild in Yemen, was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. A total of 28 compounds were identified representing 74.2% of total oil composition. Major components of the essential oil were (Z)-ocimenone (15.9%), (E)-ocimenone (34.8%), (Z)-beta-ocimene (8.3%), limonene (2.3%), (Z)-tagetone (1.8%), dihydrotagetone (1.4%) and an unidentified dimethylvinylketone derivative (20.6%). The oil showed moderate cytotoxic activity against MCF-7 breast tumor cells, with an IC50 of 54.7 +/- 6.2 microg/mL. In the DPPH radical scavenging assay, T. minuta oil showed potent antiradical activity with an IC50 value of 36 microg/mL. Antimicrobial activity was also investigated on several microorganisms, and the essential oil exhibited high activity against methicillin-resistant Staphylococcus aureus (MRSA) with an inhibition zone of 23 mm. It also exhibited remarkable antifungal activity against Candida albicans with an inhibition zone of 26 mm.

Chemical composition, antimicrobial, antioxidant and cytotoxic activity of essential oils of Plectranthus cylindraceus and Meriandra benghalensis from Yemen.

The chemical composition, antimicrobial, antioxidant and cytotoxic activities of the essential oils isolated from the leaves of Plectranthus cylindraceus Hoechst. ex. Benth. (EOPC) and Meriandra benghalensis (Roxb.) Benth. (EOMB) were investigated. Sixteen compounds were identified in P. cylindraceus oil representing 94.5% of the oil content with thymol (68.5%), terpinolene (5.3%), beta-selinene (4.7%), beta-caryophyllene (4.0%), delta-cadinol (2.1%), and arcurcumene (1.7%) as the major compounds. In M. benghalensis oil, 12 compounds were identified, which made up 82.0% of the total oil. The most abundant constituents were camphor (43.6%), 1,8-cineole (10.7%), alpha-eudesmol (5.8%), caryophyllene oxide (5.8%), camphene (5.3%) and bomeol (3.4%). The antimicrobial activities of both oils were evaluated against five microorganisms with the disc diffusion test, the broth micro-dilution method and a semiquantitative bioautographic test. The most sensitive microorganisms for P. cylindraceus oil were S. aureus, B. subtilis, and C. albicans with inhibition zones of 38, 42, and 43 mm and MIC values of 0.39, 0.18, and, 0.18 microL/mL, respectively. M. benghalensis oil showed weak to moderate activity against the tested microorganisms. 2,2-Diphenyl-l-picrylhydrazyl (DPPH) assay was employed to study the potential antioxidant activities of both oils. The antioxidant activity of P. cylindraceus oil (IC50 34.5 microg/mL) appeared to be higher than that of M. benghalensis oil (IC50 935 microg/mL). At a concentration of 100 microg/mL, EOMB showed a stronger cytotoxic activity, with growth inhibition of 71% against HT29 tumor cells, than EOPC (18%).

Chemical composition and biological activity of essential oil from Pulicaria undulata from Yemen.

The chemical composition of the essential oil obtained from the leaves of Pulicaria undulata Gamal Ed Din (syn P. orientalis sensu Schwartz and P. jaubertii Gamal Ed Din) was analyzed by GC-MS. Major compounds of P. undulata oil were the oxygenated monoterpenenes, carvotanacetone (91.4%) and 2,5-dimethoxy-p-cymene (2.6.%). The antimicrobial activity of the essential oil was evaluated against six microorganisms, Escherichia coli Pseudomonas aeruginosa, Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus subtilis, and Candida albicans, using disc diffusion and broth microdilution methods. The oil showed the strongest bactericidal activity against Staphylococcus aureus and methicillin-resistant S. aureus, as well as Candida albicans. The essential oil showed moderate cytotoxic activity against MCF-7 breast tumor cells, with an IC50 of 64.6 +/- 13.7 microg/mL. Bioautographic assays were used to evaluate the acetylcholinesterase inhibitory effect as well as antifungal activity of the oil against Cladosporium cucumerinum.

Chemical composition, antimicrobial, antiradical and anticholinesterase activity of the essential oil of Pulicaria stephanocarpa from Soqotra.

The chemical composition of the hydrodistilled leaf essential oil from Pulicaria stephanocarpa Balf. Fil was determined by GC-MS analysis, and its antimicrobial, antioxidant and anticholinesterase (AChE) activities were evaluated. Eighty-three compounds were identified representing 97.2% of the total oil. (E)-Caryophyllene 13.4%, (E)-nerolidol 8.5%, caryophyllene oxide 8.5%, alpha-cadinol 8.2% spathulenol 6.8% and tau-cadinol 4.7%, were the main components. Antimicrobial activity of the oil, evaluated using the disc diffusion and broth dilution methods, demonstrated the highest susceptibility on Gram-positive bacteria and Candida albicans. The free radical scavenging ability of the oil was assessed by the DPPH assay to show antiradical activity with IC50 of 330 microg/mL. Moreover, the oil revealed an AChE inhibitory activity of 47% at a concentration of 200 microg/mL using Ellman's method.

Comparative analysis of the oil and supercritical CO(2) extract of Schinus molle L. growing in Yemen.

In this study, we report the preliminary data on the chemical composition of Yemeni Schinus molle L. volatile oil obtained by supercritical extraction with carbon dioxide (40°C and 90 bar), SFE, and by hydrodistillation (HD). The composition of the volatile oil has been analysed by GC and GC-MS. The content of the major constituents in the oils from leaves varied in the following ranges: germacrene D 3.7% in SFE and 16.7% in HD; ß-caryophyllene 19.1% in SFE and 13.5% in HD. The amount of monoterpenes constituted 4%, in all the analysed samples, while the number of sesquiterpenes was 44% in supercritical and 67% in HD oil. Some compounds were not identified by GC-MS and it will require further analysis using other analytical techniques.

Furanocoumarins from Dorstenia foetida.

The linear furanocoumarins 5-(2,3-epoxy-3-methyl-butoxy)-chalepensin, 5-methoxy-3-(3-methyl-2,3-dihydroxybutyl)-psoralen-diacetate (7), 5-methoxy-3-[3-(ß-D-glucopyranosyloxy)-2-acetyloxy-3-methyl-butyl]-psoralen and 5-(3-methyl-2,3-dihydroxybutyloxy)-3-[3-(ß-D-glucopyranosyloxy)-2-hydroxy-3-methyl-butyl]-psoralen, and the coumarin derivative 7-hydroxy-5-methoxy-6-carboxymethyl-3-[3-(ß-D-glucopyranosyloxy)-2-hydroxy-3-methyl-butyl]-coumarin were isolated from the leaves of Dorstenia foetida (Moraceae) along with the known compounds psoralen, bergapten, isopimpinellin, phellopterin, 5-methoxychalepensin and turbinatocoumarin. Further furanocoumarins were characterized by ESI-MS/MS investigations. The nonpolar extracts of D. foetida exhibit antifungal, antibacterial and cytotoxic activity, however, no anthelminthic activity.

Essential oil composition of leaves of Stachys yemenensis obtained by supercritical CO2.

This article reports the composition of the essential oil from the leaves of Stachys yemenensis. The essential oil was extracted by supercritical CO2 (90 bar; 40 °C) and its chemical composition was determined by gas chromatography and gas chromatography-mass spectrometry. The major components of the sample were α-phellandrene (13.9%), ß-phellandrene (11.7%), elemol (12.0%), spathulenol (6.7%), ß-eudesmol (5.0%), α-eudesmol (4.75%) and squalene (4.8%). On the exhausted matrix, deprived of the volatiles, we carried out a high-pressure (250 bar) treatment for the extraction of squalene (49.7%). The antimicrobial activity of the essential oils has been assayed by using the broth dilution method on two American Type Culture Collection (ATCC) strains, Escherichia coli ATCC 35218 and Staphylococcus aureus ATCC 43300, and two clinical strains, Candida albicans and Candida glabrata.

Screening of traditionally used endemic Soqotraen plants for cytotoxic activity.

Thirty extracts obtained from 10 endemic plant species belonging to 8 plant families used in the traditional medicine in Socotra have been tested for cytotoxic activity against FL-cells. Extracts of Eureiandra balfourii and Commiphora ornifolia showed the strongest activity against FL-cells with IC(50) < 10 microg/ml and 39.3 microg/ml respectively.