New 21-nordammarane saponins with anti-inflammatory and cytotoxic activities from Lavigeria macrocarpa Oliv.

Chemical investigation of the ethanol extract from the stems and roots of the medicinal plant Lavigeria macrocarpa led to the isolation and structure elucidation of three previously unreported 21-nordammarane-type saponins namely 6α,27-dihydroxy-3,20-dioxo-21-nordammar-24-(Z)-ene 27-O-[α-L-rhamnopyranosyl-(1→2)-ß-D-glucopyranoside] (1), 6α,27-dihydroxy-3-oxo-21-nordammar-24-(Z)-ene 27-O-ß-D-glucopyranoside (2), and 2α,3ß,6α,27-tetrahydroxy-21-nordammar-24-(Z)-ene 27-O-ß-D-glucopyranoside (3) trivially named lavigemacrocarposide A-C, along with eight known secondary metabolites. Acid hydrolysis of lavigemacrocarposide A yielded a new prosapogenin namely 6α,27-dihydroxy-3,20-dioxo-21-nordammar-24-(Z)-ene 27-O-ß-D-glucopyranoside (1a) and the previously unreported artefactual aglycones 1b and 1c. Their structures were elucidated by spectroscopic analyses including mass spectrometry, 1D and 2D NMR as well as chemical evidence. The EtOH extract, some isolated compounds as well as the prosapogenin (1a) and compounds 1b and 1c were evaluated for anti-inflammatory and cytotoxic activity. Icacine (5) exhibited a significant cytotoxicity against both HeLa and MCF-7 cell lines with an IC50 value of 0.78 µg/mL. All the tested compounds showed more that 50% inhibition of NO production, except for 1 and 2.

Siamoside A: a new C-glycosylated flavone from Senna siamea (Lam.) H. S. Irwin & Barneby (Caesalpiniaceae).

Phytochemical investigation of the methanol extracts from the leaves and bark of Senna siamea resulted in the isolation of one new flavone C-glycoside: apigenin-8-C-[6''-(E)-feruloyl]-ß-D-glucopyranoside] (1), together with sixteen known compounds including quercetin-3-O-α-L-rhamnoside (2), vitexin (3), isovitexin (4), quercetin-3-O-ß-D-glucopyranoside (5), quercetin-3-O-ß-D-arabinopyranoside (6), quercetin (7), kaempferol (8), methyl inositol (9), sucrose (10), betulinic acid (11), vanillic acid (12), stigmastane-3ß,6α-diol (13), aurantiamide acetate (14), robinetinidol (15), catechin (16) and epicatechin (17). The structures of these compounds were established on the basis of their spectroscopic (1 D and 2 D NMR) and mass spectrometric (ESI-TOF-MS) data. The methanol extracts, fractions and some of the isolated compounds were screened for their antimicrobial properties against five microbial strains. The methanol extract and the ethyl acetate fraction from the bark showed very weak antifungal activity against C. glabrata with the same MIC value of 128 µg/mL. Compound 7 was weakly active against C. albicans with MIC of 32 µg/mL.

Enhanced Anticancer Activity of Hymenocardia acida Stem Bark Extract Loaded into PLGA Nanoparticles.

Hymenocardia acida (H. acida) is an African well-known shrub recognized for numerous medicinal properties, including its cancer management potential. The advent of nanotechnology in delivering bioactive medicinal plant extract with poor solubility has improved the drug delivery system, for a better therapeutic value of several drugs from natural origins. This study aimed to evaluate the anticancer properties of H. acida using human lung (H460), breast (MCF-7), and colon (HCT 116) cancer cell lines as well as the production, characterization, and cytotoxicity study of H. acida loaded into PLGA nanoparticles. Benchtop models of Saccharomyces cerevisiae and Raniceps ranninus were used for preliminary toxicity evaluation. Notable cytotoxic activity in benchtop models and human cancer cell lines was observed for H. acida crude extract. The PLGA nanoparticles loading H. acida had a size of about 200 nm and an association efficiency of above 60%, making them suitable to be delivered by different routes. The outcomes from this research showed that H. acida has anticancer activity as claimed from an ethnomedical point of view; however, a loss in activity was noted upon encapsulation, due to the sustained release of the drug.

A new ionone derivative from Lycium intricatum Boiss. (Solanaceae).

Lycium intricatum Boiss also called 'Awsadj' is a subshrub belonging to the Solanaceae family and producing red berries. In the present work, we report the isolation of a new compound, ((1 R,3aR,7aS)-3a,7-dimethyl-1-((E)-prop-1-en-1-yl)-1,3a,4,7a-tetrahydroisobenzofuran-5(3H)-one (1)). Three known compounds were also isolated for the first time from L. intricatum, and identified as isoscopoletin (2), 3,4,5-trimethoxybenzyl alcohol (3), and (+)-isolariciresinol (4). Compounds 1-4 were isolated from the extract of leaves using chromatographic techniques, and the structure of compound 1 was fully elucidated by NMR, MS and ECD experiments.

Alkaloids and sesquiterpenes from roots and leaves of Lycium europaeum L. (Solanaceae) with antioxidant and anti-acetylcholinesterase activities.

Lycium europaeum L. is a spiny shrub of the Solanaceae family, known in Algeria as 'Awsaj' and used as food and herbal remedy. The phytochemical investigation of the alkaloid extract of roots and leaves led to the isolation and characterisation of one alkaloid (harmine (3)) and four sesquiterpenes (C-1' epimer of (2 R,5S,10R)-2-(1',2'-dihydroxy-1'-methylethyl)-6,10-dimethylspiro[4,5]dec-6-en-8-one (1), C-1' epimer of 2-(1',2'-di-hydroxy-1'-methylethyl)-6,10-dimethylspiro[4,5]dec-6,9-dien-8-one (2), (+)-dehydrovomifoliol (4), vomifoliol (5)). Their structures were elucidated using NMR and MS spectroscopic data. The isolated compounds were characterised for the first time from the genus Lycium. All isolated compounds have shown antioxidant and acetylcholinesterase (AChE) inhibitory activities in the bioautography assays. The ethanolic and alkaloid extracts of roots and leaves were also tested, and, particularly, the alkaloid extracts were the most active ones as antioxidant and AChE inhibitors.

The volatile oils from the oleo-gum-resins of Ferula assa-foetida and Ferula gummosa: A comprehensive investigation of their insecticidal activity and eco-toxicological effects.

Since time immemorial, the oleo-gum-resins of Ferula assa-foetida and F. gummosa are used in the traditional medical systems as well as in foodstuffs, perfumery and cosmetics. In the present study, we explored the insecticidal efficacy of the essential oils obtained from these oleo-gum-resins to widen their fields of industrial applications. The two essential oils were mainly composed of sulfides [sec-butyl (Z)-propenyl disulfide, sec-butyl (E)-propenyl disulfide, sec-butyl (Z)-propenyl trisulfide and sec-butyl (E)-propenyl trisulfide)] and monoterpenes (α-pinene, ß-pinene and ß-phellandrene), respectively, as determined by GC-MS analysis. The two essential oils were assayed for toxicity on a panel of insects, represented by species of public health relevance (Culex quinquefasciatus and Musca domestica), agricultural (Spodoptera littoralis) and stored-product pests (Prostephanus truncatus and Trogoderma granarium). The ecotoxicological effects of the essential oils were assessed on the aquatic microcrustacean Daphnia magna and the earthworm Eisenia fetida, as well as on human cells. Overall, the two essential oils were effective against important insect pests and vectors. On the other hand, they resulted cytotoxic to fibroblasts and non-target aquatic microcrustaceans. Thus, further insights are needed to determine the full spectrum of their eco-toxicological effects.

Ascaridole-rich essential oil from marsh rosemary (Ledum palustre) growing in Poland exerts insecticidal activity on mosquitoes, moths and flies without serious effects on non-target organisms and human cells.

Marsh rosemary (Ledum palustre, Ericaceae) has been widely used in the traditional medicine of various regions worldwide, and as insect repellent. Little is known on its essential oil insecticidal potential. This study explored the insecticidal effects of the essential oil obtained from L. palustre growing in Poland on selected insect pests and vectors. GC-MS analysis evidenced an uncommon chemotype characterized by ascaridole (35.3% as sum of cis-ascaridole and isoascaridole) and p-cymene (25.5%). The essential oil was effective against Culex quinquefasciatus, Spodoptera littoralis and Musca domestica, showing LC50/LD50 of 66.6 mg L-1, 117.2 µg larva-1 and 61.4 µg adult-1, respectively. It was not toxic to non-target Eisenia fetida earthworms and moderately toxic to Daphnia magna microcrustaceans, over the positive control α-cypermethrin. The essential oil cytotoxicity on human keratinocytes and fibroblasts showed high IC50 values (71.3 and 84.4 µg mL-1, respectively). Comet assay data highlighted no DNA damages. Based on our findings, this essential oil, characterized by the ascaridole/p-cymene chemotype, could be a candidate for the formulation of botanical insecticides; large-scale production of green insecticides by this rare species may be assured by ex situ cultivation and biotechnological techniques.

Steroidal saponins from the aerial parts of Cordyline fruticosa L. var. strawberries.

A new sulfated steroidal derivative (fruticogenin A: 1-sulfo-australigenin-3-sodium sulphate, 1) and three new steroidal saponins named fruticoside K (3-sulfo-spirostan-25(27)-ene-1ß,3ß-diol-1-O-[α-L-rhamnopyranosyl-(1 → 4)-ß-D-fucopyranoside], 2), fruticoside L (3-sulfo-spirostan-25(27)-ene-1ß,3ß,6α-triol-1-O-[α-L-rhamnopyranosyl-(1 → 4)-ß-D-fucopyranoside], 3) and fruticoside M (spirostan-25(27)-ene-1ß,3α-diol-1-O-[α-L-rhamnopyranosyl-(1 → 2)-α-L-rhamnopyranoside], 4) were isolated from the aerial parts of Cordyline fruticosa L. var. strawberries. Their structures were established on the basis of 1D and 2D NMR data, mass spectrometry and chemical methods. Compounds 2 and 4 exhibited weak cytotoxicity against melanoma (A375), breast adenocarcinoma (MDA-MB-231), and colon carcinoma (HCT116) human tumor cell lines.

Clausena anisata and Dysphania ambrosioides essential oils: from ethno-medicine to modern uses as effective insecticides.

Dysphania ambrosioides (L.) Mosyakin & Clemants (Amaranthaceae) and Clausena anisata (Willd.) Hook. f. ex Benth. (Rutaceae) are two aromatic species traditionally used in Cameroon to repel and kill insects. The present work was carried out to substantiate this traditional use and to evaluate the possible incorporation in commercial botanical insecticides of their essential oils (EOs). The EOs were distilled from leaves of C. anisata and aerial parts of D. ambrosioides and analyzed by gas chromatography-mass spectrometry (GC-MS). The insecticidal activity of both EOs was investigated against the filariasis vector, Culex quinquefasciatus, and the housefly, Musca domestica. As possible mode of action, the inhibition of acetylcholinesterase (AChE) by the two EOs was investigated as well. The D. ambrosioides EO was characterized by the monoterpene peroxide ascaridole (61.4%) and the aromatic p-cymene (29.0%), whereas the C. anisata EO was dominated by the phenylpropanoids (E)-anethole (64.6%) and (E)-methyl isoeugenol (16.1%). The C. anisata EO proved to be very toxic to third instar larvae of C. quinquefasciatus showing LC50 of 29.3 µl/l, whereas D. ambrosioides EO was more toxic to adults of M. domestica showing a LD50 of 51.7 µg/adult. The mixture of both EOs showed a significant synergistic effect against mosquito larvae with LC50 estimated as 19.3 µl/l, whereas this phenomenon was not observed upon application to M. domestica adults (LD50 = 75.9 µg/adult). Of the two EOs, the D. ambrosioides one provided a good inhibition of AChE (IC50 = 77 µg/ml), whereas C. anisata oil was not effective. These findings provide new evidences supporting the ethno-botanical use of these two Cameroonian plants, and their possible application even in synergistic binary blends, to develop new eco-friendly, safe and effective herbal insecticides.

Trypanosoma brucei Inhibition by Essential Oils from Medicinal and Aromatic Plants Traditionally Used in Cameroon (Azadirachta indica, Aframomum melegueta, Aframomum daniellii, Clausena anisata, Dichrostachys cinerea and Echinops giganteus).

Essential oils are complex mixtures of volatile components produced by the plant secondary metabolism and consist mainly of monoterpenes and sesquiterpenes and, to a minor extent, of aromatic and aliphatic compounds. They are exploited in several fields such as perfumery, food, pharmaceutics, and cosmetics. Essential oils have long-standing uses in the treatment of infectious diseases and parasitosis in humans and animals. In this regard, their therapeutic potential against human African trypanosomiasis (HAT) has not been fully explored. In the present work, we have selected six medicinal and aromatic plants (Azadirachta indica, Aframomum melegueta, Aframomum daniellii, Clausena anisata, Dichrostachys cinerea, and Echinops giganteus) traditionally used in Cameroon to treat several disorders, including infections and parasitic diseases, and evaluated the activity of their essential oils against Trypanosma brucei TC221. Their selectivity was also determined with Balb/3T3 (mouse embryonic fibroblast cell line) cells as a reference. The results showed that the essential oils from A. indica, A. daniellii, and E. giganteus were the most active ones, with half maximal inhibitory concentration (IC50) values of 15.21, 7.65, and 10.50 µg/mL, respectively. These essential oils were characterized by different chemical compounds such as sesquiterpene hydrocarbons, monoterpene hydrocarbons, and oxygenated sesquiterpenes. Some of their main components were assayed as well on T. brucei TC221, and their effects were linked to those of essential oils.

Stabilization of the cyclodecadiene derivative isofuranodiene by silver (I) coordination. Mechanistic and biological aspects.

The industrial extraction and further applications of isofuranodiene are limited because at room temperature it spontaneously converts to curzerene, a structurally less active isomer. This work definitively identified the structure of isofuranodiene in the solid state, showing the two methyl groups in syn position. In addition, two bioactive metal cations, namely, silver(I) and copper(II) ions, were used in the attempt to obtain the chemical stability of isofuranodiene: in the case of silver(I), a labile adduct was formed, while in the case of copper(II), a more stable 1:1 adduct was achieved. In the former, the presence of silver did not significantly affect the biological activities of isofuranodiene, while in the latter, the copper(II) coordination suppressed them. The biological activities of the isofuranodiene adducts were then evaluated as antiproliferative agents against human tumor cell lines (HCT116, MDA-MB 231, and T98G). In addition, for the first time, isofuranodiene was tested as an inhibitor of DHFR (DiHydroFolateReductase) from Escherichia coli. Anticancer activity was observed in the isofuranodiene with the AgCF3SO3 adduct, in the tested cell lines, with IC50 values ranging from 4.89µM to 13.06µM, while inhibition assays highlighted a Ki of 6.22µM for isofuranodiene and of 0.17µM for the related silver adduct. Docking studies indicated a binding mode score of -6.83Kcal/mol for isofuranodiene, and an energy value of -11.82Kcal/mol for methotrexate (a classic DHFR inhibitor).

Traditional herbal remedies and dietary spices from Cameroon as novel sources of larvicides against filariasis mosquitoes?

In Cameroon, many dietary spices are used by traditional healers to cure several diseases such as cancer and microbial infections. Aframomum daniellii, Dichrostachys cinerea and Echinops giganteus are Cameroonian spices widely used as flavourings and as food additives. Moreover, they are traditionally herbal remedies employed to treat several diseases, as well as to control populations of insect pests. In this research, we analysed the chemical composition of A. daniellii, D. cinerea and E. giganteus essential oils and we evaluated their larvicidal potential against larvae of the filariasis and West Nile virus vector Culex quinquefasciatus. The essential oils were obtained from different plant parts by hydrodistillation and their composition was analysed by GC-MS. The three spices exhibited different volatile chemical profiles, being characterized by 1,8-cineole, sabinene and ß-pinene (A. daniellii), geraniol and terpinen-4-ol (D. cinerea), and silphiperfol-6-ene and presilphiperfolan-8-ol (E. giganteus). Results showed that the highest larvicidal toxicity on Cx. quinquefasciatus was exerted by D. cinerea essential oil (LC50 = 39.1 µL L-1), followed by A. daniellii (pericarp essential oil: LC50 = 65.5 µL L-1; leaves: LC50 = 65.5µL L-1; seeds: LC50 = 106.5µL L-1) and E. giganteus (LC50 = 227.4 µL L-1). Overall, the chance to use the D. cinerea essential oil against Cx. quinquefasciatus young instars seems promising, since it is effective at moderate doses and could be an advantageous alternative to build newer mosquito control tools.

Antioxidant C-glycosylflavones of Drymaria cordata (Linn.) Willd.

A new C-glycosylflavone, drymaritin E (6-C-(3-keto-ß-digitoxopyranosyl)-4'-O-(ß-D-glucopyranosyl)-7-methoxyl-5,4'-dihydroxylflavone) 1 was isolated from the oily upper phase (SU) of the MeOH extract from aerial parts of Drymaria cordata together with two known compounds (cassiaoccidentalin A 2 and anemonin 3) and an inseparable mixture of two known C-glycosylflavones 5,4'-dihydroxy-7-methoxyflavone-6-C-(2''-O-α-L-rhamnopyranosyl)-ß-D-glucopyranoside 4a and 5,7,3',4'-tetrahydroxyflavone-6-C-(2''-O-α-L-rhamnopyranosyl)-ß-D-glucopyranoside 4b. The alkaline hydrolysis of 3 led to a new hemisynthetic derivative, sodium anemonate (sodium 2-((1'E) 2'-sodium-carboxylate-vinyl)-5-oxo-cyclohex-1-ene carboxylate) 3a. The chemical structures were determined by spectroscopic methods ((1)H NMR, (13)C NMR, (1)H-(1)H COSY, HMBC, HSQC, and NOESY) and mass spectrometry (ESI-MS). C-glycosylflavones had significant free radical-scavenging activities on the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). However, SU and compounds 3 and 3a exhibited no activity. In particular, compound 1 exhibited a concentration-dependent radical scavenging activity on DPPH with EC50 of 31.43 µg/mL.

Wild celery (Smyrnium olusatrum L.) oil and isofuranodiene induce apoptosis in human colon carcinoma cells.

Smyrnium olusatrum (Apiaceae), well known as wild celery, is a biennal celery-scented plant used for many centuries as a vegetable, then abandoned after the introduction of celery. In the present work, the essential oil obtained from inflorescences and the amounts of its main constituents isofuranodiene, curzerene and germacrone were analyzed by GC as well as by HPLC because of their degradation (Cope rearrangement) occurring at high temperatures. The oil and the main constituents were assayed for cytotoxic activity on the human colon cancer cell line (HCT116) by MTT assay. Flower oil and isofuranodiene showed noteworthy activity on tumor cells with IC50 of 10.71 and 15.06 µg/ml, respectively. Analysis of the cytotoxic activity showed that wild celery oil and isofuranodiene are able to induce apoptosis in colon cancer cells in a time and concentration-dependent manner suggesting a potential role as models for the development of chemopreventive agents.

In vitro biological activities of seed essential oils from the Cameroonian spices Afrostyrax lepidophyllus MILDBR. and Scorodophloeus zenkeri HARMS rich in sulfur-containing compounds.

The chemical composition of the essential oils obtained from the seeds of bush onion (Afrostyrax lepidophyllus) and tropical garlic tree (Scorodophloeus zenkeri), plants used as spices in the traditional African cuisine, was determined by GC-FID and GC/MS analyses. Moreover, in vitro biological properties of the oils, namely, the cytotoxic, antioxidant, and antimicrobial activities, were investigated by the MTT, the DPPH(.) and ABTS(.+) scavenging, and the agar disc-diffusion methods, respectively. Both oils were composed mainly by S-containing compounds, accounting for 91.0-96.1% of the total oil compositions, which provided them the typical garlic- and onion-like odors of spices. The predominant compound in both oils, 2,4,5,7-tetrathiaoctane (1; 51.5-52.9%), was isolated by preparative TLC and structurally elucidated by (1) H- and (13) C-NMR data. The oils exhibited a strong inhibitory effect on the growth of human cancer cells, namely, T98G (human glioblastoma multiforme cell line), MDA-MB 231 (human breast adenocarcinoma cell line), A375 (human malignant melanoma cell line), and HCT116 (human colon carcinoma cell line) cells, and a good DPPH(.) - and ABTS(.+) -scavenging activity, while the antimicrobial effects were negligible. The volatile compositions of A. lepidophyllus and S. zenkeri oils supported their use as odorous spices. The significant inhibition activities detected make these oils worthy of further investigation as promising chemopreventive agents to be exploited in the African pharmaceutical market.

Volatile oil from striped African pepper (Xylopia parviflora, Annonaceae) possesses notable chemopreventive, anti-inflammatory and antimicrobial potential.

Fruits of Xylopia parviflora, well known as striped African pepper, are sold in the Cameroonian markets as a flavouring ingredient to make traditional soups. The essential oil hydrodistilled from fruits was analysed for in vitro biological activities, namely cytotoxic, anti-inflammatory, antimicrobial and antioxidant, by MTT, nitric oxide inhibitory assay, agar disc diffusion method, and DPPH and ABTS assays. The essential oil composition, analysed by GC and GC-MS, was dominated by monoterpene hydrocarbons (50.0%) responsible for the pepper odour, such as ß-pinene (34.0%) and α-pinene (10.3%). The oil induced a strong inhibitory effect on tumour cells MDA-MB 231 and HCT116, with inhibition values close to those of cisplatin. A dose-dependent decrease in NO production was noted in RAW 264.7 macrophages treated with the oil, revealing a promising anti-inflammatory potential. The essential oil showed a measurable antimicrobial activity against all the species tested, while the radical scavenging activity was low.

In vitro biological activity of essential oils and isolated furanosesquiterpenes from the neglected vegetable Smyrnium olusatrum L. (Apiaceae).

Smyrnium olusatrum, better known as Alexanders or wild celery, is a biennal herb used in cuisine for many centuries by Romans in many dishes, where it has now been replaced by celery. In order to provide additional evidences so that this forgotten vegetable can be reconsidered in the human diet, as well as in pharmaceutics, the essential oils obtained from different parts and its main isolated furanosesquiterpenes were in vitro biologically assayed for antiproliferative activity on human tumor cell lines by MTT assay, for antioxidant potential by DPPH, ABTS and FRAP assays, and for antimicrobial activity by the agar disc diffusion method. The essential oils showed cytotoxic effects on tested human tumor cell lines, related to the furanosesquiterpenoid content; the IC(50) values on colon carcinoma, glioblastoma, and breast adenocarcinoma cells were 8.51, 13.35, and 14.81 µg/ml, respectively. Isofuranodiene and 1ß-acetoxyfuranoeudesm-4(15)-ene resulted the most active constituents. The essential oils possessed also radical scavenging activity.

Antioxidant, antiproliferative and antimicrobial activities of the volatile oil from the wild pepper Piper capense used in Cameroon as a culinary spice.

Wild pepper (Piper capense L.f., Piperaceae) is a spice traditionally used in western Cameroon to make soups called 'Nkui' and 'Nah poh'. In the present work, the essential oil hydrodistilled from fruits was analyzed by GC-FID and GC-MS, and for in vitro biological activities, namely cytotoxic, antioxidant and antimicrobial, by MTT, DPPH, ABTS and agar disc diffusion methods. The oil composition was dominated by monoterpene hydrocarbons (56.5%) responsible for the pepper odor, such as (beta-pinene (33.2%), sabinene (10.0%) and alpha-pinene (8.9%). The oil induced a concentration-dependent inhibitory effect on human tumor cells MDA-MB 231 (breast adenocarcinoma), A375 (malignant melanoma) and HCT116 (colon carcinoma), showing IC50 values of 26.3, 76.0 and 22.7 microg/ml, respectively. The oil showed total antioxidant activity with a Trolox equivalent antioxidant concentration (TEAC) value of 140 micromol/g. The essential oil of P. capense proved to be an effective scavenger of the ABTS+ radical, with an activity only about 30 times lower than that of Trolox. Moderate activity was observed against the Gram-positive species Staphylococcos aureus and Enterococcusfaecalis, and the yeast Candida albicans. The notable inhibition of some human tumor cells is worthy of further investigation to discover the possible mechanisms of action responsible for the observed cytotoxic effect of this essential oil.

Antibacterial activities of the extracts, fractions and compounds from Dioscorea bulbifera.

BACKGROUND: Dioscorea bulbifera is an African medicinal plant used to treat microbial infections. In the present study, the methanol extract, fractions (DBB1 and DBB2) and six compounds isolated from the bulbils of D. bulbifera, namely bafoudiosbulbins A (1), B (2), C (3), F (4), G (5) and 2,7-dihydroxy-4-methoxyphenanthrene (6), were tested for their antimicrobial activities against Mycobacteria and Gram-negative bacteria involving multidrug resistant (MDR) phenotypes expressing active efflux pumps. METHODS: The microplate alamar blue assay (MABA) and the broth microdilution methods were used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the above samples. RESULTS: The results of the MIC determinations indicated that when tested alone, the crude extract, fractions DBB1 and DBB2 as well as compounds 2 to 5 were able to prevent the growth of all the fifteen studied microorganisms, within the concentration range of 8 to 256 µg/mL. The lowest MIC value for the methanol extract and fractions (16 µg/mL) was obtained with DBB1 and DBB2 on E, coli AG100A and DBB2 on Mycobacterium tuberculosis MTCS2. The lowest value for individual compounds (8 µg/mL) was recorded with compound 3 on M. smegmatis and M. tuberculosis ATCC and MTCS2 strains respectively. The activity of the samples on many MDR bacteria such as Enterobacter aerogenes EA289, CM64, Klebsiella pneumoniae KP63 and Pseudomonas aeruginosa PA124 was better than that of chloramphenicol. When tested in the presence of the efflux pump inhibitor against MDR Gram-negative bacteria, the activity of most of the samples increased. MBC values not greater than 512 µg/mL were recorded on all studied microorganisms with fraction DBB2 and compounds 2 to 5. CONCLUSIONS: The overall results of the present investigation provided evidence that the crude extract D. bulbifera as well as some of the compounds and mostly compounds 3 could be considered as potential antimicrobial drugs to fight against MDR bacteria.

A forgotten vegetable (Smyrnium olusatrum L., Apiaceae) as a rich source of isofuranodiene.

Smyrnium olusatrum, well known as wild celery or Alexanders, is a biennial herb belonging to the Apiaceae and used for many centuries as an edible vegetable because of the aromatic flavour of its parts. Its use on the table has decreased since the Middle Ages when it was replaced by common celery (Apium graveolens). In the present work the composition of the essential oils obtained by hydrodistillation of various plant parts was investigated by gas chromatography (GC-FID and GC-MS), while quantitation of a heat-sensitive compound, isofuranodiene, known for its anticancer activity, and of its Cope rearrangement product curzerene, was achieved by HPLC-DAD. All essential oils were composed mainly of furanosesquiterpenoids (54.1-76.2%) with isofuranodiene (19.5-45.8%) as the main constituent. Results showed that GC analysis provides underestimation (up to five times) of isofuranodiene levels in essential oils and that curzerene could be considered an artifact since it is produced during heating of plant material, occurring during hydrodistillation.