In Vitro Anti-inflammatory Activity of Three Inula Species Essential Oils in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages

In the face of the undesirable effects induced by anti-inflammatory drugs, there has been a return, nowadays, to the search for active ingredients based on plants. Herein, for the first time we study the anti-inflammatory activity of essential oils of three species of the genus Inula: Inula viscosa, Inula graveolens and Inula crithmoides in lipopolysaccharide (LPS)-activated macrophages. Essential oils have shown excellent preventive anti-inflammatory potential by causing inhibition of nitric oxide (NO) production in LPSactivated RAW264.7 macrophages with IC50s ranging between 15 and 35 µg  mL^− 1. On the other hand, the major acidic compounds, more precisely α- and β-costic acids, have been isolated from Inula viscosa and Inula graveolens essential oils and evaluated for their anti-inflammatory effect. These compounds appear to have a moderate preventive inhibitory effect on NO production relative to the significant effect generated by the neutral minority components present in the oils such as borneol, bornyl acetate, (E)-nerolidol, caryophyllene oxide, T-cadinol and eugenol. Therefore, we can deduce that the studied essential oils could be used as anti-inflammatory agents for the treatment of various inflammatory pathologies.

<i>d</i>-Limonene challenging anti-inflammatory strategies

<abstract> <p>Aging and senescence seem linked by fundamental, yet still ill-understood mechanisms. For this reason, this paper expands on the background of a discovery that still has to gain acknowledgement by public policies to find its place in a market hungry for a non-toxic anti-inflammatory molecule. Reversibility of the senescent cell phenotype was the starting-point of a research that turned out to identify the monoterpenes class of molecules as able to achieve this goal. Indeed, these compounds strongly inhibit the circulation of pro-inflammatory cytokines as well as the expression of cell-anchored adhesive molecules, liable to recruit activated immune cells. Starting from cell-based studies, the pre-clinical and clinical assays reported here confirmed the capacities of these compounds, both in experimental colitis, dermatitis and stress murine models, but also in-human studies addressing the latent chronic inflammation associated with age or psoriasis. Last but not least, because of an intriguing mechanism yet not totally unraveled and most probably depending on the effect of monoterpenes on gut microbiota strains–apart from assuring a constant gut barrier repair-a consistent Quality of Life amelioration, i.e. mood modulation probably due to enhanced dopamine secretion was also demonstrated. Finally, after entering in more pharmacologic considerations on toxicity and bio-availability studies as for the safety of this class of compounds, a strategic positioning of the precious role of anti-inflammatory drugs in a market that has yet to overcome common chronic diseases because of their predisposing condition not only to cancer and neuro-degenerative diseases but now also to COVID-19 is envisioned.</p> </abstract>

Chemical Composition, Antiradical and Antifungal Activities of Essential Oil of the Leaves of Cinnamomum Zeylanicum Blume from Cameroon

The aim of the present study was to investigate the essential oil of Cinnamomum zeylanicum from Cameroon for its chemical composition, antiradical and antifungal activities against some common fungi causing spoilage of stored food product. The essential oil, obtained by hydrodistillation of fresh leaves, was analysed by GC and GC/MS. The oil contains 11 components among which eugenol (89.1%), linalool (4.3%), benzoate benzyl (3.1%) and cinnamaldehyde (1.5%) were the main components. Determination of antiradical activity of the oil was studied by the DPPH (diphenyl picryl hydrazyl) method. The antiradical activity of Cinnamomum essential oil (SC50 = 4.5 mg/L) was higher than that of butylated hydroxy toluene (BHT), which was used as the reference compound (SC50 = 7 mg/L). The growth inhibitory effect of C. zeylanicumn essential oil on Aspergillus flavus and Fusarium moniliforme was determined on potato dextrose agar. After 9 days of incubation on essential oil-supplemented medium, the growth of A. flavus and Fusarium was totally inhibited by 500 ppm of Cinnamommum zeylanicum oil. Results obtained in the present study indicate the possibility of exploiting C. zeylanicum essential oil to prevent diseases such as diabetes and cancer, to slow down ageing, and also to combat strains of A. flavus and Fusarium moniliforme responsible for biodeterioration of stored food products.

Mangifera indica Bark Essential Oil: Chemical Composition and Biological Activities in Comparison with Aqueous and Ethanol Extracts

Ethnobotanic surveys have revealed the use of Mangifera indica L. (Anacardiaceae) bark for the treatment of infectious diarrhea. The essential oil of M. indica bark is described for the first time for its chemical composition, radical scavenging activity (DPPH method) and antimicrobial properties. The total phenols content of its water and ethanol bark extracts as well as their radical scavenging and antimicrobial properties were also evaluated. Four commercial plant extracts were also studied for a comparison purpose. The antimicrobial activities were measured for all samples against three Gram (-): Escherichia coli, Salmonella enteritidis, Shigella and two Gram (+): Staphylococcus aureus and Bacillus cereus bacteria. The M. indica bark essential oil was characterized by the association of two major sesquiterpenes: ( E)-β-caryophyllene (60.3%) and α-humulene (36.7%). It presented the lowest ratio of concentration to inhibition zone diameter on all the strains. The aqueous and ethanol extracts of M. indica bark were characterized by high contents of total phenols compounds and high radical scavenging activity compared to the essential oil. Finally, the interesting combination of the antibacterial and antiradical activities of the aqueous M. indica bark extract justifies the traditional use of this plant part in decoction form for the treatment of diarrheal infections.

Influence of geography, seasons and pedology on chemical composition and anti-inflammatory activities of essential oils from Lippia multiflora Mold leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Lippia multiflora is a plant with nutritional and pharmaco-therapeutic properties that is native to central and occidental Africa. The potential effects of plants on health are associated with their chemical composition. Therefore, the present study aimed to identify chemical variations in essential oils of Lippia multiflora as a function of geographic origin and time of annual harvest to determine optimal chemical profiles for ethno-pharmacotherapeutic applications.

MATERIALS AND METHODS

Experimental plants were cultivated at Abidjan (LPA), Toumodi (LPT) and Bondoukou (LPB). Natural Lippia multiflora seeds were sourced to produce standardized plants over a period of six months. Standard plants (n=40) were re-introduced into natural plots, cultivated for 12 months and leaves were sampled monthly in a standardized fashion. Essentials oils (n=36) were then extracted from these samples by hydro-distillation according to the European Pharmacopoeia and qualitatively and quantitatively analyzed using GC/FID and GC/MS. These data were then analyzed using Principal Component Analysis (PCA). Anti-inflammatory properties were also assessed against activated macrophages in vitro.

RESULTS

The results indicated that chemical profiles and essential oil yields vary according to the location where the plants were cultivated. One essential oil chemotype corresponded to the LPA and LPT sites and one corresponded to the LPB site. Statistical analysis of the chemical profiles and monthly evolution of the three sites over a period of one year allowed assessment of variations in composition and the subsequent choice of the optimal harvest time for ethnopharmacological applications. Anti-inflammatory activity apparently correlated with chemical profiles of essential oils and the geographic origins of the plants.

CONCLUSION

The optimal harvest time was associated with the maximum yield of pharmacological compounds with the most potential interest for health.

Antidiabetic potential of two medicinal plants used in Gabonese folk medicine

BACKGROUND

Diabetes mellitus is a metabolic disorder which is rising globally in rich and developing countries. In the African region this rate is the highest, with 20 million diagnosed diabetics. Despite a noticeable progress in the treatment of diabetes mellitus by synthetic drugs, the search for new natural anti-diabetic agents is going on. Nauclea diderrichii (De Wild.) Merr. (ND) and Sarcocephalus pobeguinii Hua ex Pellegr. (SP) are used as traditional medicines in Gabon for the treatment of different diseases, especially in the case of diabetes. The aim of this study was to evaluate the antidiabetic potential of these two medicinal plants traditionally used in Gabon.

METHODS

Pharmacological (inhibitory action on α and β-glucosidases) and toxicological (effect on human T cell proliferation) studies were conducted on aqueous extracts of ND (leaves and bark) and SP (bark) collected in Gabon. All raw extracts were analyzed by HPTLC and their content in phenolic compounds was determined by using standard method. The most active extracts were submitted to preparative HPLC in order to evidence the most efficient subfractions by biological evaluation.

RESULTS

The results showed that two extracts from ND were potent α-glucosidase inhibitors, the leaf extract being more active that the bark extract: the first one was more than 60 fold more active than Acarbose, which is an oral medication used to treat type 2 diabetes; the extract from SP bark was less efficient. The HPLC subfractions of the extracts of ND leaves and SP bark were tested in the same experimental conditions. In each case, the most active subfractions still show very potent inhibitory effect on α-glucosidase (80-90% inhibition at 0.1 mg/mL). The most efficient extract, from ND leaves, was also characterized by the highest percentage of phenolic compounds, which suggests a relationship between its inhibitory potential on α-glucosidase and its content in phenolic compounds. Conversely, only a moderate inhibitory activity of the three extracts was observed on β-glucosidase.

CONCLUSION

These results clearly indicated that active compounds present in N. diderrichii and S. pobeguinii leaves or/and bark were selective and highly potent inhibitors of α-glucosidase and validate their popular use for the treatment of diabetes.

Naturally occurring bioactive compounds from four repellent essential oils against Bemisia tabaci whiteflies

BACKGROUND

In tropical countries, netting is an effective sustainable tool for protecting horticultural crops against Lepidoptera, although not against small pests such as Bemisia tabaci, while smaller mesh netting can be used in temperate regions. A solution is to combine a net with a repellent. Previously we identified repellent essential oils: lemongrass (Cymbopogon citratus), cinnamon (Cinnamomum zeylanicum), cumin (Cuminum cyminum) and citronella (Cymbopogon winternarius). The present study was designed to identify the active compounds of these essential oils, characterise their biological activity and examine their potential for coating nets. We investigated the efficiency and toxicity of nets dipped in different solutions. We then studied the repellent effect with an olfactometer and the irritant effect by videotracking.

RESULTS

Geraniol and citronellol were the most promising net coatings owing to their repellent effect. The repellency, irritancy or toxicity varied with the product and concentration, and these features were independent, indicating that the repellent and the irritant/toxic mechanisms were not the same. The combined effects of these different compounds account for the bioactivity of the mixture, suggesting interactions between the compounds.

CONCLUSION

This new sustainable strategy for protecting vegetable crops against whiteflies is discussed, in addition to the use of companion plants that could produce such bioactive compounds.

Chemical Diversity of Podocarpaceae in New Caledonia: Essential Oils from Leaves of Dacrydium, Falcatifolium, and Acmopyle Species

Plant secondary metabolites can be useful chemosystematic markers to distinguish species at different taxonomy levels. For example, sesquiterpenes and diterpenes show specific distribution patterns within conifers and so provide especially precious information about the diversity and evolutionary relationships of this group. The aim of the present study was to provide a first insight into the terpene diversity of endemic Podocarpaceae from New Caledonia. The leaf essential oils of Dacrydium araucarioides Brongn. & Gris, Dacrydium balansae Brongn. & Gris, Dacrydium guillauminii J.Buchholz, Dacrydium lycopodioides Brongn. & Gris, Falcatifolium taxoides (Brongn. & Gris) de Laub., and Acmopyle pancheri (Brongn. & Gris) Pilg. from New Caledonia were characterized by GC/FID and GC/MS analyses, and the chemotaxonomic relationships of these species were determined by comparison of their terpene compositions. Cluster analysis based on the biosynthetic origin of their volatile terpenes led to the description of three distinct groups of essential oils and showed close relationships between those of D. araucarioides and D. balansae as well as between those of A. pancheri and F. taxoides.

Behavioral Response of Bemisia tabaci (Hemiptera: Aleyrodidae) to 20 Plant Extracts

In the Mediterranean region, the use of small-mesh netting to protect horticultural crops is an effective sustainable tool against pests. But in tropical regions, because of high humidity under the net favoring fungal development, netting with a larger mesh size has to be used, protecting crops against lepidopteran pests but not against small pests such as hemipterans, thrips, and phytophagous mites. A combination of netting with a repellent or irritant product is one possible solution, but the desire to reduce the use of synthetic chemicals and mitigate resistance issues calls for a natural alternative. The objective of this study was to evaluate the repellent, irritant, and toxic effects of nets dipped in 20 different plant extracts on Bemisia tabaci (Gennadius) adults. The repellent effect of volatile compounds was evaluated using a still-air olfactometer. The irritant effect and toxicity were evaluated with a no-choice test in tubes separated into two parts by an impregnated net. Our results showed the seven most irritant and toxic products against B. tabaci were aframomum, cinnamon, geranium, dill, citronella, litsea, and savory. The most repellent were aframomum and lemongrass, although cinnamon, geranium, and savory were also repellent at higher doses. Effects varied with the plant extract and the concentration, and effects were independent of one another, i.e., an essential oil can be irritant but not repellent, suggesting that the repellent mechanism and that behind the irritant or toxic effects is not the same. The use of repellent compounds in combination with netting as new pest control strategy is discussed.

Electrophysiological and behavioral characterization of bioactive compounds of the Thymus vulgaris, Cymbopogon winterianus, Cuminum cyminum and Cinnamomum zeylanicum essential oils against Anopheles gambiae and prospects for their use as bednet treatments

BACKGROUND

Laboratory and field studies showed that repellent, irritant and toxic actions of common public health insecticides reduce human-vector contact and thereby interrupt disease transmission. One of the more effective strategies to reduce disease risk involves the use of long-lasting treated bednets. However, development of insecticide resistance in mosquito populations makes it imperative to find alternatives to these insecticides. Our previous study identified four essential oils as alternatives to pyrethroids: Thymus vulgaris, Cymbopogon winterianus, Cuminum cyminum, Cinnamomum zeylanicum. The objectives of this study were to identify active compounds of these essential oils, to characterize their biological activity, and to examine their potential as a treatment for bednets.

METHODS

We evaluated the electrophysiological, behavioural (repellency, irritancy) and toxic effects of the major compounds of these oils against Anopheles gambiae strain 'Kisumu'.

RESULTS

Aldehydes elicited the strongest responses and monoterpenes the weakest responses in electroantennogram (EAG) trials. However, EAG responses did not correlate consistently with results of behavioral assays. In behavioral and toxicity studies, several of the single compounds did exhibit repellency, irritancy or toxicity in An. gambiae; however, the activity of essential oils did not always correlate with activity expected from the major components. On the contrary, the biological activity of essential oils appeared complex, suggesting interactions between individual compounds and the insect under study. Data also indicated that the three effects appeared independent, suggesting that repellency mechanism(s) may differ from mechanisms of irritancy and toxicity.

CONCLUSIONS

Based on the bioassays reported here, some of the compounds merit consideration as alternative bednet treatments.

Composition and cytotoxic activity of essential oils from Xylopia aethiopica (Dunal) A. Rich, Xylopia parviflora (A. Rich) Benth.) and Monodora myristica (Gaertn) growing in Chad and Cameroon

Background

Cancer has become a global public health problem and the search for new control measures is urgent. Investigation of plant products such as essential oils from Monodora myristica, Xylopia aethiopica and Xylopia parviflora might lead to new anticancer therapy. In this study, we have investigated the antineoplastic activity of essential oils from fruits of these plants growing in Chad and Cameroon.

Methods

The essential oils obtained by hydrodistillation of fruits of Monodora myristica, Xylopia aethiopica and Xylopia parviflora collected in Chad and Cameroon were analyzed by GC-FID and GC-MS and investigated for their antiproliferative activity against the breast cancer cell line (MCF7).

Results

Overall, monoterpenes were mostly found in the six essential oils. Oils from X. aethiopica and X. parviflora from Chad and Cameroon mainly contain β-pinene at 24.6%, 28.2%, 35.7% and 32.9% respectively. Monodora myristica oils from both origins contain mainly α-phellandrene at 52.7% and 67.1% respectively. The plant origin did not significantly influence the chemical composition of oils. The six essential oils exerted cytotoxic activity against cancer (MCF-7) and normal cell lines (ARPE-19), with more pronounced effect on neoplastic cells in the majority of cases. The highest selectivity was obtained with the essential oils of X. parviflora from Chad and Cameroon (5.87 and 5.54) which were more cytotoxic against MCF-7 than against normal cell line (ARPE-19) with IC₅₀ values of 0.155 μL/mL and 0.166 μL/mL respectively.

Conclusions

Essential oils from fruits of Monodora myristica, Xylopia aethiopica and Xylopia parviflora have shown acceptable antineoplastic potency, and might be investigated further in this regard.

Comparative Chemical Study and Cytotoxic Activity of Uvariodendron angustifolium Essential Oils from Benin

This study aimed to compare the chemical composition of volatile extracts obtained by hydrodistillation of leaves, stems, bark and roots of Uvariodendron angustifolium (Engl. & Diels) R. E. Fries. The essential oils, obtained with yields between 0.12 and 0.66%, were analyzed by GC/FID and GC/MS. A great variability in the chemical composition was observed depending on the plant part treated. The essential oils obtained from leaves and stems contained mainly neral (29.7–30.5%) and geranial (42.9–47.3%), while methyl eugenol was the major component of the volatile extracts from bark (68.3%) and roots (85.3%). Interesting cytotoxic properties of these essential oils on human breast cancer cells MCF-7 were demonstrated.

Comparative chemical study and cytotoxic activity of Uvariodendron angustifolium essential oils from Benin

This study aimed to compare the chemical composition of volatile extracts obtained by hydrodistillation of leaves, stems, bark and roots of Uvariodendron angustifolium (Engl. & Diels) R. E. Fries. The essential oils, obtained with yields between 0.12 and 0.66%, were analyzed by GC/FID and GC/MS. A great variability in the chemical composition was observed depending on the plant part treated. The essential oils obtained from leaves and stems contained mainly neral (29.7-30.5%) and geranial (42.9-47.3%), while methyl eugenol was the major component of the volatile extracts from bark (68.3%) and roots (85.3%). Interesting cytotoxic properties of these essential oils on human breast cancer cells MCF-7 were demonstrated.

Repellent, irritant and toxic effects of 20 plant extracts on adults of the malaria vector Anopheles gambiae mosquito

Pyrethroid insecticides induce an excito-repellent effect that reduces contact between humans and mosquitoes. Insecticide use is expected to lower the risk of pathogen transmission, particularly when impregnated on long-lasting treated bednets. When applied at low doses, pyrethroids have a toxic effect, however the development of pyrethroid resistance in several mosquito species may jeopardize these beneficial effects. The need to find additional compounds, either to kill disease-carrying mosquitoes or to prevent mosquito contact with humans, therefore arises. In laboratory conditions, the effects (i.e., repellent, irritant and toxic) of 20 plant extracts, mainly essential oils, were assessed on adults of Anopheles gambiae, a primary vector of malaria. Their effects were compared to those of DEET and permethrin, used as positive controls. Most plant extracts had irritant, repellent and/or toxic effects on An. gambiae adults. The most promising extracts, i.e. those combining the three types of effects, were from Cymbopogon winterianus, Cinnamomum zeylanicum and Thymus vulgaris. The irritant, repellent and toxic effects occurred apparently independently of each other, and the behavioural response of adult An. gambiae was significantly influenced by the concentration of the plant extracts. Mechanisms underlying repellency might, therefore, differ from those underlying irritancy and toxicity. The utility of the efficient plant extracts for vector control as an alternative to pyrethroids may thus be envisaged.

The Chemical Composition and Antibacterial Activities of the Essential Oils from Three Aframomum Species from Cameroon, and Their Potential as Sources of (E)-(R)-Nerolidol

Essential oils obtained by hydrodistillation of seeds, pericarps, leaves and rhizomes of Aframomum dalzielii, A letestuianum and A. pruinosum grown in Cameroon were analyzed by GC-FID and GC-MS. The seed oils of the three species were characterized by a high content of ( E)-( R)-nerolidol (>88.0 %), which was fully characterized by NMR spectroscopy and chiral GC analysis. The main constituents of the pericarp and rhizome oils were monoterpene hydrocarbons, mainly β-pinene (0.8%–22.9%) and sabinene (29.0%–42.3%), along with 1,8-cineole (4.5%–23.7%); leaf oils were characterized by sesquiterpenes, namely ( E)-β-caryophyllene (18.4%–82.4%) and caryophyllene oxide (4.5%–23.7%). The antibacterial activities of these essential oils and of nine pure compounds (sabinene, β-pinene, 1,8-cineole, linalool, racemic ( E)-nerolidol, ( E)-( R)-nerolidol, ( E)-β-caryophyllene, α-humulene and caryophyllene oxide) were assessed against Micrococcus luteus and Escherichia coli. The strongest activities were observed against E. coli. The seed essential oils and their major component, ( E)-( R)-nerolidol, exhibited the lowest MIC values (0.19-0.39 μL/mL), justifying their traditional use and their potential application as natural food preservatives.

Stability of benzylic-type isothiocyanates in hydrodistillation-mimicking conditions

Pentadiplandra brazzeana Baillon (Pentadiplandraceae) is known to contain benzyl-, 3-methoxybenzyl-, 4-methoxybenzyl-, 3,4-dimethoxybenzyl-, and indole-type glucosinolates, and the essential oil obtained from its roots is mainly constituted of benzyl isothiocyanate and benzyl cyanide. In a previous study by the authors, it was surmised that partial hydrolytic degradation of 4-methoxybenzyl isothiocyanate, one major expected compound, occurred during the hydrodistillation process of essential oil preparation. To probe this hypothesis, a selection of diversely substituted benzylic-type isothiocyanates was submitted to standard hydrodistillation-mimicking conditions. After extraction with dichloromethane, the reaction mixtures were analyzed using GC-MS. The aqueous phases resulting from liquid-liquid extraction were analyzed by HPLC and GC-MS. 2-Methoxybenzyl, 4-methoxybenzyl, 3,4-dimethoxybenzyl, and 3,4,5-trimethoxybenzyl isothiocyanates underwent conversion into 2-methoxybenzyl, 4-methoxybenzyl, 3,4-dimethoxybenzyl, and 3,4,5-trimethoxybenzyl alcohols, respectively, whereas benzyl, 3-methoxybenzyl, and 4-chlorobenzyl isothiocyanates were converted into the corresponding benzylamines.

Profile and quantification of glucosinolates in Pentadiplandra brazzeana Baillon

Glucosinolates (GLs) present in root, seed, and leaf extracts of Pentadiplandra brazzeana Baillon were characterized and quantified according to the ISO 9167-1 method based on the HPLC analysis of desulfo-GLs. The analyses were complemented by GC-MS analyses of the isothiocyanates (ITCs) generated from GL degradation by myrosinase. Glucotropaeolin (1a), glucolimnanthin (2a), and glucoaubrietin (3a) were shown to be present in the root extract, whereas the seed mainly contained 3a. 3,4-Dimethoxybenzyl GL (4a), glucobrassicin (5a) and traces of 1a were detected in the leaf extract. The products were fully characterized as their desulfo-counterparts by spectroscopic techniques.

Evaluation of Clausena anisata essential oil from Cameroon for controlling food spoilage fungi and its potential use as an antiradical agent

Investigations were conducted to determine the chemical composition, antifungal and antiradical activities of the essential oil extracted from the fresh leaves of Clausena anisata (Willd.) Hook. F. ex Benth (from Cameroon) against Aspergillus flavus, A. niger, A. parasiticus and Fusarium moniliforme. The essential oil obtained by hydrodistillation was analysed by GC and GC/MS. The disc diffusion method was used to evaluate the fungal growth inhibition at various concentrations of the oil while the antiradical activity of the essential oil was studied by the DPPH (diphenyl picryl hydrazyl) method. The main components obtained were E-ocimenone (15.1%), Z-ocimenone (11.5%), gamma-terpinene (11.4%) and germacrene D (10.9%). After 10 days of incubation on essential oil supplemented medium, the growth of A. flavus, A. niger, A. parasiticus and F. moniliforme were totally inhibited by 4, 5, 5 and 5 mg/mL of C. anisata essential oil, respectively. The antiradical activity of C. anisata essential oil (SC50 = 5.1 g/L) was less than that of butylated hydroxyl toluene (BHT), which was used as the reference compound (SC50 = 0.007 g/L). Results obtained in the present study indicate the possibility of exploiting C. anisata essential oil to fight strains of A. flavus, A. niger, A. parasiticus and F. moniliforme responsible for biodeterioration of stored food products.

Evaluation of Clausena anisata Essential Oil from Cameroon for Controlling Food Spoilage Fungi and its Potential Use as an Antiradical Agent

Investigations were conducted to determine the chemical composition, antifungal and antiradical activities of the essential oil extracted from the fresh leaves of Clausena anisata (Willd.) Hook. F. ex Benth (from Cameroon) against Aspergillus flavus, A. niger, A. parasiticus and Fusarium moniliforme. The essential oil obtained by hydrodistillation was analysed by GC and GC/MS. The disc diffusion method was used to evaluate the fungal growth inhibition at various concentrations of the oil while the antiradical activity of the essential oil was studied by the DPPH (diphenyl picryl hydrazyl) method. The main components obtained were E-ocimenone (15.1%), Z-ocimenone (11.5%), γ-terpinene (11.4%) and germacrene D (10.9%). After 10 days of incubation on essential oil supplemented medium, the growth of A. flavus, A. niger, A. parasiticus and F. moniliforme were totally inhibited by 4, 5, 5 and 5 mg/mL of C. anisata essential oil, respectively. The antiradical activity of C. anisata essential oil (SC50 = 5.1 g/L) was less than that of butylated hydroxyl toluene (BHT), which was used as the reference compound (SC50 = 0.007 g/L). Results obtained in the present study indicate the possibility of exploiting C. anisata essential oil to fight strains of A. flavus, A. niger, A. parasiticus and F. moniliforme responsible for biodeterioration of stored food products.

Chemical composition and insecticidal activity of essential oils of two aromatic plants from Ivory Coast against Bemisia tabaci G. (Hemiptera: Aleyrodidae)

Essential oils of aromatic plants with insecticidal properties are nowadays considered as alternative insecticides to protect cultures from attack by insect pest. The aims of the present work were to evaluate the toxicity of the essential oils vapors of two aromatic plants (Lippia multiflora Mold. and Aframomum latifolium K. Schum) against Bemisia tabaci and to characterize their chemical composition. The highest fumigant toxicity against B. tabaci adults was observed with the L. multiflora oil: by exposure to 0.4 microL/L air, the lethal time inducing 90% mortality (LT90) was below 2 hours for this essential oil whereas it reached 15 h in the case of the A. latifolium oil. Both oils were analyzed by GC-FID and GC-MS on two capillary columns. The oil of L. multiflora contained a majority of oxygenated terpenoids mainly represented by the two acyclic components linalool (46.6%) and (E)-nerolidol (16.5%); the oil of A. latifolium was dominated by hydrocarbonated terpenoids among them beta-pinene (51.6%) and beta-caryophyllene (12.3%) were the two major components.

Chemical Composition and Insecticidal Activity of Essential oils of two Aromatic plants from Ivory Coast against Bemisia tabaci G. (Hemiptera: Aleyrodidae)

Essential oils of aromatic plants with insecticidal properties are nowadays considered as alternative insecticides to protect cultures from attack by insect pest. The aims of the present work were to evaluate the toxicity of the essential oils vapors of two aromatic plants ( Lippia multiflora Mold. and Aframomum latifolium K. Schum) against Bemisia tabaci and to characterize their chemical composition. The highest fumigant toxicity against B. tabaci adults was observed with the L. multiflora oil: by exposure to 0.4 μL/L air, the lethal time inducing 90% mortality (LT90) was below 2 hours for this essential oil whereas it reached 15 h in the case of the A. latifolium oil. Both oils were analyzed by GC-FID and GC-MS on two capillary columns. The oil of L. multiflora contained a majority of oxygenated terpenoids mainly represented by the two acyclic components linalool (46.6%) and ( E)-nerolidol (16.5%); the oil of A. latifolium was dominated by hydrocarbonated terpenoids among them β-pinene (51.6%) and β-caryophyllene (12.3%) were the two major components.

Essential oil of Plectranthus tenuicaulis leaves from Gabon, source of (R),(E)-6,7-epoxyocimene. An unusual chemical composition within the genus Plectranthus

Water distilled essential oils from leaves of Plectranthus tenuicaulis (Hook. f.) J. K. Morton collected in Gabon were analyzed using GC-FID and GC-MS. The main constituent, unusual within the genus Plectranthus, was isolated and formally identified as being the (+)-(R)-enantiomer of (E)-6,7-epoxyocimene [(E)-myroxide]. This enantiomer, which represents about 75% of the essential oil, has been previously identified as a pheromone emitted by the male fruit-spotting bug Amblypelta nitida; this insect is responsible of destruction of most fruit crops in tropical and subtropical areas. The potential application of P. tenuicaulis essential oil in crop protection programs is discussed and the atypical chemical profile of the gabonese essential oil is compared with those previously reported in the genus Plectranthus (or Coleus).

Essential Oil of Plectranthus tenuicaulis Leaves from Gabon, Source of (R),(E)-6,7-Epoxyocimene. An Unusual Chemical Composition within the Genus Plectranthus

Water distilled essential oils from leaves of Plectranthus tenuicaulis (Hook. f.) J. K. Morton collected in Gabon were analyzed using GC-FID and GC-MS. The main constituent, unusual within the genus Plectranthus, was isolated and formally identified as being the (+)-( R)-enantiomer of ( E)-6,7-epoxyocimene [( E)-myroxide]. This enantiomer, which represents about 75% of the essential oil, has been previously identified as a pheromone emitted by the male fruit-spotting bug Amblypelta nitida; this insect is responsible of destruction of most fruit crops in tropical and subtropical areas. The potential application of P. tenuicaulis essential oil in crop protection programs is discussed and the atypical chemical profile of the gabonese essential oil is compared with those previously reported in the genus Plectranthus (or Coleus).

Antiplasmodial volatile extracts from Cleistopholis patens Engler & Diels and Uvariastrum pierreanum Engl. (Engl. & Diels) (Annonaceae) growing in Cameroon

In a search for alternative treatment for malaria, plant-derived essential oils extracted from the stem barks and leaves of Cleistopholis patens and Uvariastrum pierreanum (Annonaceae) were evaluated in vitro for antiplasmodial activity against the W2 strain of Plasmodium falciparum. The oils were obtained from 500 g each of stem barks and leaves, respectively, by hydrodistillation, using a Clevenger-type apparatus with the following yields: 0.23% and 0.19% for C. patens and 0.1% and 0.3% for U. pierreanum (w/w relative to dried material weight). Analysis of 10% (v/v) oil in hexane by gas chromatography and mass spectrometry identified only terpenoids in the oils, with over 81% sesquiterpene hydrocarbons in C. patens extracts and U. pierreanum stem bark oil, while the leaf oil from the latter species was found to contain a majority of monoterpenes. For C. patens, the major components were α-copaene, δ-cadinene, and germacrene D for the stem bark oil and β-caryophyllene, germacrene D, and germacrene B for the leaf oil. The stem bark oil of U. pierreanum was found to contain mainly β-bisabolene and α-bisabolol, while α- and β-pinenes were more abundant in the leaf extract. Concentrations of oils obtained by diluting 1-mg/mL stock solutions were tested against P. falciparum in culture. The oils were active, with IC(50) values of 9.19 and 15.19 μg/mL for the stem bark and leaf oils, respectively, of C. patens and 6.08 and 13.96 μg/mL, respectively, for those from U. pierreanum. These results indicate that essential oils may offer a promising alternative for the development of new antimalarials.

Chemical Investigations of Essential Oils from Endemic Cupressaceae Trees from New Caledonia

The volatile components obtained by hydrodistillation of leaves of C. neocaledonica Dummer, C. sulcata (Parlatore) Schlechter and N. pancheri (Carrière) de Laubenfels from New Caledonia were investigated for the first time by a combination of GC and GC–MS analysis, and compared with the heartwood oil compositions of the three species. The essential oils from C. sulcata and C. neocaledonica leaves contain a majority of monoterpenes while the leaf oil of N. pancheri is characterized by a high level of sesquiterpenoids. On the basis of the sesquiterpenoid composition of the wood- and leaf oils, N. pancheri is closely related to both New Caledonian Callitris spp. However, C. sulcata and C. neocaledonica oils remain distinct from N. pancheri and the Australian Callitris oils by the presence of compounds biosynthetically related to the bisabolyl cation, mainly barbatenes and thujopsene.

Chemical composition and biological activities of Santiria trimera (Burseraceae) essential oils from Gabon

Water-distilled essential oils from leaves and bark of Santiria trimera (Oliv.) Aubrév. (Burseraceae) collected in Gabon were analyzed using capillary GC-FID and GC-MS. The leaf essential oil, which is described for the first time, was dominated by sesquiterpenes (76.5%), among which alpha-humulene (34.6%) and beta-caryophyllene (14.9%) were the major components. The bark essential oil was almost exclusively monoterpenic, with alpha-pinene (51.5%) and alpha-terpineol (16.8%) as main constituents. The antimicrobial activities of both essential oils were tested against eight Gram-positive and three Gram-negative bacteria by using agar disc diffusion and broth microdilution methods; anticandidal effect was also tested on different strains of Candida albica. The Gram-negative bacteria were the less sensitive to the leaf essential oil, which was effective against Bacillus cereus and Enterococcus faecalis. The bark essential oil was more active and, in particular, exhibited significant antimicrobial activity against Proteus mirabilis, which was resistant to the leaf oil. A weak anticandidal effect of both essential oils was observed.

Chemical investigations of essential oils from endemic Cupressaceae trees from New Caledonia

The volatile components obtained by hydrodistillation of leaves of C. neocaledonica Dummer, C. sulcata (Parlatore) Schlechter and N. pancheri (Carrière) de Laubenfels from New Caledonia were investigated for the first time by a combination of GC and GC-MS analysis, and compared with the heartwood oil compositions of the three species. The essential oils from C. sulcata and C. neocaledonica leaves contain a majority of monoterpenes while the leaf oil of N. pancheri is characterized by a high level of sesquiterpenoids. On the basis of the sesquiterpenoid composition of the wood- and leaf oils, N. pancheri is closely related to both New Caledonian Callitris spp. However, C. sulcata and C. neocaledonica oils remain distinct from N. pancheri and the Australian Callitris oils by the presence of compounds biosynthetically related to the bisabolyl cation, mainly barbatenes and thujopsene.

Chemical Composition and Biological Activities of Santiria trimera (Burseraceae) Essential Oils from Gabon

Water-distilled essential oils from leaves and bark of Santiria trimera (Oliv.) Aubrév. (Burseraceae) collected in Gabon were analyzed using capillary GC-FID and GC-MS. The leaf essential oil, which is described for the first time, was dominated by sesquiterpenes (76.5%), among which α-humulene (34.6%) and β-caryophyllene (14.9%) were the major components. The bark essential oil was almost exclusively monoterpenic, with α-pinene (51.5%) and α-terpineol (16.8%) as main constituents. The antimicrobial activities of both essential oils were tested against eight Gram-positive and three Gram-negative bacteria by using agar disc diffusion and broth microdilution methods; anticandidal effect was also tested on different strains of Candida albica. The Gram-negative bacteria were the less sensitive to the leaf essential oil, which was effective against Bacillus cereus and Enterococcus faecalis. The bark essential oil was more active and, in particular, exhibited significant antimicrobial activity against Proteus mirabilis, which was resistant to the leaf oil. A weak anticandidal effect of both essential oils was observed.

Chemical composition and antimicrobial activity of the essential oils of leaves, roots and bark of Glossocalyx staudtii

The chemical composition of the essential oils obtained by hydrodistillation from air dried leaves, bark and roots of Glossocalyx staudtii Engl. grown in Gabon was analyzed by GC and GC-MS. The essential oil content was 0.84% (w/w), 0.28% (w/w), and 0.74% (w/w), respectively. The leaf oil was characterized by a high content of monoterpene hydrocarbons (64.8%), with beta-pinene (30.6%) and alpha-pinene (22.6%) as the major constituents. The oil obtained from the bark contained 30.5% of oxygenated monoterpenes with cryptone as the main constituent (11.5%) and 28.9% of aliphatic compounds, with 9.3% of 2-tridecanone; in the roots oil, the main component was 2-tridecanone (55.2%). The antimicrobial activity of the oils was studied by means of the agar disc diffusion and broth microdilution methods. The Gram positive bacteria were the most sensitive to the essential oils. A significant anticandidal effect of the bark essential oil was observed.

Chemical Composition and Antimicrobial Activity of the Essential Oils of Leaves, Roots and Bark of Glossocalyx staudtii

The chemical composition of the essential oils obtained by hydrodistillation from air dried leaves, bark and roots of Glossocalyx staudtii Engl. grown in Gabon was analyzed by GC and GC-MS. The essential oil content was 0.84% (w/w), 0.28% (w/w), and 0.74% (w/w), respectively. The leaf oil was characterized by a high content of monoterpene hydrocarbons (64.8%), with β-pinene (30.6%) and α-pinene (22.6%) as the major constituents. The oil obtained from the bark contained 30.5% of oxygenated monoterpenes with cryptone as the main constituent (11.5%) and 28.9% of aliphatic compounds, with 9.3% of 2-tridecanone; in the roots oil, the main component was 2-tridecanone (55.2%). The antimicrobial activity of the oils was studied by means of the agar disc diffusion and broth microdilution methods. The Gram positive bacteria were the most sensitive to the essential oils. A significant anticandidal effect of the bark essential oil was observed.

The Bark Essential Oil Composition and Chemotaxonomical Appraisal of Cedrelopsis Grevei H. Baillon from Madagascar

Cedrelopsis grevei is an aromatic and endemic tree of Madagascar. Its essential oil, resulting from its bark, and known under the name katrafay oil, is used in Madagascar in traditional medicine and in aromatherapy in the areas of the North. The chemical composition of this oil shows a great variability. This work proposed to study some determinants of this variability. Sampling was carried out tree by tree, in six representative sites of the distribution area of the species, followed by distillation and analysis by GC-MS. Twenty one samples were thus analyzed and 71 molecules were identified in at least one sample. A principal components analysis was performed considering the thirteen principal compounds identified in these essential oils. Four chemical patterns were distinguished. The first is characterized by eudesmane skeletons, mainly represented by selinenes (3.4-17.2%) and eudesmols (9.9-37.8% and 0-11.1% for the α- and γ- isomers, respectively); the second is rich in α-pinene (2.1-30.0%) and copaborneol (4.7-20.0%); the third is dominated by α-copaene (5.9-11.8%) and ishwarane (13.7-22.1%), and the last by cadinane skeletons (cadinenes 0.5-35.2%, T-muurolol 0-11.8% and α-cadinol 0-6.7%). Variable amounts of α-bisabolol were found in samples belonging to these four groups. Our study indicates a linkage between the zone of gathering and the essential oil chemical composition. There was not much variability between trees in the same zone, but there were big differences from one zone to another. These results make it possible to propose methods for sustainable collection and durable management of the species.