Phytochemical investigation and biological activities of Lantana rhodesiensis

peer reviewedLantana rhodesiensis Moldenke is a plant widely used to treat diseases, such as rheumatism, diabetes, and malaria in traditional medicine. To better understand the traditional uses of this plant, a phytochemical study was undertaken, revealing a higher proportion of polyphenols, including flavonoids in L. rhodesiensis leaf extract and moderate proportion in stem and root extracts. The antioxidant activity of the extracts was also determined using three different assays: the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, the FRAP method (Ferric-reducing antioxidant power) and the β-carotene bleaching test. The anti-malarial activity of each extract was also evaluated using asexual erythrocyte stages of Plasmodium falciparum, chloroquine-sensitive strain 3D7. The results showed that the leaf extract exhibited higher antioxidant and anti-malarial activities in comparison with the stem and root extracts, probably due to the presence of higher quantities of polyphenols including flavonoids in the leaves. A positive linear correlation was established between the phenolic compound content (total polyphenols including flavonoids and tannins; and total flavonoids) and the antioxidant activity of all extracts. Furthermore, four flavones were isolated from leaf dichloromethane and ethyl acetate fractions: a new flavone named rhodescine (5,6,3’,5’-tetrahydroxy-7,4’-dimethoxyflavone) (1), 5-hydroxy-6,7,3’,4’,5’-pentamethoxyflavone (2), 5-hydroxy-6,7,3′,4′-tetramethoxyflavone (3), and 5,6,3’-trihydroxy-7,4’-dimethoxyflavone (4). Their structures were elucidated by 1H, 13C NMR, COSY, HSQC, HMBC, and MS-EI spectral methods. Aside from compound 2, all other molecules were described for the first time in this plant species.EOHUB project 600873EPP-1-2018-1ES-EPPKA2-K

Etude phytochimique et biologique de deux plantes médicinales de Côte d’Ivoire : Lantana camara et Lantana rhodesiensis (Verbenaceae)

Cette thèse a pour but de contribuer à l’étude phytochimique de Lantana camara Lin et Lantana rhodesiensis Moldenke, et de justifier leurs utilisations dans la médecine traditionnelle ivoirienne. La première partie a consisté à la détermination de la composition chimique et à l’évaluation des activités biologiques de l’huile essentielle des organes de ces plantes. Les échantillons d’huile essentielle ont été obtenus par hydrodistillation et analysés par CPG-SM, CPG-FID-IR et RMN 13C. Les résultats ont montré que la composition chimique de l’huile essentielle des organes est majoritairement dominée par l’(E)-β-caryophyllène et l’α-humulène. Les monoterpènes tels que le thymol, le sabinène et le 1,8-cinéole y sont parfois majoritaires. L'analyse statistique des échantillons d’huile essentielle a révélé une variabilité de la composition chimique des organes. En outre, l'impact de la variabilité due au stade phénologique sur la composition de l’huile essentielle des organes de L. camara a été démontré. Il ressort que la proportion de thymol est plus élevée pendant les mois de floraison et de fructification intense. La variation chimique de l’huile essentielle de L. camara serait également liée aux facteurs biogéographiques et génétiques. L’huile essentielle des feuilles et des fleurs présente des activités insecticide, antioxydante et anti-inflammatoire intéressantes. La deuxième partie a consisté à l’exploration phytochimique bio-guidée des organes de L. rhodesiensis. Le screening phytochimique a permis de mettre en lumière une plus grande richesse des feuilles en polyphénols et flavonoïdes. L’extrait des feuilles présente une activité antioxydante et antiplasmodiale plus élevée par rapport à l’extrait des tiges et des racines. Plusieurs fractions de l’extrait des feuilles ont révélé une activité antiplasmodiale intéressante (15 ˃ CI50 ˂ 3 µg/mL). À partir des feuilles, une nouvelle flavone (1) et trois autres flavones ont été isolés, il s’agit de : rhodescine ou 5,6,3’,5’-tétrahydroxy-7,4’-diméthoxyflavone (1); 5-hydroxy-6,7,3’,4’,5’-penta-méthoxyflavone (2); 5-hydroxy-6,7,3’,4’-tétramethoxy-flavone (3) et 5,6,3'-trihydroxy-7,4'-diméthoxyflavone (4). La structure de chacun de ces composés a été élucidée par les méthodes spectrales de RMN 1H, 13C, COSY, HSQC, HMBC et LC-MS. Les composés 1, 3 et 4 ont été identifiés pour la première fois à partir de cette espèce. Le pourcentage d’inhibition (%I) du radical DPPH de chaque composé (1mg/mL) a été déterminé. La rhodescine (1) (%I = 97,92 ± 0,20) présente un pourcentage d’inhibition proche de celui de l’acide ascorbique (%I = 98,50 ± 0,56) et de la quercétine (%I = 98,89 ± 0,74). Le pourcentage d’inhibition du composé 4 est moyen (%I = 61,77 ± 3,53) tandis que celui des composés 2 et 3 est faible. Les résultats de ces travaux de recherche permettent de justifier l’usage de ces deux plantes dans la médecine traditionnelle, notamment dans le traitement du rhumatisme et de la malaria. Ces travaux ouvrent des perspectives sur d’autres investigations scientifiques qui pourraient aboutir à l’identification de nouveaux métabolites secondaires à potentialité antioxydante et antipaludique

Composition chimique et activité insecticide de l’huile essentielle de Lantana camara

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Chemical Investigation on Leaf, Flower and Fruit Oils ofLantana camara from Côte d’Ivoire

International audienceThe compositions of essential oil obtained from leaves, flowers and fruits of Lantana camara L. growing in wild at Côte d’Ivoire, were investigated by GC and13C NMR. Thirty-seven compounds accounting for 88.3–94.5% of the oils have been identified. The leaf, flower and fruits of L. camara producedsesquiterpene-rich essential oils predominated by (E)-β-caryophyllene and α-humulene, in addition to the important content of sabinene, -phellandrene andthymol as monoterpenes. It was found the new chemical profiles of L. camar

Antioxidant and Lipoxygenase Inhibitory Activities of Essential Oils from Endemic Plants of Côte d’Ivoire: Zanthoxylum mezoneurispinosum Ake Assi and Zanthoxylum psammophilum Ake Assi

Zanthoxylum mezoneurispinosum Ake Assi and Zanthoxylum psammophilum Ake Assi are species endemic to Côte d’Ivoire. In this study, we determined, for the first time, the composition and biological activities of essential oils obtained from each of these plants. Essential oils were obtained by hydrodistillation from different organs of each plant with a Clevenger-type apparatus and analyzed by gas chromatography–mass spectrometry (GC-MS). Thirty-four components, accounting for more than 99.9% of the overall composition, were identified in the oils. The Z. psammophilum leaf and trunk bark oils exhibited two unusual methylketones, undecan-2-one and tridecan-2-one, whereas the root oil was rich in thymol and sesquiterpenoids. The Z. mezoneurispinosum leaf and trunk bark oils were rich in monoterpenoids, whereas sesquiterpenoids were predominant in the root oil. These samples produced, for the first time, some new chemical profiles of essential oils. The oils’ antioxidant activities were determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity and ferric reducing antioxidant power (FRAP) assays. The results showed that the essential oil isolated from roots of Z. mezoneurispinosum had the highest antioxidant activity, which is in accordance with the high thymol content of that oil. We also determined the lipoxygenase inhibitory activities of the essential oils. The results showed that all of the tested oils displayed high and close lipoxygenase inhibitory activities.EOHUB project, grant number 600873-EPP-1-2018-1ES-EPPKA2-KA

New essential oils with interesting biological activities from endemic plants of Côte d'Ivoire: Zanthoxylum mezoneurispinosum and Zanthoxylum psammophilum

New essential oils with interesting biological activities from endemic plants of Côte d’Ivoire: Zanthoxylum mezoneurispinosum (Ake Assi) and Zanthoxylum psammophilum (Ake Assi). Evelyne A. Tanoh1*, Fatimata Nea1, Tierry K. Kenne2, Manon Genva2, Matthew Saive2, Felix Z. Tonzibo1, Marie-Laure Fauconnier2. 1 Laboratory of Biological Organic Chemistry, UFR-SSMT, University Felix Houphouet-Boigny, BPV 34 Abidjan, Côte d’Ivoire 2 Laboratory of Natural Molecules Chemistry, University of Liège, Gembloux Agro- Bio Tech, 2, Passage of Deportés, B-5030 Gembloux, Belgium According to OMS nearly 80% of the population depend on traditional medicine given the strong growth in the use of natural products from plants1. Many Rutaceae plants are already used in traditional medicine for their biological properties such as anticancer and antioxidant activities. Zanthoxylum mezoneurispinosum (Ake Assi) and Zanthoxylum psammophylum (Ake Assi) are endemic Rutaceae to Côte d’Ivoire. In order to determine if those plants could be used in medicine, the aim of this work was to evaluate the chemical composition and the biological activities of essential oils extracted from both plants. Essential oils of our plants isolated from the leaves, trunk bark and roots. Their chemical compositions were determined by GC-MS. In vitro biological properties were determined using two activities: Antioxidant and anti-inflammatory. The analysis of the essential oils of leaves, trunk bark and roots of Z. psammophylum exhibit the predominance of two unusual methyl ketones, 2-undecanone and 2-tridecanone in leaves and trunk bark. These compounds have biological properties according to the literature2. The root is rich in thymol. Z. mezoneurispinosum oil is rich in alpha pinene for leaves and trunk bark, while the root is rich in gamma-elemene and cyclosativene. Cyclosativene is known for its biological activities3. The essential oils of both plants showed in increasing order antioxidant value in the leaves, trunk bark and roots. A measure of anti-inflammatory activity was found to in decreasing order in the root, followed by leaves and trunk bark. These plants could constitute a source of active molecules for traditional medicine in Côte d'Ivoire. However, although these plants are endemic in this country, they are not abundant and it is necessary to limit and protect the distribution of nurseries to produce plants and reintroduce these species into their natural habitat. References 1- O.M.S, 2002. : Besoins et potentiel. N° 4. 6 p. 2- Saini Mukesh and al, (2014). J. Agric. Food. Chem, 62: 4342 – 4348. 3- Kang Min-Seung, Lee Hoi-Seon, (2018). Applied Biological chemistry 61 (6): pp 653 – 659

Variability of essential oil composition and biological activities of Lantana rhodesiensis Moldenke from Côte d'Ivoire.

Lantana rhodesiensis Moldenke is an herb or small shrub under two meters tall which is often multi-stemmed 1. It is used in traditional medicine for several treatments like diabetes1, rheumatism2, and arterial hypertension3. The aim of the present study was to determine the variation in the chemical composition of essential oils of L. rhodesiensis from Côte d’Ivoire. It also aimed to evaluate the in vitro antioxidant and anti-inflammatory activities of essential oils. Essential oils were obtained by hydrodistillation from leaves, stems and fruits of L. rhodesiensis from two localities of Northern Côte d’Ivoire. Essential oil composition was determined by GC-MS. The study of the antioxidant activity of leave essential oils was carried out by the DPPH and FRAP method; the anti-inflammatory activity was evaluated by the inhibition of protein denaturation method. Results showed that the main constituents present in most essential oils extracted from leaves, fruits and stems were β-caryophyllene, α-copaene, δ-cadinene and α-humulene. However, thymol was the major component in three leave samples. The stem oils are also dominated by caryophyllene oxide or thymol. It may be concluded that the sesquiterpenes were the predominant molecules in all essential oil samples of L. rhodesiensis from Northern Côte d'Ivoire. The results of the biological activities carried out on the leave essential oil samples showed that these oils have antioxidant and anti-inflammatory activities. This study showed the interest of L. rhodesiensis for the treatment of rheumatism and diabetes in traditional medicine. L. rhodesiensis is a potential source for isolating new antioxidant and anti-inflammatory molecules. 1. Piero, N. M. et al. J Dev. Drugs 4, 2 (2015). 2. Ruffo CK, Birnie A, Tengnas B. Edible wild plants of Tanzania p418 (2002). 3. JeanBangou, M., Kiendrebeogo, M., Compaoré, M. & Coulibaly, A. Y. J. Biol. Sci. 11, 31–38 (2011)

Seasonal variation, yield composition and biological activities of essential oils from Lantana camara grown in Côte d’Ivoire

Lantana camara is a thorny shrub that goes from 2 to 5 m high. Its ripe fruits are blackish and its flowers are in various colors. It is used in traditional medicine to treat several diseases and has numerous properties that were chemically described such as antioxidant, antibacterial and cytotoxic activities. The aim of this work was to study the variations in L. camara essential oils composition during the vegetative cycle. Leaves, flowers, fruits and stems of L. camara were harvested in Bingerville (East Côte d'Ivoire) each month from June 2015 to June 2017. The essential oil was produced by hydrodistillation and then analyzed by GC-MS and RMN. The antioxidant, anti-inflammatory and insecticidal activities of leaf and flowers essential oils were also determined. Results showed that essential oils hydrodistillated from L. camara are dominated by sesquiterpenes such as β-caryophyllene and α-humulene. Some monoterpenes such as thymol, sabinene and α-pinene were also present. The oil yield was high during the flowering and fruiting period. According to the chemical composition of L. camara’s oil, there were no significant differences between both harvesting periods defined but there were significant differences from one organ to another. However, within one organ the chemical composition varies under the vegetative cycle. It was found that the proportion of thymol was higher during flowering and fruiting months. The essential oil of stems, flowers, and fruits were more concentrated in thymol than leaf’s oil. E-β-caryophyllene and α-humulene were found in all essential oils. However, their quantity and the thymol content were strictly inverted throughout the harvest period or vegetative cycle. In addition, the essential oil extracted from leaves and flowers of L. camara showed good antioxidant, anti-inflammatory and insecticidal activities