Terpenoids as Important Bioactive Constituents of Essential Oils

Plant and plant-derived natural products have a long and significant history in traditional medicine all over the world. Many studies in the recent past years focused on the benefic properties of essential oils (EOs) and their major components, terpenes and terpenoids (that are mostly monoterpenes and sesquiterpenes), and their biological properties. This chapter focuses on terpenoids as important bioactive constituents of EOs. It describes their uses, importance, extraction processes, and classification. The chapter provides an in-depth overview of the latest findings/research about terpenoids in EOs. It contains a well-prepared background, introduction, classification, chemical tests, bioactivities, as well as the characterization of terpenoids. It also discusses the bioactivities of EOs and that of terpenoids, with regard to their synergetic and/or their antagonistic effects

Dewerin and gilbertionol two new secondary metabolites from the stem bark of Gilbertiodendron dewevrei (De Wild) J. Leonard.

Stephanie DM, Stephane FFY, Jules BKJ, et al. Dewerin and gilbertionol two new secondary metabolites from the stem bark of Gilbertiodendron dewevrei (De Wild) J. Leonard. Natural product research. 2020.The phytochemical investigation of the methanol extract of the stem bark of Gilbertiodendron dewevrei led to the isolation of two new secondary metabolites, 5,7-dihydroxy-4'-methoxyisoflavan-2,4-dione (1) and 23-hydroxy-2-tricosanone (2) along with 19 known compounds (3-21). The structure of these compounds were established by interpretation of their spectral data, mainly HR-TOFESIMS, 1D NMR (1H, 13C and DEPT) and 2D NMR (1H-1H COSY, HSQC, HMBC, and NOESY), and by comparison with those reported in the literature. The methanol extract and some isolates were screened for their antiradical, antibacterial, and inhibitory properties against acetylcholinesterase

In vitro antiplasmodial activity and toxicological profile of extracts, fractions and chemical constituents of leaves and stem bark from Dacryodes edulis (Burseraceae)

Dongmo KJJ, Tali MBT, Fongang YSF, et al. In vitro antiplasmodial activity and toxicological profile of extracts, fractions and chemical constituents of leaves and stem bark from Dacryodes edulis (Burseraceae). BMC Complementary Medicine and Therapies. 2023;23(1): 211.BACKGROUND: Dacryodes edulis is a plant that belongs to the Burseraceae family. It is widely used traditionally alone or in association with other plants in Cameroonian folk medicine to cure wounds, fever, headaches, and malaria. The aim of this work was to investigate the leaves and stem bark of D. edulis with an emphasis on the antiplasmodial and cytotoxic effects of extracts, fractions, and isolated compounds.; METHODS: Extracts, fractions, and some isolated compounds were subjected to antiplasmodial activity screening in vitro against chloroquine-sensitive 3D7 and multidrug resistant Dd2 strains of Plasmodium falciparum using a SyBr Green fluorescence-based assay. The cytotoxicity of active extracts, fractions, and compounds was tested against mammalian Raw cell lines using an in vitro resazurin-based viability assay. The structures of the compounds were determined based on their NMR and MS data. The in vivo toxicity using female BALB/c mice was performed on the most active extract according to the protocol of OECD (2002), guideline 423.; RESULTS: The hydroethanolic extract from the leaves of D. edulis displayed good antiplasmodial activity with IC50 values of 3.10 and 3.56mug/mL respectively on sensitive (3D7) and multiresistant (Dd2) strains of P. falciparum. Of the sixteen compounds isolated, 3,3',4-tri-O-methylellagic acid (4) exhibited the highest antiplasmodial activity against PfDd2 strains with an IC50 value of 0.63mug/mL. All extracts, fractions, and isolated compounds demonstrated nocytotoxicity against Raw cell lines with CC50>250mug/mL. In addition, the most active extract on both strains of P. falciparum was nontoxic in vivo, with a LD50 greater than 2000 and 5000mg/kg. A phytochemical investigation of the stem bark and leaves of D. edulis afforded sixteen compounds, including two xanthones (1-2), three ellagic acid derivatives (3-5), one phenolic compound (6), one depside (7), one triglyceride (8), one auranthiamide acetate (9), one gallic acid derivative (10), four triterpenoids (11-14), and two steroids (15-16). Compounds 1, 2, 5, 7, 8, and 9 were herein reported for the first time from the Burseraceae family.; CONCLUSION: This work highlights the good in vitro antiplasmodial potency of the hydroethanolic extract of the leaves of this plant and that of two isolated constituents (3,3',4-tri-O-methylellagic acid and ethylgallate) from the plant. These biological results support the use of D. edulis in traditional medicine against malaria. © 2023. The Author(s)

Constituents of Peperomia vulcanica Baker & C. H. Wright (Piperaceae) with antiparasitic activity

Chouna HSD, Bankeu JJK, Fongang YSF, et al. Constituents of Peperomia vulcanica Baker & C. H. Wright (Piperaceae) with antiparasitic activity. PHYTOCHEMISTRY LETTERS. 2021;41:14-20.The investigation of the CH2Cl2-MeOH (1:1) extract of Peperomia vulcanica which showed antileishmanial activity during preliminary screening led to the isolation of two previously unknown compounds named peperolignan (1) and peperotannin (2) along with 13 known compounds. Their structures were determined on the basis of their spectroscopic data. The isolated compounds were assessed in vitro for their antileishmanial and antiplasmodial activities against Leishmania donovani 1S (MHOM/SD/62/1S) promastigotes and the Plasmodium falciparum chloroquine-sensitive 3D7 strain (Pf3D7), respectively. They were also assessed for their cytotoxicity on Raw 264.7 macrophage cells. The mixture of 4-hydroxy-2[(3,4-methylenedioxyphenyl)nonanoyl)cyclo-hexan-1,3-dione and 4-hydroxy-2[(3,4-methylenedioxyphenyl) undecanoyl] cyclo-hexane-1,3-dione (10a and 10b) exhibited potent antiplasmodial activity (IC50 = 0.35 mu g/mL) with selectivity index higher than 10-fold (SI = 63.4) and moderate leishmanicidal activity (IC50 = 12.17 mu g/mL) with very low selectivity index (SI = 1.82). The obtained results could provide an extent of validation to the traditional uses of Peperomia vulcanica for the treatment of malaria in endemic areas

Constituents from Nauclea latifolia with Anti-Haemophilus influenzae Type b Inhibitory Activities.

Kezetas Bankeu JJ, Kenou Kagho DU, Fotsing Fongang YS, et al. Constituents from Nauclea latifolia with Anti-Haemophilus influenzae Type b Inhibitory Activities. Journal of Natural Products. 2019;82(9):2580-2585.Three previously undescribed indole alkaloids, named latifolianine A (1) and latifoliaindoles A and B (2 and 3), along with 10 known compounds (4-13), were isolated from the heartwood of Nauclea latifolia. Their structures were elucidated based on the analysis of their NMR and MS data. Latifolianine A (1) represents an unusual and unprecedented monoterpene indole alkaloid unit condensed with an ursane-type pentacyclic triterpenoid moiety. Plausible biogenetic routes toward latifolianine A (1) and latifoliaindoles A and B (2 and 3) were proposed. All the isolates were assessed in vitro for their inhibitory effects on Haemophilus influenzae. Naucleidinal (7) exhibited potent antibacterial activity (MIC value of 3.1 mug/mL) as compared to a reference drug, ciprofloxacin (MIC value of 1.6 mug/mL)

Constituents from ripe figs of Ficus vallis-choudae Delile (Moraceae) with antiplasmodial activity

Chouna HSD, Dize D, Kagho DUK, et al. Constituents from ripe figs of Ficus vallis-choudae Delile (Moraceae) with antiplasmodial activity. Parasitology Research. 2022.Ripe figs, barks, and wood of Ficus vallis-choudae are used in traditional medicine against several conditions including nausea and malaria. However, its use is still to be scientifically documented and validated. Hence, the aim of the present work was to evaluate the antiplasmodial activity of the dichloromethane-methanol (DCM-MeOH (1:1)) crude extract, their hexane, dichloromethane, ethyl acetate, and methanoli fractions, as well as the isolated chemical constituents. The chemical study of the DCM-MeOH (1:1) crude extract of F. vallis-choudae figs led to the isolation of fifteen (15) known compounds identified based on their spectroscopic data [one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR), mass spectrometry] and by comparison of these data with those reported in the literature. Some of the isolated compounds were assessed in vitro for their antiplasmodial activity against Plasmodium falciparum chloroquine-sensitive 3D7 (Pf3D7) and multidrug-resistant Dd2 strains. The dichloromethane fraction exhibited very good antiplasmodial activity against both strains with IC50 values of 13.86mug/mL and 8.18mug/mL, respectively. Among the tested compounds, wighteone (2) was the most active against P. falciparum 3D7 (IC50=24.6±1.5muM) and Dd2 (IC50=11.9±2.4muM) strains. The obtained results could justify the traditional uses of F. vallis-choudae against malaria. Wighteone appears to be the most active ingredient. However, further consideration of this compound as starting point for antimalarial drug discovery will depend upon its selectivity of action towards Plasmodium parasites. HIGHLIGHTS: 15 (fifteen) compounds were isolated from the dichloromethane-methanol extract of Ficus vallis-choudae. Their structures were determined on the basis of their spectroscopic data. The dichloromethane fraction showed promising activities on the Pf3D7 and PfDd2 strains with IC50 values of 13.86 and 8.18g/mL, respectively. Wighteone was the most active compound against PfDd2 (IC50=11.9±2.4muM). © 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature