Endiandric Acid Derivatives and Other Constituents of Plants from the Genera Beilschmiedia and Endiandra (Lauraceae)

Lenta Ndjakou B, Chouna JR, Nkeng-Efouet PA, Sewald N. Endiandric Acid Derivatives and Other Constituents of Plants from the Genera Beilschmiedia and Endiandra (Lauraceae). BIOMOLECULES. 2015;5(2):910-942.Plants of the Lauraceae family are widely used in traditional medicine and are sources of various classes of secondary metabolites. Two genera of this family, Beilschmiedia and Endiandra, have been the subject of numerous investigations over the past decades because of their application in traditional medicine. They are the only source of bioactive endiandric acid derivatives. Noteworthy is that their biosynthesis contains two consecutive non-enzymatic electrocyclic reactions. Several interesting biological activities for this specific class of secondary metabolites and other constituents of the two genera have been reported, including antimicrobial, enzymes inhibitory and cytotoxic properties. This review compiles information on the structures of the compounds described between January 1960 and March 2015, their biological activities and information on endiandric acid biosynthesis, with 104 references being cited

Extraction of Bioactive Compounds from Medicinal Plants and Herbs

Human beings have relied on herbs and medicinal plants as sources of food and remedy from time immemorial. Bioactive compounds from plants are currently the subject of much research interest, but their extraction as part of phytochemical and/or biological investigations present specific challenges. Herbalists or scientists have developed many protocols of extraction of bioactive ingredients to ensure the effectiveness and the efficacy of crude drugs that were used to get relief from sickness. With the advent of new leads from plants such as morphine, quinine, taxol, artemisinin, and alkaloids from Voacanga species, a lot of attention is paid to the mode of extraction of active phytochemicals to limit the cost linked to the synthesis and isolation. Thus, the extraction of active compounds from plants needs appropriate extraction methods and techniques that provide bioactive ingredients-rich extracts and fractions. The extraction procedures, therefore, play a critical role in the yield, the nature of phytochemical content, etc. This chapter aims to present, describe, and compare extraction procedures of bioactive compounds from herbs and medicinal plants

Plant-Derived Compounds against Microbial Infections and Cancers

Plants synthesize and preserve a variety of metabolites known as natural products. Many of them are easily extractable and can be used as starting material or chemical scaffolds for various purposes, especially in drug discovery. Numbers of reports have listed valuable candidates with privilege scaffolds currently in active development as drugs. New compounds with anticancer and antiinfective activities have been discovered recently, some presented these backbones. The present book chapter aims to highlight these findings from plants which can be considered valuable for the development of new drugs against malignant cells and infective diseases. Interest in anti-infective agents is increasing due to the resistance of microorganisms to existing drugs and newly emerging infectious diseases. This resistance is also, nowadays, associated to some forms of cancers. In addition, the value of plants as essential part in the health care pipeline in low- and middle-income countries is under consideration even though these countries are almost all surrounded by a rich and untapped biodiversity. People are always relying on “modern drugs and treatment” which is unfortunately not affordable to all. Therefore, the present compilation of data on plant-derived compounds can inspire the formulation of ameliorated traditional medicines (ATM) against the targeted diseases and the conservation of species

4-(1,1-dimethylprop-2-enyl)-1,3,5-trihydroxy-2-(3-methylbut-2-enyl)-9H-x anthen-9-one

Lenta BN, Devkota KP, Neumann B, Tsamo E, Sewald N. 4-(1,1-dimethylprop-2-enyl)-1,3,5-trihydroxy-2-(3-methylbut-2-enyl)-9H-x anthen-9-one. Acta Cryst. E. 2007;63(4):o1629-o1631.The title compound, also known as allanxanthone A, C23H24O5, was isolated from the medicinal plant Allanblackia monticola (Clusiaceae). The 9H-xanthen-9-one system is essentially planar. The crystal structure is stabilized by intra- and intermolecular hydrogen bonds

Antimicrobial triterpenes from the stem bark of crossopteryx febrifuga

Chouna JR, Tamokou J-de-D, Nkeng-Efouet-Alango P, Lenta BN, Sewald N. Antimicrobial triterpenes from the stem bark of crossopteryx febrifuga. Zeitschrift für Naturforschung C. 2015;70(7-8):169-173.Phytochemical investigation of the stem bark extract of Crossopteryx febrifuga resulted in the isolation of epimeric mixtures of 3 beta-urs-12,20(30)-diene-27,28-dioic acid and 18-epi-3 beta-urs-12,20(30)-diene-27,28-dioic acid (1), as well as: 3 beta-D-glucopyranosylurs-12,20(30)-diene-27,28-dioic acid and 18-epi-3 beta-D-glucopyranosylurs-12,20(30)-diene- 27,28-dioic acid (2), together with some known compounds such as the monoglyceride of palmitic acid, as well as beta-sitosterol and its glucoside. The structures of the isolated compounds were determined by application of spectroscopic methods. The MeOH extract and compounds 1 and 2 were examined for antimicrobial activity in in vitro assays against bacteria (Enterobacter aerogenes ATCC13048, Escherichia coli ATCC8739, Klebsiella pneumoniae ATCC11296, Staphylococcus aureus) and fungi (Candida parapsilosis, Candida albicans ATCC 9002 and Cryptococcus neoformans IP 90526). The tested samples showed selective activities. The antibacterial and antifungal activities of compound 2 (MIC = 8-64 mu g/mL) were in some cases equal to or even higher than those of the respective reference drugs chloramphenicol (MIC = 16-64 mu g/mL) and nystatin (MIC = 128-256 mu g/mL)

Obscurine: a New Cyclostachine Acid Derivative from Beilschmiedia obscura

Lenta BN, Chouna JR, Nkeng-Efouet PA, Kimbu SF, Tsamo E, Sewald N. Obscurine: a New Cyclostachine Acid Derivative from Beilschmiedia obscura. Natural Product Communications. 2011;6(11):1591-1592.From the methylene chloride extract of the stem bark of Bedschmiedia obscura, a new cyclostachine derivative, obscurine (1), has been isolated, together with six known compounds. The structure of compound 1 was established by spectroscopic methods, including 1- and 2-dimensional NMR techniques

Ergostane-type steroids from the Cameroonian 'white tiama' Entandrophragma angolense.

Happi GM, Wouamba SCN, Ismail M, et al. Ergostane-type steroids from the Cameroonian 'white tiama' Entandrophragma angolense. Steroids. 2020;156: 108584.Two new ergostane-type steroids named tiamenones A and B (1-2) were isolated from the bark of Entandrophragma angolense (Meliaceae) along with ten known compounds identified as 20S-hydroxy-4,6,24(28)-ergostatrien-3-one (3), 3beta,7alpha,20beta-trihydroxyergosta-5,24(28)-diene (4), 3beta,5alpha-dihydroxyergosta-7,22-diene (5), stigmasterol, beta-sitosterol, beta-amyrin, oleanolic acid, asperphenamate, sucrose and daucosterol. The structures of the isolated compounds have been established using NMR spectroscopic and mass spectrometric analyses. The assignment of relative and absolute configurations of compound 1 was achieved by a NOESY experiment and comparison of its NMR data with those of known compound reported in literature. Compounds 1-3, beta-amyrin and asperphenamate were evaluated for their antibacterial potencies against five bacterial model strains viz. Escherichia coli DSMZ 1058, Pseudomonas agarici DSMZ 11810, Bacillus subtilis DSMZ 704, Micrococcus luteus DMSZ 1605 and Staphylococcus warneri DSMZ 20036 and their cytotoxicity on two cell lines KB3-1 and HT-29. No potencies were exhibited by the tested compounds even at the highest concentration of 0.5 mg/mL. Compounds 1-3 were found to be potential HIV-1 inhibitors based on their molecular docking analyses. Copyright © 2020. Published by Elsevier Inc

Endiandric acid derivatives from the stem bark of Beilschmiedia anacardioides

Chouna JR, Nkeng-Efouet PA, Lenta BN, Wansi JD, Kimbu SF, Sewald N. Endiandric acid derivatives from the stem bark of Beilschmiedia anacardioides. Phytochemistry Letters. 2010;3(1):13-16.Three new endiandric acid derivatives, beilschmiedic acids D, E and beilschmiedin were isolated from the stem bark of Beilschmiedia anacardioides together with the known compounds bisabolene and tricosanoic acid. Their structures were determined on the basis of spectroscopic analysis. (C) 2009 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved

Isoderrone

Bankeu Kezetas JJ, Ndjakou Lenta B, Ngouela S, et al. Isoderrone. Acta Crystallographica. Section E, Crystallographic Communications. 2007;63(2):o523-o525.The title compound, C20H16O5, also known as 5,7-dihyroxy-3-(2',2'-dimethyl-2H'-chromen-7'-yl) chroman-4-one, was isolated from the medicinal plant Ficus mucuso. The benzopyranone (chromen-4-one) ring system is essentially planar and the dihedral angle between the benzopyranone ring system and the other benzene ring is 37.7 (10)degrees. In the crystal structure, one-dimensional chains are formed via intermolecular O-H center dot center dot center dot O hydrogen bonds