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

Evaluation of In Vitro Uterotonic Activities of Fruit Extracts of Ficus asperifolia in Rats

The aim of the present study was to determine the uterotonic activities of Ficus asperifolia and investigate its mechanism. The effects of aqueous and methanol extracts of the dried fruits of F. asperifolia (0.05–1.60 mg mL−1) were evaluated on estrogenized isolated rat uterus in the presence and absence of atropine (1.73–55.27 nM), pyrilamine maleate (1.25 × 10−3 to 40 × 10−3 M), indomethacin (0.06 × 10−5 to 2.00 × 10−5 M) or hexamethonium (0.66 × 10−4 to 21.43 × 10−4 M). Aqueous (EC50, 0.36 mg mL−1) and methanol (EC50, 0.22 mg mL−1) extracts as well as oxytocin (EC50, 0.02 nM), acetylcholine (EC50, 7.87 nM) and histamine (EC50, 0.76 nM) evoked concentration-dependent contractions of the uterus. Atropine, pyrilamine maleate and indomethacin concentration dependently blocked the response of the uterus to acetylcholine (IC50, 4.82 nM), histamine (IC50, 2.49 nM) and oxytocin (IC50, 0.07 nM), respectively, and to aqueous extract. Hexamethonium produced graded decreases in oxytocin-induced uterine contractions (IC50, 0.37 μM), but did not prevent the contractile effects of the aqueous extract (IC50, 9.88 μM). These results suggest that F. asperifolia-induced uterotonic effect is related to the release of prostaglandins and contraction of the myometrial cells through muscarinic, oxytocic and H1 histamine receptors. These data further give added value to the ethnic use of F. asperifolia for its abortificient and contraceptive properties

The Aqueous and Methanol Extracts of Ficus asperifolia (Moraceae) Improve Reproductive Hormones Profile in High Fat Diet Induced Obese Rats

Ficus asperifolia (Moraceae), is a plant used as fertility booster. We investigated the effects of F. asperifolia extracts on sex hormones profile in high-fat diet (HFD)‑induced estrus cycle disturbances in rats. Female Wistar rats were fed either with HFD (n=161) or standard diet (n=8) for 10 weeks. After this period, 70 obese rats with abnormal estrus cycle were distributed into 14 groups of 5 animals each and treated for one and four weeks with distilled water (10 mg kg-1), Tween-80 (5%-10 mg kg-1), lutenyl (0.88 µg kg-1) and aqueous or methanol extract (100 or 500 mg kg-1) of F. asperifolia. At the end of each period, plasmatic estradiol and progesterone levels were determined. Acute toxicity parameters were also evaluated. HFD impaired reproductive hormones profile and estrous cycle after 10 weeks of treatment.F. asperifolia improved reproductive hormone profile by significantly increasing the plasmatic estradiol and progesterone levels. For instance, the plasmatic estradiol and progesterone levels were significantly increased (p<0.05-0.01) in rats treated with the aqueous (100 mg kg-1, four-weeks; 500 mg kg-1, one-week) or methanol (100 and 500 mg kg-1, four-weeks) extract of F. asperifolia. No toxic effects of F. asperifolia extracts were recorded. Our data support the traditional use of F. asperifolia as fertility enhancer

Evaluation of in vitro uterotonic activities of fruit extracts of Ficus asperifolia in rats,” Evidence-Based Complementary and Alternative Medicine

The aim of the present study was to determine the uterotonic activities of Ficus asperifolia and investigate its mechanism. The effects of aqueous and methanol extracts of the dried fruits of F. asperifolia (0.05-1.60 mg mL −1 ) were evaluated on estrogenized isolated rat uterus in the presence and absence of atropine (1.73-55.27 nM), pyrilamine maleate (1.25 × 10 −3 to 40 × 10 −3 M), indomethacin (0.06 × 10 −5 to 2.00 × 10 −5 M) or hexamethonium (0.66 × 10 −4 to 21.43 × 10 −4 M). Aqueous (EC 50 , 0.36 mg mL −1 ) and methanol (EC 50 , 0.22 mg mL −1 ) extracts as well as oxytocin (EC 50 , 0.02 nM), acetylcholine (EC 50 , 7.87 nM) and histamine (EC 50 , 0.76 nM) evoked concentration-dependent contractions of the uterus. Atropine, pyrilamine maleate and indomethacin concentration dependently blocked the response of the uterus to acetylcholine (IC 50 , 4.82 nM), histamine (IC 50 , 2.49 nM) and oxytocin (IC 50 , 0.07 nM), respectively, and to aqueous extract. Hexamethonium produced graded decreases in oxytocin-induced uterine contractions (IC 50 , 0.37 μM), but did not prevent the contractile effects of the aqueous extract (IC 50 , 9.88 μM). These results suggest that F. asperifolia-induced uterotonic effect is related to the release of prostaglandins and contraction of the myometrial cells through muscarinic, oxytocic and H 1 histamine receptors. These data further give added value to the ethnic use of F. asperifolia for its abortificient and contraceptive properties

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)

Furan derivatives from Lannea kerstingii

Tameko JEM, Chouna JR, Nkeng-Efouet-Alango P, Tapondjou LA, Sewald N. Furan derivatives from Lannea kerstingii. Phytochemistry Letters. 2017;20:282-284.Two new furan derivatives, lannefuran A (1) and lannefuran B (2) were isolated from the stem bark extract of Lannea kerstingii Engl. & K. Krause together with five known compounds, namely: taraxerol, stigmast-4-en-3-one, monoglyceride of hexacosanoic acid, beta-sitosterol and its glucoside. Their structures were determined by means of 1D and 2D NMR, IR, and HR-EI-MS spectra and comparison with the data of known analogues reported in the literature. Lannefuran A (1) exhibited very low antiplasmodial activity against Plasmodium falciparum 3D7

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

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

Tetra-acetylajugasterone a new constituent of Vitex cienkowskii with vasorelaxant activity

Dongmo AB, Nkeng-Efouet PA, Devkota KP, et al. Tetra-acetylajugasterone a new constituent of Vitex cienkowskii with vasorelaxant activity. Phytomedicine. 2014;21(6):787-792.Tetra-acetylajugasterone C (TAAC) was found to be one of the naturally occurring compounds of the Cameroonian medicinal plant Vitex cienkowskii which is responsible for a vasorelaxant activity of an extract of this plant. The evaluation of the underlying mechanisms for the relaxing effect of TAAC was determined using aortic rings of rats and mice. TAAC produced a concentration-dependent relaxation in rat artery rings pre-contracted with 1 mu M noradrenaline (IC50: 8.40 mu M) or 60 mM KCl (IC50: 36.30 mu M). The nitric oxide synthase inhibitor L-NAME (100 mu M) and the soluble guanylate cyclase inhibitor ODQ (10 mu M) significantly attenuated the vasodilatory effect of TAAC. TAAC also exerted a relaxing effect in aorta of wild-type mice (cGKI(+/+); IC50=13.04 mu M) but a weaker effect in aorta of mice lacking cGMP-dependent protein kinase I (cGKI(-/-); IC50=36.12 mu M). The involvement of calcium channels was studied in rings pre-incubated in calcium-free buffer and primed with 1 mu M noradrenaline prior to addition of calcium to elicit contraction. TAAC (100 mu M) completely inhibited the resulting calcium-induced vasoconstriction. The same concentration of TAAC showed a stronger effect on the tonic than on the phasic component of noradrenaline-induced contraction. This study shows that TAAC, a newly detected constituent of Vitex cienkowskii contributes to the relaxing effect of an extract of the plant. The effect is partially mediated by the involvement of the NO/cGMP pathway of the smooth muscle but additionally inhibition of calcium influx into the cell may play a role. (C) 2014 Elsevier GmbH. All rights reserved