Pepin Alango Nkeng-Efouet

Antibacterial endiandric acid derivatives from Beilschmiedia anacardioides.

Three endiandric acid derivatives, beilschmiedic acids A, B and C were isolated from the stem bark of Beilschmiedia anacardioides together with the known beta-sitosterol. Their structures were established by means of modern spectroscopic techniques. The relative configuration of compound 1 was determined by single crystal X-ray analysis. The antibacterial activities of compounds A,B,C were evaluated in vitro against five strains of microbes. Compound C showed strong activity against Bacillus subtilis, Micrococcus luteus and Streptococcus faecalis (MICs below 23 microM). This Compound was more active than the reference antibiotic ampicillin against B. subtilis and M. luteus.

Pentacyclic triterpenoids and ceramide mediate the vasorelaxant activity of Vitex cienkowskii via involvement of NO/cGMP pathway in isolated rat aortic rings.

ETHNOPHARMACOLOGICAL RELEVANCE Vitex cienkowskii Kotschy & Peyritsch is a deciduous tree, prescribed by Cameroonian traditional healers as one of the most popular plant widely used in many disorders including cardiovascular diseases. The preliminary pharmacological studies carried out on Vitex cienkowskii showed its vasorelaxant activities on guinea-pig aortic rings. AIM OF THE STUDY The present work evaluated the vasorelaxant activity of extract and isolated compounds from Vitex cienkowskii. MATERIALS AND METHODS Rat aortic rings were used to evaluate the in vitro vascular effect of the extract. The antioxidant activity was determined by measuring the reduction of the free radical 1,1-diphenyl-1-picryl-hydrazyl (DPPH). RESULTS Vitex cienkowskii induced significant relaxation in a concentration- and endothelium-dependent manner (EC(50)=12.12 μg/ml, CH(2)Cl(2)-MeOH, 1:1) and did not produce a vasorelaxant effect on contraction evoked by KCl (60 mM). In order to determine its mode of action, Vitex cienkowskii-induced relaxant effect was evaluated in the presence of indomethacin (10 μM), L-NAME (100 μM), ODQ (1 μM) and SQ22356 (100 μM). Relaxation was significantly blocked by L-NAME and ODQ. These results indicate that Vitex cienkowskii-mediated relaxation is endothelium dependent, probably due to NO release, and the consequent activation of vascular smooth muscle soluble guanylate cyclase (sGC), a signal transduction enzyme that forms the second messenger cGMP. Bio-guided study of Vitex cienkowskii allowed the isolation of the known pentacyclic triterpenoids and a ceramide. It is the first report of salvin A, maslinic acid and a ceramide from Vitex cienkowskii. The activity induced by these compounds indicated that they may be partly responsible for the vasorelaxant effect of the plant extract. A dose of 40 mg/kg of CH(2)Cl(2)-MeOH (1:1) extract administered intravenously induced a decrease of mean arterial pressure but did not affect the heart rate. Moreover the plant extracts were found to be highly active in the DPPH radical scavenging assay. CONCLUSION Vitex cienkowskii extract possesses antioxidant property, vasorelaxing, and hypotensive effect linked to the endothelium related factors, where nitric oxide is involved.

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.

Antinociceptive effects of the aqueous and methanol extracts of the leaves of Pittosporum mannii Hook. F. (Pittosporaceae) in mice

ETHNOPHARMACOLOGICAL RELEVANCE Pittosporum mannii (Pittosporaceae) is used in Africa traditional medicine to treat various ailments including pain and inflammation. AIM OF THE STUDY The present work was undertaken to evaluate the antinociceptive effects of the aqueous (AEPM) and methanol (MEPM) extracts from the leaves of Pittosporum mannii. METHODS High performance liquid chromatography coupled with mass spectrometry (LCMS) was used for the phytochemical analysis of AEPM prepared as decoction and MEPM prepared as cold maceration. The in vitro cytotoxicity of AEPM and MEPM were evaluated on Artemia salina larvae. AEPM and MEPM antinociceptive effects were evaluated at the doses of 35, 75, 150 and 300mg/kg given orally, against pain induced by acetic acid, formalin, hot plate, capsaicin and glutamate. The rota rod test was also performed at the same doses. To determine the mechanism of action of these extracts, their antinociceptive effects were tested in animals pretreated with yohimbine (α2-adrenergic antagonist), atropine (muscarinic antagonist) or naloxone (an opioids antagonist). RESULT The LCMS analysis showed that both extracts contain pittovidoside and 1-O-rhamnopyranosyl-23-acetoxyimberbic acid 29-methyl ester, the aqueous extract being more concentrated. Oral administration of both extracts significantly reduced pain symptoms induced by acetic acid, formalin, capsaicin, glutamate and hot plate. The antinociceptive effect of AEPM was significantly inhibited by yohimbine, atropine and naloxone while these inhibitors tend to potentiate the activity of MEPM. Both extracts have no effect on Rota rod test. AEPM and MEPM showed respective LC50 of 2.44 and 0.70mg/ml on Artemia larvae and were therefore, considered non-toxic. CONCLUSION These results indicate that AEPM and MEPM possesses analgesic effects with different mechanism of action. Although effects of both extracts may involve TRPV1 receptors and glutamatergic pathway, AEPM may in addition, interact with alpha-adrenergic, muscarinic and opioidergic pathways that are not involve in the effects of MEPM.

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

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.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.

High fat diet-induced estrus cycle disruption: effects of Ficus asperifolia

Abstract Background: Ficus asperifolia (L) Hook. Ex Miq (Moraceae) fruits are used in Cameroonian traditional medicine to cure some cases of infertility in women. This study determines the mechanism of alleviating effect of the plant extracts on rat infertility induced by a high fat diet (HFD). Methods: Obesity was reached by feeding female rats with a HFD for 10 weeks. Vaginal smear was observed daily for 3 weeks after animals were obese. Then, 70 animals with abnormal estrus cyclicity were selected and partitioned into two sets of 35 animals. Each set was further divided into seven groups of five rats. These obese rats with disrupted estrus cyclicity were orally administered the aqueous and methanolic extracts (100 and 500 mg/kg), distilled water (10 mL/kg), 5% Tween 80 (10 mL/kg) or lutenyl (0.8 µg/kg) once a day for 1 week (set I) or 4 weeks (set II). Estrus cyclicity, body weight gain, hematocrit, lipid profile, ovarian, uterine and hepatic growth indices were determined at the end of each treatment. Results: HFD increased the body weight of the animals by 27% and disrupted the estrus cyclicity by 98.44%. Aqueous extract (100 mg/kg) of F. asperifolia given for 1 week corrected 40% of the irregular estrus cycle and this percentage increased to 80% as the treatment progressed to 4 weeks. F. asperifolia-treated obese rats (mostly with the aqueous extract at 100 mg/kg) showed a significant decrease (p<0.001) in the total plasma cholesterol and low density lipoprotein (LDL) cholesterol level and a significant increase (p<0.001) in high density lipoprotein (HDL) cholesterol. F. asperifolia has bioactive agents that may maintain conducive conditions for reproduction in obese female rats. Conclusions: Our data support the anecdotal claims of F. asperifolia in folk medicine to cure some cases of infertility in women.

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

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 1μM noradrenaline (IC50: 8.40μM) or 60mM KCl (IC50: 36.30μM). The nitric oxide synthase inhibitor l-NAME (100μM) and the soluble guanylate cyclase inhibitor ODQ (10μM) significantly attenuated the vasodilatory effect of TAAC. TAAC also exerted a relaxing effect in aorta of wild-type mice (cGKI(+/+); IC50=13.04μM) but a weaker effect in aorta of mice lacking cGMP-dependent protein kinase I (cGKI(-/-); IC50=36.12μM). The involvement of calcium channels was studied in rings pre-incubated in calcium-free buffer and primed with 1μM noradrenaline prior to addition of calcium to elicit contraction. TAAC (100μM) 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.