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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]cyclohexan-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 μg/mL) with selectivity index higher than 10-fold (SI = 63.4) and moderate leishmanicidal activity (IC50 = 12.17 μg/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.

Two new hydralazine hydrochloride-derived Schiff bases: (E)-1-(Phthalazin- 1-yl)-1-[(Pyridin-2-yl)Ethylidene]Hydralazine (PPEH), and 1-[2-(1-(pyridine- 3-yl)ethylidene)hydrazinyl]phthalazine (PEHP), were synthesized and partially characterized by spectroscopic and crystallographic methods including IR and X-ray. The single-crystal X-ray diffraction (SCXRD) analysis of PEHP indicates that the hydralazine moiety of both ligands possesses the exocyclic C=N bond. Both, PPEH and PEHP were tested as antimicrobials and antiparasites. Just PEHP could be considered as slightly antiplasmodial and antibacterial agent. In effect, PPEH showed low antimicrobial activity against one bacterial strain with Minimum Inhibitory Concentration (MIC) value of 250 μg/ml while PEHP showed very interesting activity against 18 out of 19 bacterial strains with MIC of 31.25 - 250 μg/ml compared to the standard drug, amoxicillin. PPEH and PEHP showed higher reducing activity on ferric ions compared to Vitamin C. On the other hand, both hidrazaline synthetized derivatives showed as better reducing agents than Vitamin C on ferric ions, while again, only the PEHP showed slightly high inhibition of lipid peroxidation using Vitamin C as standard. Regarding their catalase activity, both compounds showed concentration dependent effect, but Vitamin C continued showing a higher stimulatory effect on the enzyme activity. Additionally, while PPEH showed less than 80% inhibition in the preliminary antiplasmodial assay and so was not considered for the dose-response studies, PEHP displayed an inhibition percentage of 83.60% and 50% Inhibitory Concentration (IC50) value of 44.13 μg/mL compared to the standard drug, artemisinin and was classified as slightly active.

One new ent-pimarane-type diterpenoid (1), along with 10 known compounds, were isolated from the leaves of Croton oligandrus. Compounds 2 and 3 are reported for the first time from this species. The extract and some of the isolates were tested in vitro for their inhibitory properties toward urease and butyrylcholinesterase enzymes, as well as DPPH radical scavenging potency, respectively. Compound 6 (IC50 = 29.2 μM) was the most active on urease, while compound 4 (IC50 = 18.2 μM) showed the best inhibitory activity against butyrylcholinesterase. The new isolate, compound 1, with an IC50 value of 39.4 μM revealed potent antioxidant activity.

Two novel Schiff bases, 3-[1-(2-(phthalazin-1-yl)hydrazono)ethyl)-1,3-oxa- zinane (PHEO) and 2-[(2-(phthalazin-1-yl)hydrazono)methyl]phenol (PHMP), derived from hydralazine hydrochloride, an effective drug against hypertension, were synthesized and characterized by spectroscopic methods, Infrared (IR), Proton Nuclear Magnetic Resonance (1H NMR) and Carbon-13 Nuclear Magnetic Resonance (13C NMR). PHEO showed low antimicrobial activity against one bacterial strain with MIC value of 250 μg/ml while PHMP showed interesting activity against 4 bacterial strains with MIC of 31.25 - 250 μg/ml compared to the standard drug, amoxicillin. PHEO and PHMP showed higher reducing activity on ferric ions compared to Vitamin C. On lipid peroxidation, PHEO showed higher inhibition while PHMP showed lower inhibition compared to Vitamin C. Both compounds presented lower stimulating effect and lower catalase activity compared to the standard Vitamin C. PHEO and PHMP showed less than 80% inhibition in the preliminary antiplasmodial assay and so were not considered for the dose-response studies.

The chemical investigation of the CH2Cl2/MeOH (1:1) extract of the trunk bark and leaves of Baphia leptobotrys Harms (Fabaceae) led to the isolation of nineteen compounds (1–19). Their structures were elucidated based on the analysis of their NMR and MS data. Except for compounds 3–5, 14 and 15, all the isolated compounds are reported from the genus Baphia for the first time. Furthermore, compounds 8, 10, 16, 17 are isolated from the Fabaceae family for the first time. The crude extract and isolated compounds were screened in vitro for their antileishmanial activity against Leishmania donovani 1S (MHOM/SD/62/1S) promastigotes and cytotoxicity towards Raw 264.7 macrophage cells. The crude extract of B. leptobotrys exhibited moderate activity (IC50 = 63.40 μg/mL). Amongst the tested compounds, ergosterol peroxide (9) and germanicol caffeoyl ester (8) exhibited good activity with IC50 values of 9.43 and 10.24 μM, respectively and showed acceptable selectivity towards macrophage cells (SI > 3.85). The chemophenetic significance of these compounds is also discussed.

Two previously undescribed ceramides, named celtisamide A (1) and B (2), along with 16 known compounds (3-18), were isolated both from the stem bark and roots of Celtis tessmannii Rendle. The isolated compounds were assessed in vitro for their DPPH radical scavenging, antiplasmodial activity as well as their urease and lipoxygenase inhibitory properties. In addition, fractions and extracts were also evaluated for antiplasmodial and cytotoxicity activities against HEK293T. Cis-1-O-methylinositol (17) (IC50 = 14.3 µM) was the most potent inhibitor of urease, while succinic acid (18) (IC50 = 12.9 µM) exhibited the best inhibition against lipoxygenase. Compound 18 (IC50 = 9.5 µM) showed the best DPPH radical scavenging activity. Extracts and fractions exhibited varying degree of antiplasmodial potency with IC50 values ranging from 2.42-100.00 µg/mL, while betulinic acid (7) showed potency with IC50 values ranging from 1.87-2.34 µg/mL against Chloroquine-sensitive (Pf3D7), and Chloroquine-resistant (PfDd2 and PfINDO) strains of Plasmodium falciparum.

There is continuing need for new and improved drugs to tackle malaria, which remains a major public health problem, especially in tropical and subtropical regions of the world. Natural products represent credible sources of new antiplasmodial agents for antimalarial drug development. Endophytes that widely colonize healthy tissues of plants have been shown to synthesize a great variety of secondary metabolites that might possess antiplasmodial benefits. The present study was carried out to evaluate the antiplasmodial potential of extracts from endophytic fungi isolated from Symphonia globulifera against a chloroquine-resistant strain of Plasmodium falciparum (PfINDO). Sixty-one fungal isolates with infection frequency of 67.77% were obtained from the bark of S. globulifera. Twelve selected isolates were classified into six different genera including Fusarium, Paecilomyces, Penicillium, Aspergillus, Mucor, and Bipolaris. Extracts from the 12 isolates were tested against PfINDO, and nine showed good activity (IC50 &lt, 10 &mu, g&middot, mL&minus, 1) with three fungi including Paecilomyces lilacinus (IC50 = 0.44 &mu, 1), Penicillium janthinellum (IC50 = 0.2 &mu, 1), and Paecilomyces sp. (IC50 = 0.55 &mu, 1) showing the highest promise. These three isolates were found to be less cytotoxic against the HEK293T cell line with selectivity indices ranging from 24.52 to 70.56. Results from this study indicate that endophytic fungi from Symphonia globulifera are promising sources of hit compounds that might be further investigated as novel drugs against malaria. The chemical investigation of active extracts is ongoing.

Continued interest in the chemistry of Ficus spp. led to the investigation of the figs and the roots of Ficus thonningii Blume. Two new flavonoids, thonningiol ( 1 ) and thonningiisoflavone ( 2 ) along with nineteen known compounds were isolated. β -Isoluteone ( 13 ) was isolated here for the first time from a natural source. Their structures were elucidated on the basis of spectroscopic evidence. Interestingly, thonningiisoflavone ( 2 ) and hydroxyalpinumisoflavone ( 21 ) showed strong DPPH radical scavenging activity with IC 50 = 65.50 μM and 68.20 μM respectively compared to the standard BHA with IC 50 = 44.20 μM. The methanolic extract of figs, taxifolin ( 14 ), conrauiflavonol ( 17 ) and shuterin ( 19 ) exhibited moderate antimicrobial activity against six micro-organisms with MIC below 1.5 mg/mL.

As part of our efforts towards identifying and subsequently developing lead compounds from medicinal plants of Cameroon to combat neglected tropical diseases, we embarked to phytochemically investigate Enantia chlorantha (Syn. Annickia chlorantha). The rationale for choosing this plant is its numerous uses in folk medicine in Cameroon and other parts of Africa. In Cameroon the quaternary protoberberine alkaloids, columbamine (2), palmatine (3) and jatrorrizine (4) have been isolated from the stem back and combined to produce a phytomedicine (HEPAZOR®) used in the treatment of viral hepatitis. An alkaloidal extraction of the methanolic extract of the stem bark of the plant was carried-out and this afforded yellow amorphous solids whose structure was obtained using routine nuclear magnetic resonance spectroscopy (NMR), high pressure liquid chromatography coupled to an electrospray mass spectrometer (HPLC-ESI-MS) and comparison with literature. The compound was identified as pseudopalmatine (1), a quaternary protoberberine alkaloid. Preliminary screening of the compound on both adult and juvenile worms of Onchocerca ochengi, a close relative of Onchocerca volvulus, the parasite responsible for human onchocerciasis (river blindness), showed that compound (1) was inactive at a concentration of 500 μg/mL on the adult worms, but inhibited microfilariae motility completely at this same concentration and by 50 % at 250 μg/mL and was thus considered active. While this work to the best of our knowledge constitutes the first report on the anti-onchocercal activity of quaternary protoberberine alkaloids in general and pseudopalmatine (1) in particular isolated from E. Chlorantha, it has however opened a window for further investigation of the anti-onchoceral activity of this class of compounds. Key words: anti-onchocercal, pseudopalmatine, alkaloid, Enantia chlorantha

Phytochemical investigation of the stem bark and leaves of Hymenostegia afzelii resulted in the isolation of three new flavonoids, named afzelin A-C (1-3), together with five known compounds: 7,6-(2 '',2 ''-dimethylpyrano)-3,5,4'-trihydroxyflavone, apigenin, 3-O-alpha-L-rhamnopyranosylcincholic acid, 3-O-beta-D-glucopyranosylcincholic acid, and dodecanoic acid 1,1'-[(1S)-1-(hydroxymethyl)-1,2-ethanediyl] ester. The structures of 1-3 were determined by means of spectroscopic methods. Compounds 1-3 were tested in vitro for their preliminary cytotoxicity using the Artemia salina assay. (C) 2011 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.

Phytochemical investigation of the stem bark and the trunk of Chythrantus claneianus led to the isolation of six known compounds named β-sitosterol (1), umbelliferone (2), scopoletin (3), benjaminamide (4), β-sitosterol-3-O-β-D-glucopyranoside (5) and Panconoside B (6). All these compounds were isolated for the first time from this plant species. The chemical structures of isolates were elucidated on the basis of 1 and 2 D-NMR spectra and other spectroscopic techniques including UV–vis, FT-IR, HR-ESIMS and HR-FABMS. The isolates were tested in vitro for their inhibitory properties towards xanthine oxidase enzyme. Compounds 2, 3 and 6 showed weak inhibi-tory activities on the enzyme with IC 50 values ranging from 307 µM for com-pound 6 to 475 µM for compound 3, while the extract and compounds 1, 4 and 5 showed extremely weak activities with inhibition percentage less than 50%.

Phytochemical investigation of the stem bark and fruits of Dialium excelsum led to the isolation of a new triterpenoid, named dialiumoside (1), together with twelve known compounds (2-13). The structure of the new compound as well as those of the known compounds were established by means of spectroscopic methods and by comparison with previously reported data. Compounds 1-13 were tested for their cytotoxic activity against the human cervix carcinoma KB-3-1 cells and the related multi drug-resistant P-gp-expressing KB-V1 cells. Compounds 1 and 13 showed weak biological activity in cytotoxicity assays while other compounds were inactive.

Phytochemical investigation of the stem bark and fruits of Dialium excelsum led to the isolation of a new triterpenoid, named dialiumoside (1), together with twelve known compounds (2 - 13). The structure of the new compound as well as those of the known compounds were established by means of spectroscopic methods and by comparison with previously reported data. Compounds 1 - 13 were tested for their cytotoxic activity against the human cervix carcinoma KB-3-1 cells and the related multi drug-resistant P-gp-expressing KB-V1 cells. Compounds 1 and 13 showed weak biological activity in cytotoxicity assays while other compounds were inactive.