Cytotoxic clerodane diterpenoids from the roots of Casearia barteri Mast.

A study of diterpenoids as active ingredients against cancer from the active roots extract of Casearia barteri Mast. (IC50 = 1.57 µg mL-1) led to the isolation of six new clerodane diterpenoids, named as barterins A-F (1-6) alongside seven known compounds, caseamembrin A, caseamembrin E, casearlucin A, graveospene G, N-trans-feruloyltyramine, N-cis-feruloytyramine and sitosterol-3-O-ß-D-(6-O-palmitoyl)-glucopyranoside. Their structures were elucidated based on NMR spectroscopic data and mass spectrometry. The absolute configurations of 1-6 were established by the time-dependent density functional theory (TDDFT), electronic circular dichroism (ECD) calculations and experimental data analysis. The cytotoxic effects of compounds 1-6 were evaluated against a human cervix carcinoma cell line KB-3-1. Barterins A-D (1-4) showed cytotoxic effects against the KB-3-1 cell line with IC50 values ranging from 1.34-4.73 µM.

In Vitro and Molecular Docking Evaluation of the Anticholinesterase and Antidiabetic Effects of Compounds from Terminalia macroptera Guill. & Perr. (Combretaceae).

Alzheimer's disease (AD) and diabetes are non-communicable diseases with global impacts. Inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are suitable therapies for AD, while α-amylase and α-glucosidase inhibitors are employed as antidiabetic agents. Compounds were isolated from the medicinal plant Terminalia macroptera and evaluated for their AChE, BChE, α-amylase, and α-glucosidase inhibitions. From 1H and 13C NMR data, the compounds were identified as 3,3'-di-O-methyl ellagic acid (1), 3,3',4'-tri-O-methyl ellagic acid-4-O-ß-D-xylopyranoside (2), 3,3',4'-tri-O-methyl ellagic acid-4-O-ß-D-glucopyranoside (3), 3,3'-di-O-methyl ellagic acid-4-O-ß-D-glucopyranoside (4), myricetin-3-O-rhamnoside (5), shikimic acid (6), arjungenin (7), terminolic acid (8), 24-deoxysericoside (9), arjunglucoside I (10), and chebuloside II (11). The derivatives of ellagic acid (1-4) showed moderate to good inhibition of cholinesterases, with the most potent being 3,3'-di-O-methyl ellagic acid, with IC50 values of 46.77 ± 0.90 µg/mL and 50.48 ± 1.10 µg/mL against AChE and BChE, respectively. The compounds exhibited potential inhibition of α-amylase and α-glucosidase, especially the phenolic compounds (1-5). Myricetin-3-O-rhamnoside had the highest α-amylase inhibition with an IC50 value of 65.17 ± 0.43 µg/mL compared to acarbose with an IC50 value of 32.25 ± 0.36 µg/mL. Two compounds, 3,3'-di-O-methyl ellagic acid (IC50 = 74.18 ± 0.29 µg/mL) and myricetin-3-O-rhamnoside (IC50 = 69.02 ± 0.65 µg/mL), were more active than the standard acarbose (IC50 = 87.70 ± 0.68 µg/mL) in the α-glucosidase assay. For α-glucosidase and α-amylase, the molecular docking results for 1-11 reveal that these compounds may fit well into the binding sites of the target enzymes, establishing stable complexes with negative binding energies in the range of -4.03 to -10.20 kcalmol-1. Though not all the compounds showed binding affinities with cholinesterases, some had negative binding energies, indicating that the inhibition was thermodynamically favorable.

Evaluation of anti-quorum sensing and antibiofilm effects of secondary metabolites from Gambeya lacourtiana (De Wild) Aubr. & Pellegr against selected pathogens.

BACKGROUND: Microbial infections cause serious health problems especially with the rising antibiotic resistance which accounts for about 700,000 human deaths annually. Antibiotics which target bacterial death encounter microbial resistance with time, hence, there is an urgent need for the search of antimicrobial substances which target disruption of virulence factors such as biofilm and quorum sensing (QS) with selective pressure on the pathogens so as to avoid resistance. METHODS: Natural products are suitable leads for antimicrobial drugs that can inhibit bacterial biofilms and QS. Twenty compounds isolated from the medicinal plant Gambeya lacourtiana were evaluated for their antibiofilm and anti-quorum sensing effects against selected pathogenic bacteria. RESULTS: Most of the compounds inhibited violacein production in Chromobacterium violaceum CV12472 and the most active compound, Epicatechin had 100% inhibition at MIC (Minimal Inhibitory Concentration) and was the only compound to inhibit violacein production at MIC/8 with percentage inhibition of 17.2 ± 0.9%. Since the bacteria C. violaceum produces violacein while growing, the inhibition of the production of this pigment reflects the inhibition of signal production. Equally, some compounds inhibited violacein production by C. violaceum CV026 in the midst of an externally supplied acylhomoserine lactone, indicating that they disrupted signal molecule reception. Most of the compounds exhibited biofilm inhibition on Staphyloccocus aureus, Escherichia coli and Candida albicans and it was observed that the Gram-positive bacteria biofilm was most susceptible. The triterpenoids bearing carboxylic acid group, the ceramide and epicatechin were the most active compounds compared to others. CONCLUSION: Since some of the compounds disrupted QS mediated processes in bacteria, it indicates that this plant is a source of antibiotics drugs that can reduce microbial resistance.

Polyoxygenated Stigmastane-Type Steroids from Vernonia kotschyana Sch. Bip. ex Walp. and Their Chemophenetic Significance.

Four polyoxygenated stigmastanes (1-4) alongside known analogues (7-8) and flavonoids (5-6) were isolated from a dichloromethane/methanol (1:1, v/v) extract of the whole plant of Vernonia kotschyana Sch. Bip. ex Walp. (Asteraceae). Their structures were determined by means of spectroscopic and spectrometric analysis. The relative stereochemistry of the new compounds was established and confirmed via biosynthesis evidence and cyclization of 1 under acidic conditions. A plausible biosynthetic pathway to the new compounds and the chemophenetic significance of the isolated constituents were also discussed. The crude extract, fractions, and compounds (1-3) were assessed for their antibacterial activity against five highly prevalent bacterial strains. The fractions and compounds showed low to moderate activity with minimal inhibitory concentrations (MICs) > 125 µg/mL.

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

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 3.56 µg/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 0.63 µg/mL. All extracts, fractions, and isolated compounds demonstrated no cytotoxicity against Raw cell lines with CC50 > 250 µg/mL. In addition, the most active extract on both strains of P. falciparum was nontoxic in vivo, with a LD50 greater than 2000 and 5000 mg/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.

UPLC-QToF-ESI-MS identification and anthelmintic activity of Mitragyna inermis (Willd.) Kuntze (Rubiaceae).

Medicinal plants attract the attention of many researchers to find natural and safe remedies for various resistant diseases. Leaves of Mitragyna inermis are widely used in traditional veterinary medicine for the treatment of gastrointestinal strongyles of small ruminants. The aim of the current study is to estimate the antioxidant, anthelmintic and the larval toxicity of the aqueous and hydroethanolic extracts of this plant in addition to the hexane, dichloromethane and ethanol fractions of the hydroethanolic extract. Investigation of the most active extract using Ultra Performance Liquid Chromatography coupled with Quadrupole Time-of-Flight Electrospray Ionization Mass Spectrometry (UPLC-QToF-ESI-MS). Both plant extracts showed good antioxidant activity by scavenging the 2,2'-diphényl-1-picrylhydrazyl (DPPH) radical and reducing the ferric ion. Similarly, they were no-toxic to Artemia salina larvae (CL50 > 0.1 µg/mL). Also, they significantly reduced larval migration and motility of Haemonchus contortus adult worms (p < 0.001). The hexane, dichloromethane and ethanolic fractions of the hydroethanolic extract showed low activity compared to crude extracts except for the hexane fraction on H. contortus adult worms (p < 0.001) while it showed a poor result on larvae. It thus appears that the anthelmintic activity of the extract may be linked to the synergistic action of these compounds. The UPLC-QToF-ESI-MS analysis revealed the tentative identification of 15 compounds including 7 alkaloids. The results of the present study confirm the anthelmintic activity of M. inermis in traditional veterinary medicine.

Constituents of the Stem Bark of Symphonia globulifera Linn. f. with Antileishmanial and Antibacterial Activities.

The chemical investigation of the n-hexane fraction from the methanol extract of the stem bark of Symphonia globulifera Linn f., which displayed good in vitro activity against Leishmania donovani NR-48822 promastigotes (IC50 43.11 µg/mL), led to the isolation of three previously unreported polyprenylated benzophenones, guttiferone U (1), V (2)/W (3), and a new tocotrienol derivative named globuliferanol (4), along with 11 known compounds (5-15). Their structures were elucidated based on their NMR and MS data. Some isolated compounds were assessed for both their antileishmanial and cytotoxic activities against L. donovani and Vero cells, respectively. Guttiferone K (5) exhibited the best potency (IC50 3.30 µg/mL), but with low selectivity to Vero cells. The n-hexane fraction and some compounds were also assessed in vitro for their antibacterial activity against seven bacterial strains. All the samples exhibited moderate to potent antibacterial activity (MICs ≤ 15.6 µg/mL) against at least one of the tested strains.

Constituents of the Stem Bark of Trichilia monadelpha (Thonn.) J. J. De Wilde (Meliaceae) and Their Antibacterial and Antiplasmodial Activities.

The chemical investigation of the EtOH extract from the stem bark of Trichilia monadelpha (Thonn.) J. J. De Wilde afforded two new limonoids (1 and 2): 24-acetoxy-21,25-dihydroxy-21,23-epoxytirucall-7-en-3-one (1) and (6R)-1-O-deacetylkhayanolide E (2), together with eleven known compounds (3-13), including additional limonoids, flavonoids, triterpenoids, steroids, and fatty acid. Their structures were determined using 1D- and 2D-NMR experiments, ESI mass spectrometry, and single crystal X-ray diffraction analysis. The antibacterial and antiplasmodial activities of the extracts, sub-extracts, fractions, and some of the isolated compounds were evaluated in known pathogenic strains, including Staphylococcus aureus and Plasmodium falciparum. Fraction E (n-Hex/EtOAc 30:70, v/v) showed significant activity against S. aureus ATCC 25923 with a MIC value of 3.90 µg/mL, while one of its constituents (epicatechin (9)) exhibited significant activity with MIC values of 7.80 µg/mL. Interestingly, grandifotane A (6) (IC50 = 1.37 µM) and khayanolide D (5) (IC50 = 1.68 µM) were highly active against the chloroquine-sensitive/sulfadoxine-resistant plasmodium falciparum 3D7 strain, unlike their corresponding plant extract and fractions.

Coumarinolignoid and Indole Alkaloids from the Roots of the Hybrid Plant Citrus × paradisi Macfad (Rutaceae).

A phytochemical investigation of the roots of Citrus × paradisi Macfad. (Rutaceae) led to the isolation of two new compounds, namely 1-formyl-5-hydroxy-N-methylindolin-1-ium (1) and decyloxycleomiscosin D (2), along with ten known compounds: 1,1-dimethylpyrrolidin-1-ium-2-carboxylate (3), furan-2,3-diol (4), 5-methoxyseselin (5), umbelliferone (6), scopoletin (7), citracridone I (8), citracridone II (9), citracridone III (10), limonin (11) and lupeol (12). The structures were determined through the comprehensive spectroscopic analysis of 1D and 2D NMR and EI- and ESI-MS, as well as a comparison with the published data. Notably, compounds 3 and 4 from the genus Citrus are reported here for the first time. In addition, the MeOH extract of the roots and compounds 1-7 were screened against the human adenocarcinoma alveolar basal epithelial cell line A549 and the Caucasian prostate adenocarcinoma cell line PC3 using the MTT assay. While the extract showed significant activity, with IC50 values of 35.2 and 38.1 µg/mL, respectively, compounds 1-7 showed weak activity, with IC50 values of 99.2 to 250.2 µM and 99.5 to 192.7 µM, respectively.

Crotofoligandrin, a new endoperoxide crotofolane-type diterpenoid from the twigs of Croton oligandrus Pierre ex. Hutch (Euphorbiaceae).

Crotofoligandrin (1), a new endoperoxide crotofolane-type diterpenoid was isolated from the dichloromethane/methanol (1:1) extract of the twigs of Croton oligandrus Pierre Ex Hutch along with thirteen known secondary metabolites including 1-nonacosanol (2), lupenone (3), friedelin (4), ß-sitosterol (5), taraxerol (6), (-)-hardwickiic acid (7), apigenin (8), acetyl aleuritolic acid (9), betulinic acid (10), fokihodgin C 3-acetate (11), D-mannitol (12), scopoletin (13) and quercetin (14). The structures of the isolated compounds were determined based on their spectroscopic data. The crude extract and the isolated compounds were assessed in vitro for their antioxidant, lipoxygenase, butyrylcholinesterase (BChE), urease and glucosidase inhibitory potentials. Compounds 1-3, and 10 displayed activities on all the performed bioassays. All the tested samples showed strong to significant antioxidant activity with compound 1 being the most potent (IC50 39.4 µM).

Two new secondary metabolites with antibacterial activities from Conyza aegyptiaca (Asteraceae).

The bio guided fractionation of the dichloromethane/methanol (1:1) crude extract of the air-dried whole plant of C. aegyptiaca led to the isolation of one new flavone derivative designated conyflavone (1) and one new clerodane diterpene type designated conyclerodane (2) along with five known compounds including two flavonoids Gardenin C (3), chrysosplenetin (4) and two steroids glucoside of ß-sitosterol (5), the mixture of stigmasterol (6) and ß-sitosterol (6') and ent-2b,18,19trihydroxycleroda-3,13-dien-16,15-olide (7). The structures were established by spectroscopic methods including IR, 1D and 2D NMR in conjunction with mass spectroscopy and by comparison to data of related compounds described in literature. The stereocentres in compound 2 were determined by SC-XRD analysis. Crude extract as well as fractions and pure compounds were evaluated in vitro for their antibacterial activities against four pathogenic and two clinical isolate strains using microdilution methods. Extracts and compounds displayed a moderate antibacterial activity with MIC values ranging from 125 to 500 µg/mL.

Antibacterial constituents of Rumex nepalensis spreng and its emodin derivatives.

The CH2Cl2-MeOH (1:1) extract of roots of Rumex nepalensis (Polygonaceae) displayed significant antibacterial activity against five bacterial strains with MICs (62.5-31.2 µg.mL-1). The EtOAc soluble fraction displayed a significant activity against the same strains with MICs (31.2-3.9 µg.mL-1). The purification of the EtOAc fraction yielded one new phenylisobenzofuranone derivative, berquaertiide (1), along with 19 known compounds (2-20). Their structures were elucidated based on the analysis of their NMR and MS data. All the isolated compounds were assessed for their antibacterial activity. Compound 2 was the most active against all the tested strains (15.7 to 1.9 µg.mL-1), while compounds 3-7 displayed good activities on at least one of the tested strains. In addition, seven analogues (21-27) of compound 2 were prepared and further assessed for their antibacterial activity. Compounds 26 and 27 were most active than 2 against Salmonella enterica and Klebsiella pneumoniae with MIC (125 and 15.6 µg.mL-1, respectively).

One new constituent from the stem bark of Chrysophyllum lacourtianum De Wild. (sapotaceae).

The phytochemical investigation of the methanol extract of the stem bark of Chrysophyllum lacourtianum led to the isolation and characterization of one new secondary metabolite, lacourtianal (1), together with eight known compounds. Compounds 2; 3; 5; 6; 7 and 9 were reported for the first time from Chrysophyllum genus. The structures of compounds 1-9 were elucidated on the basis of 1 D and 2 D NMR spectroscopic and mass spectrometric data as well as comparison with the literature. The antibacterial activity of the methanol extract, fractions and compounds 1-9 were evaluated against bacterial strains. The methanol extract exhibited moderate activity against Staphylococcus aureus NR4674 with MIC values of 500 µg/mL. The n-hexane fraction showed moderate activity against Staphylococcus aureus (ATCC 43300 and ATCC 25923) with MIC values of 125 µg/mL and ursolic acid (5) exhibited strong activity against Enterobacter aerogenes CPC and Escherichia coli ATCC 25322 with MIC values of 7.8 and 3.9 µg/mL respectively.

Bioactive Arylnaphthalide Lignans from Justicia depauperata.

Eleven previously undescribed arylnaphthalide lignans (1-11) together with seven known compounds were isolated from the whole plant of Justicia depauperata. The structures of 1-11 were elucidated by spectroscopic analysis and mass spectrometry. Compounds 6 (IC50 = 4.1 µM) and 9 (IC50 = 9.5 µM) displayed cytotoxic activity against the KB-3-1 cervical carcinoma cell line. This report provides an insight into the conformational equilibria occurring in the arylnaphthalide lignan constituents of this plant.

Echinocystic Acid Bidesmoside Saponins from Microglossa afzelii O. Hoffm and Their Cytotoxic Activity against the CAL-27 Oral Squamous Carcinoma Cell Line.

This paper describes eight new triterpenoid saponins, including afzeliioside A (1), four acetylated afzeliiosides as pairs of inseparable regioisomers, called afzeliiosides B/C (2/3) and D/E (4/5), afzeliiosides F-H (6-8), and a known impatiprin C (9), which were isolated from the n-BuOH fraction of the liana of Microglossa afzelii. Their structures were established mainly by extensive spectroscopic analysis, including 1D and 2D NMR, HRFAB-MS, tandem ESI-MS/MS, and chemical methods, as well as a comparison of their spectral data with those of related compounds. All the isolates were screened for their cytotoxic activity against the CAL-27 oral squamous carcinoma cell line. Only compounds 4/5 (EC50 = 36.0 µg/mL (32.7 µM)) exhibited moderate cytotoxic activity. This work presents the first chemical and biological investigation of Microglossa afzelii and reports, for the first time, on the isolation of saponins in the genus Microglossa.

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

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 13.86 µg/mL and 8.18 µg/mL, respectively. Among the tested compounds, wighteone (2) was the most active against P. falciparum 3D7 (IC50 = 24.6 ± 1.5 µM) and Dd2 (IC50 = 11.9 ± 2.4 µM) 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 8.18 µg/mL, respectively. • Wighteone was the most active compound against PfDd2 (IC50 = 11.9 ± 2.4 µM).

Soyauxinine, a New Indolopyridoquinazoline Alkaloid from the Stem Bark of Araliopsis soyauxii Engl. (Rutaceae).

The chemical investigation of the total alkaloid extract (TAE) of the stem bark of Araliopsis soyauxii (Rutaceae) afforded an unreported indolopyridoquinazoline (compound 1) along with nine previously known alkaloids 2-10. In addition, six semi-synthetic derivatives 3a-c, 4b, 5a and 6a were prepared by allylation and acetonidation of soyauxinium nitrate (5), edulinine (3), ribalinine (4) and arborinine (6). The structures and spectroscopic data of five of them are reported herein for the first time. The suggested mechanism for the formation of the new N-allylindolopyridoquinazoline 5a is presented. The structures of natural and derived compounds were determined employing extensive NMR and MS techniques. The absolute configuration of stereogenic centers in compounds 2-4 were determined using NOESY technique and confirmed by the single-crystal X-ray diffraction (SC-XRD) technique. The use of SC-XRD further enabled us to carry out a structural revision of soyauxinium chloride recently isolated from the same plant to soyauxinium nitrate (5). The TAE, fractions, compounds 1-7 and 9, and semi-synthetic derivatives 3a-c, 4b, 5a and 6a were evaluated for their cytotoxic activity towards the cervix carcinoma cell line KB-3-1. No significant activity was recorded for most of the compounds except for 9, which showed moderate activity against the tested cancer cell lines.

Antibacterial flavonoids from the fruits of Macaranga hurifolia.

As part of our search for new secondary metabolites from Macaranga hurifolia Beille, a phytochemical investigation was carried out on the fruits that led to the isolation and characterization of two new prenylated flavonol derivatives named macafolias A (1) and B (2), along with five known compounds. Their chemical structures were established on the basis of extensive analysis of their 1-D and 2-D NMR (1H, 13C, APT, COSY, HSQC and HMBC) in conjunction with mass spectroscopy and by comparison with data from the literature. The in vitro assay of the antibacterial potency of the crude extract, fractions and some pure compounds were evaluated against a wide range of bacteria strains.

Bioguided isolation of antiplasmodial secondary metabolites from Persea americana Mill. (Lauraceae).

The antiplasmodium assay-guided investigation of the roots, stem bark, and leaves of Persea americana Mill. led to the isolation of a new fatty alcohol, perseatriol (1), along with six known compounds (2-7). Their structures were elucidated based on the analysis of their NMR and MS data. All crude extracts and fractions exhibited good antiplasmodial activity on Plasmoduim falciparum 3D7 with IC50 values ranging from 0.76 to 10.5 µg/mL; they also displayed cytotoxicity against HeLa cells with low selectivity indexes (SIs). A preliminary Plasmodium lactate dehydrogenase (pLDH) assay was also performed on the isolated compounds. 9,9'-Di-O-feruloyl-5,5'-dimethoxysecoisolariciresinol (4) turned out to be non-toxic and displayed the best activities on P. falciparum with an IC50 value of 0.05 µM, comparable to the reference drug chloroquine with an IC50 value of 0.03 µM. Furthermore, besides compound 4, this work reports the first isolation of lutein (2) and scopoletin (3) from P. americana. The crude extracts of roots, stem bark, and leaves of P. americana, their fractions and compounds completely suppressed the growth of P. falciparum. The observed activity supports the use of P. americana in folk medicine for the treatment of malaria.

Two new triterpenoid fatty acid esters from Schefflera barteri Harms (Araliaceae)§.

Two new fatty acid esters of triterpenoids (1-2) together with eleven known compounds (3-13) were obtained after investigation of the CH2Cl2-MeOH (1:1) crude extract from the leaves of Schefflera barteri Harms. All these compounds (1-13) were isolated for the first time from this plant among which compounds 3, 4, 6 and 9-13 were also isolated from the genus Schefflera for the first time. The structures of the isolated compounds were elucidated by analyses of their spectroscopic data (1D and 2D NMR, and MS). The antibacterial and cytotoxic activities of crude extracts, fractions and compounds (1, 2, 5, 6, 8 and 9) were investigated against both Gram-negative and Gram-positive bacteria strains as well as on human cervix carcinoma and colon adenocarcinoma cancer cell lines, respectively. They showed weak to significant activity towards the strains and malignant cells used.