Foetidumins A-D, and other chemical constituents from Helichrysum foetidum (L.) Moench (Asteraceae) with antiparasite activity.

The phytochemical investigation of the MeOH and CH2Cl2-MeOH (1:1) extracts from the flowers and twigs of Helichrysumfoetidum (L.) Moench (Asteraceae), which showed antileishmanial and antiplasmodial activities during the preliminary screening, led to the isolation of four undescribed compounds, including two ent-beyer-15-ene-type diterpenoids, foetidumins A (1) and B (2), one flavonoid, foetidumin C (3) and one chalcopyrone, foetidumin D (4). Additionally, fourteen known compounds comprising, two ent-beyer-15-ene-type diterpenoids (5-6), six flavonoids (7-12), two steroids (13-14), three triterpenoids (15-17), and one glyceryl monostearate (18) were also isolated. The chemical structures of foetidumins A-D were fully elucidated by analyses of their spectroscopic data. The structure and the stereochemistry of foetidumin A (1) were confirmed by SC-XRD analyses. Among the tested compounds, foetidumin C (3), erythroxylol A (6), and kaempferol (7) displayed the highest antileishmanial potency with IC50 values of 13.0, 11.8, and 11.1 µM, respectively. Foetidumin C (3) had no cytotoxicity toward Vero cells with the selectivity index > 3.59. Meanwhile, extracts of flowers and twigs had higher activity against Plasmodium falciparum chloroquine-sensitive (Pf3D7) strain with IC50 values of 3.66 and 10.52 µg/mL, respectively.

Curative anti-typhoid effect of Detarium microcarpum Guill. & Perr. (Leguminosae) hydroethanolic extract root bark based-on in vivo and molecular docking analyses.

ETHNOPHARMACOLOGICAL RELEVANCE: Detarium microcarpum is used to treat typhoid fever, a major public health problem, by indigenous population in Africa. Though its preventive activities have been documented, the curative effect is still to be confirmed. AIM OF THE STUDY: This study aimed at evaluating the curative effects of the hydroethanolic extract of Detarium microcarpum root bark on Salmonella typhimurium-induced typhoid in rat and exploring the in-silico inhibition of some bacterial key enzymes. STUDY DESIGN: In vitro antioxydant, in vivo antisalmonella of the extract and in silico molecular docking assay on the isolated compounds were carried out to explore the anti-salmonella effects of Detarium microcarpum. MATERIAL AND METHODS: The in vitro antioxidant properties of the extract were evaluated using DPPH, ABTS and FRAP tests. The anti-salmonella activity of the extract was assessed through feacal sample from Salmonella typhimurium-infected rat cultured in Salmonella-Shigella agar (SS agar) medium. The affinity of isolated compounds (Rhinocerotinoic acid and Microcarposide) from the extract were performed on four key enzymes (Adenylosuccinate lyase, Acetyl coenzyme A synthetase, Thymidine phosphorylase and LuxS-Quorum sensor) using molecular docking simulation to elucidate the molecular level inhibition mechanism. RESULTS: Crude extract of D. microcarpum root bark showed variable activities on DPPH (RSa50: 6.09 ± 1.04 µg/mL), ABTS (RSa50: 24.46 ± 0.27), and FRAP (RSa50: 23.30 ± 0.23). The extract at all the doses exhibited significant healing effect of infected rats, with the complete clearance. The extract restored hematological, biochemical and histological parameters closed to the normal control. The molecular docking results indicates that rhinocerotinoic acid and microcarposide present more affinity to the LuxS-Quorum sensor and Acetyl coenzyme A synthetase protein as compared to the others. CONCLUSION: These results demonstrate potent anti-typhoid activities of the hydroethanolic of Detarium microcarpum root bark extract through antioxidant properties and high inhibitory affinity of its compounds on some bacterial key enzymes that justify its use as traditional medicine to typhoid fever.

Identification of 3,3'-O-dimethylellagic acid and apigenin as the main antiplasmodial constituents of Endodesmia calophylloides Benth and Hymenostegia afzelii (Oliver.) Harms.

BACKGROUND: Endodesmia calophylloides and Hymenostegia afzelii belong to the Guttiferae and Caesalpiniaceae plant families with known uses in African ethno-medicine to treat malaria and several other diseases. This study aimed at identifying antiplasmodial natural products from selected crude extracts from H. afzelii and E. calophylloides and to assess their cytotoxicity. METHODS: The extracts from H. afzelii and E. calophylloides were subjected to bioassay-guided fractionation to identify antiplasmodial compounds. The hydroethanol and methanol stem bark crude extracts, fractions and isolated compounds were assessed for antiplasmodial activity against the chloroquine-sensitive 3D7 and multi-drug resistant Dd2 strains of Plasmodium falciparum using the SYBR green I fluorescence-based microdilution assay. Cytotoxicity of active extracts, fractions and compounds was determined on African green monkey normal kidney Vero and murine macrophage Raw 264.7 cell lines using the Resazurin-based viability assay. RESULTS: The hydroethanolic extract of H. afzelii stem bark (HasbHE) and the methanolic extract of E. calophylloides stem bark (EcsbM) exhibited the highest potency against both Pf3D7 (EC50 values of 3.32 ± 0.15 µg/mL and 7.40 ± 0.19 µg/mL, respectively) and PfDd2 (EC50 of 3.08 ± 0.21 µg/mL and 7.48 ± 0.07 µg/mL, respectively) strains. Both extracts showed high selectivity toward Plasmodium parasites (SI > 13). The biological activity-guided fractionation led to the identification of five compounds (Compounds 1-5) from HasbHE and one compound (Compound 6) from EcsbM. Of these, Compound 1 corresponding to apigenin (EC50 Pf3D7, of 19.01 ± 0.72 µM and EC50 PfDd2 of 16.39 ± 0.52 µM), and Compound 6 corresponding to 3,3'-O-dimethylellagic acid (EC50 Pf3D7 of 4.27 ± 0.05 µM and EC50 PfDd2 of 1.36 ± 0.47 µM) displayed the highest antiplasmodial activities. Interestingly, both compounds exhibited negligible cytotoxicity against both Vero and Raw 264.7 cell lines with selectivity indices greater than 9. CONCLUSIONS: This study led to the identification of two potent antiplasmodial natural compounds, 3,3'-O-dimethylellagic acid and apigenin that could serve as starting points for further antimalarial drug discovery.

Bio-guided isolation of anti-leishmanial natural products from Diospyros gracilescens L. (Ebenaceae).

BACKGROUND: Plants represent an intricate and innovative source for the discovery of novel therapeutic remedies for the management of infectious diseases. The current study aimed at discovering new inhibitors of Leishmania spp., using anti-leishmanial activity-guided investigation approach of extracts from Diospyros gracilescens Gürke (1911) (Ebenaceae), targeting the extracellular (promastigotes) and intracellular (amastigotes) forms of Leishmania donovani. METHODS: The plant extracts were prepared by maceration using H20: EtOH (30:70, v/v) and further fractionated using a bio-guided approach. Different concentrations of D. gracilescens extracts, fractions and isolated compounds were tested in triplicate against L. donovani promastigotes and amastigotes in vitro. The antileishmanial potency and cytotoxicity on RAW 264.7 cells were determined using the resazurin colorimetric assay. The time kill kinetic profile of the most active sample was also investigated. The structures of all compounds were elucidated on the basis of extensive spectroscopic analyses, including 1D and 2D NMR, and HR-ESI-MS and by comparison of their data with those reported in the literature. RESULTS: The hydroethanolic crude extract of D. gracilescens trunk showed the most potent antileishmanial activity (IC50 = 5.84 µg/mL). Further fractionation of this extract led to four (4) fractions of which, the hexane fraction showed the most potent activity (IC50 = 0.79 µg/mL), and seven (07) compounds that exhibited moderate potency (IC50 = 13.69-241.71 µM) against L. donovani. Compound 1-deoxyinositol (7) inhibited the promastigote and amastigote forms of L. donovani with IC50 values of 241.71 µM and 120 µM respectively and also showed the highest selectivity against L. donovani promastigotes (SI > 5.04). To the best of our knowledge, the antileishmanial activity of this compound is being reported here for the first time. The promising hexane fraction showed significant inhibition of parasites growth at different concentrations, but with no evidence of cidal effect over an exposure period of 120 h. CONCLUSIONS: The results obtained indicated that the hydroethanolic extract from the D. gracilescens trunk and the derived hexane fraction have very potent inhibitory effect on cultivated promastigotes and amastigotes of L. donovani parasite. The isolated compounds showed a lesser extent of potency and selectivity. However, further structure-activity-relationship studies of 1-deoxyinositol could lead to more potent and selective hit derivatives of interest for detailed drug discovery program against visceral leishmaniasis.

Experimental and computational studies of an antiplasmodial derivative of allantoin; antimycobacterial essential oil from Cordia batesii WERNHAM (Boraginaceae).

BACKGROUND: Chemical and pharmacological investigations were performed on the stems of Cordia batesii (Boraginaeae); chemical studies included quantum calculations applied on a newly described compound. RESULTS: A new derivative of allantoin (1) named batesiin (2) was characterized. Thirteen other known compounds involving allantoin (1) were either isolated or identified. GC-MS enabled the identification of six compounds from a fraction containing essential oil. MeOH extract and some isolated compounds were tested in vitro against Pf7G8 CQS and Pf Dd2 CQR strains of Plasmodium falciparum; extract disclosed a moderate antiplasmodial activity (IC50 = 50 µg mL-1). Meantime, the CH2Cl2 extract and essential oil fraction were tested on a resistant mycobacterial strain of Mycobacterium tuberculosis; a potent antimycobacterial activity with a MIC = 9.52 µg mL-1 was deduced from essential oil. Density functional theory (DFT) calculations were carried on batesiin (2). Calculated chemical shifts at B3LYP/6-31G(d,p) and MPW1PW91/6-31G+(d,p) showed much better correlations with the experimental data. Time dependent DFT at B3LYP/6-31G+(d,p) displayed a major absorption band 3.01 nm higher than the experimental value. CONCLUSION: Cordia batesii can be considered as promising in search of compounds with antimalarial and antitubercular properties. DFT studies are very helpful when trying to learn more about the spectroscopic insights of a derivative of allantoin (1).

In vitro and in vivo anti-salmonella properties of hydroethanolic extract of Detarium microcarpum Guill. & Perr. (Leguminosae) root bark and LC-MS-based phytochemical analysis.

ETHNOPHARMACOLOGICAL RELEVANCE: Typhoid fever treatment remains a challenge in endemic countries. Detarium microcarpum is traditionally used to manage typhoid. AIM OF THE STUDY: The study aims to explore the efficacy of hydroethanolic extract of Detarium microcarpum root bark in rats infected with salmonella. MATERIAL AND METHODS: The phytochemical profile of the extract was obtained by UHPLC-MS analysis in an attempt of standardization. The in vitro antimicrobial activity was determined using broth dilution method. Salmonella infection was induced by oral administration of S. thyphimurium to immunosuppressed rats. Infected rats were then treated 2 h later with the extract (75, 150 and 300 mg/kg), distilled water (normal and salmonella control) and ciprofloxacin (8 mg/kg) for control. Body weight was monitored and stools were cultured to determine the number of colony-forming units. At the end of treatment, animals were sacrificed, blood and organs were collected for hematological, biochemical and histopathological analyses. RESULTS: Detarium microcarpum extract as well as the isolated compound (rhinocerotinoic acid) exhibited good antimicrobial activity in vitro with bacteriostatic effects. The plant extract significantly (p < 0.05) inhibited the bacterial development in infected animals with an effective dose (ED50) of 75 mg/kg. In addition, the extract prevented body weight loss, hematological, biochemical and histopathological damages in treated rats. CONCLUSION: Detarium microcarpum extract possesses antisalmonella properties justifying its traditional use for the typhoid fever management.

Extracts from Annona Muricata L. and Annona Reticulata L. (Annonaceae) Potently and Selectively Inhibit Plasmodium Falciparum.

The aim of this work was to screen extracts from Annona muricata and Annona reticulata in vitro against Plasmodium falciparum. Crude ethanolic extracts, methylene chloride fractions, aqueous fractions, subfractions and isolated compounds (stigmasterol-3-O-ß-d-glucopyranoside, lichexanthone, gallic acid and ß-sitosterol-3-O-ß-d-glucopyranoside) were tested for cytotoxicity on erythrocytes and Human Foreskin Fibroblasts cells and against the W2 strain of P. falciparum in culture. Results indicated that none of the extracts was cytotoxic at concentrations up to 10 µg/mL. Most of the extracts, fractions and subfractions inhibited the growth of P. falciparum with IC50 values ranging from 0.07 to 3.46 µg/mL. The most potent was the subfraction 30 from A. muricata stem bark (IC50 = 0.07 µg/mL) with a selectivity index of ˃ 142. Subfraction 3 from A. muricata root also exhibited very good activity (IC50 = 0.09 µg/mL) with a high selectivity index (SI ˃ 111). Amongst the isolated compounds, only gallic acid showed activity with IC50 of 3.32 µg/mL and SI > 10. These results support traditional claims for A. muricata and A. reticulata in the treatment of malaria. Given their limited cytotoxicity profile, their extracts qualify as promising starting points for antimalarial drug discovery.

Antimicrobial and antioxidant effects of phenolic constituents from Klainedoxa gabonensis.

Bioassay-guided fractionation of the methanol extract of the stem bark of Klainedoxa gabonensis Pierre ex Engl. (Irvingiaceae) afforded 12 compounds, namely, ellagic acid (1), ellagic acid 3,3'-dimethylether (2), gallic acid (3), methyl gallate (4), lupeol (5), ß-amyrin (7), erythrodiol (8), oleanolic acid (9), betulinic acid (6), hederagenin (10), bayogenin acid (11), and stigmasterol-3-O-ß-d-glucopyranoside (12). Compounds 1-3 and 7-12 were isolated for the first time from this genus. The structures were established on the basis of 1D/2D NMR experiments and mass spectrometric data. Crude extract, fractions (A, B, C and D) and pure compounds were tested for their antimicrobial activity using paper disk agar diffusion assay. The test delivered a range of low to high activities for phenolic compounds 1-4, low or missing activities for terpenoid compounds 5-11, and impressive very high antibacterial/antifungal values for two fractions C and D probably due to synergistic effects of compounds. The broth microdilution assay revealed MICs of 15.4-115.1 µg/mL for phenolic compounds, MICs higher than 1 mg/mL for terpenoids and MICs of 4.5-30.3 µg/mL for fractions C and D. The determination of the radical scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay gave high antioxidant values for the methanol extract and fraction D (IC(50) 10.45 and 5.50 µg/mL) as well as for the phenolic compounds 1-4 (IC(50) 45.50-48.25 mM) compared to the standard 3-t-butyl-4-hydroxyanisole (BHA) (IC(50) 44.20 mM).

A prenylated xanthone with antimicrobial activity from the seeds of Symphonia globulifera.

A prenylated xanthone has been isolated from the seeds of Symphonia globulifera together with the known compounds sitosterol and oleanolic acid. The structure of the new compound was elucidated by spectroscopic methods.