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Malaria is regarded as one of the most lethal diseases. Resistance to artemisinin and its derivatives jeopardises effective malaria treatment. Finding novel antimalarial chemicals is critical given the existing treatment situation. This work aimed to examine the antiplasmodial capabilities of Pseudarthria hookeri fractions and flavonoids in vivo. The fractions and compounds antiplasmodial activity were evaluated on male Swiss albino mice infected with Plasmodium berghei, and on healthy female Swiss albino mice, the crude extract's acute toxicity was assessed. The EtOAc fraction had significant antiplasmodial activity (32.53 percent suppression at 500 mg/kg BW) and considerably prolonged the survival period of infected mice (9.8 days) compared to control mice (7.8 days). Parasitaemia was dramatically reduced (85.01, 59.41, and 70.39 percent), and the mean survival time extended (11.33, 10.00, and 9.33 days) with 15, 20 and 35 mg/kg of quercetin (1), 7-O-benzyl-6-prenylpinocembrin (6) and 6,8-diprenyleriodictyol (11) (isolates of the EtOAc fraction), respectively. BW loss and PCV reduction were also averted. Moreover, at 2500 mg/kg, the crude extract of P. hookeri showed no acute toxicity in mice. LC-MS analysis of the EtOAc fraction enabled the identification of nine flavonoids, with 8 and 11 being the main components. The present investigation confirmed P. hookeri's antiplasmodial action, substantiating its ethnomedicinal application for malaria treatment.

A new flavone derivative named pachypodostyflavone (1), along with 8 known compounds (2–9) and a mixture of β-sitosterol and stigmasterol were isolated from the stem bark of Duguetia staudtii (Annonaceae), based on a bioassay-guided fractionation. Their structures were determined using high-resolution mass spectrometry and NMR spectroscopic data, as well as by comparison with the literature values of their analogs. Selected isolated compounds were evaluated for their in vitro antifilaricidal activities on Onchocerca ochengi microfilariae and adult worms. Inhibition of motility was evaluated spectroscopically on microfilaria and adult male worms. Viability was determined on adult female worms by the MTT/ Formazan assay. Auranofin at 10 µM and 2% DMSO were used as positive and negative controls, respectively. Compounds 1 and 7 showed potent anti-onchocerca activities with 100% activity at 250 µg/mL on both O. ochengi adult male and female worms, while compound 5 displayed 100% activity at 30 µg/mL.

Costunolide, a naturally occurring sesquiterpene lactone, was investigated experimentally and theoret-ically to determine the structural, electronic, spectroscopic, and chemical reactivity properties. As de-duced from a single crystal X-ray diffraction (XRD) analysis, the absolute configurations of the two chiral centres were assigned as (6R,7S). Vibrational frequencies (IR, UV and NMR), electronic properties (HOMO and LUMO), and the molecular structure of costunolide were investigated by DFT calculations using Gaus-sian 09 molecular package at the B3LYP/6-311 ++ G(d,p) level of theory. NMR chemical shifts were calcu-lated from the magnetic shielding tensors obtained through the gauge-independent atomic orbital (GIAO) method, while the UV-vis spectrum was simulated by time dependent-DFT (TD-DFT) calculations. All cal-culations showed correlations to experimental data. The 6-311 + G(2d,p) basis set was additionally used for better correlation in NMR studies. The first order hyperpolarizability value indicated that costunolide has nonlinear optical (NLO) properties. Costunolide stability arising from hyperconjugative interactions and charge delocalisation was analysed using natural bond orbital (NBO). Thermodynamic parameters also correlated in the temperature range 10 0-70 0 K. The molecular docking results showed that costuno-lide binds strongly to the Onchocerca volvulus main protease with a relative binding affinity of -5.94 kcal mol-1 and an inhibition constant of 44.61 mu M.(c) 2023 Elsevier B.V. All rights reserved.

This mini review describes the research between 1962 and 2019 on ethnobotany, chemistry and pharmacology of Harungana madagascariensis (Hypericaceae), the unique plant species in the genus Harungana. The plant is mainly distributed in Africa and Europe, where it has been used in the traditional medicine to cure several diseases. The first chemical investigation of H. madagascariensis genus took place earlier in 1962 with the isolation of harunganin whose the structure was characterized by X-ray. Several works have been done over the last 57 years on leaves, bark, roots and branches of the plant and as result, 42 secondary metabolites belonging to numerous classes of compounds including anthranoids, anthraquinones, xanthones, triterpenoids, flavonoids, steroids and alkaloids have been isolated and are presented herein together with some derivatives obtained from chemical transformations including thermal rearrangement and allylation. The anthranoids reported from natural sources represent almost 49 % of the total secondary metabolites obtained from the genus and display the most potent biological activities. Along with anthraquinones, they constitute the chemo markers of Harungana. The extracts and compounds from the plant have been evaluated for their potencies in antimicrobial, anti-protozoan, anti-sickling, anti-inflammatory, antioxidant, enzyme inhibition or cytotoxic activities. The results support the uses of H. madagascariensis in folk medicine and provide further evidence in new drugs discovery.

Two furanocoumarin derivatives, 3-methoxypsoralen (1) and 3,5-dimethoxypsoralen (2), along with nine known compounds, friedelinol (3), 3-oxo-11β-hydroxyoleanan-12-ene (4), lupeol (5), taraxer-3-one (6), a mixture of β-sitosterone (7a) and stigmast-4,22-dien-3-one (7b), ergosterol (8), 9,19-cyclolanost-3-one-24,25-diol (9), oleanan-12-ene-3,11-dione (10), and β-sitosterol 3-O-β-D-glucopyranoside (11) were isolated from the twigs of Ficus chlamydocarpa. Their structures were established by NMR spectroscopic analyses and HRESIMS. The structure of 1 was further confirmed from its single crystal X-ray diffraction. The crude extract, fractions and some isolated compounds were assessed for their preliminary antibacterial activity and cytotoxicity. One of the fractions (FB-B3) exhibited inhibition against the bacterial strain Pseudomonas agarici and induced a remarkable cytotoxic activity toward the human cervix carcinoma cell line KB-3-1 (IC50 0.166 mg/mL), and compounds 1, 6, and 7 showed moderate antibacterial activity against Bacillus subtilis and Micrococcus luteus.

Phytochemical investigation of the stem bark extract of Trichilia emetica led to the isolation of two new naturally occurring compounds including a prieurianin-class limonoid named trichirokin (1) and the steroid ergosta-5,24(28)-diene-3S, 16S, 20S-triol (4), along with nine known compounds characterized as rohituka-3 (3), rohituka-9 (2), scopoletin, benzoic acid, protocatechuic acid, lignoceric acid, beta-sitosterol, stigmasterol and beta-sitosterol-3-O-beta-D-glucopyranoside. The crystal structures of rohituka-3 (3) and ergosta-5,24(28)-diene-3S, 16S, 20S-triol (4) are reported here for the first time. The structures of the compounds were elucidated by extensive spectroscopic and spectrometric data interpretation. The stereochemistry of compound 1 was established on the basis of its NOESY spectrum and the comparison of its optical rotation value with that of its congener 2. None of the reported compounds displayed antibacterial or cytotoxic activity.

The phytochemical investigation of the ethyl acetate soluble fraction of Duguetia staudtii stem bark led to the isolation of eight compounds consisting into a new bisnorlignan named pachypolignan (1), a known bisnorlignan (2), four flavonoids (3–6), one alkaloid (7), and one triterpenoid (8). The structures of all the compounds were established with help of spectral data including IR, UV, MS, 1D- and 2D-NMR spectroscopic data, as well as by comparison with previously-reported data in literature. The anti-inflammatory and urease inhibitory activities of the isolated compounds were assessed. Furthermore, the chemotaxonomic significance of these compounds was discussed.

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.

Nine known com­pounds have been isolated from Combretum glutinosum leaves, including flavonoids and triterpenes. The crystal structures of umuhengerin and (20S,24R)-ocotillone are reported for the first time; the latter structure confirms the absolute configuration. The crude extracts and the isolated com­pounds were tested for their anthelmintic activity on the larvae and adult worms of Haemonchus contortus. The best activity on both stages of the parasite was obtained with the flavonoids., A chemical study of the hydro-ethanol extract of the leaves of Combretum glutinosum resulted in the isolation of nine com­pounds, including 5-de­methyl­sin­en­se­tin (1), umuhengerin (2), (20S,24R)-ocotillone (3), lupeol (4), β-sitosterol (5), oleanolic acid (6), betulinic acid (7), corymbosin (8) and β-sito­sterol glucoside (9). Four com­pounds have been isolated for the first time from the genus Combretum [viz. (1), (2), (3) and (8)]. The crystal structures of flavonoid (2), C20H20O8, Z′ = 2, and triterpene (3), C30H50O3, Z′ = 1, have been determined for the first time; the latter confirmed the absolute configuration of native (20S,24R)-ocotillone previously derived from the crystal structures of related derivatives. The mol­ecules of (3) are linked into supra­molecular chains by inter­molecular O—H⋯O hydrogen bonds. The crude extracts obtained by aqueous decoction and hydro-ethano­lic maceration, as well as the nine isolated com­pounds, were tested for their anthelmintic activity on the larvae and adult worms of Haemonchus contortus, a hematophage that causes parasitic disorders in small ruminants. The evaluated anthelmintic activity showed that the extracts at different doses, as well as all the com­pounds tested at 150 µg ml−1, inhibited the migration of the larvae and the motility of the adult worms of the parasite com­pared with the phosphate buffer solution negative reference control. The best activity was obtained with flavonoids (1), (2) and (8) on both stages of the parasite. The flavones that showed good activity can be used for the further development of other derivatives, which could increase the anthelmintic efficacy.

Phytochemical investigation of the stem bark of Ficus natalensis afforded eleven compounds including one ceramide (1), two anthraquinones (2, 3), four triterpenes (4–7), two polyols (8, 9) and two steroids (10, 11). The structures of the compounds were determined by spectroscopic analyses including IR, UV, MS, 1D- and 2D- NMR (1H, 13C, 1H–1H COSY, HMQC, HMBC and NOESY), as well as by comparison with literature data. The antibacterial activity and the cytotoxicity of the extract, fractions and some isolated compounds (3, 5, 8 and 9) were evaluated. Some fractions and sub-fractions from various column chromatography displayed moderate antibacterial activity with diameter zone of inhibition (DZI) ranging from 7 to 10 mm. None of the compounds tested had activity. In the present study, all the compounds are isolated for the first time from the species F. natalensis. Compounds 2, 4–7, 10 and 11 were previously reported from the genus Ficus. The chemophenetic significance of the isolated compounds is discussed.

The phytochemical exploration of the Entandrophragma candollei stem bark extract led to the isolation and identification of twenty compounds including three undescribed phragmalin-class limonoids named encandollens C-E (1-3), the undescribed protolimonoid 5 together with sixteen known compounds. The structures of all the isolated compounds were determined by interpretation of their spectroscopic and spectrometric data including HRMS, 1D and 2D NMR analyses. The assignment of the absolute and relative stereochemistry of the undescribed compounds was achieved using SC-XRD analyses as well as NOESY experiments. The previously reported structure of odoratone (5a) was corrected as 23R,24S-dihydroxy-22S,25-epoxytirucall-7-en-3-one (5) based on its NMR and SC-XRD data. Prieurianin (4) exhibited high cytotoxic activity on KB3-1cell lines with an IC50 of 1.47muM compared to the reference griseofulvin (IC50=17-21muM). The results of the in silico docking of compound 4 supported and delivered further insights on its cytotoxicity. Copyright © 2020 Elsevier Ltd. All rights reserved.

Senegalin (

From the ethno-medicinally used leaves of Mallotus oppositifolius, four acylphloroglucinol derivatives, namely Acronyculatin S U (1–3) and Mallotojaponin D (4) were isolated along with seven known compounds (5–11). Structures were elucidated by comprehensive spectroscopic analyses and HRMS data. Absolute configurations were assigned by careful comparison of their specific optical rotation with those of closely related compounds. Compounds 1, 2, 6 and 11 demonstrated inhibitory activity against the bacterial strains E. coli, S. aureus, S. typhi, P. aeruginosa with minimum inhibitory concentration (MIC) values ranging from 3.125 to 50 μg/ml.

Senegalin (1), a new phenylpropanoid has been isolated from the stem bark of Ekebergia senegalensis A. Juss. along with twelve known secondary metabolites including coumarins 2-5, 4-hydroxy-3,5-methylbenzoic acid (6), pentacyclic triterpenoids 7-9, acyclic triterpenoids 10 and 11 and steroids 12 and 13, respectively. Their structures were elucidated with the help of spectroscopic techniques including 1D- and 2D-NMR. The antibacterial activity of the major compounds (2, 9-11) was evaluated on five bacterial strains. However, only compounds 2 and 11 showed a weak inhibition against Bacillus subtilis and Pseudomonas agarici. Furthermore, the chemotaxonomic significance of these compounds has also been elaborated.

An extensive phytochemical study of the aerial parts of Vernonia guineensis Benth. (Asteraceae) led to the isolation of a new flavone, vernoguinoflavone (1) and a naturally isolated glycerol ester, bisarachidicester (2), together with eighteen known secondary metabolites including quercetin (3), luteolin (4), vernopicrin (5), vernomelitensin (6), beta-amyrin (7), oleanolic acid (8), ursolic acid (9), lupeol (10), betulinic acid (11), beta-carotene (12), a mixture of stigmasterol (13) and beta-sitosterol (14), beta-sitosterol-3-O-beta-D-glucoside (15), 2,3-dihydroxypropyl heptacosanoate (16), pentacosanoic acid (17), docosan-1-ol (18), tritriacontan-1-ol (19), and heptatriacontan-1-ol (20). Compounds 3, 4, 7-9, 12 and 16-20 are reported herein for the first time from this species. The structures of these compounds were elucidated based on extensive spectroscopic analyses, particularly 1D and 2D NMR, and HR-ESI-MS and by comparison of their data with those reported in the literature. The crude extract, fractions and some isolated compounds were evaluated for their antibacterial activity against Gram-negative bacteria: Escherichia coli (ATCC 25922), Shigella flexineri (NR 518), Salmonella Muenchen, Salmonella typhimurium and Salmonella typhi (ATCC 19430). All the tested compounds demonstrated inhibitory activities against the tested enteric bacteria with MIC values ranging from 3.12 to 100 g/mL. Flavonoids 1, 3 and 4 isolated from the most active fraction demonstrated the best bioactivities against Escherichia coli, Salmonella Muenchen and Salmonella typhimurium with MIC values ranging from 3.12 to 25 g/mL. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The chemical investigation of the roots of Vernonia guineensis Benth. (Asteraceae) resulted in the isolation of a new ceramide, named vernoguinamide (1), together with fifteen known compounds, including three anthraquinones, physion (2), erythroglaucin (3) and emodin (4), three triterpenoids, hop-17(21)-en-3 beta-yl acetate (5), lupeol (6) and betulinic acid (7), six steroids, vernoguinoside A (8), vernoguinoside (9), beta-sitosterol 3-O-beta-D-glucoside (10), stigmasterol 3-O-beta-D-glucoside (11), stigmasterol (12) and beta-sitosterol (13) and three fatty acid derivatives, tetracosanoic acid (14), tricosanic acid (15) and arachidic acid glycerol ester (16). The structure of the new compound as well as those of the known compounds were established by spectrometric analysis including HRESI-MS, 1D and 2D-NMR and by comparison with the previously reported data. Among these compounds, the anthraquinones 2-4 and the triterpene 5 were isolated for the first time from Vernonia genus and compounds 6, 7 and 14-16 were extracted for the first time from the species. The isolated compounds were tested for their antibacterial activity and 3, 8 and 9 were the most active compounds against the tested bacteria. Furthermore, the chemophenetic relationships of the isolated compounds and their significance were also discussed.

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.

Two xanthones, 2-(3-hydroxy-3,3-dimethyldihydroallyl)-dihydro-6-deoxyisojacareubin (1) and dihydro-6-deoxyjacareubin (2), and two 3 ⟶ 8 rotameric biflavonoids, (2R,3S)-volkensiflavone-7-O-β-acetylglucopyranoside (3) and (2S,3S)-morelloflavone-7-O-β-acetylglucopyranoside (4), together with fifteen known compounds, were isolated from a dichloromethane/methanol (1:1, v/v) extract of the bark of the plant Allanblackia floribunda. The structures of the new compounds were elucidated by NMR spectroscopy and mass spectroscopic techniques and those of the known ones were deduced by comparison with data reported in the literature. The isolated biflavonoids were obtained as mixtures of conformers exhibiting duplicate NMR signals in solution at 25 °C and their respective absolute configurations were assigned using circular dichroism spectroscopy. Selected isolated compounds were assessed for their antibacterial and antioxidant properties.

Objectives For centuries, the genus Entandrophragma (Meliaceae), endemic to Africa, has been used in traditional medicine for the treatment of several illnesses. This review deals with large range of phytochemicals from the genus Entandrophragma and their pharmacological potentials covering the period from 1967 to 2018. Key findings Phytochemical investigations of the genus Entandrophragma led to the report of about 166 secondary metabolites which have been thoroughly summarized herein including some of their semisynthetic derivatives obtained from chemical transformations as well as their biological activities in the medicinal and agricultural domains. The limonoids or meliacins and their precursor called protolimonoids (protomeliacins) reported so far represent almost 69.28% of the total secondary metabolites obtained from the genus, and they display the most potent biological activities. Collectively, both classes of metabolites constitute the markers of Entandrophragma. However, squalene-type triterpenoids and sesquiterpenoids were reported only from the species E. cylindricum and therefore could be its chemotaxonomic markers. Summary The pharmacological investigations of the extracts of some species exhibited interesting results which support the traditional uses of these Entandrophragma plants in folk medicine. Some compounds revealed promising antiplasmodial and anti-inflammatory activities and deserve therefore further attention for new drug discovery.

Two alchornoic acid derivatives, deepoxyalchornoic acid ( 1 ) and bisalchornoicester ( 2 ), together with six known compounds, alchornoic acid ( 3 ), gallic acid, 4- O -methylgallic acid, shikimic acid, kaempferol-3- O -galactoside and 2,3-dihydroxypropyl octacosanoate were isolated from a dichloromethane/methanol-soluble extract of the ripe fruits of the Cameroonian medicinal plant Alchornea cordifolia . The structures of the new fatty acid derivatives were elucidated by interpretation of their HRESIMS, 1D and 2D NMR spectroscopic data and by comparison with those reported in the literature. Some of the isolated compounds demonstrated inhibition activity against the microbial strains Escherichia coli, Klebsiella pneumoniae and Citrobacter braakii .

Pseudarthria hookeri is used in Africa for the treatment of pneumonia, cough, abdominal pains and diarrhea. However the bioactive constituents underlying the health benefits associated with P. hookeri remain unknown. In this study, the antibacterial activity and the cytotoxicity of compounds isolated from Pseudarthria hookeri were investigated. The antibacterial activity was assessed by determining the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) using the broth microdilution method and the antiproliferative effect against cancer cells was determined by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay. Compounds 1 and 4 showed the highest antibacterial effect with minimum inhibitory concentration (MIC) values ranging from 16 to 32 and 8 to 64 μg/mL, against Gram-positive and Gram negative bacteria, respectively. The same compounds induced a remarkable cytotoxic activity toward human T-Cell leukemia Jurkat cells with respective IC50 values of 3.59 and 5.59 μg/mL. Our results suggest that flavonoids from P. hookeri exhibit significant antibacterial activity and antiproliferative effect on human cancer cell lines. These compounds might underlie the health benefits associated with the plant. Compounds 1 and 4 emerged as promising drug candidates, highlighting their potential as lead compounds.

Chemical investigation of the roots of Entandrophragma congoënse (Meliaceae) led to the isolation of two new 3,4-seco-tirucallane triterpenes, namely seco-tiaminic acids B and C (1 and 2) together with nine known compounds: 3,4-secotirucalla-21-formyl-23-oxo-4(28),7,24-trien-3-oic acid (3), methyl angolensate (4), molucensin N (5), molucensin O (6), piscidinol A (7), 7α,20(S)-dihydroxy-4,24(28)-ergostadien-3-one (8), 24-methylene-cholest-5-en-3β,7α-diol (9), entilin A (10), and entilin B (11). Their structures were determined using extensive spectroscopic methods including 1D and 2D NMR, HRMS, and CD analyses; new results were compared to existing data in the literature. The two newly identified seco-tiaminic acids showed moderate antiplasmodial and cytotoxic activities against a chloroquine-sensitive strain of the malaria parasite (Plasmodium falciparum NF54) and were cytotoxic toward an L6 rat skeletal myoblast cell line, respectively.

The chemical investigation of the whole plant of Indigofera spicata Forsk (Fabaceae), a medicinal plant from Cameroon, resulted in the isolation of a new benzofuran, named spibenzofuran (1a), together with ten known secondary metabolites including one benzofuran (2), one flavonoid (3), one saponin (6), two triterpenes (4 and 5), two steroids (8 and 11), one phthalate (7) and two fatty acids (9 and 10). All these compounds have been isolated for the first time from this plant. The structures of the isolated compounds were established by spectroscopic analysis including HR-ESI-MS, 1D and 2D NMR and by comparison of our data with the reported data. The isolated compounds might be considered as the chemophenetic markers of this species, and antibacterial and urease inhibitory activities of some isolated compounds were assessed.

Combretum glutinosum and Mitragyna inermis are two plants used in Benin as a dewormer and antibiotic in traditional human and veterinary medicine. This study aimed to evaluate the anthelmintic, antimicrobial and antioxidant activities of the both plants tannin extracts. The extracts were tested in vitro on Haemonchus contortus larvae and worms and on the growth of 11 reference strains by agar medium diffusion method. Their chemical compositions were determined by UPLC-DAD-ESI-MS. It was found that total tannins extracted from plant leaves showed a strong inhibition on H. contortus larvae and adult worms compared to the negative control. Concerning the antimicrobial activity, M. inermis extract had an effect only on Pseudomonas aeruginosa with a MIC of 2.5 mg/mL. C. glutinosum extract inhibited the growth of most microbial strains with MIC values ranging from 1.25 to 20 mg/mL. The DPPH test showed that the extracts of C. glutinosum (IC50 = 8.04 µg/mL) and M. inermis (IC50 = 11.21 µg/mL) have good antioxidant activity and these results are confirmed by the FRAP method. Four (4) compounds could be identified in the tannin extract of C. glutinosum and could explain its activities. The results obtained from this work revealed that the tannins extracted from C. glutinosum showed better anthelmintic, antimicrobial and antioxidant activities compared to the extracts from M. inermis.

Three new flavonoids viz., pseudarflavones A ( 1 ) and B ( 2 ) and 6,7-(2⿳,2⿳-dimethylchromano)flavanone ( 3 ), were isolated from Pseudarthria hookeri together with thirteen known compounds: boeravinone L ( 5 ), gancaonin P ( 4 ), dorsamin F ( 10 ), emodin ( 6 ), 6-prenylpinocembrin ( 7 ), hiravanone ( 11 ), dorsmanin I ( 12 ), 6,8-diprenyleriodictyol ( 13 ), 6-prenyl-3⿲-methoxyeriodictyol ( 14 ), oblonginol ( 15 ), orobol ( 16 ), protocatechuic acid ( 17 ) and α-terthienyl ( 18 ). Their structures were elucidated by IR, MS, 1D and 2D NMR spectroscopic techniques and by comparison with data reported in the literature. Chemical transformations were also employed to confirm some assignments. The insulin secretory activity of compounds ( 1 , 3 ⿿ 18 ) was evaluated on isolated mice islets. Compounds ( 1 , 3 , 5 and 12 ) showed a mild effect on glucose stimulated insulin secretion while compounds ( 4, 10, 14 and 16 ) were found to display moderate insulin secretory activities of 247.5%, 404.8%, 350.7% and 291.8% respectively, in comparison to the control. The tested compounds showed no toxic effect on MIN-6 and 3T3 cell lines up-to 400 μM. These results demonstrated that compounds ( 10 ) and ( 14 ) showed a potential to be considered as new insulin secretagogues and that further development of their derivatives may increase their insulinotropic potential.

Two new tetracyclic polyketides with a spirocenter, simplicilones A (1) and B (2) were isolated from the broth-culture of the endophytic fungus Simplicilliumsubtropicum (SPC3) in the course of our screening for new bioactive secondary metabolites. This endophytoic fungus is naturally harboured in the fresh bark of the Cameroonian medicinal plant Duguetia staudtii (Engl. and Diels) Chatrou. The planar structures of the simplicilones were elucidated by MS and 1D as well as 2D NMR spectroscopic techniques. The relative configuration was assigned by NOESY experiments in conjunction with coupling constants, subsequently, the absolute configurations were assigned by the modified Mosher&rsquo, s method. The compounds showed weak cytotoxic effects against the cell line KB3.1 (in vitro cytotoxicity (IC50) = 25 &micro, g/mL for 1, 29 &micro, g/mL for 2), but were inactive against the tested Gram-positive and Gram-negative bacteria as well as fungi.

Two new ergostane-type steroids named tiamenones A and B (1-2) were isolated from the bark of Entandrophragma angolense (Meliaceae) along with ten known compounds identified as 20S-hydroxy-4,6,24(28)-ergostatrien-3-one (3), 3beta,7alpha,20beta-trihydroxyergosta-5,24(28)-diene (4), 3beta,5alpha-dihydroxyergosta-7,22-diene (5), stigmasterol, beta-sitosterol, beta-amyrin, oleanolic acid, asperphenamate, sucrose and daucosterol. The structures of the isolated compounds have been established using NMR spectroscopic and mass spectrometric analyses. The assignment of relative and absolute configurations of compound 1 was achieved by a NOESY experiment and comparison of its NMR data with those of known compound reported in literature. Compounds 1-3, beta-amyrin and asperphenamate were evaluated for their antibacterial potencies against five bacterial model strains viz. Escherichia coli DSMZ 1058, Pseudomonas agarici DSMZ 11810, Bacillus subtilis DSMZ 704, Micrococcus luteus DMSZ 1605 and Staphylococcus warneri DSMZ 20036 and their cytotoxicity on two cell lines KB3-1 and HT-29. No potencies were exhibited by the tested compounds even at the highest concentration of 0.5 mg/mL. Compounds 1-3 were found to be potential HIV-1 inhibitors based on their molecular docking analyses. Copyright © 2020. Published by Elsevier Inc.

A new dimeric naphtho-γ-pyrone, 2-hydroxydihydronigerone (1), along with five compounds, nigerone (2), pyrophen (3), kojic acid (4), 4-(hydroxymethyl)-5-hydroxy-2H-pyran-2-one (5), and p-hydroxyphenylacetic acid (6), was isolated from an endophytic fungus Aspergillus niger AKRN associated with the roots of Entandrophragma congoënse. The structure of the new compound has been elucidated using spectroscopic data including 1D and 2D NMR as well as the high-resolution mass spectrometry. Compounds 1–5 showed weak antimicrobial activity on five selected Gram-negative bacteria, namely Enterobacter aerogenes (CM64), Enterobacter cloacae (BM67), Klebsiella pneumonia (K2), and Escherichia coli (ATCC8739 and ATCC10536).

Two new tirucallane-type triterpenoids were isolated from the bark of Entandrophragma congoënse (Meliaceae) along with five known compounds gladoral A, bipendensin, 4-hydroxymethyl-3,5-dimethyldihydrofuran-2(3H)-one, scopoletin and 5,7-dimethoxy-6-hydroxycoumarin. Their structures were elucidated by means of spectroscopic analyses including 1D and 2D-NMR spectroscopy, high resolution mass spectrometric data as well as the comparison of data with those reported in the literature. The tested compounds (1-4) displayed moderated antiplasmodial activity against erythrocytic stages of chloroquine-resistant Plasmodium falciparum strain NF54 and low cytotoxicity on L6 cell lines. All the isolated compounds are reported for the first time from the genus Entandrophragma.

Phytochemical investigation of the endophytic fungus Microdiplodia sp. afforded a new m-anisaldehyde derivative named microdiplanol (1) and a new 24-methylcholestanol derivative named microdiplane (2). Their structures were confirmed by a comprehensive analysis of 1D and 2D NMR and mass spectrometric data.

One of the major problems with the formulation of herbal medicines is the quality control of plant material to ensure its efficacy and safety. Quality control of medicinal plants requires analysis of many bioactive compounds present in the plant. C-alkylated flavonoids are an important bioactive subclass of flavonoids. A simple, rapid, sensitive and selective method is presented here for the quantification of bioactive C-alkylated flavonoids. This is the first quantitative method for analysis of C-alkylated flavonoids based on the multiple reaction monitoring (MRM) approach so far. This study focuses on method development for quantification of bioactive C-alkylated flavonoids. Quantification of a total of five C-alkylated flavonoids was done employing the MRM approach on an HPLC-QqQ-MS instrument. LODs and LOQs for quantified flavonoids were in the range of 0.41–1.32 and 1.23–3.96 ng/mL, respectively. Linear calibration curves between 25 and 1500 ng/mL were obtained with the regression coefficients of ≥0.996. Accuracy (% bias) and precision (% RSD) of the analyses were found to be less than 5%. Developed HPLC-ESI-MS/MS can be employed as a quality control method of plant raw materials.

A new spiroalkaloid, 7-epi-javaniside (1), was isolated from the Cameroonian plant Pauridiantha callicarpoides, along with seven known compounds viz., javaniside (2), sweroside (3), hymexelsin (4), scopoletin (5), 7,7`-dihydroxy-6,6`-dimethoxy-8,8`-biscoumarin (6), 7,7`-dihydroxy-6,6`- dimethoxy-3,3`-biscoumarin (7), and 4-hydroxy-3-methoxybenzoic acid (8). The structures of the new alkaloid, as well as those of the known compounds, were elucidated by detailed spectroscopic analysis including 1D and 2D NMR and by comparison with the literature data for related compounds.

Four acyclic triterpene derivatives named sapelenins G–J ( 1 – 4 ), along with eight known compounds, sapelenins A–D, ekeberin D2 ( 5 ), (+)-catechin and epicatechin, and anderolide G, were isolated from the stem bark of the Cameroonian medicinal plant, Entandrophragma cylindricum Sprague, on the basis of bioassay-guided fractionation. Their structures were determined by means of high-resolution mass spectrometry and NMR spectroscopic data, as well as by comparison with the literature values of their analogs. The absolute configurations of the compounds ( 1 – 4 ) were assigned by the modified Mosher’s method in conjunction with NOESY experiments and chemical modifications. The anti-inflammatory activities of the sapelenins were evaluated by assessing their ability to suppress or inhibit the secretion of cytokine interleukin-17 (IL-17) by human peripheral blood mononuclear cells (PBMC) stimulated with phytohemagglutinin (PHA). The cytotoxicity of these compounds on PMBCs was further assessed for correctly interpreting their anti-inflammatory responses. The tested compounds demonstrated moderate to significant anti-inflammatory activities by suppressing the secretion of IL-17 by PHA-stimulated human PBMCs. One of them, sapelenin G ( 1 ), showed high potency in suppressing the secretion of IL-17 by PBMCs comparable to reference cyclosporine A, without causing any cytotoxic effects (negligible), and deserves further considerations towards developing an effective anti-inflammatory drug.

Two prenylated anthranoids, psorantin and kenganthranol E, were isolated from the fruit of Psorospermum aurantiacum together with the known compounds ferruginin B, vismin, vismion D, haronginanthrone, kenganthranol B, kenganthraquinone, 1,7-dihydroxyxanthone, paradisiol, fridelin, fridelinol and betulinic acid. Their structures were determined on the basis of spectral data and by comparison with data reported in the literature as well as with authentic specimens for the known compounds. The structures of the new compounds were determined as bis-[3,8,9-trihydroxy-6-methyl-4,4-bis-(3,3-dimethylallyl)anthracenyl]methane ( 1 ) and 1,8,10-trihydroxy-6-methyl-4,5-bis-(3,3-dimethylallyl)-2,3-(2,2-dimethylpyrano)anthrone ( 2 ). Psorantin ( 1 ) is a dimer of vismin formed through a methylene linkage. The two new compounds when tested against the microbial strains Bacillus megaterium , Escherichia coli , Chlorella fusca and Microbotryum violaceum showed no activity.

From the extracts of all parts of the plant Helichrysum cameroonense, five compounds were isolated and identified. One of them, a ceramide, named cameroonemide A (1), is reported for the first time as a new natural product. Its structure was determined by comprehensive analyses of their 1D and 2D NMR and HR-EI-MS spectral data. The remaining four known compounds were identified by comparing their spectroscopic data with those reported in the literature as kaurenoic acid (2), 3-acetyloxykaurenoic acid (3), beta-sitosterol (4), and beta-sitosterol glucopyranoside (5). Preliminary studies showed that 3-acetyloxykaurenoic acid (3) inhibited the alga Chlorella fusca, while kaurenoic acid (2) showed strong antibacterial activity against Bacillus megaterium.

Four new iridoids viz., plumeridoids A, B, and C and epiplumeridoid C were isolated from the stem bark of Plumeria rubra Linn. together with twenty-four known compounds viz., 1-( P-hydroxyphenyl)propan-1-one, isoplumericin, plumericin, dihydroplumericin, allamcin, fulvoplumerin, allamandin, plumieride, P- E-coumaric acid, 2,6-dimethoxy- P-benzoquinone, scopoletin, cycloart-25-en-3 beta,24-diol, 2,4,6-trimethoxyaniline, ajunolic acid, ursolic acid, oleanolic acid, beta-amyrin acetate, betulinic acid, lupeol and its acetate, 2,3-dihydroxypropyl octacosanoate, glucoside of beta-sitosterol, and a mixture of common sterols (stigmasterol and beta-sitosterol). Their structures were determined by means of spectroscopic data including HREIMS, 1H NMR, 13C NMR, 2D NMR (HMQC, HMBC, NOESY) and by comparison with published data. All but one of thirteen tested compounds exhibited antifungal, antialgal, and/or antibacterial activities.

Four natural nitro metabolites, 1-hydroxy-5-methoxy-2-nitronaphthalene (2), 1,5-dimethoxy-4-nitronaphthalene (3), 1-hydroxy-5-methoxy-2,4-dinitronaphthalene (4), and 1,5-dimethoxy-4,8-dinitronaphthalene (5), known from chemical synthesis but new as natural products, were isolated together with two known compounds, 1-hydroxy-5-methoxynaphthalene (1) and ergosterol (6) from an endophytic fungus, Coniothyrium sp. The structures of 1–6 were determined by spectroscopic methods including 1D and 2D NMR experiments and by mass spectrometric measurements. The structures of 1–4 were confirmed by chemical synthesis. The nitronaphthols showed considerable antibacterial, antifungal, and antialgal properties.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)