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Since the emergency of coronavirus disease 2019, no specific drug has been developed within the fighting program against its spread. In Cameroon, it has been reported that the dish “yellow soup” can significantly curb the progress of the disease, while no chemical investigations have been done so far to support that conclusion. Chemical investigations of four selected spices of that dish led to the isolation of a total of 44 distinct pure compounds, which were identified using spectroscopic data. Furthermore, the docking scores of the isolated compounds were inspected by AutoDock4.2.6 software toward SARS-CoV-2 multi-targets involving main protease (Mpro), helicase, papain-like protease (PLpro), and human angiotensin‐converting enzyme 2 (ACE2). The most potent isolated compounds underwent molecular dynamics (MD) simulations over 100 ns. Stigmasterol demonstrated outstanding potency toward Mpro and PLpro with ΔG binding values of −35.6 and −36.6 kcal/mol, respectively, compared to nirmatrelvir. Nevertheless, 3β-taraxeryl acetate revealed good binding affinity against helicase and lupeol unveiled superior binding energy toward ACE2 compared to nirmatrelvir. Post-MD analyses manifested great steadiness of the isolated compounds within the binding pockets of SARS-CoV-2 targets throughout 100 ns MD simulations. Stigmasterol, 3β-taraxeryl acetate, and lupeol are recommended for further in vivo/in vitro tests toward SARS-CoV-2 multi-targets.

The liana Urera gravenreuthii Engl. is an endemic plant to Cameroon which was not yet been chemically and pharmacologically investigated so far despite its uses for medical purposes in local folk medicine to treat several illnesses including dysentery, neuralgia and malaria. This study mainly aimed to contribute to providing further information on the chemical composition of the plant and to identify its antiplasmodial compounds which might support its effectiveness against malaria. The purification of the methanolic extract of U. gravenreuthii led to the isolation and characterization of fifteen distinct compounds (1 ‒ 15) which were structurally confirmed using their NMR data. Thirteen compounds (1 ‒ 11, 14 ‒ 15) were evaluated for their antiplasmodial activity against P. falciparum 3D7 and the results showed that the most active were betulinic acid (2) (2.2 ± 0.2 μ M), rutin (9) (2.8 ± 1.4 μ M), quercetin (8) (3.7 ± 1.3 μ M) and lupeol (1) (4.8 ± 0.3 μ M) which displayed a good activity with IC 50 < 5 μ M. Furthermore, the hypotheses on the structure-activity relationship of the tested compounds and the chemotaxonomic significance of the study have been discussed. The results support the identification of the plant as a member of the family Urticaceae, strengthen its use for the management of malaria and qualify it as an important source of good candidates in new antiplasmodial drug development. [Display omitted] • This is the first chemical and biological investigation of Urera gravenreuthii. • Fifteen compounds have been isolated from the methanolic extract. • Betulinic acid (2) and rutin (9) were the most active with IC 50 values of (2.2 ± 0.2 μM) and (2.8 ± 1.4 μM), respectively, against P. falciparum 3D7. • The structure-activity relationship of the isolated compounds has been discussed. • The obtained results classifies the plant as an important source of antiplasmodial leads for new drugs discovery. [ABSTRACT FROM AUTHOR]

In Cameroon, malaria is still the cause of several deaths yearly and leading to the continued search for new potent leads to fight against Plasmodium falciparum. Medicinal plants like Hypericum lanceolatum Lam. are introduced in local preparations for the treatment of affected people. The bioassay-guided fractionation of the crude extract of the twigs and stem bark of H. lanceolatum Lam. led to the identification of the dichloromethane-soluble fraction as the most active (with 32.6% of the parasite P. falciparum 3D7 survival) which was further purified by successive column chromatography to obtain four compounds identified by their spectrometric data as two xanthones 1,6-dihydroxyxanthone (1) and norathyriol (2) and two triterpenes betulinic acid (3) and ursolic acid (4). In the antiplasmodial assay against P. falciparum 3D7, the triterpenoids 3 and 4 displayed the most significant potencies with IC50 values of 2.8 ± 0.8 μg/mL and 11.8 ± 3.2 μg/mL, respectively. Furthermore, both compounds were also the most cytotoxic against P388 cell lines with IC50 values of 6.8 ± 2.2 μg/mL and 2.5 ± 0.6 μg/mL, respectively. Further insights on the inhibition method of the bioactive compounds and their drug-likeness were obtained from their molecular docking and ADMET studies. The results obtained help in identifying additional antiplasmodial agents from H. lanceolatum and support its use in folk medicine for the treatment of malaria. The plant might be considered as a promising source of new antiplasmodial candidates in new drug discovery. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Tetrapleura tetraptera is a well-known plant widely used in Cameroon as spices in cooking and in preparations prescribed in folk medicine for the treatment of malaria. The main purpose of this study was to provide relevant chemical and pharmacological insights that can support the effectiveness of T. tetraptera against malaria by identifying the lead compounds that may be responsible for its therapeutic potential. The stem bark and root methanolic crude extracts of this plant displayed a good inhibition of P. falciparum 3D7 with rates of 83.6% and 76.3%, respectively. A total of sixteen distinct compounds (1 ‒ 16) have been isolated during the chemical investigations of the two active crude extracts. Their structures were established with the aid of their NMR data. Thriteen compounds (2 ‒ 9, 11 ‒ 13, 15 and 16) were screened for antiplasmodial activity using P. falciparum 3D7. Results showed that seven tested compounds displayed good activity (IC 50 < 7 μ M) and the most effective were compounds 5, 9, 7, 2 and 6 with IC 50 values of (1.8 ± 0.4 μ M), (1.9 ± 0.8 μ M), (2.1 ± 0.5 μ M), (2.3 ± 0.7 μ M), (2.4 ± 0.6 μ M), respectively. The in silico evaluation of the isolated compounds for their ability to inhibit the P. falciparum dihydroorotate dehydrogenase 5TBO and their ADMET studies revealed that up to fifteen isolated compounds displayed a greater affinity to the binding site of the 5TBO receptor compared to the reference drug chloroquine. More especially, compounds 1, 2, 4, 8 and 14 demonstrated a good drug-likeness. These findings support the use of T. tetraptera for the management of malaria and further qualify it as an important source of good candidates in new antiplasmodial drug development. [Display omitted] • Bioguided fractionation of the active extracts of Tetrapleura tetraptera led to isolation of sixteen compounds. • The crude extracts and thirteen compounds have been evaluated for their antiplasmodial activity against Plasmodium falciparum 3D7 strain. • Six compounds displayed good antiplasmodial activity with IC 50 ranging from 1.9 μ M to 4.4 μ M. • The action mechanism of the more potent compounds, their molecular docking and ADMET study are presented. • The obtained results further support the use of T. tetraptera for the cure of malaria in traditional medicine. [ABSTRACT FROM AUTHOR]

Stem barks of Boswellia dalzielii are used traditionally for the treatment of various bacterial infections. A bioassay guided fractionation of the MeOH-CH2Cl2 (1/1, v/v) stem barks extract led to the isolation of fourteen compounds 1–14, identified based on spectroscopic data. Dalzienoside (1) is reported here for the first time. The broth microdilution method was used to evaluate the antibacterial activity of the crude extract, fractions and compounds against six bacterial strains. The crude extract exhibited moderate antibacterial activity with MIC of 250 μL/ml; two fractions showed significant activities with MICs ranging from 7.8 to 125 μg/ml, while α-boswellic acid (2), β-boswellic acid (3), acetyl-11-keto-β-boswellic acid (4) from these fractions exhibited strong activities with MIC value of 3.125 µg/mL against Staphylococcus aureus, Salmonella typhi, Enterobacter cloacae, Streptococcus pneumonia and Pseudomonia aeruginosa. This study gives insight into the antibacterial constituents of the stem bark of B. dalzielii and justifies its use in ethnomedicine. [ABSTRACT FROM AUTHOR]

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 ), 7 α ,20( S )-dihydroxy-4,24(28)-ergostadien-3-one ( 8 ), 24-methylene-cholest-5-en-3 β ,7 α -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. [ABSTRACT FROM AUTHOR]

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(3 H )-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. [ABSTRACT FROM AUTHOR]

• Two new steroids tiamenones A and B were obtained from Entandrophragma angolense. • For the first time a steroid with a 20,24-epoxy-24-hydroxymethyl moiety was isolated. • We reported the molecular docking studies of tiamenones A, B and 20S-hydroxy-4,6,24(28)-ergostatrien-3-one to enzyme pyruvate kinase PKM2. 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 20 S -hydroxy-4,6,24(28)-ergostatrien-3-one (3), 3 β ,7 α ,20 β -trihydroxyergosta-5,24(28)-diene (4), 3 β ,5 α -dihydroxyergosta-7,22-diene (5), stigmasterol, β -sitosterol, β -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 , β -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. [ABSTRACT FROM AUTHOR]

To the best of our knowledge, this is the first chemical study of Guarea glomerulata that led to the isolation and characterisation of nine distinct compounds from its methanolic leaves extract including one new trinortriterpenoid glomerulatin along with eight known compounds amongst which five compounds namely azadirone, oleanolic acid, sericoside, cleomiscosin D and griffonin reported for the first time from the genus Guarea . All the isolated compounds have been evaluated in vitro for their antiplasmodial potency against the chloroquine-sensitive strain P. falciparum 3D7. The results showed that glomerulatin and azadirone were the most active compounds with IC 50 values of 1.02 ± 0.2  μ M and 1.48 ± 0.4  μ M, respectively. This study enriches the chemistry of the genus Guarea and further supports the identification of Meliaceae plants as a good source of antiplasmodial candidates for the development of new potent drugs against malaria.

Chemical investigations of a methanolic extract of the twigs of Vernonia amygdalina Delile (Asteraceae) resulted in the isolation and identification of three previously undescribed highly oxygenated Δ 7,9(11) stigmastane-type steroids namely vernonins U-W (1-3) along with six known compounds (4-9). The structural characterization of all the isolated compounds has been conducted via comprehensive 1D and 2D-NMR spectroscopy as well as HRMS. The seven steroidal derivatives 1-7 were evaluated for their antiplasmodial activity against the chloroquine-resistant strain P. falciparum Dd2 (PfDd2) and their hemolytic effect on human red blood cells (RBCs). Vernonins U (1), A (4) and stigmasterol-3-O-β-d-glucopyranoside (7) showed the highest activity with IC 50 values of (5.47 ± 0.01) μg/mL, (6.02 ± 0.13) μg/mL and (6.34 ± 0.80) μg/mL, respectively, against PfDd2, while vernonin W (3) showed moderate activity of (21.20 ± 0.40) μg/mL. None of the tested compounds displayed hemolytic effects on human RBCs up to 100 μg/mL indicating their safety. These results enrich the known chemistry of V. amygdalina and support its use in folk medicine for the treatment of malaria. This encourages further research towards new antiplasmodial drug candidates from this plant., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Eight new triterpenoids, prototiamins A-G (1-6, 9) and seco-tiaminic acid A (10), were isolated along with four known compounds from the bark of Entandrophragma congoënse. Their structures were elucidated by means of HRMS and different NMR techniques and chemical transformations. Assignments of relative and absolute configurations for the new compounds were achieved using NOESY experiments and by chemical modification including the advanced Mosher's method. Additionally, the structure and relative configuration of compound 3 were confirmed by single-crystal X-ray diffraction analysis. Compounds 1, 3, and 5 displayed significant in vitro antiplasmodial activity against the erythrocytic stages of chloroquine-sensitive Plasmodium falciparum strain NF54. Prototiamin C (3) was the most potent of the compounds isolated, with an IC50 value of 0.44 μM. All compounds tested showed low cytotoxicity for the L6 rat skeletal myoblast cell line.