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

Antibacterial constituents of Rumex nepalensis spreng and its emodin derivatives

Nguengang RT, Tchegnitegni BT, Ateba JET, et al. Antibacterial constituents of Rumex nepalensis spreng and its emodin derivatives. Natural Product Research. 2022.The CH2Cl2-MeOH (1:1) extract of roots of Rumex nepalensis (Polygonaceae) displayed significant antibacterial activity against five bacterial strains with MICs (62.5-31.2mug.mL-1). The EtOAc soluble fraction displayed a significant activity against the same strains with MICs (31.2-3.9mug.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 1.9mug.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 15.6mug.mL-1, respectively)

Bioactive Arylnaphthalide Lignans from Justicia depauperata

Tchegnitegni Toussie B, Nguengang Tchuinkeu R, Mawabo IK, et al. Bioactive Arylnaphthalide Lignans from Justicia depauperata . Journal of Natural Products. 2022

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

Nguengang RT, Tchegnitegni BT, Nono ECN, et al. Constituents of the Stem Bark of Symphonia globulifera Linn. f. with Antileishmanial and Antibacterial Activities. Molecules. 2023;28(6): 2473.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

Chemical constituents from Baphia leptobotrys Harms (Fabaceae) and their chemophenetic significance

Wonkam AKN, Ngansop CAN, Tchuenmogne MAT, et al. Chemical constituents from Baphia leptobotrys Harms (Fabaceae) and their chemophenetic significance. Biochemical Systematics and Ecology. 2021;96: 104260.The chemical investigation of the CH2Cl2/MeOH (1:1) extract of the trunk bark and leaves of Baphia leptobotrys Harms (Fabaceae) led to the isolation of nineteen compounds (1-19). Their structures were elucidated based on the analysis of their NMR and MS data. Except for compounds 3-5, 14 and 15, all the isolated compounds are reported from the genus Baphia for the first time. Furthermore, compounds 8, 10, 16, 17 are isolated from the Fabaceae family for the first time. The crude extract and isolated compounds were screened in vitro for their antileishmanial activity against Leishmania donovani 1S (MHOM/SD/62/1S) promastigotes and cytotoxicity towards Raw 264.7 macrophage cells. The crude extract of B. leptobotrys exhibited moderate activity (IC50 = 63.40 mu g/mL). Amongst the tested compounds, ergosterol peroxide (9) and germanicol caffeoyl ester (8) exhibited good activity with IC50 values of 9.43 and 10.24 mu M, respectively and showed acceptable selectivity towards macrophage cells (SI > 3.85). The chemophenetic significance of these compounds is also discussed

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

Nono HW, Donfack Nanfack AR, Tchegnitegni BT, et al. Foetidumins A-D, and other chemical constituents from Helichrysum foetidum (L.) Moench (Asteraceae) with antiparasite activity. Phytochemistry. 2023;210: 113672.The phytochemical investigation of the MeOH and CH2Cl2-MeOH (1:1) extracts from the flowers and twigs of Helichrysum foetidum (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 muM, 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 mug/mL, respectively. Copyright © 2023. Published by Elsevier Ltd

New lignan glycosides from Justicia secunda Vahl (Acanthaceae) with antimicrobial and antiparasitic properties

Three new lignan glucosides, namely, justisecundosides A (1), B (2a), and C (2b), were isolated from the whole plant of Justicia secunda together with seven known compounds (3−9). Their structures were established based on a comprehensive analysis of HR-ESI-MS, IR, UV, and CD, in conjunction with their 1D and 2D-NMR data. A putative biogenetic pathway of compounds 1−2a,b from coniferyl alcohol was proposed. In addition, the antimicrobialactivities of the extract, fractions, and some isolated compounds were assessed against multiresistant bacterial and fungal strains. Furthermore, the antiplasmodial, antileishmanial, and antitrypanosomal activities were assessed against the sensitive (3D7) and multidrug-resistant (Dd2) strains of P. falciparum, promastigote and bloodstream forms of L. donovani, and Trypanosoma brucei, respectively. Compound 4 exhibited moderate antibacterial activity against Staphylococcus aureus SA RN 46003 with a MIC value of 62.5 μg/mL. Besides, compound 6 demonstrated a very good activity against sensitive (IC50 Pf3D7: 0.81 μg/mL) and multidrug-resistant (IC50 PfDd2: 14.61 μg/mL) strains of P. falciparum while compound 4 displayed good antitrypanosomal activity (IC50: 1.19 μg/mL). Also, compound 1 was the most active on the promastigote form of L. donovani with an IC50 of 13.02 μg/mL

In Vitro Assessment of the Cercaricidal Activity of Sida acuta Burm. F. and Sida rhombifolia Linn. (Malvaceae) Hydroethanolic Extracts, Cytotoxicity, and Phytochemical Studies

Membe Femoe U, Kadji Fassi JB, Boukeng Jatsa H, et al. In Vitro Assessment of the Cercaricidal Activity of Sida acuta Burm. F. and Sida rhombifolia Linn. (Malvaceae) Hydroethanolic Extracts, Cytotoxicity, and Phytochemical Studies. Evidence-based Complementary and Alternative Medicine. 2022;2022: 7281144.Despite the global efforts, schistosomiasis remains a public health problem in several tropical and subtropical countries. One of the major challenges in the fight against schistosomiasis is the interruption of the parasite life cycle. Here, we evaluated the anticercarial, cytotoxicity, and phytochemical profiles of Sida acuta (HESa) and Sida rhombifolia (HESr) hydroethanolic extracts (Malvaceae). Schistosoma mansoni cercaria was collected from fifteen Biomphalaria pfeifferi-infected snails. Twenty-five cercariae were incubated in duplicate with different concentrations (31.25-1,000mug/mL) of HESa or HESr. The cercaria viability was monitored at 30min time intervals for 150min, and the concentration-response curve of each plant extract was used to determine their respective lethal concentration 50 (LC50). Additionally, the cytotoxicity profile of each plant extract was evaluated on the Hepa 1-6cell line at a concentration range of 15.625-1,000g/mL using the WST-8 assay method and its inhibitory concentration 50 (IC50) was calculated. Moreover, phytochemical characterization of each plant extract was carried out by HPLC-MS. Both extracts exhibited cercaricidal activity in a time- and concentration-dependent manner. At 30min time point, HESa (LC50=28.41±3.5g/mL) was more effective than HESr (LC50=172.42±26.16g/mL) in killing S. mansoni cercariae. Regarding the cytotoxicity effect of both extracts, the IC50 of HESa (IC50=109.67g/mL) was lower than that of HESr (IC50=888.79g/mL). The selectivity index was 3.86 and 5.15 for HESa and HESr, respectively. Fifteen compounds were identified from HESa and HESr after HPLC-MS analysis. N-Feruloyltyramine, a polyphenol, and thamnosmonin, a coumarin, were identified in both extracts. HESa and HESr displayed cercaricidal activity and were not toxic on Hepa 1-6 cell line. Based on the selectivity index of these extracts, S. rhombifolia extract could be more effective on S. mansoni cercariae than S. acuta extract. This study could provide baseline information for further investigations aiming to develop plant-based alternative drugs against S. mansoni. Copyright © 2022 Ulrich Membe Femoe et al

Antimicrobial and Cytotoxic Activities of Constituents from the Fruit of Albizia lebbeck L. Benth (Fabaceae)

Leutcha BP, Dzoyem JP, Jouda J-B, et al. Antimicrobial and Cytotoxic Activities of Constituents from the Fruit of Albizia lebbeck L. Benth (Fabaceae). Molecules. 2022;27(15): 4823.Twenty-two compounds were isolated from the fruit of Albizia lebbeck including one unprecedented, rare amino acid-derived zwitterionic and one new flavone derivative. The isolation was performed on repeated column chromatography over silica gel and their structures were determined by 1D-, 2D-NMR and HR-ESI-MS spectra together with reported data in the literature. The chemophenetic significance is also discussed. Some isolated compounds were reported for the first time to be found in the species. Additionally, compound 2 showed antibacterial activity and compounds 1 and 2 revealed moderate cytotoxic activity against the Raw 264.7 cancer cell line with IC50 values of 37.19 µM and 29.36 µM, respectively. Furthermore, a proposed biosynthetic pathway of compound 1 is described

Chemical constituents of Mussaenda erythrophylla Schumach. & Thonn. (Rubiaceae) and their chemophenetic significance

Bouzeko ILT, Dongmo FLM, Ndontsa BL, et al. Chemical constituents of Mussaenda erythrophylla Schumach. & Thonn. (Rubiaceae) and their chemophenetic significance. Biochemical Systematics and Ecology. 2021;98: 104329.The chemical investigation of the CH2Cl2/MeOH (1:1) extract from the aerial part of Mussaenda erythrophylla Schumach. & Thonn. (Rubiaceae) resulted in the isolation of sixteen known compounds (1-16) distributed in coumarins, flavonoid glucosides, quinic acid derivatives, triterpenoids, monoglycerid, steroids, tetraterpenoid and polyol. The structures of the compounds were determined by spectrometric and spectroscopic analysis including MS and NMR data followed by their comparison with reported ones in the literature. The chemophenetic significance of the isolated compounds was discussed. The crude extract and some of the isolated compounds were assessed in vitro for their antileishmanial, cytotoxic and antiplasmodial activities. The crude extract of M. erythrophylla showed moderate antileishmanial activity (IC50 = 61.6 mu g/mL) while the hexane soluble fraction showed good antileishmanial activity (IC50 = 31.06 mu g/mL) compared to the reference drug amphotericin B (IC50 = 0.11 mu M). Compounds 11 and 9 also exhibited potent antileishmanial activity (IC50 = 53.7-52.0 mu M). The crude extract as well as the ethyl acetate soluble fraction also exhibited good antiplasmodial activity (IC50 = 7.43 +/- 0.00 mu g/mL and 14.49 +/- 2.96 mu g/mL respectively), while compounds 11, 15 and 16 showed weak activity with IC50 > 20 mu M compared to the reference drug artemisinin (IC50 = 0.014 +/- 0.001 mu M)