AUTHOR=Otogo N’nang Elvis , Essone Paulin N. , Ella Ndong Judicael , Boueya Augustin , Kokou Kossiwa , Kriz Richard , N’nengué Marie Andrée , Ovono Abessolo Félix , Lell Bertrand , Kremsner Peter G. , Agnandji Selidji T. 

TITLE=LC-MS based analysis reveal antimicrobial compounds from Gabonese pharmacopoeia: chemical characterisation and cytotoxicity evaluation

JOURNAL=Frontiers in Natural Products

VOLUME=3

YEAR=2025

URL=https://www.frontiersin.org/journals/natural-products/articles/10.3389/fntpr.2024.1478361

DOI=10.3389/fntpr.2024.1478361

ISSN=2813-2602

ABSTRACT=<p>Plants used in traditional medicine represent an important source of new compounds. <italic>Hallea ledermannii</italic> (<italic>H</italic>. <italic>ledermannii</italic>) (Krause) Verdc. (Rubiaceae), Gossypium <italic>barbadense</italic> (G. barbadense) (Malvaceae), Pycnanthus <italic>angolensis</italic> (<italic>P</italic>. <italic>angolensis)</italic> (Myristicaceae), <italic>Drypetes gossweileri</italic> (<italic>D</italic>. <italic>gossweileri</italic>) S. Moore (Euphorbiaceae) and <italic>Scyphocephalium ochocoa</italic> (<italic>S</italic>. <italic>ochocoa</italic>) Warb (Myristicaceae) are five plants widely used in traditional Gabonese medicine as antimicrobials. However, little is known about the active compounds associated with their biological activities. Based on botanical studies and the claims of traditional healers regarding the antimicrobial effects of these plants, a study to evaluate the antimicrobial activity and phyto-chemical profile of aqueous extracts of three plants (bark of <italic>H</italic>. <italic>ledermannii</italic>, <italic>G</italic>. <italic>barbadense</italic> root bark and <italic>P</italic>. <italic>angolensis</italic> bark) and methanolic extracts of two plants (<italic>S</italic>. <italic>ochocoa</italic> stem bark and <italic>D</italic>. <italic>gossweileri</italic> root bark). Under the guidance of LC-MS detection, identified twenty seven (<bold>27</bold>) potentially active compounds. Eight (<bold>8</bold>) of these belong to the quinovic acid-type triterpenoid sap-onins identified in the aqueous extract of <italic>H</italic>. <italic>ledermannii</italic>, eleven (<bold>11</bold>) are dibenzofurans, chroman and stigmasterol detected in the methanolic extract of <italic>S</italic>. <italic>ochocoa</italic> and eight (<bold>8</bold>) compounds in the methanolic extract of <italic>D</italic>. <italic>gossweileri</italic> are friedelin, drypemolundein B and gossweilone, to name but a few. In parallel, the five extracts were tested on reference bacterial strains: <italic>Staphylococcus aureus</italic> ATCC 25923, <italic>Pseudomonas aeruginosa</italic> ATCC 278533, <italic>Salmonella thyphi</italic> ATCC 13311, <italic>Klebsiella pneumoniae</italic> ATCC 700603, <italic>Shigella flexneri</italic> ATCC 24570. Three of these extracts (aqueous extract of <italic>H</italic>. <italic>ledermannii</italic> and two methanolic extracts of <italic>S</italic>. <italic>ochocoa</italic> stem bark and <italic>D</italic>. <italic>gossweileri</italic> root bark) showed moderate activity against <italic>Staphylococcus aureus</italic> ATCC 25923, with inhibition zones of 12.3 ± 0.5 mm, 10.1 ± 0.5 mm and 7,6 ± 0 mm respectively. In addition, we assessed the toxicity of the three extracts that showed antimicrobial activity using an invertebrate model, <italic>Galleria mellonella</italic> (<italic>GM</italic>). We found that the LD varied according to the concentration of the plant material. The aqueous extract of <italic>H</italic>. <italic>ledermannii</italic> and the methanolic extracts of <italic>S</italic>. <italic>ochocoa</italic> and <italic>D</italic>. <italic>gossweileri</italic> were not toxic to <italic>G. mellonella</italic>. The LD<sub>50s</sub> (mg/mL) obtained were 93.2 mg/mL [717.2 g/kg body weight (bw)] and 100 mg/mL (762.3 g/kg bw), 95.4 mg/mL [721.1 g/kg body weight (bw)].</p>