A NEW SOURCE OF KOJIC ACID ISOLATED FROM KIGELIA AFRICANA: A POSSIBLE PRECURSOR FOR QUINONE BIOSYNTHESIS

ABSTRACT Kojic acid (5-hydroxy-2-hydroxymethyl-γ-pyrone) a fungal metabolite produced by Aspergillus spp., Penicillium spp. and belonging mainly to the flavus-oryzaetamarii groups was isolated for the first time from Kigelia africana as the major constituent by mass fragmentation guided isolation. From a biosynthetic consideration, Kojic acid is a possible intermediate in the synthesis of the quinone scaffolds

Antimicrobial activities of the methanol extract, fractions and compounds from <it>Ficus polita </it>Vahl. (Moraceae)

Abstract Background Many plants of the family Moraceae are used in the treatment of infectious diseases. Ficus polita Vahl., an edible plant belonging to this family is used traditionally in case of dyspepsia, infectious diseases, abdominal pains and diarrhea. The present work was designed to assess the antimicrobial activity of the methanol extract from the roots of F. polita (FPR), as well as that of its fractions (FPR1-5) and two of the eight isolated compounds, namely euphol-3-O-cinnamate (1) and (E)-3,5,4'-trihydroxy-stilbene-3,5-O-β-D-diglucopyranoside (8). Methods The liquid microdilution assay was used in the determination of the minimal inhibitory concentration (MIC) and the minimal microbicidal concentration (MMC), against seven bacterial and one fungal species. Results The results of the MIC determination showed that the crude extract, fractions FPR1, FPR2 and compound 8 were able to prevent the growth of the eight tested microorganisms. Other samples showed selective activity. The lowest MIC value of 64 μg/ml for the crude extract was recorded on 50% of the studied microbial species. The corresponding value for fractions of 32 μg/ml was obtained on Salmonella typhi, Escherichia coli and Candida albicans ATCC strains. The MIC values recorded with compound 8 on the resistant Pseudomonas aeruginosa PA01 strain was equal to that of chloramphenicol used as reference antibiotic. Conclusion The obtained results highlighted the interesting antimicrobial potency of F. polita as well as that of compound 8, and provided scientific basis for the traditional use of this taxon in the treatment of microbial infections.</p

(−)-Brunneusine, a new phenolic compound with antibacterial properties in aqueous medium from the leaves of Agelanthus brunneus (Engl.) Tiegh (LORANTHACEAE)

Agelanthus brunneus (Loranthaceae) is a hemiparasitic plant growing on Senna siamea (Fabaceae). The chemical investigation of its leaves and flowers led to the isolation of one new phenolic compound namely (-)-brunneusine (1), together with 13 known compounds. The crude leaves and flowers extracts (CLE and CFLE) with their ethyl acetate fractions (EAFL and EAFFL) and some isolated compounds (1-3; 8-9 and 11-14) have been tested on four bacterial species of sanitary importance isolated in an aquatic environment. All the samples except compound 3 showed antibacterial activity with MICs ranging from 0.43 to 8.88.103 μg/mL and MBCs from 0.43 to 3.55.103 μg/mL. Compounds 9 and 14 showed better activity on all bacterial species tested with MICs ranging from 0.43 to 27.77 μg/mL. Only CLE, EAFL and compounds 14, 2, 8 and 9 showed bactericidal effects on all bacterial species tested

Chemical constituents of two Cameroonian medicinal plants: Sida rhombifolia L. and Sida acuta Burm. f. (Malvaceae) and their antiplasmodial activity

Kamdoum BC, Simo I, Wouamba SCN, et al. Chemical constituents of two Cameroonian medicinal plants: Sida rhombifolia L. and Sida acuta Burm. f. (Malvaceae) and their antiplasmodial activity. Natural product research. 2021.An extensive phytochemical investigation of the EtOH/H2O (7:3) extracts of Sida rhombifolia L. and Sida acuta Burm. f., yielded a previously undescribed ceramide named rhombifoliamide (1) and a xylitol dimer (2), naturally isolated here for the first time, as well as the thirteen known compounds viz, oleanolic acid (3), beta-amyrin glucoside (4), ursolic acid (5), beta-sitosterol glucoside (6), tiliroside (7), 1,6-dihydroxyxanthone (8), a mixture of stigmasterol (9) and beta-sitosterol (10), cryptolepine (11), 20-Hydroxyecdysone (12), (E)-suberenol (13), thamnosmonin (14) and xanthyletin (15). Their structures were elucidated by the analyses of their spectroscopic and spectrometric data (1D and 2D NMR, and HRESI-MS) and by comparison with the previously reported data. The crude extracts, fractions, and some isolated compounds were tested against chloroquine-sensitive (3D7) and chloroquine-resistant (Dd2) Plasmodium falciparum strains. All the tested samples demonstrated moderate and/or significant activities against 3D7 (IC50 values: 0.18-20.11g/mL) and Dd2 (IC50 values: 0.74-63.09g/mL)