Cytotoxic Compounds from the Leaves of Garcinia polyantha

Lannang AM, Tatsimo SJN, Fouotsa H, Dzoyem JP, Saxena AK, Sewald N. Cytotoxic Compounds from the Leaves of Garcinia polyantha. Chemistry & Biodiversity. 2014;11(6):975-981.A new compound, named banganxanthone C (=12-(1,1-dimethylprop-2-en-1-yl)-5,10-dihydroxy-9-methoxy-2-methyl-2-(4-methylpent-3-en-1-yl)-2H, 6H-pyrano[3,2-b]xanthen-6-one; 4), together with five known compounds, were isolated from the leaves of Garcinia polyantha. The structures of the compounds were elucidated on the basis of 1D- and 2D-NMR spectroscopy. Among the known compounds, two were xanthones, one was a pentacyclic triterpene, one sterol, and one benzophenone derivative. Isoxanthochymol (2) and 4-[(2E)-3,7-dimethylocta-2,6-dien-1-yl]-1,5,8-trihydroxy-3-methoxy-9H-xanthen-9-one (3) exhibited significant antiproliferative activity against the leukemia cell line TPH-1 with IC50 inhibition values of 1.5 and 2.8 mu g/ml, respectively. The cytotoxic activity was found to be related to apoptosis induction

A new xanthone derivative from twigs of Garcinia nobilis

Fouotsa H, Tatsimo SJN, Neumann B, et al. A new xanthone derivative from twigs of Garcinia nobilis. Natural Product Research. 2014;28(14):1030-1036.Phytochemical investigation of the twigs of Garcinia nobilis led to the isolation of a new xanthone, named l-hydroxy-2,5-dimethoxyxanthone (1), together with 15 known compounds (2-16). The structures of the new and known compounds were established by means of spectroscopic methods and by comparison with previously reported data. The structure of compound 1 was confirmed by X-ray diffraction data. Compounds 1-16 were tested for their cytotoxic activity against human cervix carcinoma cell line KB-3-1. Compounds 5 and 11 showed moderate activity while others showed weak biological activity in these cytotoxicity assays. Compounds 4 and 9 were found to be inactive

Antibacterial and antioxidant activities of isolated compounds from Prosopis africana leaves

Yanda L, Tatsimo SJN, Tamokou J-D-D, et al. Antibacterial and antioxidant activities of isolated compounds from Prosopis africana leaves. International Journal of Analytical Chemistry . 2022;2022: 4205823.Prosopis africana (G. &Perr.) Taub (Mimosaceae) is a large tree native to dry tropical Africa and characteristic of dry leguminous forests. Different parts of this plant are used to treat wounds, skin infection, and to fight against cancer. Literature review indicated various pharmacological properties. Despite these medicinal properties, the chemical composition studies remain limited. This study aims to isolate and characterize secondary metabolites from P. africana leaves and evaluate their antibacterial and antioxidant properties. Air-dried powdered leaves of P. africana were macerated in methanol at room temperature and partitioned with ethyl acetate. The EtOAc extract was subjected successively to flash and column chromatographies in order to isolate compounds. The structure of the isolates was determined with help of spectroscopic data including 1D and 2D NMR experiments and comparison with literature data. The antibacterial activities were evaluated via determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The antioxidant activities were evaluated via gallic acid equivalent antioxidant capacity (GEAC) and diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays. The chemical investigation of the EtOAc extract led to the isolation of seven compounds: (2E, 6E) farnesylamine (1), myricetin-3-O-rhamnoside (2), bis(2-ethylhexyl) benzene-1,2-dicarboxylate (3), lupeol (4), SS-sitosterol (5), stigmasterol glycoside (6), and a mixture of bis(2-ethylhexyl) benzene-1,2-dicarboxylate (3) and bis(2-ethylhexyl) benzene-1,4-dicarboxylate (7) in ratio 1:2. Compound 1 is described here for the first time as a natural product with complete 1H and 13C assignments. Compounds 3 and 7 were identified as artefacts from dichloromethane. Sesquiterpene amine (1) is reported in Prosopis genus for the first time. Antibacterial and antioxidant activities of isolated compounds were investigated. Among the tested samples, the EtOAc extract and compound 2 exhibited the highest antioxidant (EC50=5.67-77.56mug/mL; GEAC=36.58-89.28mug/mL) and antibacterial (MIC=8-64mug/mL) activities against gram-negative and gram-positive bacteria. The EtOAc extract and compound 2 from P. africana exhibited antibacterial activity through bacteriolytic effects and reduction of the antioxidant defenses in the bacterial cells. Furthermore, the chemotaxonomic significance of isolated compounds was discussed. The antibacterial and antioxidant activities of ethyl acetate extract and compound 2 can justify the traditional uses of P. africana leaves for the treatment of diseases related to bacterial infections. The presence of compounds 1, 2, and 4 in this plant should also be considered as valuable chemotaxonomic features. Copyright © 2022 Lambert Yanda et al

Antibacterial and Antioxidant Xanthones and Benzophenone from Garcinia smeathmannii

Fouotsa H, Lannang AM, Dzoyem JP, et al. Antibacterial and Antioxidant Xanthones and Benzophenone from Garcinia smeathmannii. Planta Medica. 2015;81(7):594-599.A new prenylated xanthone, 1,3,5,8-tetrahydroxy-2-(3-methybut-2-enyl)-4-(3,7-dimethylocta-2,6-dienyl) xanthone (1), and a new benzophenone (2), together with four known xanthone derivatives, cheffouxanthone (3), smeathxanthone A (4), smeathxanthone B (5), ananixanthone (6), and two pentacyclic triterpenes, epi-friedelinol (7) and friedelin (8), were isolated from the stem bark of Garcinia smeathmannii. The structures of the compounds were elucidated on the basis of 1D and 2DNMR experiments, and compound 2 was further characterized and confirmed by single X-ray analysis. Compounds 1, 2, and 3 exhibited the most prominent antibacterial activity against gram-positive Enterococcus faecalis with minimal inhibitory concentration values of 8, 8, and 2 mu g/mL, respectively, while compounds 1, 3, 4, and 6 showed the capacity to scavenge free radicals

A new depsidone derivative from the leaves of Garcinia polyantha

Lannang AM, Sema DK, Tatsimo SJN, et al. A new depsidone derivative from the leaves of Garcinia polyantha. Natural product research. 2018;32(9):1033-1038.One new depsidone, polyanthadepsidone A (1), together with four known compounds were isolated from the dichloromethane extract of the leaves of Garcinia polyantha. The structures of all compounds were determined by comprehensive analyses of their 1D and 2D NMR and EI mass spectral data. All the isolates exhibited suppressive effect on phagocytosis response upon activation with serum opsonised zymosan in the IC50 range of 4.5-23.80M, tested in vitro for oxidative burst studies of whole blood. [GRAPHICS]

New indane and naphthalene derivatives from the rhizomes of Kniphofia reflexa Hutchinson ex Codd

Sema DK, Lannang AM, Tatsimo SJN, et al. New indane and naphthalene derivatives from the rhizomes of Kniphofia reflexa Hutchinson ex Codd. Phytochemistry Letters. 2018;26:78-82.Two new (1-2) and eight known (3-10) secondary metabolites were isolated from the rhizomes of Kniphofia reflexa Hutchinson ex Codd. Among them, an indane derivative kniphofiarindane (1), and naphthalene derivative kniphofiarexine (2), were identified as new natural products. 1D- and 2D-NMR spectroscopic studies together with single-crystal X-ray diffraction techniques were employed in the structural elucidation of the new compounds, 1 and 2. These compounds were evaluated for their cytotoxic effect against kidney epithelial cell line (LLC-MK2). Compound 3 was found to be highly cytotoxic, while compounds 1, and 10 showed moderate cytotoxicity with CC50 values of 4.44 +/- 0.79, 16.35 +/- 1.54, and 11.24 +/- 1.22 mu g/mL, respectively against the tested standard Gleevec (Imatinib), (CC (50) = 18.50 +/- 1.21 mu g/mL). Compounds 8, and 9 also showed moderate anti-inflammatory activity (CC (50 )= 38.7 +/- 4.90, and 20.00 +/- 4.40 mu g/mL, respectively) against ROS production