Cytotoxicity of a new tirucallane derivative isolated from Stereospermum acuminatissimum K. Schum stem bark.

Leutcha BP, Sema DK, Dzoyem JP, et al. Cytotoxicity of a new tirucallane derivative isolated from Stereospermum acuminatissimum K. Schum stem bark. Natural product research. 2020:1-6.One new tirucallan derivative, leutcharic acid (1) was isolated from Stereospermum acuminatissimum stem bark together with the known compounds 3-oxo-22-hydroxyhopane (2), 3,4-secotirucalla-4(28),7,24-trien-3,21-dioic acid (3), 3-oxotirucalla-7,24-dien-21-oic acid (7), lupeol (4), beta-sitosterol (5) and stigmasterol (6). The structures of the isolated compounds were elucidated using 1D and 2D NMR spectroscopy in combination with literature data. To the best of our knowledge, this is the first report on the cytotoxic properties' constituents of S. acuminatissimum. Cytotoxicity of compounds 1 and 2 was assessed invitro with the WST-1 assay on human lung adenocarcinoma A549 and THP-1 human monocytic leukaemia cell lines. Both compounds showed antiproliferative activity on the cancer cells. Compound 2 was more active against THP-1 with an IC50 value of 26.83M. The sensitivity of THP-1 cells to compounds 1 and 2 indicated that these compounds might be potential leads for anticancer agent development against leukaemia

In Vitro and in Vivo Evaluation of the Antimalarial Activities of Kniphofia reflexa Hutchinson ex Codd

Sema DK, Lannang AM, Zofou D, et al. In Vitro and in Vivo Evaluation of the Antimalarial Activities of Kniphofia reflexa Hutchinson ex Codd. Natural Product Communications. 2022;17(10): 1934578X221133582.In a phytochemical investigation of the rhizomes of Kniphofia reflexa, an endemic plant used to treat relapsing fevers in Kejom, northwestern Cameroon, 12 known (1-12) compounds were obtained following chromatographic methods and purification, together with 3 new derivatives (13-15) prepared by acetylation. One-dimensional and 2-dimensional nuclear magnetic resonance spectroscopic studies together with infrared and ultraviolet spectral analyses in association with data found in the literature were used to determine the structure of the compounds. In the in vitro evaluation of compounds 1-9, 12-14, and the crude extract against Plasmodium falciparum chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains, cassiamin C (1) [IC50 0.57 +/- 0.54 (D6); 0.78 +/- 0.08 (W2)], and crude extract [IC50 1.06 +/- 0.22 (D6); 1.08 +/- 0.12 (W2)] were highly active against the parasites. Kniphofiarexine (12) was inactive. However, its derivative, kniphofiarexine B (14), was moderately active. In the in vivo studies, the extract suppressed Plasmodium berghei growth, but did not clear completely the parasites

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

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]

A New Chromene Derivative and a New Polyalcohol Isolated From the Fungus Xylaria sp. 111A Associated With Garcinia polyantha Leaves

Tegha HF, Jouda J-B, Dzoyem JP, et al. A New Chromene Derivative and a New Polyalcohol Isolated From the Fungus Xylaria sp. 111A Associated With Garcinia polyantha Leaves. Natural Product Communications. 2021;16(1).From the crude extract of the plant-associated fungus Xylaria sp. collected in Cameroon, a new 2H-chromene derivative, hexacycloxylariolone (1), and a new polyalcohol, xylatriol (2), were isolated, in addition to 3 known compounds, 2,3-furandiol (3), 1,8-dimethoxynaphthalene (4), and 1-palmitoyl-rac-glycerol (5). Their chemical structures were established on the basis of the interpretation of spectroscopic data. Hexacycloxylariolone (1), 1,8-dimethoxynaphthalene (4), and 1-palmitoyl-rac-glycerol (5) showed antiproliferative activity by inhibiting the growth of Raw 264.7 and THP-1 cancer cell lines

A New Unsaturated Aliphatic Anhydride from Aspergillus candidus T(12)19W1, an Endophytic Fungus, from Pittosporum mannii Hook f.

Juidzou GT, Anoumedem EGM, Sema DK, et al. A New Unsaturated Aliphatic Anhydride from Aspergillus candidus T(12)19W1, an Endophytic Fungus, from Pittosporum mannii Hook f. Journal of Chemistry. 2023;2023: 5938723.A new unsaturated aliphatic anhydride derivative (Z)-(12Z)-heptadec-12-enoic-2 '-hydroxypropanoic anhydride (1) and ten known compounds, three flavonoids (2-4), two terphenyllins (5-6), four triterpenoids (7-8, 10-11), and one n-fatty acid (9), were isolated from the EtOAc extract of Aspergillus candidus T(12)19W1, an endophytic fungus, inhabiting Pittosporum mannii. All the isolated compounds were characterized using 1D- and 2D-NMR and HR-EI experiments together with the reported literature. p-terphenyls are suggested to be the chemophenetic marker of the genus Aspergillus. The ethyl acetate crude extract as well as some isolated compounds of A. candidus was assayed for antibiofilm activity, anti-inflammatory (ROS) activity, and cytotoxicity on brine shrimps and the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cytotoxicity assay on 3T3 cell lines. The tested sample showed good antibiofilm activity with the lowest MBEC50 obtained at 64 mu g/mL. Compounds showed low anti-inflammatory activity even at high concentration (250 mu g center dot mL(-1) with an IC50 of 59.6 +/- 0.1 mu g center dot mL(-1)) with moderate cytotoxicity on brine shrimps at high concentration (1000 mu g center dot mL(-1), with 46.67% mortality). However, no cytotoxic activity was observed against 3T3 cell lines

Heptacyclosordarianone, a New Polyketide From Sordaria sp., an Endophytic Fungus From Garcinia polyantha

Tankeu VFT, Sema DK, Jouda J-B, et al. Heptacyclosordarianone, a New Polyketide From Sordaria sp., an Endophytic Fungus From Garcinia polyantha. Natural Product Communications. 2020;15(11): 1934578X20977622.One new polyketide derivative, heptacyclosordarianone (1), together with 2 known compounds, heptacyclosordariolone (2) and sordariol (3), were isolated from an extract of Sordaria sp. AM-71, an endophytic fungus inhabiting Garcinia polyantha. The structures of these compounds were elucidated based on intensive nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry and by comparison with literature data. All compounds were assayed for their antimicrobial and cytotoxic properties. Only compound 2 showed antimicrobial activities against Bacillus subtilis DSMZ 704, Pseudomonas agarici DSMZ 11810, and Micrococcus luteus DSMZ 1605 with minimum inhibitory concentration values of 9.3, 15.5, and 16.9 mu g/mL respectively. None of the isolated compounds showed a significant cytotoxic property

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