Cytotoxicity of epunctanone and four other phytochemicals isolated from the medicinal plants Garcinia epunctata and Ptycholobium contortum towards multi-factorial drug resistant cancer cells.

INTRODUCTION: Resistance of cancer cells is a serious impediment to chemotherapy and several phytochemicals are active against multi-drug resistant (MDR) phenotypes. The cytotoxicity of five naturally occurring compounds: betulin (1), mundulea lactone (2), seputhecarpan A (3), seputheisoflavone (4) and epunctanone (5) was evaluated on a panel of 9 cancer cell lines including various sensitive and drug-resistant cell lines. The modes of action of compound 5 were further investigated. METHODS: The resazurin reduction assay was used to evaluate cytotoxicity of samples and ferroptotic cell death induced by compound 5; caspase-Glo assay was used to detect the activation of caspases in CCRF-CEM leukemia cells treated with compound 5. Flow cytometry was used for cell cycle analysis in CCRF-CEM cells treated with compound 5, as well as detection of apoptotic cells by annexin V/PI staining, analysis of mitochondrial membrane potential (MMP) and measurement of reactive oxygen species (ROS). RESULTS: Compounds 1-5 displayed cytotoxic effects in the 9 studied cancer cell lines with IC50 values below 70 µM. The IC50 values varied from 8.20 µM (in HCT116 (p53-/-) colon cancer cells) to 35.10 µM (against HepG2 hepatocarcinoma cells) for 1, from 8.84 µM (in CEM/ADR5000 leukemia cells) to 48.99 µM (in MDA-MB-231 breast adenocarcinoma cells) for 2, from 12.17 µM (in CEM/ADR5000 cells) to 65.08 µM (in MDA-MB-231 cells) for 3, from 23.80 µM (in U87MG.ΔEGFR glioblastoma cells) to 68.66 µM (in HCT116 (p53-/-) cells) for 4, from 4.84 µM (in HCT116 (p53-/-) cells) to 13.12 µM (in HepG2 cells) for 5 and from 0.02 µM (against CCRF-CEM cells) to 122.96 µM (in CEM/ADR5000 cells) for doxorubicin. Compound 5 induced apoptosis in CCRF-CEM cells through alteration of MMP and increase in ROS production. In addition to apoptosis, ferroptosis was also identified as another mode of cell death induced by epunctanone. CONCLUSIONS: Compounds 1-5 are valuable cytotoxic compounds that could be used to combat MDR cancer cells. Benzophenoe 5 is the most active molecule and deserve more investigations to develop new anticancer drugs.

Cytotoxicity of seputhecarpan D, thonningiol and 12 other phytochemicals from African flora towards human carcinoma cells.

BACKGROUND: Despite the remarkable progress in cancer therapy in recent years, this disease still remains a serious public health concern. The use of natural products has been and continues to be one of the most effective ways to fight malignancies. The cytotoxicity of 14 compounds from African medicinal plants was evaluated in four human carcinoma cell lines and normal fibroblasts. The tested samples included: ß-spinasterol (1), friedelanone (2), 16ß-hydroxylupeol (3), ß-amyrin acetate (4), lupeol acetate (5), sequoyitol (6), rhamnitrin (7), europetin 3-O-rhamnoside (8), thonningiol (9), glyasperin F (10), seputhecarpan B (11), seputhecarpan C (12), seputhecarpan D (13) and rheediaxanthone A (14). METHODS: The neutral red uptake (NR) assay was used to evaluate the cytotoxicity of samples; caspase-Glo assay, flow cytometry for cell cycle analysis and mitochondrial membrane potential (MMP) as well as spectrophotometry to measure levels of reactive oxygen species (ROS) were performed to detect the mode of action of compounds 9 and 13 in MCF-7 breast adenocarcinoma cells. RESULTS: Compounds 3, 9-13 displayed cytotoxic effects against the four tested cancer cell lines with IC50 values below 85 µM. Compounds 9 and 13 had IC50 values below 10 µM in 4/4 and 3/4 tested cell lines respectively. The IC50 values varied from 0.36 µM (against MCF7 cells) to 5.65 µM (towards colon carcinoma DLD-1 cells) for 9, from 9.78 µM (against MCF7 cells) to 67.68 µM (against HepG2 cells) for 13 and 0.18 µM (towards HepG2 cells) to 72 µM (towards Caco-2 cells) for the reference drug, doxorubicin. Compounds 9 and 13 induced cell cycle arrest in Go/G1 whilst doxorubicin induced arrest in G2/M. The two molecules (9 and 13) also induced apoptosis in MCF-7 cells through activation of caspases 3/7 and 9 as well as enhanced ROS production. CONCLUSION: Compounds 9 and 13 are good cytotoxic phytochemicals that should be explored more in future to develop a cytotoxic drug to fight human carcinoma.

A new fatty aldol ester from the aerial part of Mimosa invisa (Mimosaceae).

A new aldol ester named 17-O-triacontanoylheptadecanal (1) was isolated from the aerial part of Mimosa invisa (Mimosaceae) together with eight known compounds identified as ß-sitosterol (2), α-amyrine (3), lupeol (4), 4'-O-methylepinumisoflavone (5), alpinumisoflavone (6), betulinic acid (7), 3-O-ß-D-glucopyranoside of sitosterol (8) and epirobinetinidol (9). The structures of compounds were determined on the basis of NMR and mass spectrometry data as well as by comparing the data reported in the literatures. The antimicrobial activities of the crude extract and compounds 1 and 9 were investigated against seven microbial species. The natural products showed moderate activities compared to that of the crude extract.

Antimicrobial activity of the crude extract, fractions and compounds from stem bark of Ficus ovata (Moraceae).

AIM OF THE STUDY: This study was designed to investigate the antimicrobial activities of the methanol extracts from the stem bark of Ficus ovata (FOB), fractions (FOB1-6) and compounds isolated following bio-guided fractionation [3-friedelanone (1), taraxeryl acetate (2), betulinic acid (3), oleanoïc acid (4), 2-hydroxyisoprunetin (5), 6,7-(2-isopropenyl furo)-5,2,4-trihydroxyisoflavone (6), Cajanin (7) and protocatechuic acid (8)]. MATERIALS AND METHODS: The micro-dilution method was used for the determination of the minimal inhibition concentration (MIC) and the minimal microbicidal concentration (MMC) against fungi (two species), gram-positive (three species) and gram-negative bacteria (five species). RESULTS: The results of the MIC determinations indicated that the crude extract (FOB), fractions FOB2 and FOB4 as well as compound 5 were active on the entire studied organisms. Other samples showed selective activity, fractions FOB1, FOB3 and FOB5 being active against 50% of the tested microbial species while FOB6 was active on 40%. Compounds 8, 6, 2 and 7 prevented the growth of 80%, 70%, 50% and 20% of the organisms respectively. The lowest MIC value (156 g/ml) observed with the crude extract was recorded on Streptococcus faecalis, Candida albicans and Microsporum audouinii. The corresponding value for fractions (39 microg/ml) was noted with FOB4 against Staphylococcus aureus, while that of the tested compounds (10 microg/ml) was observed with compound 8 on Microsporum audouinii. The results of the MMC determination suggested that the cidal effect of most of the tested samples on the studied microorganisms could be expected. CONCLUSIONS: The overall results provided evidence that the studied plant extract, as well as some of the isolated compounds might be potential sources of new antimicrobial drug.

Diterpenoids from the stem bark of Croton zambesicus.

Three clerodane diterpenoids, crotozambefurans A, B and C were isolated from the stem bark of Croton zambesicus together with the known clerodane crotocorylifuran and two trachylobanes: 7 beta-acetoxytrachyloban-18-oic acid and trachyloban-7 beta, 18-diol. Betulinol, lupeol, sitosterol and its 3 beta-glucopyranosyl derivative were also obtained. The structures of crotozambefurans A, B and C were determined, respectively, as: 15,16-epoxy-1,3,13(16),14-clerodatetraen-20,12-olide-18,19-dioic acid dimethylester, 15,16-epoxy-1,3,13(16),14-clerodatetraen-18,19,20-trioic acid trimethylester and 15,16-epoxy-3,13(16),14-clerodatrien-19,1 alpha:20,12-diolide-18-oic acid methylester, using spectroscopic analysis, especially, NMR spectra in conjunction with 2D experiments, COSY, HSQC, HMBC and TOCSY.