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Phoenix sylvestris Roxb. (Arecaceae) seeds are used in the treatment of diabetes in the traditional system of medicine. The present study evaluated antihyperglycemic and antioxidant activities as well as the total phenolic and flavonoid content of the methanol extract of P. sylvestris seeds (MEPS). The constituents of the extract were identified by GC–MS analysis. MEPS demonstrated strong antioxidant activity against 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) (IC50 = 162.70 ± 14.99 μg) and nitric oxide (NO) (IC50 = 101.56 ± 9.46 μg/ml) free radicals. It also possesses a substantial amount of phenolics and flavonoids. It significantly (p <.05) reduced blood glucose levels in glucose‐loaded and alloxan‐induced diabetic mice at the doses of 150 and 300 mg/kg b.w., respectively. A total of 46 compounds were detected and identified by gas chromatography–mass spectroscopy (GC–MS) analysis, among which 8‐methylisoquinoline N‐oxide (32.82%) was predominant. The phytochemical study by GC–MS revealed that the MEPS possesses compounds which could be related to its antidiabetic and antioxidant activities. To recapitulate, P. sylvestris seeds can be a very good option for antidiabetic and antioxidant activity though further studies are still recommended to figure out the responsible phytochemicals and establish their exact mechanism of action. [ABSTRACT FROM AUTHOR]

New clerodane diterpenes, 12-epi-megalocarpodolide D (2) and an epimeric mixture of crotonolins A (3) and B (4), were isolated from the bark of Croton oligandrus following a bioassay-guided isolation protocol. Known compounds, megalocarpodolide D (1), 12-epi-crotocorylifuran (5), cluytyl-ferulate (6), hexacosanoyl- ferulate (7), vanillin (8), acetyl-aleuritolic acid (9) and lupeol (10), were also isolated. The structures of the isolated compounds (1–10) were elucidated by spectroscopic means. The cytotoxicity of compounds 1–10 was assessed against A549, MCF7, PC3 and PNT2 cell lines using the MTT assay. Compounds 1 and 2 showed moderate levels of activity against both A549 and MCF7 cells with 1 being the most active with IC50 values of 63.8 ± 13.8 and 136.2 ± 22.7 µM against A549 and MCF7 cells, respectively. The epimeric mixture of 3 and 4 was moderately active against A549 and PC3 cells (IC50 = 128.6 ± 31.0 and 111.2 ± 2.9 µM, respectively). [ABSTRACT FROM AUTHOR]

The bioassay-guided fractionation of the n-hexane extract of Citrus reticulata Blanco (Rutaceae) stem bark yielded scoparone (1), xanthyletin (2), lupeol (3), β-amyrin (4), stigmasterol (5), β-sitosterol (6) and palmitic acid. The structures of these compounds were determined by comprehensive spectroscopic analyses, i.e., 1D and 2D NMR and EI-MS, and by comparison with the reported data. Extracts, fractions and isolated compounds 1-6 were assessed for cytotoxicity by the 3-(4,5-dimethylthiazol-2-yl)-2,5-dphenyltetrazolium bromide (MTT) assay against three human cancer cell lines, i.e., human lung adenocarcinoma cell line A549, human breast adenocarcinoma cell line MCF7 and human Caucasian prostate adenocarcinoma cell line PC3. Significant activity of the n-hexane and the dichloromethane extracts was observed against the breast cancer cell line MCF7 with IC50 s of 45.6 and 54.7 μg/mL, respectively. Moreover, the 70% ethyl acetate in n-hexane chromatographic fraction showed significant activity displaying IC50 values of 53.0, 52.4 and 49.1 μg/mL against the cancer cell lines A549, MCF7 and PC3, respectively. Encouragingly, an IC50 of 510.0 μg/mL against the human normal prostate cell line PNT2 indicated very low toxicity and hence favourable selectivity indices for the 70% ethyl acetate in n-hexane fraction in the range of 9.6-10.4 towards cell lines A549, MCF7 and PC3. Because compounds isolated from the above fraction only delivered IC50 values in the range of 18.2-96.3, 9.2-34.1 and 7.5-97.2 μg/mL against A549, MCF7 and PC3 cell lines, respectively, synergistic action between compounds is suggested. Bioassay results valorize the anticancer effectivity of the stem bark of this plant in Cameroonian pharmacopoeia. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]