Stigmalactam from Orophea enterocarpa induces human cancer cell apoptosis via a mitochondrial pathway

Two new triterpenoids with antimicrobial activity from the leaves and twigs of Orophea yunnanensis

Two new triterpenoids, 3-O-(4',5'-dihydroxybenzoyl)-lup-20(29)-en (1) and 3-O-(6'-desmethysyringyl)-13α-methyl-27-norolean-14-en-3β-ol (2), were isolated from the leaves and twigs of Orophea yunnanensis. Their structures were identified by extensive spectroscopic experiments (NMR and MS) and comparison with literature data. Compounds 1 and 2 exhibited the moderate inhibitory activity against Sclerotinia sclerotiorum, Ceratocystis fimbriata and Verticillium dahliae Kleb with MIC values from 50 to 25 μg/mL, and also displayed the weak activity selectively against tested bacteria strains with MIC values from 100 to 50 μg/mL.

Ficus umbellata Vahl. (Moraceae) Stem Bark Extracts Exert Antitumor Activities In Vitro and In Vivo

A Ficus umbellata is used to treat cancer. The present work was therefore designed to assess antitumor potentials of F. umbellata extracts in nine different cell lines. Cell cycle, apoptosis, cell migration/invasion, levels of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), caspases activities as well as Bcl-2 and Bcl-xL protein content were assessed in MDA-MB-231 cells. The 7,12-dimethylbenz(a)anthracene (DMBA)-induced carcinogenesis in rats were also used to investigate antitumor potential of F. umbellata extracts. The F. umbellata methanol extract exhibited a CC50 of 180 μg/mL in MDA-MB-231 cells after 24 h. It induced apoptosis in MCF-7 and MDA-MB-231 cells, while it did not alter their cell cycle phases. Further, it induced a decrease in MMP, an increase in ROS levels and caspases activities as well as a downregulation in Bcl-2 and Bcl-xL protein contents in MDA-MB-231 cells. In vivo, F. umbellata aqueous (200 mg/kg) and methanol (50 mg/kg) extracts significantly (p < 0.001) reduced ovarian tumor incidence (10%), total tumor burden (58% and 46%, respectively), average tumor weight (57.8% and 45.6%, respectively) as compared to DMBA control group. These results suggest antitumor potential of F. umbellata constituents possibly due to apoptosis induction mediated through ROS-dependent mitochondrial pathway.

Manumycin A induces apoptosis in malignant pleural mesothelioma through regulation of Sp1 and activation of the mitochondria-related apoptotic pathway

Manumycin A (Manu A) is a natural product isolated from Streptomyces parvulus and has been reported to have anti-carcinogenic and anti-biotic properties. However, neither its molecular mechanism nor its molecular targets are well understood. Thus, the aim of the present study was to explore the possibility that Manu A has cancer preventive and chemotherapeutic effects on malignant pleural mesothelioma (MPM) through regulation of Sp1 and induction of mitochondrial cell death pathway. Manu A inhibited the cell viability of MSTO-211H and H28 cells in a concentration‑dependent manner as determined by MTS assay. IC50 values were calculated as 8.3 and 4.3 µM in the MSTO-311H and H28 cells following 48 h incubation, respectively. Manu A induced a significant increase in apoptotic indices as shown by DAPI staining, Annexin V assay, multi-caspase activity and mitochondrial membrane potential assay. The downregulation of Sp1 mRNA and protein expression by Manu A led to apoptosis by suppressing Sp1-regulated proteins (cyclin D1, Mcl-1 and survivin). Manu A decreased the protein levels of BID, Bcl-xL and PARP while it increased Bax levels. Manu A caused depolarization of the mitochondrial membrane with induction of CHOP, DR4 and DR5. Our results demonstrated that Manu A exerted anticancer effects by inducing apoptosis via inhibition of the Sp1-related signaling pathway in human MPM.

Hesperidin from Citrus seed induces human hepatocellular carcinoma HepG2 cell apoptosis via both mitochondrial and death receptor pathways

Citrus seeds are full of phenolic compounds, such as flavonoids. The aims of this study were to identify the types of flavonoids in Citrus seed extracts, the cytotoxic effect, mode of cell death, and signaling pathway in human hepatic cancer HepG2 cells. The flavonoids contain anticancer, free radical scavenging, and antioxidant activities. Neohesperidin, hesperidin, and naringin, active flavanone glycosides, were identified in Citrus seed extract. The cytotoxic effect of three compounds was in a dose-dependent manner, and IC50 levels were determined. The sensitivity of human HepG2 cells was as follows: hesperidin > naringin > neohesperidin > naringenin. Hesperidin induced HepG2 cells to undergo apoptosis in a dose-dependent manner as evidenced by the externalization of phosphatidylserine and determined by annexin V-fluorescein isothiocyanate and propidium iodide staining using flow cytometry. Hesperidin did not induce the generation of reactive oxygen species, which was determined by using 2',7'-dichlorohydrofluorescein diacetate and flow cytometry method. The number of hesperidin-treated HepG2 cells with the loss of mitochondrial transmembrane potential increased concentration dependently, using 3,3'-dihexyloxacarbocyanine iodide employing flow cytometry. Caspase-9, -8, and -3 activities were activated and increased in hesperidin-treated HepG2 cells. Bcl-xL protein was downregulated whereas Bax, Bak, and tBid protein levels were upregulated after treatment with hesperidin in a dose-dependent manner. In conclusion, the bioflavanone from Citrus seeds, hesperidin, induced human HepG2 cell apoptosis via mitochondrial pathway and death receptor pathway. Citrus seed flavonoids are beneficial and can be developed as anticancer drug or food supplement, which still needs further in vivo investigation in animals and human beings.