Post-harvest ripening affects drying behavior, antioxidant capacity and flavor release of peach via alteration of cell wall polysaccharides content and nanostructures, water distribution and status.

Effect of post-harvest ripening on cell wall polysaccharides nanostructures, water status, physiochemical properties of peaches and drying behavior under hot air-infrared drying was evaluated. Results showed that the content of water soluble pectins (WSP) increased by 94 %, while the contents of chelate-soluble pectins (CSP), Na2CO3-soluble pectins (NSP) and hemicelluloses (HE) decreased during post-harvest ripening by 60 %, 43 %, and 61 %, respectively. The drying time increased from 3.5 to 5.5 h when the post-harvest time increased from 0 to 6 days. Atomic force microscope analysis showed that depolymerization of hemicelluloses and pectin occurred during post-harvest ripening. Time Domain -NMR observations indicated that reorganization of cell wall polysaccharides nanostructure changed water spatial distribution and cell internal structure, facilitated moisture migration, and affected antioxidant capacity of peaches during drying. This leads to the redistribution of flavor substances (heptanal, n-nonanal dimer and n-nonanal monomer). The current work elucidates the effect of post-harvest ripening on the physiochemical properties and drying behavior of peaches.

Synergism between carnosic acid and arsenic trioxide on induction of acute myeloid leukemia cell apoptosis is associated with modulation of PTEN/Akt signaling pathway.

OBJECTIVE: To investigate the synergistic effects of carnosic acid (CA) with arsenic trioxide (As2O3) on proliferation and apoptosis in HL-60 human myeloid leukemia cells, and the major cellular signaling pathway involved in these effects. METHODS: HL-60 cellular proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) analysis. Cell cycle distribution and apoptosis were monitored by flow cytometry. The activation of casepase-9, Bcl-2-associated agonist of cell death (BAD), p-BAD, p27, phosphatase and tensin homolog deleted on chromosome ten (PTEN), Akt, p-Akt was assessed by Western blot analysis. The expression of PTEN mRNA was tested by reverse transcription polymerase chain reaction (RT-PCR) analysis. RESULTS: CA reduced HL-60 cell viability in a dose- and time-dependent manner, and induced G1 arrest and apoptosis. Moreover, CA upregulated PTEN expression, blocked the Akt signaling pathway, subsequently inhibited phosphorylation of BAD, reactivated caspase-9, and elevated levels of p27. CA also augmented these effects of As2O3. CONCLUSION: CA might be a novel candidate of the combination therapy for leukemia treatment; these effects were apparently associated with the modulation of PTEN/Akt signaling pathway.

Reversion of P-glycoprotein-mediated multidrug resistance in human leukemic cell line by carnosic acid.

One of the common hindrances to successful chemotherapy is the development of multidrug resistance (MDR) by tumor cells to multiple chemotherapeutic agents. In this regard, P-glycoprotein (P-gp) acts as an energized drug pump that reduces the intracellular concentration of drugs, even of structurally unrelated ones. The modulators of P-gp function can restore the sensitivity of MDR cells to anticancer drugs. Therefore, to develop effective drug-resistance-reversing agents, we evaluated the P-gp modulating potential of carnosic acid (CA) in multidrug-resistant K562/AO2 cells in the present study. The reversing effect of CA was evaluated by determining the inhibition rates of cell viability with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assays. The intracellular adriamycin fluorescence intensity and the expression of P-gp were measured by flow cytometry (FCM). Meanwhile, the subcellular distribution of adriamycin was detected via Laser Scanning Confocal Microscopy (LSCM). The mRNA expression of mdrlwas then detected via semiquantitative reverse transcription polymerase chain reaction (RT-PCR). The findings showed that CA decreased apparently the Inhibition Concentration 50% (IC50) of adriamycin by increasing its intracellular concentration and thus enhancing the sensitivity of K562/AO2 cells. Adriamycin was distributed evenly in the cytoplasm when the cells were treated with CA. The expression of mdrl was decreased. Overall, the results indicated that CA can serve as a novel, non-toxic modulator of MDR, and it can reverse the MDR of K562/AO2 cells in vitro by increasing intracellular adriamycin concentration, down-regulating the expression of mdrl, and inhibiting the function of P-gp.