Increased consumption of fruit and vegetables can represent an easy strategy to significantly reduce the incidence of cancer. We recently demonstrated that the flavonoid quercetin, naturally present in the diet and belonging to the class of phytochemicals, is able to sensitize several leukemia cell lines and B cells isolated from patients affected by chronic lymphocytic leukemia (B‐CLL), in addition to apoptotic inducers (anti‐CD95 and rTRAIL). Further, it potentiates the effect of fludarabine, a first‐line chemotherapeutic drug used against CLL. The proapoptotic activity of quercetin in cell lines and B‐CLL is related to the expression and activity of Mcl‐1–antiapoptotic proteins belonging to the Bcl‐2 family. Quercetin downregulates Mcl‐1 mRNA and protein levels acting on mRNA stability and protein degradation. Considering the low toxicity of the flavonoids toward normal peripheral blood cells, our experimental results are in favor of a potential use of quercetin in adjuvant chemotherapy in CLL or other types of cancer.

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The underutilised forest and industrial biomass of Castanea sativa (Mill.) is generally discarded during post-harvest and food processing, with high impact on environmental quality. The searching on alternative sources of natural antioxidants from low-cost supplies, by methods involving environment-friendly techniques, has become a major goal of numerous researches in recent times. The aim of the present study was the set-up of a biomolecules extraction procedure from chestnut leaves, burs and shells and the assessing of their potential antioxidant activity. Boiling water was the best extraction solvent referring to polyphenols from chestnut shells and burs, whereas the most efficient for leaves resulted 60% ethanol at room temperature. Greatest polyphenol contents were 90.35, 60.01 and 17.68 mg gallic acid equivalents g in leaves, burs and shells, respectively. Moreover, flavonoids, tannins and antioxidant activity were assessed on the best extract obtained from each chestnut by-product.

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Three isozymes of pectin methylesterase (EC 3.1.1.11) have been purified to homogeneity from tomato (var. S. marzano). The isozymes were separated by affinity chromatography on Heparin‐Sepharose column. They exhibited a molecular mass of 31 kDa when analyzed in sodium dodecyl sulfate gel electrophoresis and of 35 kDa in gel‐filtration chromatography in native conditions. The isoelectric points of all three isozymes were found to be higher than 9.3. The Kms calculated for the three isozymes were different toward citrus pectin used as substrate; one had a Km of 9.7 mM (by expressing the pectin concentration as mmoles/L of methoxy groups) and the other two had similar Kms of 3.0 and 2.6 mM, respectively. The isozyme having the higher Km for substrate was inhibited by citrus pectin (which had a degree of methylation of 70%) at concentrations higher than 5 mM, but no inhibition was found using a pectin with a degree of methylation of 30% at concentrations up to 13 mM (i.e. 9 mg/ml) with a Km of 14.7 mM. Furthermore, this isozyme showed a more broad range of activity in a pH range 5–10 with respect to that exhibited by the other two isozymes. All three isozymes were found to be glycosylated, although to different extents.