Background: Adansonia digitata L. (Malvaceae), also known as baobab, is a tree attracting recent interest especially due to the high nutritional value of the fruit pulp. However, few studies are reported on the secondary metabolite content, showing high variability depending on the geographic region. Methods: In this study, the chemical profiles of Malian commercial baobab fruits and leaves, focused on phenolic content, were investigated by HPLC coupled with a photodiode array (PDA)/UV and an electrospray ionization (ESI) mass spectrometer (MS) and gas chromatography (GC)/MS. In addition, the extracts of fruit pulps obtained from three different markets (Fruits 1, 2, and 3) were evaluated for their total phenolic content (TPC), antioxidant activity and α-glucosidase inhibition. Results: Baobab fruit pulps were found to be rich in procyanidins and flavonol glycosides, with tiliroside as the major constituent. The baobab leaves showed a similar profile respect to the fruits, but with more detected phenolics. All fruit pulp extracts exerted antioxidant activity (highest for Fruit 3) and higher α-glucosidase inhibition than acarbose used as standard. Conclusions: This study confirmed the variability of baobab with different origins and indicated Malian species baobab as a promising source of health-promoting substances.

Overproduction of oxidants in the human body is responsible for oxidative stress, which is associated with several diseases. High intake of vegetables and fruits can reduce the risk of chronic diseases, as they are sources of bioactive compounds capable of contrasting the free radical effects involved in cancer, obesity, diabetes, and neurodegenerative and cardiovascular diseases. Capsicum annuum L. cv Senise is a sweet pepper that is grown in the Basilicata region (Italy). It is an important source of polyphenols, carotenoids, and capsinoids and can play a key role in human health. In this study, an ethanol extract was obtained from C. annuum dried peppers and the analysis of the phytochemical composition was performed by LC-ESI/LTQ Orbitrap/MS. The extract was incorporated into liposomes, which showed small size (~80 nm), good homogeneity, negative surface charge, and good stability in storage. The biological activity of the extract was evaluated in the human hepatoma (HepG2) cell line, used as model cells. The extract showed no cytotoxic activity and reduced the intracellular reactive oxygen species (ROS) level in stressed cells. The antioxidant activity was further improved when the extract was loaded into liposomes. Moreover, the extract promoted the expression of endogenous antioxidants, such as catalase, superoxide dismutase, and glutathione peroxidase through the Nrf-2 pathway evaluated by RT-PCR.

The first intermediate in the mitochondrial tricarboxylic acid (TCA) cycle is citrate, which is essential and acts as a metabolic regulator for glycolysis, TCA cycle, gluconeogenesis, and fatty acid synthesis. Within the cytosol, citrate is cleaved by ATP citrate lyase (ACLY) into oxaloacetate (OAA) and acetyl-CoA; OAA can be used for neoglucogenesis or in the TCA cycle, while acetyl-CoA is the precursor of some biosynthetic processes, including the synthesis of fatty acids. Accumulating evidence suggests that citrate is involved in numerous physiological and pathophysiological processes such as inflammation, insulin secretion, neurological disorders, and cancer. Considering the crucial role of citrate to supply the acetyl-CoA pool for fatty acid synthesis and histone acetylation in tumors, in this study we evaluated the effect of citrate added to the growth medium on lipid deposition and histone H4 acetylation in hepatoma cells (HepG2). At low concentration, citrate increased both histone H4 acetylation and lipid deposition; at high concentration, citrate inhibited both, thus suggesting a crucial role of acetyl-CoA availability, which prompted us to investigate the effect of citrate on ACLY. In HepG2 cells, the expression of ACLY is correlated with histone acetylation, which, in turn, depends on citrate concentration. A decrease in H4 acetylation was also observed when citrate was added at a high concentration to immortalized human hepatic cells, whereas ACLY expression was unaffected, indicating a lack of control by histone acetylation. Considering the strong demand for acetyl-CoA but not for OAA in tumor cells, the exogenous citrate would behave like a trojan horse that carries OAA inside the cells and reduces ACLY expression and cellular metabolism. In addition, this study confirmed the already reported dual role of citrate both as a promoter of cell proliferation (at lower concentrations) and as an anticancer agent (at higher concentrations), providing useful tips on the use of citrate for the treatment of tumors.

The purpose of this study was to improve the knowledge on Hura crepitans L., a plant belonging to the Euphorbiaceae family that, on the one hand, is known to be toxic, but on the other, is a source of polyphenols with health-promoting effects. Different green extraction methods were applied, varying solvent, temperature, and duration of extraction, which can influence the phytochemical profile and biological activity of plant extracts, and the extracts were fully characterized. Aqueous extracts exhibited a superior antioxidant activity, as indicated by different spectrophotometric tests, and were cytoprotective to HepG2 cells used as model cells. Liquid chromatography–mass spectrometry analyses were performed to identify the secondary metabolites involved in these effects and demonstrated that solvent, duration, and temperature indeed influenced the extraction of polyphenols. Furthermore, the most promising extract, in terms of antioxidant potential, was incorporated into liposomes with the aim of promoting cell interaction and enhancing the antioxidant activity.

Quercetin is a member of the flavonoid group of compounds, which is abundantly present in various dietary sources. It has excellent antioxidant properties and anti-inflammatory activity and is very effective as an anti-cancer agent against various types of tumors, both in vivo and in vitro. Quercetin has been also reported to modulate the activity of some members of the multidrug-resistance transporters family, such as P-gp, ABCC1, ABCC2, and ABCG2, and the activity of ecto-5′-nucleotidase (NT5E/CD73), a key regulator in some tumor processes such as invasion, migration, and metastasis. In this study, we investigated the effect of Quercetin on ABCC6 expression in HepG2 cells. ABCC6 is a member of the superfamily of ATP-binding cassette (ABC) transporters, poorly involved in drug resistance, whose mutations cause pseudoxanthoma elasticum, an inherited disease characterized by ectopic calcification of soft connective tissues. Recently, it has been reported that ABCC6 contributes to cytoskeleton rearrangements and HepG2 cell motility through purinergic signaling. Gene and protein expression were evaluated by quantitative Reverse-Transcription PCR (RT-qPCR) and western blot, respectively. Actin cytoskeleton dynamics was evaluated by laser confocal microscopy using fluorophore-conjugated phalloidin. Cell motility was analyzed by an in vitro wound-healing migration assay. We propose that ABCC6 expression may be controlled by the AKT pathway as part of an adaptative response to oxidative stress, which can be mitigated by the use of Quercetin-like flavonoids.