Apoptotic, Anti-Inflammatory Activities and Interference with the Glucocorticoid Receptor Signaling of Fractions from Pistacia lentiscus L. var. chia Leaves

Abstract

In this study acetonic extracts of leaves of Pistacia lentiscus L. var. chia (mastiha tree) grown in the south as well as in the north Chios Greek island were isolated and further fractionated to give three different polarity fractions: apolar, medium-polar, and polar. The isolated fractions were assessed as regards their main composition, cytotoxic, anti-inflammatory activities, and interference with the glucocorticoid receptor (GR) signaling, applying cytotoxic assay, luciferase assays, and Western blot analysis of apoptosis-, energy-, and inflammation-associated molecules. Differences in cell viability have been detected among different polarity leaf fractions as well as among fractions of different plant origin with polar fractions showing the highest cytotoxicity. Fractions-induced anti-inflammatory activities and suppressive effects on the dexamethasone (DEX)-induced GR transcriptional activation were unveiled. The partition protocol of leaves fractions applied uncovers the enhanced glucocorticoid-associated biological activities of the medium-polar fractions, which may be associated with their enrichment in the triterpenoids that showed structural similarity with the glucocorticoids. A reduction in GR protein levels is observed by the fraction which is shown to be associated with the medium polar-induced proteolytic degradation of the receptor. In addition, the enhanced cytotoxic, anti-inflammatory, and potential anti-glycemic activities of the fractions from the Southern P. lentiscus L. that exclusively produce the mastiha resin, is revealed, indicating that leaves fractions from mastiha tree, similarly to mastiha tree resin, may have the potential to be further analyzed for their potent applications in the pharmaceutical cosmetic and nutraceutical fields.

Regulation of Energy Metabolism and Anti-Inflammatory Activities of Mastiha Fractions from Pistacia lentiscus L. var. chia

“…This latter suspension was completely evaporated at reduced pressure. The powder obtained after evaporation was stratified on a Celite layer, as previously described [ 20 ]. Three different polarity fractions were then isolated by the addition of solvents of increasing polarity (petroleum ether (Pe), ethyl acetate (EtOAc), and tetrahydrofuran (THF)), as previously described [ 20 ].…”

“…The powder obtained after evaporation was stratified on a Celite layer, as previously described [ 20 ]. Three different polarity fractions were then isolated by the addition of solvents of increasing polarity (petroleum ether (Pe), ethyl acetate (EtOAc), and tetrahydrofuran (THF)), as previously described [ 20 ]. The three vacuum filtrates were collected and evaporated to obtain 1.91 g of apolar fraction (ap) (20.1% yield, Pe extract), 5.81 g of medium-polar fraction (mp) (61.2% yield, EtOAc extract), and 0.56 g of polar fraction (p) (5.9% yield, THF extract).…”

“…HEK293 cells were plated in 96-well plate at a density of 1.5 × 10 4 cells/well for 24 h in DMEM, supplemented with 10% FBS, 2 mM L-glutamine, and 100 units/mL pen/strep, as previously described [ 20 ]. Cells were then treated with resin fractions diluted in 100% DMSO.…”

“…Our previous studies also showed that the medium-polar and the polar fractions from Pistacia lentiscus L. var. chia leaves interfere with GR signaling via repression of GR transcriptional activation and the reduction of its protein levels in a proteasomal-dependent manner [ 20 ].…”

Encapsulating silybin in PCL-based electrospun nanofibers

“…To evaluate the amount of loaded silybin, the prepared nanofibers were initially dissolved and the amount of released silybin was measured using ultraviolet–visible (UV-Vis) spectrophotometry. Τhe potential cytotoxic activity of the composite scaffolds was assessed in human embryonic kidney HEK-293 3 and in human hepatocarcinoma HepG2 cells 4 , applying the MTT assay. A conspicuous inhibition effect of silybin-encapsulated nanofibers against the carcinoma cell line was observed, underlying the antitumor potential that the electrospun polymer composites exhibit.…”