Immunobiological properties of selected natural and chemically modified phenylpropanoids

Comprehensive Characterization of Chemical Composition and Antioxidant Activity of Lignan-Rich Coniferous Knotwood Extractives

A knotwood of coniferous trees containing large amounts of polyphenolic extractives is considered a promising industrial-scale source of lignans possessing antioxidant properties and other bioactivities. The present study is aimed at a detailed characterization of the chemical composition and antioxidant activity of lignan-rich extractives obtained from the knotwood of the Norway spruce, Scotch pine, Siberian fir, and Siberian larch growing in the European North of Russia as a region with a highly developed forest industry. To achieve this, a comprehensive approach based on a combination of two-dimensional NMR spectroscopy with high-performance liquid chromatography-high-resolution Orbitrap mass spectrometry, and the determination of antioxidant activity by the three complementary methods were proposed. The studied knotwood samples contained from 3.9 to 17% of extractive substances and were comparable to Trolox's antioxidant activity in the single-electron transfer processes and superoxide radical scavenging, which is associated with the predominance of polyphenolic compounds. The latter was represented by 12 tentatively identified monolignans and 27 oligolignans containing 3-5 phenylpropane units in their structure. The extracts were characterized by an identical set of lignans and differed only in the ratios of their individual compounds. Other components of the knotwood were flavonoids taxifolin, quercetin (Siberian larch), and three stilbenes (pinosylvin, its methyl ester, and pterostilbene), which were identified in the Scotch pine extractives. Sesquiterpene juvabione and its derivatives were found in extracts of Siberian larch knotwood.

Chitosan/poly (lactic acid)-coated piceatannol nanoparticles exert an in vitro apoptosis activity on liver, lung and breast cancer cell lines

The aim of the study was to synthesize nanoparticles (NPs) with chitosan (CS), and poly (lactic acid) (PLA) as a carrier for the drug piceatannol (PIC). The synthesized nanoparticles form the composite of polymeric-drug nanoparticles (CS/PLA-PIC NPs) by dropping method. The preliminary and stability studies were determined for the polymers drug-loading capacity and encapsulation efficiencies. The in vitro drug release study showed that NPs provided a continuous release of the entrapped PIC. The NPs found to be a good scavenger for DPPH, SOD and NO radicals. MTT and LDH assays revealed higher cytotoxic efficacy of CS/PLA-PIC NPs in HepG2, A549 and MCF7 cells compared to CS-PLA NPs and PIC. Dual staining results showed the early/late-stages of apoptotic and necrotic cells. Furthermore, cells treated with CS/PLA-PIC NPs showed fragmenting DNA and also demonstrated for apoptotic cells percentage by flow cytometry. These results suggested that upon CS/PLA-PIC NPs exposure leads to decrease in cancer cell viability due to apoptosis.

A Comprehensive Review on the Chemotherapeutic Potential of Piceatannol for Cancer Treatment, with Mechanistic Insights

Cancer is a diverse class of diseases characterized by uncontrolled cell growth that constitutes the greatest cause of mortality and morbidity worldwide. Despite steady progress, the treatment modalities of cancer are still insufficient. Several new concepts have emerged for therapeutic intervention in malignant diseases with the goal of identifying specific targets and overcoming resistance against current cytotoxic therapies. Many studies have reported the remarkable and significant properties of dietary plant polyphenols such as curcumin, resveratrol, flavopiridol, indirubin, magnolol, piceatannol, parthenolide, epigallocatechin gallate, and cucurbitacin as anticancer agents known for their pleiotropic effects on cancer, immune cells, and inflammation. Piceatannol, an analogue and metabolite of resveratrol, is a natural stilbene commonly found in grape skins and wine. Compared to resveratrol, this molecule exhibits superior bioactivities as an inhibitor of COX-1/2 and the CSN-associated kinase. Piceatannol is thought to be a potent natural compound with many therapeutic effects, such as the prevention of hypercholesterolemia, arrhythmia, atherosclerosis, angiogenesis, and cardiovascular diseases. It also demonstrates vasorelaxation, antioxidant, and anticancer activities. This comprehensive review summarizes the current data regarding the mechanisms of action of piceatannol, its chemopreventive properties, and its possible therapeutic potential against various types of human cancer.

Immunobiological properties of sesquiterpene lactones obtained by chemically transformed structural modifications of trilobolide

Our previous research on immunostimulatory properties of trilobolide and its structurally related natural analogues isolated from Laser trilobum (L.) Borkh., encouraged us to investigate structurally related guaianolides belonging to a specific group of sesquiterpene lactones with characteristic glycol moiety attached to the lactone ring. Ever increasing attention has been paid to certain guaianolides such as thapsigargin and trilobolide for their promising anti-inflammatory, anticancer, anti-infectious and SERCA inhibitory activities. However, due to their alkylation capabilities, they might be cytotoxic. Search for compounds with preserved immunobiological properties and decreased cytotoxicity led us to transform some of their structural features, particularly those related to their side chain functionality. For this reason, we prepared a series of over 20 various deacylated, acyl modified, or relactonized derivatives of trilobolide. The immunobiological effects were screened in vitro using the rat peritoneal cells primed with lipopolysaccharide. Secretion of interferon-γ (IFN-γ), interleukins (IL) IL-1β, IL-6 and tumour necrosis factor-α (TNF-α) were determined by ELISA, and nitric oxide (NO) production by Griess reagent. Relation between the molecular structure and immunobiological activity was investigated. Acetylation at 7-OH and 11-OH positions of the lactone ring, or acyl modification of the guaianolide functionalities (including relactonization) of trilobolide, led to inability to stimulate secretion of cytokines and production of NO. Interestingly, minor structural changes achieved by catalytic hydrogenation or hydrogenolysis retained the original immunoactivity of trilobolide. It can be concluded that several new chemically transformed sesquiterpene lactones resembling the immunobiological properties of trilobolide or thapsigargin were prepared and identified. The implication of the lactone vicinal diol (glycol) moiety, combined with other structure functionality, was confirmed as essential for immune properties of the trilobolide or thapsigargin type of guaianolides.

Decreased activity and accelerated apoptosis of neutrophils in the presence of natural polyphenols

Prolonged or excessive formation and liberation of cytotoxic substances from neutrophils intensifies inflammation and the risk of tissue damage. From this perspective, administration of substances which are able to reduce activity of neutrophils and to enhance apoptosis of these cells may improve the therapy of pathological states connected with persistent inflammation. In this short review, neutrophil oxidative burst and apoptosis are presented as potential targets for pharmacological intervention. Effects of natural polyphenols (resveratrol, pterostilbene, pinosylvin, piceatannol, curcumin, N-feruloylserotonin) are summarised, considering the ability of these compounds to affect inflammation and particularly neutrophil activity. The intended neutrophil inhibition is introduced as a part of a new strategy for pharmacological modulation of chronic inflammatory processes, focused on supporting innate anti-inflammatory mechanisms and enhancing resolution of inflammation.

Pharmacological influence on processes of adjuvant arthritis: Effect of the combination of an antioxidant active substance with methotrexate

Oxygen metabolism has an important role in the pathogenesis of rheumatoid arthritis. A certain correlation was observed between oxidative stress, arthritis and the immune system. Reactive oxygen species produced in the course of cellular oxidative phosphorylation and by activated phagocytic cells during oxidative burst, exceed the physiological buffering capacity and result in oxidative stress. The excessive production of ROS can damage protein, lipids, nucleic acids, and matrix components. Patients with rheumatoid arthritis have an altered antioxidant defense capacity barrier. In the present study the effect of substances with antioxidative properties, i.e. pinosylvin and carnosine, was determined in monotherapy for the treatment of adjuvant arthritis (AA). Moreover carnosine was evaluated in combination therapy with methotrexate. Rats with AA were administered first pinosylvin (30 mg/kg body mass daily per os), second carnosine (150 mg/kg body mass daily per os) in monotherapy for a period of 28 days. Further, rats with AA were administered methotrexate (0.3 mg/kg body mass 2-times weekly per os), and a combination of methotrexate+carnosine, with the carnosine dose being the same as in the previous experiment. Parameters, i.e. changes in hind paw volume and arthritic score were determined in rats as indicators of destructive arthritis-associated clinical changes. Plasmatic levels of TBARS and lag time of Fe²⁺-induced lipid peroxidation (tau-FeLP) in plasma and brain were specified as markers of oxidation. Plasmatic level of CRP and activity of γ-glutamyltransferase (GGT) in spleen and joint were used as inflammation markers. In comparison to pinosylvin, administration of carnosine monotherapy led to a significant decrease in the majority of the parameters studied. In the combination treatment with methotrexate+carnosine most parameters monitored were improved more remarkably than by methotrexate alone. Carnosine can increase the disease-modifying effect of methotrexate treatment in rat AA.

The natural stilbenoid pinosylvin and activated neutrophils: effects on oxidative burst, protein kinase C, apoptosis and efficiency in adjuvant arthritis

AIM

To investigate the effects of the naturally occurring stilbenoid pinosylvin on neutrophil activity in vitro and in experimental arthritis, and to examine whether protein kinase C (PKC) activation served as an assumed target of pinosylvin action.

METHODS

Fresh human blood neutrophils were isolated. The oxidative burst of neutrophils was evaluated on the basis of enhanced chemiluminescence. Neutrophil viability was evaluated with flow cytometry, and PKC phosphorylation was assessed by Western blotting analysis. Adjuvant arthritis was induced in Lewis rats with heat-killed Mycobacterium butyricum, and the animals were administered with pinosylvin (30 mg/kg, po) daily for 21 d after arthritis induction.

RESULTS

In isolated human neutrophils, pinosylvin (10 and 100 μmol/L) significantly decreased the formation of oxidants, both extra- and intracellularly, and effectively inhibited PKC activation stimulated by phorbol myristate acetate (0.05 μmol/L). The inhibition was not due to neutrophil damage or increased apoptosis. In arthritic rats, the number of neutrophils in blood was dramatically increased, and whole blood chemiluminescence (spontaneous and PMA-stimulated) was markedly enhanced. Pinosylvin administration decreased the number of neutrophils (from 69 671 ± 5588/μL to 51 293 ± 3947/μL, P=0.0198) and significantly reduced the amount of reactive oxygen species in blood.

CONCLUSION

Pinosylvin is an effective inhibitor of neutrophil activity, and is potentially useful as a complementary medicine in states associated with persistent inflammation.