Interaction of Artepillin C with model membranes

Mechanistic Understanding from Molecular Dynamics in Pharmaceutical Research 2: Lipid Membrane in Drug Design

We review the use of molecular dynamics (MD) simulation as a drug design tool in the context of the role that the lipid membrane can play in drug action, i.e., the interaction between candidate drug molecules and lipid membranes. In the standard "lock and key" paradigm, only the interaction between the drug and a specific active site of a specific protein is considered; the environment in which the drug acts is, from a biophysical perspective, far more complex than this. The possible mechanisms though which a drug can be designed to tinker with physiological processes are significantly broader than merely fitting to a single active site of a single protein. In this paper, we focus on the role of the lipid membrane, arguably the most important element outside the proteins themselves, as a case study. We discuss work that has been carried out, using MD simulation, concerning the transfection of drugs through membranes that act as biological barriers in the path of the drugs, the behavior of drug molecules within membranes, how their collective behavior can affect the structure and properties of the membrane and, finally, the role lipid membranes, to which the vast majority of drug target proteins are associated, can play in mediating the interaction between drug and target protein. This review paper is the second in a two-part series covering MD simulation as a tool in pharmaceutical research; both are designed as pedagogical review papers aimed at both pharmaceutical scientists interested in exploring how the tool of MD simulation can be applied to their research and computational scientists interested in exploring the possibility of a pharmaceutical context for their research.

Artepillin C as an outstanding phenolic compound of Brazilian green propolis for disease treatment: A review on pharmacological aspects

Propolis is a viscous resin consisting of plant material (shoots, flowers, and plant exudates), salivary secretions and waxes produced by Apis mellifera bees. Its popular use aroused the interests of scientific research, which proved to be a potential source of various bioactive substances. The chemical composition of propolis depends on several factors, such as the different types of plant sources collected by bees, geographic origin, and the time of year in which they are produced, but it is known that phenolic represent the main bioactive constituents of propolis. Baccharis dracunculifolia DC (Asteraceae) is the most important botanical source of propolis and a native to southeastern Brazil. It is widely known as the green propolis because of its deep green color. One of its major phenolic acids is artepillin C (Art-C), a diprenyl-p-hydroxycinnamic acid derivative. This review aims to provide a comprehensive summary of the pharmacological effects of Art-C. The limited number of publications on this topic over the past two decades have been collected from databases and summarized. Numerous biological activities have been described for the Art-C, such as gastroprotective, anti-inflammatory, antimicrobial, antioxidant, antitumor. This article describes aspects of occurrence, synthesis, biological activities and pharmacokinetic approaches.

Artepillin C: A comprehensive review of its chemistry, bioavailability, and pharmacological properties

Artepillin C (ARC), a prenylated derivative of p-coumaric acid, is one of the major phenolic compounds found in Brazilian green propolis (BGP) and its botanical source Baccharis dracunculifolia. Numerous studies on ARC show that its beneficial health effects correlate with the health effects of both BGP and B. dracunculifolia. Its wide range of pharmacological benefits include antioxidant, antimicrobial, anti-inflammatory, anti-diabetic, neuroprotective, gastroprotective, immunomodulatory, and anti-cancer effects. Most studies have focused on anti-oxidation, inflammation, diabetic, and cancers using both in vitro and in vivo approaches. Mechanisms underlying anti-cancer properties of ARC are apoptosis induction, cell cycle arrest, and the inhibition of p21-activated kinase 1 (PAK1), a protein characterized in many human diseases/disorders including COVID-19 infection. Therefore, further pre-clinical and clinical studies with ARC are necessary to explore its potential as intervention for a wide variety of diseases including the recent pandemic coronaviral infection. This review summarizes the comprehensive data on the pharmacological effects of ARC and could be a guideline for its future study and therapeutic usage.

Novel lipophilic SN38 prodrug forming stable liposomes for colorectal carcinoma therapy

Background: SN38 (7-ethyl-10-hydroxy camptothecin), as a potent metabolite of irinotecan, is highly efficacious in cancer treatment. However, the clinical utility of SN38 has been greatly limited due to its undesirable properties, such as poor solubility and low stability.

Materials and methods: In order to overcome these weaknesses, moeixitecan, a lipophilic SN38 prodrug containing a SN-38, a trolox, a succinic acid linker, and a hexadecanol chain, was loaded into liposomal nanoparticles by ethanol injection method.

Results: Experiments showed that the moeixitecan-loaded liposomal nanoparticles (MLP) with a diameter of 105.10±1.49 nm have a satisfactory drug loading rate (90.54±0.41%), high solubility and stability, and showed sustained release of SN38. Notably, MLP exhibited better antitumor activity against human colon adenocarcinoma cells than irinotecan, a FDA-approved drug for the treatment of advanced colorectal cancer. Furthermore, xenograft model results showed that MLP outperformed irinotecan in terms of pharmacokinetics, in vivo therapeutic efficacy and safety. Finally, we used molecular dynamic simulations to explore the association between the structure of MLP and the physical and functional properties of MLP, moeixitecan molecules in MLP folded themselves inside the hydrocarbon chain of the lipid bilayer, which led an increased acyl chain order of the lipid bilayer, and therefore enhanced the lactone ring stability protecting it from hydrolysis.

Conclusion: Our MLP constructing strategy by liposome engineering technology may serve a promising universal approach for the effective and safe delivery of lipophilic prodrug.

Effects of artepillin C on model membranes displaying liquid immiscibility

It has been hypothesized that the therapeutic effects of artepillin C, a natural compound derived from Brazilian green propolis, are likely related to its partition in the lipid bilayer component of biological membranes. To test this hypothesis, we investigated the effects of the major compound of green propolis, artepillin C, on model membranes (small and giant unilamelar vesicles) composed of ternary lipid mixtures containing cholesterol, which display liquid-ordered (l_o) and liquid-disordered (l_d) phase coexistence. Specifically, we explored potential changes in relevant membrane parameters upon addition of artepillin C presenting both neutral and deprotonated states by means of small angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), and confocal and multiphoton excitation fluorescence microscopy. Thermotropic analysis obtained from DSC experiments indicated a loss in the lipid cooperativity of l_o phase at equilibrium conditions, while at similar conditions spontaneous formation of unilamellar vesicles from SAXS experiments showed that deprotonated artepillin C preferentially located at the surface of the membrane. Time-resolved experiments using fluorescence microscopy showed that at doses above 100 µM, artepillin C in its neutral state interacted with both liquid-ordered and liquid-disordered phases, inducing curvature stress and promoting dehydration at the membrane interface.

Chemical characterization, antioxidant and antimicrobial activity of propolis obtained from Melipona quadrifasciata quadrifasciata and Tetragonisca angustula stingless bees

In this study, we investigated the chemical composition, and antioxidant and antibacterial properties of ethanolic extracts of propolis (EEP) from Melipona quadrifasciata quadrifasciata and Tetragonisca angustula. Chemical composition of EEP was determined by colorimetry and chromatographic (HPLC-DAD and UPLC-Q/TOF-MS/MS) analysis. Antimicrobial activity of EEP was evaluated against gram-positive (S. aureus, methicillin-resistant S. aureus, E. faecalis) and gram-negative (E. coli and K. pneumoniae) bacteria by the minimal inhibitory concentration (MIC) test using the microdilution method. Furthermore, the growth curve and integrity of cell membrane of S. aureus and E. coli were investigated using standard microbiological methods. HPLC-DAD analysis showed that the EEP of M. quadrifasciata quadrifasciata has a more complex chemical composition than the EEP of T. angustula. Moreover, UPLC-MS analyses of M. quadrifasciata quadrifascita indicated flavonoids and terpenes as major constituents. The bactericidal activity of both EEPs was higher against gram-positive bacteria than for gram-negative bacteria. The EEP from M. quadrifasciata quadrifasciata presented MIC values lower than the EEP from T. angustula for all tested bacteria. The EEP from M. quadrifasciata quadrifasciata caused lysis of the bacterial wall and release of intracellular components from both E. coli and S. aureus. Our findings indicate that the chemical composition of propolis from stingless bees is complex and depends on the species. The extract from M. quadrifasciata quadrifascita was more effective against gram-positive than gram-negative strains, especially against S. aureus and methicillin-resistant S. aureus compared to T. angustula extract, by a mechanism that involves disturbance of the bacterial cell membrane integrity.