Antioxidant effects of betulin on porcine chondrocyte behavior in gelatin/C6S/C4S/HA modified tricopolymer scaffold

Dual Functional Antibacterial-Antioxidant Core/Shell Alginate/Poly(ε-caprolactone) Nanofiber Membrane: A Potential Wound Dressing

Core/shell nanofibers offer the advantage of encapsulating multiple drugs with different hydrophilicity in the core and shell, thus allowing for the controlled release of pharmaceutic agents. Specifically, the burst release of hydrophilic drugs from such fiber membranes causes an instantaneous high drug concentration, whereas a long and steady release is usually desired. Herein, we tackle the problem of the initial burst release by the generation of core/shell nanofibers with the hydrophilic antibiotic drug gentamycin loaded within a hydrophilic alginate core surrounded by a hydrophobic shell of poly(ε-caprolactone). Emulsion electrospinning was used as the nanofibrous mesh generation procedure. This process also allows for the loading of a hydrophobic compound, where we selected a natural antioxidant molecule, betulin (BTL), to detoxify the radicals. The resulting nanofibers exhibited a cylindrical shape with a core/shell structure. In vitro tests showed a controlled release of gentamicin from nanofibers via diffusion. The drug reached 93% release in an alginate hydrogel film but only 50% release in the nanofibers, suggesting its potential to minimize the initial burst release. Antibacterial tests revealed significant activity against both Gram-negative and Gram-positive bacteria. The antioxidant property of betulin was confirmed through the DPPH assay, where the incorporation of 20% BTL revealed 37.3% DPPH scavenging. The nanofibers also exhibited favorable biocompatibility in cell culture studies, and no harmful effects on cell viability were observed. Overall, this research offers a promising approach to producing core/shell nanofibrous mats with antibacterial and antioxidant properties, which could effectively address the requirements of wound dressings, including infection prevention and wound healing acceleration.

Betulin Stimulates Osteogenic Differentiation of Human Osteoblasts-Loaded Alginate-Gelatin Microbeads

Osteoporosis, a terminal illness, has emerged as a global public health problem in recent years. The long-term use of bone anabolic drugs to treat osteoporosis causes multi-morbidity in elderly patients. Alternative therapies, such as allogenic and autogenic tissue grafts, face important issues, such as a limited source of allogenic grafts and tissue rejection in autogenic grafts. However, stem cell therapy has been shown to increase bone regeneration and decrease osteoporotic bone formation. Stem cell therapy combined with betulin (BET) supplementation might be adequate for bone remodeling and new bone tissue generation. In this study, the effect of BET on the viability and osteogenic differentiation of hFOB 1.19 cells was investigated. The cells were encapsulated in alginate-gelatin (AlGel) microbeads. In vitro tests were conducted during the 12 d of incubation. While BET showed cytotoxic activity (>1 µM) toward non-encapsulated hFOB 1.19 cells, encapsulated cells retained their functionality for up to 12 days, even at 5 µM BET. Moreover, the expression of osteogenic markers indicates an enhanced osteo-inductive effect of betulin on encapsulated hFOB 1.19, compared to the non-encapsulated cell culture. The 3D micro-environment of the AlGel microcapsules successfully protects the hFOB 1.19 cells against BET cytotoxicity, allowing BET to improve the mineralization and differentiation of osteoblast cells.

Pharmacological Potential of Betulin as a Multitarget Compound

Betulin is a natural triterpene, usually from birch bark, known for its potential wound-healing properties. Despite having a wide range of pharmacological targets, no studies have proposed betulin as a multitarget compound. Betulin has protective effects against cardiovascular and liver diseases, cancer, diabetes, oxidative stress, and inflammation. It reduces postprandial hyperglycemia by inhibiting α-amylase and α-glucosidase activity, combats tumor cells by inducing apoptosis and inhibiting metastatic proteins, and modulates chronic inflammation by blocking the expression of proinflammatory cytokines via modulation of the NFκB and MAPKs pathways. Given its potential to influence diverse biological networks with high target specificity, it can be hypothesized that betulin may eventually become a new lead for drug development because it can modify a variety of pharmacological targets. The summarized research revealed that the diverse beneficial effects of betulin in various diseases can be attributed, at least in part, to its multitarget anti-inflammatory activity. This review focuses on the natural sources, pharmacokinetics, pharmacological activity of betulin, and the multi-target effects of betulin on signaling pathways such as MAPK, NF-κB, and Nrf2, which are important regulators of the response to oxidative stress and inflammation in the body.

Synthesis and Fabrication of a Betulin-Containing Polyolefin Electrospun Fibrous Mat for Antibacterial Applications

Biocompounds play a significant role in the area of renewable polymers in terms of sustainability, as they can be employed or converted into monomers for polymerization in a manner similar to many petroleum-derived monomers. In this work, betulin, a plant-derived triterpene with antibacterial and antiviral properties, was converted to two kinds of α,ω-diene derivatives with different methylene spacer lengths between the olefin and the ester group via an esterification reaction. Polyolefins were subsequently made by acyclic diene metathesis (ADMET) polymerization of betulin-based α,ω-diene. The polymer consists of rigid betulin and flexible unsaturated aliphatic segments, which was confirmed by NMR spectroscopy and gel permeation chromatography (GPC). The influence of different parameters including temperature, catalysts, and catalyst loading on ADMET polymerization was investigated. These polyolefins with high molar mass (up to 20.0 kg/mol) were obtained in an elevated yield (≥95%). Thermal analysis of these (co)polymers showed excellent thermal stability (up to 360 °C) and tunable glass transition temperatures depending on the nature of betulin and alkene segments. To evaluate the antimicrobial potential of betulin-containing polymers, the fabrication of polyolefin fibrous mats (ca. 400 nm diameter) via the electrospinning technique was successfully achieved. Their morphology and hydrophobicity were studied by scanning electron microscopy (SEM) and water contact angle analyses. The fibrous mats possessed broad-spectrum antibacterial property, providing a feasible strategy to design betulin-based polymeric fibers for many applications in the biomedical field.

Betulin ameliorates 7,12-dimethylbenz(a)anthracene-induced rat mammary cancer by modulating MAPK and AhR/Nrf-2 signaling pathway

The aim of the present study is to explore the preventive efficacy of betulin (BE) in 7,12-dimethylbenz(a)anthracene (DMBA)-administered mammary cancer by modulating Ahr/Nrf2 signaling in experimental models. The mammary cancer was stimulated by the addition of DMBA (25 mg/kg/b.Wt) mixed in 1 ml of vehicle solution (sunflower oil and saline 1:1) through subcutaneous injection. The DMBA-exposed mammary tumor models showed low bodyweight, elevated quantities of lipid peroxidation molecules (TBARS and LOOH), and low enzymatic (GPx, SOD, and CAT), and nonenzymatic (GSH, vitamin C, and vitamin E) antioxidant activities in plasma and mammary tissues. Moreover, histopathological studies confirmed that invasive ductal carcinoma was observed in DMBA-induced mammary tissue of the experimental model. Dietary oral supplementation of BE prevents the loss of bodyweight, overproduces lipid peroxidation, and restores the antioxidant activities in DMBA-exposed experimental animals. The nuclear factor erythroid 2-related factor 2 (Nrf2) is a crucial antioxidant protein that involves preventing numerous cancers. Therefore, Nrf2-associated signaling concern is a significant target for preventing mammary cancer. This study observed an increased expression of MAPKs, Keap1, ARNT, AhR, and CYP1A1, whereas decreased expression of HO-1 and Nrf2 in DMBA-induced cancer-bearing experimental animals. The oral supplementation of BE effectively modulates the expression of MAPKs, AhR/Nrf2-associated protein expressions in DMBA-exposed experimental animals. This current study concluded that BE is a strong antioxidant, which triggers the MAPKs-mediated oxidative stress and inhibits proliferative markers by restoring the activity of Nrf2 signaling.

Effect of Different Pretreatment Methods on Birch Outer Bark: New Biorefinery Routes

A comparative study among different pretreatment methods used for the fractionation of the birch outer bark components, including steam explosion, hydrothermal and organosolv treatments based on the use of ethanol/water media, is reported. The residual solid fractions have been characterized by ATR-FTIR, ¹³C-solid-state NMR and morphological alterations after pretreatment were detected by scanning electron microscopy. The general chemical composition of the untreated and treated bark including determination of extractives, suberin, lignin and monosaccharides was also studied. Composition of the residual solid fraction and relative proportions of different components, as a function of the processing conditions, could be established. Organosolv treatment produces a suberin-rich solid fraction, while during hydrothermal and steam explosion treatment cleavage of polysaccharide bonds occurs. This work will provide a deeper fundamental knowledge of the bark chemical composition, thus increasing the utilization efficiency of birch outer bark and may create possibilities to up-scale the fractionation processes.

Birch bark extract as therapy for chronic hepatitis C--a pilot study

The hepatoprotective effect of birch bark extract (BBE) in patients with chronic hepatitis C (CHC) was studied. Forty-two patients with serologically confirmed chronic hepatitis C were treated for 12 weeks with 160 mg standardized BBE per day. The primary outcome parameter measured was the rate of alanine aminotransferase (ALT) normalization after 12 weeks. Secondary parameters included the course of ALT, aspartate aminotransferase (AST) levels, quantitative HCV RNA levels, subjective symptoms associated with CHC (fatigue, abdominal discomfort, depression, and dyspepsia), safety and compliance. The qualitative-quantitative analysis of BBE was made using high performance liquid chromatography to confirm the presence of 75% betulin and 3.5% betulinic acid. Significant differences in the mean ALT and HCV RNA levels were observed after 12 weeks of treatment. The level of ALT was decreased in 54.0% and normalized (p=0.046). HCV RNA was reduced in 43.2% (p=0.016). After 12 weeks of treatment, reports of fatigue and abdominal discomfort were reduced by 6-fold (p=0.028) and 3-fold (p=0.05), respectively. Dyspepsia was no longer reported (p=0.042) and the effect was significantly different from baseline. Because this study lacks a control group clinical relevance of the data can only be estimated in future by following controlled clinical trials.