A design of new nanocomposites of bacterial cellulose (BC) and betulin diphosphate (BDP) pre-impregnated into the surface of zinc oxide nanoparticles (ZnO NPs) for the production of wound dressings is proposed. The sizes of crystalline BC and ZnO NPs (5–25%) corresponded to 5–6 nm and 10–18 nm, respectively (powder X-ray diffractometry (PXRD), Fourier-infrared (FTIR), ultraviolet (UV), atomic absorption (AAS) and photoluminescence (PL) spectroscopies). The biological activity of the wound dressings “BC-ZnO NPs-BDP” was investigated in rats using a burn wound model. Morpho-histological studies have shown that more intensive healing was observed during treatment with hydrophilic nanocomposites than the oleophilic standard (ZnO NPs-BDP oleogel; p < 0.001). Treatment by both hydrophilic and lipophilic agents led to increases in antioxidant enzyme activity (superoxide dismutase (SOD), catalase) in erythrocytes and decreases in the malondialdehyde (MDA) concentration by 7, 10 and 21 days (p < 0.001). The microcirculation index was restored on the 3rd day after burn under treatment with BC-ZnO NPs-BDP wound dressings. The results of effective wound healing with BC-ZnO NPs-BDP nanocomposites can be explained by the synergistic effect of all nanocomposite components, which regulate oxygenation and microcirculation, reducing hypoxia and oxidative stress in a burn wound.

The room temperature oxidation of betulin by Cr(VI) compounds in aqueous acetone on solid supports such as alumina, zeolites and silica gel has been studied. The oxidation on alumina support leaded to a single product—betulonic acid—in quantitative yield. One hundred percent selective oxidation during 30 min of betulin up to betulonic aldehyde was determined when silica gel support was used. The oxidation of betulin using zeolites as a support gives a mixture of betulonic acid and aldehyde in a 2:1 ratio. It is proposed the selective oxidation up to betulonic acid is due to the influence of Al³⁺-ions.

A soft synthesis of nanoceria with non-stoichiometric composition (33% Ce³⁺/67% Ce⁴⁺) named CeO₂ NPs in bacterial cellulose (BC) matrix in the form of aerogel and hydrogel with controlled CeO₂ NPs content was proposed. The advantage of CeO₂ NPs synthesis in BC is the use of systemic antacid API–trisamine as a precursor, which did not destruct cellulose at room temperature and enabled a reduction in the duration of synthesis and the number of washes. Moreover, this method resulted in the subsequent uniform distribution of CeO₂ NPs in the BC matrix due to cerium (III) nitrate sorption in the BC matrix. CeO₂ NPs (0.1–50.0%) in the BC matrix had a fluorite structure with a size of 3–5 nm; the specific surface area of the composites was 233.728 m²/g. CeO₂ NPs in the BC-CeO₂ NPs composite demonstrated SOD-like activity in the processes of oxidation and reduction of cytochrome c (cyt c³⁺/cyt c²⁺), as well as epinephrine to inhibit its auto-oxidation in aqueous solutions by 33–63% relative to the control. In vitro experiments on rat blood showed a decrease in the MDA level and an increase in the activity of antioxidant defense enzymes–SOD by 24% and G6PDH by 2.0–2.5 times. Therefore, BC-CeO₂ NPs can be proposed for wound healing as antioxidant material.

We studied oleogels containing zinc oxide nanoparticles (ZnO NPs) and lupane triterpenoids in sunflower oil for the treatment of burns. The modification of ZnO was carried out by treatment with alcohol solutions of betulin, betulonic acid, betulin diacetate and betulin diphosphate. The properties of modified ZnO NPs were studied by powder XRD (average sizes of 10–20 nm), FTIR (νZnO 450 cm⁻¹), UV–vis (345–360 nm), and blue–violet emission (380–420 nm). The identification and assay of modified ZnO NPs and triterpenoids were estimated. The treatment by oleogels of deep II-degree burns was studied on rats using histological studies, Doppler flowmetry and evaluation of enzymes activity and malonic dialdehyde (MDA) level. After the action of oleogels, burn wound area, and the necrosis decreased twice on the 10th day in comparison with the 1st day after burn. The microcirculation index in the near-wound zone by 20–30% improved compared with the group without treatment. Evaluation of the enzyme activity and the MDA level after treatment by oleogels during the course of 10 days showed them returning to normal. The improvement of antioxidant biochemical indexes, as well as wounds’ healing, was mainly determined by the influence of zinc oxide nanoparticles.

Zinc oxide nanoparticles (ZnO NPs) modified by oxopyrymidine alcohol, also known as xymedone (Xym), were obtained and studied using FTIR, UV-vis, and fluorescent spectroscopy, and SEM, BET, powder XRD, and DLS analysis. A formulation of thixotropic hydrophilic gels containing Carbopol-based Xym and ZnO NPs was developed. A vertical Franz cell with a cellulose acetate membrane was used as a model to investigate the passive diffusion of the gel components by AAS. The gel components—Xym and ZnO NPs—were shown to penetrate through acetyl cellulose membrane within 5–7 h depending on an initial amount, and its values were in the range of 56–77%. The penetration of modified ZnO NPs by Xym was more effective in contrast to ZnO NPs without modification. The burn wound healing activity of ZnO NPs–Xym gel was demonstrated on a thermal burn wound model on rats. SOD and GR activity was increased by 30–35% during ZnO NPs–Xym gel treatment, the burn area on 10 postburn day decreased by 10% in contrast to a positive control, Methyluracyl^®® ointment.

In the review the biological properties (antitumor, antiviral, hypolipidemic, anti-inflammatory, etc.) and bioavailability of betulin and betulinic acid derivatives were discussed. These compounds are isolated from various natural sources, including birch bark (Betula, Betulaceae). The structure-activity correlation was considered for well-known betulinic acid derivatives. The perspectivity of this compounds as active pharmaceutical ingredients was demonstrated by in vitro, in vivo, and ex vivo experiments. The type of antitumor actions, generally, depends on substituents at the C-3 and C-28 carbon atoms of the lupane skeleton. It is very important that the carboxyl group of betulinic acid in the C-28 position was present. In this case, the cytotoxicity of C-3 modified derivatives is extremely high for all tested cell lines. The use of these compounds in the medical practice is complicated because they have low bioavailability and poor water solubility (from 1 to 100 µg*l-1). The main chemical syntheses for solubility improvement of betulin derivatives by grafting of hydrophilic groups were discussed. Moreover, the colloid-chemical approaches for the bioavailability improving of triterpenoids include: 1) including of these compounds in liposomes, vesicles and other nanoparticles; 2) obtaining of micelles with high-molecular compounds; 3) colloid-chemical dissolution due to physico-mechanical action; 4) inclusion complexes formation; 5) using of polymers for triterpenoids grafting. Chemical modification of betulin and betulinic acid by polar groups, such as phosphate/phosphonate, sulfate, amino acids, etc. has been shown for bioavailability improving.