Tetracyclic and Pentacyclic Triterpenes with High Therapeutic Efficiency in Wound Healing Approaches

Transplanted artificial amnion membrane enhanced wound healing in third-degree burn injury diabetic mouse model

Introduction

Wound healing is severely compromised in patients with diabetes owing to factors such poor blood circulation, delayed immune response, elevated blood sugar levels, and neuropathy. Although the development of new wound healing products and prevention of serious complications such as infections in wounds have received substantial interest, wound healing remains a challenge in regenerative medicine. Burn wounds, especially third-degree burns, are difficult to treat because they are associated with immune and inflammatory reactions and distributive shock. Wound care and treatment that protects the burn site from infection and allows wound healing can be achieved with bioengineered wound dressings. However, few studies have reported effective dressings for third-degree burn wounds, making it important to develop new dressing materials.

Methods

In this study, we developed an artificial amniotic membrane (AM) using epithelial and mesenchymal cells derived from human amnion as a novel dressing material. The artificial AM was applied to the wound of a diabetic third-degree burn model and its wound healing ability was evaluated.

Results

This artificial amnion produced multiple growth factors associated with angiogenesis, fibroblast proliferation, and anti-inflammation. In addition, angiogenesis and granulation tissue formation were promoted in the artificial AM-treated mouse group compared with the control group. Furthermore, the inflammatory phase was prolonged in the control group.

Conclusions

Our preliminary results indicate that the artificial AM might be useful as a new dressing for refractory ulcers and third-degree burns. This artificial AM-based material represents great potential for downstream clinical research and treatment of diabetes patients with third-degree burns.

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.

Challenges and Prospects of Development of Herbal Biomaterial Based Ethical Wound Care Products-A Scoping Review

Total wound care is an unmet therapeutic need considering the morbidity and mortality associated with the rising prevalence of nonhealing/chronic wounds. Current wound management fails to address all aspects/types of wounds despite the availability of scores of traditional and modern, investigational products. Traditional medicine drugs of wound healing repute validated to target multiple biological pathways and key events in the mammalian wound healing cascade, reportedly affecting wound healing phases. Advances in the development of biocomposite matrices and their analytical characterization warrant a relook at consolidating time-tested wound healing properties of herbal bioactives for prospective development as ethical wound care products. Aside from the bottlenecks of their multiconstituent profiling and clinical trial data generation, regulatory hurdles also cloister any systematic attempts at their re-engineering into clinical deliverables. In the context of national policy changes to bring in totally indigenous solutions, countries with a huge knowledge/material resource on wound healing bioactives need to essentially facilitate the same.

Bioactive triterpenoid compounds of Poria cocos (Schw.) Wolf in the treatment of diabetic ulcers via regulating the PI3K-AKT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic ulcers represent a chronic condition characterized by prolonged hyperglycemia and delayed wound healing, accompanied by endocrine disorders, inflammatory responses, and microvascular damage in the epidermal tissue, demanding effective clinical treatment approaches. For thousands of years, ancient Chinese ethnopharmacological studies have documented the use of Poria cocos (Schw.) Wolf in treating diabetic ulcers. Recent research has substantiated the diverse pharmacological effects of Poria cocos (Schw.) Wolf, including its potential to alleviate hyperglycemia and exhibit anti-inflammatory, antioxidant, and immune regulatory properties, which could effectively mitigate diabetic ulcer symptoms. Furthermore, being a natural medicine, Poria cocos (Schw.) Wolf has demonstrated promising therapeutic effects and safety in the management of diabetic ulcers, holding significant clinical value. Despite its potential clinical efficacy and applications in diabetic ulcer treatment, the primary active components and underlying pharmacological mechanisms of Poria cocos (Schw.) Wolf remains unclear. Further investigations are imperative to establish a solid foundation for drug development in this domain.

AIM OF THE STUDY AND MATERIALS AND METHODS

In this study, we aimed to identify the active compounds and potential targets of Poria cocos (Schw.) Wolf using UHPLC-Q-TOF-MS and TCMSP databases. Additionally, we attempt to identify targets related to diabetic ulcers. Following enrichment analysis, a network of protein-protein interactions was constructed to identify hub genes based on the common elements between the two datasets. To gain insights into the binding activities of the hub genes and active ingredients, molecular docking analysis was employed. Furthermore, to further validate the therapeutic effect of Poria cocos (Schw.) Wolf, we exerted in vitro experiments using human umbilical vein vascular endothelial cells and human myeloid leukemia monocytes (THP-1). The active ingredient of Poria cocos (Schw.) Wolf was applied in these experiments. Our investigations included various assays, such as CCK-8, scratch test, immunofluorescence, western blotting, RT-PCR, and flow cytometry, to explore the potential of Poria cocos (Schw.) Wolf triterpenoid extract (PTE) in treating diabetic ulcers.

RESULTS

The findings here highlighted PTE as the primary active ingredient in Poria cocos (Schw.) Wolf. Utilizing network pharmacology, we identified 74 potential targets associated with diabetic ulcer treatment for Poria cocos (Schw.) Wolf, with five hub genes (JUN, MAPK1, STAT3, AKT1, and CTNNB1). Enrichment analysis revealed the involvement of multiple pathways in the therapeutic process, with the PI3K-AKT signaling pathway showing significant enrichment. Through molecular docking, we discovered that relevant targets within this pathway exhibited strong binding with the active components of Poria cocos (Schw.) Wolf. In vitro experiments unveiled that PTE (10 mg/L) facilitated the migration of human umbilical vein vascular endothelial cells (P < 0.05). PTE also increased the expression of CD31 and VEGF mRNA (P < 0.05) while activating the expressions of p-PI3K and p-AKT (P < 0.05). Moreover, PTE demonstrated its potential by reducing the expression of IL-1β, IL-6, TNF-α, and NF-κB mRNA in THP-1 (P < 0.05) and fostering M2 macrophage polarization. These results signify the potential therapeutic effects of PTE in treating diabetic ulcers, with its beneficial actions mediated through the PI3K-AKT signaling pathway.

CONCLUSIONS

PTE is the main active ingredient in Poria cocos (Schw.) Wolf that exerts therapeutic effects. Through PI3K-AKT signaling pathway activation and inflammatory response reduction, PTE promotes angiogenesis, thereby healing diabetic ulcers.

Electrospun nanofibers synthesized from polymers incorporated with bioactive compounds for wound healing

The development of innovative wound dressing materials is crucial for effective wound care. It's an active area of research driven by a better understanding of chronic wound pathogenesis. Addressing wound care properly is a clinical challenge, but there is a growing demand for advancements in this field. The synergy of medicinal plants and nanotechnology offers a promising approach to expedite the healing process for both acute and chronic wounds by facilitating the appropriate progression through various healing phases. Metal nanoparticles play an increasingly pivotal role in promoting efficient wound healing and preventing secondary bacterial infections. Their small size and high surface area facilitate enhanced biological interaction and penetration at the wound site. Specifically designed for topical drug delivery, these nanoparticles enable the sustained release of therapeutic molecules, such as growth factors and antibiotics. This targeted approach ensures optimal cell-to-cell interactions, proliferation, and vascularization, fostering effective and controlled wound healing. Nanoscale scaffolds have significant attention due to their attractive properties, including delivery capacity, high porosity and high surface area. They mimic the Extracellular matrix (ECM) and hence biocompatible. In response to the alarming rise of antibiotic-resistant, biohybrid nanofibrous wound dressings are gradually replacing conventional antibiotic delivery systems. This emerging class of wound dressings comprises biopolymeric nanofibers with inherent antibacterial properties, nature-derived compounds, and biofunctional agents. Nanotechnology, diminutive nanomaterials, nanoscaffolds, nanofibers, and biomaterials are harnessed for targeted drug delivery aimed at wound healing. This review article discusses the effects of nanofibrous scaffolds loaded with nanoparticles on wound healing, including biological (in vivo and in vitro) and mechanical outcomes.

A Preliminary Report Regarding the Morphological Changes of Nano-Enabled Pharmaceutical Formulation on Human Lung Carcinoma Monolayer and 3D Bronchial Microtissue

Background and Objectives: Nowadays, the development of enabled pharmaceutical nanoparticles of solid lipid type is continuously growing, because they have the potential to be used for targeted drug release leading to an increased effect of chemotherapy, being used in lung cancer nano-diagnosis and nano-therapy. The current study reports the preliminary results obtained regarding the biological effect of a new nano-enabled pharmaceutical formulation in terms of its cytotoxic and biosafety profile. Materials and Methods: The pharmaceutical formulations consist of solid lipid nanoparticles (SLN) obtained via the emulsification-diffusion method by loading green iron oxide nanoparticles (green-IONPs) with a pentacyclic triterpene (oleanolic acid-OA). Further, a complex biological assessment was performed, employing three-dimensional (3D) bronchial microtissues (EpiAirwayTM) to determine the biosafety profile of the SLN samples. The cytotoxic potential of the samples was evaluated on human lung carcinoma, using an in vitro model (A549 human lung carcinoma monolayer). Results: The data revealed that the A549 cell line was strongly affected after treatment with SLN samples, especially those that contained OA-loaded green-IONPs obtained with Ocimum basilicum extract (under 30% viability rates). The biosafety profile investigation of the 3D normal in vitro bronchial model showed that all the SLN samples negatively affected the viability of the bronchial microtissues (below 50%). As regards the morphological changes, all the samples induce major changes such as loss of the surface epithelium integrity, loss of epithelial junctions, loss of cilia, hyperkeratosis, and cell death caused by apoptosis. Conclusions: In summary, the culprit for the negative impact on viability and morphology of 3D normal bronchial microtissues could be the too-high dose (500 µg/mL) of the SLN sample used. Nevertheless, further adjustments in the SLN synthesis process and another complex in vitro evaluation will be considered for future research.

Metallic elements combine with herbal compounds upload in microneedles to promote wound healing: a review

Wound healing is a dynamic and complex restorative process, and traditional dressings reduce their therapeutic effectiveness due to the accumulation of drugs in the cuticle. As a novel drug delivery system, microneedles (MNs) can overcome the defect and deliver drugs to the deeper layers of the skin. As the core of the microneedle system, loaded drugs exert a significant influence on the therapeutic efficacy of MNs. Metallic elements and herbal compounds have been widely used in wound treatment for their ability to accelerate the healing process. Metallic elements primarily serve as antimicrobial agents and facilitate the enhancement of cell proliferation. Whereas various herbal compounds act on different targets in the inflammatory, proliferative, and remodeling phases of wound healing. The interaction between the two drugs forms nanoparticles (NPs) and metal-organic frameworks (MOFs), reducing the toxicity of the metallic elements and increasing the therapeutic effect. This article summarizes recent trends in the development of MNs made of metallic elements and herbal compounds for wound healing, describes their advantages in wound treatment, and provides a reference for the development of future MNs.

Current Advances in Stimuli-Responsive Hydrogels as Smart Drug Delivery Carriers

In recent years, significant advancements in the field of advanced materials and hydrogel engineering have enabled the design and fabrication of smart hydrogels and nanogels that exhibit sensitivity to specific signals or pathological conditions, leading to a wide range of applications in drug delivery and disease treatment. This comprehensive review aims to provide an in-depth analysis of the stimuli-responsive principles exhibited by smart hydrogels in response to various triggers, such as pH levels, temperature fluctuations, light exposure, redox conditions, or the presence of specific biomolecules. The functionality and performance characteristics of these hydrogels are highly influenced by both their constituent components and fabrication processes. Key design principles, their applications in disease treatments, challenges, and future prospects were also discussed. Overall, this review aims to contribute to the current understanding of gel-based drug delivery systems and stimulate further research in this rapidly evolving field.

Oleanolic Acid Complexation with Cyclodextrins Improves Its Cell Bio-Availability and Biological Activities for Cell Migration

Wound healing is a complex process to restore skin. Plant-derived bioactive compounds might be a source of substances for the treatment of wounds stalled in a non-resolving stage of wound healing. Oleanolic acid (OA), a pentacyclic triterpene, has shown favorable wound healing properties both in vitro and in vivo. Unfortunately, OA cannot be solubilized in aqueous media, and it needs to be helped by the use of dimethyl sulfoxide (DMSO). In this paper, we have shown that cyclodextrins (CDs) are a good alternative to DMSO as agents to deliver OA to cells, providing better features than DMSO. Cyclodextrins are natural macromolecules that show a unique tridimensional structure that can encapsulate a wide variety of hydrophobic compounds. We have studied the cyclodextrin-encapsulated form of OA with OA/DMSO, comparing their stability, biological properties for cell migration, and cell viability. In addition, detailed parameters related to cell migration and cytoskeletal reorganization have been measured and compared. Our results show that OA-encapsulateds compound exhibit several advantages when compared to non-encapsulated OA in terms of chemical stability, migration enhancement, and preservation of cell viability.

Asymmetric Total Syntheses of Euphol and Tirucallol

Asymmetric de novo syntheses of euphol and tirucallol have been accomplished by way of a concise sequence of chemical steps featuring several modern stereoselective transformations. The preparative solution described for these complex problems in natural product synthesis departs significantly from biomimetic polyene cyclization chemistry, which has been leveraged to address related tetracyclic triterpenoid targets. In particular, a diastereoselective Friedel-Crafts-type cyclization was employed to establish a tetracycle bearing a stereodefined quaternary center at C9 (steroid numbering) that provided access to intermediates of relevance for introducing the C10 and C14 quaternary centers by sequential stereospecific 1,2-alkyl shifts (C9 → C10 and C15 → C14). Finally, the stereodefined C17 side chain was introduced in a single step by late-stage stereoselective conjugate addition to an intermediate possessing a D-ring enone. Notably, these de novo asymmetric syntheses are the first of their kind, providing completely synthetic access to enantiodefined euphane and tirucallane systems. Overall, each synthesis has been accomplished in fewer than 20 linear chemical steps from a simple Hajos-Parrish-derived ketone through a sequence that features just 15 chromatographic operations.

Therapeutic Candidates for Alzheimer's Disease: Saponins

Drug development for Alzheimer's disease, the leading cause of dementia, has been a long-standing challenge. Saponins, which are steroid or triterpenoid glycosides with various pharmacological activities, have displayed therapeutic potential in treating Alzheimer's disease. In a comprehensive review of the literature from May 2007 to May 2023, we identified 63 references involving 40 different types of saponins that have been studied for their effects on Alzheimer's disease. These studies suggest that saponins have the potential to ameliorate Alzheimer's disease by reducing amyloid beta peptide deposition, inhibiting tau phosphorylation, modulating oxidative stress, reducing inflammation, and antiapoptosis. Most intriguingly, ginsenoside Rg1 and pseudoginsenoside-F11 possess these important pharmacological properties and show the best promise for the treatment of Alzheimer's disease. This review provides a summary and classification of common saponins that have been studied for their therapeutic potential in Alzheimer's disease, showcasing their underlying mechanisms. This highlights the promising potential of saponins for the treatment of Alzheimer's disease.

Comparison of In Vitro Antimelanoma and Antimicrobial Activity of 2,3-Indolo-betulinic Acid and Its Glycine Conjugates

Malignant melanoma is one of the most pressing problems in the developing world. New therapeutic agents that might be effective in treating malignancies that have developed resistance to conventional medications are urgently required. Semisynthesis is an essential method for improving the biological activity and the therapeutic efficacy of natural product precursors. Semisynthetic derivatives of natural compounds are valuable sources of new drug candidates with a variety of pharmacological actions, including anticancer ones. Two novel semisynthetic derivatives of betulinic acid-N-(2,3-indolo-betulinoyl)diglycylglycine (BA1) and N-(2,3-indolo-betulinoyl)glycylglycine (BA2)-were designed and their antiproliferative, cytotoxic, and anti-migratory activity against A375 human melanoma cells was determined in comparison with known N-(2,3-indolo-betulinoyl)glycine (BA3), 2,3-indolo-betulinic acid (BA4) and naturally occurring betulinic acid (BI). A dose-dependent antiproliferative effect with IC₅₀ values that ranged from 5.7 to 19.6 µM was observed in the series of all five compounds including betulinic acid. The novel compounds BA1 (IC₅₀ = 5.7 µM) and BA2 (IC₅₀ = 10.0 µM) were three times and two times more active than the parent cyclic structure B4 and natural BI. Additionally, compounds BA2, BA3, and BA4 possess antibacterial activity against Streptococcus pyogenes ATCC 19615 and Staphylococcus aureus ATCC 25923 with MIC values in the range of 13-16 µg/mL and 26-32 µg/mL, respectively. On the other hand, antifungal activity toward Candida albicans ATCC 10231 and Candida parapsilosis ATCC 22019 was found for compound BA3 with MIC 29 µg/mL. This is the first report of antibacterial and antifungal activity of 2,3-indolo-betulinic acid derivatives and also the first extended report on their anti-melanoma activity, which among others includes data on anti-migratory activity and shows the significance of amino acid side chain on the observed activity. The obtained data justify further research on the anti-melanoma and antimicrobial activity of 2,3-indolo-betulinic acid derivatives.

Facile preparation of a novel nanoemulsion based hyaluronic acid hydrogel loading with Poria cocos triterpenoids extract for wound dressing

Diabetic wounds have been a serious concern for human health owing to their long chronic inflammation and reduced vascularization. Herein, we report novel oil-in-water (o/w) nanoemulsions (NEs) containing Poria cocos triterpenes extract (PTE) to fabricate hyaluronic acid hydrogels (PTE-NEs) for the treatment of diabetic wounds. The size and morphology of NEs are analyzed by transmission electron microscope (TEM) and Zeta potential, respectively. Furthermore, the rheological behavior and morphology of synthesized hydrogels are also determined. It is found that PTE-NEs gel has a homogeneous and porous structure with good elastic properties. In addition, in vitro experiments show that the cell viability of PTE-NEs gel is >85 % without cytotoxicity. In vivo experiments of diabetic rats demonstrate that the PTE-NEs gel can not only significantly accelerate diabetic wound healing, collagen deposition, M2 macrophage polarization, and angiogenesis, but also inhibit inflammation. In conclusion, PTE plays a significant role in wound healing and exhibits anti-inflammatory effects, demonstrating its great potential in treating diabetic wounds.

Antibacterial Mode of Action of β-Amyrin Promotes Apoptosis-Like Death in Escherichia coli by Producing Reactive Oxygen Species

β-Amyrin is a pentacyclic triterpene widely distributed in leaves and stems worldwide. The ability of β-amyrin to induce the production of reactive oxygen species (ROS) in microorganisms suggests its potential as an antimicrobial agent. Thus, this study aimed to elucidate the antibacterial mode of action of β-amyrin. We treated Escherichia coli cells with β-amyrin and found that it triggered ROS accumulation. Excessive stress caused by ROS, particularly hydroxyl radicals, induces glutathione (GSH) dysfunction. GSH protects cells from oxidative and osmotic stresses; thus, its dysfunction leads to membrane depolarization. The resultant change in membrane potential leads to the release of apoptotic proteins, such as caspases. The activated caspases-like protein promotes the cleavage of DNA into single strands, which is a hallmark of apoptosis-like death in bacteria. Apoptotic cells usually undergo events such as DNA fragmentation and phosphatidylserine exposure, differentiating them from necrotic cells, and the cells treated with β-amyrin in this study were positive for annexin V and negative for propidium iodide, indicating apoptosis-like death. In conclusion, our findings suggest that the antibacterial mode of action of β-amyrin involves the induction of ROS, which resulted in apoptosis-like death in E. coli.

Microbial Natural Products with Wound-Healing Properties

Wound healing continues to pose a challenge in clinical settings. Moreover, wound management must be performed properly and efficiently. Acute wound healing involves multiple cell divisions, a new extracellular matrix, and the process of formation, such as growth factors and cytokines, which are released at the site of the wound to regulate the process. Any changes that disrupt the healing process could cause tissue damage and prolong the healing process. Various factors, such as microbial infection, oxidation, and inflammation, can delay wound healing. In order to counter these problems, utilizing natural products with wound-healing effects has been reported to promote this process. Several natural products have been associated with wound healing, most of which are from medicinal plants. However, secondary microbial metabolites have not been extensively studied for their wound-healing properties. Further, investigations on the wound-healing control of natural microbial products are required due to a lack of studies. This review discussed the in vivo and in vitro research on the wound healing activities of natural microbial products, which may assist in the development of better wound treatments in the future.

Synthesis, Anti-Influenza H1N1 and Anti-Dengue Activity of A-Ring Modified Oleanonic Acid Polyamine Derivatives

A series of sixteen A-ring modified (2,3-indolo-, 2-benzylidene) oleanonic acid derivatives, holding some cyclic amines, linear polyamines and benzylaminocarboxamides at C28, has been synthesized and screened for antiviral activity against influenza A/PuertoRico/8/34 (H1N1) and Dengue virus serotypes of DENV-1, -2, -3, -4. It was found that 28-homopiperazine 2 and 3-N-phthalyl 22 amides of oleanonic acid demonstrated high potency with selectivity index SI 27 (IC₅₀ 21 μM) and 42 (IC₅₀ 12 μM). Oleanonic acid aminoethylpiperazine amide 6 and C-azepano-erythrodiol 23 appeared to be the most effective compounds against DENV-1 (IC_50's 67 and 107 μM) and -2 (IC_50's 86 and 68 μM correspondingly) serotypes.

Biotechnological Intervention and Secondary Metabolite Production in Centella asiatica L

Centella asiatica L., commonly known as Gotu kola, Indian pennywort, and Asiatic pennyworts, is an herbaceous perennial plant that belongs to the family Apiaceae and has long been used in the traditional medicine system. The plant is known to produce a wide range of active metabolites such as triterpenoids including asiatic acid, asiaticoside, brahmoside, and madecassic acid along with other constituents including centellose, centelloside, and madecassoside, etc., which show immense pharmacological activity. Due to its beneficial role in neuroprotection activity, the plant has been considered as a brain tonic. However, limited cultivation, poor seed viability with low germination rate, and overexploitation for decades have led to severe depletion and threatened its wild stocks. The present review aimed to provide up-to-date information on biotechnological tools applied to this endangered medicinal plant for its in vitro propagation, direct or indirect regeneration, synthetic seed production, strategies for secondary metabolite productions including different elicitors. In addition, a proposed mechanism for the biosynthesis of triterpenoids is also discussed.

Structural Investigation of Betulinic Acid Plasma Metabolites by Tandem Mass Spectrometry

Betulinic acid (BA) has been extensively studied in recent years mainly for its antiproliferative and antitumor effect in various types of cancers. Limited data are available regarding the pharmacokinetic profile of BA, particularly its metabolic transformation in vivo. In this study, we present the screening and structural investigations by ESI Orbitrap MS in the negative ion mode and CID MS/MS of phase I and phase II metabolites detected in mouse plasma after the intraperitoneal administration of a nanoemulsion containing BA in SKH 1 female mice. Obtained results indicate that the main phase I metabolic reactions that BA undergoes are monohydroxylation, dihydroxylation, oxidation and hydrogenation, while phase II reactions involved sulfation, glucuronidation and methylation. The fragmentation pathway for BA and its plasma metabolites were elucidated by sequencing of the precursor ions by CID MS MS experiments.

Semisynthetic Derivatives of Pentacyclic Triterpenes Bearing Heterocyclic Moieties with Therapeutic Potential

Medicinal plants have been used by humans since ancient times for the treatment of various diseases and currently represent the main source of a variety of phytocompounds, such as triterpenes. Pentacyclic triterpenes have been subjected to numerous studies that have revealed various biological activities, such as anticancer, antidiabetic, anti-inflammatory, antimicrobial, and hepatoprotective effects, which can be employed in therapy. However, due to their high lipophilicity, which is considered to exert a significant influence on their bioavailability, their current use is limited. A frequent approach employed to overcome this obstacle is the chemical derivatization of the core structure with different types of moieties including heterocycles, which are considered key elements in medicinal chemistry. The present review aims to summarize the literature published in the last 10 years regarding the derivatives of pentacyclic triterpenes bearing heterocyclic moieties and focuses on the biologically active derivatives as well as their structure-activity relationships. Predominantly, the targeted positions for the derivatization of the triterpene skeleton are C-3 (hydroxyl/oxo group), C-28 (hydroxyl/carboxyl group), and C-30 (allylic group) or the extension of the main scaffold by fusing various heterocycles with the A-ring of the phytocompound. In addition, numerous derivatives also contain linker moieties that connect the triterpenic scaffold with heterocycles; one such linker, the triazole moiety, stands out as a key pharmacophore for its biological effect. All these studies support the hypothesis that triterpenoid conjugates with heterocyclic moieties may represent promising candidates for future clinical trials.

Does Secondary Plant Metabolite Ursolic Acid Exhibit Antibacterial Activity against Uropathogenic Escherichia coli Living in Single- and Multispecies Biofilms?

Multispecies bacterial biofilms are the often cause of chronic recurrent urinary tract infections within the human population. Eradicating such a complex bacterial consortium with standard pharmacotherapy is often unsuccessful. Therefore, plant-derived compounds are currently being researched as an alternative strategy to antibiotic therapy for preventing bacterial biofilm formation and facilitating its eradication. Therefore, our research aimed to determine the effect of secondary plant metabolite ursolic acid (UA) on the growth and survival, the quantity of exopolysaccharides formed, metabolic activity, and morphology of uropathogenic Gram-negative rods living in single- and mixed-species biofilms at various stages of their development. Spectrophotometric methods were used for biofilm mass formation and metabolic activity determination. The survival of bacteria was established using the serial dilution assay. The decrease in survival and inhibition of biofilm creation, both single- and multispecies, as well as changes in the morphology of bacterial cells were noticed. As UA exhibited better activity against young biofilms, the use of UA-containing formulations, especially during the initial steps of urinary tract infection, seems to be reasonable. However, the future direction should be a thorough understanding of the mechanisms of UA activity as a bioactive substance.

Recent Advances Regarding the Molecular Mechanisms of Triterpenic Acids: A Review (Part I)

Triterpenic acids are phytocompounds with a widespread range of biological activities that have been the subject of numerous in vitro and in vivo studies. However, their underlying mechanisms of action in various pathologies are not completely elucidated. The current review aims to summarize the most recent literature, published in the last five years, regarding the mechanism of action of three triterpenic acids (asiatic acid, oleanolic acid, and ursolic acid), corelated with different biological activities such as anticancer, anti-inflammatory, antidiabetic, cardioprotective, neuroprotective, hepatoprotective, and antimicrobial. All three discussed compounds share several mechanisms of action, such as the targeted modulation of the PI3K/AKT, Nrf2, NF-kB, EMT, and JAK/STAT3 signaling pathways, while other mechanisms that proved to only be specific for a part of the triterpenic acids discussed, such as the modulation of Notch, Hippo, and MALAT1/miR-206/PTGS1 signaling pathway, were highlighted as well. This paper stands as the first part in our literature study on the topic, which will be followed by a second part focusing on other triterpenic acids of therapeutic value.

Modulation of Inflammation-Related Lipid Mediator Pathways by Celastrol During Human Macrophage Polarization

Background and Purpose

Celastrol (CS) is a major active ingredient of the Chinese/Asian herb Tripterygium wilfordii that is frequently used as phytomedicine to treat inflammation and autoimmune diseases. We showed before that short-term exposure to CS (1 µM) favorably impacts the biosynthesis of inflammation-related lipid mediators (LM) in human polarized macrophages by modulating the activities of different lipoxygenases (LOXs). However, whether CS regulates the expression of LOXs and other related LM-biosynthetic enzymes during macrophage polarization is unknown. Here, we investigated how CS affects LM-biosynthetic enzyme expression on the protein level and studied concomitant LM signature profiles during polarization of human monocyte-derived macrophages (MDM) towards M1- and M2-like phenotypes.

Methods and Results

We used LM metabololipidomics to study the long-term effects of CS on LM profile signatures after manipulation of human monocyte-derived macrophages (MDM) during polarization. Exposure of MDM to low concentrations of CS (ie, 0.2 µM) during polarization to an inflammatory M1 phenotype potently suppressed the formation of pro-inflammatory cyclooxygenase (COX)- and 5-LOX-derived LM, especially prostaglandin (PG)E₂. Notably, gene and enzyme expression of COX-2 and microsomal PGE₂ synthase (mPGES)-1 as well as M1 markers were strongly decreased by CS during M1-MDM polarization, along with impaired activation of nuclear factor-κB and p38 mitogen-activated protein kinase. During IL-4-induced M2 polarization, CS decreased the capacity of the resulting M2-MDM to generate pro-inflammatory COX and 5-LOX products as well but it also reduced the formation of 12/15-LOX products and specialized pro-resolving mediators, without affecting the levels of liberated fatty acid substrates.

Conclusion

Depending on the timing and concentration, CS not only favorably affects LOX activities in macrophages but also the expression of LM-biosynthetic enzymes during macrophage polarization connected to changes of inflammation-related LM which might be of relevance for potential application of CS to treat inflammatory disorders.

Wound healing, anti-inflammatory and anti-melanogenic activities of ursane-type triterpenes from Semialarium mexicanum (Miers) Mennega

ETHNO-PHARMACOLOGICAL RELEVANCE

The bark of Semialarium mexicanum commonly known as 'Cancerina' is used as an infusion in Central America and Mexico to treat various wound infections, as well as skin and vaginal ulcers.

AIM OF THE STUDY

This study aimed to determine the wound healing, anti-inflammatory and anti-melanogenic activities of the aqueous extract of Semialarium mexicanum and to identify the compounds related to these activities.

MATERIALS AND METHODS

A bio-guided isolation of the active compounds of Semialarium mexicanum was carried out, selecting the sub-extracts and fractions depending on their wound healing, anti-inflammatory and anti-melanogenic activities in the RAW 264.7, NIH/3T3 and B16-F10 cells.

RESULTS

Three compounds were obtained and characterised by nuclear magnetic resonance and mass spectrometry. These compounds are (3β)-3-Hydroxy-urs-12-en-28-oic acid (1), (3β)-Urs-12-ene-3,28-diol (2) and (2α, 19α)-2,19-Dihydroxy-3-oxo-urs-12-en-28-oic acid (3). Regarding the anti-inflammatory activity, the three compounds inhibited the production of NF-κB and NO, however, compound 3 was the most active with IC₅₀ values of 8.15-8.19 μM and 8.94-9.14 μM, respectively, in all cell lines. The anti-melanogenic activity of these compounds was evaluated by the inhibition of tyrosinase and melanin in the B16-F10 cell line. The three compounds showed anti-melanogenic activity, however, compound 3 was the most active with an IC₅₀ of 8.03 μM for the inhibition of tyrosinase production, and an IC₅₀ of 8.53 μM for the inhibition of melanin production. Finally, concerning the wound healing activity, the three compounds presented proliferative activity in all the tested cell lines, however, compound 3 showed higher cell proliferation percentages than compounds 1 and 2 (88.89-89.60% compared to 64.92-65.71% and 71.53-71.99%, respectively).

CONCLUSION

The wound healing, anti-inflammatory and anti-melanogenic activity of the aqueous extract of Semialarium mexicanum was tested and analysed in the present study, after having isolated three ursane-type triterpenes.

Vesicular Nanocarriers for Phytocompounds in Wound Care: Preparation and Characterization

The need to develop wound healing preparations is a pressing challenge given the limitations of the current treatment and the rising prevalence of impaired healing wounds. Although herbal extracts have been used for many years to treat skin disorders, due to their wound healing, anti-inflammatory, antimicrobial, and antioxidant effects, their efficacy can be questionable because of their poor bioavailability and stability issues. Nanotechnology offers an opportunity to revolutionize wound healing therapies by including herbal compounds in nanosystems. Particularly, vesicular nanosystems exhibit beneficial properties, such as biocompatibility, targeted and sustained delivery capacity, and increased phytocompounds’ bioavailability and protection, conferring them a great potential for future applications in wound care. This review summarizes the beneficial effects of phytocompounds in wound healing and emphasizes the advantages of their entrapment in vesicular nanosystems. Different types of lipid nanocarriers are presented (liposomes, niosomes, transferosomes, ethosomes, cubosomes, and their derivates’ systems), highlighting their applications as carriers for phytocompounds in wound care, with the presentation of the state-of-art in this field. The methods of preparation, characterization, and evaluation are also described, underlining the properties that ensure good in vitro and in vivo performance. Finally, future directions of topical systems in which vesicle-bearing herbal extracts or phytocompounds can be incorporated are pointed out, as their development is emerging as a promising strategy.

Pentacyclic Triterpenoids Isolated from Celastraceae: A Focus in the 13C-NMR Data

The Celastraceae family comprises about 96 genera and more than 1.350 species, occurring mainly in tropical and subtropical regions of the world. The species of this family stand out as important plant sources of triterpenes, both in terms of abundance and structural diversity. Triterpenoids found in Celastraceae species display mainly lupane, ursane, oleanane, and friedelane skeletons, exhibiting a wide range of biological activities such as antiviral, antimicrobial, analgesic, anti-inflammatory, and cytotoxic against various tumor cell lines. This review aimed to document all triterpenes isolated from different botanical parts of species of the Celastraceae family covering 2001 to 2021. Furthermore, a compilation of their ¹³C-NMR data was carried out to help characterize compounds in future investigations. A total of 504 pentacyclic triterpenes were compiled and distinguished as 29 aromatic, 50 dimers, 103 friedelanes, 89 lupanes, 102 oleananes, 22 quinonemethides, 88 ursanes and 21 classified as others.

The Optimized Delivery of Triterpenes by Liposomal Nanoformulations: Overcoming the Challenges

The last decade has witnessed a sustained increase in the research development of modern-day chemo-therapeutics, especially for those used for high mortality rate pathologies. However, the therapeutic landscape is continuously changing as a result of the currently existing toxic side effects induced by a substantial range of drug classes. One growing research direction driven to mitigate such inconveniences has converged towards the study of natural molecules for their promising therapeutic potential. Triterpenes are one such class of compounds, intensively investigated for their therapeutic versatility. Although the pharmacological effects reported for several representatives of this class has come as a well-deserved encouragement, the pharmacokinetic profile of these molecules has turned out to be an unwelcomed disappointment. Nevertheless, the light at the end of the tunnel arrived with the development of nanotechnology, more specifically, the use of liposomes as drug delivery systems. Liposomes are easily synthesizable phospholipid-based vesicles, with highly tunable surfaces, that have the ability to transport both hydrophilic and lipophilic structures ensuring superior drug bioavailability at the action site as well as an increased selectivity. This study aims to report the results related to the development of different types of liposomes, used as targeted vectors for the delivery of various triterpenes of high pharmacological interest.

Immunomodulatory properties of triterpenes

The immune system is one of the main defence mechanisms of the human body. Inadequacy of this system or immunodeficiency results in increased risk of infections and tumours, whereas over-activation of the immune system causes allergic or autoimmune disorders. A well-balanced immune system is important for protection and for alleviation of these diseases. There is a growing interest to maintain a well-balanced immune system, especially after the Covid-19 pandemic. Many biological extracts, as well as natural products, have become popular due to their wide array of immunomodulatory effects and influence on the immune system. Triterpenes, one of the secondary metabolite groups of medicinal plants, exhibit immunomodulatory properties by various mechanisms. Different triterpenes, including components of commonly consumed plants, can promote some protection and alleviation of disease symptoms linked with immune responses and thus enhance overall well-being. This review aims to highlight the efficacy of triterpenes in light of the available literature evidence regarding the immunomodulatory properties of triterpenes. We have reviewed widely investigated immunomodulatory triterpenes; oleanolic acid, glycyrrhizin, glycyrrhetinic acid, pristimerin, ursolic acid, boswellic acid, celastrol, lupeol, betulin, betulinic acid, ganoderic acid, cucumarioside, and astragalosides which have important immunoregulatory properties. In spite of many preclinical and clinical trials were conducted on triterpenes related to their immunoregulatory actions, current studies have several limitations. Therefore, especially more clinical studies with optimal design is essential.

Lupeol acetate isolated from Chrysophyllum cainito L. fruit as a template for the synthesis of N-alkyl-arylsulfonamide derivatives and their synergistic effects with metronidazole against Trichomonas vaginalis

Pentacyclic triterpenes are found in a great variety of natural products and constitute an organic template for the development of new derivative compounds with therapeutic applications. In the present work, lupeol acetate isolated from Chrysophyllum cainito L. fruit was used as a template for the synthesis of novel N-alkyl-arylsulfonamide derivatives, and their synergistic effects with metronidazole against strains of Trichomonas vaginalis were tested. A library of 18 derivatives was synthesized. Ten compounds exhibited an IC₅₀ < 100 μM against a metronidazole-sensitive strain of T. vaginalis. Only seven of these compounds (12, 15, 18-22) also showed activity against metronidazole-resistant strains. The compounds 20 (N-cyclohexyl-p-chlorobenzenesulfonamidolupeol acetate) and 22 (N-cyclohexyl-p-nitrobenzenesulfonamidolupeol acetate) exhibited a similar IC₅₀ against both susceptible and resistant T. vaginalis strains and enhanced the efficacy of metronidazole in a partial and total synergistic way, respectively. These data provided evidence of the trichomonicidal effect of N-alkyl-arylsulfonamide derivatives of lupeol acetate, representing highly promising novel antiparasitic agents.

Amphimas pterocarpoides harms.: An Evaluation of flavonoid and phenolic contents, wound healing, anthelmintic and antioxidant activities of the leaves and stem bark

The present study evaluated the wound healing, anthelmintic and antioxidant potentials of crude methanol extracts and fractions (petroleum ether, ethyl acetate and methanol) of the leaves and stem bark of Amphimas pterocarpoides. Wound healing activity was determined by the dermal excision model in rats; anthelmintic activity was evaluated by the adult worm motility test using the adult Indian worm, Pheretima postuma. Total flavonoid, phenolic content and antioxidant activity were assessed by the aluminum chloride colorimetric, Folin Ciocalteu, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and total antioxidant capacity (TAC) assays respectively. HPLC/UV fingerprints were developed for quality control. The maximum amount of phenolics and flavonoids were detected in the methanol fractions of the stem bark (225.0 ± 20.0 mg/g gallic acid equivalent (GAE) and 201.0 ± 1.41 mg/g quercetin equivalent (QCE) respectively) and leaves (84.54 ± 1.36 mg/g GAE and 130.7 ± 1.71 mg/g QCE, respectively). Both leaf and bark displayed remarkable free radical scavenging and TAC with the highest effect given by the methanol fractions. Significant (p < 0.05) wound contraction was achieved by topical application of the leaf (APL) and stem bark (APS) ointments (5-15%) with >90 % wound surface closure for 1% silver sulphadiazine, APS 15% and APL 10% treated groups by day 15. APL and APS demonstrated a concentration- and time-dependent paralysis and mortality of the P. posthuma with APL (6.25 mg/mL) causing worm paralysis at 82.60 min and death at 93 min, better than 10 mg/mL albendazole (paralysis at 76.30 min; death at 117 min). Tannins, triterpenoids, phytosterols, flavonoids, saponins and coumarins were detected in the leaves and bark. The results have proven the potential of A. pterocarpoides as a wound healing and anthelmintic agent, giving scientific credence to its use in traditional medicine.

3-Pyridinylidene Derivatives of Chemically Modified Lupane and Ursane Triterpenes as Promising Anticancer Agents by Targeting Apoptosis

Cancer persists as a global challenge due to the extent to which conventional anticancer therapies pose high risks counterbalanced with their therapeutic benefit. Naturally occurring substances stand as an important safer alternative source for anticancer drug development. In the current study, a series of modified lupane and ursane derivatives was subjected to in vitro screening on the NCI-60 cancer cell line panel. Compounds 6 and 7 have been identified as highly active with GI₅₀ values ranging from 0.03 µM to 5.9 µM (compound 6) and 0.18–1.53 µM (compound 7). Thus, these two compounds were further assessed in detail in order to identify a possible antiproliferative mechanism of action. DAPI (4′,6-diamidino-2-phenylindole) staining revealed that both compounds induced nuclei condensation and overall cell morphological changes consistent with apoptotic cell death. rtPCR analysis showed that both compounds induced upregulation of proapoptotic Bak and Bad genes while downregulating Bcl-XL and Bcl-2 antiapoptotic genes. Molecular docking analysis revealed that both compounds exhibited high scores for Bcl-XL inhibition, while compound 7 showed higher in silico Bcl-XL inhibition potential as compared to the native inhibitor ATB-737, suggesting that compounds may induce apoptotic cell death through targeted antiapoptotic protein inhibition, as well.

Oleogel Formulations for the Topical Delivery of Betulin and Lupeol in Skin Injuries-Preparation, Physicochemical Characterization, and Pharmaco-Toxicological Evaluation

The skin integrity is essential due to its pivotal role as a biological barrier against external noxious factors. Pentacyclic triterpenes stand as valuable plant-derived natural compounds in the treatment of skin injuries due to their anti-inflammatory, antioxidant, antimicrobial, and healing properties. Consequently, the primary aim of the current investigation was the development as well as the physicochemical and pharmaco-toxicological characterization of betulin- and lupeol-based oleogels (Bet OG and Lup OG) for topical application in skin injuries. The results revealed suitable pH as well as organoleptic, rheological, and textural properties. The penetration and permeation of Bet and Lup oleogels through porcine ear skin as well as the retention of both oleogels in the skin were demonstrated through ex vivo studies. In vitro, Bet OG and Lup OG showed good biocompatibility on HaCaT human immortalized cells. Moreover, Bet OG exerted a potent wound-healing property by stimulating the migration of the HaCaT cells. The in ovo results demonstrated the non-irritative potential of the developed formulations. Additionally, the undertaken in vivo investigation indicated a positive effect of oleogels treatment on skin parameters by increasing skin hydration and decreasing erythema. In conclusion, oleogel formulations are ideal for the local delivery of betulin and lupeol in skin disorders.

Histochemical and Phytochemical Analysis of Lamium album subsp. album L. Corolla: Essential Oil, Triterpenes, and Iridoids

The aim of this study was to conduct a histochemical analysis to localize lipids, terpenes, essential oil, and iridoids in the trichomes of the L. album subsp. album corolla. Morphometric examinations of individual trichome types were performed. Light and scanning electron microscopy techniques were used to show the micromorphology and localization of lipophilic compounds and iridoids in secretory trichomes with the use of histochemical tests. Additionally, the content of essential oil and its components were determined using gas chromatography-mass spectrometry (GC-MS). Qualitative analyses of triterpenes carried out using high-performance thin-layer chromatography (HPTLC) coupled with densitometric detection, and the iridoid content expressed as aucubin was examined with spectrophotometric techniques. We showed the presence of iridoids and different lipophilic compounds in papillae and glandular and non-glandular trichomes. On average, the flowers of L. album subsp. album yielded 0.04 mL/kg of essential oil, which was dominated by aldehydes, sesquiterpenes, and alkanes. The extract of the L. album subsp. album corolla contained 1.5 × 10^-3 ± 4.3 × 10^-4 mg/mL of iridoid aucubin and three triterpenes: oleanolic acid, β-amyrin, and β-amyrin acetate. Aucubin and β-amyrin acetate were detected for the first time. We suggest the use of L. album subsp. album flowers as supplements in human nutrition.

The Presence of a Cyclohexyldiamine Moiety Confers Cytotoxicity to Pentacyclic Triterpenoids

Pentacyclic triterpenoids oleanolic acid, ursolic acid, betulinic acid, and platanic acid were acetylated and converted into several amides 9-31; the cytotoxicity of which has been determined in sulforhodamine B assays employing seral human tumor cell lines and nonmalignant fibroblasts. Thereby, a betulinic acid/trans-1,4-cyclohexyldiamine amide showed excellent cytotoxicity (for example, EC₅₀ = 0.6 μM for HT29 colon adenocarcinoma cells).

Anticancer Potential of Betulonic Acid Derivatives

Clinical trials have evidenced that several natural compounds, belonging to the phytochemical classes of alkaloids, terpenes, phenols and flavonoids, are effective for the management of various types of cancer. Latest research has proven that natural products and their semisynthetic variants may serve as a starting point for new drug candidates with a diversity of biological and pharmacological activities, designed to improve bioavailability, overcome cellular resistance, and enhance therapeutic efficacy. This review was designed to bring an update regarding the anticancer potential of betulonic acid and its semisynthetic derivatives. Chemical derivative structures of betulonic acid including amide, thiol, and piperidine groups, exert an amplification of the in vitro anticancer potential of betulonic acid. With the need for more mechanistic and in vivo data, some derivatives of betulonic acids may represent promising anticancer agents.