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.

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.

The Role of Cyclodextrins in the Design and Development of Triterpene-Based Therapeutic Agents.

Triterpenic compounds stand as a widely investigated class of natural compounds due to their remarkable therapeutic potential. However, their use is currently being hampered by their low solubility and, subsequently, bioavailability. In order to overcome this drawback and increase the therapeutic use of triterpenes, cyclodextrins have been introduced as water solubility enhancers; cyclodextrins are starch derivatives that possess hydrophobic internal cavities that can incorporate lipophilic molecules and exterior surfaces that can be subjected to various derivatizations in order to improve their biological behavior. This review aims to summarize the most recent achievements in terms of triterpene:cyclodextrin inclusion complexes and bioconjugates, emphasizing their practical applications including the development of new isolation and bioproduction protocols, the elucidation of their underlying mechanism of action, the optimization of triterpenes' therapeutic effects and the development of new topical formulations.

Plant-Derived Anticancer Compounds as New Perspectives in Drug Discovery and Alternative Therapy.

Despite the recent advances in the field of chemically synthetized pharmaceutical agents, nature remains the main supplier of bioactive molecules. The research of natural products is a valuable approach for the discovery and development of novel biologically active compounds possessing unique structures and mechanisms of action. Although their use belongs to the traditional treatment regimes, plant-derived compounds still cover a large portion of the current-day pharmaceutical agents. Their medical importance is well recognized in the field of oncology, especially as an alternative to the limitations of conventional chemotherapy (severe side effects and inefficacy due to the occurrence of multi-drug resistance). This review offers a comprehensive perspective of the first blockbuster chemotherapeutic agents of natural origin's (e.g. taxol, vincristine, doxorubicin) mechanism of action using 3D representation. In addition is portrayed the step-by-step evolution from preclinical to clinical evaluation of the most recently studied natural compounds with potent antitumor activity (e.g. resveratrol, curcumin, betulinic acid, etc.) in terms of anticancer mechanisms of action and the possible indications as chemotherapeutic or chemopreventive agents and sensitizers. Finally, this review describes several efficient platforms for the encapsulation and targeted delivery of natural compounds in cancer treatment.

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

Wounds are among the most common skin conditions, displaying a large etiological diversity and being characterized by different degrees of severity. Wound healing is a complex process that involves multiple steps such as inflammation, proliferation and maturation and ends with scar formation. Since ancient times, a widely used option for treating skin wounds are plant- based treatments which currently have become the subject of modern pharmaceutical formulations. Triterpenes with tetracyclic and pentacyclic structure are extensively studied for their implication in wound healing as well as to determine their molecular mechanisms of action. The current review aims to summarize the main results of in vitro, in vivo and clinical studies conducted on lupane, ursane, oleanane, dammarane, lanostane and cycloartane type triterpenes as potential wound healing treatments.

Thermosensitive Betulinic Acid-Loaded Magnetoliposomes: A Promising Antitumor Potential for Highly Aggressive Human Breast Adenocarcinoma Cells Under Hyperthermic Conditions.

PURPOSE: Breast cancer presents one of the highest rates of prevalence around the world. Despite this, the current breast cancer therapy is characterized by significant side effects and high risk of recurrence. The present work aimed to develop a new therapeutic strategy that may improve the current breast cancer therapy by developing a heat-sensitive liposomal nano-platform suitable to incorporate both anti-tumor betulinic acid (BA) compound and magnetic iron nanoparticles (MIONPs), in order to address both remote drug release and hyperthermia-inducing features. To address the above-mentioned biomedical purposes, the nanocarrier must possess specific features such as specific phase transition temperature, diameter below 200 nm, superparamagnetic properties and heating capacity. Moreover, the anti-tumor activity of the developed nanocarrier should significantly affect human breast adenocarcinoma cells. METHODS: BA-loaded magnetoliposomes and corresponding controls (BA-free liposomes and liposomes containing no magnetic payload) were obtained through the thin-layer hydration method. The quality and stability of the multifunctional platforms were physico-chemically analysed by the means of RAMAN, scanning electron microscopy-EDAX, dynamic light scattering, zeta potential and DSC analysis. Besides this, the magnetic characterization of magnetoliposomes was performed in terms of superparamagnetic behaviour and heating capacity. The biological profile of the platforms and controls was screened through multiple in vitro methods, such as MTT, LDH and scratch assays, together with immunofluorescence staining. In addition, CAM assay was performed in order to assess a possible anti-angiogenic activity induced by the test samples. RESULTS: The physico-chemical analysis revealed that BA-loaded magnetoliposomes present suitable characteristics for the purpose of this study, showing biocompatible phase transition temperature, a diameter of 198 nm, superparamagnetic features and heating capacity. In vitro results showed that hyperthermia induces enhanced anti-tumor activity when breast adenocarcinoma MDA-MB-231 cells were exposed to BA-loaded magnetoliposomes, while a low cytotoxic rate was exhibited by the non-tumorigenic breast epithelial MCF 10A cells. Moreover, the in ovo angiogenesis assay endorsed the efficacy of this multifunctional platform as a good strategy for breast cancer therapy, under hyperthermal conditions. Regarding the possible mechanism of action of this multifunctional nano-platform, the immunocytochemistry of the MCF7 and MDA-MB-231 breast carcinoma cells revealed a microtubule assembly modulatory activity, under hyperthermal conditions. CONCLUSION: Collectively, these findings indicate that BA-loaded magnetoliposomes, under hyperthermal conditions, might serve as a promising strategy for breast adenocarcinoma treatment.

Lemon Balm Extracts Prevent Breast Cancer Progression In Vitro and In Ovo on Chorioallantoic Membrane Assay.

Breast cancer is the most frequently diagnosed malignant pathology, representing the primary cause of cancer death in women. Natural products are an appealing strategy to limit the progression of the disease. Targeting angiogenesis in breast cancer may positively impact on poor prognosis of breast cancer. As source of natural compounds, we investigated the leaves of Melissa officinalis L. (MO), known as lemon balm, an aromatic plant that spontaneously grows in the South and Western areas of Romania, being traditionally recommended as anxiolytic, antispasmodic, or as digestive remedy. Our aim was to investigate the phytochemical profiling and the antiangiogenic and chemopreventive bioactivity of MO from Banat region, on breast cancer. Two ethanolic extracts of MO (MOE96 and MOE70) and one methanolic extract (MOM80) were subjected to polyphenol and triterpene profiling by HPLC-MS, and the antioxidant capacity was evaluated. The antiangiogenic potential was investigated using the chorioallantoic membrane assay (CAM). The MTT(3-(4,5-dimethylthiazol-2-yl)-2-5-diphenyltetrazolium bromide) assay was used to investigate the cytotoxic effects on MCF-7 and MDA-MB-231breast cancer cells, as well as on MCF-10A normal breast epithelial cells, while apoptosis was performed by DAPI staining. Rosmarinic acid (RA) and ursolic acid (UA) were revealed as dominant phytocompounds. The highest concentration in phytochemicals were found in MOM80; MOE96 was more concentrated in UA, while MOE70 extracted more RA. MOE96 inhibited cancer progression and angiogenesis in the in ovo CAM model using MDA-MB-231 cells, inhibiting breast cancer progression and angiogenesis for the MDA-MB-231 breast cancer cell line; no secondary tumoral areas were registered, indicative for a preventive effect against breast tumor cell invasiveness. The highest cell inhibitory activity was also exhibited by MOE96, in particular against the estrogen receptor positive MCF7 breast cancer cell line, with no cytotoxic effect on healthy cells. The estrogen receptor positive MCF7 cell line proved to be more sensitive to the extract antiproliferative activity than the triple negative MDA-MB-231 breast cancer cell line. Nevertheless, the chemopreventive potential of MOE96 extract is phenotype-dependent and is rather related to the apoptosis and antiangiogenic effects suggesting a multitargeted mechanism of action due to its multiple compound composition next to a concentration ratio of RA : UA in favor of UA.

Improvement of ursolic and oleanolic acids' antitumor activity by complexation with hydrophilic cyclodextrins.

Ursolic and oleanolic acids have been brought into the spotlight of research due to their chemopreventive, anti-inflammatory and immunomodulatory properties. The most important disadvantage of ursolic and oleanolic acids is their weak water solubility which limits their bioavailability. Pentacyclic triterpenes can form inclusion complexes with different types of cyclodextrins which provide the hydrophilic matrix requested for the molecular dispersion of drugs in order to become more water soluble. The aim of the current study is the complexation of ursolic and oleanolic acids with hydrophilic cyclodextrins in order to achieve an improvement of their pharmacological effect. After the virtual screening of the binding affinities between ursolic and oleanolic acids and various cyclodextrins, 2-hydroxypropyl-ß-cyclodextrin and 2-hydroxypropil-γ-cyclodextrin were selected as host-molecules for the inclusion complexation. Using the scanning electron microscopy, differential scanning calorimetry and X-ray diffraction the formation of real inclusion complexes between ursolic and oleanolic acids and the two cyclodextrins was confirmed. The anti-proliferative potential of the complexes was tested in vitro on several melanoma cell lines, using the pure compounds as reference. The complexes exhibited higher in vitro anti-proliferative activity as compared to the pure compounds; this improvement was significant for ursolic acid complexes, the highest activity being reported for the 2-hydroxypropil-γ-cyclodextrin complex. Weaker results were recorded for the oleanolic acid complexes where 2-hydroxypropyl-ß-cyclodextrin proved to be the most fitted inclusion partner. The entrapment of the two active compounds inside ramified hydrophilic cyclodextrins proved to be a suitable option to increase their anti-proliferative activity.

Germinated and Ungerminated Seeds Extract from Two Lupinus Species: Biological Compounds Characterization and In Vitro and In Vivo Evaluations.

In recent years, nutraceuticals attracted a great amount of attention in the biomedical research due to their significant contribution as natural agents for prevention of various health issues. Ethanolic extracts from the ungerminated and germinated seeds of Lupinus albus L. and Lupinus angustifolius L. were analyzed for the content in isoflavones (genistein) and cinnamic acid derivatives. Additionally, the extracts were evaluated for antimicrobial, antiproliferative, and anti-inflammatory properties, using in vitro and in vivo tests. Germination proved to be a method of choice in increasing the amount of genistein and cinnamic acid derivatives in both Lupinus albus L. and Lupinus angustifolius L. seeds. Biological evaluation of all vegetal extracts revealed a weak therapeutic potential for both ungerminated and germinated seeds.