Betulinic Acid Decorated with Polar Groups and Blue Emitting BODIPY Dye: Synthesis, Cytotoxicity, Cell-Cycle Analysis and Anti-HIV Profiling

Effect of betulinic acid on MepA efflux pump inhibition in Staphylococcus aureus: Antibacterial and molecular study

Infections caused by pathogenic bacteria have been responsible for a significant number of deaths in recent decades. Invasive infections caused by Staphylococcus aureus are highly prevalent and have high morbidity and mortality rates. Faced with the increase in multidrug-resistant bacteria, a promising strategy is the development of adjuvant molecules that enhance the effects of antibiotics, such as efflux pump inhibitors. Betulinic acid (BA) is a pentacyclic triterpene of the lupane type, found in various plant species, which has shown various pharmacological activities, including antibacterial potential. This study investigated the inhibitory action of BA on the MepA efflux pump in strains of Staphylococcus aureus K2068, as well as carrying out fluorescence and membrane permeability tests. The minimum inhibitory concentrations (MIC) were determined using the broth microdilution method. Subsequently, their effects on efflux pump-mediated antibiotic resistance were evaluated by reducing the MIC of the antibiotic and ethidium bromide (EtBr), while fluorimetry and permeability potential tests were carried out using the SYTOX Green fluorescence method. BA did not show intrinsic antibacterial activity, however it showed synergistic effects when associated with the antibiotics ciprofloxacin and ethidium bromide, inducing a reduction in MIC and indicating inhibitory effects on the MepA efflux pump. BA also induced a significant increase in fluorescence and demonstrated the ability to permeabilize the bacterial membrane. The results obtained show that BA has a high potential to act as an efflux pump inhibitor and could help in the treatment of resistant bacterial infections.

Terpenes and Terpenoids Conjugated with BODIPYs: An Overview of Biological and Chemical Properties

Advancements in small-molecule research have created the need for sensitive techniques to accurately study biological processes in living systems. Fluorescent-labeled probes have become indispensable tools, particularly those that use boron-dipyrromethene (BODIPY) dyes. Terpenes and terpenoids are organic compounds found in nature that offer diverse biological activities, and BODIPY-based probes play a crucial role in studying these compounds. Monoterpene-BODIPY conjugates have exhibited potential for staining bacterial and fungal cells. Sesquiterpene-BODIPY derivatives have been used to study sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA), indicating their potential for drug development. Owing to their unique properties, diterpenes have been investigated using BODIPY conjugates to evaluate their mechanisms of action. Triterpene-BODIPY conjugates have been synthesized for biological studies, with different spacers affecting their cytotoxicity. Fluorescent probes, inspired by terpenoid-containing vitamins, have also been developed. Derivatives of tocopherol, coenzyme Q10, and vitamin K1 can provide insights into their oxidation-reduction abilities. All these probes have diverse applications, including the study of cell membranes to investigate immune responses and antioxidant properties. Further research in this field can help better understand and use terpenes and terpenoids in various biological contexts.

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.

Plant Secondary Metabolites Used for the Treatment of Diseases and Drug Development

The importance of natural products in medicine, and in particular, plant secondary metabolites used for the treatment of diseases and drug development, has been obvious for several thousands of years [...]

Cytotoxic and Anti-Inflammatory Triterpenoids in the Vines and Leaves of Momordica charantia

The vines and leaves of Momordica charantia L. are used as herbal medicines to treat inflammation-related disorders. However, their safety profile remains uncharacterized, and the constituents in their extracts that exert anti-inflammatory and adverse effects remain unclear. This study isolated the characteristic cucurbitane-type triterpenoid species in the vines and leaves of M. charantia L. and analyzed their cytotoxicity, anti-inflammatory effects, and underlying mechanisms. Four structurally related triterpenoids—momordicines I, II, IV, and (23E) 3β,7β,25-trihydroxycucurbita-5,23-dien-19-al (TCD)—were isolated from the triterpenoid-rich fractions of extracts from the vines and leaves of M. charantia. Momordicine I was cytotoxic on normal cells, momordicine II exerted milder cytotoxicity, and momordicine IV and TCD had no obvious adverse effects on cell growth. TCD had anti-inflammatory activity both in vivo and in vitro. In lipopolysaccharide-stimulated RAW 264.7 cells, TCD inhibited the inhibitor kappa B kinase/nuclear factor-κB pathway and enhanced the expression of nuclear factor erythroid 2-related factor 2, heme oxygenase-1, and glutamate-cysteine ligase modifier subunit through the extracellular signal-regulated kinase1/2 and p38. Thus, the vines and leaves of M. charantia should be used with caution. An extraction protocol that can enrich TCD but remove momordicine I would likely enhance the safety of the extract.