Antimicrobial activity of oleanolic and ursolic acids: an update

Hepatoprotective Plants from Bangladesh: A Biophytochemical Review and Future Prospect

Liver diseases are quite prevalant in many densely populated countries, including Bangladesh. The liver and its hepatocytes are targeted by virus and microbes, as well as by chemical environmental toxicants, causing wide-spread disruption of metabolic fuctions of the human body, leading to death from end-stage liver diseases. The aim of this review is to systematically explore and record the potential of Bangladeshi ethnopharmacological plants to treat liver diseases with focus on their sources, constituents, and therapeutic uses, including mechanisms of actions (MoA). A literature survey was carried out using Pubmed, Google Scholar, ScienceDirect, and Scopus databases with articles reported until July, 2020. A total of 88 Bangladeshi hepatoprotective plants (BHPs) belonging to 47 families were listed in this review, including Euphorbiaceae, Cucurbitaceae, and Compositae families contained 20% of plants, while herbs were the most cited (51%) and leaves were the most consumed parts (23%) as surveyed. The effect of BHPs against different hepatotoxins was observed via upregulation of antioxidant systems and inhibition of lipid peroxidation which subsequently reduced the elevated liver biomarkers. Different active constituents, including phenolics, curcuminoids, cucurbitanes, terpenoids, fatty acids, carotenoids, and polysaccharides, have been reported from these plants. The hepatoameliorative effect of these constituents was mainly involved in the reduction of hepatic oxidative stress and inflammation through activation of Nrf2/HO-1 and inhibition of NF-κB signaling pathways. In summary, BHPs represent a valuable resource for hepatoprotective lead therapeutics which may offer new alternatives to treat liver diseases.

Review on the Antibacterial Mechanism of Plant-Derived Compounds against Multidrug-Resistant Bacteria (MDR)

Microbial resistance has progressed rapidly and is becoming the leading cause of death globally. The spread of antibiotic-resistant microorganisms has been a significant threat to the successful therapy against microbial infections. Scientists have become more concerned about the possibility of a return to the pre-antibiotic era. Thus, searching for alternatives to fight microorganisms has become a necessity. Some bacteria are naturally resistant to antibiotics, while others acquire resistance mainly by the misuse of antibiotics and the emergence of new resistant variants through mutation. Since ancient times, plants represent the leading source of drugs and alternative medicine for fighting against diseases. Plants are rich sources of valuable secondary metabolites, such as alkaloids, quinones, tannins, terpenoids, flavonoids, and polyphenols. Many studies focus on plant secondary metabolites as a potential source for antibiotic discovery. They have the required structural properties and can act by different mechanisms. This review analyses the antibiotic resistance strategies produced by multidrug-resistant bacteria and explores the phytochemicals from different classes with documented antimicrobial action against resistant bacteria, either alone or in combination with traditional antibiotics.

Improvement of skin lesions in corticosteroid withdrawal-associated severe eczema by multicomponent traditional Chinese medicine therapy

Rationale

We recently showed that multicomponent traditional Chinese medicine (TCM) therapy had steroid-sparing effects in moderate-to-severe eczema. We sought to evaluate TCM effects in severe eczema in a 7-year-old male with refractory disease and corticosteroid withdrawal syndrome.

Methods

Prior to referral, the patient had been treated since infancy with increasingly intensive standard of care, including high-dose topical and systemic corticosteroid and antibiotic therapy and was unable to tolerate further steroid treatment. The patient was administered a combination of oral and topical TCM for 17 months following discontinuation of his steroid regimen. His overall medical condition was assessed by SCORAD criteria and laboratory evaluations of serum IgE, absolute eosinophil count, and liver and kidney function tests.

Results

The patient showed rapid improvement of clinical measures of disease after starting TCM therapy, with marked improvement of sleep quality within the first week, complete resolution of itching, oozing, and erythema at 2 weeks, and a 79% and 99% decrease in his SCORAD values after one month and 3–6 months of TCM, respectively. Serum total IgE decreased by 75% (from 19,000 to 4630 (kIU/L), and absolute eosinophil counts decreased by 60% (from 1000 to 427 cells/μL) after 12 months of treatment. The patient did not require oral or topical steroids during the 17-month trial of TCM. TCM was tapered without complications. His dermatologic manifestations continued to be well-controlled 3 months after discontinuation.

Conclusion

This case study suggests TCM should be further evaluated in controlled clinical studies of patients with severe, refractory eczema and steroid withdrawal syndrome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13223-021-00555-0.

Identification of phytochemical inhibitors against main protease of COVID-19 using molecular modeling approaches

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a novel corona virus that causes corona virus disease 2019 (COVID-19). The COVID-19 rapidly spread across the nations with high mortality rate even as very little is known to contain the virus at present. In the current study, we report novel natural metabolites namely, ursolic acid, carvacrol and oleanolic acid as the potential inhibitors against main protease (Mpro) of COVID-19 by using integrated molecular modeling approaches. From a combination of molecular docking and molecular dynamic (MD) simulations, we found three ligands bound to protease during 50 ns of MD simulations. Furthermore, the molecular mechanic/generalized/Born/Poisson-Boltzmann surface area (MM/G/P/BSA) free energy calculations showed that these chemical molecules have stable and favourable energies causing strong binding with binding site of Mpro protein. All these three molecules, namely, ursolic acid, carvacrol and oleanolic acid, have passed the ADME (Absorption, Distribution, Metabolism, and Excretion) property as well as Lipinski's rule of five. The study provides a basic foundation and suggests that the three phytochemicals, viz. ursolic acid, carvacrol and oleanolic acid could serve as potential inhibitors in regulating the Mpro protein's function and controlling viral replication. Communicated by Ramaswamy H. Sarma.

The Introduction of Hydrazone, Hydrazide, or Azepane Moieties to the Triterpenoid Core Enhances an Activity Against M. tuberculosis

BACKGROUND

Triterpenoids exhibit a wide spectrum of antimicrobial activity.

OBJECTIVE

The objective of this study was to synthesize a series of nitrogen derivatives based on lupane, oleanane, and ursane triterpenoids with high antitubercular activity.

METHODS

Isonicotinoylhydrazones were prepared via the reaction of 3-oxotriterpenic acids or betulonic aldehyde with isoniazid (INH) in yields of 54-72%. N-Acylation of betulonic or azepanobetulinic acids led to lupane C28 hydrazides and dihydrazides. The derivatives were evaluated for their in vitro antimycobacterial activities against Mycobacterium tuberculosis (MTB) H37RV and single-drug resistance (SDR)-TB in the National Institute of Allergy and Infectious Diseases, USA. Molecular docking was performed to evaluate the possible binding modes of investigated compounds in the active site of Diterpene synthase (Rv3378c).

RESULTS

The obtained compounds are represented by C3 or C28 conjugates with hydrazine hydrate or INH. Some compounds demonstrated from high minimum inhibitory concentration (MIC ≤ 10 μg/mL) to excellent (MICs from 0.19 to 1.25 μg/mL) activity against MTB H37RV. Two lupane conjugates with INH were the leading compounds against MTB H37RV and some SDR-strains with MICs ranged from 0.19 to 1.70 μg/mL. Molecular docking of active compounds to diterpene synthase showed that these moieties accommodate the active site of the enzyme.

CONCLUSION

It was revealed that the conjugation of lupanes with INH at C3 is more effective than at C28 and the lupane skeleton is preferable among oleanane and ursane types. The replacement of native hexacarbocyclic A ring to seven-member azepane ring is favorably for inhibition of both MTB H37RV and SDR-strains. These data could possibly mean that the antitubercular activity against INH-resistant strains (INH-R) came from both triterpenoid and isoniazid parts of the hybrid molecules. Azepanobetulin showed the highest activity against both INH-R strains in comparison with other triterpenoids and INH. Thus, the introduction of hydrazone, hydrazide (dihydrazide), or azepane moieties into the triterpenoid core is a promising way for the development of new anti-tubercular agents.

Synthesis and Biological Activity of Triterpene-Coumarin Conjugates

A set of 12 maslinic acid-coumarin conjugates was synthesized, with 9 being maslinic acid-diamine-coumarin conjugates at the C-28 carboxylic acid group of triterpene acid and the other three being maslinic acid-coumarin conjugates at C-2/C-3 and/or C-28 of the triterpene skeleton. The cytotoxic effects of these 12 triterpene conjugates were evaluated in three cancer cell lines (B16-F10, HT29, and Hep G2) and compared, respectively, with three nontumor cell lines from the same or similar tissue (HPF, IEC-18, and WRL68). The most potent cytotoxic results were achieved by a conjugate with two molecules of coumarin-3-carboxylic acid coupled through the C-2 and C-3 hydroxy groups of maslinic acid. This conjugate showed submicromolar IC₅₀ values in two of the three cancer cell lines tested (0.6, 1.1, and 0.9 μM), being between 110- and 30-fold more effective than its corresponding precursor. Furthermore, this conjugate (10) showed percentages of cell viability for the three nontumor lines of 90%. Four maslinic acid-coumarin conjugates displayed apoptotic effects in the treated cells, with total apoptosis rates of between 40 and 85%, relative to the control. Almost all the compounds assayed caused cell-cycle arrest in all cancer cell lines, increasing the number of these cells in the G0/G1 phase.

Ursolic and Oleanolic Acids: Plant Metabolites with Neuroprotective Potential

Ursolic and oleanolic acids are secondary plant metabolites that are known to be involved in the plant defence system against water loss and pathogens. Nowadays these triterpenoids are also regarded as potential pharmaceutical compounds and there is mounting experimental data that either purified compounds or triterpenoid-enriched plant extracts exert various beneficial effects, including anti-oxidative, anti-inflammatory and anticancer, on model systems of both human or animal origin. Some of those effects have been linked to the ability of ursolic and oleanolic acids to modulate intracellular antioxidant systems and also inflammation and cell death-related pathways. Therefore, our aim was to review current studies on the distribution of ursolic and oleanolic acids in plants, bioavailability and pharmacokinetic properties of these triterpenoids and their derivatives, and to discuss their neuroprotective effects in vitro and in vivo.

Lupeol acetate as a potent antifungal compound against opportunistic human and phytopathogenic mold Macrophomina phaseolina

Antifungal activity of Monothecabuxifolia methanolic extract and its various fractions were assessed against Macrophominaphaseolina, a soil-borne fungal pathogen of more than 500 vegetal species as well as rare and emerging opportunistic human pathogen. Different concentrations of methanolic extract (3.125 to 200 mg mL⁻¹) inhibited fungal biomass by 39–45%. Isolated n-hexane, chloroform and ethyl acetate fractions suppressed fungal biomass by 32–52%, 29–50% and 29–35%, respectively. Triterpenes lupeol and lupeol acetate (1, 2) were isolated from n-hexane while betulin, β-sitosterol, β-amyrin, oleanolic acid (3–6) were isolated from chloroform fraction. Vanillic acid, protocatechuic acid, kaempferol and quercetin (7–10) were isolated from the ethyl acetate fraction and identified using various spectroscopic techniques namely mass spectroscopy and NMR. Antifungal activity of different concentrations (0.0312 to 2 mg mL⁻¹) of the isolated compounds was evaluated and compared with the activity of a broad spectrum fungicide mancozeb. Different concentrations of mencozeb reduced fungal biomass by 83–85%. Among the isolated compounds lupeol acetate (2) was found the highest antifungal against M.phaseolina followed by betulin (3), vanillic acid (7), protocatechuic acid (8), β-amyrin (5) and oleanolic acid (6) resulting in 79–81%, 77–79%, 74–79%, 67–72%, 68–71% and 68–71%, respectively. Rest of the compounds also showed considerable antifungal activity and reduced M.phaseolina biomass by 41–64%.

A review on the phytochemical and pharmacological properties of Hyptis suaveolens (L.) Poit

BACKGROUND

Plants are the repository of variable number of valuable secondary metabolites that bears pharmacognostic and pharmacological implications having potentiality to emerge as super drugs in future. In-vivo production of these metabolites is influenced by the biotic and abiotic stresses resulting in continuous accumulation of diverse phytochemicals and their derivatives that can be useful in designing and developing potential drugs for future. The aim of the present study is to review the existence of medicinally important secondary metabolites and possible pharmacological and pharmacognostic importance of under-explored weed plant species Hyptis suaveolens (L.) Poit., to explore the potentiality of the plant for developing and designing the drugs for future.

MAIN BODY OF THE ABSTRACT

Hyptis suaveolens belonging to family Lamiaceae is the rich source of medicinally important phytochemicals like essential oils, tannins, saponins, phenols, flavonoids, terpenoids, alkaloids, and sterols. One or many of these compounds have antioxidative, anti-inflammatory, antispasmodic, anti-septic, anti-cancer, anti-ulcer, antimicrobial, antibacterial, antiviral, antifungal, anti-diabetic, anti-fertility, diaphoretics, anticutaneous, anticatarrhal, antirheumatic, anti-ulcer, gastroprotective, immunomodulatory, analgesic, and antiviral activity.

SHORT CONCLUSION

Hyptis suaveolens contains unique terpenoid metabolites like suaveolic acid, suaveolol, methyl suaveolate, beta-sitosterol, ursolic acid, and phenolic compound like rosamarinic acid, methyl rosamarinate that have potentiality to substitute the traditional drugs as therapeutic agent against the resistant and newly emerged bacterial and viral pathogens. Pentacyclic triterpenoid, ursolic acid have been reported to have effective antiviral response against the SARS-CoV2 responsible for the present COVID-19 pandemic and HIV virus for which no effective vaccines are available till date. Ursolic acid has the ability to modulate the activity of main protease (Mpro) that is essential for processing of SARS-CoV2 replicase-transcriptase machinery needed for viral replication and particle assembly.

Effect-Directed Profiling of 17 Different Fortified Plant Extracts by High-Performance Thin-Layer Chromatography Combined with Six Planar Assays and High-Resolution Mass Spectrometry

An effect-directed profiling method was developed to investigate 17 different fortified plant extracts for potential benefits. Six planar effect-directed assays were piezoelectrically sprayed on the samples separated side-by-side by high-performance thin-layer chromatography. Multipotent compounds with antibacterial, α-glucosidase, β-glucosidase, AChE, tyrosinase and/or β-glucuronidase-inhibiting effects were detected in most fortified plant extracts. A comparatively high level of antimicrobial activity was observed for Eleutherococcus, hops, grape pomace, passiflora, rosemary and Eschscholzia. Except in red vine, black radish and horse tail, strong enzyme inhibiting compounds were also detected. Most plants with anti-α-glucosidase activity also inhibited β-glucosidase. Green tea, lemon balm and rosemary were identified as multipotent plants. Their multipotent compound zones were characterized by high-resolution mass spectrometry to be catechins, rosmarinic acid, chlorogenic acid and gallic acid. The results pointed to antibacterial and enzymatic effects that were not yet known for plants such as Eleutherococcus and for compounds such as cynaratriol and caffeine. The nontarget effect-directed profiling with multi-imaging is of high benefit for routine inspections, as it provides comprehensive information on the quality and safety of the plant extracts with respect to the global production chain. In this study, it not only confirmed what was expected, but also identified multipotent plants and compounds, and revealed new bioactivity effects.

Related Pentacyclic Triterpenes Have Immunomodulatory Activity in Chronic Experimental Visceral Leishmaniasis

Leishmaniasis is a neglected tropical disease caused by the flagellated protozoa of the genus Leishmania that affects millions of people around the world. Drugs employed in the treatment of leishmaniasis have limited efficacy and induce local and systemic side effects to the patients. Natural products are an interesting alternative to treat leishmaniasis, because some purified molecules are selective toward parasites and not to the host cells. Thus, the aim of the present study was to compare the in vitro antileishmanial activity of the triterpenes betulin (Be), lupeol (Lu), and ursolic acid (UA); analyze the physiology and morphology of affected organelles; analyze the toxicity of selected triterpenes in golden hamsters; and study the therapeutic activity of triterpenes in hamsters infected with L. (L.) infantum as well as the cellular immunity induced by studied molecules. The triterpenes Lu and UA were active on promastigote (IC₅₀ = 4.0 ± 0.3 and 8.0 ± 0.2 μM, respectively) and amastigote forms (IC₅₀ = 17.5 ± 0.4 and 3.0 ± 0.2 μM, respectively) of L. (L.) infantum, and their selectivity indexes (SI) toward amastigote forms were higher (≥13.4 and 14, respectively) than SI of miltefosine (2.7). L. (L.) infantum promastigotes treated with Lu and UA showed cytoplasmic degradation, and in some of these areas, cell debris were identified, resembling autophagic vacuoles, and parasite mitochondria were swelled, fragmented, and displayed membrane potential altered over time. Parasite cell membrane was not affected by studied triterpenes. Studies of toxicity in golden hamster showed that Lu did not alter blood biochemical parameters associated with liver and kidney functions; however, a slight increase of aspartate aminotransferase level in animals treated with 2.5 mg/kg of UA was detected. Lu and UA triterpenes eliminated amastigote forms in the spleen (87.5 and 95.9% of reduction, respectively) and liver of infected hamster (95.9 and 99.7% of reduction, respectively); and UA showed similar activity at eliminating amastigote forms in the spleen and liver than amphotericin B (99.2 and 99.8% of reduction). The therapeutic activity of both triterpenes was associated with the elevation of IFN-γ and/or iNOS expression in infected treated animals. This is the first comparative work showing the in vitro activity, toxicity, and therapeutic activity of Lu and UA in the chronic model of visceral leishmaniasis caused by L. (L.) infantum; additionally, both triterpenes activated cellular immune response in the hamster model of visceral leishmaniasis.

Regioselective Hydroxylation of Oleanolic Acid Catalyzed by Human CYP3A4 to Produce Hederagenenin, a Chiral Metabolite

Oleanolic acid (OA) is a pentacyclic triterpenoid widely found in plants and foods as an aglycone of triterpenoid saponins or as a free acid. OA exhibits beneficial activities for humans, including antitumor, antivirus, and hepatoprotection properties without apparent toxicity. The metabolites produced by the cytochrome P450 (P450) enzymes are critical for the evaluation of the efficacy and safety of drugs. In this study, the potential metabolites of OA were investigated by P450-catalyzed oxidation reactions. Among the various tested human P450s, only human CYP3A4 was active for the hydroxylation of OA. The major metabolite was characterized by a set of analyses using HPLC, LC–MS, and NMR. It was found to be 4-epi-hederagenenin, a chiral product, by regioselective hydroxylation of the methyl group at the C-23 position. These results indicated that CYP3A4 can hydroxylate an OA substrate to make 4-epi-hederagenenin. Possible drug–food interactions are discussed.

Network pharmacology for the identification of phytochemicals in traditional Chinese medicine for COVID-19 that may regulate interleukin-6

OBJECTIVE

´Three formulas and three medicines,' namely, Jinhua Qinggan Granule, Lianhua Qingwen Capsule, Xuebijing Injection, Qingfei Paidu Decoction, HuaShi BaiDu Formula, and XuanFei BaiDu Granule, were proven to be effective for coronavirus disease 2019 (COVID-19) treatment. The present study aimed to identify the active chemical constituents of this traditional Chinese medicine (TCM) and investigate their mechanisms through interleukin-6 (IL-6) integrating network pharmacological approaches.

METHODS

We collected the compounds from all herbal ingredients of the previously mentioned TCM, but those that could down-regulate IL-6 were screened through the network pharmacology approach. Then, we modeled molecular docking to evaluate the binding affinity between compounds and IL-6. Furthermore, we analyzed the biological processes and pathways of compounds. Finally, we screened out the core genes of compounds through the construction of the protein-protein interaction network and the excavation of gene clusters of compounds.

RESULTS

The network pharmacology research showed that TCM could decrease IL-6 using several compounds, such as quercetin, ursolic acid, luteolin, and rutin. Molecular docking results showed that the molecular binding affinity with IL-6 of all compounds except γ-aminobutyric acid was < -5.0 kJ/mol, indicating the potential of numerous active compounds in TCM to directly interact with IL-6, leading to an anti-inflammation effect. Finally, Cytoscape 3.7.2 was used to topologize the biological processes and pathways of compounds, revealing potential mechanisms for COVID-19 treatment.

CONCLUSION

These results indicated the positive effect of TCM on the prevention and rehabilitation of COVID-19 in at-risk people. Quercetin, ursolic acid, luteolin, and rutin could inhibit COVID-19 by down-regulating IL-6.

Effect of water extracts from Cynanchum thesioides (Freyn) K. Schum. on visceral hypersensitivity and gut microbiota profile in maternally separated rats

ETHNOPHARMACOLOGICAL RELEVANCE

Irritable bowel syndrome (IBS) is a chronic, stress-related, functional gastrointestinal disorder characterized by abdominal discomfort and altered bowel habits; the manipulation of the microbiota is emerging as a promising therapeutic option for IBS. Cynanchum thesioides (CT) is an herb of traditional Mongolian medicine that has been employed in treating abdominal pain and diarrhea for hundreds of years. Phytochemical studies of this plant showed the presence of various flavonoids with antibacterial and anti-inflammatory activities. We hypothesized that Cynanchum thesioides manipulates the gut mycobiome and reverses visceral hypersensitivity in IBS rat model.

PURPOSE OF THE STUDY

The aims of this study were to prove the in vivo efficacy of Cynanchum thesioides on improving visceral hypersensitivity in IBS rat model and to examine its effect on gut bacterial communities, focusing on the potential interrelationships among microbiota and visceral hypersensitivity.

MATERIALS AND METHODS

We induced visceral hypersensitivity rat models by maternal separation (MS) of Sprague-Dawley rats, and administered CT water extracts to MS rats for 10 consecutive days. The abdominal withdrawal reflex score and threshold of colorectal distention were employed to assess visceral sensitivity. We then used the Illumina HiSeq platform to analyze bacterial 16S rRNA gene.

RESULTS

Treatment with CT improved visceral hypersensitivity in MS rats, and this was accompanied by alterations in the structure and composition of the gut microbiota. The extent of the stability of the gut microbiota was improved after treatment with CT. The genera Pseudomonas, Lachnospiracea_incertae_sedis, and Clostridium XlVa (which were more prevalent in MS rats) were significantly decreased, whereas the abundance of some genera were less prevalent in MS rats-for example, Clostridium IV, Elusimicrobium, Clostridium_sensu_stricto, and Acetatifactor were significantly enriched after treatment with CT.

CONCLUSION

Water-extracted CT was beneficial against visceral hypersensitivity in IBS and favorably affected the structure, composition, and functionality of gut microbiota. CT is therefore a promising agent in therapy of IBS.

Enhanced Antioxidant Activity of Ursolic Acid by Complexation with Copper (II): Experimental and Theoretical Study

The copper (II) complex of ursolic acid (Cu(II) UA) was synthesized and discussed in terms of its infrared, UV-visible spectra, quantum-chemical calculations at B3LYP/6-31G(d) level and antioxidant capacity. The copper (II) complex was stable in methanolic solution with the molar ratio metal:ligand 1:1. The data obtained by FT-IR confirmed the metal ion coordination through the carboxylate anion. The antioxidant properties of ursolic acid and its complex with Cu were discussed on the basis of energy of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and values of chemical reactivity parameters. The antiradical properties of ursolic acid and the Cu (II) complex were examined against DPPH• and HO• radicals, and the ferric reducing antioxidant power (FRAP) was examined. The Cu(II) complex showed higher antioxidant activity than ursolic acid, i.e., in DPPH• assay, the EC50 for UA was 47.0 mM, whereas, for Cu(II), UA EC50 = 19.5 mM; the FRAP value for UA was 20.8 µMFe2+, and 35.4 µMFe2+ for Cu(II) UA (compound concentration 3 mM). Although there was no distinct difference in the antioxidant activity against HO• between these two chemicals, they were both better HO• scavengers than DPPH• and showed different kinetics in the reaction with DPPH•.

Sterols and Triterpenes: Antiviral Potential Supported by In-Silico Analysis

The acute respiratory syndrome caused by the novel coronavirus (SARS-CoV-2) caused severe panic all over the world. The coronavirus (COVID-19) outbreak has already brought massive human suffering and major economic disruption and unfortunately, there is no specific treatment for COVID-19 so far. Herbal medicines and purified natural products can provide a rich resource for novel antiviral drugs. Therefore, in this review, we focused on the sterols and triterpenes as potential candidates derived from natural sources with well-reported in vitro efficacy against numerous types of viruses. Moreover, we compiled from these reviewed compounds a library of 162 sterols and triterpenes that was subjected to a computer-aided virtual screening against the active sites of the recently reported SARS-CoV-2 protein targets. Interestingly, the results suggested some compounds as potential drug candidates for the development of anti-SARS-CoV-2 therapeutics.

Antihypertensive activity of oleanolic acid is mediated via downregulation of secretory phospholipase A2 and fatty acid synthase in spontaneously hypertensive rats

Oleanolic acid (OA) is reported to possess antihypertensive activity via the regulation of lipid metabolism; however, the mechanisms underlying lipid regulation by OA are yet to be fully elucidated. The aim of the present study was to evaluate the mechanisms via which OA regulates lipid metabolism in spontaneously hypertensive rats (SHRs) via ultra‑performance liquid chromatography‑quadrupole/Orbitrap‑mass spectrometry (MS)‑based lipidomics analysis. SHRs were treated with OA (1.08 mg/kg) for 4 weeks. The liver tissues were excised, homogenized in dichloromethane and centrifuged, and subsequently the supernatant layer was collected and concentrated under vacuum to dryness. The dichloromethane extract was subjected to MS analysis and database searching, and comparison of standards was performed to identify potential biomarkers. Partial least squares‑discriminant analysis performed on the liver lipidome revealed a total of 14 endogenous metabolites that were significantly changed in the SHR model group (SH group) compared with Wistar Kyoto rats [normal control (NC group)], including glycerophospholipids, sphingolipids and glycerides. Heatmaps revealed that the liver lipid profiles in the OA group were clustered more closely compared with those observed in the NC group, indicating that the antihypertensive effect of OA was mediated via regulation of liver lipid metabolites. It was observed that the protein levels of secretory phospholipase A2 (sPLA2) and fatty acid synthase (FAS) were increased in the SH group compared with the NC group. In addition, the levels of lysophosphatidylcholine and triglycerides in the liver were elevated, whereas the levels of low‑density lipoprotein cholesterol and high‑density lipoprotein cholesterol were reduced in the SH group. Upon treatment with OA, the mRNA and protein levels of PLA2 and FAS were observed to be downregulated. Collectively, the present study indicated that the antihypertensive activity of OA was mediated via downregulation of sPLA2 and FAS in SHRs, and that treatment with OA resulted in significant improvements in blood pressure and associated abnormalities in the lipid metabolites.

A Review on Recent Trends in Green Synthesis of Gold Nanoparticles for Tuberculosis

Tuberculosis (TB) is a contagious disease that has affected mankind. The anti-TB treatment has been used from ancient times to control symptoms of this disease but these medications produced some serious side effects. Herbal products have been successfully used for the treatment of TB. Gold is the most biocompatible metal among all available for biomedical purposes so Gold nanoparticles (GNPs) have sought attention as an attractive biosynthesized drug to be studied in recent years for bioscience research. GNPs are used as better catalysts and due to unique small size, physical resemblance to physiological molecules, biocompatibility and non-cytotoxicity extensively used for various applications including drug and gene delivery. Greenly synthesized GNPs have much more potential in different fields because phytoconstituents used in GNP synthesis itself act as reducing and capping agents and produced more stabilized GNPs. This review is devoted to a discussion on GNPs synthesis with herbs for TB. The main focus is on the role of the natural plant bio-molecules involved in the bioreduction of metal salts during the GNPs synthesis with phytoconstituents used as antitubercular agents.

Molecular Insights into the Interaction of Ursolic Acid and Cucurbitacin from Colocynth with Therapeutic Targets of Mycobacterium tuberculosis

Aims:

Medicinal plants like Citrullus colocynthis are a potential choice to produce helpful novel antimycobacterial drugs. The existence of a range of natural products in the plants, especially Ursolic Acid (UA) and cucurbitacin E 2-0-β-d-glucopyranoside (CEG), with promising antibacterial activity against a variety of bacteria, prompted the need to check its actions against Mycobacterium tuberculosis (Mtb).

Background:

Mycobacterium tuberculosis (Mtb), an obligate human pathogen causes tuberculosis and is one of the major causes of death worldwide. A few combinations of drugs are currently accessible for treating TB patients, but these are inadequate to tackle worldwide TB cases.

Objective:

The molecular interactions between ursolic acid and cucurbitacin E with the eight potential Mtb target proteins were investigated with the objective of finding drug-like inhibitors.

Methods:

Avogadro v.1.2.0 and Openbabel v.2.4.1 were used for creating file formats required for docking analysis. Molecular docking was performed with eight different proteins essential for Mtb metabolism and survival. AutoDock v.4.2 and AutoDock vina v.1.1.2 were used for docking and Gromacs 5.1.4 was used for simulation studies.

Results and Discussion:

Among the two ligands used in this research, cucurbitacin E showed a better docking score relative to the drugs presently available for all the target proteins. Rifampicin showed the best binding affinity (among known inhibitors) i.e. -10.8 kcal/mol with C terminal caspase recruitment domain. Moreover, ursolic acid and cucurbitacin E showed uniform binding score (above -7.5 kcal/mol) with all the target proteins, acknowledged its availability as a potential multi-target drug.

Conclusion:

Ursolic acid can be useful in the creation of novel, multi-targeted and effective anti- TB medicines since it showed stable structure with FabH.

Cuticular waxes of nectarines during fruit development in relation to surface conductance and susceptibility to Monilinia laxa

The cuticle is composed of cutin and cuticular waxes, and it is the first protective barrier to abiotic and biotic stresses in fruit. In this study, we analysed the composition of and changes in cuticular waxes during fruit development in nectarine (Prunus persica L. Batsch) cultivars, in parallel with their conductance and their susceptibility to Monilinia laxa. The nectarine waxes were composed of triterpenoids, mostly ursolic and oleanolic acids, phytosterols, and very-long-chain aliphatics. In addition, we detected phenolic compounds that were esterified with sugars or with triterpenoids, which are newly described in cuticular waxes. We quantified 42 compounds and found that they changed markedly during fruit development, with an intense accumulation of triterpenoids during initial fruit growth followed by their decrease at the end of endocarp lignification and a final increase in very-long-chain alkanes and hydroxylated triterpenoids until maturity. The surface conductance and susceptibility to Monilinia decreased sharply at the beginning of endocarp lignification, suggesting that triterpenoid deposition could play a major role in regulating fruit permeability and susceptibility to brown rot. Our results provide new insights into the composition of cuticular waxes of nectarines and their changes during fruit development, opening new avenues of research to explore brown rot resistance factors in stone fruit.

Oleanolic Acid Derived from Plants: Synthesis and Pharmacological Properties of A-ring Modified Derivatives

Background:

Oleanolic Acid (OA) is a ubiquitous product of triterpenoid compounds. Due to its inexpensive availability, unique bioactivities, pharmacological effects and non-toxic properties, OA has attracted tremendous interest in the field of drug design and synthesis. Furthermore, many OA derivatives have been developed for ameliorating the poor water solubility and bioavailability.

Objective:

Over the past few decades, various modifications of the OA framework structure have led to the observation of enhancement in bioactivity. Herein, we focused on the synthesis and medicinal performance of OA derivatives modified on A-ring. Moreover, we clarified the relationship between structures and activities of OA derivatives with different functional groups in A-ring. The future application of OA in the field of drug design and development also was discussed and inferred.

Conclusion:

This review concluded the novel achievements that could add paramount information to the further study of OA-based drugs.

Plant Soft Rot Development and Regulation from the Viewpoint of Transcriptomic Profiling

Soft rot caused by Pectobacterium species is a devastating plant disease poorly characterized in terms of host plant responses. In this study, changes in the transcriptome of tobacco plants after infection with Pectobacterium atrosepticum (Pba) were analyzed using RNA-Seq. To draw a comprehensive and nontrivially itemized picture of physiological events in Pba-infected plants and to reveal novel potential molecular "players" in plant-Pba interactions, an original functional gene classification was performed. The classifications present in various databases were merged, enriched by "missed" genes, and divided into subcategories. Particular changes in plant cell wall-related processes, perturbations in hormonal and other regulatory systems, and alterations in primary, secondary, and redox metabolism were elucidated in terms of gene expression. Special attention was paid to the prediction of transcription factors (TFs) involved in the disease's development. Herewith, gene expression was analyzed within the predicted TF regulons assembled at the whole-genome level based on the presence of particular cis-regulatory elements (CREs) in gene promoters. Several TFs, whose regulons were enriched by differentially expressed genes, were considered to be potential master regulators of Pba-induced plant responses. Differential regulation of genes belonging to a particular multigene family and encoding cognate proteins was explained by the presence/absence of the particular CRE in gene promoters.

Anti-adipogenic 18,19-seco-ursane stereoisomers and oleane-type saponins from Ilex cornuta leaves

Three undescribed seco-ursane stereoisomers, ilexcornutosides A-C, two undescribed triterpenoid saponins, ilexcornutosides D-E, and 11 known triterpenoids were isolated from the leaves of Ilex cornuta Lindl. & Paxton. Ilexcornutosides A-C and F with the same planar structures are unique 13(18)-ene-18,19-seco-ursane skeleton triterpenoids, identified as (3S,12R)-3-O-[β-d-glucopyranosyl-(1 → 2)-α-l-arabinopyranosyl]-12-hydroxyl-19-oxo-18,19-secours-13(18)-en-28,21-lactone. Among them, ilexcornutosides A and F (or ilexcornutosides B and C) are a pair of diastereomers at the C-20 position; ilexcornutosides A and C (or ilexcornutosides B and F) are a pair of diastereomers with epimerization at the C-21. Their structures were established by extensive spectroscopic (IR, 1D and 2D NMR, and HR-ESI-MS) and chemical analyses. The absolute configurations of ilexcornutosides A, B, D and F were determined by a single crystal X-ray diffraction analysis with a Cu Kα radiation. The inhibitory effect of ilexcornutosides A-F on the PPARγ expression was assessed in the 3T3-L1-Lenti-PPARγ-Luc cells using a single luciferase reporter assay. Ilexcornutosides A and C showed a comparable activity in decrease of the PPARγ expression to the positive control (T0070907) at 5 μM.

Anticancer Activity of Novel Plant Extracts and Compounds from Adenosma bracteosum (Bonati) in Human Lung and Liver Cancer Cells

Cancer is the second leading cause of death globally, and despite the advances in drug development, it is still necessary to develop new plant-derived medicines. Compared with using conventional chemical drugs to decrease the side effects induced by chemotherapy, natural herbal medicines have many advantages. The present study aimed to discover the potential cytotoxicity of ethanol extract and its derived fractions (chloroform, ethyl acetate, butanol, and aqueous) of Adenosma bracteosum Bonati. (A. bracteosum) on human large cell lung carcinoma (NCI-H460) and hepatocellular carcinoma (HepG2). Among these fractions, the chloroform showed significant activity in the inhibition of proliferation of both cancerous cells because of the presence of bioactive compounds including xanthomicrol, 5,4'-dihydroxy-6,7,8,3'-tetramethoxyflavone, and ursolic acid which were clearly revealed by nuclear magnetic resonance spectroscopy (1H-NMR, 13C-NMR, Heteronuclear Multiple Bond Coherence, and Heteronuclear Single Quantum Coherence Spectroscopy) analyses. According to the radical scavenging capacity, the 5,4'-dihydroxy-6,7,8,3'-tetramethoxyflavone compound (AB2) exhibited the highest anticancer activity on both NCI-H460 and HepG2 with IC50 values of 4.57 ± 0.32 and 5.67 ± 0.09 µg/mL respectively, followed by the ursolic acid with the lower percent inhibition at 13.05 ± 0.55 and 10.00 ± 0.16 µg/mL, respectively (p < 0.05). Remarkably, the AB2 compound induced to significant increase in the production of reactive oxygen species accompanied by attenuation of mitochondrial membrane potential, thus inducing the activation of caspase-3 activity in both human lung and liver cancer cells. These results suggest that A. bracteosum is a promising source of useful natural products and AB2 offers opportunities to develop the novel anticancer drugs.

Terpenoids as Potential Geroprotectors

Terpenes and terpenoids are the largest groups of plant secondary metabolites. However, unlike polyphenols, they are rarely associated with geroprotective properties. Here we evaluated the conformity of the biological effects of terpenoids with the criteria of geroprotectors, including primary criteria (lifespan-extending effects in model organisms, improvement of aging biomarkers, low toxicity, minimal adverse effects, improvement of the quality of life) and secondary criteria (evolutionarily conserved mechanisms of action, reproducibility of the effects on different models, prevention of age-associated diseases, increasing of stress-resistance). The number of substances that demonstrate the greatest compliance with both primary and secondary criteria of geroprotectors were found among different classes of terpenoids. Thus, terpenoids are an underestimated source of potential geroprotectors that can effectively influence the mechanisms of aging and age-related diseases.

Potential of the natural products against leishmaniasis in Old World - a review of in-vitro studies

Leishmaniasis is a vector-borne disease among the 10 most Neglected Tropical Diseases with diverse clinical manifestations caused by protozoan parasites of the Leishmania genus. Around 80% of leishmaniasis cases are found in the Old World affecting populations mainly in low and middle-income countries. Its control relies mostly on chemotherapy which still presents many drawbacks. Natural products may offer an inexhaustible source of chemical diversity with therapeutic potential. Despite the lack of knowledge on traditional products with activity against Leishmania parasites, many reports describe the search for natural extracts and compounds with antileishmanial properties against promastigote and amastigote parasite forms. This review summarizes the research of 74 publications of the last decade (2008-2018) focused on the identification of endemic plant-derived products that are active against Old World Leishmania parasites responsible for cutaneous and visceral leishmaniasis. The present review combines data on antileishmanial activity of 423 plants species, belonging to 94 different families, including a large range of crude extracts which lead to the isolation of 86 active compounds. Most studied plants came from Asia and most promising plant families for antileishmanial activity were Asteraceae and Lamiaceae. From the chemical point of view, terpenoids were the most frequently isolated natural products. These studies suggest that natural products isolated from Old World flora are a rich source of new chemical scaffolds for future leishmaniasis treatment as well as for other Neglected Tropical Diseases warranting further investigation.

Antiurolithiatic effects of pentacyclic triterpenes: The distance traveled from therapeutic aspects

Globally, approximately 12% of the population is inflicted by various types of urolithiasis. Standard treatments are available both to avert and treat urolithiasis, but with significant adverse side effects. Pentacyclic triterpenes represent a group of naturally occurring compounds which holds immense potential as therapeutic for treating kidney stone. This review aims to provide an integrative description on how pentacyclic triterpenes can effectively treat calcium oxalate urolithiasis through various mechanisms such as antioxidant, anti-inflammatory, diuretic, and angiotensin-converting enzyme inhibition. Some of the pentacylic triterpenes which shows promising activities include lupeol, oleanolic acid, betulin, and taraxasterol. Moreover, future perspectives in the development of pentacyclic triterpenes in formulations/drugs for urinary stone prevention are highlighted. It is anticipated that compiled information would serve as a scientific baseline to advocate further investigations on the potential of pentacyclic triterpenes in urolithiasis remediation.

Evaluating the Potential of Ursolic Acid as Bioproduct for Cutaneous and Visceral Leishmaniasis

Leishmaniasis affects around 12 million people worldwide and is estimated to cause the ninth-largest disease burden. There are three main forms of the disease, visceral (VL), cutaneous (CL), and mucocutaneous (MCL), leading to more than one million new cases every year and several thousand deaths. Current treatments based on chemically synthesized molecules are far from ideal. In this study, we have tested the in vitro and in vivo efficacy of ursolic acid (UA), a multifunctional triterpenoid with well-known antitumoral, antioxidant, and antimicrobial effects on different Leishmania strains. The in vitro antileishmanial activity against the intracellular forms was six and three-fold higher compared to extracellular forms of L. amazonensis and L. infantum, respectively. UA also showed to be a potent antileishmanial drug against both VL and CL manifestations of the disease in experimental models. UA parenterally administered at 5 mg/kg for seven days significantly reduced the parasite burden in liver and spleen not only in murine acute infection but also in a chronic-infection model against L. infantum. In addition, UA ointment (0.2%) topically administered for four weeks diminished (50%) lesion size progression in a chronic infection model of CL caused by L. amazonensis, which was much greater than the effect of UA formulated as an O/W emulsion. UA played a key role in the immunological response modulating the Th1 response. The exposure of Leishmania-infected macrophages to UA led to a significant different production in the cytokine levels depending on the Leishmania strain causing the infection. In conclusion, UA can be a promising therapy against both CL and VL.

Nutritional and other health properties of olive pomace oil

Olive-pomace oil is rich in oleic acid, and thus it can be an interesting dietary fat alternative as it can allow reaching the recommendation of consuming 20% of total diet energy in the form of monounsaturated fatty acids. In addition, olive-pomace oil also contains a wide range of minor components that may contribute to its healthy properties. The major components identified with healthy properties are triterpenic dialcohols and acids, squalene, tocopherols, sterols, fatty alcohols and phenolic compounds. The refining process, that the crude pomace-oil must undergo for commercial purposes, significantly reduces the content of phenolic compounds, while the other minor components remain at concentrations which can induce positive health effects, especially on cardiovascular health, outstanding pentacyclic triterpenes and aliphatic fatty alcohols in olive-pomace oil. Numerous in vitro and preclinical studies support that mainly the pure compounds, or extracts isolated from plant sources, play an important role in preventing cardiovascular disease and risk factors. Likewise, tocopherols, squalene and phytosterols, in addition to the minor fraction of phenolic compounds, have shown high biological activity with particular association to the cardiovascular function. In the light of the foregoing, and taking into consideration the absence of clinical studies with olive-pomace oil, it would be of great interest to develop randomized, crossover, controlled, double-blind studies to extend the knowledge and understanding on the health effects of olive-pomace olive.

Quantitative trait loci influencing pentacyclic triterpene composition in apple fruit peel

The chemical composition of pentacyclic triterpenes was analysed using a ‘Royal Gala’ x ‘Granny Smith’ segregating population in 2013 and 2015, using apple peels extracted from mature fruit at harvest and after 12 weeks of cold storage. In 2013, 20 compound isoforms from nine unique compound classes were measured for both treatments. In 2015, 20 and 17 compound isoforms from eight unique compound classes were measured at harvest and after cold storage, respectively. In total, 68 quantitative trait loci (QTLs) were detected on 13 linkage groups (LG). Thirty two and 36 QTLs were detected for compounds measured at harvest and after cold storage, respectively. The apple chromosomes with the most QTLs were LG3, LG5, LG9 and LG17. The largest effect QTL was for trihydroxy-urs-12-ene-28-oic acid, located on LG5; this was measured in 2015 after storage, and was inherited from the ‘Royal Gala’ parent (24.9% of the phenotypic variation explained).

Modulation of cell signaling pathways by Phyllanthus amarus and its major constituents: potential role in the prevention and treatment of inflammation and cancer

The causal and functional connection between inflammation and cancer has become a subject of much research interest. Modulation of cell signaling pathways, such as those involving mitogen activated protein kinases (MAPKs), nuclear factor kappa β (NF-κB), phosphatidylinositol 3-kinase and protein kinase B (PI3K/Akt), and Wnt, and their outcomes play a fundamental role in inflammation and cancer. Activation of these cell signaling pathways can lead to various aspects of cancer-related inflammation. Hence, compounds able to modulate inflammation-related molecular targets are sought after in anticancer drug development programs. In recent years, plant extracts and their metabolites have been documented with potential in the prevention and treatment of cancer and inflammatory ailments. Plants possessing anticancer and anti-inflammatory properties due to their bioactive constituents have been reported to modulate the molecular and cellular pathways which are related to inflammation and cancer. In this review we focus on the flavonoids (astragalin, kaempferol, quercetin, rutin), lignans (phyllanthin, hypophyllanthin, and niranthin), tannins (corilagin, geraniin, ellagic acid, gallic acid), and triterpenes (lupeol, oleanolic acid, ursolic acid) of Phyllanthus amarus, which exert various anticancer and anti-inflammatory activities via perturbation of the NF-κB, MAPKs, PI3K/Akt, and Wnt signaling networks. Understanding the underlying mechanisms involved may help future research to develop drug candidates for prevention and new treatment for cancer and inflammatory diseases.

Synthesis and Anticancer Activity of CDDO and CDDO-Me, Two Derivatives of Natural Triterpenoids

Triterpenoids are natural compounds synthesized by plants through cyclization of squalene, known for their weak anti-inflammatory activity. 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO), and its C28 modified derivative, methyl-ester (CDDO-Me, also known as bardoxolone methyl), are two synthetic derivatives of oleanolic acid, synthesized more than 20 years ago, in an attempt to enhance the anti-inflammatory behavior of the natural compound. These molecules have been extensively investigated for their strong ability to exert antiproliferative, antiangiogenic, and antimetastatic activities, and to induce apoptosis and differentiation in cancer cells. Here, we discuss the chemical properties of natural triterpenoids, the pathways of synthesis and the biological effects of CDDO and its derivative CDDO-Me. At nanomolar doses, CDDO and CDDO-Me have been shown to protect cells and tissues from oxidative stress by increasing the transcriptional activity of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2). At doses higher than 100 nM, CDDO and CDDO-Me are able to modulate the differentiation of a variety of cell types, both tumor cell lines or primary culture cell, while at micromolar doses these compounds exert an anticancer effect in multiple manners; by inducing extrinsic or intrinsic apoptotic pathways, or autophagic cell death, by inhibiting telomerase activity, by disrupting mitochondrial functions through Lon protease inhibition, and by blocking the deubiquitylating enzyme USP7. CDDO-Me demonstrated its efficacy as anticancer drugs in different mouse models, and versus several types of cancer. Several clinical trials have been started in humans for evaluating CDDO-Me efficacy as anticancer and anti-inflammatory drug; despite promising results, significant increase in heart failure events represented an obstacle for the clinical use of CDDO-Me.

Plant triterpenoid saponins: biosynthesis, in vitro production, and pharmacological relevance

The saponins are a diverse class of natural products, with a broad scale distribution across different plant species. Chemically characterized as triterpenoid glycosides, they posses a 30C oxidosqualene precursor-based aglycone moiety (sapogenin), to which glycosyl residues are subsequently attached to yield the corresponding saponin. Based on the chemically distinct aglycone moieties, broadly, they are divided into triterpenoid saponins (dammaranes, ursanes, oleananes, lupanes, hopanes, etc.) and the sterol glycosides. This review aims to present in detail the biosynthesis patterns of the different aglycones from a common precursor and their glycosylation patterns to yield the functionally active glycoside. The review also presents recent advances in the pharmacological activities of these saponins, particularly as potent anti-neoplastic pharmacophores, antioxidants, or anti-viral/antibacterial agents. Since alternate production pedestals for these pharmacologically important triterpenes via cell and tissue cultures are an attractive option for their sustainable production, recent trends in the variety and scale of in vitro production of plant triterpenoids have also been discussed.

Supercritical Carbon Dioxide Antisolvent Fractionation for the Sustainable Concentration of Lavandula luisieri (Rozeira) Riv.- Mart Antimicrobial and Antioxidant Compounds and Comparison with Its Conventional Extracts

Lavandula stoechas subsp. luisieri is a Spanish subspecies from the Lamiaceae family. Its essential oil has been traditionally used for several medical applications though little is known about other extracts. Similar to many other studies aiming to obtain traditional plant extracts to be used in different applications, this work evaluated the antioxidant and antimicrobial activities of Lavandula luisieri extracts and the correlation with their composition. Traditional hydrodistillation and ethanolic maceration were used to obtain the essential oil and the maceration extract, respectively. A green and sustainable methodology was applied to the maceration extract that was under a Supercritical Antisolvent Fractionation process to obtain a fine solid enriched in rosmarinic acid and the terpenes oleanolic and ursolic acids. Antimicrobial activities of all extracts and pure identified compounds (rosmarinic and ursolic acids) were evaluated against five bacterial strains; Listeria monocytogenes, Enterococcus faecium, Staphylococcus aureus, Salmonella Typhimurium and Escherichia coli and were compared with the pure compounds identified, rosmarinic and ursolic acids. All strains were sensitive against L. luisieri essential oil. The solid product obtained from the supercritical process was concentrated in the identified actives compared to the maceration extract, which resulted in higher antimicrobial and DPPH scavenging activities. The supercritical sustainable process provided L. luisieri compounds, with retention of their antimicrobial and antioxidant activities, in a powder exemptof organic solvents with potential application in the clinical, food or cosmetic fields.

Oleanolic Acid Derivatives as Potential Inhibitors of HIV-1 Protease

Pentacyclic triterpenes, such as oleanolic acid (I), are promising scaffolds for diversification through the use of combinatorial methods to obtain derivatives that improve their biological properties, increasing their bioavailability and enhancing their therapeutic efficacy. The purpose of this study was to evaluate the influence that derivatives of oleanolic acid, conjugated with one or two amino acids and an acyl group, might exert on HIV-1 protease inhibition. The in vitro studies conducted suggested that the presence of a carboxyacyl group generally improves the inhibition of HIV-1 protease, especially when a phthaloyl group is present, with IC₅₀ concentration values below 5 μM. The gain in activity of three 3-phthaloyl derivatives, with sub-micromolar IC₅₀ values, was between 60- and 100-fold more active than oleanolic acid. A molecular docking study has also been performed to elucidate the mode of binding to the protease by these oleanolic acid derivatives. In general, the derivatives that exhibited the highest inhibitory activity of HIV-1 protease also showed the highest binding energies in docking simulations. The overall results suggest that the coupling of one or two amino acids and a phthaloyl group to oleanolic acid improves HIV-1 protease inhibition, implying that these triterpene derivatives may be promising antiviral agents against HIV.

Novel Oleanolic and Maslinic Acid Derivatives as a Promising Treatment against Bacterial Biofilm in Nosocomial Infections: An in Vitro and in Vivo Study

Oleanolic acid (OA) and maslinic acid (MA) are pentacyclic triterpenic compounds that abound in industrial olive oil waste. These compounds have renowned antimicrobial properties and lack cytotoxicity in eukaryotic cells as well as resistance mechanisms in bacteria. Despite these advantages, their antimicrobial activity has only been tested in vitro, and derivatives improving this activity have not been reported. In this work, a set of 14 OA and MA C-28 amide derivatives have been synthesized. Two of these derivatives, MA-HDA and OA-HDA, increase the in vitro antimicrobial activity of the parent compounds while reducing their toxicity in most of the Gram-positive bacteria tested, including a methicillin-resistant Staphylococcus aureus-MRSA. MA-HDA also shows an enhanced in vivo efficacy in a Galleria mellonella invertebrate animal model of infection. A preliminary attempt to elucidate their mechanism of action revealed that these compounds are able to penetrate and damage the bacterial cell membrane. More significantly, their capacity to reduce antibiofilm formation in catheters has also been demonstrated in two sets of conditions: a static and a more challenged continuous-flow S. aureus biofilm.

Ursolic Acid Derivatives as Potential Agents Against Acanthamoeba Spp

The current chemotherapy of Acanthamoeba keratitis relies on few drugs with low potential and limited efficacy, for all this there is an urgent need to identify new classes of anti-Acanthamoeba agents. In this regard, natural products play an important role in overcoming the current need and medicinal chemistry of natural products represents an attractive approach for the discovery and development of new agents. Ursolic acid, a natural pentacyclic triterpenoid compound, possesses a broad spectrum of activities including anti-Acanthamoeba. Herein, we report on the development by chemical transformation of an ursolic acid-based series of seven compounds (2-8), one of them reported for the first time. The structure-activity relationship (SAR) analysis of their anti-Acanthamoeba activity revealed that acylation/ether formation or oxidation enhances their biological profile, suggesting that the hydrophobic moiety contributes to activity, presumably by increasing the affinity and/or cell membrane permeability. These ursolic acid derivatives highlight the potential of this source as a good base for the development of novel therapeutic agents against Acanthamoeba infections.

Antimicrobial activity of the lupane triterpene 3β,6β,16β-trihydroxylup-20(29)-ene isolated from Combretum leprosum Mart

Introduction. Combretum leprosum (Combretaceae) is commonly found in the Northeast Region of Brazil and is known for several bioactivities, including antimicrobial ones. Because of increasing bacterial antibiotic resistance, natural products from several plants have been studied as putative adjuvants to antibiotic activity, including products from C. leprosum. Aims. This study was carried out to investigate the structural properties, bactericidal activity and antibiotic modifying action of the lupane triterpene 3β,6β,16β-trihydroxylup-20(29)-ene (CLF1) isolated from C. leprosum Mart. leaves.Methods. The CLF1 was evaluated by the Fourier transform infrared spectroscopy method and the antibacterial activity of this compound was assayed alone and in association with antibiotics by microdilution assay.Results. Spectroscopic studies confirmed the molecular structure of the CLF1 and permitted assignment of the main infrared bands of this natural product. Microbiological assays showed that this lupane triterpene possesses antibacterial action with clinical relevance against Staphylococcus aureus. The CLF1 triterpene increased antimicrobial activity against the multidrug-resistant Escherichia coli 06 strain when associated with the antibiotics gentamicin and amikacin. Synergistic effects were observed against the S. aureus 10 strain in the presence of the CLF1 triterpene with the antibiotic gentamicin.Conclusion. In conclusion, the CLF1 compound may be useful in the development of antibacterial drugs against the aforementioned bacteria.

Ursolic Acid and Its Derivatives as Bioactive Agents

Non-communicable diseases (NCDs) such as cancer, diabetes, and chronic respiratory and cardiovascular diseases continue to be threatening and deadly to human kind. Resistance to and side effects of known drugs for treatment further increase the threat, while at the same time leaving scientists to search for alternative sources from nature, especially from plants. Pentacyclic triterpenoids (PT) from medicinal plants have been identified as one class of secondary metabolites that could play a critical role in the treatment and management of several NCDs. One of such PT is ursolic acid (UA, 3 β-hydroxy-urs-12-en-28-oic acid), which possesses important biological effects, including anti-inflammatory, anticancer, antidiabetic, antioxidant and antibacterial effects, but its bioavailability and solubility limits its clinical application. Mimusops caffra, Ilex paraguarieni, and Glechoma hederacea, have been reported as major sources of UA. The chemistry of UA has been studied extensively based on the literature, with modifications mostly having been made at positions C-3 (hydroxyl), C12-C13 (double bonds) and C-28 (carboxylic acid), leading to several UA derivatives (esters, amides, oxadiazole quinolone, etc.) with enhanced potency, bioavailability and water solubility. This article comprehensively reviews the information that has become available over the last decade with respect to the sources, chemistry, biological potency and clinical trials of UA and its derivatives as potential therapeutic agents, with a focus on addressing NCDs.

In Vitro Cytotoxicity of Oleanolic/Ursolic Acids-Loaded in PLGA Nanoparticles in Different Cell Lines

Oleanolic (OA) and ursolic (UA) acids are recognized triterpenoids with anti-cancer properties, showing cell-specific activity that can be enhanced when loaded into polymeric nanoparticles. The cytotoxic activity of OA and UA was assessed by Alamar Blue assay in three different cell lines, i.e., HepG2 (Human hepatoma cell line), Caco-2 (Human epithelial colorectal adenocarcinoma cell line) and Y-79 (Human retinoblastoma cell line). The natural and synthetic mixtures of these compounds were tested as free and loaded in polymeric nanoparticles in a concentration range from 2 to 32 µmol/L. The highest tested concentrations of the free triterpene mixtures produced statistically significant cell viability reduction in HepG2 and Caco-2 cells, compared to the control (untreated cells). When loaded in the developed PLGA nanoparticles, no differences were recorded for the tested concentrations in the same cell lines. However, in the Y-79 cell line, a decrease on cell viability was observed when testing the lowest concentration of both free triterpene mixtures, and after their loading into PLGA nanoparticles.

Analyzing hedyotis diffusa mechanisms of action from the genomics perspective

BACKGROUND AND OBJECTIVE

Hedyotis diffusa is an herb used for anti-cancer, anti-oxidant, anti-inflammatory, and anti-fibroblast treatment in the clinical practice of Traditional Chinese Medicine. However, its pharmacological mechanisms have not been fully established and there is a lack of modern scientific verification. One of the best ways to further understand Hedyotis diffusa's mechanisms of action is to analyze it from the genomics perspective.

METHODS

In this study, we used network pharmacology approaches to infer the herb-gene interactions, the herb-pathway interactions, and the gene families. We then analyzed Hedyotis diffusa's mechanisms of action using the genomics context combined with the Traditional Chinese Medicine clinical practice and the pharmacological research.

RESULTS

The results obtained in the pathway and gene family analysis were consistent with the Traditional Chinese Medicine clinical experience and the pharmacological activities of Hedyotis diffusa.

CONCLUSIONS

Our approach can identify related genes and pathways correctly with little a priori knowledge, and provide potential directions to facilitate further research.

Ursolic acid and carvacrol may be potential inhibitors of dormancy protein small heat shock protein16.3 of Mycobacterium tuberculosis

Small heat shock protein16.3 (sHSP16.3) is a crucial protein for survival of Mycobacterium tuberculosis (MTB) in its host. Besides, this protein acts as a molecular chaperone during stress and is indispensable for MTB's growth, virulence and cell-wall thickening. sHSP16.3 is also a promising candidate for vaccine, serodiagnosis and drug design as well. In the present study, we have targeted sHSP16.3 with two phytochemicals, namely ursolic acid and carvacrol using in silico approach. Molecular docking analysis showed that both phytochemicals (ursolic acid and carvacrol) have docked with sHSP16.3 and shown tendency to inhibit the function of this vital protein of MTB. In addition, both compounds have exhibited strong compatibility with sHSP16.3 during whole 60 ns duration of molecular dynamics simulation. Further, the molecular mechanic/generalized Born/Poisson-Boltzmann surface area (MM/G/P/BSA) free energies were calculated which showed that both phytocompounds have stable and favourable binding energies causing strong binding with binding site of sHSP16.3. Taking together, the data of present study suggest that both phytocompounds may be potential inhibitor of sHSP16.3 of MTB and a best alternative to standard anti-tuberculosis drugs.