A systematic review of pentacyclic triterpenes and their derivatives as chemotherapeutic agents against tropical parasitic diseases

Function-Oriented Synthesis of Pentacyclic Triterpenoids and Discovery of an ent-Estrane as a Natural Product-Inspired Androgen Receptor Antagonist

While pentacyclic triterpenoids have a rich history in chemistry and biology, the challenges associated with their asymmetric synthesis contribute to the current reality that medicinal exploration in the area is largely constrained to natural product derivatization. To address this deficiency, a function-oriented synthesis of pentacyclic triterpenoids was pursued. Overall, we report a divergent synthesis of 26-norgermanicol and 26-norlupeol and we have identified a new class of androgen receptor antagonist that is ∼6× more potent than lupeol.

Novel triterpenoid pyrones, phthalimides and phthalates are selectively cytotoxic in CCRF-CEM cancer cells - Synthesis, potency, and mitochondrial mechanism of action

A series of triterpenoid pyrones was synthesized and subsequently modified to introduce phthalimide or phthalate moieties into the triterpenoid skeleton. These compounds underwent in vitro cytotoxicity screening, revealing that a subset of six compounds exhibited potent activity, with IC50 values in the low micromolar range. Further biological evaluations, including Annexin V and propidium iodide staining experiment revealed, that all compounds induce selective apoptosis in cancer cells. Measurements of mitochondrial potential, cell cycle analysis, and the expression of pro- and anti-apoptotic proteins confirmed, that apoptosis was mediated via the mitochondrial pathway. These findings were further supported by cell cycle modulation and DNA/RNA synthesis studies, which indicated a significant increase in cell accumulation in the G0/G1 phase and a marked reduction in S-phase cells, alongside a substantial inhibition of DNA synthesis. The activation of caspase-3 and the cleavage of PARP, coupled with a decrease in the expression of Bcl-2 and Bcl-XL proteins, underscored the induction of apoptosis through the mitochondrial pathway. Given their high activity and pronounced effect on mitochondria function, trifluoromethyl pyrones 1f and 2f, and dihydrophthalimide 2h have been selected for further development.

In Vitro Anti-Toxoplasma Activity of Extracts Obtained from Tabebuia rosea and Tabebuia chrysantha: The Role of β-Amyrin

Toxoplasmosis is a parasitic disease caused by the protozoan Toxoplasma gondii that is highly prevalent worldwide. Although the infection is asymptomatic in immunocompetent individuals, it severely affects immunocompromised individuals, causing conditions such as encephalitis, myocarditis, or pneumonitis. The limited therapeutic efficacy of drugs currently used to treat toxoplasmosis has prompted the search for new therapeutic alternatives. The aim of this study was to determine the anti-Toxoplasma activity of extracts obtained from two species of the genus Tabebuia. Twenty-six extracts, 12 obtained from Tabebuia chrysantha and 14 from Tabebuia rosea, were evaluated by a colorimetric technique using the RH strain of T. gondii that expresses β-galactosidase. Additionally, the activity of the promising extracts and their active compounds was evaluated by flow cytometry. β-amyrin was isolated from the chloroform extract obtained from the leaves of T. rosea and displayed important anti-Toxoplasma activity. The results show that natural products are an important source of new molecules with considerable biological and/or pharmacological activity.

Plant In Vitro Culture Factories for Pentacyclic Triterpenoid Production

Pentacyclic triterpenoids are a diverse subclass of naturally occurring terpenes with various biological activities and applications. These compounds are broadly distributed in natural plant resources, but their low abundance and the slow growth cycle of plants pose challenges to their extraction and production. The biosynthesis of pentacyclic triterpenoids occurs through two main pathways, the mevalonic acid (MVA) pathway and the 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway, which involve several enzymes and modifications. Plant in vitro cultures, including elicited and hairy root cultures, have emerged as an effective and sustainable system for pentacyclic triterpenoid production, circumventing the limitations associated with natural plant resources. Bioreactor systems and controlling key parameters, such as media composition, temperature, light quality, and elicitor treatments, have been optimized to enhance the production and characterization of specific pentacyclic triterpenoids. These systems offer a promising bioprocessing tool for producing pentacyclic triterpenoids characterized by a low carbon footprint and a sustainable source of these compounds for various industrial applications.

Synthesis of methotrexate-betulonic acid hybrids and evaluation of their effect on artificial and Caco-2 cell membranes

An efficient protocol for the synthesis of novel methotrexate-betulonic acid hybrids with a (tert-butoxycarbonylamino)-3,6-dioxa-8-octanamine (Boc-DOOA) linkage has been developed. Reaction of N-(2-(2-(2-aminoethoxy)ethoxy)ethyl)-betulonamide with methotrexate resulted in a mixture of isomeric conjugates which were separated by column chromatography. Their structures and composition have been fully established by 1H NMR, 13C spectra, FAB mass spectrometry and elemental analysis. The identity of conjugates was confirmed by LC-MS data. Membranotropic properties of the new hybrids were assessed on the basis of their interactions with artificial lipid membranes by differential scanning calorimetry (DSC) method. The ability of the conjugates to penetrate Caco-2 cells is inferior to methotrexate. Probably, this is due to the increasing lipophilicity, the affinity of these hybrid molecules for the lipid bilayer increases, which is confirmed by experiments with artificial membranes.

Antiviral potency of lupane and oleanane alkynyl-derivatives against human cytomegalovirus and papillomavirus

A library of 18 structurally diverse semisynthetic lupane, oleanane, and ursane types triterpenoids, including C19- or C28-(1,2,3-triazolyl)- and aminomethylated derivatives obtained by the «click» reaction with various aromatic and sugar azides or by Mannich reaction with secondary amines, were tested for antiviral activity against HCMV, HSV-1, and HPV-11 types. C28-Triazolyl-derivative with a benzyl substituent of 2,3-indolo-oleanolic acid was the most active against the HCMV virus with EC50 < 0.05 (SI > 81). Lupane 3,28-diacetoxy-triazolyl derivatives with phenyl- and fluorophenyl-fragments possess the highest activity among all screened compounds toward HPV-11 type virus with EC50 values of 2.97 µM and 1.20 μM, SI90 values of 28 and >125, respectively. One can see that modification of triterpenic alkynes to Mannich bases was more efficient in increasing an activity against HSV-1 than their conversion to triazoles.

Enhanced Cytotoxicity and Antimelanoma Activity of Novel Semisynthetic Derivatives of Betulinic Acid with Indole Conjugation

The prevalence and severity of skin cancer, specifically malignant melanoma, among Caucasians remains a significant concern. Natural compounds from plants have long been explored as potential anticancer agents. Betulinic acid (BI) has shown promise in its therapeutic properties, including its anticancer effects. However, its limited bioavailability has hindered its medicinal applications. To address this issue, two recently synthesized semisynthetic derivatives, N-(2,3-indolo-betulinoyl)diglycylglycine (BA1) and N-(2,3-indolo-betulinoyl)glycylglycine (BA2), were compared with previously reported compounds N-(2,3-indolo-betulinoyl)glycine (BA3), 2,3-indolo-betulinic acid (BA4), and BI. These compounds were evaluated for their effects on murine melanoma cells (B164A5) using various in vitro assays. The introduction of an indole framework at the C2 position of BI resulted in an increased cytotoxicity. Furthermore, the cytotoxicity of compound BA4 was enhanced by conjugating its carboxylic group with an amino acid residue. BA2 and BA3, with glycine and glycylglycine residues at C28, exhibited approximately 2.20-fold higher inhibitory activity compared to BA4. The safety assessment of the compounds on human keratinocytes (HaCaT) has revealed that concentrations up to 10 µM slightly reduced cell viability, while concentrations of 75 µM resulted in lower cell viability rates. LDH leakage assays confirmed cell membrane damage in B164A5 cells when exposed to the tested compounds. BA2 and BA3 exhibited the highest LDH release, indicating their strong cytotoxicity. The NR assay revealed dose-dependent lysosome disruption for BI and 2,3-indolo-betulinic acid derivatives, with BA1, BA2, and BA3 showing the most cytotoxic effects. Scratch assays demonstrated concentration-dependent inhibition of cell migration, with BA2 and BA3 being the most effective. Hoechst 3342 staining revealed that BA2 induced apoptosis, while BA3 induced necrosis at lower concentrations, confirming their anti-melanoma properties. In conclusion, the semisynthetic derivatives of BI, particularly BA2 and BA3, show promise as potential candidates for further research in developing effective anti-cancer therapies.

Synergistic antileishmanial activity of erythrodiol, uvaol, and oleanolic acid isolated from olive leaves of cv. Chemlali

This study aimed to assess the antileishmanial activity of biomolecules obtained from Olea europaea L. leaves and twigs recovered from eight Tunisian cultivars. The extraction was first carried out with 80% methanol, and then the obtained extract was fractionated using three solvents of increasing polarity: cyclohexane (CHX), dichloromethane (DCM) and ethyl acetate (EtOAc). The antileishmanial activity was determined against leishmanial strains responsible for cutaneous, visceral, and mucocutaneous leishmaniasis. The cyclohexane fraction of the leaves of cv. Chemlali from the region of Sidi-Bouzid exhibited the strongest leishmanicidal activity against all the tested leishmanial strains. The inhibition concentrations (IC50) were 16.5, 14.5, and 7.4 μg mL-1 for Leishmania mexicana (cutaneous), Leishmania braziliensis (mucocutaneous), and Leishmania donovani (visceral), respectively. Interestingly, low cytotoxicity was observed on THP-1 cells with selective indexes (SI) ranging from 22.8 to 50.5. HPLC-HRMS and full-house NMR analysis allowed the identification of three triterpenic compounds, oleanolic acid (IC50 = 64.1 μg mL-1), erythrodiol (IC50 = 52.0 µg mL-1), and uvaol (IC50 = 53.8 μg mL-1). Antileishmanial activity of uvaol and oleanolic acid has been previously reported. However, this work constitutes the first report of the antileishmanial activity of erythrodiol which showed combinatorial interaction with uvaol (IC50 = 26.1 μg mL-1) against Leishmania tropica. The mixture of the three compounds, as major ones, exhibited an enhanced activity against Leishmania tropica (IC50 = 16.3 µg mL-1) compared to erythrodiol alone or the combination of uvaol and erythrodiol. This finding is of great importance and needs further investigation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03825-3.

Lupeol Acetate and α-Amyrin Terpenes Activity against Trypanosoma cruzi: Insights into Toxicity and Potential Mechanisms of Action

BACKGROUND

Chagas disease is a potentially fatal disease caused by the parasite Trypanosoma cruzi. There is growing scientific interest in finding new and better therapeutic alternatives for this disease's treatment.

METHODS

A total of 81 terpene compounds with potential trypanocidal activity were screened and found to have potential T. cruzi cysteine synthase (TcCS) inhibition using molecular docking, molecular dynamics, ADME and PAIN property analyses and in vitro susceptibility assays.

RESULTS

Molecular docking analyses revealed energy ranges from -10.5 to -4.9 kcal/mol in the 81 tested compounds, where pentacyclic triterpenes were the best. Six compounds were selected to assess the stability of the TcCS-ligand complexes, of which lupeol acetate (ACLUPE) and α-amyrin (AMIR) exhibited the highest stability during 200 ns of molecular dynamics analysis. Such stability was primarily due to their hydrophobic interactions with the amino acids located in the enzyme's active site. In addition, ACLUPE and AMIR exhibited lipophilic characteristics, low intestinal absorption and no structural interferences or toxicity. Finally, selective index for ACLUPE was >5.94, with moderate potency in the trypomastigote stage (EC₅₀ = 15.82 ± 3.7 μg/mL). AMIR's selective index was >9.36 and it was moderately potent in the amastigote stage (IC₅₀ = 9.08 ± 23.85 μg/mL).

CONCLUSIONS

The present study proposes a rational approach for exploring lupeol acetate and α-amyrin terpene compounds to design new drugs candidates for Chagas disease.

Selected plant triterpenoids and their amide derivatives in cancer treatment: A review

Medicinal plants have been used to treat different diseases throughout the human history namely in traditional medicine. Most of the plants mentioned in this review article belong among them, including those that are widely spread in the nature, counted frequently to be food and nutrition plants and producing pharmacologically important secondary metabolites. Triterpenoids represent an important group of plant secondary metabolites displaying emerging pharmacological importance. This review article sheds light on four selected triterpenoids, oleanolic, ursolic, betulinic and platanic acid, and on their amide derivatives as important natural or semisynthetic agents in cancer treatment, and, in part, in pathogenic microbe treatment. A literature search was made in the Web of Science for the given key words covering the required area of secondary plant metabolites and their amide derivatives. The most recently published findings on the biological activity of the selected triterpenoids, and on the structures and biological activity of their relevant amide derivatives have been summarized therein. Mainly anti-cancer effects, and, in part, antimicrobial and other effects of the four selected triterpenoids and their amide derivatives have also been reviewed. A comparison of the effects of the parent plant products and those of their amide derivatives has been made.

Semisynthetic triterpenes led to the generation of selective antitrypanosomal lead compounds

Triterpenes α,β-amyrin are naturally occurring molecules that can serve as building blocks for synthesizing new chemical entities. This study synthesized acyl, carboxyesther, NSAID, and nitrogenous derivatives and evaluated their antimicrobial activity. A cyclodextrin complexation method was developed to improve the solubility of the derivatives. Of the 17 derivatives tested, five exhibited activity against Trypanosoma cruzi, T. brucei, Leishmania infantum, Candida albicans, Staphylococcus aureus, and Escherichia coli. The 9a/9b mixture showed weak activity against the parasites (IC₅₀ 24.45-40.32 μM). However, it showed no activity for the other microorganisms. Derivatives 14a/14b exhibited potent activity against T. cruzi (IC₅₀ 2.0 nM) in this tested concentration did not show activity to the other microorganisms and were not cytotoxic. Derivatives 15a/15b and 16a/16b demonstrated relevant activity against the parasites (IC₅₀ 2.24-5.44 μM), but were also cytotoxic. Derivatives 17a/17b showed low activity against the tested parasites (IC₅₀ 21.70-22.79 μM), but they were selective since they did not show activity against other microorganisms. In docking studies, in general, all derivatives showed complementarity with the CYP51 binding site of the trypanosomatid mainly by hydrophobic interactions; thus, it is not conclusive that the molecules act by inhibiting this enzyme. Our results showed that triterpenes derivatives with antitrypanosomal activity could be synthesized by an inexpensive and rapid method.

Cytotoxic and antileishmanial triterpenes of Tabebuia aurea (Silva Manso) leaves

The bioactivity-guided fractionation of the total ethanolic extract of the leaves of Tabebuia aurea revealed the cytotoxic and antileishmanial potency of the ethyl acetate fraction, in which its phytochemical investigation resulted in the isolation of five triterpenes; identified as oleanolic acid (1), ursolic acid (2), pomolic acid (3), tormentic acid (4), 3β,6β,19α-trihydroxy-urs-12-en-28-oic acid (5) in addition to one triterpenoid glucoside, spathodic acid 28-O-β-D-glucopyranoside (6). Whereas compound 1 showed cytotoxic activity against three different cell lines; A549, MCF-7 and HepG2 with IC₅₀ values of 31.7 ± 1.2, 27.4 ± 1.8 and 28.8 ± 1.1 μg/mL, respectively (etoposide as a positive control: 28.1 ± 4.2, 22.5 ± 4.5, and 20.4 ± 0.8 μg/mL, respectively), while compounds 1 and 2 showed antileishmanial activity with IC₅₀ values of 10.2 ± 0.9 μg/mL and 5.1 ± 0.4 μg/mL, respectively (miltefosine: 7.7 ± 2.1 μg/mL).

In vitro growth inhibitory effect of selected 18β-glycyrrhetinic acid esters on Theileriaannulata

Glycyrrhetinic acid (GA) is one of the important Pentacyclic Triterpenoids (PT) found in the roots of licorice. This study aimed to evaluate the in vitro growth inhibitory effect of 18β-GA (18β-Glycyrrhetinic acid) and C-30 esters against Theileria annulata, the causative agent of Tropical Bovine Theileriosis. C-30 esters of 18β-GA were synthesized and their structures were elucidated using spectroscopy. The pharmacodynamic properties of 18β-GA and its C-30 esters were predicted using DataWarrior and Swiss ADME tools. Cattle isolates of T. annulata schizont-infected bovine lymphoblastoid cells were cultured using standard conditions and the growth inhibitory effect of GA and its esters were evaluated using MTT assay. The isopropyl ester of 18β-GA (GI₅₀- 1.638 μM; R²- 0.818) showed improved anti-theileriosis efficacy than other 18β-GA derivatives. The propyl (GI₅₀ - 5.549 μM), ethyl (GI₅₀ - 5.638 μM), and benzyl (GI₅₀ - 7.431 μM) esters also showed considerable inhibitory effect. The GI₅₀ value for 18β-GA was recorded as 6.829 μM. This study throws light on the usefulness of 18β-GA and its esters for the treatment of Tropical Bovine Theileriosis.

Potential of Triterpenic Natural Compound Betulinic Acid for Neglected Tropical Diseases New Treatments

Neglected tropical diseases are one of the most important public health problems in many countries around the world. Among them are leishmaniasis, Chagas disease, and malaria, which contribute to more than 250 million infections worldwide. There is no validated vaccine to prevent these infections and the treatments available are obsolete, highly toxic, and non-effective due to parasitic drug resistance. Additionally, there is a high incidence of these diseases, and they may require hospitalization, which is expensive to the public health systems. Therefore, there is an urgent need to develop new treatments to improve the management of infected people, control the spread of resistant strains, and reduce health costs. Betulinic acid (BA) is a triterpene natural product which has shown antiparasitic activity against Leishmania, Trypanosoma cruzi, and Plasmodium. Here, we review the main results regarding the in vitro and in vivo pharmacological activity of BA and its derivatives against these parasites. Some chemical modifications of BA have been shown to improve its activities against the parasites. Further improvement on studies of drug-derived, as well as structure–activity relationship, are necessary for the development of new betulinic acid-based treatments.

Plant Terpenoids as Hit Compounds against Trypanosomiasis

Human African trypanosomiasis (sleeping sickness) and American trypanosomiasis (Chagas disease) are vector-borne neglected tropical diseases, caused by the protozoan parasites Trypanosoma brucei and Trypanosoma cruzi, respectively. These diseases were circumscribed to South American and African countries in the past. However, human migration, military interventions, and climate changes have had an important effect on their worldwide propagation, particularly Chagas disease. Currently, the treatment of trypanosomiasis is not ideal, becoming a challenge in poor populations with limited resources. Exploring natural products from higher plants remains a valuable approach to find new hits and enlarge the pipeline of new drugs against protozoal human infections. This review covers the recent studies (2016–2021) on plant terpenoids, and their semi-synthetic derivatives, which have shown promising in vitro and in vivo activities against Trypanosoma parasites.

Machine Learning Analysis of Essential Oils from Cuban Plants: Potential Activity against Protozoa Parasites

Essential oils (EOs) are a mixture of chemical compounds with a long history of use in food, cosmetics, perfumes, agricultural and pharmaceuticals industries. The main object of this study was to find chemical patterns between 45 EOs and antiprotozoal activity (antiplasmodial, antileishmanial and antitrypanosomal), using different machine learning algorithms. In the analyses, 45 samples of EOs were included, using unsupervised Self-Organizing Maps (SOM) and supervised Random Forest (RF) methodologies. In the generated map, the hit rate was higher than 70% and the results demonstrate that it is possible find chemical patterns using a supervised and unsupervised machine learning approach. A total of 20 compounds were identified (19 are terpenes and one sulfur-containing compound), which was compared with literature reports. These models can be used to investigate and screen for bioactivity of EOs that have antiprotozoal activity more effectively and with less time and financial cost.

Anti-Toxoplasma gondii effect of lupane-type triterpenes from the bark of black alder (Alnus glutinosa) and identification of a potential target by reverse docking

Toxoplasmosis is a worldwide parasitosis that is generally benign. The infestation may pose a risk to immunocompromized patients and to fetuses when pregnant women have recently seroconverted. Current treatments have numerous side effects and chemoresistance is emerging, hence the need to find new anti-Toxoplasma gondii substances. This study focuses on the antiparasitic potential of lupane-type pentacyclic triterpenes isolated from the bark of black alder (Alnus glutinosa), as well as the hypothesis of their macromolecular target by an original method of reverse docking. Among the isolated triterpenes, betulone was the most active compound with an IC50 of 2.7 ± 1.2 μM, a CC50 greater than 80 μM, and a selectivity index of over 29.6. An additional study of the anti-T. gondii potential of commercially available compounds (betulonic acid methyl ester and betulonic acid) showed the important role of the C3 ketone function and the C28 oxidation level on the lupane-type triterpene in the antiparasitic activity since their IC50 and CC50 were similar to that of betulone. Finally, the most active compounds were subjected to the AMIDE reverse docking workflow. A dataset of 87 T. gondii proteins from the Protein Data Bank was created. It identified calcium-dependent protein kinase CDPK3 as the most likely target of betulin derivatives.

A Validated HPLC-PDA-HRMS Method to Investigate the Biological Stability and Metabolism of Antiparasitic Triterpenic Esters

Pentacyclic triterpenes (PTs) are commonly found in medicinal plants with well-known antiparasitic effects. Previous research on C-3 and C-27 triterpenic esters showed effective and selective in vitro antiparasitic activities and in vivo effectiveness by parenteral routes. The aim of this study was to determine triterpenic esters' stability in different biological-like media and the main microsomal degradation products. An HPLC-PDA method was developed and validated to simultaneously analyze and quantify bioactive triterpenic esters in methanol (LOQ: 2.5 and 1.25-100 µg/mL) and plasma (LOQ: 5-125 µg/mL). Overall, both triterpenic esters showed a stable profile in aqueous and buffered solutions as well as in entire plasma, suggesting gaining access to the ester function is difficult for plasma enzymes. Conversely, after 1 h, 30% esters degradation in acidic media was observed with potential different hydrolysis mechanisms. C-3 (15 and 150 µM) and C-27 esters (150 µM) showed a relatively low hepatic microsomal metabolism (<23%) after 1 h, which was significantly higher in the lowest concentration of C-27 esters (15 µM) (>40% degradation). Metabolic HPLC-PDA-HRMS studies suggested hydrolysis, hydroxylation, dehydration, O-methylation, hydroxylation and/or the reduction of hydrolyzed derivatives, depending on the concentration and the position of the ester link. Further permeability and absorption studies are required to better define triterpenic esters pharmacokinetic and specific formulations designed to increase their oral bioavailability.

New quaternized pyridinium derivatives of betulin: Synthesis and evaluation of membranotropic properties on liposomes, pro- and eukaryotic cells, and isolated mitochondria

The present study describes the synthesis of pyridinium derivatives of betulin, including new 4-methyl- and 3,5-methyl-pyridinium analogs, their effect on artificial membrane systems (liposomes), cytotoxicity in models of prokaryotic (E. coli K-12 MG1655) and eukaryotic cells (rat thymocytes), as well as their effect on the functioning of membrane systems of rat liver mitochondria. We have shown that the presence of methyl groups in the pyridine ring of compounds determines the ability of the derivatives to effectively permeabilize the artificial membrane of lecithin liposomes for the fluorescent probe sulforhodamine B. The 4-methyl- and 3,5-methyl-pyridinium analogs inhibit the growth of E. coli K-12 MG1655 and, at the same time, did not have a cytotoxic effect on rat thymocytes. However, in the latter case, we noted a decrease in the mitochondrial potential of cells. The studied compounds reduced the functional activity of mitochondria, suppressing the activity of complexes of the respiratory chain and reducing the membrane potential. In addition, compounds containing methyl groups in the p- and m-positions of the pyridine ring were also able to permeabilize the inner membrane of mitochondria, causing them to swell. In this case, the most lipophilic compound containing two methyl substituents at the m-position of the pyridine fragment was most effective and had a protonophore effect on mitochondria. The paper discusses the dependence of the membranotropic and biological actions of the quaternized pyridine derivatives of betulin on their structure and lipophilicity.

Investigation of antiparasitic activity of ten European tree bark extracts on Toxoplasma gondii and bioguided identification of triterpenes in Alnus glutinosa barks

Toxoplasmosis is a worldwide parasitosis that affects one-third of the population. People at risk, such as immunocompromised patients (AIDS, chemotherapy treatment) or fetuses (maternal-fetal transmission) can develop severe forms of the disease. The antiparasitic activity of extracts of different polarities (n-heptane, MeOH, MeOH/H₂O) of 10 tree species endemic to temperate regions was investigated against Toxoplasma gondii infection in vitro. Our results showed that the n-heptane extract of the black alder (Alnus glutinosa) exhibited a significant antiparasitic activity without any cytotoxicity at the tested concentrations, with an IC₅₀ of up to 25.08 μg/mL and a selectivity index higher than 3.99. The chemical profiling of this extract revealed triterpenes as major constituents. The ability of commercially available triterpene (betulin, betulinic acid, and betulone) to inhibit the growth of T. gondii was evaluated and showed growth inhibition rates of 44%, 49%, and 99% at 10 μM, respectively.

Synthesis and Biological Evaluation of C-17-Amino-Substituted Pyrazole-Fused Betulinic Acid Derivatives as Novel Agents for Osteoarthritis Treatment

A series of pyrazole-fused betulinic acid (BA) derivatives were designed and synthesized by replacing the carboxyl group at C-17 with aliphatic amine, amide, and urea groups. The suppressive effects of the compounds on osteoclast (OC) formation and inflammatory cytokine production were evaluated on murine macrophages, RAW264.7 cells, conditioned with receptor activator for nuclear factor-κB ligand (RANKL)/macrophage colony stimulating factor (M-CSF) or lipopolysaccharide (LPS), respectively. Results showed that, compared with betulinic acid, most of these compounds exhibited significant improvements in inhibitory potency. Compound 25 exhibited distinguished activities on inhibiting OC differentiation with an IC50 value of 1.86 μM. Meanwhile, compound 25, displaying the most promising suppression on IL-1β secretion from RAW264.7 cells, was further found to possess therapeutic effects in the sodium monoiodoacetate (MIA)-induced osteoarthritis rat model. Dose-dependent benefits were observed in MIA-elicited rats with ameliorated joint pain as well as decreased cartilage damage and bone changes after compound 25 treatment.

Design, Synthesis and Biological Activity of C3 Hemisynthetic Triterpenic Esters as Novel Antitrypanosomal Hits

Research for innovative drugs is crucial to contribute to parasitic infections control and eradication. Inspired by natural antiprotozoal triterpenes, a library of 12 hemisynthetic 3-O-arylalkyl esters was derived from ursolic and oleanolic acids through one-step synthesis. Compounds were tested on Trypanosoma, Leishmania and the WI38 cell line alongside with a set of triterpenic acids. Results showed that the triterpenic C3 esterification keeps the antitrypanosomal activity (IC50 ≈1.6-5.5 μm) while reducing the cytotoxicity compared to parent acids. Unsaturation of the ester alkyl chain leads to an activity loss interestingly kept when a sterically hindered group replaces the double bond or shields the ester group. An ursane/oleanane C3 hydroxylation was the only important feature for antileishmanial activity. Two candidates, dihydrocinnamoyl and 2-fluorophenylpropionyl ursolic acids, were tested on an acute mouse model of African trypanosomiasis with significant parasitemia reduction at day 5 post-infection for the dihydrocinnamoyl derivative. Further evaluation on other alkyl/protective groups should be investigated both in vitro and in vivo.

Substituted dienes prepared from betulinic acid - Synthesis, cytotoxicity, mechanism of action, and pharmacological parameters

A set of new substituted dienes were synthesized from betulinic acid by its oxidation to 30-oxobetulinic acid followed by the Wittig reaction. Cytotoxicity of all compounds was tested in vitro in eight cancer cell lines and two noncancer fibroblasts. Almost all dienes were more cytotoxic than betulinic acid. Compounds 4.22, 4.30, 4.33, 4.39 had IC₅₀ below 5 μmol/L; 4.22 and 4.39 were selected for studies of the mechanism of action. Cell cycle analysis revealed an increase in the number of apoptotic cells at 5 × IC₅₀ concentration, where activation of irreversible changes leading to cell death can be expected. Both 4.22 and 4.39 led to the accumulation of cells in the G0/G1 phase with partial inhibition of DNA/RNA synthesis at 1 × IC₅₀ and almost complete inhibition at 5 × IC₅₀. Interestingly, compound 4.39 at 5 × IC₅₀ caused the accumulation of cells in the S phase. Higher concentrations of tested drugs probably inhibit more off-targets than lower concentrations. Mechanisms disrupting cellular metabolism can induce the accumulation of cells in the S phase. Both compounds 4.22 and 4.39 trigger selective apoptosis in cancer cells via intrinsic pathway, which we have demonstrated by changes in the expression of the crucial apoptosis-related protein. Pharmacological parameters of derivative 4.22 were superior to 4.39, therefore 4.22 was the finally selected candidate for the development of anticancer drug.

Ursolic and betulinic semisynthetic derivatives show activity against CQ-resistant Plasmodium falciparum isolated from Amazonia

ACT's low levels of Plasmodium parasitemia clearance are worrisome since it is the last treatment option against P. falciparum. This scenario has led to investigations of compounds with different mechanisms of action for malaria treatment. Natural compounds like ursolic acid (UA) and betulinic acid (BA), distinguished by their activity against numerous microorganisms, including P. falciparum, have become relevant. This study evaluated the antiplasmodial activity of imidazole derivatives of UA and BA against P. falciparum in vitro. Eight molecules were obtained by semisynthesis and tested against P. falciparum strains (NF54 and CQ-resistant 106/cand isolated in Porto Velho, Brazil); 2a and 2b showed activity against NF54 and 106/cand strains with IC50  < 10 µM. They presented high selectivity indexes (SI > 25) and showed synergism when combined with artemisinin. 2b inhibited the parasite's ring and schizont forms regardless of when the treatment began. In silico analysis presented a tight bind of 2b in the topoisomerase II-DNA complex. This study demonstrates the importance of natural derivate compounds as new candidates for malarial treatment with new mechanisms of action. Semisynthesis led to new triterpenes that are active against P. falciparum and may represent new alternatives for malaria drug development.

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.

Multi-omics approaches to improve malaria therapy

Malaria contributes to the most widespread infectious diseases worldwide. Even though current drugs are commercially available, the ever-increasing drug resistance problem by malaria parasites poses new challenges in malaria therapy. Hence, searching for efficient therapeutic strategies is of high priority in malaria control. In recent years, multi-omics technologies have been extensively applied to provide a more holistic view of functional principles and dynamics of biological mechanisms. We briefly review multi-omics technologies and focus on recent malaria progress conducted with the help of various omics methods. Then, we present up-to-date advances for multi-omics approaches in malaria. Next, we describe resistance phenomena to established antimalarial drugs and underlying mechanisms. Finally, we provide insight into novel multi-omics approaches, new drugs and vaccine developments and analyze current gaps in multi-omics research. Although multi-omics approaches have been successfully used in malaria studies, they are still limited. Many gaps need to be filled to bridge the gap between basic research and treatment of malaria patients. Multi-omics approaches will foster a better understanding of the molecular mechanisms of Plasmodium that are essential for the development of novel drugs and vaccines to fight this disastrous disease.

Calendula officinalis Triterpenoid Saponins Impact the Immune Recognition of Proteins in Parasitic Nematodes

The influence of triterpenoid saponins on subcellular morphological changes in the cells of parasitic nematodes remains poorly understood. Our study examines the effect of oleanolic acid glucuronides from marigold (Calendula officinalis) on the possible modification of immunogenic proteins from infective Heligmosomoides polygyrus bakeri larvae (L3). Our findings indicate that the triterpenoid saponins alter the subcellular morphology of the larvae and prevent recognition of nematode-specific proteins by rabbit immune-IgG. TEM ultrastructure and HPLC analysis showed that microtubule and cytoskeleton fibres were fragmented by saponin treatment. MASCOT bioinformatic analysis revealed that in larvae exposed to saponins, the immune epitopes of their proteins altered. Several mitochondrial and cytoskeleton proteins involved in signalling and cellular processes were downregulated or degraded. As possible candidates, the following set of recognised proteins may play a key role in the immunogenicity of larvae: beta-tubulin isotype, alpha-tubulin, myosin, paramyosin isoform-1, actin, disorganized muscle protein-1, ATP-synthase, beta subunit, carboxyl transferase domain protein, glutamate dehydrogenase, enolase (phosphopyruvate hydratase), fructose-bisphosphate aldolase 2, tropomyosin, arginine kinase or putative chaperone protein DnaK, and galactoside-binding lectin. Data are available via ProteomeXchange with identifier PXD024205.

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.

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.

Biotransformation of Oleanane and Ursane Triterpenic Acids

Oleanane and ursane pentacyclic triterpenoids are secondary metabolites of plants found in various climatic zones and regions. This group of compounds is highly attractive due to their diverse biological properties and possible use as intermediates in the synthesis of new pharmacologically promising substances. By now, their antiviral, anti-inflammatory, antimicrobial, antitumor, and other activities have been confirmed. In the last decade, methods of microbial synthesis of these compounds and their further biotransformation using microorganisms are gaining much popularity. The present review provides clear evidence that industrial microbiology can be a promising way to obtain valuable pharmacologically active compounds in environmentally friendly conditions without processing huge amounts of plant biomass and using hazardous and expensive chemicals. This review summarizes data on distribution, microbial synthesis, and biological activities of native oleanane and ursane triterpenoids. Much emphasis is put on the processes of microbial transformation of selected oleanane and ursane pentacyclic triterpenoids and on the bioactivity assessment of the obtained derivatives.

In-silico studies on Myo inositol-1-phosphate synthase of Leishmania donovani in search of anti-leishmaniasis

Myo-inositol is one of the vital nutritional requirements for the Leishmania parasites' survival and virulence in the mammalian host. . Myo-inositol-1-phosphate synthase (MIPS) is responsible for the synthesis of myo-inositol in Leishmania, which plays a vital role in Leishmania's virulence to mammalian hosts. Earlier studies suggest MIP synthase as a potential drug target against which valproate was used as a drug. So, MIP synthase can be used as a target for anti-leishmanial drugs, and its inhibition may help in preventing leishmaniasis. The present study aims to identify valproate's potent analogs as drugs against MIP synthase of L. donovani (Ld-MIPS) with minimum side effects and toxicity to host.In this study, the three-dimensional structure of Ld-MIPS was built, followed by active site prediction. Ligand-based virtual screening was done using hybrid similarity recognition methods. The best 123 valproate analogs were filtered based on their quantitative structure activity relationship (QSAR) properties and were docked against Ld-MIPS using FlexX, PyRx and iGEMDOCK software. The topmost five ligands were selected for molecular dynamics simulation and pharmacokinetic analysis based on the docking score. Simulation studies up to 30 ns revealed that all five lead molecules bound with Ld-MIPS throughout MD simulation and there was no variation in their backbone. All the chosen inhibitors exhibited good pharmacokinetics/ADMET predictions with an excellent absorption profile, metabolism, oral bioavailability, solubility, excretion, and minimal toxicity, suggesting that these inhibitors may further be developed as anti-leishmaniasis drugs to prevent the spread of leishmaniasis.Communicated by Ramaswamy H. Sarma.

Barcode sequence could be a good target for developing a species-specific anti-parasite agent based on CRISPR-Cas9

Parasitic infections are a severe issue in many regions of the world. We assume that if a chemical can destroy a DNA barcode sequence, then this chemical could be developed as a species-specific parasiticidal agent. To test this hypothesis, we designed sgRNAs that target the sequences of both a DNA barcode (ITS-2) and a control (5.8S rDNA) in Cryptocaryon irritans. In in vivo tests, we found that exposure to Cas9 mRNA mixed with sgRNAs was able to significantly reduce the hatching rate of tomont and the survival rate of theront. Quantitative Real-time PCR demonstrated that the DNAs of tomont and theront exposed to sgRNAs and Cas9 mRNA were significantly disrupted, no matter whether they were exposed to a single sgRNA or a mixture of two sgRNAs. DNA sequencing also suggested the test group that was exposed to a single sgRNA mixed with Cas9-induced mutation at sgRNA targeted fragments and the test group exposed to two sgRNAs combined with Cas9-induced deletion of large pieces. The findings and principles provided by this study contribute to the development of novel nucleic acid therapeutic drugs for cryptocaryoniasis and other parasitic diseases and provide insight into the development of species-specific parasiticidal agents.

The Novel Synthetic Triterpene Methyl 3β-O-[4-(2-Aminoethylamino)-4-oxo-butyryl]olean-12-ene-28-oate Inhibits Breast Tumor Cell Growth in Vitro and in Vivo

Oleanolic and ursolic acids were used as lead compounds to synthesize a series of pentacyclic triterpenoid derivatives bearing ethylenediamine, butanediamine, or hexanediamine groups at the C-3 position. The potential antiproliferative activity of these compounds was examined in A549 (human non-small cell lung cancer cells), MCF-7 (human breast cancer cells), and HeLa (human cervical carcinoma cells) cells. Methyl 3β-O-[4-(2-aminoethylamino)-4-oxo-butyryl]olean-12-ene-28-oate (DABO-Me) was identified as a promising antiproliferative agent in vitro and in vivo. DABO-Me strongly suppressed the proliferation of A549, MCF-7, and HeLa cells (IC50 = 4-7 µM). In MCF-7 cells, DABO-Me upregulated the pro-apoptotic protein Bax, downregulated the anti-apoptotic protein Bcl-2, promoted the release of cytochrome c, and activated caspase-3/9. Transwell and flow cytometry assays showed that DABO-Me inhibited MCF-7 cell proliferation, migration, and invasion, and induced apoptosis and S phase arrest. In vitro and in vivo experiments indicated that DABO-Me inhibited MCF-7 cell proliferation and suppressed tumor growth. Taken together, these results indicate that DABO-Me could be developed as an effective antitumor drug.

Design and synthesis of pentacyclic triterpene conjugates and their use in medicinal research

Triterpenoids are natural products from plants and many other organisms that have various biological activities, such as antitumor, antiviral, antimicrobial, and protective activities. This review covers the synthesis and biological evaluation of pentacyclic triterpene (PT) conjugates with other molecules that have been found to increase the IC₅₀ or improve the pharmacological profile of the parent PT. Some of these molecules are designed to target specific proteins or cellular organelles, which has resulted in highly selective lead structures for drug development. Other PT conjugates are useful for investigating their mechanism of action. This concept has been very successful: 1) Many compounds, especially mitochondria-targeting PT conjugates, have reached a selective cytotoxicity at low nanomolar concentrations in cancer cells. 2) A number of PT conjugates have had high activity against HIV or the influenza virus. 3) Fluorescent PT conjugates have been able to visualize the PT in living cells, which has allowed quantification of the uptake and distribution of the PT within the cell. 4) Biotinylated PT conjugates have been used to identify target proteins, which may help to show their mechanism of action. 5) A large number of PT conjugates with polyethylene glycol (PEG), polyamines, etc. form nanometer-sized micelles that have a much better pharmacological profile than the PT alone. In summary, the connection of a PT to an appropriate modifying molecule has resulted in extremely useful semisynthetic compounds with a high potential to treat cancer or viral infections or compounds that are useful for the study of the mechanism of action of PTs at the molecular level.

Analysis of knowledge and attitudes related to parasitic infections among inhabitants of Ahvaz County, Khuzestan Province, Iran

Parasitic diseases are among the major health problems of various societies, especially people in developing countries, causing high economic and mortality burdens. Many researchers have reported that awareness and knowledge of a disease are effective in preventing and controlling the disease. The aim of the present study was to assess the knowledge and attitudes on parasitic diseases of the population in Ahvaz County, southwestern Iran. This community-based cross-sectional study was carried out in 2017 on 3500 subjects above 15 years old of Ahvaz County. First, participants were provided the necessary information regarding the study, and then data were collected using a constructed questionnaire. Of the 3500 participants, 1732 (49.5%) were female and 1768 (50.5%) were male, 348 (9.9%) said that they had been infected with a parasitic disease at least once in their lifetime. Almost half of the participants (42.8%) knew malaria was a parasitic disease and 50.2%, 48.9%, and 41.5% were aware of the possible transmission of parasitic diseases through uncooked meat, dirty hands, and close contact with animals. Regarding clinical symptoms, 73.2% and 32.6% of the respondents knew diarrhea and abdominal pain respectively were clinical symptoms of intestinal parasitic diseases. However, only 31.3% were aware of the close contact with cats and the risk of human toxoplasmosis and possible abortion in pregnant women. The findings reveal that the attitude of most participants toward treatment was positive (93.9%), but only 47.5% of believed that disinfecting fruits and vegetables could prevent intestinal parasitic infections.

Trypanostatic activity of geranylacetone: Mitigation of Trypanosoma congolense-associated pathological pertubations and insight into the mechanism of anaemia amelioration using in vitro and in silico models

Trypanosoma congolense is an important pathogen that wreaks havoc in the livestock industry of the African continent. This study evaluated the in vivo antitrypanosomal activity of geranylacetone and its ameliorative effect on the disease-induced anaemia and organ damages as well as its inhibitory effects against trypanosomal sialidase using in vitro and in silico techniques. Geranylacetone was used to treat T. congolense infected rats, at a dose of 50 and 100 mg/kg BW, for 14 days where it was found to reduce the parasite burden in the infected animals. Moreover, 100 mg/kg BW of geranylacetone significantly (p < 0.05) ameliorated the anaemia, hepatic and renal damages caused by the parasite. This is in addition to the alleviation of the parasite-induced hepatosplenomegaly and upsurge in free serum sialic acid levels in the infected animals which were associated with the observed anaemia amelioration by the compound. Consequently, bloodstream T. congolense sialidase was partially purified on DEAE cellulose column and inhibition kinetic studies revealed that the enzyme was inhibited by geranylacetone via an uncompetitive inhibition pattern. In silico analysis using molecular docking with Autodock Vina indicated that geranylacetone binds to trypanosomal sialidase with a minimum free binding energy of -5.8 kcal/mol which was mediated by 26 different kinds of non-covalent interactions excluding hydrogen bond whilst Asp163 and Phe421 had the highest number of the interactions. The data suggests that geranylacetone has trypanostatic activity and could protect animals against the T. congolense-induced anaemia through the inhibition of sialidase and/or the protection of the parasite-induced hepatosplenomegaly.

Oxidosqualene cyclase and CYP716 enzymes contribute to triterpene structural diversity in the medicinal tree banaba

Pentacyclic triterpenes (PCTs) represent a major class of bioactive metabolites in banaba (Lagerstroemia speciosa) leaves; however, biosynthetic enzymes and their involvement in the temporal accumulation of PCTs remain to be studied. We use an integrated approach involving transcriptomics, metabolomics and gene function analysis to identify oxidosqualene cyclases (OSCs) and cytochrome P450 monooxygenases (P450s) that catalyzed sequential cyclization and oxidative reactions towards PCT scaffold diversification. Four monofunctional OSCs (LsOSC1,3-5) converted the triterpene precursor 2,3-oxidosqualene to either lupeol, β-amyrin or cycloartenol, and a multifunctional LsOSC2 formed α-amyrin as a major product along with β-amyrin. Two CYP716 family P450s (CYP716A265, CYP716A266) catalyzed C-28 oxidation of α-amyrin, β-amyrin and lupeol to form ursolic acid, oleanolic acid and betulinic acid, respectively. However, CYP716C55 catalyzed C-2α hydroxylation of ursolic acid and oleanolic acid to produce corosolic acid and maslinic acid, respectively. Besides, combined transcript and metabolite analysis suggested major roles for the LsOSC2, CYP716A265 and CYP716C55 in determining leaf ursane and oleanane profiles. Combinatorial expression of OSCs and CYP716s in Saccharomyces cerevisiae and Nicotiana benthamiana led to PCT pathway reconstruction, signifying the utility of banaba enzymes for bioactive PCT production in alternate plant/microbial hosts that are more easily tractable than the tree species.

Identification of antiplasmodial triterpenes from Keetia species using NMR-based metabolic profiling

INTRODUCTION

The increase in multidrug resistance and lack of efficacy in malaria therapy has propelled the urgent discovery of new antiplasmodial drugs, reviving the screening of secondary metabolites from traditional medicine. In plant metabolomics, NMR-based strategies are considered a golden method providing both a holistic view of the chemical profiles and a correlation between the metabolome and bioactivity, becoming a corner stone of drug development from natural products.

OBJECTIVE

Create a multivariate model to identify antiplasmodial metabolites from ¹H NMR data of two African medicinal plants, Keetia leucantha and K. venosa.

METHODS

The extracts of twigs and leaves of Keetia species were measured by ¹H NMR and the spectra were submitted to orthogonal partial least squares (OPLS) for antiplasmodial correlation.

RESULTS

Unsupervised ¹H NMR analysis showed that the effect of tissues was higher than species and that triterpenoids signals were more associated to Keetia twigs than leaves. OPLS-DA based on Keetia species correlated triterpene signals to K. leucantha, exhibiting a higher concentration of triterpenoids and phenylpropanoid-conjugated triterpenes than K. venosa. In vitro antiplasmodial correlation by OPLS, validated for all Keetia samples, revealed that phenylpropanoid-conjugated triterpenes were highly correlated to the bioactivity, while the acyclic squalene was found as the major metabolite in low bioactivity samples.

CONCLUSION

NMR-based metabolomics combined with supervised multivariate data analysis is a powerful strategy for the identification of bioactive metabolites in plant extracts. Moreover, combination of statistical total correlation spectroscopy with 2D NMR allowed a detailed analysis of different triterpenes, overcoming the challenge posed by their structure similarity and coalescence in the aliphatic region.

UPLC-ESI-QTOF-MS2 characterisation of Cola nitida resin fractions with inhibitory effects on NO and TNF-α released by LPS-activated J774 macrophage and on Trypanosoma cruzi and Leishmania amazonensis

INTRODUCTION

The resin of Cola nitida is used in western Cameroon as incense for spiritual protection and during ritual ceremonies. This plant secretion has never been investigated although previous chemical and biological studies on other resins have drawn many attentions.

OBJECTIVE

The resin fractions which revealed inhibitory effect on nitric oxide (NO) and tumour necrosis factor alpha (TNF-α) released by lipopolysaccharide (LPS)-activated J774 macrophage as well as on intracellular forms of Leishmania amazonensis and Trypanosoma cruzi amastigote were chemically characterised. Moreover, their antiparasitic activities were compared to those of semi-synthetic triterpenes.

METHODOLOGY

The anti-inflammatory activity was evaluated by measuring the nitrite production and the TNF-α concentration in the supernatants of LPS-activated macrophages by antigen capture enzyme-linked immunosorbent assay. Moreover, the antiparasitic assay was performed by infecting the host cells (THP-1) in a ratio parasite/cell 10:1 (L. amazonensis) and 2:1 (T. cruzi) and then exposed to the samples. The resin was separated in vacuo by liquid chromatography because of its sticky behaviour and the chemical profiles of the obtained fractions (F1-F4) were established by dereplication based on UPLC-ESI-MS² data while semi-synthetic triterpenes were prepared from α-amyrin by oxidation reactions.

RESULTS

Fractions F1-F4 inhibited NO and TNF-α almost similarly. However, only F1, F3 and F4 showed promising antiparasitic activities while F2 was moderately active against both parasites. Hence, F1-F4 were exclusively composed of pentacyclic triterpenes bearing oleanane and ursane skeletons. Semi-synthetic compounds revealed no to moderate antiparasitic activity compared to the fractions.

CONCLUSION

Although it will be difficult to prove the interaction resin-spirit, interesting bioactivities were found in the resin fractions.

A rapid method for sensitive profiling of bioactive triterpene and flavonoid from Astragalus mongholicus and Astragalus membranaceus by ultra-pressure liquid chromatography with tandem mass spectrometry

Astragalus is one of the most popular Chinese herbal. Control of Astragalus quantity is most important, since that various varieties and ages largely affect bioactive metabolites and different pharmacological effects. Astragalus mongholicus and Astragalus membranaceus are both major sources of Astragalus according to the provisions in the Chinese Pharmacopoeia. Thus, a sensitive and rapid UPLC-MS/MS method for the simultaneous determination of l-Phenylalanine, Isoliquiritigenin, Liquiritigenin, Daidzein, Formononetin, Ononin, Calycosin, Calycosin-7-glucoside, Cycloastragenol, Astragaloside I, Astragaloside II, Astragaloside III and Astragaloside IV was established in this study. The detection was accomplished by MRM scanning in the positive ionization mode. Calibration curves offered linear ranges with r² > 0.999. The method was successfully validated for the linearity, intra-day and inter day precisions, accuracy, recovery, matrix effect and stability. Then this method was successfully applied to detect the contents of 13 target flavonoids and triterpenoids metabolites in different organs and ages of A. mongholicus and A. membranaceus. Significant organs-, ages- and varieties- specificity of the 13 target metabolites were observed and discussed. The results provided basis and support for further exploration of the distribution of bioactive metabolites, namely flavonoids and triterpenoids, in different organs and ages of two Astragalus varieties. This method should be applicable to various Astragalus matrices for the quantitative analysis of the target flavonoids and triterpenoids.

In vivo anti-malarial activity and toxicity studies of triterpenic esters isolated form Keetia leucantha and crude extracts

BACKGROUND

Considering the need for new anti-malarial drugs, further investigations on Keetia leucantha (Rubiaceae), an in vitro antiplasmodial plant traditionally used to treat malaria, were carried out. This paper aimed to assess the in vivo anti-malarial efficacy of K. leucantha triterpenic esters previously identified as the most in vitro active components against Plasmodium falciparum and their potential toxicity as well as those of anti-malarial extracts.

RESULTS

These eight triterpenic esters and the major antiplasmodial triterpenic acids, ursolic and oleanolic acids, were quantified in the twigs dichloromethane extract by validated HPLC-UV methods. They account for about 19% of this extract (16.9% for acids and 1.8% for esters). These compounds were also identified in trace in the twigs decoction by HPLC-HRMS. Results also showed that extracts and esters did not produce any haemolysis, and were devoid of any acute toxicity at a total cumulative dose of 800 and 150 mg/kg respectively. Moreover, esters given intraperitoneally at 50 mg/kg/day to Plasmodium berghei-infected mice showed a very significant (p < 0.01) parasitaemia inhibition (27.8 ± 5.4%) on day 4 post-infection compared to vehicle-treated mice.

CONCLUSIONS

These results bring out new information on the safety of K. leucantha use and on the identification of anti-malarial compounds from its dichloromethane extract. Its activity can be explained by the presence of triterpenic acids and esters which in vivo activity and safety were demonstrated for the first time.

The chemotherapeutic potential of chalcones against leishmaniases: a review

Leishmaniases are endemic diseases in tropical and sub-tropical regions of the world and are considered by the World Health Organization (WHO) to be among the six most important neglected tropical diseases. The current therapeutic arsenal against the disease is associated with a series of chemotherapeutic setbacks. However, since the early 1990s, naturally occurring chalcones with promising antileishmanial effects have been reported, and several other synthetic chalcones and chalcone-hybrid molecules have been confirmed to possess potent activity against various Leishmania species. This paper is a comprehensive review covering the antileishmanial activity of 34 naturally occurring chalcones, 224 synthetic/semisynthetic chalcones and 54 chalcone-hybrid molecules. Several chalcones in the synthetic/semisynthetic category had IC₅₀ values < 5 µM, with very good selectivity against parasites, and the structure-activity relationships as well as the proposed mechanism of action are discussed. We identified knowledge-gaps with the hope of providing future direction for the discovery of novel antileishmanial drugs from chalcones.