Design, in silico and in vitro evaluation of curcumin analogues against Plasmodium falciparum

The influence of plant extracts on viability of ST3 and ST7 subtypes of Blastocystis sp

Blastocystis sp. is one of the most frequently detected protozoa during stool specimen examination. In the last decade, the studies about the pathogenic potential of Blastocystis sp. have intensified. Additionally, treatment approaches against this parasite are still disputable. The study aimed to investigate the in vitro activity of the substances of natural origin against two subtypes (ST) of Blastocystis sp.-ST3 and ST7. Garlic and turmeric extracts exhibited the highest inhibitory effect in relation to the ST3 viability. While horseradish and turmeric were found to be the most effective extracts to the ST7 viability. The study showed that ginger, garlic, horseradish, and turmeric extracts have potent antimicrobial activity against Blastocystis ST3 and ST7, with the half-maximal inhibitory concentration (IC50) ranging from 3.8 to 4.8 µg/ml and from 3.3 to 72.0 µg/ml, respectively, and thus may be useful in the prevention and control of Blastocystis infections. Additionally, this research confirmed that Blastocystis ST7 is more resistant to the selected plant extracts treatment than Blastocystis ST3 which in consequence may bring some difficulties in its eradication.

Trichinella spiralis: A new parasitic target for curcumin nanoformulas in mice models

Trichinosis spiralis is a global disease with significant economic impact. Albendazole is the current-treatment. Yet, the world-widely emerging antimicrobial resistance necessitates search for therapeutic substitutes. Curcumin is a natural compound with abundant therapeutic benefits. This study aimed to evaluate the potential of crude-curcumin, chitosan and for the first time curcumin-nano-emulsion and curcumin-loaded-chitosan-nanoparticles against Trichinella spiralis adults and larvae in acute and chronic trichinosis models. Trichinosis spiralis was induced in 96 Swiss-albino mice. Infected mice were divided into 2 groups. Group I constituted the acute model, where treatment started 2 h after infection for 5 successive days. Group II constituted the chronic model, where treatment started at the 30th day-post-infection and continued for 10 successive days (Refer to graphical abstract). Each group contained 8 subgroups that were designated Ia-Ih and IIa-IIh and included; a; Untreated-control, b; Albendazole-treated (Alb-treated), c; Crude-curcumin-treated (Cur-treated), d; Curcumin-nanoemulsion-treated (Cur-NE-treated), e; Albendazole and crude-curcumin-treated (Alb-Cur-treated), f; Albendazole and curcumin-nanoemulsion-treated (Alb-Cur-NE-treated), g; Chitosan-nanoparticles-treated (CS-NPs-treated) and h; Curcumin-loaded-chitosan-nanoparticles-treated (Cur-CS-NPs-treated). Additionally, six mice constituted control-uninfected group III. The effects of the used compounds on the parasite tegument, in-vivo parasitic load-worm burden, local pathology and MDA concentration in small intestines of acutely-infected and skeletal muscle of chronically-infected mice were studied. Results showed that albendazole was effective, yet, its combination with Cur-NE showed significant potentiation against adult worms and muscle larvae and alleviated the pathology in both models. Cur-CS-NPs exhibited promising results in both models. Crude-curcumin showed encouraging results especially against muscle larvae on long-term use. Treatments effectively reduced parasite load, local MDA level and CD31 expression with anti-inflammatory effect in intestine and muscle sections.

Structure-activity relationship of dibenzylideneacetone analogs against the neglected disease pathogen, Trypanosoma brucei

Trypanosoma brucei is a protozoan parasite that causes Human African Trypanosomiasis (HAT), a neglected tropical disease (NTD) that is endemic in 36 countries in sub-Saharan Africa. Only a handful drugs are available for treatment, and these have limitations, including toxicity and drug resistance. Using the natural product, curcumin, as a starting point, several curcuminoids and related analogs were evaluated against bloodstream forms of T. b. brucei. A particular subset of dibenzylideneacetone (DBA) compounds exhibited potent in vitro antitrypanosomal activity with sub-micromolar EC₅₀ values. A structure-activity relationship study including 26 DBA analogs was initiated, and several compounds exhibited EC₅₀ values as low as 200 nM. Cytotoxicity counter screens in HEK293 cells identified several compounds having selectivity indices above 10. These data suggest that DBAs offer starting points for a new small molecule therapy of HAT.

Synthesis and bio-properties of 4-piperidone containing compounds as curcumin mimics

3,5-Diyliden-4-piperidone scaffold are considered as curcumin mimic exhibiting diverse bio-properties.

The Potential use of a Curcumin-Piperine Combination as an Antimalarial Agent: A Systematic Review

Malaria remains a significant global health problem, but the development of effective antimalarial drugs is challenging due to the parasite's complex life cycle and lack of knowledge about the critical specific stages. Medicinal plants have been investigated as adjuvant therapy for malaria, so this systematic review summarizes 46 primary articles published until December 2020 that discuss curcumin and piperine as antimalarial agents. The selected articles discussed their antioxidant, anti-inflammatory, and antiapoptosis properties, as well as their mechanism of action against Plasmodium species. Curcumin is a potent antioxidant, damages parasite DNA, and may promote an immune response against Plasmodium by increasing reactive oxygen species (ROS), while piperine is also a potent antioxidant that potentiates the effects of curcumin. Hence, combining these compounds is likely to have the same effect as chloroquine, that is, attenuate and restrict parasite development, thereby reducing parasitemia and increasing host survival. This systematic review presents new information regarding the development of a curcumin-piperine combination for future malaria therapy.

A Systematic Review of Curcumin and its Derivatives as Valuable Sources of Antileishmanial Agents

BACKGROUND

In recent years, antimonial agents and other synthetic antileishmanial drugs, such as amphotericin B, paromomycin, and many other drugs, have restrictions in use due to the toxicity risk, high cost, and emerging resistance to these drugs. The present study aimed to review the antileishmanial effects of curcumin, its derivatives, and other relevant pharmaceutical formulations on leishmaniasis.

METHODS

The present study was carried out according to the 06-preferred reporting items for systematic reviews and meta-analyses (PRISMA) guideline and registered in the CAMARADES-NC3Rs Preclinical Systematic Review and Meta-Analysis Facility (SyRF) database. Some English-language databases including PubMed, Google Scholar, Web of Science, EBSCO, Science Direct, and Scopus were searched for publications worldwide related to antileishmanial effects of curcumin, its derivatives, and other relevant pharmaceutical formulations, without date limitation, to identify all the published articles (in vitro, in vivo, and clinical studies). Keywords included "curcumin", "Curcuma longa", "antileishmanial", "Leishmania", "leishmaniasis", "cutaneous leishmaniasis", "visceral leishmaniasis", "in vitro", and "in vivo".

RESULTS

Out of 5492 papers, 29 papers including 20 in vitro (69.0%), 1 in vivo (3.4%), and 8 in vitro/in vivo (27.6%) studies conducted up to 2020, met the inclusion criteria for discussion in this systematic review. The most common species of the Leishmania parasite used in these studies were L. donovani (n = 13, 44.8%), L. major (n = 10, 34.5%), and L. amazonensis (n = 6, 20.7%), respectively. The most used derivatives in these studies were curcumin (n = 15, 33.3%) and curcuminoids (n = 5, 16.7%), respectively.

CONCLUSION

In the present review, according to the studies in the literature, various forms of drugs based on curcumin and their derivatives exhibited significant in vitro and in vivo antileishmanial activity against different Leishmania spp. The results revealed that curcumin and its derivatives could be considered as an alternative and complementary source of valuable antileishmanial components against leishmaniasis, which had no significant toxicity. However, further studies are required to elucidate this concluding remark, especially in clinical settings.

Exploring the powerful phytoarsenal of white grape marc against bacteria and parasites causing significant diseases

Natural extracts containing high polyphenolic concentration possess antibacterial, anti-parasitic and fungicidal activities. The present research characterises two extracts based on white grape marc, a winemaking by-product, describing their physicochemical features and antimicrobial capacities. The main components of these extracts are phenolic acids, flavan-3-ols and their gallates and flavonols and their glycosides. As a result of this complex composition, the extracts showed pronounced bioactivities with potential uses in agricultural, pharmaceutical and cosmetic industries. Polyphenol compounds were extracted by using hydro-organic solvent mixtures from the by-product of Albariño white wines (Galicia, NW Spain) production. The in vitro antimicrobial activity of these extracts was evaluated on Gram-positive and Gram-negative bacteria and Apicomplexan and Oomycota parasites. Microbial species investigated are causing agents of several human and animal diseases, such as foodborne illnesses (Bacillus cereus, Escherichia coli, Salmonella enterica, and Toxoplasma gondii), skin infections and/or mastitis (Staphylococcus aureus and Streptococcus uberis), malaria (Plasmodium falciparum) and plant infections as "chestnut ink" or "root rot" (Phytophthora cinnamomi). Both extracts showed activity against all the tested species, being nontoxic for the host. So, they could be used for the development of biocides to control a wide range of pathogenic agents and contribute to the enhancement of winemaking industry by-products.

Current Discovery Progress of Some Emerging Anti-infective Chalcones: Highlights from 2016 to 2017

The anti-infective potentials of the natural products are very well known for centuries and are a part of traditional healing. The foremost therapeutic classes include flavones, isoflavones, flavonols, flavanones, flavanols, proanthocyanidins, anthocyanidins, chalcones, and aurones. The chalcone or 1,3-diphenyl-2E-propene-1-one represents the class of natural products which are comprised of benzylideneacetophenone function; i.e. two aromatic moieties linked together by an α, β-unsaturated carbonyl bridge comprising three-carbons. At present, chalcone is one of the privileged scaffolds that can be synthesized in the laboratory to derive different pharmacologically active compounds. This article is the continued form of the previously published work on anti-infective perspectives of chalcones (highlighted till 2015). The current work emphasizes on the discovery process of the chalcone in the period of 2016 to 2017 on malaria, trypanosomiasis, leishmaniasis, filaria, tuberculosis, netamodes, Human Immunodeficiency Virus (HIV), Tobacco Mosaic Virus (TMV), Severe Acute Respiratory Syndrome (SARS), and miscellaneous conditions. This review comprehensively focuses on the latest progress related with the anti-infective chalcones. The content includes the crucial structural features of chalcone scaffold including structure-activity relationship(s) along with their plausible mechanism of action(s) from the duration Jan 2016 to Dec 2017. This literature will be of prime interest to medicinal chemists in getting ideas and concepts for better rational development of potential anti-infective inhibitors.

Drug Interactions With the Ca2+-ATPase From Sarco(Endo)Plasmic Reticulum (SERCA)

The sarco(endo)plasmic reticulum Ca²⁺-ATPase (SERCA) is an intracellular membrane transporter that utilizes the free energy provided by ATP hydrolysis for active transport of Ca²⁺ ions from the cytoplasm to the lumen of sarco(endo)plasmic reticulum. SERCA plays a fundamental role for cell calcium homeostasis and signaling in muscle cells and also in cells of other tissues. Because of its prominent role in many physiological processes, SERCA dysfunction is associated to diseases displaying various degrees of severity. SERCA transport activity can be inhibited by a variety of compounds with different chemical structures. Specific SERCA inhibitors were identified which have been instrumental in studies of the SERCA catalytic and transport mechanism. It has been proposed that SERCA inhibition may represent a novel therapeutic strategy to cure certain diseases by targeting SERCA activity in pathogens, parasites and cancer cells. Recently, novel small molecules have been developed that are able to stimulate SERCA activity. Such SERCA activators may also offer an innovative and promising therapeutic approach to treat diseases, such as heart failure, diabetes and metabolic disorders. In the present review the effects of pharmacologically relevant compounds on SERCA transport activity are presented. In particular, we will discuss the interaction of SERCA with specific inhibitors and activators that are potential therapeutic agents for different diseases.