Mechanisms of 1-hydroxy-2-hydroxymethylanthraquinone from Coptosapelta flavescens as an anti-giardial activity

Anti-adherent effects of Rhizophora apiculata bark and leaf extracts and computational prediction of the effects of its compound on β-tubulin interaction in Acanthamoeba triangularis genotype 4

Background and Aim

Acanthamoeba, an opportunistic protozoan, exists widely in natural sources and can cause infections in humans and animals. The absence of effective monotherapy after the initial infection leads to chronic disease and recurrence. Tubulin protein is a vital target for design-targeted drug discovery. Anti-tubulin drugs are also used to treat Acanthamoeba infections, although resistance to these drugs has been observed. Therefore, it is necessary to identify a new targeted drug for Acanthamoeba infections. Therefore, this study aimed to assess the in vitro activity of ethanol extracts of Rhizophora apiculata extracts (RAE) against Acanthamoeba spp. and to predict its chemical compound on β-tubulin interaction.

Materials and Methods

In this study, anti-Acanthamoeba activity with minimal inhibitory concentration (MIC) and minimal parasiticidal concentration (MPC) determination of ethanolic RAE from leaves, blossoms, buds, branches, and barks was tested on four Acanthamoeba trophozoites and cysts: Acanthamoeba triangularis WU 19001, Acanthamoeba polyphaga American Type Culture Collection (ATCC) 30461, Acanthamoeba castellanii ATCC 50739, and A. castellanii ATCC 30010. The inhibitory effect on adherence was determined by the ability of Acanthamoeba adherence on 96-well plates, and its adhesive acanthopodia structure was evaluated using scanning electron microscopy analysis. In addition, the minimum cytotoxic concentrations (MCC) of R. apiculata leaf extract (RALE) and bark extract (RABE) were evaluated on Vero and HaCaT cell lines using the MTT assay. Phytochemical compounds from RALE and RABE were also analyzed by gas chromatography-mass spectrometry (GC-MS). Molecular docking and molecular dynamic analysis predicted the binding sites of chemicals in extracts and β-tubulin protein.

Results

The results revealed that A. triangularis and A. polyphaga trophozoites had the highest inhibition at 90% at a MIC of 8 mg/mL after treatment with RALE and RABE, respectively, at 24 h. Those MPC values were exhibited at 16 mg/mL against A. triangularis trophozoites. In addition, both extracts inhibited the adhesive properties of all Acanthamoeba approximately 80%-90% at 4 mg/mL, as well as adherent structural acanthopodia loss. MCC was 0.25 mg/mL, provided to be harmless to mammalian cells. GC-MS analysis supported that 8 and 11 major phytochemicals were from RABE and RALE, respectively. Molecular docking and molecular dynamics demonstrated that Acanthamoeba-β-tubulin exhibited potent root-mean-square deviation, root mean square fluctuation, and binding free energy values with clionasterol (from RABE and RALE) and stigmasterol (from RALE). Based on our results, ethanolic RABE and RALE exhibited anti-Acanthamoeba activity in reducing adhesion. In silico showed that promising clionasterol and stigmasterol interacted with a targeting β-tubulin.

Conclusion

The RABE and RALE exhibited a potential anti-adherent effect on A. triangularis, low toxicity, and the clionasterol and stigmasterol in RABE and RALE predicted to interact the targeted β-tubulin. These agents may be used as alternative therapeutic agents in the management of disease using a sustainable one-heath approach.

Plant anthraquinones: Classification, distribution, biosynthesis, and regulation

Anthraquinones are polycyclic compounds with an unsaturated diketone structure (quinoid moiety). As important secondary metabolites of plants, anthraquinones play an important role in the response of many biological processes and environmental factors. Anthraquinones are common in the human diet and have a variety of biological activities including anticancer, antibacterial, and antioxidant activities that reduce disease risk. The biological activity of anthraquinones depends on the substitution pattern of their hydroxyl groups on the anthraquinone ring structure. However, there is still a lack of systematic summary on the distribution, classification, and biosynthesis of plant anthraquinones. Therefore, this paper systematically reviews the research progress of the distribution, classification, biosynthesis, and regulation of plant anthraquinones. Additionally, we discuss future opportunities in anthraquinone research, including biotechnology, therapeutic products, and dietary anthraquinones.

Anti-arthritic activity and phytochemical composition of "Cao Khai" (Aqueous extracts of Coptosapelta flavescens Korth.)

For a long time, ethnic minorities in Ninh Thuan province have combined "Day Khai" (Coptosapelta flavescens Korth) with many other medicinal herbs, creating an esoteric remedy called "Cao Khai"-an aqueous extract from Day Khai. This study tested an aqueous extract from "Day Khai" for total phenolics, total flavonoids, antioxidant, and anti-inflammatory activity in an in vivo mice model. The aqueous extracts of raw materials C. flavescens collected in different regions were found to have phenolics, flavonoids, and antioxidant capacity in vitro according to DPPH, ABTS, RP, TAC, and FRAP methods. This study evaluated the effect of C. flavescens on arthritis of Complete Freund's adjuvant (CFA) induced-mice by observing changes in the degree of edema in the leg joints blood index and histology. The findings indicated that the "Cao Khai" had anti-inflammatory benefits and lowered the inflammatory symptoms in mice equivalent to Mobic medications (p < 0.05) while also limiting cartilage tissue damage after 14 days of usage. As a result, it is clear that "Cao Khai" can be considered a medicinal herb with tremendous potential for usage as an addition to illness therapy that should be protected and cultivated.

Specialised metabolites as chemotaxonomic markers of Coptosapelta diffusa, supporting its delimitation as sisterhood phylogenetic relationships with Rubioideae

From the aerial extracts of Coptosapelta diffusa (Champ. ex Benth.) Steenis, twenty-one compounds were isolated and identified by means of column chromatography and NMR and MS techniques, respectively. Amongst, ten ones were determined to be undescribed compounds including six seco-iridoid glucosides (1-6), 2-(hydroxymethyl)-1,2,3,4-tetrahydroanthracene-9,10-dione (7) and three guaiane-type sesquiterpenes (15-17). Compounds 7, 8 and 9 exhibited inhibitory activities against Staphylococcus aureus ATCC25923 with MIC of 8, 4 and 8 μg/mL. The use of 1-6 (iridoids), 7-14 (anthraquinones) and 15-17 (sesquiterpenes) as chemotaxonomic markers for this species was evidenced. Structurally, 7-14 are similar to those anthraquinones isolated from other species of the family Rubiaceae, confirming their close phylogenetic relationship. Whereas, these iridoids and sesquiterpenes with unique structures provided chemotaxonomic evidence to support the genus Coptosapelta (the tribe Coptosapelteae) as a sister of the subfamily Rubioideae. These results contrast with the general producing tendency of indole alkaloids by the species of the subfamily Cinchonoideae, and merit chemotaxonomic significance for the delimitation of Coptosapelta.