Anthelmintic screening of Bangladeshi medicinal plants and related phytochemicals using in vitro and in silico methods: An ethnobotanical perspective.

ETHNOPHARMACOLOGICAL RELEVANCE: Infections caused by parasitic worms or helminth continue to pose a great burden on human and animal health, particularly in underdeveloped tropical and subtropical countries where they are endemic. Current anthelmintic drugs present serious limitations and the emergence of drug resistance has made it increasingly challenging to combat such infections (helminthiases). In Bangladesh, medicinal plants are often used by indigenous communities for the treatment of helminthiases. Knowledge on such plants along with screening for their anthelmintic activity has the potential to lead to the discovery of phytochemicals that could serve as novel molecular scaffolds for the development of new anthelminthic drugs. AIM OF THE STUDY: The purpose of this study was i) to conduct an ethnobotanical survey to gather data on Bangladeshi medicinal plants used in the treatment of helminthiases, ii) to test plants with the highest use values for their in vitro anthelmintic activity, and iii) to carry out in silico screening on phytochemicals present in the most active plant extract to investigate their ability to disrupt ß-tubulin function in helminths. METHODS: The ethnobotanical survey was conducted across three sub-districts of Bangladesh, namely Mathbaria, Phultala and Khan Jahan Ali. The in vitro screening for anthelmintic activity was performed in a motility test using adult Haemonchus contortus worms. Virtual screening using PyRx was performed on the phytochemicals reported from the most active plant, exploring their interactions with the colchicine binding site of the ß-tubulin protein target (PDB ID: 1SA0). RESULTS: The survey respondents reported a total of 32 plants for treating helminthiases. Based on their use values, the most popular choices were Ananas comosus (L.) Merr., Azadirachta indica A.Juss., Carica papaya L., Citrus maxima (Burm.) Merr., Curcuma longa L., Momordica charantia L., Nigella sativa L. and Syzygium cumini (L.) Skeels. In vitro anthelmintic testing revealed that A. indica leaves and bark had the highest activity with LC50 values of 16 mg/mL in both cases. Other plant extracts also exhibited good anthelmintic activity with LC50 values ranging from 16 to 52 mg/mL, while the value for albendazole (positive control) was 8.39 mg/mL. The limonoids nimbolide and 28-deoxonimbolide showed a binding affinity of -8.9 kcal/mol, and satisfied all drug-likeness parameters. The control ligand N-deacetyl-N-(2-mercaptoacetyl)colchicine had a binding affinity of -6.9 kcal/mol. CONCLUSION: Further in silico and in vitro studies are warranted on the identified limonoids to confirm the potential of these derivatives as novel drug templates for helminthiases. The current study supports the need for an ethnobotanical survey-based approach to discover novel drug templates for helminthiases.

Curcumenol isolated from Curcuma zedoaria suppresses Akt-mediated NF-κB activation and p38 MAPK signaling pathway in LPS-stimulated BV-2 microglial cells.

Curcumenol, a sesquiterpene isolated from Curcuma zedoaria is known to possess a variety of health and medicinal values which includes neuroprotection, anti-inflammatory, anti-tumor and hepatoprotective activities. The current study aim is to investigate the modulatory effects of curcumenol towards the lipopolysaccharides (LPS)-induced inflammation in BV-2 microglia. Curcumenol markedly decreased LPS-induced production of nitric oxide (NO), pro-inflammatory cytokines [(IL-6) and (TNF-α)] and pro-inflammatory proteins expression, iNOS and COX-2. Moreover, curcumenol inhibited NF-κB activation by suppressing the nuclear translocation of the NF-κB p65 subunit and blocking IκBα phosphorylation and degradation. Furthermore, an NF-κB inhibitor, ethyl 3,4-dihydroxycinnamate also known as caffeic acid ethyl ester (CAEE), attenuated LPS-stimulated iNOS and COX-2 expression, suggesting that NF-κB inhibition is a regulator in the expression of iNOS and COX-2 proteins. Further mechanistic study with an Akt inhibitor, triciribine hydrate (API-2), revealed that curcumenol acted through Akt-dependent NF-κB activation. Moreover, curcumenol inhibition on LPS-induced phosphorylation of p38 MAPK is confirmed by its inhibitor (SB 202190). These results indicate that curcumenol diminishes the proinflammatory mediators and the expression of the regulatory genes in LPS-stimulated BV-2 by inhibiting Akt-dependent NF-κB activation and downregulation of Akt and p38 MAPKs signaling.

Spectrofluorometric and molecular docking studies on the binding of curcumenol and curcumenone to human serum albumin.

Curcumenol and curcumenone are two major constituents of the plants of medicinally important genus of Curcuma, and often govern the pharmacological effect of these plant extracts. These two compounds, isolated from C. zedoaria rhizomes were studied for their binding to human serum albumin (HSA) using the fluorescence quench titration method. Molecular docking was also performed to get a more detailed insight into their interaction with HSA at the binding site. Additions of these sesquiterpenes to HSA produced significant fluorescence quenching and blue shifts in the emission spectra of HSA. Analysis of the fluorescence data pointed toward moderate binding affinity between the ligands and HSA, with curcumenone showing a relatively higher binding constant (2.46 × 105 M-1) in comparison to curcumenol (1.97 × 104 M-1). Cluster analyses revealed that site I is the preferred binding site for both molecules with a minimum binding energy of -6.77 kcal·mol-1. However, binding of these two molecules to site II cannot be ruled out as the binding energies were found to be -5.72 and -5.74 kcal·mol-1 for curcumenol and curcumenone, respectively. The interactions of both ligands with HSA involved hydrophobic interactions as well as hydrogen bonding.

Evaluation of acute toxicity and gastroprotective activity of curcuma purpurascens BI. rhizome against ethanol-induced gastric mucosal injury in rats.

BACKGROUND: Curcuma purpurascens BI. is a medicinal plant from the Zingiberaceae family, which is widely used as a spice and as folk medicine. The aim of the present study is to investigate the gastroprotective activity of C. purpurascens rhizome hexane extract (CPRHE) against ethanol- induced gastric ulcers in rats. METHODS: Acute toxicity test was carried out on 36 rats (18 males and 18 females) with low dose of CPRHE (1 g/kg), high dose of CPRHE (2 g/kg) and vehicle (5% Tween 20). To determine the gastroprotective effect of CPRHE, gastric juice acidity, gross and histological gastric lesions, mucus content and ulcer index were evaluated in ethanol-induced ulcer in rats. In addition, superoxide dismutase activity, nitric oxide level and immunohistochemical evaluation of Bax and HSP70 proteins were examined. RESULTS: The CPRHE acute toxicity test on rats did not reveal any signs of mortality and toxicity up to 2 g/kg. The oral administration of CPRHE at doses of 200 mg/kg and 400 mg/kg and omeprazole (positive control) at a dose of 20 mg/kg to rats remarkably attenuated gastric lesions induced by ethanol. Pre-treatment of rats with CPRHE significantly replenished the depletion of mucus content caused by ethanol administration and decreased the acidity of gastric walls. Further examination of gastric mucosal homogenate revealed significant elevation of superoxide dismutase and nitric oxide activities and reduction in malondialdehyde level in CPRHE-treated group, compared to the lesion control group. Histological assessment of gastric walls obtained from rats pre-treated with CPRHE demonstrated a noteworthy decrease in hemorrhagic mucosal lesions. Immunohistochemical staining showed down-regulation of Bax protein and up-regulation of Hsp70 protein. CONCLUSION: Taken together, these findings confirmed the gastroprotective effect of Curcuma purpurascens rhizome against gastric damage.

Prevalence of nitrite and nitrate contents and its effect on edible bird nest's color.

Edible bird nests (EBNs) are important ethnomedicinal commodity in the Chinese community. Recently, But and others showed that the white EBNs could turn red by vapors from sodium nitrite (NaNO2) in acidic condition or from bird soil, but this color-changing agent remained elusive. The aim of this study was to determine the prevalence of nitrite and nitrate contents and its affects on EBN's color. EBNs were collected from swiftlet houses or caves in Southeast Asia. White EBNs were exposed to vapor from NaNO2 in 2% HCl, or bird soil. The levels of nitrite (NO2-) and nitrate (NO3-) in EBNs were determined through ion chromatography analysis. Vapors from NaNO2 in 2% HCl or bird soil stained white bird nests to brown/red colors, which correlated with increase nitrite and nitrate levels. Moreover, naturally formed cave-EBNs (darker in color) also contained higher nitrite and nitrate levels compared to white house-EBNs, suggesting a relationship between nitrite and nitrate with EBN's color. Of note, we detected no presence of hemoglobin in red "blood" nest. Using infrared spectra analysis, we demonstrated that red/brown cave-EBNs contained higher intensities of C-N and N-O bonds compared to white house-EBNs. Together, our study suggested that the color of EBNs was associated with the prevalence of the nitrite and nitrate contents.