Effects of Crinum jagus Water/Ethanol Extract on Shigella flexneri-Induced Diarrhea in Rats

A Review of Preclinical Tools to Validate Anti-Diarrheal Agents

BACKGROUND

Since their inception, preclinical experimental models have played an important role in investigating and characterizing disease pathogenesis. These in vivo, ex vivo, and in vitro preclinical tests also aid in identifying targets, evaluating potential therapeutic drugs, and validating treatment protocols.

INTRODUCTION

Diarrhea is a leading cause of mortality and morbidity, particularly among children in developing countries, and it represents a huge health-care challenge on a global scale. Due to its chronic manifestations, alternative anti-diarrheal medications must be tested and developed because of the undesirable side effects of currently existing anti-diarrheal drugs.

METHODS

Several online databases, including Science Direct, PubMed, Web of Science, Google Scholar and Scopus, were used in the literature search. The datasets were searched for entries of studies up to May, 2022.

RESULTS

The exhaustive literature study provides a large number of in vivo, in vitro and ex vivo models, which have been used for evaluating the mechanism of the anti-diarrheal effect of drugs in chemically-, pathogen-, disease-induced animal models of diarrhea. The advances and challenges of each model were also addressed in this review.

CONCLUSION

This review encompasses diverse strategies for screening drugs with anti-diarrheal effects and covers a wide range of pathophysiological and molecular mechanisms linked to diarrhea, with a particular emphasis on the challenges of evaluating and predictively validating these experimental models in preclinical studies. This could also help researchers find a new medicine to treat diabetes more effectively and with fewer adverse effects.

Anxiolytic and anti-colitis effects of Moringa oleifera leaf-aqueous extract on acetic acid-induced colon inflammation in rat

Moringa oleifera decoction is believed to alleviate gastrointestinal tract diseases. This study investigated antioxidant and anxiolytic activities of its leaves aqueous extract on acetic acid-induced colitis in rats. Rats (36) were randomly divided into six groups and received (20 days) distilled water, 10 mL/kg; Moringa oleifera leaf-aqueous extract (25, 50, and 100 mg/kg) or Loperamide (5 mg/kg). On days 1, 8, 17, and 20, behavioral parameters were evaluated. Colitis was induced (day 15, except in normal group) through acetic acid (4%, 1 mL) intra-rectal administration. After sacrifice (day 21), lesion number, weight/length ratio of the colon were recorded. Oxidative stress biomarkers were evaluated. On day 20, Moringa oleifera (100 mg/kg) reduced the number of head dipping and the duration in opened arms, respectively 2.00 ± 0.37 and 5.00 ± 0.37 s against 14.50 ± 0.72 and 2.17 ± 0.48 s in the control. It decreased colon weight/length ratio: 112.29 ± 9.46 against 185.93 ± 5.28 mg/cm in the control; malondialdehyde level (P < 0.01) and nitric oxide concentration (P < 0.001), in the brain: respectively 25.60 ± 0.60 and 36.34 ± 1.19 against 34.00 ± 0.33 and 46.17 ± 3.25 µmol/mg of tissue in the control. In the serum, the extract (50 mg/kg) significantly (P < 0.05) increased the catalase activity (0.10 ± 0.00 against 0.03 ± 0.00 µmol/mg of protein in the negative control group). At 100 mg/kg, it increased (P < 0.001) reduced glutathione concentration to 5.07 ± 0.31 against 3.26 ± 0.08 µmol/mg of protein in the negative control group. The improvement on colitis pathophysiology, the antioxidant and the anxiolytic effects noted therefore suggest that Moringa oleifera can be a potential source of drugs alleviating anxiety and oxidative stress associated to ulcerative colitis.

The Phytochemistry and Pharmacology of Tulbaghia, Allium, Crinum and Cyrtanthus: ‘Talented’ Taxa from the Amaryllidaceae

Amaryllidaceae is a significant source of bioactive phytochemicals with a strong propensity to develop new drugs. The genera Allium, Tulbaghia, Cyrtanthus and Crinum biosynthesize novel alkaloids and other phytochemicals with traditional and pharmacological uses. Amaryllidaceae biomolecules exhibit multiple pharmacological activities such as antioxidant, antimicrobial, and immunomodulatory effects. Traditionally, natural products from Amaryllidaceae are utilized to treat non-communicable and infectious human diseases. Galanthamine, a drug from this family, is clinically relevant in treating the neurocognitive disorder, Alzheimer’s disease, which underscores the importance of the Amaryllidaceae alkaloids. Although Amaryllidaceae provide a plethora of biologically active compounds, there is tardiness in their development into clinically pliable medicines. Other genera, including Cyrtanthus and Tulbaghia, have received little attention as potential sources of promising drug candidates. Given the reciprocal relationship of the increasing burden of human diseases and limited availability of medicinal therapies, more rapid drug discovery and development are desirable. To expedite clinically relevant drug development, we present here evidence on bioactive compounds from the genera Allium, Tulgbaghia, Cyrtanthus and Crinum and describe their traditional and pharmacological applications.

Evaluation of anti-biofilm, anti-quorum, anti-dysenteric potential of designed polyherbal formulation: in vitro and in vivo study

Bacillary dysentery (shigellosis) continues to cause havoc worldwide, with a high infectivity rate. It causes bloody diarrhea, and around 99% of bacillary dysentery cases occur in developing countries. The objective of this study is to develop a polyherbal formulation with the scientific rationale in treating infectious bacillary dysentery disease. The anti-bacterial activity, the minimum inhibitory concentration of the formulation against bacillary dysentery, causing microbes like Shigella flexneri (MTCC 1457), Escherichia coli (MTCC 1687), and Salmonella enterica (MTCC 98), was analysed by well-diffusion method and broth dilution method, respectively. The biofilm inhibition activity was determined on 96 well polystyrene plates and anti-quorum sensing activity by Chromobacterium violaceum CV026. The cytotoxicity was examined by acute oral toxicity. Excreta and organ bacterial load were analyzed by serial dilution method. The formulation efficacy was determined by analyzing the blood sample of rats. The antimicrobial efficacy of the developed formulation was calculated by measuring the zone of inhibition which was found to be 24 mm, 25 mm, and 25 mm, and the MIC values of 1.5 mg/ml, 1.5 mg/ml, and 2.0 mg/ml against S. flexneri, S. enterica, E. coli, respectively. The results show that the polyherbal formulation significantly reduced biofilm formation and has anti-quorum sensing activity. The formulation also effectively decreases the bacterial load and increases the K+, Na+, and Ca++ ions in animals treated with the formulation. The developed formulation was found to be non-toxic and effective against bacillary dysentery; thus, it can be used for treating bacillary dysentery and related complications.

A Novel Bacteriocin Against Shigella flexneri From Lactiplantibacillus plantarum Isolated From Tilapia Intestine: Purification, Antibacterial Properties and Antibiofilm Activity

Few bacteriocins with antibacterial activity against Shigella flexneri have been reported. Here, a novel bacteriocin (LFX01) produced by Lactiplantibacillus plantarum strain LF-8 from the intestine of tilapia was purified and extensively characterized. LFX01 possesses a molecular weight of 1049.56 Da and an amino acid sequence of I-T-G-G-P-A-V-V-H-Q-A. LFX01 significantly inhibited S. flexneri strain 14 (S. flexneri_14) growth. Moreover, it exhibited excellent stability under heat and acid-base stress, and presented sensitivity to a variety of proteases, such as proteinase K, pepsin, and trypsin. The minimum inhibitory concentration (MIC) of LFX01 against S. flexneri_14 was 12.65 μg/mL, which was smaller than that of most of the previously found bacteriocins. Furthermore, LFX01 significantly inhibited (p < 0.05) S. flexneri_14 cells and decreased their cell viability. In addition, LFX01 could significantly (p < 0.05) inhibit biofilm formation of S. flexneri_14. Scanning electron microscopy analysis presented that the cell membrane permeability of S. flexneri_14 was demolished by LFX01, leading to cytoplasmic contents leakage and cell rupture death. In summary, a novel bacteriocin of lactic acid bacteria (LAB) was found, which could effectively control S. flexneri in both planktonic and biofilm states.

An in vivo acute toxicity and anti-shigellosis effect of designed formulation on rat

INTRODUCTION

Shigellosis is an intestinal disease and is one of the main causes of morbidity and mortality among children in India. The study aims to analyze the effect of the designed formulation on the hematological parameters in shigellosis-induced rats and assess the in vivo toxicity of this formulation.

METHODS

Male Wistar rats were housed in different groups. Group 1 is normal control; group 2 is diseased control; group 3 and group 4 diseased rats received 250 mg/kg formulation and 20 mg/kg body weight norfloxacin, respectively, orally once a day. Shigellosis was induced by a single intraperitoneal injection of Shigella flexneri, and bacterial load was calculated using the Shigella agar plate. On completion of the study, blood was collected for hematological as well as electrolyte analysis.

RESULTS

The in vivo acute toxicity results indicate that the formulation is safe up to 2000 mg/kg. Furthermore, formulation significantly (p < 0.05) decreases the bacterial load and increases the RBC, WBC, MCHC, platelet, hemoglobin, and electrolytes (Ca⁺⁺, K⁺, and Na⁺) compared to diseased control.

CONCLUSION

The results support the designed formulation's safety and therapeutic effects and support its use as an alternative medicine for treating shigellosis.

Screening of anti-microbial, anti-biofilm activity, and cytotoxicity analysis of a designed polyherbal formulation against shigellosis

Background

Shigellosis is an infectious intestinal disease common in rural communities. In developing countries, shigellosis is caused predominantly by Shigella flexneri and has been determined as a major cause of morbidity and mortality.

Objective

The study investigates the anti-biofilm, anti-microbial, and anti-shigellosis activity of a designed formulation.

Materials and methods

The potential of the formulation against S. flexneri (MTCC 1457) was investigated using a well-diffusion assay. Further, the effect of the designed formulation on bacterial growth and biofilm formation was analyzed by the spectrophotometry method. Anti-quorum sensing activity was analyzed using Chromobacterium violaceum CV026, a bacterial strain. Finally, the cytotoxicity of the formulation was examined by using cell line and brine shrimp lethality assay.

Results

The MIC value of the aqueous extract of the formulation was 2.4 mg ml⁻¹ and an inhibitory zone of 23 mm was observed. On the other side, the formulation significantly inhibited the bacterial growth, biofilm formation (23.78%), violacein inhibition (27.68%) at 0.6 mg ml⁻¹ concentration (did not significantly affect the growth curves) and was found non-toxic in cell assay and brine shrimp lethality assay.

Conclusion

According to the result obtained, the designed formulation was found effective and non-toxic, so it can be used to treat shigellosis and Shigella-related infections.

Anti-Shigellosis Activity of Cola anomala Water/Ethanol Pods Extract on Shigella flexneri-Induced Diarrhea in Rats

This study was undertaken to evaluate the activities of water/ethanol Cola anomala pods extract. In vitro antimicrobial susceptibility was determined by the disk diffusion method; the minimum inhibitory concentration and minimum bactericidal concentration were determined by agar dilution technique. In vivo, shigellosis was induced in healthy Wistar albino rats by oral administration of Shigella flexneri inoculum, 12 × 10⁸ CFU/mL. At the onset of diarrhea, infected and normal control animals were subdivided into various groups treated with distilled water, with water/ethanol Cola anomala pods extract at 25, 50, or 100 mg/kg, or with ciprofloxacin, 2.5 mg/kg. After one-week treatment, rats were sacrificed, and blood and colon were collected. Blood was used for blood cell count. A portion of the colon served for histological studies while homogenate from the remaining part was centrifuged and the supernatant was collected for the determination of NO, PGE₂, IL-1β, and TNF-α levels. In vitro, water/ethanol Cola anomala pods extract showed to be bactericidal, with a minimum inhibitory concentration of 2.0 mg/mL and a minimum bactericidal concentration of 3.0 mg/mL. In diarrheic rats, the extract significantly (P < 0.01) increased the white blood cells and significantly (P < 0.01) decreased stool Shigella density from the first to the seventh day of treatment. It partially restored the structure of eroded intestine epithelium and prevented weight loss; the dose dependently and significantly (P < 0.001) decreased NO, IL-1β, and TNF-α production in the colon and was found to have no significant effect on PGE₂ production. These results support the use of this plant in traditional medicine in the treatment of gastrointestinal ailments.

Effect of the Hydroethanolic Extract of Bixa orellana Linn (Bixaceae) Leaves on Castor Oil-Induced Diarrhea in Swiss Albino Mice

OBJECTIVE

The treatment of diarrheal diseases is a serious problem in developing countries, where population generally uses medicinal plants. The leaves of Bixa orellana have been reported to be traditionally used in the treatment of diarrhea by local people in the district of Khulna in Bangladesh. The aim of this study was to investigate the effects of the hydroethanolic extract of Bixa orellana leaves on castor oil-induced diarrhea in mice.

METHODS

The powder of the leaves of Bixa orellana was macerated in ethanol/water mixture (20/80) for 48 hours and then filtered. The filtrate obtained was lyophilized, and the solutions to be administered to the animals were prepared. To induce diarrhea, animals orally received castor oil (1 mL/100 g bw). To determine the effective doses, each mouse received, 30 minutes after the administration of castor oil, one of the single oral doses of hydroethanolic extract of Bixa orellana leaves: 0, 25, 50, 100, and 200 mg/kg bw. The mass, number, and frequency of stool diarrhea were measured and recorded per hour for five hours. The effect of the hydroethanolic extract of Bixa orellana leaves on the intestinal transit was evaluated by measuring the distance traveled by the charcoal meal in thirty minutes. The effects of the aqueous extract of hydroethanolic extract of Bixa orellana leaves on intestinal secretion were evaluated by measuring the volume of the intestinal content and by dosing the electrolytes (Na+, K+, and Cl-) in the intestinal content by the colorimetric method.

RESULTS

The extract produced significant (P < 0.01) decreases, respectively, 35.52%, 54.47%, 74.80%, and 87.80% in the severity of diarrhea. The extract at 100 and 200 mg/kg bw showed a significant (P < 0.01) decrease of castor oil-induced enteropooling (61.08% and 65.41%), and only the 200 mg/kg bw exhibited significant (P < 0.01) reduction on intestinal transit (24.46%) as compared to standard drug.

CONCLUSIONS

The hydroethanolic extract was found to be effective against castor oil-induced diarrhea in experimental mice at 50, 100, and 200 mg/kg bw which provides evidence that could justify its traditional use.

Animal Models of Type III Secretion System-Mediated Pathogenesis

The type III secretion system (T3SS) is a conserved virulence factor used by many Gram-negative pathogenic bacteria and has become an important target for anti-virulence drugs. Most T3SS inhibitors to date have been discovered using in vitro screening assays. Pharmacokinetics and other important characteristics of pharmaceuticals cannot be determined with in vitro assays alone. In vivo assays are required to study pathogens in their natural environment and are an important step in the development of new drugs and vaccines. Animal models are also required to understand whether T3SS inhibition will enable the host to clear the infection. This review covers selected animal models (mouse, rat, guinea pig, rabbit, cat, dog, pig, cattle, primates, chicken, zebrafish, nematode, wax moth, flea, fly, and amoeba), where T3SS activity and infectivity have been studied in relation to specific pathogens (Escherichia coli, Salmonella spp., Pseudomonas spp., Shigella spp., Bordetella spp., Vibrio spp., Chlamydia spp., and Yersinia spp.). These assays may be appropriate for those researching T3SS inhibition.

Shigella: Antibiotic-Resistance Mechanisms And New Horizons For Treatment

Shigella spp. are a common cause of diarrheal disease and have remained an important pathogen responsible for increased rates of morbidity and mortality caused by dysentery each year around the globe. Antibiotic treatment of Shigella infections plays an essential role in reducing prevalence and death rates of the disease. However, treatment of these infections remains a challenge, due to the global rise in broad-spectrum resistance to many antibiotics. Drug resistance in Shigella spp. can result from many mechanisms, such as decrease in cellular permeability, extrusion of drugs by active efflux pumps, and overexpression of drug-modifying and -inactivating enzymes or target modification by mutation. Therefore, there is an increasing need for identification and evolution of alternative therapeutic strategies presenting innovative avenues against Shigella infections, as well as paying further attention to this infection. The current review focuses on various antibiotic-resistance mechanisms of Shigella spp. with a particular emphasis on epidemiology and new mechanisms of resistance and their acquisition, and also discusses the status of novel strategies for treatment of Shigella infection and vaccine candidates currently under evaluation in preclinical or clinical phases.