Antitrypanosomal activity of Verbascum sinaiticum Benth. (Scrophulariaceae) against Trypanosoma congolense isolates

Optimization of Ultrasound-Assisted Extraction of Verbascum sinaiticum Leaves: Maximal Phenolic Yield and Antioxidant Capacity

Verbascum sinaiticum (Qetetina or yeahya Joro) is a medicinal plant with secondary metabolites such as phenolics, flavonoids, glycosides, saponins, and alkaloids. This study was designed to optimize the ultrasonic-assisted extraction (UAE) parameters to enhance the phenolic content and characterize the phenolic compounds using ultra-high-performance liquid chromatography, coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC-ESI-QTOF-MS/MS), and antioxidant activities in Verbascum sinaiticum extract. Extraction time, sample-to-solvent ratio, and extraction temperature were considered for UAE optimization. It was found that UAE generated the highest extraction yield (21.6%), total phenolic content (179.8 GAE mg/g), total flavonoid content (64.49 CE mg/g), DPPH (61.85 µg/mL), and ABTS (38.89 µg/mL) when compared to maceration extraction. Metabolite analysis in this study showed the detection of 17 phenolic compounds, confirming antioxidant capacities. The optimization parameters have significant effects on phenolic compounds. Scanning electron microscopy showed the presence of structural changes when UAE was used over the maceration method. The optimized UAE parameters for extraction temperature (41.43 °C), sample-to-solvent ratio (36.32 g/mL), and extraction time (33.22 min) for TPC were obtained. This study shows the potential application for UAE of Verbascum sinaiticum leaves in the development of pharmaceutical and nutraceutical products.

In vitro and in vivo antitrypanosomal activity of the fresh leaves of Ranunculus Multifidus Forsk and its major compound anemonin against Trypanosoma congolense field isolate

BACKGROUND

Animal trypanosomiasis is a major livestock problem due to its socioeconomic impacts in tropical countries. Currently used trypanocides are toxic, expensive, and the parasites have developed resistance to the existing drugs, which calls for an urgent need of new effective and safe chemotherapeutic agents from alternative sources such as medicinal plants. In Ethiopian traditional medicine fresh leaves of Ranunculus multifidus Forsk, are used for the treatment of animal trypanosomiasis. The present study aimed to evaluate the antitrypanosomal activity of the fresh leaves of R. multifidus and its major compound anemonin against Trypanosoma congolense field isolate.

METHODS

Fresh leaves of R. multifidus were extracted by maceration with 80% methanol and hydro-distillation to obtain the corresponding extracts. Anemonin was isolated from the hydro-distilled extract by preparative TLC. For the in vitro assay, 0.1, 0.4, 2 and 4 mg/ml of the test substances were incubated with parasites and cessation or drop in motility of the parasites was monitored for a total duration of 1 h. In the in vivo assay, the test substances were administered intraperitoneally daily for 7 days to mice infected with Trypanosoma congolense. Diminazene aceturate and 1% dimethylsulfoxide (DMSO) were used as positive and negative controls, respectively.

RESULTS

Both extracts showed antitrypanosomal activity although the hydro-distilled extract demonstrated superior activity compared to the hydroalcoholic extract. At a concentration of 4 mg/ml, the hydro-distilled extract drastically reduced motility of trypanosomes within 20 min. Similarly, anemonin at the same concentration completely immobilized trypanosomes within 5 min of incubation, while diminazene aceturate (28.00 mg/kg/day) immobilized the parasites within 10 min. In the in vivo antitrypanosomal assay, anemonin eliminates parasites at all the tested doses (8.75, 17.00 and 35.00 mg/kg/day) and prevented relapse, while in diminazene aceturate-treated mice the parasites reappeared on days 12 to 14.

CONCLUSIONS

The current study demonstrated that the fresh leaves of R. multifidus possess genuine antitrypanosomal activity supporting the use of the plant for the treatment of animal trypanosomiasis in traditional medicine. Furthermore, anemonin appears to be responsible for the activity suggesting its potential as a scaffold for the development of safe and cost effective antitrypanosomal agent.

Antidiabetic Activities of 80% Methanol Extract and Solvent Fractions of Verbascum Sinaiticum Benth (Scrophulariaceae) Leaves in Mice

Background

Because of the scarcity, high cost, and severe side effects of current medications, it is necessary to discover novel, safe, and affordable anti-diabetic drugs. The current study was conducted to evaluate the antidiabetic activities of Verbascum sinaiticum Benth leaves in mice.

Methods

Leaf coarse powder was extracted with 80% methanol and then fractionated with n-hexane, ethyl acetate, and distilled water. The glucose-lowering effects of V. sinaiticum at 100, 200, and 400mg/kg were then studied. Glibenclamide was used as a positive control at a dose of 5 mg/kg. For oral glucose tolerance tests and hypoglycemia tests, Tween 2% was used as a negative control, while citrate buffer was used as a negative control for antihyperglycemic investigations. The results from the study were evaluated using one-way ANOVA, and then Tukey's post hoc multiple comparison test was performed.

Results

Blood glucose levels were significantly reduced by the V. sinaiticum 80% methanol extract at 400 mg/kg (p<0.05). The blood glucose levels were significantly lowered by the aqueous residue at 400 mg/kg (p<0.05) and the ethyl acetate fractions at 200 mg/kg (p<0.01) and 400 mg/kg (p<0.001); however, none of the fraction extracts resulted in hypoglycemic shock in healthy mice. Higher glucose tolerance was seen in orally glucose-loaded mice after exposure to 80% methanol extracts at 200 and 400 mg/kg (p<0.05), the aqueous residual fraction at 200 mg/kg (p<0.01), and the ethyl acetate fraction at 200 and 400 mg/kg (p<0.05). The ethyl acetate fraction at 200 and 400 mg/kg (p<0.01), the 80% methanol extract at 400 mg/kg (p<0.05) and the aqueous residue at 400 mg/kg (p 0.01) significantly lowered blood glucose levels in streptozotocin-induced diabetic mice.

Conclusion

The results of this study revealed that the 80% methanol extract and solvent fractions of V. sinaiticum Benth leaves are endowed with antidiabetic activity.

Antidiarrheal activities of methanolic crude extract and solvent fractions of the root of Verbascum sinaiticum Benth. (Scrophularaceae) in mice

Background

In Ethiopian traditional medicine, V. sinaiticum is one of the most often utilized medicinal herbs for the treatment of diarrhea. Therefore, this study was conducted to validate the use of the plant for the treatment of diarrhea in the traditional medical practice of Ethiopia.

Methods

Castor oil-induced diarrhea, enteropooling, and intestinal motility test models in mice were used to evaluate the antidiarrheal properties of the 80% methanol crude extract and the solvent fractions of the root component of V. sinaiticum. The effects of the crude extract and the fractions on time for onset, frequency, weight, and water content of diarrheal feces, intestinal fluid accumulation, and intestinal transit of charcoal meal were evaluated and compared with the corresponding results in the negative control.

Results

The crude extract (CE), aqueous fraction (AQF), and ethyl acetate fraction (EAF) at 400 mg/kg (p < 0.001) significantly delayed the onset of diarrhea. Besides, the CE and AQF at 200 and 400 mg/kg (p < 0.001) of the doses, and EAF at 200 (p < 0.01) and 400 mg/kg (p < 0.001) significantly decreased the frequency of diarrheal stools. Furthermore, CE, AQF, and EAF at their three serial doses (p < 0.001), significantly reduced the weights of the fresh diarrheal stools as compared to the negative control. The CE and AQF at 100 (p < 0.01), and 200 and 400 mg/kg (p < 0.001) of their doses and EAF at 200 (p < 0.01) and 400 mg/kg (p < 0.001) significantly decreased the fluid contents of diarrheal stools compared to the negative control. In the enteropooling test, the CE at 100 (p < 0.05), and 200 and 400 mg/kg (p < 0.001), AQF at 200 (P < 0.05) and 400 mg/kg (p < 0.01), and EAF at 200 (p < 0.01) and 400 mg/kg (p < 0.001) significantly decreased the weights of intestinal contents compared to the negative control. Additionally, the CE at 100 and 200 (p < 0.05) and 400 mg/kg (p < 0.001), AQF at 100 (p < 0.05), 200 (p < 0.01), and 400 mg/kg (p < 0.001) of the doses, and EAF at 400 mg/kg (p < 0.05), produced significant reductions in the volumes of intestinal contents. In the intestinal motility test model, the CE, AQF, and EAF at all their serial doses (p < 0.001), significantly suppressed the intestinal transit of charcoal meal and peristaltic index compared to the negative control.

Conclusion

Overall, the results of this study showed that the crude extract and the solvent fractions of the root parts of V. sinaiticum had considerable in vivo antidiarrheal activities. Besides, the crude extract, especially at 400 mg/kg, produced the highest effect followed by the aqueous fraction at the same dose. This might indicate that the bioactive compounds responsible for the effects are more of hydrophilic in nature. Moreover, the antidiarrheal index values were increased with the doses of the extract and the fractions, suggesting that the treatments might have dose-dependent antidiarrheal effects. Additionally, the extract was shown to be free of observable acute toxic effects. Thus, this study corroborates the use the root parts of V. sinaiticum to treat diarrhea in the traditional settings. Furthermore, the findings of this study are encouraging and may be used as the basis to conduct further studies in the area including chemical characterization and molecular based mechanism of actions of the plant for its confirmed antidiarrheal effects.

An Assessment of the In Vitro Models and Clinical Trials Related to the Antimicrobial Activities of Phytochemicals

An increased number antibiotic-resistant bacteria have emerged with the rise in antibiotic use worldwide. As such, there has been a growing interest in investigating novel antibiotics against antibiotic-resistant bacteria. Due to the extensive history of using plants for medicinal purposes, scientists and medical professionals have turned to plants as potential alternatives to common antibiotic treatments. Unlike other antibiotics in use, plant-based antibiotics have the innate ability to eliminate a broad spectrum of microorganisms through phytochemical defenses, including compounds such as alkaloids, organosulfur compounds, phenols, coumarins, and terpenes. In recent years, these antimicrobial compounds have been refined through extraction methods and tested against antibiotic-resistant strains of Gram-negative and Gram-positive bacteria. The results of the experiments demonstrated that plant extracts successfully inhibited bacteria independently or in combination with other antimicrobial products. In this review, we examine the use of plant-based antibiotics for their utilization against antibiotic-resistant bacterial infections. In addition, we examine recent clinical trials utilizing phytochemicals for the treatment of several microbial infections.

Anti-Inflammatory and Analgesic Activity of Methanolic Root Extract of Verbascum sinaiticum Benth

INTRODUCTION

Pain in its various forms is undoubtedly the most common ailment known to human beings. Non-steroidal anti-inflammatory drugs (NSAIDs) and opioid analgesics are widely used to treat pain. However, long-term use of NSAIDs and opioids causes serious adverse effects on various organs. As a result, looking for drugs with better efficacy and lesser adverse effects appears crucial. For this purpose the obvious search begins from traditional medicines, particularly herbs. Therefore, this study investigated analgesic and anti- inflammatory activity of 80% methanol root extract of Verbasicum sinaiticum Benth (VS) in vivo.

METHODS

The dried and crushed plant material was macerated with 80% methanol sequentially and dried with lyophilizer. As per the acute toxicity study conducted elsewhere, 100 mg/kg, 200 mg/kg and 400 mg/kg doses of extract were used in the acetic acid induced writhing, hot plate test, as well as carrageenan and formalin induced anti-inflammatory models. As a positive control, aspirin 150 mg/kg was used for anti-nociceptive and anti-inflammatory model and morphine 10 mg/kg was used for central analgesic models.

RESULTS

VS200 and VS400 doses of the extract significantly (p< 0.05) reduced acetic acid induced writhing as compared with the control group. Similarly in hot plate test also, both VS200 and VS400 groups demonstrated significant (p< 0.05 at 30 min and p< 0.001 at 60 and 120 min) analgesic effect in comparison with the control and VS100 groups. Furthermore, in carrageenan and formalin induced anti-inflammatory test both VS200 and VS400 were shown to produce significant (p< 0.05) anti-inflammatory effect at the later hours and days.

CONCLUSION

The findings from this study suggest that 80% methanol root extract of V. sinaiticum possesses peripheral and central analgesic as well as anti-inflammatory activity, possibly emanating from the phytochemicals present in the hydroalcoholic crude extract.

Wound Healing and Antioxidant Properties of 80% Methanol Leaf Extract of Verbascum sinaiticum (Scrophulariaceae): An Ethiopian Medicinal Plant

Wounds account for severe morbidity, socioeconomic distress, and mortality around the globe. For several years, various herbal products are used to expedite and augment the innate wound healing process. In Ethiopian folkloric medicine, Verbascum sinaiticum L. (V. sinaiticum) is commonly applied as a wound-healing agent. The present study investigated the potential wound healing and antioxidant properties of hydroalcoholic leaf extract of V. sinaiticum. The 80% methanol extract, formulated as 5% (w/w) and 10% (w/w) ointments, was evaluated in excision and incision wound models using nitrofurazone and simple ointment as positive and negative controls, respectively. Parameters such as wound contraction, period of epithelialization, and tensile strength were determined. Moreover, its in vitro antioxidant property was evaluated using a DPPH assay. In the excision model, both doses (5% and 10% w/w) of the extract showed a significant ( $p<0.001$ ) wound healing efficacy compared to the negative control as evidenced by enhanced wound contraction rate and shorter epithelialization time records. In the incision model, the lower dose (5% w/w) ointment formulation of the extract exhibited the maximum increment in tensile strength (85.6%) that was significant ( $p<0.001$ ) compared to negative and untreated controls. Animals treated with 5% w/w ointment, furthermore, showed a significantly ( $p<0.05$ ) higher percentage of tensile strength than nitrofurazone treated ones. Moreover, the hydroalcoholic extract of the plant showed a noticeable free radical scavenging property. The result of the present study upholds the folkloric use of V. sinaiticum in the treatment of wounds.

Green Synthesis of a CuO-ZnO Nanocomposite for Efficient Photodegradation of Methylene Blue and Reduction of 4-Nitrophenol

CuO-ZnO nanocomposites (NCs) were synthesized using an aqueous extract of Verbascum sinaiticum Benth. (GH) plant. X-ray diffraction (XRD), spectroscopic, and microscopic methods were used to explore the crystallinity, optical properties, morphology, and other features of the CuO-ZnO samples. Furthermore, catalytic performances were investigated for methylene blue (MB) degradation and 4-nitrophenol (4-NP) reduction. According to the results, CuO-ZnO NCs with 20 wt % CuO showed enhanced photocatalytic activity against MB dye with a 0.017 min^-1 rate constant compared to 0.0027 min^-1 for ZnO nanoparticles (NPs). Similarly, a ratio constant of 5.925 min^-1 g^-1 4-NP reductions was achieved with CuO-ZnO NCs. The results signified enhanced performance of CuO-ZnO NCs relative to ZnO NPs. The enhancement could be due to the synergy between ZnO and CuO, resulting in improved absorption of visible light and reduced electron-hole (e^-/h⁺) recombination rate. In addition, variations in the CuO content affected the performance of the CuO-ZnO NCs. Thus, the CuO-ZnO NCs prepared using V. sinaiticum Benth. extract could make the material a desirable catalyst for the elimination of organic pollutants.

In Vivo Antimalarial Activity of Leaf Extracts and a Major Compound Isolated from Ranunculus multifidus Forsk

The leaves of Ranunculus multifidus Forsk. are traditionally used for the treatment of malaria in several African countries. In the present study, 80% methanol (RM-M) and hydrodistilled (RM-H) extracts of fresh leaves from R. multifidus and its major constituent anemonin were tested for their in vivo antimalarial activity against Plasmodium berghei in mice. Anemonin was also tested for its in vitro antimycobacterial activity against Mycobacterium smegmatis and M. abscessus in a microbroth dilution assay, and bacterial growth was analyzed by OD measurement. The isolation of anemonin from RM-H was carried out using preparative thin layer chromatography (PTLC). The chemical structures of anemonin and its hydrolysis product were elucidated using spectroscopic methods (HR–MS; 1D and 2D-NMR). Results of the study revealed that both RM-M and RM-H were active against P. berghei in mice, although the latter demonstrated superior activity (p < 0.001), as compared to the former. At a dose of 35.00 mg/kg/day, RM-H demonstrated a chemosuppression value of 70% in a 4-day suppressive test. In a 4-day suppressive, Rane’s and prophylactic antimalarial tests, anemonin showed median effective doses (ED₅₀s) of 2.17, 2.78 and 2.70 μM, respectively. However, anemonin did not inhibit the growth of M. smegmatis and M. abscessus.

Comparative effects of artemether and in combination with diminazene aceturate in the treatment of experimental Trypanosoma brucei brucei infection in Wistar rats

This study assessed the effects of artemether and in combination with diminazene aceturate on parasitaemia, weight, haematology and pathology induced by experimentally Trypanosoma brucei brucei infection in Wistar rats. Fifty adult rats comprising 25 each of males and females were assigned into 5 groups of ten rats (five males and five females). Rats in group I was uninfected while groups II-V were infected with T b brucei. Groups II were untreated; III administered diminazene aceturate once; IV and V administered artemether only and in combination with diminazene aceturate respectively for 5 days. Parasitaemia was determined daily, blood was collected for haematology and weight obtained every four days for a period of 32 days. At 24 days post-treatment, rats were humanely euthanized and organs harvested for pathological examination. Results revealed parasitaemia at day 4 post-infection, significant (p < 0.05) decrease in weight, erythrogram and leucogram in all infected rats. Following treatment, there was significant (p < 0.05) decrease in parasitaemia, increased weight gain and improved haematology. Pathological examination revealed significantly (p < 0.05) decreased gross and histopathological lesions in treated groups compared to group II. In conclusion, artemether and in combination with diminazene aceturate produced antitrypanosomal effects against experimental trypanosomosis.

Ethnobotanical survey, anthelmintic effects and cytotoxicity of plants used for treatment of helminthiasis in the Central and Kara regions of Togo

Background

Traditional medicines are the main source of treatment of helminthiasis in endemic areas of Togo. The present study aimed to investigate the plants used by Traditional healers (THs) to treat helminth infections in endemic communities within the Central and Kara regions of Togo and to evaluate the anthelmintic activity of the three most cited plants.

Methods

An ethnobotanical survey was conducted from 19 to 24 June 2017 among traditional healers in the Central and Kara regions of Togo. The anthelmintic activity of the most cited plants namely Aframomum melegueta K. Schum, Khaya senegalensis A. Juss and Xylopia aethiopica A. Rich, was evaluated using microfilariae (Mf) of Litomosoides sigmodontis. The plants were evaluated for cytotoxicity according to the recommendation of NF EN ISO 10993-5 standard using the propidium iodide (PI) dye by flow cytometry on human peripheral blood mononuclear cells.

Results

A total of 197 THs were interviewed and 41 plant species were recorded. Leguminosae (14.6%) and Annonaceae (9.7%) families constitute the highest number of species cited for treatment of helminth infections. Afromomum melegueta was the most cited by the THs for the treatment of onchocerciasis (UV = 0.036) while X. aethiopica was associated with the treatment of schistosomiasis (UV = 0.061) and lymphatic filariasis (UV = 0.061). There was a great agreement among the THs regarding ethnomedicinal uses of plants to treat helminthiasis with ICF values ranging from 0.57 to 0.67. The anthelmintic assay yielded lethal doses values of 233 μg/mL, 265 μg/mL and 550 μg/mL, respectively for X. aethiopica, A. melegueta and K. senegalensis. Afromomum melegueta and X. aethiopica presented no cytotoxicity, less than 20% death, whereas K. senegalensis induced moderate toxicity, 24 ± 8% death.

Conclusion

This study demonstrated the scientific rationale for the use of plants to treat helminthiasis in the Togolese traditional medicine. However, the use of K. senegalensis requires more caution since the plant is fairly toxic.

Trial Registration

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Evaluation of antitrypanosomal activity of Pterocarpus santalinoides L'H'erit ex DC hydroethanol leaf extract in rats experimentally infected with Trypanosoma brucei

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Pterocarpus santalinoides are used alone or with other plants by traditional healers in some Southern Nigerian and Ivorian rural villages to treat blood parasitic infections including trypanosomiasis and malaria. However, their efficacy and safety remains doubtful.

AIM

To evaluate the antitrypanosomal activity of Pterocarpus santalinoides hydroethanol leaf extract (PSELE) in vitro and in vivo.

MATERIALS AND METHODS

The phytochemical and acute toxicity studies of PSELE were performed using standard methods. Eleven different concentrations of the extract were screened for in vitro antitrypanosomal activity. For the in vivo study, twenty-five female albino rats were randomly assigned into five groups of five rats each. Group A was the uninfected and untreated group while groups B - E were infected intraperitoneally with 10⁶ trypanosomes. Group C rats were treated once on day 11 post infection (PI) with 7 mg/kg diminazene aceturate while groups D and E rats were also treated on same day with 200 mg/kg and 400 mg/kg PSELE respectively for seven days. The level of parasitaemia (LOP), survivability, packed cell volume (PCV), total leucocyte count (TLC), total erythrocyte count (TEC), body weight and rectal temperature were used to assess the antitrypanosomal effect of PSELE.

RESULTS

Phytochemical analysis revealed the presence of flavonoids, tannins, carbohydrates and reducing sugar. No sign of toxicity or mortality was observed following acute toxicity study at a single dose of 2000 mg/kg. The LC₅₀ of PSELE was 0.0625 mg/ml. Parasitaemia was first detected on day 8 and all infected rats became parasitaemic on day 10 (PI). PSELE significantly reduced (p < 0.05) LOP, improved PCV, TEC and prolonged survival time of the rats compared with the infected untreated group B.

CONCLUSION

It was therefore concluded that PSELE is safe, possesses some antitrypanosomal activity and may serve as a lead for the development of an effective alternative antitrypanosomal drug.