<p>Anti-Nociceptive and Anti-Inflammatory Activity of <em>Hygrophila schulli</em> Leaves</p>

Purpose

The management of pain and inflammation with non-steroidal anti-inflammatory drugs and opioid analgesics are currently encountering severe adverse reactions. To overcome these problems, herbal remedies may offer new alternative medicines. Hygrophila schulli is a medicinal plant traditionally used for the treatment of pain and inflammation-related disorders; yet, these claims are not scientifically validated. Hence, this study was aimed to validate the traditional use of Hygrophila schulli leaves as anti-inflammatory and analgesic remedy.

Methods

In vitro anti-hyaluronidase assay and in vivo carrageenan-induced hind paw oedema model were used to evaluate the anti-inflammatory property of ethanolic leaf extract of Hygrophila schulli. Tail immersion and acetic acid-induced writhing tests were performed to determine the central and peripheral analgesic activity of the leaf extract, respectively.

Results

The ethanolic leaf extract exhibited significant anti-hyaluronidase activity (P<0.001) and significant inhibition of carrageenan-induced paw oedema (P<0.05) compared to untreated controls. Similarly, the extract significantly prolonged the reaction time of mice (P<0.05) for the hot-water stimuli. Furthermore, an oral dose of the extract showed significant inhibition (P<0.01) of acetic acid-induced abdominal contractions of mice. Besides, the ethanolic leaf extract did not cause any obvious sign of acute toxicity at a single oral dose of 2 g/kg.

Conclusion

The findings of this study may partially support the acclaimed traditional use of Hygrophila schulli leaves for the treatment of pain and inflammatory conditions.

In vivo Hepatoprotective and in vitro Radical Scavenging Activities of Extracts of Rumex abyssinicus Jacq. Rhizome

BACKGROUND

Liver diseases contribute a prominent global burden of mortality and morbidity. The current therapies of liver diseases have numerous limitations including severe adverse effects. This denotes that new more effective, safer, and cheaper drugs are required and medicinal plants used in traditional medicines often offer ideal opportunities. Accordingly, the present study aimed to evaluate the in vivo hepatoprotective and in vitro radical scavenging activities of dried rhizome extracts of Rumex abyssinicus (R. abyssinicus), which is traditionally claimed to provide hepatoprotection.

MATERIALS AND METHODS

Hepatoprotective activity of extracts was evaluated using carbon tetrachloride (CCl4)-induced liver injury in mice. Pre- and post-treatment models were employed to test the effect of the extracts and silymarin (standard drug). Serum biochemical markers and liver histopathology were used as parameters to evaluate hepatoprotective activities whereas in vitro radical scavenging activity was tested by 2, 2-diphenyl-2-picrylhydrazyl hydrate (DPPH) assay.

RESULTS AND CONCLUSION

Oral administration of CCl4 (1 ml/kg) significantly (P<0.001) raised the serum levels of liver enzyme markers compared to the normal control group. Pre-treatment with 125, 250, and 500 mg/kg of R. abyssinicus extract reduced the serum level of CCl4-induced rise in liver enzyme markers with the highest reduction observed at a dose of 500 mg/kg. Likewise, in the post-treatment model, the crude extract and butanol fraction at dose 500 mg/kg reduced levels of liver enzymes. Histopathological examinations revealed lesser liver damage of extract-treated mice compared to the toxic (CCl4-treated) controls. The in vitro radical scavenging activity of the different extracts showed concentration-dependent radical scavenging activity. Thus, the results of this study may justify the traditional use of the plant as a hepatoprotective agent.

CONCLUSION

Results of serum biochemical markers and histopathological examinations of CCl4-induced mice models, in the present study, show the hepatoprotective potential of extracts from the rhizome of R. abyssinicus.

Multiple Pathway-Mediated Gut-Modulatory Effects of Maerua subcordata (Gilg) DeWolf

BACKGROUND

Gastrointestinal disorders are often poorly managed, especially in developing countries, where there are limited resources and therapeutic options. Despite the rich diversity of medicinal plants that offer effective treatment options with fewer side effects, studies that provide scientific verification are lacking. Maerua subcordata (Gilg) DeWolf is among the plants claimed to have wide traditional medicine, use, including as a remedy against gastrointestinal problems. Therefore, this work aimed to evaluate the gut-modulatory effects of a crude leaf extract of M. subcordata (MSL.Cr), as well as its possible mechanism of action.

METHODS

A castor oil (10 mL/kg)-induced diarrheal mouse model was used to evaluate the antidiarrheal effect of MSL.Cr, and the spasmodic/antispasmodic effect of the extract was assessed using isolated rabbit jejunum with and without addition of standard cholinergic agonists/antagonists to predict the possible mechanism of action.

RESULTS

MSL.Cr exhibited 40% and 80% protection against castor oil-induced diarrhea in mice at doses of 500 and 1,000 mg/kg, respectively. In isolated rabbit jejunum, the extract increased spontaneous contractions at low doses (0.01-0.1 mg/mL), and was sensitive to atropine, whereas it showed complete inhibition at higher doses (0.3-1 mg/mL). It was shown that the relaxant effect was possibly mediated by the involvement of phosphodiesterase-enzyme inhibition and K+-channel activation. The extract potentiated the control concentration-response curve of carbachol, shifting it to the left, similarly to the control drug papaverine. The potassium-channel opening-like activity of MSL.Cr was possibly mediated by the involvement of aspecific K+-channels inhibition, since tetraethylammonium, anunselective antagonist of K+ channels, significantly reversed its inhibitory effect.

CONCLUSION

This study showed that the M. subcordata leaf extract demonstrated gut-modulatory effects, possibly mediated by a combination of muscarinic-receptor stimulation, phosphodiesterase inhibition, and aspecific K+-channel activation.

Antidiabetic Activity of Extracts of Terminalia brownii Fresen. Stem Bark in Mice

Background

Diabetes mellitus is a chronic metabolic disorder that imposes a huge health and economic burden on societies. Because the currently available medications have many drawbacks, it is important to search for alternative therapies. Medicinal plants used in traditional medicines are ideal candidates. Hence, this study was undertaken to investigate the antidiabetic activity of crude extract and solvent fractions from the stem bark of Terminalia brownii Fresen. (Combretaceae) in mice.

Materials and Methods

The in vitro α-amylase inhibition assay was performed using the chromogenic 3, 5-dinitrosalicylic acid (DNSA) method while the antihyperglycemic activity was assessed using three mouse models: streptozotocin-induced diabetic mice, normoglycemic mice, and oral glucose challenged mice. Experimental diabetes was induced by a single intraperitoneal injection of streptozotocin at a dose of 150 mg/kg and animals with fasting blood glucose level (BGL) >200 mg/dL were considered diabetic. Glibenclamide (5 mg/kg) was used as a standard drug. Fasting BGL and body weight were used to assess the antidiabetic activity. The result was analyzed using GraphPad Prism software version 8 and one-way ANOVA followed by Tukey’s post hoc test with p<0.05 considered as statistically significant.

Results

The crude extract of T. brownii at all tested dose levels (250, 500 and 750 mg/kg) showed a significant BGL reduction in all the three animal models. Moreover, the ethyl acetate and aqueous fractions (at 500 mg/kg) significantly (p<0.01) reduced the BGL in the streptozotocin induced diabetic model. The crude extract and different solvent fractions also showed a dose-dependent in vitro α-amylase inhibitory activity and improvement of body weight.

Conclusion

T. brownii crude extract and its solvent fractions showed a significant antihyperglycemic activity in STZ induced diabetic mice, hypoglycemic activity and improvement of oral glucose tolerance in normal mice.

In vivo hepatoprotective and In vitro radical scavenging activities of Cucumis ficifolius A. rich root extract

ETHNOPHARMACOLOGICAL RELEVANCE

Cucumis ficifolius A. Rich is a perennial prostrate herb that stems up to 1 m long. Its root is widely used in traditional medicine to treat various diseases including liver diseases. Yet, scientific evidence is lacking to verify its ethno medicinal claims.

AIM OF THE STUDY

The present study was conducted to assess the hepatoprotective and radical scavenging activity of 80% methanol crude extract and different fractions of Cucumis ficifolius root.

MATERIALS AND METHODS

Radical scavenging activity was done applying the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay while hepatoprotective activity was assessed using pre- and post-treatment models of carbon tetrachloride (CCl₄)-induced liver injury in Swiss albino mice of either sex weighing 25-30 g. A single oral dose of 2000 mg/kg was used for acute toxicity study, doses of 125, 250, and 500 mg/kg were used in the pre-treatment model, and 500 mg/kg of extract and chloroform fraction were used in the post-treatment model. Biochemical markers and histopathological parameters were used to measure hepatoprotective activities.

RESULTS

C. ficifolius crude extract and its solvent fractions showed strong radical scavenging activity and the chloroform fraction had the highest activity. No sign of toxicity was shown in an acute toxicity test of the extract. Hepatoprotective activity evaluation on the crude extract by a pre-treatment model with 125, 250, and 500 mg/kg doses revealed a significant (p < 0.05) reduction of the serum level of CCl₄-induced liver enzyme markers at the highest tested dose (500 mg/kg). The chloroform fraction that had highest radical scavenging activity and the crude extract, both at 500 mg/kg, were again evaluated in a post-treatment model and the results revealed that both the extract and the chloroform fraction demonstrated significant (p < 0.05) hepatoprotective activities which support the results of the pre-treatment model.

CONCLUSION

The present study verified the hepatoprotective potentials of C. ficifolius extract and its chloroform fraction which might be, at least in part, through radical scavenging action.

Hazard assessment of Maerua subcordata (Gilg) DeWolf. for selected endpoints using a battery of in vitro tests

ETHNOPHARMACOLOGICAL RELEVANCE

Maerua subcordata (Gilg) DeWolf is a medicinal and wild food plant growing mainly in east Africa. Especially its root tuber is widely used in traditional medicine to treat several infectious and chronic diseases but also in some toxicity implications like use as abortifacient.

AIM OF THE STUDY

the present study applied in silico and in vitro tests to identify possible hazards of M. subcordata (fruit, leaf, root, seed) methanol extracts focussing on developmental toxicity.

MATERIALS AND METHODS

Ames test, estrogen receptor alpha (ERα) assay, aryl hydrocarbon receptor (AhR) assay, embryonic stem cell test (EST), and zebrafish embryotoxicity test (ZET) were employed. Besides, a Derek Nexus toxicity prediction was performed on candidate structures obtained from metabolomics profiling of the extracts using liquid chromatography coupled to multistage mass spectroscopy (LC/MSⁿ) and a MAGMa software based structural annotation.

RESULTS

Glucosinolates, which degrade to isothiocyanates, and biogenic amines were among the candidate molecules identified in the extracts by LC/MSⁿ - MAGMa software structural annotation. Isothiocyanates and some other candidate molecules suggested a positive mutagenicity alert in Derek toxicity predictions. All the extracts showed negative mutagenicity in the Ames test. However, the Derek predictions also identified endocrine and developmental toxicity as possible endpoints of concern. This was further assessed using in vitro tests. Results obtained reveal that leaf extract shows AhR and ERα agonist activities, inhibited differentiation of ES-D3 stem cells into contracting cardiomyocytes in the EST (p < 0.001) as well as inhibited hatching (p < 0.01) and showed acute toxicity (p < 0.01) in the ZET. Also, the fruit extract showed toxicity (p < 0.05) towards zebrafish embryos and both fruit and seed extracts showed AhR agonist activities while root extract was devoid of activity in all in vitro assays.

CONCLUSION

The leaf extract tests positive in in vitro tests that may point towards a developmental toxicity hazard. The current evaluations did not raise concerns of genotoxicity or developmental toxicity for the fruit, seed and root extracts. This is important given the use of especially these parts of M. subcordata, in traditional medicine and/or as (famine) food.

Effects of Maerua subcordata (Gilg) DeWolf on electrophile-responsive element (EpRE)-mediated gene expression in vitro

Plant extracts and phytochemicals may prevent chronic diseases via activation of adaptive cellular stress response pathways including induction of antioxidant and phase II detoxifying enzymes. The regulatory regions of these inducible genes encode the electrophile-response element (EpRE). This study tested the EpRE induction ability of Maerua subcordata (fruit, leaf, root, seed) methanol extracts and selected candidate constituents thereof, identified by liquid chromatography coupled with multistage mass spectroscopy, employing an EpRE luciferase reporter gene assay using hepa-1c1c7 mouse hepatoma cells. A parallel Cytotox CALUX assay using human osteosarcoma U2OS cells was used to monitor any non-specific changes in luciferase activity or cytotoxicity. Results showed that fruit, root, and seed extracts were non-cytotoxic up to a concentration of 30 gram dry weight per litre but the leaf extract exhibited some cytotoxicity and that the leaf (despite some cytotoxicity), fruit, and seed extracts showed strong induction of EpRE mediated gene expression while induction by the root extract was minimal. Selected candidates included glucosinolates, isothiocyanates, and some biogenic amines. Subsequent studies showed that methyl-, ethyl-, isopropyl-, isobutyl- isothiocyanates, and sec-butyl thiocyanate as well as glucobrassicin induced concentration (1–100 μM) dependent EpRE-mediated gene expression while the biogenic amines stachydrine and trigonelline acted as inhibitors of EpRE-mediated gene expression at 100 μM. The identification of glucolepidiin, glucobrassicin, glucocapparin, stachydrine, and trigonelline in all extracts was confirmed using standards and based on multiple reaction monitoring; yet, glucobrassicin level in the root extract was negligible. In conclusion, this study provided a first report on EpRE mediated gene expression effects of M. subcordata; and despite detection of different glucosinolates in all extracts, those containing glucobrassicin particularly displayed high EpRE induction. Because EpRE inducers are cytoprotective and potential chemopreventive agents while inhibitors are suggested adjuvants of chemotherapy, results of this study imply that process manipulation of this plant may result in herbal preparations that may be used as chemopreventive agents or adjuvants of chemotherapies.

Anti-nociceptive effect of methanol extract of leaves of Senna singueana in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Senna singueana (Del.) Lock (Fabaceae) is a shrub or tree found in Ethiopia and other African countries. It has been traditionally used for different conditions including treatment of pain conditions in humans and animals. Although various reports are available in the literature claiming different activities of the plant, scientific studies supporting analgesic potential of S. singueana are lacking and the present study aimed to investigate the antinociceptive effect of methanol extract of leaves of S. singueana in mice.

MATERIALS AND METHODS

Anti-nociceptive activity of S. singueana (200 mg/kg and 400 mg/kg, p.o) was investigated using acetic acid-induced writhing, formalin-induced paw licking, and hot plate tests. Acute oral toxicity was determined using a slightly modified guideline (423) of the Organization for Economic Cooperation and Development.

RESULTS

S. singueana extract increased the percentage of inhibition of writhing response and licking response (neurogenic and inflammatory phase) in acetic acid-induced writhing and formalin-induced paw licking tests, respectively. It also significantly (p ≤ 0.05) increased the percentage of mean maximal effect (%MPE) compared to control group in the hot-plate test. In all models, the combination of S. singueana with either diclofenac or morphine produced statistically significant increase (p ≤ 0.05) in the percentage of inhibition of writhing, paw licking, and %MPE compared to single treatment groups. It was also found that the 400 mg/kg extract produced higher antinociceptive effects (p ≤ 0.05) compared to the 200 mg/kg.

CONCLUSION

S. singueana leaves may have analgesic effect that is mediated through both peripheral and central mechanisms and could be used as adjuvant treatment to the modern analgesics.

Evaluation of Senna singueana leaf extract as an alternative or adjuvant therapy for malaria

The emergence of malarial resistance to most antimalarial drugs is the main factor driving the continued effort to identify/discover new agents for combating the disease. Moreover, the unacceptably high mortality rate in severe malaria has led to the consideration of adjuvant therapies. Senna singueana leaves are traditionally used against malaria and fever. Extracts from the leaves of this plant demonstrated in vitro and in vivo antioxidant activities, which in turn could reduce the severity of malaria. Extracts from the root bark of this plant exhibited antiplasmodial activity; however, the leaves are the more sustainable resource. Thus, S. singueana leaf was selected for in vivo evaluation as a potential alternative or adjuvant therapy for malaria. Using malaria [Plasmodium berghei ANKA, chloroquine (CQ) sensitive]-infected Swiss albino mice of both sexes, 70% ethanol extract of S. singueana leaves (alone and in combination with CQ) was tested for antimalarial activity and adjuvancy potential. The 4-day suppressive test was used to evaluate antimalarial activity. The dose of S. singueana extract administered was safe to mice and exhibited some parasite suppression effect: extract doses of 200 mg/kg/d, 400 mg/kg/d, and 800 mg/kg/d caused 34.54%, 44.52%, and 47.32% parasite suppression, respectively. Concurrent administration of the extract with CQ phosphate at varied dose levels indicated that the percentage of parasite suppression of this combination was higher than administering CQ alone, but less than the sum of the effects of the extract and CQ acting separately. In conclusion, the study indicated that 70% ethanol extract of S. singueana leaf was safe to mice and possessed some parasite suppression effect. Coadministration of the extract with CQ appeared to boost the overall antimalarial effect, indicating that the combination may have a net health benefit if used as an adjuvant therapy.