Maerua angolensis Extract Reduces Allodynia and Hyperalgesia in a Mouse Model of Vincristine-Induced Peripheral Neuropathy

Intestinal anti-inflammatory and visceral analgesic effects of a Serpylli herba extract in an experimental model of irritable bowel syndrome in rats

Ethnopharmacological relevance:Serpylli herba extract (SHE), composed of the aerial parts of wild thyme (Thymus serpyllum L.) (Lamiaceae family), is traditionally used in Europe and North Africa to treat diarrhea, gastric ulcers, intestinal parasites and upper respiratory tract infections. Recently, SHE has generated a great interest for irritable bowel syndrome (IBS) management, probably due to its intestinal anti-inflammatory properties shown in experimental colitis and the fact that its active components could preserve the intestinal barrier integrity, which is altered in patients with IBS.

Aim of study: We aimed to test the effects of a SHE in a rat experimental model resembling human IBS.

Materials and methods: IBS was provoked by deoxycholic acid (DCA). Rats were then treated with SHE (100 mg/kg) or gabapentin (70 mg/kg) and different inflammatory and gut barrier integrity markers were evaluated. Moreover, several gut hypersensitivity and hyperalgesia determinations were performed.

Results: SHE improved referred pain and visceral hypersensitivity. Additionally, SHE enhanced immune status by downregulating of the expression of the pro-inflammatory mediators Il-1β, Il-6, Ifn-γ, Tlr-4, and the inducible enzyme Cox-2, thus inducing visceral analgesia, and promoting the restore of the gut barrier function by upregulating the mucins Muc-2 and Muc-3. These anti-inflammatory effects could be related to its action on mast cells since it significantly inhibited the β-Hexosaminidase production in RBL-2H3 cells. Lastly, SHE also seems to modulate the serotonin pathway by restoring the altered expression of the 5-HT receptors Htr-3 and Htr-4.

Conclusion: SHE could be considered a potential new treatment for IBS, since it ameliorates hypersensitivity, visceral hyperalgesia, and inflammation. These beneficial effects may be due to the inhibition of mast cells degranulation and serotonin pathway.

Hydroethanolic Stem Bark Extract of Burkea africana Attenuates Vincristine-Induced Peripheral Neuropathy in Rats

Context. The stem bark of the savanna tree Burkea africana (Hook) (family: Leguminosae) is used in the Ghanaian traditional medicine for the management of various pain-related diseases.

Medicinal plants and their isolated phytochemicals for the management of chemotherapy-induced neuropathy: therapeutic targets and clinical perspective

BACKGROUND

Chemotherapy, as one of the main approaches of cancer treatment, is accompanied with several adverse effects, including chemotherapy-induced peripheral neuropathy (CIPN). Since current methods to control the condition are not completely effective, new treatment options should be introduced. Medicinal plants can be suitable candidates to be assessed regarding their effects in CIPN. Current paper reviews the available preclinical and clinical studies on the efficacy of herbal medicines in CIPN.

METHODS

Electronic databases including PubMed, Scopus, and Cochrane library were searched with the keywords "neuropathy" in the title/abstract and "plant", "extract", or "herb" in the whole text. Data were collected from inception until April 2018.

RESULTS

Plants such as chamomile (Matricaria chamomilla L.), sage (Salvia officinalis L.), cinnamon (Cinnamomum cassia (L.) D. Don), and sweet flag (Acorus calamus L.) as well as phytochemicals like matrine, curcumin, and thioctic acid have demonstrated beneficial effects in animal models of CIPN via prevention of axonal degeneration, decrease in total calcium level, improvement of endogenous antioxidant defense mechanisms such as superoxide dismutase and reduced glutathione, and regulation of neural cell apoptosis, nuclear factor-ĸB, cyclooxygenase-2, and nitric oxide signaling. Also, five clinical trials have evaluated the effect of herbal products in patients with CIPN.

CONCLUSIONS

There are currently limited clinical evidence on medicinal plants for CIPN which shows the necessity of future mechanistic studies, as well as well-designed clinical trial for further confirmation of the safety and efficacy of herbal medicines in CIPN. Graphical abstract Schematic mechanisms of medicinal plants to prevent chemotherapy-induced neuropathy: NO: nitric oxide, TNF: tumor necrosis factor, PG: prostaglandin, NF-ĸB: nuclear factor kappa B, LPO: lipid peroxidation, ROS: reactive oxygen species, COX: cyclooxygenase, IL: interleukin, ERK: extracellular signal-related kinase, X: inhibition, ↓: induction.

Maerua angolensis DC. (Capparaceae) Stem Bark Extract Protects against Pentylenetetrazole-Induced Oxidative Stress and Seizures in Rats

Introduction

The stem bark of Maerua angolensis DC. (Capparaceae) is traditionally used for management of epilepsy. Our aim was to evaluate the antiseizure potential and identify possible mechanisms by which the effects are registered.

Methods

The petroleum ether/ethyl acetate extract (100–1000 mg kg⁻¹) was administered per os to male Sprague-Dawley rats after pretreatment with flumazenil (0.3 mg kg⁻¹) or L-arginine (150 mg kg⁻¹) or sildenafil (5 mg kg⁻¹) and they subsequently received a subcutaneous injection of pentylenetetrazole (65 mg kg⁻¹). Rats were observed for latency to and duration of myoclonic seizures and additionally the level of protection against oxidant markers and products was assessed in vitro and in vivo.

Results

The extract (300 and 1000 mg kg⁻¹, p.o.) significantly delayed the onset and decreased the duration and frequency of PTZ-induced convulsions. The anticonvulsant effect of MAE (300 mg kg⁻¹, p.o.) was reversed by pretreatment with flumazenil, L-arginine, or sildenafil. Also, MAE (300 mg kg⁻¹) treatment reversed significantly PTZ-induced oxidative stress in rat brain tissue.

Conclusion

The petroleum ether/ethyl acetate fraction exhibits antiseizure activity by affecting GABAergic and nitric oxide-cGMP pathways. In addition, the extract protects against the generation of free radicals and the oxidative products of the PTZ-induced seizures.

Antinociceptive effectiveness of Tithonia tubaeformis in a vincristine model of chemotherapy-induced painful neuropathy in mice

BACKGROUND

Chemotherapy induced peripheral neuropathy (CIPN) is a painful side-effect of commonly used chemotherapeutic agents that profoundly impair the quality of life of patients as the current pharmacotherapeutic strategies are inefficient in providing adequate pain relief. Complementary and alternative medicine (CAM) therapies are preferred by patients with neuropathic pain as they experience insufficient control of pain with conventional medications. This study describes the antinociceptive effect of Tithonia tubaeformis (Jacq.) Cass. in a vincristine mouse model of established CIPN.

METHODS

Tithonia tubaeformis hydromethanolic extract was tested for preliminary qualitative phytochemical analysis and acute oral toxicity test in mice. The antinociceptive effect was investigated using the abdominal constriction (writhing) and tail immersion tests (25-200 mg/kg). The anti-neuropathic effect was determined in the vincristine mouse model, established by daily administration of vincristine (0.1 mg/kg/day, i.p) for consecutive 14 days. Acute treatment with Tithonia tubaeformis (100 and 200 mg/kg) and the positive control, gabapentin (75 mg/kg) was carried out on the 15th day of the last vincrsitine dose and the animals were tested for allodynia and thermal hyperalgesia at 30-120 min post extract/drug administration.

RESULTS

Vincristine produced significant temporal tactile allodynia and thermal hyperalgesia (P < 0.01 and P < 0.001 on day 7 and 14) and was maintained for the subsequent day (P < 0.001 during 30-120 min). Tithonia tubaeformis was effective in attenuating the vincristine-induced allodynia and thermal hyperalgesia at 100 mg/kg (P < 0.05, P < 0.01) and 200 mg/kg (P < 0.01, P < 0.001). Similarly, gabapentin also showed a robust antinociceptive effect in counteracting the vincristine associated behavioral alterations.

CONCLUSIONS

Tithonia tubaeformis can be an effective CAM therapeutic remedy for established CIPN due to its potential antinociceptive effect in attenuating vincristine-induced neuropathy.