Comparative study of antipyretic potency of extracts of morinda lucida leaves and fruits of capsicum frutescens in albino rats.

Background: Morinda lucida leaves and fruits of Capsicum frutescens are used locally in the management of fever in Nigeria. No scientific credence has been lent to this claim. Objective: To investigate the antipyretic effect and potency of aqueous extracts of Morinda lucida leaves and fruits of Capsicum frutescens in albino rats. Method: Brewer's yeast was used to induce pyrexia. Thirty animals were divided into six groups. Group A was orally administered normal saline (103 mg/kg). Group B was served indomethacin (5 mg/kg), while groups C and D received aqueous extract of Capsicum frutescens at 100mg/kg and 200mg/kg, 17 hours post induction of pyrexia. Groups E and F were administered extract of Morinda lucida at the same doses. Rectal temperature of the animals was taken at 60-, 90- and 120-minutes post-treatment. Results: Both C. frutescens and M. lucida produced significant reduction (p<0.05) in rectal temperature after 120 minutes in the rats compared with animals in the control group. Also, the antipyretic activities of the two extracts at 100mg/kg and 200mg/kg were comparable to 5mg/kg of indomethacin, with apparent dose dependence in the antipyretic activities of both extracts. Conclusion: Morinda lucida leaves and fruits of Capsicum frutescens exhibit dose-dependent antipyretic activities.

Plasmodium berghei-induced malaria decreases pain sensitivity in mice.

Various types of pain were reported by people with Plasmodium falciparum and were mostly attributed to a symptom of malarial infection. Neural processes of pain sensation during malarial infection and their contributions to malaria-related death are poorly understood. Thus, these form the focus of this study. Swiss mice used for this study were randomly divided into two groups. Animals in the first group (Pb-infected group) were inoculated with Plasmodium berghei to induce malaria whilst the other group (intact group) was not infected. Formalin test was used to assess pain sensitivity in both groups and using various antagonists, the possible mechanism for deviation in pain sensitivity was probed. Also, plasma and brain samples collected from animals in both groups were subjected to biochemical and/or histological studies. The results showed that Pb-infected mice exhibited diminished pain-related behaviours to noxious chemical. The observed parasite-induced analgesia appeared to be synergistically mediated via µ-opioid, α2 and 5HT2A receptors. When varied drugs capable of decreasing pain threshold (pro-nociceptive drugs) were used, the survival rate was not significantly different in the Pb-infected mice. This showed little or no contribution of the pain processing system to malaria-related death. Also, using an anti-CD68 antibody, there was no immunopositive cell in the brain to attribute the observed effects to cerebral malaria. Although in the haematoxylin and eosin-stained tissues, there were mild morphological changes in the motor and anterior cingulate cortices. In conclusion, the pain symptom was remarkably decreased in the animal model for malaria, and thus, the model may not be appropriate for investigating malaria-linked pain as reported in humans. This is the first report showing that at a critical point, the malaria parasite caused pain-relieving effects in Swiss mice.

Bromelain reduced pro-inflammatory mediators as a common pathway that mediate antinociceptive and anti-anxiety effects in sciatic nerve ligated Wistar rats.

The involvement of pro-inflammatory mediators complicates the complex mechanism in neuropathic pain (NP). This study investigated the roles of bromelain against pro-inflammatory mediators as a mechanism that underpins its antinociceptive and anti-anxiety effects in the peripheral model of NP. Sixty-four male Wistar rats randomly divided into eight groups, were used for the study. A chronic constriction injury model of peripheral neuropathy was used to induce NP. Tail-immersion and von Frey filaments tests were used to assess hyperalgesia while open field and elevated plus mazes were used to assess anxiety-like behaviour. NF-кB, iNOS, nitrate, and pro-inflammatory cytokines were investigated in the plasma, sciatic nerve, and brain tissues using ELISA, spectrophotometer, and immunohistochemistry techniques after twenty-one days of treatment. Bromelain significantly (p < 0.05) improved the cardinal signs of NP and inhibited anxiety-like behaviours in ligated Wistar rats. It mitigated the increases in cerebral cortex interleukin (IL) -1ß, IL-6, and PGE2 levels. Bromelain reduced NF-кB, IL-1ß, IL-6, TNF-α, PGE2, and nitrate concentrations as well as the expression of iNOS in the sciatic nerve. Hence, the antinociceptive and anxiolytic effects of bromelain in the sciatic nerve ligation model of NP is in part due to its ability to reduce nitrosative and inflammatory activities.

Diabetic neuropathy is associated with increased pain perception, low serum beta-endorphin and increase insulin resistance among Nigerian cohorts in Ekiti State.

INTRODUCTION: There has been an increase in the global prevalence of diabetic polyneuropathy and research evidence suggests that insulin resistance plays an important role in its development and prognosis. However, there seem to be a dearth of information in understanding the likely interplay between beta endorphin, insulin resistance and pain perception especially in the setting of painful diabetic neuropathy. METHOD: This study recruited 120 volunteers divided into four groups (30 per group): group 1 healthy volunteer (control); group 2 DM type 2 without neuropathy (DM group); group 3 DM type 2 with painful neuropathy (DPN group); group 4 DM type 2 without painful neuropathy (DN). All subjects were evaluated for pain threshold and neuropathy using an ischemia-induced pain model and biothesiometer respectively. Their beta-endorphin, glycated hemoglobin, fasting plasma insulin, and HOMA values were determined and means compared using ANOVA. RESULT: Serum beta-endorphin is significantly reduced in DN and DPN (∗p < 0.001) compared with the control and DM group. Also, DPN and DN patients have significantly increased insulin resistance compared to those without neuropathy (∗p < 0.001; ∗p < 0.0001 respectively). There is a significant positive correlation between the pain threshold and beta-endorphin in all the groups except DN group. The correlation between beta-endorphin and insulin resistance was negative and significant in control and DM groups only. Suggestive that the fact that insulin resistance plays an important role in diabetes polyneuropathy, does not alone explain the chronic pain perception noticed in the DPN patients. CONCLUSION: The present study demonstrates that diabetic neuropathy patients have a poor endogenous opioid peptide system which is associated with increased pain perception and high insulin resistance. However, insulin resistance alone does not explain the chronic pain perception noticed in the DPN patients. Thus, further study is required.

Analgesic properties of aqueous bark extract of Adansonia digitata in Wistar rats.

The study investigated the analgesic effect of the aqueous extract of the bark of Adansonia digitata using Wistar rats. Thirty Wistar rats weighing between 150 and 170g of either sex were used for the study. Animal were picked randomly and grouped into six with each group made up of five animals (3 females and 2 males). Oral administration of 10ml/kg of normal saline were given to control group; 5mg/kg of indomethacin to reference group; and 25mg/kg, 50mg/kg, 100mg/kg or 200mg/kg of aqueous extracts of Adansonia digitata to each of the test groups respectively.Hotplate and formalin paw-licking tests were used for nociceptive assessment. Animals treated with aqueous bark extract of Adansonia digitata showed significantly (p<0.05) prolonged response time to thermal stimuli (4.42±0.11s) compared with control group (3.29±0.29s) in a dose dependent manner. Results formalin paw-licking test showed that at early phase, animals administered with aqueous bark extract of Adansonia digitata significantly (p<0.05) have reduced paw-licking time (47.88±3.48-40.80±3.85s) compared with the control group (91.51±7.32s). In the late phase, aqueous bark extract of Adansoni adigitata significantly (p<0.05) reduced the paw-licking time (43.57±2.6-25.49±3.46s) compared with the control group (66.31±5.04s). It is hereby concluded that aqueous bark extract of A. digitata possesses a strong analgesic effect.

Anti-inflammatory and antipyretic properties of Corchorus olitorius aqueous root extract in Wistar rats.

BACKGROUND: This study was designed to provide information about the antipyretic and anti-inflammatory effects of Corchorus olitorius root. METHODS: Thirty male Wistar rats were divided into six groups of five animals each; the control and reference groups were administered normal saline (10 mL/kg) and indomethacin (5 mg/kg), respectively, whereas the remaining four groups were administered aqueous extract of C. olitorius at doses of 25, 50, 100, or 200 mg/kg, respectively. Pyrexia was induced by injecting 10 mL/kg of 20% (w/v) brewer's yeast suspension into the dorsum of rats, whereas inflammation was induced through an injection of 0.1% carrageenan into the right hind paw of each rat and through a subcutaneous implantation of a 30-g sterilized cotton pellet into the groin of each rat. RESULTS: The results showed that C. olitorius root extract (p<0.05) decreased the elevated temperature after brewer's yeast injection compared with the 17 h (pre-drug) temperature. In the inflammatory tests, the paw sizes and granuloma weights in the test groups were significantly (p<0.05) decreased compared with the control group. CONCLUSIONS: Corchorus olitorius root is another good source of phytomedicine that can be used effectively to treat inflammation and pyrexia that accompany some diseases.

Analgesic and anti-inflammatory effects of aqueous extract of Zea mays husk in male Wistar rats.

The analgesic and anti-inflammatory activities of Zea mays husk extract (25, 50, 100, and 200 mg/kg of body weight) were investigated in rats. The hot plate and formalin-induced paw licking models were used to assess analgesic effects of the extract, whereas the carrageenan and cotton pellet models were used for the evaluation of anti-inflammatory activity. The extract at 25, 50, 100, and 200 mg/kg body weight significantly (P < .05) reduced pain stimuli and inflammatory activity when compared with the control group. The reductions in paw licking time and granuloma weight in the formalin and cotton pellet models were both dose dependent. Also, the 200 mg/kg doses of the extract produced higher effects compared with indomethacin (5 mg/kg body of weight) in all the tests. These observations suggest that Z. mays husk extract may have analgesic and anti-inflammatory effects that may be due to its tannins and polyphenolic constituents. These results provide scientific validation for the use of Z. mays husk decoction for the treatment of pain and inflammatory conditions in Nigerian folk medicine.

Studies on the analgesic, anti-inflammatory and antipyretic effects of Parquetina nigrescens leaf extract.

ETHNOPHARMACOLOGICAL RELEVANCE: Parquetina nigrescens is a shrub that is commonly used in different parts of West Africa for the treatment of several ailments which includes pain, fever and inflammatory conditions. AIM OF THE STUDY: The present study was designed to investigate the analgesic, anti-inflammatory and antipyretic effects of the aqueous extract of Parquetina nigrescens leaves in rats. MATERIALS AND METHODS: Five groups were used for each study, groups 1 and 5 served as control (saline) and reference (indomethacine) respectively, while groups 2-4 received the extract (50-200 mg/kg) orally. Formalin paw licking and hot plate latency tests were used for analgesic studies. Carrageenan oedema, cotton pellet granuloma and formaldehyde arthritis models were used to quantify the anti-inflammatory activities while the brewer's yeast was used for inducing pyrexia. RESULTS: The results of the analgesic study show that the extract produced significant (p<0.05) analgesia in the hot plate and in the formalin tests. In the anti-inflammatory study, Parquetina nigrescens produced significant (p<0.05) inhibition of the various types of inflammation. The extract also inhibited the pyrexia induced by brewer's yeast. CONCLUSION: The result justifies the traditional uses of Parquetina nigrescens for the treatment of fever, inflammatory and painful conditions.

Anti-inflammatory activities of ethanolic extract of Carica papaya leaves.

The anti-inflammatory activity of an ethanolic extract of Carica papaya leaves was investigated in rats using carrageenan induced paw oedema, cotton pellet granuloma and formaldehyde induced arthritis models. Experimental animals received 25-200 mg/Kg (orally) of the extracts or saline (control group) and the reference group received 5 mg/ Kg of indomethacin. The ulcerogenic activity of the extract was also investigated. The results show that the extracts significantly (p <0.05) reduced paw oedema in the carrageenan test. Likewise the extract produced significant reduction in the amount of granuloma formed from 0.58 +/-0.07 to 0.22 +/-0.03 g. In the formaldehyde arthritis model, the extracts significantly reduced the persistent oedema from the 4th day to the 10th day of the investigation. The extracts also produced slight mucosal irritation at high doses. The study establishes the anti-inflammatory activity of Carica papaya leaves.