Leaves and stems of Capparis erythrocarpos, more sustainable than roots, show antiarthritic effects

ETHNOPHARMACOLOGICAL RELEVANCE

Capparis erythrocarpos is a medicinal plant used widely in many parts of Africa for the management of pain and inflammatory conditions such as rheumatoid arthritis. Its wide range of use, popularity and high value, make C. erythrocarpos containing products a target for economically driven adulteration. This is made worse, by the use of roots, which are unsustainable plant parts. In addition, the mechanism of anti-inflammation is not clearly understood.

AIM OF THE STUDY

Therefore, this study comparatively evaluated the anti-arthritic and analgesic effects of the leaves, stems and roots of C. erythrocarpos, while elucidating the mechanism of anti-inflammation.

MATERIALS AND METHODS

Using the complete Freund's adjuvant arthritis model, the antiathritic effects were evaluated. The analgesic effects were determined by measuring responses to Von Frey filament number 9. Effects of C. erythrocarpos extracts on the levels of Interleukin-6 (IL-6) and Tumor Necrosis Factor-alpha (TNF-α) were determined using ELISA. Haematological and serum biochemical assays were also carried out.

RESULTS

The leaf, stem and root extracts significantly reduced paw volumes with ED₅₀ values (mg/kg) of 182.5, 181.5 and 36.4 respectively. The leaf extract at a dose of 100 mg/kg showed substantial analgesic activity with a decrease in the percentage response to Von Frey filament 9. However, there was no significant difference in activities of the leaf, stem and root extracts. Results from ELISA assays show that lower doses of the stem extracts reduce levels of IL-6. Lower doses of all extracts also reduce TNF-α levels. Haematological analysis showed extracts reversed elevated WBC and platelet levels. Toxicity evaluation with kidney and liver function tests indicated no significant differences between the treatment and control groups.

CONCLUSIONS

The leaves and stems, just as the roots, have antiarthritic and analgesic effects and can be used as more sustainable alternatives to the roots. This will support the continuous growth of the industry that has developed around C. erythrocarpos.

Antiinflammatory properties of betulinic acid and xylopic acid in the carrageenan-induced pleurisy model of lung inflammation in mice

This study investigated the antiinflammatory properties of betulinic acid (BA) and xylopic acid (XA) extracted from Margaritaria discoidea and Xylopia aethiopica, respectively. M. discoidea and X. aethiopica are plants native in Ghana and the West-African region and used traditionally to treat different pathologies including inflammatory conditions. The antiinflammatory effect of BA and XA was established by an in vivo assay using the carrageenan-induced pleural inflammation model in mice. Also, the ability of BA and XA to increase catalase, superoxide dismutase, glutathione levels and decrease lipid peroxidation level in reactive oxidative assays was assessed. In addition, the ability of XA and BA to prevent potential lung tissue damage was quantified. Pretreatment with BA and XA reduced significantly, signs of inflammation: neutrophil infiltration, oedema, and alveoli septal thickening in carrageenan-treated lung tissue. Additionally, BA or XA pretreatment lowered the degree of lipid peroxidation in the lung tissue while increasing the levels of catalase, superoxide dismutase, and glutathione in vivo. Comparatively, XA was more efficacious than BA in the prevention of lung tissue damage. BA and XA derived from X. aethiopica and M. discoidea possess antiinflammatory and in vivo antioxidant activities in mice pleurisy model. The effect of these compounds gives credence to the traditional use in the management of inflammatory conditions of the airway.

Anticonvulsant activity of Pseudospondias microcarpa (A. Rich) Engl. hydroethanolic leaf extract in mice: The role of excitatory/inhibitory neurotransmission and nitric oxide pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Pseudospondias microcarpa (A. Rich) Engl. is a plant used for managing various diseases including central nervous system disorders.

AIM OF THE STUDY

This study explored the anticonvulsant activity of P. microcarpa hydroethanolic leaf extract (PME) as well as possible mechanism(s) of action in animal models.

METHODS

Effects of PME was assessed in electroconvulsive (the maximal electroshock and 6-Hz seizures) and chemoconvulsive (pentylenetetrazole-, picrotoxin-, isoniazid-, 4-aminopyridine-, and strychnine-induced seizures) models of epilepsy. In addition, effect of the extract on the nitric oxide pathway and GABA_A receptor complex was evaluated.

RESULTS

The extract (30, 100 and 300mgkg^-1, p.o.) significantly delayed the onset as well as decreased the duration and frequency of pentylenetetrazole-, picrotoxin- and strychnine-induced seizures. In addition, PME pre-treatment significantly improved survival in the 4-aminopyridine- and isoniazid-induced seizure tests. Furthermore, the extract protected against 6-Hz psychomotor seizures but had no effect in the maximal electroshock test. The anticonvulsant effect of PME (100mgkg^-1, p.o.) was also reversed by pre-treatment with flumazenil, L-arginine or sildenafil. However, L-NAME or methylene blue (MB) augmented its effect.

CONCLUSION

Results show that PME has anticonvulsant activity and may probably be affecting GABAergic, glycinergic, NMDA, K⁺ channels and nitric oxide-cGMP pathways to exert its effect.

Xylopia aethiopica fruit extract exhibits antidepressant-like effect via interaction with serotonergic neurotransmission in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Xylopia aethiopica has been used traditionally to treat some central nervous system disorders including epilepsy.

AIM OF THE STUDY

Despite the central analgesic and sedative effects, there is little evidence for its traditional use for CNS disorders. This study thus assessed the antidepressant potential of Xylopia aethiopica ethanolic fruit extract (XAE).

MATERIAL AND METHODS

Antidepressant effect was assessed in the forced swim test (FST) and tail suspension test (TST) models in mice. The role of monoamines in the antidepressant effects of XAE was evaluated by selective depletion of serotonin and noradrenaline, whereas involvement of NMDA/nitric oxide was assessed with NMDA receptor co-modulators; d-serine and d-cycloserine and NOS inhibitor, l-NAME.

RESULTS

Xylopia aethiopica (30, 100, 300mgkg(-1)) dose dependently reduced immobility in both FST and TST. The reduced immobility was reversed after 5-hydroxytryptamine (5-HT) depletion with tryptophan hydroxylase inhibitor-p-chlorophenylalanine (pCPA) and after monoamine depletion with vesicular monoamine transporter inhibitor-reserpine. The observed antidepressant effect was not affected by catecholamine depletion with the tyrosine hydroxylase inhibitor, α-methyl-p-tyrosine (AMPT). Similarly XAE did not potentiate the toxicity of a sub-lethal dose of noradrenaline. XAE had a synergistic effect with the glycineB receptor partial agonist, d-cycloserine and nitric oxide synthase inhibitor, l-NAME. However established antidepressant effects of XAE were abolished by NMDA and NOS activation with d-serine and l-arginine.

CONCLUSION

This study shows that Xylopia aethiopica has antidepressant potential largely due to effects on 5-HT neurotransmission with possible glutamatergic effect through the glycineB co-binding site and nitric oxide synthase inhibition.