Background & Aims

Muscle pain is a debilitating condition that affects approximately 47% of the general population. For decades, its management has remained a challenge with often deceiving therapeutic results especially, in chronic cases. For greater efficacy, new treatment alternatives require multimodal analgesics and herbal medicine appears as a promising source. Psychotria camptopus methanol extract has demonstrated beneficial effects in neurological and inflammatory diseases. We hypothesized that it may be active against muscular pain. Thus, we investigated the preventive and curative antinociceptive effects of the methanol extract from the stem bark of Psychotria camptopus (MEPC) on acute and chronic muscle pain in mice.

Methods

MEPC obtained by maceration was administered orally at 40, 80, and 120 mg/kg against acute muscle pain induced by intramuscular injection of 2.5% formalin. The injected paw’s lifting, licking and shaking time was recorded during the first two hours post-induction. In the chronic curative experiment, the pain was induced by injecting the left gastrocnemius with lipopolysaccharides (LPS, 2 µg/kg) followed 24 h later by the injection of a hypertonic saline solution (NaCl, 6%). MEPC was given orally once a day at the doses mentioned above, starting one hour after the induction. Mechanical hyperalgesia (analgesimeter on injected muscle) was measured before and at 1, 3, 7, 11, and 15 days post-induction. Tactile allodynia (von Frey hair on the paw) was evaluated before and at days 1, 5, 9, 13, and 17 post-induction. At the end of the observation period, animals were sacrificed. Brain hemispheres, spinal cord, and the injected muscle were collected for MDA, SOD, NO, and MPO assays

Results

In the acute test, MEPC inhibited pain-like behavior in a dose-dependent manner, with a significant (p<0.05) effect observed at doses of 80 and 120 mg/kg. In the chronic test, repeated administration of MEPC led to a significant (p<0.001) time-dependent reduction of hyperalgesia and allodynia. MEPC significantly (p<0.001) reduced malondialdehyde levels in the left brain hemisphere and in the muscle but not in the spinal cord and the right brain hemisphere. MEPC increased muscle superoxide dismutase content and reversed myalgia-induced nitric oxide increase in both hemispheres but tended to increase the level of the latter in the spinal cord. MEPC also reduced myeloperoxidase activity in the injected muscle.

Conclusions

These results suggest that Psychotria camptopus methanol extract is a potent candidate for the treatment of both acute and chronic muscle pain. These effects might be related to its antioxidant and anti-inflammatory properties.

References

El-Tallawy SN, Nalamasu R, Salem GIK, LeQuang JA, Pergolizzi, JV, & Christo PJ. Management of Musculoskeletal Pain: An Update with Emphasis on Chronic Musculoskeletal Pain. Pain Therap. 2021;10(1): 181-209. https://doi.org/10.1007/s40122-021-00235-2
Fokoua AR, Ndjenda MK 2nd, Kaptué Wuyt A, Tatsinkou Bomba FD, Dongmo AK, Chouna R, Nkeng-Efouet PA, Nguelefack TB.Anticonvulsant effects of the aqueous and methanol extracts from the stem bark of Psychotria camptopus Verdc. (Rubiacaea) in rats. J Ethnopharmacol. 2021;272:113955. doi: 10.1016/j.jep.2021.113955.
Fokoua AR, Ajayi AM, Ben-Azu B, Chouna R, Folarin O, Olopade J, Nkeng-Efouet PA, Aderibigbe AO, Umukoro S, Nguelefack TB. The antioxidant and neuroprotective effects of the Psychotria camptopus Verd. Hook. (Rubiaceae) stem bark methanol extract contributes to its anti-epileptogenic activity against pentylenetetrazol kindling in male Wistar rats. Metab Brain Dis. 2021;36(7):2015-2027. doi: 10.1007/s11011-021-00825-1.

Presenting Author

Telesphore Bénoît Nguelefack

Poster Authors

Telesphore Bénoît NGUELEFACK

PhD

University of Dschang

Lead Author

E-mail

Cedric Koho Wamba

Msc

Research Unit of Neuro-inflammatory and Cardiovascular Pharmacology. Fac of Sciences. UDs. Cameroon.

Lead Author

E-mail

Roger Hermann Foguieng Sadie

Research unit of neuro-inflammatory and cardiovascular pharmacology, University of Dschang, Cameroon

Lead Author

E-mail

Bibiane Aimée WANDJI

Research unit of neuro-inflammatory and cardiovascular pharmacology, University of Dschang, Cameroon

Lead Author

E-mail

Judith Poualeu Manialeu

Research unit of neuro-inflammatory and cardiovascular pharmacology, University of Dschang, Cameroon

Lead Author

E-mail

Elvine Nguelefack-Mbuyo

Research unit of neuro-inflammatory and cardiovascular pharmacology, University of Dschang, Cameroon

Lead Author

E-mail

Topics

  • Models: Musculoskeletal