Anti-inflammatory and anti-oxidant activities of ethanolic extracts of Tamarindus indica L. (Fabaceae)

Abstract

Various parts of Tamarindus indica L are used to treat inflammatory disorders. This study evaluated the anti-inflammatory and antioxidant activities of the ethanolic extracts of the root and stem bark of the plant. The carrageenan-induced paw edema model of inflammation in chicks was used to assess anti-inflammatory activity. The phosphomolybdenum (PM) assay, 2, 2—diphenyl—1—picrylhydrazyl (DPPH) radical and hydrogen peroxide scavenging assays were used to investigate antioxidant potential. Total phenolic content was evaluated by the Folin–Ciocalteu method. Both stem bark and root extracts possessed similar total phenolic content (11–13 g/100 g AAE) and had comparable total antioxidant capacities (about 27 g/100 g GAE). However, the stem bark extract was a better scavenger of both DPPH radicals and hydrogen peroxide, with lower IC₅₀ values than the root extract. In the anti-inflammation test, both extracts exhibited dose-dependent reduction of edema, similar to the standard drugs used. The root extract, with ED₅₀ of 118.1 ± 1.9 mg/kg, proved superior to the stem bark extract, whose ED₅₀ was 154.5 ± 2.6 mg/kg. The results showed that both stem bark and root extracts possess potent anti-inflammatory and anti-oxidant activity and confirm their use in folkloric medicine.

Keywords:

• herbal plant validation
• carrageenan-induced paw edema
• total antioxidant capacity
• phosphomolybdenum assay
• inflammation

PUBLIC INTEREST STATEMENT

Tamarindus indica L, (tamarind) is a common plant in West Africa and parts of Asia. Known as yooyi in Ga (a Ghanaian language), the different parts of the plant are used for various purposes in traditional herbal medicine. The seeds are used in the treatment of chronic diarrhea and dysentery. The roots and bark are used as remedies for treating ulcers, boils, rashes, eye and skin inflammation, indigestion and to promote wound healing. The leaves and flowers of the plant are also used to treat swollen joints, boils and sprains. This research work was undertaken to provide a scientific validation for the use of the plant in herbal medicine. The results of the study show that ethanol extracts of the root and stem bark of the plant are very good in reducing inflammation and neutralizing free radicals.

Acknowledgements

Authors acknowledge support from the Departments of Chemistry and Pharmacology, all in KNUST, whose facilities were used for this study. Mr. Gyan, Bernard Ussher and Michael Konney Laryea, all of KNUST and Inusah Issah of the Department of Chemical Sciences, University of Energy and Natural Resources, Sunyani – Ghana provided technical support and are duly acknowledged.

Competing Interests

The authors declare that there were no competing financial, professional, or personal interests that might have influenced the performance or presentation of the work described in this manuscript.

Author Contributions

The study was conceived by LSB. All experiments were designed by LSB and MSD. Plant collection and all experimental procedures were done by MSD, SOB and JAM. The data were analyzed MSD, SOB, JAM and LSB. The initial manuscript was drafted by LSB. All authors read and approved the final manuscript.

Ethics

The project proposal and procedures were reviewed and approved by the Institution Ethics Review Board for Animal Use at the Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.

Data availability

All data generated or analyzed during this study are included in this published article.

Additional information

Funding

No direct funding was received for this research. The rotary evaporator used for the study was purchased with an International Foundation for Science (IFS) Collaborative Research Grant to LSB.

Notes on contributors

Lawrence Sheringham Borquaye

Lawrence Sheringham Borquaye is a bioorganic chemist at the Department of Chemistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana and leader of the Borquaye Research Group. His research focuses on science at the interface of chemistry and biology. He has been exploring biologically active natural products from plants and marine organisms. Other research interests include the development of methods for the analysis of pharmaceutical and personal care products in the environment and the characterization of volatile (essential oils) from plant sources. Michel Selassie Doetse, Samuel Ofori – Baah and Jennifer Amo – Mensah were undergraduate Chemistry students who did their final year projects in the Borquaye Research Group. Visit us at www.borquayelab.com for more information about our research group.