TITLE:
Acute Oral Toxicity and Vasorelaxant Effects of Hydroethanolic Extract from Lannea microcarpa Engl. & K. Krause (Anacardiaceae) Trunk Barks in Mice Aortas: Possible Involvement of Intracellular Ca 2+ Mobilization
AUTHORS:
Mathieu Nitiéma, Bertrand Kafando, Windingoudi Rimwagna Christian Ouédraogo, Bibata Sawadogo, Boukaré Kaboré, Wendkouni Leila Marie Esther Bélem-Kabré, Tata Kadiatou Traoré, Jean Claude Romaric Pingdwindé Ouédraogo, Salfo Ouédraogo, Lazare Belemnaba, Aristide Traoré, Moussa Ouédraogo, Noufou Ouédraogo, Bondo Félix Kini, Sylvin Ouédraogo
KEYWORDS:
Lannea macrocarpa, Hydroethanolic Extract, Phytoconstituents, Antioxidant, Vasorelaxant Effects, Safety
JOURNAL NAME:
Pharmacology & Pharmacy,
Vol.14 No.12,
December
29,
2023
ABSTRACT: Lannea microcrapa Engl. & K. Krause (Anacardiaceae) is a fruit and medicinal plant widely used
in Burkina Faso. This plant is traditionally used in the treatment of
hypertension. The aim of the present study was to evaluate the vasorelaxant
effects of the hydroethanolic extract from Lannea microcarpa trunk barks
(HE_ELM) on the aorta isolated from NMRI mice. Phytochemical screening by
HPTLC, assay of phenolic and flavonoid compounds, assessment of antioxidant activity
(DPPH, ABTS, FRAP, and LPO), and myography of HE_ELM (1 - 2000 μg/mL) on mice
thoracic aortas in the presence and absence of endothelium were carried out.
Endothelium-dependent and endothelium-independant vasodilation were assessed by cumulative addition of Ach (1 nM - 10
μM) on aortic rings precontracted with the thromboxane analogue A2 agonist,
9,11-dideoxy9α,11α-methanoepoxy PGF2α (U46619). L-NAME was used to verify the involvement of NO production in the
relaxation mechanism of the extract. Acute oral toxicity of HE_ELM was also
evaluated. A phytochemical study revealed the presence of tannins, flavonoids,
sterols and triterpenes, saponosides, and high levels of total phenolics and
flavonoids. These compounds are thought to be responsible for the extract’s
antioxidant and vasorelaxant properties. HE_ELM demonstrated significant
antioxidant potential and induced aortic relaxation. Indeed, pharmacological
parameters gave EC50 values ranging from 596.45 ± 95.82 μg/mL to
749.48 ± 133.40 μg/mL and Emax values from 85.51% ± 9.59% to 96.81% ± 8.60% for the three
conditions of vasodilation of the extract (p > 0.05). A complete antagonism
of the contractile effect of U46619 was noted with 1 mg/mL HE_ELM. These
results suggest that HE_ELM induces aortic relaxation through a
concentration-dependent, endothelium-independent mechanism, possibly involving
intracellular calcium mobilization of vascular cells. Acute oral toxicity tests
of HE_ELM (2000 mg/kg) showed no mortality or adverse effects, suggesting the
extract’s safety and potential as a therapeutic agent for hypertension. This
discovery scientifically validates the use of the plant in alternative medicine
to treat hypertension.