RESUMO
Introduction: Waltheria indica Linn (Malvaceae) is a widely distributed plant in West Africa. It is commonly used in Burkina Faso to treat inflammation-related diseases, including asthma. Previous reviews have focused on the ethnobotanical, traditional uses, phytochemistry, and pharmacological properties of Waltheria indica. This report aims to compile the biological and pharmacological activities that highlight the anti-asthmatic properties of Waltheria indica L. (W. indica). Method: Electronic databases, such as PubMed, Scopus, Hinari, SciFinder, Google Scholar, and ScienceDirect, were used to gather data on Watheria indica. Data on the toxicological, anti-inflammatory, antioxidant, and bronchorelaxant effects of W. indica were collected. Results: Twenty-three studies describing the biological and pharmacological activities relevant to assessing the anti-asthmatic properties of W. indica were found. Nine articles investigated the anti-inflammatory effects, and three manuscripts were found to have bronchorelaxant activity. Five publications reported the antioxidant activity of the plant extracts. Research on the extracts revealed a tolerable safety profile in rats and mice with an LD50 ranging from 300 to 5000 mg/kg body weight, depending on the parts of the plant used. Phenolic compounds, particularly flavonoids, alkaloids, and saponins, were found to be responsible for the activities involved in the assessment of anti-asthmatic properties. Conclusion: The results of this review suggest that W. indica could be a valuable resource for the treatment of asthma and other respiratory diseases. However, further chemical and pharmacological investigations are needed to understand its mechanism of action in treating asthma.
RESUMO
Waltheria indica L. (Malvaceae) is a plant used in Burkina Faso for the treatment of various ailments including asthma. The aim of the study was to evaluate the pharmacological relaxant effect of the leafy stem extracts of Waltheria indica and thereby verify claim of use in treating asthma. Aqueous decoction and hydroalcoholic extracts obtained from the powdered leafy stems were screened for the presence of some phytoconstituents. The in vitro relaxant effect of the two extracts was evaluated on acetylcholine- (ACh 10-5 M) and potassium chloride- (KCl 6 × 10-2 M) induced contractions on rat-isolated tracheal preparations. To examine whether the potassium (K+) channels are involved in the relaxant effect, glibenclamide, an ATP-sensitive potassium channel inhibitor, was used. Moreover, to assess the safety of the extracts, acute oral toxicity was carried out on mice. The phytochemical screening revealed the presence of alkaloids, flavonoids, saponins, steroids, triterpenoids, tannins, and coumarins in the hydroalcoholic extract. Tannins, steroids, triterpenoids, and coumarins were not detected in the aqueous decoction. With respective EC50 values of 1.517 ± 0.002 mg/mL and 1.433 ± 0.001 mg/mL on ACh-and KCl-provoked contractions, the hydroalcoholic extract was found more potent in relaxing the isolated rat tracheal preparations compared to the aqueous decoction. In the presence of glibenclamide, the relaxant effect of the hydroalcoholic extract (EC50 = 0.191 ± 0.002 mg/mL) increased and was higher than that of the aqueous decoction. At dose of 5000 mg/kg of body weight, the extracts did not produce deaths or any significant changes in the general behavior of mice. The results suggest that different mechanisms including modulation of calcium and potassium channels, particularly the ATP-sensitive K+ channels, could be involved in the relaxation effect. These findings could justify the traditional use of W. indica in the management of asthma.
