1. New flavonoids with multiple bronchodilator activity pathways from Tephrosia purpurea L. (Pers.) growing in Saudi Arabia.
- Author
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Abdel-Kader MS, Saeedan AS, Rehman NU, Faqihi HM, and Soliman GA
- Abstract
Total extract of Tephrosia purpurea ( T. purpurea ) expressed potent ex-vivo bronchodilator effect in isolated Guinea pigs' tracheal muscles. Fractionation of T. purpurea total extract ( TPTE) using liquid-liquid technique followed by ex-vivo bronchodilator testing indicated that the activity was trapped to the chloroform (CHCl
3 ) soluble fraction. Phytochemical study of the CHCl3 fraction guided by ex-vivo bronchodilator activity led to the isolation of 7 active flavones of which compounds 1 ( epi- Tephroapollin G), 3 (Acetyltephroapollin C), 4 (4''-Dehydroxytephroapollin E), and 5 ( epi- Tephroapollin F) were new. Structures were identified using relevant spectroscopic tools including optical rotations and CD data. Compounds 1 , 3 , 4 and lanceolatin A ( 6 ) behaved like papaverine by inhibiting carbachol (CCh) as well as high potassium (K+ )-mediated contractions at equivalent concentrations with varied potencies whereas (-)-Tephroapollin G ( 2 ) selectively inhibited CCh-mediated contractions but was not found active against high K+ . epi -Tephroapollin F ( 5 ) and (-)-Pseudosemiglabrin ( 7 ) in contrast were significantly more potent to abolish CCh induced contraction when compared with high K+ similar to dicyclomine. Papaverine like dual phosphodiesterase enzyme Ca++ ion inhibitory activities of 1, 3, 4 and 6 were confirmed indirectly by the bolster of the isoprenaline curves against CCh to the left whereas Ca++ inhibitory effect of 1 and 3 - 7 was confirmed by the rightward deflection of Ca++ concentration-response curves (CRCs) towards right with quashing of the maximum response in same fashion like verapamil. Moreover, compounds 2, 5 and 7 at lower concentrations showed selective blockade of muscarinic receptor similar to atropine. Oral administration of the TPTE , CHCl3 and 7 to guinea pigs significantly protected against bronchospasm induced by 0.2 % histamine aerosol in vivo ., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier B.V. on behalf of King Saud University.)- Published
- 2024
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