Insight into the Mechanisms Underlying the Tracheorelaxant Properties of the Sideritis raeseri Extract

Abstract

Sideritis raeseri Boiss. and Heldr. (Lamiaceae), known as “mountain tea,” is a native plant from the Mediterranean region, which is widely used in traditional medicine. This study evaluates the effects of the ethanol extract of Sideritis raeseri (SR) on airway smooth muscle activity and identifies the underlying mechanism. The S. raeseri extract (SRE) was extracted from air-dried parts of the shoot system of SR. The SRE (0.3–2 mg/mL) was tested in isolated rabbit tracheal rings, suspended in the organ bath, filled with Krebs solution, and bubbled with the carbogen mixture (95% O2/5% CO2) under a resting tension of 1 g in 37°C. In in vitro experiments, the SRE relaxed against acetylcholine-induced constriction in tracheal rings. Furthermore, SRE inhibited Ca2+-induced contractions in carbachol (CCh, 1 μM) as well as in the K+-depolarized trachea (80 mM). Our findings showed the NO/cGMP involvement in tracheorelaxant effects of SR. To this end, the effect of the SRE was potentiated by bradykinin (nitric oxide (NO) synthase activator, 100 nM), whereas it was inhibited by ODQ (inhibitor of NO-sensitive guanylyl cyclase, 10 μM) and L-NAME (NO synthase inhibitor, 100 μM), as well as indomethacin (cyclooxygenase inhibitor, 10 μM). These data suggest that the tracheorelaxant effect of the SRE is mediated at least partly by NO/cyclic guanosine monophosphate and cyclooxygenase-1-prostaglandin E2-dependent signaling. These findings indicate that the SRE may be used in various respiratory disorders.

Vasorelaxant Effects of the Vitex Agnus-Castus Extract

“…The fruits of VAC ( Vitex agnus-castus , L) were collected carefully from Albania. Plant materials were professionally determined by a botanist and then manually picked, cleaned up of adulterants, and shade-dried away from strong winds [ 17 , 22 ]. Then, it was further grinded to a coarse powder by a grinding machine.…”

“…Bradykinin was dissolved in 0.1 M acetic acid; indomethacin was dissolved in ethanol, while zaprinast was dissolved in DMSO at 10 mM. Unless otherwise specified, all the drugs were dissolved in distilled water [ 17 , 22 ]. Of note, all experimental solutions of drugs were made fresh daily.…”

Flavonoids derived from medicinal plants as a COVID‐19 treatment

“…Phytochemicals from medicinal plants are also used as potent medications against COVID-19. Therefore, more accurate molecular characterization of SARS-CoV-2 may aid in the development of COVID-19 therapeutic options such as vaccines and/or medications (Krasniqi et al, 2020). This paper examines current developments in medication and the effectiveness of natural plant-based remedies against COVID-19, especially flavonoids-derived medications.…”

“…Phytochemicals from medicinal plants are also used as potent medications against COVID‐19. Therefore, more accurate molecular characterization of SARS‐CoV‐2 may aid in the development of COVID‐19 therapeutic options such as vaccines and/or medications (Krasniqi et al, 2020).…”

The mechanisms underlying the role of Vitex agnus-castus in mastalgia

“…Many medicinal plants are commonly used in alternative medicine due to their curative roles reported in many disorders (4,5,28,29). Moreover, herbal medicinal products are widely considered to be compatible with our body conditions and have more effi cacy and likely fewer side effects compared with synthetic drugs.…”