Polyhydroquinoline (PHQ) are the unsymmetrical Hantzsch derivatives of 1,4-dihydropyridines with several biological applications. In this work, twenty-five (3–27) new Schiff’s base derivatives of polyhydroquinoline hydrazide were synthesized in excellent to good yields by a multi-component reaction. The structures of the synthesized products (1–27) were deduced with the help of spectroscopic techniques, such as 1H-, 13C -NMR, and HR-ESI-MS. The synthesized products (1–27) were tested for their antibacterial and in vitro calcium -channel-blocking (CCB) potentials using the agar-well diffusion method, and isolated rat aortic ring preparations, respectively. Among the series, sixteen compounds were found to inhibit the growth of Escherichia coli and Enterococcus faecalis. Among them, compound 17 was observed to be the most potent one at a dose 2 µg/mL, with an 18 mm zone of inhibition against both bacteria when it was compared with the standard drug amoxicillin. Eight compounds showed CCB activity of variable potency; in particular, compound 27 was more potent, with an EC50 value of 0.7 (0.3–1.1) µg/mL, indicating their CCB effect.

Carissa opaca Stapf ex Haines (C. opaca) fruit is used traditionally in the treatment of respiratory illnesses including asthma. However, there is no scientific evidence supporting its antiasthmatic activity. The current study was conducted to evaluate its antiasthmatic effects using in vivo and in vitro approaches. The methanolic crude extract of C. opaca fruit (Co.Cr.) was used and in vivo antiasthmatic activity was carried out using ovalbumin- (OVA-) sensitized and OVA-challenged BALB/c mice. In in vitro bronchorelaxant activity of crude extract, aqueous and n-hexane fractions of C. opaca were carried out on isolated rat tracheal strips. Co.Cr. (200 and 400 mg/kg) attenuated ovalbumin-induced changes in lung histochemistry with % decrease in peribronchial inflammation of 14.1 ± 0.21 and 65.8 ± 0.22 and % decrease in total inflammatory cell count of 35.7 ± 2.80 and 53.3 ± 2.30 in bronchoalveolar lavage fluid. Co.Cr., aqueous, and n-hexane fraction of C. opaca attenuated the precontractions induced by high K+ (80 mM) and carbachol (1 μM), respectively. In conclusion, the results showed that C. opaca possesses antiasthmatic activity via relaxant effect on bronchial smooth muscle which is mediated through calcium channel blockade and antimuscarinic activity. This study provides scientific evidence of the traditional use of C. opaca in the management of allergic asthma.

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