Inhibition of porcine detrusor contractility by the flavonoid fraction of Bryophyllum pinnatum – a potential phytotherapeutic drug for the treatment of the overactive bladder syndrome

Aims: To determine if the phytotherapeutic agent, Bryophyllum pinnatum, could serve as an alternative drug for the overactive bladder syndrome, and to characterise the fraction responsible for the inhibition of detrusor contractility. Methods: Fractions were prepared from the MeOH extract of B. pinnatum and further analysed by HPLC-PDA-MS. Detrusor muscle strips were prepared from porcine bladders and the electrically induced muscle contractility measured by organ bath. The effect of B. pinnatum leaf press juice (2.5–10%), a flavonoid fraction (0.1–1 mg/ml), and a bufadienolide fraction (0.1–40 μg/ml) on detrusor contractility was assessed and compared with controls (polar fraction (0.5–5 mg/ml) and oxybutynin (10−8–10−6 M)). Results: The press juice, at a concentration of 10% led to a reduction of detrusor contractility. Bladder strips treated with the flavonoid fraction showed a significant reduction of the contractility to 21.3 ± 5.2% (1 mg/ml) while the bufadienolide fraction had no inhibitory effect in the investigated concentrations. The polar fraction showed a reduction of the contractility in a pH-dependent fashion. At 10−6 M concentration oxybutynin reduced the detrusor contractility to 21.9 ± 4.7%. Conclusions: The flavonoid fraction of Bryophyllum pinnatum reduces the porcine detrusor contractility in a dose- and time-dependent manner. Fractions from B. pinnatum may be a new pharmacological approach for the treatment of OAB.