主催: The Japanese Pharmacological Society, The Japanese Society of Clinical Pharmacology
会議名: WCP2018 (18th World Congress of Basic and Clinical Pharmacology)
開催地: Kyoto
開催日: 2018/07/01 - 2018/07/06
Background. Jungle ginger has been traditionally used by Sarawak natives as medicine to treat urological disorders. Drugs that relax prostatic smooth muscle are used to manage urinary symptoms associated with benign prostatic hyperplasia.
Aims. To assess the pharmacological effects of the jungle ginger on prostate contractility and to isolate its bioactive components.
Methods. This is original work reporting the biological effects of jungle ginger on isolated rat prostate contractility. Jungle ginger rhizome, root, leaf and stem were harvested from Sarawak and extracted using water. Activity of these extracts was evaluated pharmacologically by assessing their effects on contractions of isolated rat prostate maintained in a modified Krebs solution at 37°C and bubbled with carbogen gas. Nerve-mediated contractions were evoked electrically (EFS) (0.1-20 Hz, 0.5 ms pulse duration, 60 V) while direct muscle stimulation was achieved by application of the exogenously administered agonists. Pharmacological tools were used to identify mechanisms of action. Chemical isolation and identification were performed using derivatization, HPLC, LCMS and 1H NMR.
Results. Jungle ginger rhizome (p=0.0004, n=6), root (p<0.0001, n=6) and stem (p=0.0057, n=6) extract at 2.0 mg/mL inhibited EFS-induced contractions of rat prostatic smooth muscle, while leaf extract did not exhibit bioactivity (p=0.0988, n=6). Contractions mediated by exogenous administration of noradrenaline (1 nM-100 μM, n=6), acetylcholine (1 nM-100 μM, n=6), ATP (300 nM-1 mM, n=6), or tyramine (10 nM-100 μM, n=4) were not inhibited by rhizome extract. EFS-induced contractions were still attenuated by the rhizome extract in the presence of prazosin (300 nM, n=6), suramin (30 nM, n=6), yohimbine (1 μM, n=6), idazoxan (1 μM, n=6), propranolol (1 μM, n=6), atropine (1 μM, n=6), methysergide (1 μM, n=6), mepyramine (1 μM, n=6), hexamethonium (10 μM, n=6), desipramine (100 nM, n=6), 8-phenyltheophylline (10 μM, n=6), and AH6809 (10 μM, n=6). Aqueous fraction of the extract was active and 1H NMR signal revealed the presence of carbohydrates.
Conclusions. Jungle ginger rhizome extract inhibits contractility of rat prostatic smooth muscle by an indirect prejunctional mechanism that inhibits exocytotic release of neurotransmitter. Bioactive component(s) able to attenuate nerve-mediated contractions is/are only present in the highly polar liquid phase of the extract.
