Presence of antispasmodic, antidiarrheal, antisecretory, calcium antagonist and acetylcholinesterase inhibitory steroidal alkaloids in Sarcococca saligna

The aim of this investigation was to see if the crude extract of Sarcococca saligna (Ss.Cr) contains chemicals with gut function inhibitory activity by using in vitro and in vivo assays. Ss.Cr caused a dose-dependent (0.03 - 3 mg/mL) inhibitory effect on K+-induced contractions in rat stomach fundus, guinea-pig ileum and rabbit jejunum preparations. The calcium channel blocking (CCB) activity was confirmed when Ss.Cr caused a rightward shift in the Ca++ dose-response curves. It also potentiated, at lower doses (0.001 - 0.03 mg/mL), the contractile effect of a fixed dose of acetylcholine (ACh), similar to physostigmine, and suppressed the effect of ACh at higher doses (0.3 - 1.0 mg/mL). Both Ss.Cr and physostigmine inhibited acetylcholinesterase (AChE), in the in vitro assay, confirming the AChE inhibitory activity. In the in vivo studies, Ss.Cr exhibited antidiarrheal and antisecretory activities against castor oil-induced diarrhea and intestinal fluid accumulation in mice. Characteristic steroidal compounds of the plant (saracocine, saracodine, saracorine and alkaloid-C), exhibited a similar combination of AChE inhibitory and CCB activities. Thus this study provides a sound mechanistic base for some of the traditional uses of the plant in hyperactive gut states, in addition to providing the first evidence for verapamil to possess additional AChE inhibitory activity. Furthermore, these characteristic compounds with dual activity may be good candidates for further studies on their usefulness in Alzheimer's disease.