METHODS: MEDLINE, EMBASE, PsycINFO, CENTRAL and clinicaltrials.gov were searched up to 7 February 2017. Two independent reviewers selected randomized controlled trials (RCTs) of treatments to alleviate agitation in people with all-types dementia. Data were extracted using standardized forms and study quality was assessed using the revised Cochrane Risk of Bias Tool for RCTs. Data were pooled using meta-analysis. The primary outcome, efficacy, was 8-week response rates defined as a 50% reduction in baseline agitation score. The secondary outcome was treatment acceptability defined as treatment continuation for 8 weeks.

RESULTS: Thirty-six RCTs comprising 5585 participants (30.9% male; mean ± standard deviation age, 81.8 ± 4.9 years) were included. Dextromethorphan/quinidine [odds ratio (OR) 3.04; 95% confidence interval (CI), 1.63-5.66], risperidone (OR 1.96; 95% CI, 1.49-2.59) and selective serotonin reuptake inhibitors as a class (OR 1.61; 95% CI, 1.02-2.53) were found to be significantly more efficacious than placebo. Haloperidol appeared less efficacious than nearly all comparators. Most treatments had noninferior treatment continuation compared to placebo, except oxcarbazepine, which was inferior. Findings were supported by subgroup and sensitivity analyses.

AIM OF THE STUDY: The present study was carried out to examine the potential modulatory effects of three commercially available active components (asiaticoside, asiatic acid and madecassic acid) and four extracts (aqueous, ethanol, dichloromethane and hexane) of CA on three major cDNA-expressed human cytochrome P450 (CYP) isoforms.

MATERIALS AND METHODS: High-performance liquid chromatography (HPLC)-based enzyme assays, namely tolbutamide 4-methyhydroxylase, dextromethorphan O-demethylase and testosterone 6beta-hydroxylase assays were developed to probe activities of CYP2C9, CYP2D6 and CYP3A4, respectively. Probe substrates were incubated with or without each active component and extract for each isoform, followed by examination of the kinetics parameters, IC(50) and K(i), to characterize modulatory effects.

RESULTS: CYP2C9 was more susceptible to inhibitory effects by CA extracts compared to CYP2D6 and CYP3A4. Moderate degree of inhibition was observed in ethanol (K(i)=39.1 microg/ml) and dichloromethane (K(i)=26.6 microg/ml) extracts implying potential risk of interaction when CYP2C9 substrates are consumed with CA products. The two extracts however showed negligible inhibition towards CYP2D6 and CYP3A4 (IC(50)'s of 123.3 microg/ml and above). Similarly CA aqueous and hexane extracts did not significantly inhibit all three isoforms investigated (IC(50)'s of 117.9 microg/ml and above). Among the active constituents investigated, asiatic acid and madecassic acid appeared to selectively inhibit CYP2C9 and CYP2D6 more than CYP3A4. Of particular interest is the potent inhibitory effect of asiatic acid on CYP2C9 (K(i)=9.1 microg/ml). This signifies potential risk of interaction when substrates for this isoform are taken together with CA products with high asiatic acid content. Inhibitions of asiatic acid with the other isoforms and that of madecassic acid with all isoforms were only moderate (K(i)'s ranged from 17.2 to 84.4 microg/ml). On the other hand, the IC(50) values for asiaticoside were high (1070.2 microg/ml or above) for all three isoforms, indicating negligible or low potential of this compound to modulate CYP enzymatic activity.