Oral curcumin for Alzheimer's disease: Tolerability and efficacy in a 24-week randomized, double blind, placebo-controlled study

Alzheimer's Research and Therapy (Impact Factor: 3.98). 10/2012; 4(5):43. DOI: 10.1186/alzrt146
Source: PubMed


Curcumin is a polyphenolic compound derived from the plant Curcuma Long Lin that has been demonstrated to have antioxidant and anti-inflammatory effects as well as effects on reducing beta-amyloid aggregation. It reduces pathology in transgenic models of Alzheimer's disease (AD) and is a promising candidate for treating human AD. The purpose of the current study is to generate tolerability and preliminary clinical and biomarker efficacy data on curcumin in persons with AD.
We performed a 24-week randomized, double blind, placebo-controlled study of Curcumin C3 Complex® with an open-label extension to 48 weeks. Thirty-six persons with mild-to-moderate AD were randomized to receive placebo, 2 grams/day, or 4 grams/day of oral curcumin for 24 weeks. For weeks 24 through 48, subjects that were receiving curcumin continued with the same dose, while subjects previously receiving placebo were randomized in a 1:1 ratio to 2 grams/day or 4 grams/day. The primary outcome measures were incidence of adverse events, changes in clinical laboratory tests and the Alzheimer's Disease Assessment Scale - Cognitive Subscale (ADAS-Cog) at 24 weeks in those completing the study. Secondary outcome measures included the Neuropsychiatric Inventory (NPI), the Alzheimer's Disease Cooperative Study - Activities of Daily Living (ADCS-ADL) scale, levels of Aβ1-40 and Aβ1-42 in plasma and levels of Aβ1-42, t-tau, p-tau181 and F2-isoprostanes in cerebrospinal fluid. Plasma levels of curcumin and its metabolites up to four hours after drug administration were also measured.
Mean age of completers (n = 30) was 73.5 years and mean Mini-Mental Status Examination (MMSE) score was 22.5. One subject withdrew in the placebo (8%, worsened memory) and 5/24 subjects withdrew in the curcumin group (21%, 3 due to gastrointestinal symptoms). Curcumin C3 Complex® was associated with lowered hematocrit and increased glucose levels that were clinically insignificant. There were no differences between treatment groups in clinical or biomarker efficacy measures. The levels of native curcumin measured in plasma were low (7.32 ng/mL).
Curcumin was generally well-tolerated although three subjects on curcumin withdrew due to gastrointestinal symptoms. We were unable to demonstrate clinical or biochemical evidence of efficacy of Curcumin C3 Complex® in AD in this 24-week placebo-controlled trial although preliminary data suggest limited bioavailability of this compound.
Trial registration
ClinicalTrials.gov Identifier: NCT00099710.

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Available from: Karen Gylys, Nov 19, 2014
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    • "months patients with mild-to-moderate AD improvements in cognition Rogers et al. 1993 Diclofenac + Misoprostol N/A 25 weeks patients with mild-to-moderate AD no changes in cognition Scharf et al. 1999 Prednisone 20 then 10mg/d 4 weeks then 1 year patients with AD no beneficial changes in cognitive tests Aisen et al. 2000 Hydrochloroquine 200 or 400mg/d 18 months patients with early AD no cognitive/behavioural improvements van Gool et al. 2001 Nimesilude 100mg twice daily 24 weeks patients with probable AD no effect on cognition, clinical status or behaviour Aisen et al. 2002 Rofecoxib 25mg/d 12 months patients with mild-to-moderate AD no delay in cognitive decline Aisen et al. 2003 Naproxen 220mg twice daily 12 months patients with mild-to-moderate AD no delay in cognitive decline Aisen et al. 2003 Rofecoxib 25mg/d 12 months patients with mild-to-moderate AD no improvements in cognition and behaviour Reines et al. 2004 Rofecoxib 25mg/d up to 4 years patients with MCI no improvements in cognition Thal et al. 2005 Celecoxib 200mg twice daily up to 7 years people 70 years or older with family history of AD no improvements in cognitive functions Martin et al. 2008 Naproxen 220mg twice daily up to 7 years people 70 years or older with family history of AD no improvements in cognitive functions Martin et al. 2008 Corticosteroids Estradiol 2mg/d 6 weeks women with senile dementia AD type improvements in cognition and mood in 3/7 women Fillit et al. 1986 Estrogen 1.25mg/d 16 weeks women with mild-to-moderate AD no improvements in cognition or mood Henderson et al. 2000 Curcumin Curcumin 1 or 4g/d 6 months patients with probable AD probable slower decline in cognition Baum et al. 2008 Curcumin C3 Complex 2 or 4g/d 24 weeks patients with mild-to-moderate AD no difference in clinical or biomarker efficacy measures Ringman et al. 2012 Ginkgo biloba EGb 761 240mg/d 24 weeks outpatients with presenile and senile AD better cognition and activities of daily living Kanowski et al. 1997 EGb 761 240mg/d 3 months patients wit mild-to-moderate AD better attention and memory Maurer et al. 1997 EGb 761 120mg/d 52 weeks outpatients with mild to severe AD better cognition and daily living Le Bars et al. 1997 EGb 761 120 or 240mg/d 26 weeks patients with AD no convincing differences in cognition Schneider et al. 2005 "
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    • "Curcumin has been attributed with neuroprotective potential and the Indo-US Cross National Dementia Study reported that India had a lower incidence and a lower prevalence of Alzheimer's disease (AD) compared to a reference American population (Chandra et al. 1998, 2001). To date, there have been two completed clinical trials investigating the neuroprotective efficacy of curcumin with regard to AD, but both studies have not reported significant neuroprotective effects (Baum et al. 2008; Ringman et al. 2012). One possible explanation for the lack of neuroprotective efficacy may be the low bioavailability of curcumin. "
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