• Time of maximum concentration (tmax) [ Time Frame: A 12-hour post-administration period (15, 30, 45, 60, 90, 120, 180, 240, 360, 480, 600, and 720 minutes). ]
  The time of maximum concentration (tmax) of the known bioactive compounds and their metabolites will be calculated from the concentrations measured by high performance liquid chromatography tandem mass spectrometry in order to help determine dosage intervals
• Half-life (t1/2) [ Time Frame: A 12-hour post-administration period (15, 30, 45, 60, 90, 120, 180, 240, 360, 480, 600, and 720 minutes). ]
  The half-life (t1/2) of the known bioactive compounds and their metabolites will be calculated from the plasma concentrations measured by high performance liquid chromatography tandem mass spectrometry to help determine dosage intervals.
• Temporal changes in antioxidant status [ Time Frame: A 12-hour post-administration period (15, 30, 45, 60, 90, 120, 180, 240, 360, 480, 600, and 720 minutes). ]
  Ferric reducing ability of plasma (FRAP) will be measured in the plasma collected at each time point to generate a graph of antioxidant potential over time.
• Urinary clearance [ Time Frame: Over 12 hours post-administration ]
  The concentration of bioactive compounds from Centella asiatica (triterpenes, caffeoylquinic acids, and their metabolites) will be measured in a pooled urine sample collected over 12 hours after CAP administration and analyzed using high performance liquid chromatography tandem mass spectrometry.
• Oral temperature [ Time Frame: 0, 360 and 720 minutes after administration ]
  Oral temperature will be measured in degrees Celsius by means of a thermometer. Temperatures falling outside the normal range (33.2-38.2 degrees Celsius) will be compared to baseline levels, and alternative clinical explanations considered, in order to determine if they are attributable to the study intervention.
• Pulse rate [ Time Frame: 0, 360 and 720 minutes after administration ]
  Pulse rate will be measured peripherally over one minute. Pulse rates falling outside the normal range (60-80 beats per minute) will be compared to baseline levels, and alternative clinical explanations considered, in order to determine if they are attributable to the study intervention.
• Seated blood pressure [ Time Frame: 0, 360 and 720 minutes after administration ]
  Seated blood pressure (systolic and diastolic) will be measured in millimeters mercury. Blood pressure readings falling outside the normal range (90-130/60-80 millimeters Mercury) will be compared to baseline levels, and alternative clinical explanations considered, in order to determine if they are attributable to the study intervention.
• Body mass index [ Time Frame: 0, 360 and 720 minutes after administration ]
  Height in centimeters and weight in kilograms will be measured and aggregated to measure body mass index in kilograms per meter squared (kg/m2). Changes in body mass index greater than two kilograms per meter squared from baseline levels, along with consideration of alternative clinical explanations, will be used to determine attribution to the study intervention.
• Electrocardiography [ Time Frame: 0, 360 and 720 minutes after administration ]
  Resting electrocardiography will be measured for up to five minutes using a five lead mobile electrocardiogram. PR interval length, QRS complex duration, and the QT interval will be measured in milliseconds. Each parameter will be compared to the value obtained at baseline (time 0, prior to intervention administration). For any differences seen from the baseline value, alternative clinical explanations will be considered in order to determine if the change is attributable to the study intervention.
• Liver function [ Time Frame: 0, 360 and 720 minutes after administration ]
  A comprehensive metabolic panel will measure alanine aminotransferase and aspartate aminotransferase in units per liter as markers of liver function. Enzyme levels falling outside the normal range (0-35 Units per liter for alanine aminotransferase and 17-59 Units per liter for aspartate aminotransferase) will be compared to baseline levels, and alternative clinical explanations considered, in order to determine if elevations are attributable to the study intervention. The investigators will aggregate the measures by using an elevation in either enzyme function as a reflection of overall liver function.
• Kidney function [ Time Frame: 0, 360 and 720 minutes after administration ]
  A comprehensive metabolic panel will measure creatinine and blood urea nitrogen levels in milligrams per deciliter as markers of kidney function. Each parameter falling outside the normal range ( 0.5 to 1.2 milligrams per deciliter for creatinine and 7 to 20 milligrams per deciliter for blood urea nitrogen), will be compared to baseline values and alternative clinical explanations considered, in order to determine if elevations are attributable to the study intervention. The investigators will aggregate the measures by using an elevation in either blood urea nitrogen or creatinine as a reflection of overall kidney function.
• Adverse events [ Time Frame: 0, 6, 12 and 24 hours after administration. ]
  A standard multi-system questionnaire will record the type and severity (range 0 = none, 1 = mild, 2 = moderate, 3 = severe, 4 = life-threatening, 5 = fatal) of any adverse events. The investigators will evaluate any changes in symptoms from baseline, and consider alternative clinical explanations, to determine if the changes are adverse events attributable to the study intervention.

PRIMARY OBJECTIVES:

1. To assess the bioavailability and rate of clearance of Centella asiatica derived compounds in mildly demented elders on cholinesterase inhibitor therapy through a pharmacokinetic study.
2. To determine the acute tolerability of a Centella asiatica product in mildly demented elders on cholinesterase inhibitor therapy.

OUTLINE:

Participants will orally consume a single administration of a standardized Centella asiatica water extract product (CAP). Two doses (2g and 4g CAW) will be administered on separate occasions, at least two weeks apart. The levels of known bioactive compounds present in Centella asiatica will be measured in human plasma and urine over 12 hours after administration of each of the doses.

• Cognitive Impairment
• Elderly

• Drug: 2g Centella asiatica water extract product
  2g of Centella asiatica water extract (CAW) in a standardized product containing excipients to improve palatability, color matching and dispersability. The product (CAP) is a powder which will be dissolved in 10-12 ounce of water and consumed by mouth once on an empty stomach.
  Other Name: CAP 2g
• Drug: 4g Centella asiatica water extract product
  4g of Centella asiatica water extract (CAW) in a standardized product containing excipients to improve palatability, color matching and dispersability. The product (CAP) is a powder which will be dissolved in 10-12 ounce of water and consumed by mouth once on an empty stomach.
  Other Name: CAP 4g

• Experimental: 2g CAP
  Single administration of 2g of Centella asiatica water extract standardized product dissolved in 10-12 ounce of water and consumed by mouth once on an empty stomach.
  Intervention: Drug: 2g Centella asiatica water extract product
• Experimental: 4g CAP
  Single administration of 4g of Centella asiatica water extract standardized product dissolved in 10-12 ounce of water and consumed by mouth once on an empty stomach.
  Intervention: Drug: 4g Centella asiatica water extract product

Inclusion Criteria:

1. Age 65-85, male and female
2. Meet the National Institute of Aging - Alzheimer's Association core clinical criteria for mild cognitive impairment or probable Alzheimer's disease dementia with a Clinical Dementia Rating (CDR) score of 0.5-1 and MMSE score of 20-28
3. Report a history of subjective memory decline with gradual onset and slow progression over the last one year before screening; MUST be corroborated by an informant
4. On cholinesterase inhibitor therapy for Alzheimer's disease (AD) and must be on a stable dose for at least 12 weeks prior to baseline
5. Caregiver/study partner that can accompany participant to all study visits
6. Sufficient English language skills to complete all tests
7. Sufficient vision and hearing to complete all tests
8. No known allergies to Centella asiatica or CAP excipients
9. Willingness to discontinue all botanical dietary supplements for one week prior to and during each study visit
10. Willingness to comply with a 48-hour low plant diet for each study visit
11. Absence of significant depression symptoms (Geriatric Depression Scale-15 score of <12)
12. Body Mass Index (BMI) greater than 17 and less than 35 at screening
13. General health status that will not interfere with the ability to complete the study

Exclusion Criteria:

1. Current smoking, alcohol or substance abuse according to DSM-V criteria
2. Women who are pregnant, planning to become pregnant or breastfeeding
3. Men who are actively trying to conceive a child or planning to within three months of study completion
4. Severe aversion to venipuncture
5. Abnormal laboratory evaluation indicating asymptomatic and untreated urinary tract infection
6. Cancer within the last five years, with the exception of localized prostate cancer (Gleason Grade <3) and non-metastatic skin cancers
7. Comorbid conditions such as diabetes mellitus, kidney failure, liver failure, hepatitis, blood disorders, clinical symptomatic orthostatic hypotension, and unstable or significantly symptomatic cardiovascular disease
8. Significant disease of the central nervous system such as brain tumor, seizure disorder, subdural hematoma, cranial arteritis, or clinically significant stroke
9. Major depression, schizophrenia, or other major psychiatric disorder defined by DSM-V criteria
10. Medications: sedatives (except those used occasionally for sleep), central nervous system active medications that have not been stable for two months (including beta blockers, cimetidine, SSRIs, SNRIs), anticoagulants (i.e. Warfarin), investigational drugs used within five half-lives of baseline visit, systemic corticosteroids, neuroleptics, anti-Parkinsonian agents, narcotic analgesics, nicotine (tobacco, patches, gum, lozenges, etc.), Cannabis sativa (herb or edibles)
11. Non-Alzheimer dementia such as vascular dementia, normal pressure hydrocephalus or Parkinson's disease
12. Mini Mental State Examination (MMSE) score of <20 or >28 or CDR score >1 or zero
13. Unwilling to maintain stable dosage of AD medications throughout study duration
14. Inability or unwillingness of individual or legal guardian/representative to give written informed consent.
15. Current drug or alcohol use or dependence that, in the opinion of the site investigator, would interfere with adherence to study requirements.