CompletedPhase 1ACTRN12621000097842

The New Zealand Indigo naturalis dose-escalation study (NZ-INDES): a study to investigate its effect on immune responses in healthy volunteers

Impact of a single intake of Indigo naturalis on the activity of blood aryl hydrocarbon receptor in healthy individuals

Sponsor

Malaghan Institute of Medical Research

Enrollment

25 participants

Start Date

Feb 26, 2021

Study Type

Interventional

Conditions

Inflammation

Summary

This is a single dose open-label dose-escalation pilot study. Following a lead-in period for screening, recruitment, participants will be allocated to a zero-dose control group or different Indigo naturalis dose groups. The study involves a single 24 h intervention period over two study visits. Participants will be self-reported healthy adults (male or female, 18 – 65 years old), which represent the adult general population residing in Wellington, New Zealand. Following informed consent, the first five participants will take capsules containing 2 g of microcrystalline cellulose (zero-dose control group). The next group of five participants will take the lowest dose of Indigo naturalis. If data analysis of the lowest dose shows no detrimental effect on liver function, the next group of 5 individuals will take the next dose (0.5 g) of the herbal medicine and so on. If we find a consistent, significant change in blood AhR activity in plasma and/or PBMCs in this pilot study, we intent to subsequently conduct a follow up study involving administering Indigo naturalis in people with inflammatory conditions, such those associated with obesity, metabolic syndrome, diabetes or liver steatosis.

Eligibility

Sex: Both males and femalesMin Age: 18 YearssMax Age: 65 Yearss

Inclusion Criteria4

a. Anybody residing in Wellington (New Zealand), self-reported as healthy
b. Age between 18 to 65 years old
c. Participants must be willing to not consume any alcohol; use tobacco, e-cigarettes, or recreational drugs for at least 3 days prior to the study, and during the study visit days.
d. Not take any dietary supplement (e.g. vitamins, fortified drinks) and herbal medicines for at least 3 days prior to the study, and during the study visit days.

Exclusion Criteria15

a. Any known recent or current communicable diseases (e.g. HIV, hepatitis, etc.)
b. BMI < 18 kg/m2 or BMI > 35 kg/m2
c. Autoimmune diseases including rheumatoid arthritis, systemic lupus erythematosus (SLE), inflammatory bowel disease (IBD), celiac disease, pancreatitis or other malabsorption condition.
d. Chronic obstructive pulmonary disease (COPD) or other chronic respiratory conditions (including sleep apnoea)
e. Cardiovascular disease (CVD) current angina; myocardial infarction or stroke within the past 6 months; heart failure; symptomatic peripheral vascular disease; SBP > 160 mmHg and/or DBP > 100 mmHg (with or without hypertensive medication)
f. Type 1 or type 2 diabetes mellitus
g. Chronic renal impairment; liver disease e.g. cirrhosis; prior bariatric surgery, neurological, psychiatric, or musculoskeletal disease (e.g. rheumatoid arthritis); history of abnormal liver function
h. History of malignancy within the last 5 years, with the exception of basal cell carcinoma that has been completely excised prior to study entry remain eligible;
i. Recent prior (previous 4 weeks) or current use of antibiotics
j. Recent prior (previous 4 weeks) or current respiratory infection
k. Current or prior eating disorder (e.g. anorexia nervosa, bulimia)
l. Food allergy or intolerance, including gluten, soy, dairy, nuts & seed intolerance
m. Pregnant or breastfeeding; or intent to become pregnant during study duration
n. Current participation in another clinical intervention study
o. Inability to provide written informed consent

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Interventions

Study design: This is a single dose, open-label, dose-escalation pilot study. Following a lead-in period for screening, recruitment, participants will be allocated either to a zero-dose control grou

Study design: This is a single dose, open-label, dose-escalation pilot study. Following a lead-in period for screening, recruitment, participants will be allocated either to a zero-dose control group, or, only one of the four different (Dose 1 - 4 ) Indigo naturalis dose groups stated below. The study involves a single 24 h intervention period over two study visits. Intervention items: Control intervention item: zero-dose control (capsules containing 2 g of microcrystalline cellulose) Dose 1: 0.25 g Indigo naturalis (capsules containing 0.25 g Indigo naturalis powder) Dose 2: 0.5 g Indigo naturalis (capsules containing 0.5 g Indigo naturalis powder) Dose 3: 1 g Indigo naturalis (capsules containing 1 g Indigo naturalis powder) Dose 4: 2 g Indigo naturalis (capsules containing 2 g Indigo naturalis powder) Mode of administration: Oral (capsule form) Strategy used to monitor adherence: Capsules containing either 2 g microcrystalline cellulose (zero-dose control) or a particular dose (0.25 g, 0.5 g, 1 g, or 2 g) of Indigo naturalis, will be administered to a particular participant under the direct supervision of a clinical research nurse. Hence, adherence to the intervention is directly monitored, confirmed and recorded on site. Method of allocation: This study is a non-randomised study where participants will be allocated to either the zero-dose control (2 g of microcrystalline cellulose), or a specific dose of Indigo naturalis (0.25 g, 0.5 g, 1 g, or 2 g), in the order in which they are enrolled into the study. Once five participants have been recruited to receive a particular intervention, the next five participants will be allocated to the next subsequent dose of Indigo naturalis.