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Trial registered on ANZCTR

Registration number

ACTRN12620000629932p

Ethics application status

Submitted, not yet approved

Date submitted

8/04/2020

Date registered

29/05/2020

Date last updated

29/05/2020

Date data sharing statement initially provided

29/05/2020

Type of registration

Prospectively registered

Titles & IDs

Public title

BOKA-T: Bioavailability Of Kawakawa Tea metabolites in human volunteers

Scientific title

BOKA-T: Bioavailability Of Kawakawa Tea metabolites in healthy male volunteers

Secondary ID [1]

None

Universal Trial Number (UTN)

U1111-1248-8566

Trial acronym

BOKA-T

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Metabolic disorders

Condition category

Condition code

Metabolic and Endocrine

Other metabolic disorders

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

This study will examine the response after an acute (single) ingestion of either water or different doses of Kawakawa tea (1g or 4g per 250ml of hot water). The postprandial state lasts for approximately 4-5 h post-meal period, the study is to be carried out for 6h. Participants under the supervision of clinical coordinator will complete a screening assessment and if eligible for entry into the trial will be required in fasted condition to consume either a kawakawa tea infusion (1g or 4g per 250ml of hot water) or only hot water within 15 minutes. Following the tea ingestion, a standard breakfast will be provided at 60 minutes. Blood will be sampled at 0, 30, 45, 60, 90, 120, 180, 240, 300 mins, and 24 h from an arm vein (total 220ml blood) by a certified phlebotomist or registered nurse. Urine samples will be collected for 24 h with a time frame of 0, 0-2, 2-4, 4-5, 5-24 h after the consumption of tea. A washout period of 1 week is required between each intervention, therefore the participants will be informed to come for their second and third intervention visits after a washout of 1 week.

Intervention code [1]

Prevention

Comparator / control treatment

Hot water (250mL)

Control group

Placebo

Outcomes

Primary outcome [1]

Composite primary outcome: To examine the bioavailability of Kawakawa and its metabolites following the consumption of tea infused with Kawakawa leaves

Timepoint [1]

Fasting blood and urine samples will be collected.
After intervention- Blood samples will be collected at 30, 45, 60, 90, 120, 180, 240, 300 mins, and at 24 hours. Urine samples will be collected for 24 hours with a time frame of 0-2, 2-4, 4-5, 5-24 hours.
Untargeted Metabolomics will be utilised to analyse these samples

Secondary outcome [1]

To measure kawakawa metabolites in plasma following consumption of different doses of Kawakawa infused Tea or hot water

Timepoint [1]

Blood samples collected at fasting and then after the intervention at 30, 45, 60, 90, 120, 180, 240, 300 mins, and at 24 hours will be analysed for Kawakawa metabolites using both targeted as well as untargeted metabolic profiling approach.

Secondary outcome [2]

To measure kawakawa metabolites in Urine collected for 24 hours after consumption of different doses of Kawakawa infused Tea or hot water.

Timepoint [2]

Urine samples collected for 24 hours with a time frame of 0, 0-2, 2-4, 4-5, 5-24 hours will be analysed for Kawakawa metabolites using both targeted as well as untargeted metabolic profiling approach.

Secondary outcome [3]

To measure the impact of Kawakawa tea ingestion on biochemical parameters of blood glucose level.

Timepoint [3]

Plasma glucose will be measured using a Roche Cobas c311 autoanalyser by enzymatic colorimetric assay. Blood samples collected at 0, 30, 45, 60, 90, 120, 180, 240, 300 mins, and at 24 hours

Secondary outcome [4]

To measure the impact of Kawakawa tea ingestion on biochemical parameters of blood insulin level.

Timepoint [4]

Plasma insulin will be measured on a Roche Cobas e411 by electro-chemiluminescence immunoassay. Blood samples collected at 0, 30, 45, 60, 90, 120, 180, 240, 300 mins, and at 24 hours

Secondary outcome [5]

To measure the impact of Kawakawa tea ingestion on biochemical parameters of blood lipids.

Timepoint [5]

Fasting plasma lipids will be analysed by Roche Cobas c311 autoanalyser by enzymatic colorimetric assay. Blood samples collected at 0, 30, 45, 60, 90, 120, 180, 240, 300 mins, and at 24 hours

Eligibility

Key inclusion criteria

Males participants will be included to participate if
• BMI- 18-30 kg/m2
• Non-smokers
• Self-reported not consuming dietary supplements
• No medical conditions

Minimum age

18 Years

Maximum age

60 Years

Sex

Males

Can healthy volunteers participate?

Yes

Key exclusion criteria

Participants will be excluded from participation if they:
• Female subjects
• Are taking dietary supplements or herbal remedies which may affect the study outcome
• Are allergic to pepper, nutmeg or similar spices
• Are diagnosed with gastrointestinal disease (i.e. celiac, Crohn’s, colitis, etc.) or pre-existing metabolic disease
• Are currently taking medications expected to interfere with normal digestive or metabolic processes including proton pump inhibitors, laxatives, etc.
• Have used antibiotics within the previous one month or were on long-term antibiotic therapy.

Study design

Purpose of the study

Prevention

Allocation to intervention

Randomised controlled trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

Participants will be randomised to receive the intervention or the control as the first in a crossover sequence using computer-generated sequences.

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Allocation sequence will be set up as through a web-based secure database. Sequences will not be accessible to the research team prior to allocation.

Masking / blinding

Open (masking not used)

Who is / are masked / blinded?

Intervention assignment

Crossover

Other design features

Randomised, Open-label, Three-arm, Three-period crossover trial

Phase

Not Applicable

Type of endpoint/s

Bio-availability

Statistical methods / analysis

Differences in the primary endpoints will be compared between treatment groups using Repeated measure ANOVA or non-parametric tests where appropriate and followed-up with posthoc tests. The relationship between secondary end-points will be assessed using multiple regression analysis.

Recruitment

Recruitment status

Not yet recruiting

Date of first participant enrolment

Anticipated

1/06/2020

Actual

Date of last participant enrolment

Anticipated

30/07/2020

Actual

Date of last data collection

Anticipated

30/09/2020

Actual

Sample size

Target

Accrual to date

Final

Recruitment outside Australia

Country [1]

New Zealand

State/province [1]

Auckland

Funding & Sponsors

Funding source category [1]

University

Name [1]

Liggins Institute, The University of Auckland

Address [1]

85 Park road, Grafton, Auckland 1023.

Country [1]

New Zealand

Primary sponsor type

University

Name

Liggins Institute, The University of Auckland

Address

85 Park road, Grafton, Auckland 1023.

Country

New Zealand

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Submitted, not yet approved

Ethics committee name [1]

Health and Disability Ethics Committees

Ethics committee address [1]

Ministry of Health
Health and Disability Ethics Committees
133 Molesworth Street, Thorndon
Wellington 6011

Ethics committee country [1]

New Zealand

Date submitted for ethics approval [1]

16/03/2020

Approval date [1]

Ethics approval number [1]

Summary

Brief summary

Kawakawa is a versatile herb, endemic to New Zealand, where it is widely used for food, medicinal, and traditional ceremonial purposes by Maori. Kawakawa leaves and fruits are reported to possess medicinal properties and are utilised for a wide range of health conditions not only limited to skin diseases but for the treatment of genitourinary,
gastrointestinal as well as respiratory diseases. A previous study by Butts et al (2019) described that there is a significant number of chemical constituents present in kawakawa leaves with potential pharmacological properties. Therefore, as a candidate for potential functional food applications, examining the bioavailability of kawakawa metabolites for human consumption is required. In-vitro or mechanistic studies carried out with kawakawa leaves and fruits have discovered that they are safe for human consumption and have potential health benefits. With the advent of this, there exists a scientific need to explore the mechanisms of human metabolism and bioavailability upon the ingestion of kawakawa tea. Therefore, the aim of this study is to evaluate the bioavailability of kawakawa metabolites from commercially available kawakawa tea leaves and its effects on other metabolic and biochemical parameters in healthy adults.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Prof Richard Mithen

Address

Liggins Institute
University of Auckland
85 Park Road
Grafton
Auckland 1023

Country

New Zealand

Phone

+64 27 201 7675

Fax

[email protected]

Contact person for public queries

Name

Richard Mithen

Address

Liggins Institute
University of Auckland
85 Park Road
Grafton
Auckland 1023

Country

New Zealand

Phone

+64 27 201 7675

Fax

[email protected]

Contact person for scientific queries

Name

Farha Ramzan

Address

Liggins Institute
University of Auckland
85 Park Road
Grafton
Auckland 1023

Country

New Zealand

Phone

+64 22 4505345

Fax

[email protected]

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

Yes

What data in particular will be shared?

All of the Individual participant data (including data dictionaries) collected during the trial will be available after de-identification, along with the study protocol.

When will data be available (start and end dates)?

Data will be available beginning 3 months following the first publication of study results and ending 36 months following publication.

Available to whom?

Data will be available to investigators who provide a methodologically sound proposal approved by the Study Steering Committee, for use to achieve the aims in the approved proposal. Proposals should be directed to the principal investigator. To gain access, requests will need to sign a data access agreement.

Available for what types of analyses?

For use to achieve the aims in an approved proposal.

How or where can data be obtained?

Proposals should be directed to the principal investigator ([email protected]). To gain access, requests will need to sign a data access agreement.

What supporting documents are/will be available?

Doc. No.	Type	Citation	Link	Email	Other Details	Attachment
7564	Study protocol			[email protected]
7565	Informed consent form			[email protected]		379568-(Uploaded-07-04-2020-14-47-46)-Study-related document.doc

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	Acute Effects of Kawakawa (Piper excelsum) Intake on Postprandial Glycemic and Insulinaemic Response in a Healthy Population.	2022	https://dx.doi.org/10.3390/nu14081638

N.B. These documents automatically identified may not have been verified by the study sponsor.

Trial Review

Documents added manually

Documents added automatically