Glycative Stress Research
Online edition : ISSN 2188-3610
Print edition : ISSN 2188-3602
Received : January 10, 2020
Accepted : May 15, 2020
Published online : June 30, 2020
doi:10.24659/gsr.7. 2_169

Original article

The effects and safety of food containing a labdane type diterpenoid (labdane)on knee joint problems of healthy adults: An uncontrolled open-label trial.
Arata Paul Yamasaki 1), Ryuhei Beppu 2), San-no-suke Asaga 1),
Chiiko Nagamatsu 2), Koichiro Komai 3)
1) Veritas Co., Ltd., Tokyo, Japan
2) Veritas Hanbai Co., Ltd., Tokyo, Japan
3) Department of Applied Biological Chemistry School of Agriculture, Kinki University, Nara, Japan

Abstract

The knee joint problem is one of the major problems for elderly people. The labdane 8 (17),12-diene-15,16-dial (hereinafterreferred to as "the Labdane"), which is contained in the Japanese white turmeric leaf and rhizome has demonstrated toinhibit degradation of hyaluronic acid. Since hyaluronic acid is important for lubricating joints, the Labdane is expected tohave a role of maintaining joint health. Here, we firstly report the clinical effect of the Labdane on knees. In an uncontrolled
single-arm open-label trial, 60 healthy subjects (ages 48 to 88 years) with a discomfort in the knee joint received 0.065 mgof the Labdane-rich LTDT (labdane-type diterpene compounds) per day for 8 weeks. The discomfort of the knee joint
was measured every 4 weeks from the start of intake until 8 weeks after beginning the test food ingestion using the visual
analog scale (VAS). The results of each VAS score were 4.7 ± 2.2 at 0 weeks, 3.4 ± 2.3 at 4 weeks and 2.6 ± 2.3 at 8 weeks.
Statistically significant differences were observed at 4 weeks (p < 0.001) and 8 weeks (p < 0.001) against the 0 weeks ofintake. No adverse effects were observed. This preliminary study provided a basic finding that taking the Labdane-rich LTDT
0.065 mg/day for 4 and/or 8 weeks in healthy adult men and women with a discomfort in the knee joint is confirmed to besignificantly effective and safe.

KEY WORDS: foods with functional claims, labdane, joint, knee, labdane-type diterpene compounds

Introduction
Japan faces the challenges of a super-aging society. Oneof these issues is known as locomotive syndrome, which isa salient feature when considering a healthy life expectancy.
Locomotive syndrome, also referred to as motor organ
syndrome, and commonly known as “ Locomo” was first
proposed by the Japanese Orthopedic Association in 2007.
It is defined as “the need for long-term care and a high riskof long-term care due to musculoskeletal disorders” 1). The
major cause of Locomo is cartilage exhaustion due to aging.
It has been observed that cartilage exhaustion occurs
most often in the knees. It is estimated that a total of 25.3
million people (42.6% male, 62.4% female) of Japanese over
the age of 40 have problems with their knee joints 2). Since
the knee joint bears a higher load than the other joints, thefrequency of occurrence of knee problems is higher than thatof other joints. As symptoms worsen, discomfort increases.
These adverse conditions affect walking and cause daily
activities to be restricted. Locomo is one of the main factorsthat result in a significant deterioration in the overall qualityof life (QOL) in elderly people 3).
The “ Overview of the 2013 National Living Basic
Survey”, listed the main cause for the need for nursing care,
as well as the amount of required care, to be “ joint problems”
with 20.7% of the population. This was followed by “ weakness
due to aging” at 15.4%, and “ fractures /falls” at 14.6% 4).
According to the “ Physical Activity Standards for Health
Promotion 2013”, ​​the ability to maintain and increase
appropriate physical activity, as appropriate to the life stage,
can reduce the risk of Locomo 5).

Corresponding to: Yamasaki AP
Ichiboshi Bldg. 4F 2-29-14 Shiba Minato-ku Tokyo 105- 0 014 Japan

TEL: + 81-3-5232-3491 FAX: +81-3 -3453-9973
e-mail: ap.yamasaki@veritasnet.jp
Co-authors: Beppu R, v.rbeppu@veritas-net.jp;
Asaga S, s.asaka@veritasnet. jp; Nagamatsu C, chknaga@ezweb.ne.jp;
Komai K, 95sy3w@bma.biglobe.ne.jp_ 169 _

Glycative Stress Research 2020; 7 ( 2) : 169-173(c) Society for Glycative Stress Research

The Effects of a Labdane Type Diterpenoid on Knee Joint Problems

These reports indicate that maintaining and improving
the health of the knee joint is a key factor when considering
the improvement of healthy life expectancy. In turn, this isconsistent with the concept of the functional labeling foodsystem. Since its launch in Japan in 2015, the new functionallabeling food system has had a reduction of knee discomfort
as one of its most important goals.
Problems with the knee joint can occur not only for theelderly but for the general public as well. Knee joint problems
can result in psychosocial factors, such as stress, as well as
physical limitations. Finally, it has been empirically observedthat problems with knee joints reduce not only personal
QOL, but also work productivity.
Curcumin is a major component of spring turmeric andautumn turmeric. However the Japanese white turmericcontains little or no curcumin. The Japanese white turmeric
does contain a labdane-type diterpene compound (LTDT),
which is an essential oil component. It contains 85 to 90%
labdane 8 (17), 12-diene-15, 16-dial as its main component(hereinafter referred to as (“the Labdane”). Labdane is foundin trace amounts in ginger, turmeric, and plants of the genus
Hana-myoga. The Japanese white turmeric contains 80-100
times the concentration of labdane in comparison with them.
Additionally, white turmeric leaf and/or rhizome extract, whichcontains these large quantities of labdane, has demonstrated
the ability (in vitro) to inhibit the enzyme that causes thedegradation of hyaluronic acid (HA). Since HA is considered
an important fluid that is known to lubricate joints, itspreservation is considered important in maintaining good
joint health6). However, there are still no reports of clinicalstudies focusing on the consumption of labdane. Although

this labdane containing food has already been sold for 4 years
from 2015 to 2019, with no reported adverse effects, noorganized studies have been done to determine its efficacy.
The purpose of this study is to examine the effects of thelabdane on discomfort in the knee joint. In this study, foodcontaining the Labdane -rich LTDT (0.065 mg/day) was
continuously taken for 8 weeks by healthy adult males andfemales. The population ranged in age from 48 to under 90
years. All had knee discomfort as accessed using the visual
analog scale (VAS).

Methods

Participants
Subjects were recruited from those who wished topurchase healthy food and had discomfort in their joints.
Among the 91 applicants, 60 healthy subjects, who met the
selection criteria shown in Fig. 1 and did not violate theexclusion criteria, were enrolled.
Written and verbal explanations were given as to the
purpose, method, and expectations of the study. The 60
enrollees, ages 48 to 88 years, all signed informed consent
forms.
During the observation period, subjects were instructed
not to make substantial changes in lifestyle habits such as
eating, exercising, smoking, and taking medicine. They werealso told not to engage in excessive exercise that greatly
deviated from their normal daily routine. Subjects were also
asked to ingest the test food per daily allotment and to avoid

Selection criteria

Exclusion criteria

Fig. 1. Flow chart of the clinical trial.

_ 170 _Glycative Stress ResearchMaterials and test food
The test food used was manufactured by AlimentIndustries Co., Ltd as a soft capsule and includes the Labdanerich LTDT 0.0325 mg/capsul as test food. Since the daily
intake was 2 capsules, the daily total intake of the Labdanerich LTDT was 0.065 mg.

Study design
The test food intake period for this study was 8 weeks,with observations was conducted every week from thestart of intake until 8 weeks after beginning the test foodingestion. The test food was administered as 2 capsules per
day with no time of day specified for consumption.
Although originally planned as a randomized, doubleblind, parallel-group comparison study, the trial design waschanged to an uncontrolled one-arm open-label test. Thiswas because during the informed consent, subjects voiced
a strong desire to receive the Labdane containing food inorder to see if their knee discomfort could be ameliorated. In
consideration of the fact that knee cartilage does not improve,
but rather continues to deteriorate, the study methodology
was modified.
Besides the ethical considerations, it was concluded
that the purpose of the test could be adequately achieved bycomparing it with the VAS values from the beginning of thestudy to the final evaluations.

Japan) was used for the statistical analysis. The data analysis
was conducted by Friedman test with Bonferroni correction.
The numerical values determined were: mean, standard
deviation or frequency, with a significance level of +/− 5%.

Results

Background of test subjects

Of the 54 test subjects, there was 1 male and 53 females.
Their ages ranged 48-88 years old with an average age of
64.6 ± 8.2 years.

Effectiveness of analysis

Analysis in all caseComparison of VAS scores relating to the enrollees’
knee discomfort was made between test food intake 0 week
(4.7 ± 2.2), 4 weeks (3.4 ± 2.3), 8 weeks (2.6 ± 2.3). In theanalysis, statistical differences were observed between 4
weeks (p < 0.001), 8 weeks (p < 0.001) and 0 weeks of intake(Fig. 2). Since the difference was statistically significant,subgroup analysis on age and gender was not performed.

Analysis of data

Analysis of target group
The full analysis set (FAS) excludes all study subjects
who did not consume the test food as well as those who
failed to report to the hospital for the specified period. Six
subjects dropped out due to non-consumption of the test
food and/or failed to report to the hospital for the specified
period, and 54 (1 male and 53 female) subjects were analyzed.
Consequently, 54 subjects completed the study and had thedata analyzed.
Analysis method
The results of VAS on knee joint discomfort were usedas evaluation indices, and the values ​​at 4 and 8 weeks werecompared with 0 week. SPSS Statics 26 (IMB Japan, Tokyo,

＊＊

7

＊

6

Visual analog scale (VAS)

Questionnaire survey
The discomfort of the knee joint was measured byusing VAS. VAS corresponds to a graphic rating method,which is a psychological rating system 7). VAS generally uses
a 10 cm line segment. VAS assesses the subjective degreeof a question item by marking it on a straight line. VAS is a
way of taking difficult to rate symptoms, such as pain, andquantitatively simplifying them into easy to understand, andeasy to measure judgments 8).

＊＊8

VAS score

consuming new health foods or continuous intake of foodfor specified health use. During the observation period, they
were instructed to generally conduct their life as before thetest as much as possible.

5
4
3
2
1
0
Week 0Week 4

Week 8Fig. 2. VAS evaluation average.

Results are expressed as mean ± SD, n = 54, * p < 0.05, ** p < 0.001 by
Friedman test. VAS, visual analog scale; SD, standard deviation.

Safety evaluation
No adverse events were reported by any study subjects
during the intake period. Under the test conditions, long-term(8 weeks) intake of the test food was considered safe.

Discussion
This study examined the effects that consumption ofwhite turmeric with labdane had on healthy adults withdiscomfort of the knee joint. In all cases, a significant
improvement was observed in the measured values of VAS
scores compared to the start of the test food intake to 4 and 8
weeks. The study results indicate the ingestion of the Labdanerich LTDT 0.065 mg/day alleviates knee joint discomfort.

_ 171 _

The Effects of a Labdane Type Diterpenoid on Knee Joint Problems

The reduction of discomfort in the knee joint was notablein subjects who took food containing the Labdane. Efficacy
was seen 4 weeks after ingestion, and it is considered that the
subjects felt a reduction in knee joint discomfort even earlier.
In this study, female subjects greatly outnumbered malesubjects 9 -11). This is thought to reflect the fact that there are
gender differences in epidemiological cases involving theknee joint and that women outnumber men in this category.
The subjects were considered elderly with an average ageof over 70 years. This resulted from the fact that individuals
often have knee problems caused by aging. Conversely,
younger persons with discomfort with knee joints have often
suffered from some kind of trauma or disease. As such, theyusually were already receiving treatment for their ailment. No
invasive evaluation methods were selected because the study
was designed for healthy subjects. I n addition, evaluation
using MRI, etc. was not performed because of patientmeasurement burden and test cost. Future studies will benecessary to further verify the effectiveness of the Labdane.
If it is possible to obtain an understanding of the subject andthe ethics committee, it is necessary to consider a study basedon objective evaluation criteria using a randomized parallelgroup comparison design. Furthermore, based on the findings
obtained in this study, it is necessary to verify the mechanismof action of the Labdane on the discomfort of the knee joint.
Labdane is contained in various plants as well as theJapanese white turmeric12-21). The effects reported for labdane
are as follows: antitumor effect 15), cytotoxicity 16), antibacterial
effect 17, 20), anti-inflammatory effect 18), α-glucosidase activity
inhibition 19, 21), lipase activity inhibition 21), and bloodcompatibility enhancement 20). In the evaluation of bloodcompatibility, the risk of thrombus formation is evaluatedby the index of hypercoagulation and platelet activation,
against which labdane acts suppressively. Furthermore, labdane
has recently been reported to have an inhibitory effect on
HA degradation 6). HA, in the joint cavity, has actions ofcartilage lubrication, anti-inflammation, and anti-glycation,
and, therefore, plays an important role in maintaining joint
homeostasis 22). When, based on these reports, estimating themechanism of inhibitory action for joint pain, the importantfactors are actions of anti-inflammation and inhibition of
HA degradation.
A person who has discomfort of joints often complainsof symptoms characteristic of neuropathic pain, where
GABAA receptors are involved 23, 24). GABAA receptor is oneof ion channel type receptors and ion channel built-in type
receptors, and the ligand is γ -aminobutyric acid (GABA), an
inhibitory neurotransmitter. Pain is often chronic, and it has
been reported that central sensitization mechanisms work
followed by overlapping psychological factors 25). That is, it
becomes sensitive to pain, which is generated by a stimulusthat normally does not cause pain (allodynia). As a result, thepain becomes wider and longer lasting 26).
Chronic pain excites sympathetic tone and vasomotor
nerves, causing vasoconstriction and muscle tone elevation.
Consequently, blood circulation deteriorates, leading to thegeneration of “ algesic substance.” Some of the LTDTs haveactions of platelet aggregation inhibition 27) and vascularsmooth muscle relaxing 27, 28), thus contributing to maintenanceof blood flow. It is necessary to verify the effects of labdane
on vascular smooth muscle.

It has been reported that sclareol and andrographolide,which are LTDTs, are effective for osteoarthritis (OA) 29) orrheumatoid arthritis (RA) 30, 31). Additionally, another report
showed the GABAA receptor modulation by Curcuma
kwangsiensis rhizome extract 32).
Under physiological conditions, GABA acts, via the
GABAA receptor, to suppress the nerve excitation. However,once peripheral nerves are damaged, microglial cells become
activated in the spinal cord, via activation of P2X4 (purinergic
receptor 4) receptor, and release brain derived neurotrophic
factor (BDNF). As a result, the effect of GABA releasedby tactile stimulation on secondary neurons changes from
inhibitory to excitatory, and accordingly tactile stimulation
causes stronger pain 33). These findings suggest that GABAA
receptor modulators may alleviate neuropathic pain 34), thatis interesting. The action of labdane on GABAA receptors
needs to be verified in the future.
In Japan, there are about 30 products bearing functional
food labeling that claim or imply relief of the discomfortof the knee joint. Most of them are chondroitin, HA, and/or cartilage components such as collagen or fatty acids suchas docosahexaenoic acid (DHA) and eicosapentaenoic acid
(EPA). However, low molecular weight compounds likelabdane are entirely new.

Conclusion
The statistically significant results of this study at 4 and/or 8 weeks indicated that healthy individuals, with knee joint
discomfort, experienced safe and effective relief after taking
0.065 mg/day of Labdane from the extract of the Japanesewhite turmeric.

Conflict of Interest Statement
The present study was partly supported by Veritas Co.,
Ltd., and Veritas Hanbai Co., Ltd.

_ 172 _Glycative Stress Research

References
1) The Japanese Orthopedic Association. Locomo Challenge!

The Japanese Orthopedics Society official recognition
locomotive syndrome prevention enlightenment site. http://
locomo-joa.jp, accessed on April 6, 2020. (in Japanese)
2) Yoshimura N, Muraki M, Oka H, et al. Cohort profile:
Research on Osteoarthritis/Osteoporosis Against Disability
study. Int J Epidemiol, 2010; 39, 988-995.
3) Nakamura K. Locomotive syndrome. Jpn J Geriat. 2012;
49: 393-4 01. (in Japanese)4) Ministry of Health, Labor and Welfare. 2013 NationalLife Survey IV. The situation of care. http://www.mhlw.
go.jp/toukei/saikin/hw/k-tyosa/k-tyosa13/dl/05.pdf. (inJapanese)5) Ministry of Health, Labor and Welfare website. About
Physical Activity Standards 2013 for Health Promotion
and Physical Activity Guidelines for Health Promotion(Active Guide). Press release material on March 18, 2013.
https://www.mhlw.go.jp/stf/houdou/2r9852000002xple.
html (in Japanese)
6) Komai K. White turmeric: Form and functional components.
White Turmeric Promotion Society. http://www.shiroukon.
com, accessed on April 6, 2020. (in Japanese)
7) Guilford JP. Psychometric Methods. McGraw-Hill, New
York, 1954.
8) Wewers ME, Lowe NK. A critical review of visual
analogue scales in the measurement of clinicalphenomena. Res Nurs Health. 1990; 13: 227-236.
9) Iyoda K, Iwata H, Okuizumi H, et al. Epidemiologicalsurvey on knee joint pain in the middle-aged and the elderly.
Orthopedic Surgery. 1995; 46: 1291-1294. (in Japanese)10) Muto Y, Ota (Fukushima) M, Koda M, et a l. An
epidemiological study on the relationship between the onsetof knee osteoarthritis, body shape and physical fitness.
Orthopedic Surgery. 1997; 48: 365-370. (in Japanese)
11) Sasaki H, Tsuda E, Hiraga Y, et al. Prevalence of nocturnal
pain and sleep quality in patients with knee osteoarthritis.
JOSKAS. 2014; 39: 667- 672. (in Japanese)12) Marlier M, Guellec GL, Lognay G, et al. Characterizationo f th ree labdane diter penes from Af ra momum
alboviolaceum. Planta Med. 1993; 59: 455-457.
13) Nakatani N, Kikuzaki H, Yamaji H, e t al. Labdane
diterpenes from rhizomes of Hedychium coronarium,
Phytochemistry. 1994; 37; 1383-1388.
14) Duker-Eshun G, Jaroszewski JW, Asomaning WA, et al.
Antiplasmodial activity of labdanes from Aframomum
latifolium and Aframomum sceptrum. Planta Med. 2002;
68: 642-644.
15) Abas F, Lajis NH, Shaari K, et al. A labdane diterpene
glucoside from the rhizomes of Curcuma mangga. J Nat
Prod. 2005; 68: 1090 -1093.
16) Chimnoi N, Pisutjaroenpong S, Ngiwsara L, et al. Labdane
diterpenes from the rhizomes of Hedychium coronarium.
Nat Prod Res. 2008; 22: 1249-1256.
17) Ghosh S, Indukuri K, Bondalapati S, et al. Unveiling themode of action of antibacterial labdane diterpenes from
Alpinia nigra (Gaertn.) B. L. Burtt seeds. Eur J Med Chem.
2013; 66: 101-105.
18) Chen JJ, Ting CW, Wu YC, et al. New Labdane-type
diterpenoids and anti-inflammatory constituents from
Hedychium coronarium. Int J Mol Sci. 2013; 14: 1306313077.

19) Ghosh S, Rangan L. Molecular docking and inhibition

kinetics of α-glucosidase activity by labdane diterpenes
isolated from tora seeds (Alpinia nigra B. L. Burtt.). Appl
Biochem Biotechnol. 2015; 175: 1477-1489.
20) Chakrabartty I, Vijayasekhar A, Rangan L. Therapeuticpotential of labdane diterpene isolated from Alpinia nigra:
Detailed hemato-compatibility and antimicrobial studies.
Nat Prod Res. 2019 May 28: 1-5.
21) YoshiokaY, Yoshimura N, Matsumura S, et al. α-Glucosidaseand pancreatic lipase inhibitory activities of diterpenes
from Indian mango ginger (Curcuma amada Roxb.) and its
derivatives. Molecules. 2019; 24(22): E4 071.
22) Ogura M, Takabe W, Yagi M, et al. Hyaluronic acid andarticular cartilage. Glycative Stress Res. 2018; 5: 12-20.
23) Honda K, Horikawa K, Ando S, et al. The spinal muscarinicM(1) receptors and GABA(A) receptors contribute to
the McN-A-343-induced antinociceptive effects during
thermal stimulation of mice. J Pharmacol Sci. 2008; 108:472- 479.
24) Migita K, Moriyama T, Koguchi M, et al. Modulationof P2X receptors in dorsal root ganglion neurons ofstreptozotocin-induced diabetic neuropathy. Neurosci Lett.
2009; 452: 200-203.
25) Graven-Nielsen T, Arendt-Nielsen L. Peripheral andcentral sensitisation in musculoskeletal pain disorders:An experimental approach. Curr Rheumatol Rep. 2002; 4:
313-321.
26) Suokas AK, Walsh DA, McWilliams DF, et al. Quantitative
sensory testing in painful osteoarthritis: A systematic
review and meta-analysis. Osteoarthritis Cartilage. 2012;
20: 1075-1085.
27) Wu TS, Chern HJ, Damu AG, et al. Flavonoids and entlabdane diterpenoids from Andrographis paniculata andtheir antiplatelet aggregatory and vasorelaxing effects.
J Asian Nat Prod Res. 2008; 10: 17-24.
28) Ribeiro LA, Alencar Filho EB, Coelho MC, et al. The
vasorelaxant effect of 8(17),12E,14-labdatrien-18-oic acidinvolves stimulation of adenylyl cyclase and cAMP/PKA
pathway: Evidences by pharmacological and moleculardocking studies. Eur J Pharmacol. 2015; 764: 363-371.
29) Zhong Y, Huang Y, Santoso MB, et al. Sclareol exerts
anti-osteoarthritic activities in interleukin-1β-induced
rabbit chondrocytes and a rabbit osteoarthritis model. Int
J Clin Exp Pathol. 2015; 8: 2365-2374.
30) Tsai SW, Hsieh MC, Li S, et al. Therapeutic potential ofsclareol in experimental models of rheumatoid arthritis.
Int J Mol Sci. 2018; 19: E1351.
31) Li X, Yuan K, Zhu Q, et al. Andrographolide ameliorates
rheumatoid arthritis by regulating the apoptosis-NETosis
balance of neutrophils. Int J Mol Sci. 2019; 20: E5035.
32) Schramm A, Ebrahimi SN, Raith M, et al. Phytochemical
profiling of Curcuma kwangsiensis rhizome extract, andidentification of labdane diterpenoids as positive GABAA
receptor modulators. Phytochemistry. 2013; 96: 318-329.
33) Tsuda M. Microglia-mediated regulation of neuropathic
pain: Molecular and cellular mechanisms. Biol Pharm
Bull. 2019; 42: 1959-1968.
34) Takano Y. Easing human pain: Challenges to a novel
therapeutic drug in neuropathic pain. Yakugaku Zasshi.
2014; 134: 997-1005. (in Japanese)_ 173 _