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Journal of Thai Traditional & Alternative Medicine Vol. 7 No. 2 May-August (Supplement) 2009 ÒÒ

OP-40

Factors Affecting Cannabinoids Content for Classification of Cannabis Plants

in the North of Thailand

1 2 3 4
Surapol Natakankitkul , Prapatsorn Tipparat , Pipop Chamnivikaipong , Sirot Chutiwat ,
5
Maitree Suttajit
1
Faculty of Pharmacy, Chiang Mai University, Chiang Mai, Thailand *E-mail: surapolhsri@gmail.com
2
Regional Medical Science Center, Chiang Mai (RMSC), Chiang Mai, Thailand
3
Northern Office the Narcotic Control Broad, Muang, Chiang Mai, Thailand
4
Queen Sirikit Botanic Garden, Botanical Garden Organization, Chiang Mai, Thailand
5
School of Sciences and Technology, Naresuan University, Phayao, Thailand

Rationale: Cannabis plants including marijuana and hemp belong to the same family Cannabaceae and
genus Cannabis. The high variability of characteristics used for classified species are composition of cannab-
inoids, commonly divided into a drug type, an intermediate type and a fiber type. Although hemp cultivation
was primarily prohibited due to be enforced as a schedule V controlled substance in the Thailand Narcotic Act.
The study of the fluctuation of cannabinoids due to environment factors and cultivation methods would be
advantage for establishing the guidelines for distinguishing hemp from marijuana.
Objective: To study the factors affecting the variations on the amounts of cannabinoids in hemp grown in
the north of Thailand, including environment factors and cultivation methods.
Methodology: Hemp samples were collected both from field trials supported by The Botanical Garden
Organization in Chiang Mai and Pitsanulok provinces. The Cannabis plants grown by hill tribes traditional way
were also collected from local farmlands by the supporting of Institute of Survey and report, Office of the
o
Narcotics Control Board. All samples were dried at 40 C for 48 hours, ground into powder and stored in the light
o
protection plastic bag in refrigerator at 5 C until analysis. The methanolic extract was analyzed for three major
cannabinoids: delta-9-tetrahydrocannabinol (THC), cannabidiol CBD and cannabinol CBN by gas chromatogra-
phy. Multiple regressions analysis was performed to verify the relationships of the environmental factors such as
the elevation of each cultivated areas, average temperature, amount of rainfall, and relative humidity to the THC
and CBD content.
Results: Both THC and CBD were related to stage of plant development which highest in flowering stage.
The range of THC at flowering from field trials were 0.682 - 0.833 % w / w by dry weight and the ratio of CBD:
THC were 0.56 - 1.07, respectively. While the range of THC and the ratio of CBD: THC contents at flowering
from local farmlands were 1.176 - 1.330 % w / w by dry weight and the ratio of CBD: THC were 0.40 - 0.41,
respectively. The CBN content was found less than 0.005 % w / w in all samples. Whereas, means THC and CBD
contents in marihuana (3 seized samples) were 2.237 and 0.12 %w/w, respectively, and the ratio of CBD: THC
was less than 0.05. The plant height was significantly (p<0.05) correlated to diameter of stem, location (elevation
of growing area) and stage of plant development.
Conclusion: The results showed that the environmental factors and cultivation methods were influenced
the THC and CBD contents. The Cannabis plants were classified as between intermediate type and fiber type.
It will be useful to establish the guidelines for distinguishing hemp from marijuana by legislating and regulating
the cultivation of hemp for industrial fiber, medicine, dietary supplements and cosmetics in the future.