Influence of photoperiodism on cannabinoid content of Cannabis sativa L.




Author: J.R. VALLE,, J. E. V. VIEIRA, , J.G. AUCELIO, , I. F. M. VALIO
Pages: 67 to 68
Creation Date: 1978/01/01

Influence of photoperiodism on cannabinoid content of Cannabis sativa L.

J. E. V. VIEIRA, 1
Department of Biochemistry and Pharmacology, Escola Paulista de Medicina, Caixa Postal 20372, 01000 São Paulo, S.P., Brazil


Cannabis sativa plants submitted to 10 and 12 hours of natural light showed different content in cannabinoids. An increase of exposure to natural light of only 2 hours a day, at least, doubled the average amoung of THC, but decreased that of cannabichromene.

To study the influence of light on flowering of Cannabis sativa (Valio and Valle, 1973), seedlings and rooted cuttings obtained from hemp seeds cultivated in plastic pots were submitted to different photoperiodic treatments. Lots of 10 plants were used per treatment and all the pots were moistened every day with tap water and every 15 days they were given a complete Hoagland's nutrient solution. Temperature ranged from 17 to 34 °C.

During the 65 days period all plants on the 8-, 10- and 12-hour photoperiods flowered. Plants on 14- and 16-hour periods did not produce visible flowers. The flowering tops and leaves from plants with 10 (A) or 12 hours' (B) exposure to natural light in the glasshouse were collected, dried at room temperature, separated from seeds and fibres and powdered. Powders (A) and (B) were extracted with chloroform (Fairbairn and Liebmann, 1973) and their content of cannabinoids determined through gas chromatography by employing basically the procedure of Lerner and Katsiaficas (1969). Presence of tetrahydrocannabinol, cannabichromene and cannabinol was shown in both samples and quantitative estimation of these cannabinoids appears in the table.


Photoperiodism and cannabinoids content in Cannabis sativa L. a


Daily natural light in glasshouse


10 hours (A)(g %)

12 hours (B)(g %)

1.26 ± 0.08
2.94 ± 0.09
0.44 ± 0.04
0.25 ± 0.02
0.96 ± 0.09
1.36 ± 0.12

aAverage and standard deviation.

Deceased February, 1973.

Kimura and Okamoto (1970) have studied the seasonal influence which interferes with the content of some constituents in differents parts of the plants.

From our data we may conclude that an increased length of natural light of only 2 hours a day at least doubled the average content of THC and decreased significantly the average content of cannabichromene. Cannabinol content, however, did not reveal significant difference.


Fairbairn, J.W., and J.A. Liebmann. The extraction and estimation of the cannabinoids in Cannabis sativa L. and its products. J. Pharm. Pharmacol., 25, 150, 1973.

Kimura, M., and K. Okamoto. Distribution of tetrahydrocannabinolic acid in fresh wild cannabis. Experientia, 26, 819, 1970.

Lerner, M., and M.D. Katsiaficas. Analytical separation of mixtures of hallucinogenic drugs. Bulletin on Narcotics, XXI:1, 47-51, 1969.

Valio, I.F.M., and J.R. Valle. Influence of photoperiod on flowering of Cannabis sativa. Ciência e Cultura (São Paulo), 25, 533, 1973.