Page 79 - Pharmacognosy-II (06-PG 303)

The use of Cannabis dates back more than four centuries, it has been also used as a source of fiber and ropes
for clothing.

The action of Cannabis as a whole and many of its individual compounds has been investigated in detail
over the past years.

Cannabis is most widely known as a psychoactive drug, THC appears to contribute most significantly to the
observed effects.

Important remark: The biological effects of cannabinoids are mainly mediated by two members of the

G-protein-coupled receptor family, cannabinoid receptors 1 (CB1R) and 2 (CB2R). These receptors are a
part of endocannabinoid system which is involved in a variety of physiological processes

including appetite, pain-sensation, mood, and memory. Cannabinoid receptors are activated by three major

groups of ligands: endocannabinoids, produced by the mammillary body, plant cannabinoids (such

as Tetrahydrocannabinol, produced by the cannabis plant); and synthetic cannabinoids. All

of the endocannabinoids and phytocannabinoids (plant based cannabinoids) are lipophilic, such as fat

soluble compounds.

Δ9-THC is the principal psychoactive constituent.
Δ8-THC is almost as active but is only present in the plant in small amounts.

Cannabinol is less potent.
Cannabidiol, lacks the psychotropic properties (presents a modulating effect on Δ9-THC

psychoactive activity) and has anticonvulsant and possible analgesic and anti-inflammatory effects.

Cannabichromene may enhance THC activity and has antifungal, antimicrobial and anti-
inflammatory activity.
Cannabis has been also used as a source of fiber and ropes of clothing. Medicinal properties of
cannabis were recognized some 5000 years ago. In the mid-nineteenth century it was used in Europe
as a hypnotic, anticonvulsant, analgesic, antianxiety and antitussive agent. Over many years it fell
into disuse in human and veterinary medicine, and because of its narcotic properties importation into
many countries became illegal.

Therapeutic actions of Cannabis

• Promising results on the use of Δ9-THC for the relief of nausea and vomiting caused by
cancer chemotherapy led to its use in the USA as an antiemetic. It is also employed to
stimulate the appetite of AIDS patients. It can be prescribed in the UK under license on a

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