by Dr. Henry Lowe, Professor Errol Morrison O.D.
The sex of the plant is usually determined when flowering begins. The male flowers (inflorescence) have several individual flowers on branches up to 20 centimetres long. The female flowers do not project beyond the surrounding leaves.
The male plant is not regarded as being pharmacologically active. In fact, it is called ‘mad’ because of its relatively low THC content and the headaches it can cause when smoked.
Cannabis farmers have suggested that in an average field approximately 40 percent of the plants are male and 60 per cent are female. They have also stated that the male plants need to be uprooted and destroyed at an early stage of development (as soon as flowering begins), otherwise the crop will be contaminated and will result in low yields. However, the male plant normally dies much earlier than the female, especially after fertilization.
The cannabis plant is typically covered with tiny hairs (called trichomes), some of which are glandular and produce and contain resinous substances, which have been identified chemically as THC and non-narcotic cannabinoids and cannabidiols. The resin typically contains high THC concentration and is mostly found on flowers.
These are often used, with the aid of a microscope, to identify the plant. The unfertilized flowers from the female plant are highly prized and are called ‘sinsemilla’ (which means without seeds).
The female flowers, leaves and resin are the materials usually harvested for non hemp purposes, and in general different harvesting methods are used for these products depending on whether they are used for ‘narcotic’ or medicinal purposes. Scientists have determined that marijuana may contain up to 10 per cent of THC, hashish up to 15 per cent and hash oil up to 65 per cent.
Storage conditions (heat and light reduce the THC content) and the age of the materials have been found to influence the quality of the material, mainly because of chemical changes to the THC. Usually, a one-year old material will on average have lost only 10 per cent of its potency, but after two years, without storage, it maintains only about 10-12 per cent of its original potency. However, when stored in a cool, dark area its potency can be effectively maintained for about two years, but begins to fall off rapidly thereafter.
The Chemistry of Cannabis
Cannabis has been described as one of the most studied plant materials in history. A recent count has indicated that more than 7,000 scientific papers have been published on this subject area, along with related pharmacological activities. This is not surprising since the phyto-chemistry of Cannabis sativa has so far identified more than 400 different chemical compounds, with a variety of interesting chemical, pharmacological and physiological principles.
Of these many chemicals identified, the one that has been of major interest is THC, which was first isolated in 1964. THC and its relatives (over 60 compounds) are chemical compounds typically with 21 carbon atoms, which are referred to as cannabinoids. These cannabinoids are exclusively found in cannabis. However, interestingly, several non-cannabinoid compounds have been found in Cannabis sativa, but these are generally widely distributed throughout the plant kingdom. They include enzymes, glycosides, vitamins, acids, alcohols, amino acids, proteins, sugars, alkaloids and terpenes. It is believed that it is these terpenes that attract sniffer dogs to marijuana.