**2. The need for cultivation and conservation of African medicinal plants for pharmaceutical research**

The emergence of the COVID-19 pandemic has demonstrated that the African continent has made no adequate preparation for the prevention of present and future diseases through systematic advanced biomedical research. Therefore, to prevent future emergencies, there is a need for rapid investment into agro-medicinal plant cultivation. The medicinal plants may provide the following categories of medicinal agents:

a.They provide raw materials for the pharmaceutical industries.


In the recent past, there is a growing difficulty in obtaining some medicinal plant species from the wild source due to extinction, scarcity and over-exploitation. Therefore, where there is difficulty in obtaining a medicinal plant; then cultivation of medicinal plants seems to be the best and the most reliable alternative for their conservation. Botanical gardens are important agencies for ensuring their conservation [9].

According to Osemeobo [14] who observed, since the medicinal plants on regular trade are on the decline, stakeholder's participation is required in plant species rehabilitation in the forests. This can be achieved through the establishment of *ex situ* gardens which may sustain the medicinal plant trade.

The continued commercial exploitation of these plants has resulted in receding the population of many plant species in their natural habitat. It is therefore, necessary to initiate systematic cultivation of medicinal plants to conserve biodiversity and to protect endangered species [15].

Medicinal plants harvested from the wild are of immense importance for the well-being of millions of people around the world. They continue to provide both reliefs from illness and a source of income. The loss of habitat, combined with overharvesting, threatens the survival of many of these plant species.

Furthermore, the rapid extinction of medicinal plants from the wild threatens drug discovery [8]. The more the medicinal plants become extinct, the more difficult it becomes to get these plant species for pharmaceutical research and drug development [8]. The medicinal plants used by the pharmaceutical industries are mostly harvested from the wild [15].

Plants play a pivotal role for the survival of man and other animals [9]. They are the primary producers that sustain all other life forms, regulate air and water qualities, shape ecosystems and control the climate [15]. They provide food, medicine, clothes, shelter and the raw materials from which other products are made. These benefits are widely recognized but poorly understood [9]. Thus, plants are both a vital part of the world's biological diversity and plants are an essential economic resource for human existence [9].

Medicinal plants have been used by mankind for millennia; their use is as old as humanity itself. The range of plant species used for healing purposes is vast. Belinda [9] asserted that "cures as yet undiscovered may exist in plants as yet undescribed". It has been reported by the WHO that over 80% of the World's population depends mainly on plants and plant extracts for health care [16]. It has been estimated that in developed countries like the United States (US), plant drugs constitute about 25% of total drugs. In China and India, they constitute about 80%. It has been estimated that over 250,000 higher plant species occur on earth, with more than 80,000 species reported to have some medicinal values while around 5000 species have specific therapeutic values [15].

Medicinal plants can be classified according to the part used (as a whole plant, root, bark, stem, leaf, fruit, flower and seed), habit (as grasses, sedges, herbs, shrubs, climbers and trees), habitat (as tropical, sub-tropical and temperate) and therapeutic value (as antimalarial, anticancer and anti-inflammatory, antibacterial) [15].
