It is estimated that between 25 and 35% of new chemical entities for all diseases worldwide, approved between 1981 and 2006, were from natural products. And around 120 prescription drugs sold globally originate from rainforest plants.
Estimates of the number of global higher plant species vary between about 215,000 and 500,000. file:///C:/Users/harry/Downloads/ehp109s-000069.pdf A 2016 report by the Royal Botanic Gardens Kew estimated that there are 390,000 plant species. Again predictions vary but 1–15% of plant species have been screened for their medicinal potential. This leaves out other potential uses such as a food or material.
The Pacific yew (type of tree) was regarded commercially useless until it was found to contain the compound taxol – a substance that kills cancer cells. One study estimated that 12.5% of plant species documented worldwide have medicinal value. file:///C:/Users/harry/Downloads/Medicinal_and_aromatic_plants_in_agroforestry_syst.pdf According to their predictions of Earth having 422,000 plant species, this would mean that there are 52,750 plant species of medical importance.
Of anticancer drugs available between 1940 and 2002, 40% were from natural products or natural derived products. Quinine, which is on the WHO’s essential medicine list and used for treating malaria, comes from the bark of a Cinchona tree, found in the tropical forests of the Andes, South America. And the Calabar bean which comes from the tropical forests of Africa is used to treat glaucoma (a condition where the nerve that connects your eye and brain becomes damaged and can lead to vision loss).
Since the 1990s pharmaceutical industries aren’t pursuing naturally derived medicines as much as synthetic ones. According to one study, synthetic drugs can have greater or quicker effects than natural based medicines, but have increased side effects
Furthermore, medicines from plants can have totally unexpected breakthroughs. The discovery of taxol in the Pacific Yew, found by a random screening program in the 1960’s, led scientists to find a previously unknown method of anti-cancer activity in 1979.
Since the 1990s we have lost roughly 7.5 million hectares of tropical forests a year and if current rates continue, NASA’s (North Atlantic Space Agency) Earth Observatory predict the world’s rain forests will be gone within 100 years. Current extinction rates are 100-1,000 times higher than natural background rates and as many as 15,000 medicinal plants are under threat. If we continue humanity will potentially lose many future medical cures.