**1. Introduction**

Peru is cataloged as a megadiverse country due to its great diversity of species, particularly in plants [1, 2]. This diversity is attributed to the large number of eco-regions present in our territory [3], which were originated by their particular geologic evolution [4]. The Peruvian Amazon includes a large proportion of this richness in plant species, and several are endemic to this region [5, 6]. The diversity, however, remains underestimated because until now a complete and updated inventory of plant species is lacking, but some estimates suggest that more than 50% of plant species are unknown to science [7, 8].

Similarly, there are many gaps in the scientific knowledge of medicinal plants of the Peruvian Amazon. These gaps are evident at various knowledge levels from the inventory of medicinal plants and their taxonomic identification, the bioactive phytochemicals produced, the mechanisms of action of the bioactive phytochemicals, and the metabolic pathways involved in the biosynthesis of bioactive phytochemicals. In part, these gaps in the scientific knowledge can be attributed to several factors: (1) the ethnopharmaceutical information has been obtained from few ethnic groups (probably <10%); (2) the majority of ethnopharmaceutical surveys have been focused on plant species to treat protozoal diseases, with particular emphasis on malaria and leishmania [9–12]; and (3) the research centers in the Peruvian Amazon generally lack trained scientist, laboratory equipment, and standard methods to perform bioassays for the discovery of bioactive phytochemicals against diabetes, inflammation, hypertension, cancer, infectious diseases (viral, bacterial, and fungal), and other health problems. Consequently, it is fundamental to implement strategies to surpass these limitations and to close these large knowledge gaps.

Parts of the problems mentioned are addressed in this book chapter that consists of six topics. The first topic "The diversity of plants in the Peruvian Amazon" describes the diversity of species reported for the country and the Peruvian Amazon and are mentioned the possible factors involved in light of current knowledge. The second topic "Medicinal plants and indigenous people in the Peruvian Amazon" highlights information about medicinal plants and ethnic groups. Relevant information of the recently elaborated partial database of medicinal plants is also discussed. The third topic "Some bioactive phytochemicals identified in medicinal plants" presents structures of bioactive phytochemicals against cancer, inflammation, diarrhea, malaria, and diabetes. The fourth topic "Mechanism of action of select bioactive phytochemicals" explains the molecular bases of the mechanisms of action of well-characterized phytochemicals such as taspine, crofelemer, mitraphylline, quercetin, linalool, and bixin. The fifth topic "Biosynthetic pathways for relevant bioactive phytochemicals" describes and provides graphically key metabolic pathways involved in the biosynthesis of quercetin, linalool, and bixin. The final topic "Strategies for the sustainable use of medicinal plants" recommends the adoption of strategies to accelerate the generation of scientific knowledge that permits a sustainable exploitation of the medicinal plants in the Peruvian Amazon.

#### **2. The diversity of plants in the Peruvian Amazon**

The plant diversity in the Amazonian lowland rain forest is astounding. This diversity was recently demonstrated with a large-scale taxonomic inventory, which identified 14,003 species; 1788 genera; and 188 families of seed plants, in which 50% of these species can reach ≥10 cm stem diameter at breast height (DBH). More than 52% of seed plant species diversity in this region include shrubs, small trees, lianas, vines, and herbs [1]. The Peruvian Amazon includes ~39% (5401 species) of these species. Also, a previous study showed that a forest near to Iquitos is the most species-rich in the world, with ~300 species ≥10 cm in DBH [2]. In addition, it is estimated that ~17,143 plant species are circumscribed within the national boundaries [13], and approximately 13% of these plant species are endemic to the Peruvian Amazon [5, 6]. It is speculated, however, that only 60% of the Peruvian flora has been identified [7]. Consequently, Peru is considered to be one of the 17 megadiverse countries, a global center for species

*Medicinal Plants of the Peruvian Amazon: Bioactive Phytochemicals, Mechanisms of Action… DOI: http://dx.doi.org/10.5772/intechopen.82461* 

 richness of plants and other organisms [14]. This peculiarity is attributed to the most Holdridge life zones (containing 84 of the 107 eco-regions of the world) that possess our country [3], which was determined for their particular geologic evolution [4].
