Quantitative Chemobiology: A Guide into the Understanding of Plant Bioactivity

A considerable effort during several decades produced only modest knowledge on the chemical composition of the Brazilian flora.¹ The fact is even less easy to understand, if it is considered that the value of medicinal products derived from tropical plants surpassed in recent times US$ 6 billion per annum.² Should it really be impossible to find ways and means to recover this enormous wealth in adequate time, or at least to design suitable process with such objectiveness? To face such problems is rather urgent. Already drug discovery is going down and disease resistance is going up. Today, more than 30,000 diseases are clinically described. Less than one third of these can be treated symptomatically, and only a few can be cured.³ Meanwhile some pharmaceutical concerns continue to announce great expectations of "miraculous cures" based on medicinal plants. Others are looking for natural products of novel molecular skeletons from a variety of marine organisms. However, as yet, no compounds from the sea have advanced to commercial use as a chemotherapeutic agent.⁴ On the other hand, the quantitative structure-activity relationships (QSAR) approach has demonstrated great possibilities in drug-designs and drug-target interactions. Finally, synthetic, specifically projected, DNA-based wonder drugs are expected to alleviate human suffering in the future.

Thus, the first problem leads us to a second reasonable challenge: Is the study of medicinal plants really subject to scientific control?

Brazil, the country of contrasts and paradoxes, is ideally suited to meet this biological challenge! The more than 8.5 million km² shelter an enormous biological and cultural wealth. Besides big industrial populations there exist small native tribes that remain in their original state without any contact with the rest of the country, such as the Korubos tribe on the margins of Ituí river, Javari Valley, Amazonas, frontiers of Peru and Colombia.⁵ Out of 210 Brazilian indigenous populations, 55 live in similar social isolation since the time of colonization, 500 years before present.