Disturbance Pharmacopoeias: Medicine and Myth from the Humid Tropics

Abstract

The much-publicized quest for miracle drug plants in tropical rainforests has provided compelling support for the preservationist agenda. This article questions the assumptions that underpin this claim, particularly the myth that pristine forest represents the primary repository of nature's medicinal providence. After tracing colonial European efforts at medicinal plant discovery, intellectual property exploitation, and plant transference and acclimation, I review the recent resurgence of scientific interest in tropical folk pharmacopoeias. In spite of the image marketed by environmental entrepreneurs, the medicinal foraging preference of rural tropical groups is largely successional mosaics of their own creation—trails, kitchen gardens, swiddens, and forest fallows. Focusing on the subsistence transition from hunting and gathering to small-scale cultivation, I propose that disturbance pharmacopoeias are the logical outcome of changing subsistence strategies, ecological processes, and disease patterns. Salient, familiar, accessible, and rich in bioactive compounds, anthropogenic nature represents the ideal tropical medicine chest. Whereas bioprospecting enterprises carried out during the colonial period and at present employ similar rhetoric—deadly disease, miracle cures, and fantastic profits—these endeavors were in the past and continue to be buttressed by fictitious notions of virgin tropical nature and the mysterious healing powers of its “primitives.”Key Words: pharmacopoeia, tropical rainforest, ethnobotany, medicinal plants, human ecology.

Acknowledgments

I wish to thank my many collaborators in Brazil and Borneo, especially the healers and the healed, who contributed significantly to the ideas I present here. I also thank the three anonymous reviewers, whose suggestions for improvement were insightful and valuable. Funding for field work was provided by grants from the National Geographic Society (7820–02), a National Endowment for the Humanities Summer Stipend, a Fulbright Research Fellowship to Brazil, and several Faculty Research Grants from California State University, Fullerton.

Notes

Sources: Farnsworth 1988; Soejarto and Farnsworth 1989; Balick and Cox 1996.

1. The Material Medica saw at least seventy-eight separate European editions during the sixteenth century (Stannard 1999).

2. This quest was fueled in part by ancient determinist beliefs regarding torrid-zone nature and culture. The hot and humid climates of Africa and Asia may have hobbled cultural development, but these same landscapes were also fonts of crucial medicinal imports—aloe, camphor, cinnamon, ginger, clove, and many others (Glacken 1967; J. I. Miller 1969).

3. Guaiacum was the first plant species of New World origin to be reported in Europe (Shaw 1992, 17). Native to the Antilles and southern Florida, this medicinal was being touted by 1510 as the principal weapon against syphilis, which appeared in Europe soon after Columbus's first voyage.

4. For reviews of other important nonmedicinal extractive resources, see Dean 1995; Cleary 2001.

5. This likely reflects long-standing notions regarding the Dark Continent as an intellectual backwater, and African ethnobotanical traditions as too mired in witchcraft and the occult to be of practical medicinal benefit (Jarosz 1992; Carney and Voeks 2003).

6. The humoral doctrine, which continues to be applied in folk medical systems (E. Anderson 1987; Voeks 1995), holds that health problems are minimized by the individual establishing a state of equilibrium with the principal elements—earth, wind, water, and fire—as well as their states of environmental opposition—hot and cold, or wet and dry (Glacken 1967,;9–12; Jouanna 1998).

7. Because these include all plant-derived compounds, the dollar value of tropical medicinals would be some fraction of these figures.

8. In a subsequent publication, Mendelsohn and Balick (1997) revised the dollar value to drug companies down to zero, noting that “undiscovered drugs have little market value because they are expensive to find” (p. 328). Nevertheless, the value to society of unknown drug plants, they estimate, is still roughly US$109 billion.

9. The random testing of yew bark (Taxus brevifolia) in Oregon in the 1960s as part of the National Cancer Institute's plant screening program, and its eventual development into the powerful anticancer treatment taxol in the 1990s, represents a notable exception (Walsh and Goodman 1999).

10. See for example: Paul Cox, Nafanua: Saving the Samoan rainforest; Norman Myers, The primary source: Tropical forests and our future; and Mark Plotkin, Tales of a shaman's apprentice.

11. Ethnobotanists working in the tropical realm often adopt the 1-hectare plot census methodology in order to standardize their results. Because alpha diversity is too high to measure all the plant species, researchers normally include only trees and lianas that are 10 cm in diameter-at-breast-height or greater. Remaining lifeforms—herbs, shrubs, treelets, and most vines—are excluded from their censuses (see Balee 1986; Galeano 2000).

12. Forager subsistence in tropical forests, according to the “wild yam hypothesis,” would have been possible only if carbohydrates could be acquired from neighboring sedentary cultivators (Hoffman 1986; Headland 1987; Bailey et al. 1989; Cormier 2003). Purely foraging societies could only have permanently occupied the forest after the entrance of cultivators. Recent research suggests, however, that late Pleistocene/early Holocene foraging predated horticulture by several millennia in most tropical forest biomes (Piperno and Pearsall 1998; Meggers and Miller 2003; Mercader 2003).

13. Among the valid criticisms of Brown's results was that many of the small-scale cultivators in his inventory inhabit speciose tropical regions, but most of the hunter-gatherer records are for groups occupying species-poor temperate zone habitats (Bulmer 1985; Headland 1985).

14. Healthy hunter-gatherer profiles are also attributed to high levels of physical activity, intake of fiber-rich foods, and low triglyceride levels (see M. Miller 1999; Milton 2000). These are not relevant to this discussion, however, because these properties are shared by small-scale cultivators.

15. This is not to suggest that second-growth forest sites are not species rich. As Guariguata and Ostertag (2001) note, overall woody plant richness can approach that of old-growth forest in a few decades (see also Voeks 1996a). However, because the size of individual trees in second-growth forest is usually smaller, their number per unit area is higher than in old-growth sites.