Cross-cultural Medical Ethnobotany

Nat Bletter (CUNY Plant Sciences/NYBG)

Abstract

    Ethnobotany has proven to be a valuable method to find new herbal medicines and plant-derived drugs, but given limited resources, thousands of plants to consider, and many cultures to investigate, where can we focus our attention? With only about 0.5% of the known 250,000 species of angiosperms examined for medicinally active compounds, 25% of all pharmacy-prescribed western drugs being derived from plants, and a more than $25 billion yearly worldwide market in plant-based medicines, this is obviously a fruitful area to explore. Techniques are needed to narrow in on the plants with the highest medical potential, however. Building on previous work in quantitative ethnobotany, a new way to determine plants with high medical potential that are worthy of further investigation is being explored. High-potential candidates are picked by finding related plants from unrelated cultures that are used to treat the same or related diseases. The relations between cultures, plants, and diseases are derived from phylogenetic trees where feasible. This is a method of corroborating that the plants have biologically active compounds in them, and it avoids problems in previous similar techniques where plants are grouped by family. This technique is then used to analyze and compare herbal remedies for diabetes, eczema, asthma, malaria, and uterine fibroids collected from herbalists from different traditions (Ayurvedic, Chinese, European, Dominican, and Cuban) around New York City, as well as Itza and Qeqchí Mayan groups in Guatemala. 
Flower Power Shop
Fig 1. Flower Power herb shop in New York's East Village.
Chinatown Herb Shop
Fig 2. Reyes Botanica, a Dominican herb shop in Washington Heights, NY.
Chinese herbs
Fig 3. Herbs prescribed for diabetes and eczema by Chinese herbalists.

Fig 4. Endangered Chinese Pangolin, whose hide was found in several Chinese eczema treatment mixtures.

Field Work

   To gather data on herbal remedies from different cultures to fill in this theory, 14 herbalists from Ayurvedic, Chinese, European, and Latino traditions from all over Manhattan, NY (see Fig. 1 & 2) were asked for their treatments for the auto-immune diseases eczema and Type I diabetes (early onset). See Fig. 3 for some of the herbs gathered and Fig 4. for the endangered Chinese Pangolin found in one treatment.
    To reach a less disturbed indigenous culture, 8 healers or  curanderos from the Itza and Qeqchí Maya groups (Fig. 5-7) in the north of Guatemala (Fig. 8) were interviewed for their treatments for diabetes, eczema, asthma (all auto-immune), malaria, and uterine fibroids related to menopause.
    Several interesting plant families were pinpointed that deserve further research because of their use for several diseases in several distant cultures. Plants closely related to qinghao from China were found in Guatemala, both used to treat Malaria, drawing interest to this group. 
Flower Power Shop
Fig 5. César with vine used to make Panama hats.
Chinatown Herb Shop
Fig 6. Qeqchí mayan herbal healer Domingo Xol from El Corozal, Guatemala.
Chinese herbs
Fig 7. Doña Irma Chayax, an Itza Mayan, in front of the women's collective medicinal plant garden she help create in San Jose, El Peten, Guatemala.

Fig 8. Map of the El Peten region in Northern Guatemala, home of the Maya Biosphere Reserve.

Theory

    The ultimate goal of this research is to develop a formula that will give us a measure of the relative medical potential of each plant that will tell us for which plants it is more worth undertaking the lengthy process of exploring their phytochemistry and biological mechanism than all the other medicinal plants we have found. This is done by linking the three evolutionary trees or phylogenies of plants, cultures, and diseases (see Fig. 9). We assume that the less related two cultures are, the more likely their discovery of related plants to treat related diseases is an independent event and should increase the plants medical potential.


Fig 9. The three evolutionary trees of  plants, cultures, and diseases that are linked to determine a plants medical potential.


Fig 10. One of the numerous Guatemalan butterflies  pollinating a marigold relative (Tagetes sp.) near the ancient Mayan ruins of Tikal. This plant is often used as a natural mosquito repellent.

Other Info

My advisor at the NYBG Doug Daly
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© All photos and text copyright Nat Bletter, 2002, unless otherwise noted.