Cross-cultural Medical Ethnobotany
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 Q’eqchí Mayan
groups in Guatemala.
Fig 1. Flower Power herb shop in New York's East Village.
Fig 2. Reyes Botanica, a Dominican herb shop in Washington
Fig 3. Herbs prescribed for diabetes and eczema by Chinese
Fig 4. Endangered Chinese Pangolin, whose hide was found
in several Chinese eczema treatment mixtures.
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 Q’eqchí
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.
Fig 5. César with vine used to make Panama hats.
Fig 6. Q’eqchí mayan herbal healer Domingo Xol from
El Corozal, Guatemala.
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.
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
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.
at the NYBG Doug Daly
© All photos and text copyright Nat Bletter, 2002, unless otherwise