Blue Zone of Sardinia: The Expedition Continues
I'm on expedition in the mountains of Sardinia visiting communities renown for the exceptional number of centenarians. Here, I share insights into the scientific processes used on the expedition.
Things have been busy since my last newsletter, each day more packed than the last! Following Seulo, we traveled to Santa Maria Navarrese to set up a home base for processing plant samples being collected in various sites in communities of the Ogliastra region of Sardinia. Based on the coast, Santa Maria Navarrese has the advantage of being a uniting point for the roads that branch out, curving into the mountains.
I was so very fortunate to be connected with the Blue Zone Observatory group, established by the physician/scholar Dr. Gianni Pes, who originally discovered this phenomenon of a concentrated cluster of longevity communities. With help of the network, I was introduced to several local mayors, forest conservationists, shepherds, farmers, and elders! My days have been split between conducting preliminary interviews and collecting plant samples for deposit at the Herbarium of the Universita degli Studi di Sassari, where I am hosted as a visiting professor, and Emory University Herbarium, which I curate.
For an update on the tragic situation regarding the Duke Herbarium, read this recently published article in the Washington Post: “What dead flowers tell us about the future of life on Earth”
In case you are new to the newsletter and missed my earlier posts on herbaria and their critical importance to research on biodiversity, climate change, drug discovery, and more—please take a moment to read these prior pieces:
Herbaria in Peril (Nature’s Pharmacy Substack)
Nature’s Last Hope (Nature’s Pharmacy Substack)
My article in the Washington Post: Scientists depend on these for research. Let’s preserve them.
Wild Medicinal and Edible Plants of Ogliastra
Sardinia is home to 341 plant taxa that are endemic to the Tyrrhenian Islands—representing 15% of the total native flora. An astounding 195 of these—8% of the total native flora—are exclusive to Sardinia. The term “endemic” refers to plants restricted to growing in only certain parts of the world. The mountainous region of Ogliastra (location of a cluster of longevity communities) is particularly rich in biodiversity of native and endemic flora, making it a wonderful place to hunt for interesting and understudied plants. Moreover, there are many ethnobotanical uses of these species by community members for both food and medicine. My big question is, could there be a connection between the consumption of some of these wild species and healthy aging?
The scope of this first visit—a pilot study—is to establish a collaboration network with local scientists and communities, capture the lay of the land, see what some of the most common plant use practices are, and then write a grant to support a much larger, multi-year, multi-investigator project to pursue together with my local Sardinian collaborators. For now, I’ll share a bit about what the plant collecting process looks like.
Collection of Wild Flora
It is important to note that the work described here is for scientific purposes and entails permissions and permits for access and shipping of samples as well as collaborations with local scholars. This is not something members of the general public would do.
As an ethnobotanist and someone who documents traditional uses of plants and investigates their pharmacological properties and chemical makeup, the types of data I collect range from qualitative interview data to the collection of physical specimens for analysis in my laboratory. Interviews, frequently undertaken out where the plants are on hikes, entail recording the following details:
Local name of the plant
Details on when it is harvested, which parts are used, and how it is prepared
Details on uses (medical, food, ritual, veterinary, etc.) of the plant
Then, physical specimens are taken for herbarium deposit and lab analysis. For each species collected, additional data is gathered such as photos of the plant and its features, a description of the growth habitat and notation of other species growing nearby, GPS coordinates (latitude, longitude, elevation), notations on the plant’s major features, including sensory details (color of flowers, presence of any unique fragrance, and tactile features such as sticky or spiny leaves).
I always collect three types of physical samples:
DNA specimen
A nickel sized amount of leaf material stored in a coin envelope and placed in a zip-lock bag filled with silica beads. These will be subjected to DNA analysis at a later date, pending grant funding.
Herbarium specimen
This includes leaf and fruits/flowers of the plant bent to fit into a folded sheet of newspaper. Duplicate specimens are always collected, with one specimen to be deposited in the home country, and one at Emory. Specimens are pressed flat and dried, and will later be affixed to archival paper for storage in the herbarium (a type of natural history museum).
Bulk specimen
A grocery-bag full of plant material, which needs to be processed by being chopped up and laid out to shade dry. After drying, samples are chopped up further in a food processor, then packed in a vacuum sealed back for shipment back to the Quave Lab under USDA import permit conditions. These will be ground into a fine powder in the lab, and then extracted for pharmacological and chemical testing, pending grant funding.
Upon arrival of all samples back in the lab, they will be put into a deep freezer for several days to kill any potential pests or plant pathogens that may have come along for the ride. This is critical to ensuring that we don’t put any US plants at risk to introduced pests. All samples are handled under quarantine conditions (my lab is certified as a USDA quarantine-compliant facility) and after we’re done pulling the chemistry out of the bulk samples of plant material, the remnant plant bits will be incinerated as a final biological safety security measure.
Herbarium specimens, on the other hand, will be carefully mounted to acid-free paper and digitized (capturing a high resolution image of the dried specimen along with all textual data). Digitization opens up access to these specimens for scientists, students, and the public across the globe! The Emory Herbarium deposits all plant digital specimens on the SERNEC portal. You can see some examples of my past collections here.
What’s Next?
Unfortunately, the pilot expedition is soon coming to a close. But, I still have much to share with you all about what I learned and will be sharing this in upcoming newsletter issues! In the meantime, take a look at some fun videos and images I shared using the Substack Notes feature. I think you’ll really enjoy these, especially the video explaining how a poisonous plant is used both as a fishing tool and a remedy for warts and calluses!
Yours in health, Dr. Quave
Cassandra L. Quave, Ph.D. is a Guggenheim Fellow, CNN Champion for Change, Fellow of the National Academy of Inventors, and award-winning author of The Plant Hunter. Her day job is as professor and herbarium curator at Emory University School of Medicine, where she leads a group of research scientists studying medicinal plants to find new life-saving drugs from nature. She hosts the Foodie Pharmacology podcast and writes the Nature’s Pharmacy newsletter to share the science behind natural medicines. To support her effort, consider a paid or founding subscription and tax-deductible donation to her lab research.
Such exciting work. I can’t wait to hear more!
So exciting!