Three Cheers for Periwinkle: Ethnobotany, histiocytosis and Rare Disease Day

Just over seven years ago, my youngest son, then eighteen months old, woke up one morning with a lump exactly the size and shape of an olive behind his ear. An X-ray revealed a quarter-sized hole in his skull and a mass of dense tissue. The initial diagnosis -- malignant tumor of the cranium -- left everyone in the family reeling, incredulous and praying for a miracle. Within a few days and thanks to the incredible staff at the Boldrini Children's Hospital in Campinas, Brazil (if I ever become a millionaire I will leave my fortune to them), this diagnosis was rejected in lieu of something far stranger: Langerhans cell histiocytosis, also known as eosinophilic granuloma or histiocytosis-X (due its mysterious etiology), a childhood disease that is a hundred times rarer than leukemia and thus often misdiagnosed.

You know you are desperate when a doctor tells you your child has an extremely rare immune system condition of unknown origin that punches Swiss-cheese-like holes in the bones and especially the skull, fatal in about 15% of the cases and usually treated through experimental drug protocols, and you feel relieved.

Periwinkle: Our little miracle

His initial treatment included small doses of vinblastine, a drug derived from the caustic sap of the rosy periwinkle, Catharanthus roseus (or Vinca rosea), native to Madagascar. In a matter of days, the olive-sized lump looked more like a caper, and within six weeks the tumor was no longer visible to the eye. The treatment regime continued for another two years with a cocktail of drugs similar to those used for leukemia but in far smaller doses. 

I am very relieved to say that he is now fully recovered and suffered no side-effects from more than two years of low-dose chemotherapy. Miracles really do happen.

I owe this particular miracle at least in part to the wonders of traditional medicine and the rigors of ethnobotanical investigation. Vinblastine and other cancer-treating vinca alkaloids were discovered in the late 1950s by Canadian physician Robert L. Noble, whose brother Clark Noble, involved in the discovery of insulin, forwarded him a packet of medicinal leaves sent by a patient who had visited Jamaica and heard the plant was used there to treat diabetes. While the plant extract had little effect on glucose levels, it produced a powerful response in white blood counts and quickly became a mainstay in the treatment of many kinds of cancer.

The Madagascar or rosy periwinkle (photo: Wikipedia)

Despite the widely trumpeted promise of discovering novel cures with rainforest shamans -- remember that Sean Connery film, "Medicine Man"? -- research on medicinal plants in most Latin American countries has slowed to a standstill, though India and China race ahead. On the one hand, exaggerated concerns about "biopiracy" (some call it "bioparanoia") have scared many governments, particularly Brazil, into bureaucratizing and restricting bioprospecting to virtual paralysis, dampening once hopeful aspirations for economic development based on traditional knowledge and biodiversity.[1] On the other hand, technological advances have led drug companies to focus more on computer-based molecular modeling and gene therapy, and less on old-school natural products research. Finally, many traditional medicines address diseases of the poor, and so are of little interest to the profit-driven pharmaceutical industry.

I have often been impressed by the efficacy of native remedies.

During my own ethnobotanical work in Peru I used native Matsigenka remedies on myself to cure a medically diagnosed case of cutaneous leishmaniasis, the South American skin disease related to the dreaded, visceral Old World form of leishmaniasis known as kala-azar. However I stopped researching medicinal plants after moving to Brazil to avoid bureaucratic headaches and out of fear of biopiracy accusations.

Despite technological changes and a sometimes hostile research environment, new and important drugs are still being discovered through ethnobotanical investigation. An extract of Sangre de drago ("dragon's blood"), a tree sap used medicinally in the Amazon, was recently approved by the United States Food and Drug Administration for treating AIDS symptoms. Artemesin, now a last-ditch therapy for drug-resistant malaria, is likewise derived from a Chinese medicinal plant related to wormwood.

And so in recognition of International Rare Disease Day (February 28) and the Histiocytosis Association's campaign to improve diagnosis and treatment, I call attention to this rare childhood disease and to the role of traditional medicine and ethnobotany in its treatment. I also pause to give thanks for my own little (big) miracle. 

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References: 

[1] Frickman, F. S. S. & A. G. Vasconcellos. (2010). Oportunidades para inovação e aproveitamento da biodiversidade amazônica em bases sustentaveis. T&C Amazônia 8(19): 20-28.