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Diane Robertson Winn: 1937-2020


Diane Robertson Winn, a medical researcher, entrepreneur, and artist who is known for her work with the African antimalarial plant cryptolepis (Cryptolepis sanguinolenta, Apocynaceae), died from congestive heart failure on April 21, 2020, at age 82. For about 50 years, she traveled between the United States and Ghana in West Africa to produce and market effective, affordable treatments for malaria and other conditions, befriending African leaders and villagers in the process.

Winn was born on November 19, 1937, and raised in Allentown, Pennsylvania. In 1959, she earned a bachelor’s degree in biology from Cedar Crest College in Allentown and then earned a master’s degree in medical illustration from Johns Hopkins University in Baltimore, Maryland.

In 1962, Winn was researching cancer at the US National Institutes of Health (NIH) in Bethesda, Maryland, when she agreed to be part of a 20-person team of scientists to conduct research in Ghana, without even knowing where the country was. She was 25 at the time. US President John F. Kennedy sent the research team at the request of Ghanaian President Kwame Nkrumah. The previous year, Kennedy sent Peace Corps volunteers to Ghana on that program’s first assignment.

“When I first arrived, I felt at home immediately,” Winn was quoted as saying in a 2010 article published in The Baltimore Sun.1 “The people of Ghana are so outgoing and so friendly. [That] was the first time in my life that I felt comfortable in my own skin.”

Soon after arriving in Ghana, Winn met Oku Ampofo, MD, who would significantly impact her life. A native Ghanaian who received medical training in Edinburgh, Scotland, Ampofo was dedicated to incorporating native Ghanaian plants into the treatment of illnesses. Ampofo, also a trained sculptor, used sculpting to fund his medical practice and research, because many of his patients could not pay. In fact, some of his sculptures decorated Winn’s condo in her later years.

Winn and Ampofo bonded through their shared love of art. Winn was also a talented artist and loved creating portraits of people she met using oil-based pastels. She depicted the Ashanti king in Ghana and several presidents of Ghana and their wives and also spoke to them about medical matters.

In addition to art, Winn and Ampofo connected through medicine. She provided equipment for his laboratories at the Centre for Scientific Research into Plant Medicine, which was established in 1975 in his hometown of Mampong-Akwapim and later became a World Health Organization collaborating center. Through Winn, Ampofo met cancer researchers in the United States and regularly provided plants for them to screen.

Ampofo showed respect for traditional herbalists, who, as a result, taught him about the plants. “It was phenomenal that [the herbalists] were willing to share their knowledge with him, since they usually only pass their secrets on to one of their children,” Winn was quoted as saying.1 Winn claimed that, at one time, Ampofo used herbal medicine to cure her of breast cancer, and when he became frail and blind later in life, she reportedly brought him to the United States to be treated at Johns Hopkins. Before Ampofo died in 1998 at age 90, he shared his knowledge with Winn and asked her to make some of his best plant medicines commercially available.

Winn followed through on Ampofo’s request. In 2000, Phyto-Riker Pharmaceuticals in Accra, Ghana, a company Winn co-founded, began selling Phyto-Laria®, a tea bag product made from the roots of cryptolepis. Ampofo had used cryptolepis for the treatment of drug-resistant falciparum malaria. This thin-stemmed shrub is also called nibima, among other names, and its roots have been used in traditional African medicine to treat various diseases, including malaria. Unlike most other plant-derived malaria treatments on the market, the tea is a true herbal remedy containing a mixture of phytochemicals.

Winn’s product was shown to be safe and effective in a study published in the Ghana Medical Journal. In this study, 44 people with uncomplicated malaria were given three doses of Phyto-Laria tea per day for five days. More than half of the participants were cleared of malaria parasites within 72 hours, and the mean fever clearance time was 25.2 hours. Other malaria symptoms, including chills, vomiting, and nausea, were cleared completely in 72 hours. The cure rate in this study was 93.5%.2

However, despite its apparent safety and efficacy, Phyto-Laria eventually went off the market. That may be at least partly because its acrid taste prevented some people from completing an entire course, which can cause relapse. “The tea bags were an easy way to administer the [treatment], and its bitterness was not something we thought would matter,” Winn was quoted as saying.1

In 2010, Phytica, a second company Winn co-founded in 2006, which received funding from the government of Ghana, was trying to solve the tolerability problem by creating an equally effective capsule form of the treatment called Larax. It was hoped that Larax would undergo clinical trials, be approved, and become available by the end of 2010. It was also hoped that the product would create the need for Ghanaians to grow cryptolepis and assist in other aspects of production, which would benefit the country’s economy.1 However, it does not appear that Larax came to market as planned.

Bruce Brown, president of New Jersey-based Ayurvedic phytomedicine manufacturer Natreon, remembers Winn fondly. Brown previously served as chief operating officer and director of public health projects at Phyto-Riker Pharmaceuticals. “Diane was a thoughtful entrepreneur who focused on several core principles in each endeavor she undertook and formulated an ethical approach to business,” Brown wrote (email, July 17, 2020). “Diane sought first to support the development of traditional medicine with modern science and manufacturing. And, she did so in complete alignment with the communities from which traditional herbal medical knowledge and practices were developed.

“Her greatest strength was creating collaboration between cultures, encouraging teamwork and respect regardless of race or background or country of origin, and bringing passion and commitment to every project she touched,” Brown added. “I am glad to have had the opportunity to collaborate with her professionally, travel with her extensively in the land she loved, Ghana, and invite her into my home as a friend.”

Though she lived in Ghana for only four years, from 1962 to 1966, Winn traveled there more than 100 times in her lifetime. Even in her late 70s, she still conducted business from her senior living community in Catonsville, Maryland.3 Winn emphasized the need to improve global health while employing Africans in farming, production, and management. Her company Phytica also worked on treatments for asthma and malnutrition.

During her life, Winn helped establish multiple companies, including the International Sickle Cell Anemia Research Institute; MediVisuals, which makes medical visuals for legal testimonies; Phyto-Riker Pharmaceuticals; and Phytica. She also created a database including more than 270 plants that have been used to treat more than 100 conditions. Winn contributed to multiple issues of HerbalGram, including co-authoring a profile of Ampofo in issue 31 (1994),4 authoring a tribute to him in issue 43 (1998),5 and providing photos for a review of cryptolepis in issue 60 (2003).6

Winn loved being a grandmother and singing in her church choir. Through her church, she helped raise funds for the Baptist School Complex and Orphanage near Koforidua, Ghana. Her true love was Robert Daniel (Dan) Winn of Dallas, Texas, a patent attorney and entrepreneur who was passionate about medicinal plant research and reforestation and ardently supported Diane’s work. They were married from 1994 until he died in 2006 from an accident in Nairobi, Kenya, where he and Diane were attending a conference on antimalarials.7 Diane Robertson Winn is survived by her three children, Bruce (Kathy) Robertson, Alice (Ed) Rumsey, and Gibbs (Tara) Murayama; her six grandchildren; her brother David (Pat) Diehl and his family; and many friends in the United States and Ghana.


  1. Holzberg J. A Taste of Success. The Baltimore Sun. January 10, 2010. Available at: Accessed July 3, 2020.
  2. Bugyei KA, Boye GL, Addy ME. Clinical efficacy of a tea-bag formulation of Cryptolepis Sanguinolenta root in the treatment of acute uncomplicated falciparum malaria. Ghana Med J. 2010 Mar;44(1):3-9. doi: 10.4314/gmj.v44i1.68849.
  3. Norris H. Fighting malaria in Africa from apartment in Charlestown. The Baltimore Sun. November 17, 2015. Available at: Accessed July 3, 2020.
  4. Girardet H, Robertson Winn D. Profile of a Traditional Healer: Oku Ampofo. HerbalGram. 1994;31:46. Available at: Accessed July 15, 2020.
  5. Robertson Winn D. In Memoriam: Oku Ampofo 1908-1998. HerbalGram. 1998;43:62. Available at: Accessed July 15, 2020.
  6. Addy M. Cryptolepis: An African Traditional Medicine that Provides Hope for Malaria Victims. HerbalGram. 2003;60:54-59,67. Available at: Accessed July 15, 2020.
  7. Robert Daniel Winn: 1927-2006. HerbalGram. 2006;72:76-77. Available at: Accessed July 15, 2020.