Garden Pharmacy – Bitter leaf

My Burundi neighbour introduced me to bitter leaf. It’s a well-known, widely cultivated culinary and medicinal plant in Africa. She uses it for her diabetes, and when I started looking I found quite a lot of research supporting its folk medicine reputation for stabilizing blood sugar levels in type 2 diabetes. Given the life-threatening nature of diabetes, the idea of having some backup against price and supply chain issues is attractive.

There’s a good review of the research that supports its use for diabetes at https://biointerfaceresearch.com/wp-content/uploads/2021/10/20695837124.44964517.pdf. The research includes in vitro, animal and human studies, and concludes “The published literature used for the present work supports anti-diabetic properties of V. amygdalina”. In vitro, a water extract of bitter leaf was found to have significant effect on the key enzymes linked to type-2 diabetes. A 2018 study conducted on diabetic rats found that a combination of V. amygdalina Del and Gongronema latifolium (‘utazi’ ) had an effect comparable to that of insulin. There is also a study on rats that supports the idea that a combination of bitter leaf and metformin , a commonly prescribed pharmaceutical to control blood sugar, might be a good way to safely reduce the effective dose of metformin.

Doseage is of course important, but bitter leaf is widely used as a culinary herb and toxicity studies found it to be safe in the kind of quantities used in food. It is a very good source of polyphenols that are good for you in any case – berries, chocolate and green tea are some other foods rich in polyphenols – and the kind of plant flavonoids that have lots of health benefits..

In folk medicine, it’s also used as a worm treatment, a treatment for dysentry, constipation and stomach ache, a fertility drug, and as a treatment for malaria, but the evidence I found for those uses was a bit mixed, and it looks like there are better choices.

Vernonia amygdalina Del, Family Asteraceae (the daisy family, same as Chamomile), Bitter leaf

Bitter leaf is another tropical plant, native to the humid tropics of Nigeria, Cameroon and Zimbabawe. It’s a perennial small tree or woody shrub, that likes full sun, a warm humid climate, lots of compost and enough water. Given these conditions it can grow into a small tree. Ours, in sub-tropical northern NSW is a good four metres tall. But it can also be kept pruned to a woody shrub in a large pot, and given a warm spot in front of a sun-facing wall and regular watering it will do fine. In frosty climates it will need to be grown in a greenhouse or brought inside for winter.

It’s easiest and most commonly propagated from stem cuttings. We live in an area with a high African refugee population and it appears at the Farmer’s Market every so often. It can apparently also be propagated from seed but my Burundi neighbour tells me nobody propagates from seed in Africa if they can get cuttings.

There’s a good review that covers most of the medicinal use research I found at https://www.researchgate.net/publication/329807984_Vernonia_amygdalina_Del_A_Mini_Review

You will find the rest of this series by clicking the tag Medicinals.