Herb of the Month

Ginkgo (Ginkgo biloba)

Marianne Hughes, with illustration by Hazel Brady

As the fan-shaped leaves turn to a bright, buttery yellow, the Ginkgo biloba heralds the arrival of Autumn. This tree has inhabited our Earth for at least 200 million years. After the devasting atomic bombs were dropped on Hiroshima and Nagasaki, Ginkgo was one of the only trees to produce new shoots from charred tree stumps. This demonstration of resilience can bring hope— and both resilience and hope are qualities which we have needed for many months, and continue to need. Perhaps standing near a Ginkgo tree this Autumn, contemplating its remarkable survival, can be a tonic for all of us.

As Siewert (2016) observes: 'Ginkgo leads us to our centre and to our life force. It supports us in the process of accepting ourselves and our surroundings in regard to light and darkness. Ginkgo takes us by the hand and helps us to connect what belongs together.' For many years, Ginkgo has been a symbol in China for a long and healthy life. Chinese monks chew the leaves of Ginkgo, believing that it aids their mental agility. Indeed, the Ginkgo leaf does significantly improve and tonify circulation, and especially cerebral circulation. It inhibits platelet activation factor— which tends to make the blood thick and sticky, and which contributes to atherosclerosis (Ody, 1993) —so Ginkgo can increase the effect of anticoagulant drugs. Synthesising a range of recent research, Ahmad et al (2019) note that the pharmacologically active constituents of Ginkgo are flavonoids and terpenoids, and that the therapeutic mechanisms of Ginkgo are its antioxidant effects, inhibition of beta amyloidal peptide, and modulation of different cell signalling receptors and factors. Of relevance to the current pandemic, Buhner (2013) describes in great detail the mechanisms by which coronaviruses impact on the human body by attaching to angiotensin converting enzyme 2 (ACE-2), which is an integral membrane protein on many cells throughout the body including in the heart, lungs, lymph, spleen, vascular cells and kidneys. Once the receptors on these cells are compromised, enhanced vascular permeability leads to worsening function. Ginkgo and other herbs can protect ACE-2 expression and activity.

It is probably the impact that Ginkgo can have on memory that the layperson is most familiar with, and so it is worth considering whether this impact is backed up by scientific research. There are around 50 million people worldwide with Alzheimer’s disease (AD), and many more with other types of dementia. Liu et al (2020) reviewed all of the studies relating to AD since the 1980s and concluded that 'Ginkgo biloba L. leaf extract (EGb) may be able to improve the cognitive function in patients who suffered from mild dementia during long-term administration (more than 24 weeks) and appropriate dosage (240mg per day).' So this is a positive message for people in the early stages of Alzheimer’s disease.

Today, Ginkgo can assist not only our own resilience but also that of our environment. Ginkgo is remarkable for being able to tolerate the urban pollution of our cities (Stobart, 2020). In so doing, it provides beauty to our streets and to our hearts.

References: Ahmad, I., Chattopadhyah, D. & Khan, M. S. A., eds. (2019) New Look to Phytomedicine: Advancements in Herbal Products as Novel Drug Leads. Academic Press: Cambridge, MA Buhner, S. H. (2013) Herbal Antivirals: Natural Remedies for Emerging & Resistant Viral Infections. Storey Publishing: North Adams Liu, H., Ye, M., & Guo, H. (2020) ‘An Updated Review of Randomized Clinical Trials Testing the Improvement of Cognitive Function of Ginkgo Biloba Extract in Healthy People and Alzheimer’s Patients’ in Frontiers in Pharmacology, 10, 1688 Ody, P. (1993) The Complete Medicinal Herbal: A Practical Guide to the Healing Properties of Herbs. Skyhorse Publishing: New York Siewert, A. M. (2016) Natural Antibiotics & Botanical Treatments: Heal Your Body, Heal Your Mind. Robert Rose Inc: Ontario Stobart, A. (2020) The Medicinal Forest Garden Handbook: Growing, Harvesting and Using Healing Trees and Shrubs in a Temperate Climate. Permanent Publications: East Meon