Gingko’s Synergy with Prescribed Medication

Article by Ann Walker

Ginkgo (Ginkgo biloba) trees are sometimes called living fossils – they have thrived on Earth with little genetic change since the time of the dinosaurs, around 200 million years ago. They are tough and resilient trees which survived fallout from the asteroid that extinguished the dinosaurs and from the atomic bomb dropped on Hiroshima in 1945. In China the nuts were used for millennia as medicine for lung complaints, but it is the extracts of the leaves that were developed as medicine in Germany from the 1960s. Ginkgo is the most researched herbal medicine in the world, with attention focused in particular for its benefits as treatment for dementia, memory loss and pain caused by too little blood flow (claudication).

So, it’s good to see increasing evidence coming forward of positive herb-drug interactions (or synergy). This past twelve months, we have seen two examples of synergy in ginkgo studies. The first was a combination of ginkgo with steroids (PMID: 29797955). The forty-two volunteers in the study had lost their sense of smell due to nasal congestion following a viral infection. All received daily steroids, but half of them also took ginkgo extract daily for 3 months. While the sense of smell was improved in all patients, it was improved to a greater extent in the combination group.

The second study was larger, with 136 elderly people with depression (PMID: 30278520). All took the antidepressant citalopram daily but half of them took, in addition, a daily supplement of ginkgo. The combined treatment alleviated depression faster that citalopram alone. Furthermore, the lowering of depression was accompanied by a drop in S100B protein in the bloodstream. S110B is released by ‘housekeeping’ cells in the brain in response to injury and levels are high in depression. In this study, the drop in S100B levels in the combined group was greater than in the citalopram-alone group.

Practitioners of herbal medicine always check the drugs their patients are using/prescribed, to avoid potential herb-drug interactions. Fortunately, proven negative interactions between herbs and drugs in humans are rare, but, even so, the media frequently carries scare stories of adverse interactions based on speculative, rather than proven cases. Often adverse herb-drug interactions cited in the press are based on extrapolated data from laboratory animals fed high levels of the herb, or test-tube studies or just plain guesses. So, it is good to see research reports of positive interactions (synergy) between herbs and drugs.

PMID = PubMed identifier

Ann Walker PhD FCPP MNIMH RNutr
Course Director DHM
Herbal Practitioner

Passiflora Reduces Stress of Tooth Extraction

Article by Ann Walker

This is a picture of Passiflora incarnata (also called pasque flower or passion flower), which I took some years ago in one of the National parks in Florida, where it grows abundantly in the wild. The first European settlers to North America were introduced to the use of the leaves of this plant by the Native American people and the herb remains until this day an important, effective and non-addictive sedative to reduce symptoms of anxiety or nervousness.

Laboratory studies on the plant are numerous and support these traditional uses and mechanistic studies have pointed to the action of this herb operating through modulation of the GABA (gamma-amino butyric acid) neurotransmitter system in the brain, but the jury is still out. Although the compounds present in passiflora have been identified, no single compound has yet been found to account for its physiological action. Hence, it is likely that two or more compounds work in synergy, as we have found to be the case for several other herbs.

Small-scale clinical studies have, in the past, supported the use of passiflora for anxiety, but now a Brazilian study (PMID: 27918731) has compared the anxiety levels of volunteers taking a single dose of either passiflora (260 mg of extract) or a benzodiazepine drug called midazolam (15 mg) before wisdom tooth extraction. The study was randomised, double-blind and cross-over in design. Each of forty volunteers had two extractions – one tooth on one side of the jaw with a dose of passiflora given beforehand and, on a separate occasion, a tooth on the other side of the jaw, with the drug given beforehand. [A cross-over design using two interventions on the same volunteer like this is regarded as superior to using only one intervention per person, because the volunteer acts as their own control, giving more strength to the study.]

Over 70% of the volunteers said that they felt calm or only a little anxious under both protocols – indicating that the effect of passiflora was equivalent to the drug. However, whilst using passiflora there was no significant interference with memory, whilst 20% of volunteers reported no recollection at all whilst on the drug.

While more rigorous clinical trials to assess the traditional use of passiflora would be very welcome, the herb remains an effective non-addictive sedative that does not cause drowsiness. Fortunately, quality extracts of passiflora are freely available in herbal products which carry a THR (Traditional Herbal Registration) and further information on these THR products containing passiflora can be found on the BHMA website to ensure safety of use.

PMID = PubMed identifier

Ann Walker PhD FCPP MNIMH RNutr
Course Director DHM
Herbal Practitioner

Synergy of Baical Skullcap and Antibiotics for MRSA

Article and photo by Ann Walker

The term methicillin-resistant Staphylococcus aureus (MRSA) refers to a group of bacteria that are genetically distinct from other strains of S. aureus – a common bacteria found normally on human skin or nasal passages. The MRSA strains are resistant to most common antibiotics and are often associated with hospital infections which are very difficult-to-treat.

The root of Scutellaria baicalensis, also called Chinese skullcap or Baical skullcap, has long been used in traditional Chinese herbal medicine. The herb is often found in herbal formulas designed to alleviate inflammatory symptoms including allergies, auto-immune disorders and bacterial infections. Impressed with its wide applications, many western herbal practitioners, like myself, have included it in their own materia medica. It is the flavonoids, baicalin, wogonin and baicalein, in Baical skullcap which are of most interest: these compounds have clear anti-inflammatory and anti-allergic activity in laboratory studies. But what has caused some excitement among researchers over recent years is the finding, first hinted at 18 years ago, that these flavonoids can act in synergy with antibiotics to enhance their activity against MRSA (PMID: 10757427), by reversing the mechanisms leading to resistance.

Baical skullcap and its flavonoids have good bactericidal properties in their own right, including, notably, against H. pylori, the bacteria which cause stomach ulcers and upper digestive discomfort (PMID: 18826148). But, more recently, the ‘synergy’ story of the herb, taken along with antibiotics has been followed up. There is now evidence that baicalein can reverse both penicillin resistance (PMID: 26028441) and ciprofloxacin resistance (PMID: 21782012) of MRSA in test-tube studies. News that an ancient remedy may be profitably used as an adjunct to modern antibiotics to enhance their effect or even reverse resistance is encouraging for future healthcare.

PMID = PubMed identifier

Ann Walker PhD FCPP MNIMH RNutr
Course Director DHM
Herbal Practitioner

Therapeutic Potential of Ivy Leaf (Hedera helix)

Article & Photo by Ann Walker

I took this photo a few days ago near the River Thames at Wallingford on a lovely autumn day. Ivy (Hedera helix) is one of the few plants in bloom at this time of the year and some species of bees are totally dependent on it for their winter supplies of honey. Ivy is a tough plant in the same family as ginseng (Panax ginseng), so herbal connections should not be unexpected.

However, I was surprised to find earlier this year that at least two herbal supplement products containing ivy have been granted THR (Traditional Herbal Registration) status by the MHRA (Medicines & Healthcare products Regulatory Agency, UK), yet ivy is not a herb much used by herbal practitioners in Britain. (A list of herbal products granted a THR can be found on the MHRA website by entering “List of products granted a Traditional Herbal Registration” in the search box.)

As the criteria for obtaining a THR is very strict and these ivy products are now available freely for sale to the public, I thought it would be worthwhile to include a monograph on ivy for our updated version of the Discovering Herbal Medicine course.

Ivy leaf has a long-documented history of use, particularly in continental Europe, for its ability to loosen sticky phlegm in the airways. The herb contains an impressive number of active compounds and, in particular, saponins – a group of compounds related to those found in ginseng. These ivy compounds show physiological and anti-microbial actions in test-tube and animal studies, which support the ivy’s traditional use for respiratory-tract infections. Although clinical trial data is scarce, three randomized clinical studies carried out in Germany show positive effects on respiratory health of the consumption of ivy extracts for adults and children (PMID: 22532491; 24916707; 29441845).

Ivy leaf preparations are safe taken in recommended (small) doses combined with other herbs and as such are well tolerated. Syrups, drops, tablets, suppositories and liquids containing ivy leaf extracts often combined with thyme (Thymus vulgaris) (see PMID: 17063641) are now available throughout the EU for symptoms of coughing, especially following bacterial infections. Potentially, the herb holds promise for treating conditions wider than just the respiratory tract, but more research is needed. Ivy leaf is clearly a herb with therapeutic potential and herbal practitioners in the UK might consider including it in their own materia medica.

PMID = PubMed identifier

Ann Walker PhD FCPP MNIMH RNutr
Course Director DHM
Herbal Practitioner