Yuan Zhi (Polygala tenuifolia): Memory and Cognition

The concept of zhi (志), often translated as will, is integral to various aspects of Chinese philosophy and traditional medicine, including Daoism and the principles laid out in the Huangdi Neijing (黄帝内经), a foundational text of traditional Chinese medicine (TCM). The exploration of zhi within these contexts, especially in relation to the winter season, involves a deep and multifaceted understanding of Chinese thought.

In TCM, zhi is often associated with the kidney, which store a form of essential substance known as jing (精). This source is fundamental to life, growth, and development.

The kidneys, and by extension zhi, play a critical role in maintaining the body's balance and mind’s stability. In the context of seasons, winter is linked to the kidneys. The Neijing advises that during winter, one should conserve energy and reduce exertion to nurture the kidneys, aligning with the natural tendency for living beings to slow down and conserve resources during colder and darker months (1).

Daoism emphasizes living in harmony with the Dao (道), the fundamental principle that is the source of everything in the universe. In this context, zhi is often interpreted as the will or intent to align oneself with the natural flow of the Dao.

Practicing stillness, meditation, and inner reflection, especially during winter, is encouraged in Daoism. This aligns with the Neijing's guidance for winter, where the energy turns inward, and one's actions should mirror the quiescent nature of the season.

The Neijing suggests that winter is a time for conservation and reflection. It is a period to nourish the yin aspect of the body, characterized by stillness, coolness, and inward energy.

Both Daoist and Confucian concepts of zhi align with this seasonal guidance. Daoist practices of meditation and inner reflection during winter foster the conservation of energy, while Confucian emphasis on ethical will and self-cultivation resonates with the introspective nature of the season.

Yuan Zhi (遠志), literally translating to “Vast Will”, known botanically as Polygala tenuifolia, has been a cornerstone in Traditional Chinese Medicine (TCM) for centuries, primarily used for its mental health benefits. This review provides a general overview of its historical significance, pharmacological properties, and contemporary relevance, with a particular focus on its application in supporting memory, as explored in classical and modern literature.

Historically, Yuan Zhi has been valued for settling the heart and opening its orifice, dispersing phlegm, and reconnecting communication between heart and kidney. It's been used in formulations for treating insomnia, palpitations, and forgetfulness, such as:

1. Rescue the Spirit (An Shen Ding Zhi Wan/Kan Traditionals)

2. Celestial Emperor’s Blend (Tian Wang Bu Xin Dan/Kan Traditionals)

3. Gather Vitality (Gui Pi Tang/Kan Herbals)

4. Quiet Calm (Gentle Warriors)

5. Peaceful Shen (Wen Dan Tang/Kan Traditionals)

6. Compassionate Sage (Hu Po Yang Xin Dan/Kan Herbals)

Yuan Zhi’s significance is also noted in Kampo (Japanese adaptation of Chinese medicine) and Korean traditional medicine, emphasizing its role in mental and emotional health. Li Shizhen's Bencao Gangmu offers a detailed description of Yuan Zhi, classifying it as a substance that can expel phlegm, clear orifices, and tranquilize the mind (2).

Another important function of Yuan Zhi is to resolve phlegm in the Lungs and chest (3).

1. Augmented Plum Pit Qi (Ban Xia Hou Po Tang/Kan Traditionals)

2. Chest Relief (Gentle Warriors)

Yuan Zhi's historical significance, documented benefits across various Asian medical systems, and ongoing scientific research paint a picture of an herb deeply rooted in traditional practices yet adaptable to modern therapeutic needs. Its role in memory disorders, particularly in the elderly, demonstrates its enduring relevance in holistic health approaches.

Mechanism-Of-Action

In Traditional Chinese Medicine (TCM), the concept of opening the orifices represents a therapeutic principle aimed at removing obstructions in the heart’s ability to integrate sensory information, to restore mental clarity and cognitive function. This approach is based on the understanding that mental disturbances are often linked to blockages resulting from qi and blood stagnation, qi deficiency, phlegm, and cold. Polygala root (Yuan Zhi) is recognized in this context as an agent capable of clearing these obstructions, thereby enhancing mental and emotional well-being.

The early text Shennong Bencao Jing highlights the importance of Yuan Zhi, underscoring its role in clearing the mind and harmonizing the spirit, a view that aligns with subsequent texts such as the Shang Han Za Bing Lun and Bencao Gangmu (4).

Eastland Herb Materia Medica notes that Yuan Zhi is contraindicated “...for those with yin deficiency with heat signs as well as those with peptic ulcers or gastritis,” (5). When processed with gan cao (licorice), this contraindication is moderated. Yuan Zhi is a common constituent of formulas which tonify the yin, such as Tian Wang Bu Xin Dan.

Yuan Zhi has been used in TCM for centuries, primarily for its benefits in improving cognitive function, alleviating insomnia, and calming the mind. The scientific exploration of its mechanism-of-action (MOA), however, is an ongoing area of research. Here are some key aspects of the current understanding:

Yuan Zhi contains compounds like tenuifolin, polygalasaponins, and oligosaccharide esters, which have been studied for their potential neuroprotective effects. These compounds may help in improving memory and cognitive functions, by possibly modulating neurotransmitter systems, enhancing neurogenesis, and providing neuroprotection.

Research has suggested that Yuan Zhi may influence several neurotransmitter systems, including acetylcholine, which plays a critical role in memory and learning. It may also impact the dopaminergic and serotonergic systems, which are involved in mood regulation and cognitive processes.

The root extract of Yuan Zhi has demonstrated anti-inflammatory and antioxidant properties in various studies. These effects can contribute to its neuroprotective actions, as oxidative stress and inflammation are implicated in the pathogenesis of many neurodegenerative diseases.

Compounds in Yuan Zhi are believed to influence sleep mechanisms, potentially explaining its traditional use in treating insomnia. This effect might be mediated through GABAergic systems, which are known to play a role in sleep regulation.

It's important to note that while these findings provide insight into the possible mechanism-of-action of Yuan Zhi, much of the research is preliminary and conducted in vitro (in test tubes) or in vivo (in animal models). Clinical trials in humans are necessary to fully understand its efficacy, from a more broad physiological perspective (6,7).

Furthermore, the complexity of herbal medicine, with its multitude of active components, makes it challenging to isolate the specific mechanisms of action of any one compound.

Yuan Zhi's enduring significance in TCM, documented across various Asian medical systems and supported by ongoing scientific research, demonstrates its adaptability to modern therapeutic needs, particularly in formulas like Quiet Calm, An Shen Ding Zhi Wan, and Tian Wang Bu Xin Dan, for holistic health approaches.

Ding Zhi Wan: An Overview

Ding Zhi Wan, a classical TCM formula, has long been used to address specific mental and emotional imbalances. Translated as "Settle the Emotions Pill," this formula originates from Beiji qianjin yaofang (備急千金要方), Essential Formulas Worth a Thousand in Gold for Emergencies (8), a 7th century medical text by Sun Simiao from the Tang dynasty. It includes several key ingredients:

• Ren Shen (Ginseng Root): Boosts Qi and mental function.

• Fu Ling (Poria): Enhances mental clarity and quiets the heart.

• Shi Chang Pu (Acorus Rhizome): Clears phlegm and alleviates mental confusion.

• Yuan Zhi (Polygala Root): Calms the spirit and harmonizes the heart and kidney.

Ding Zhi Wan is typically prescribed for heart qi deficiency with constraint by phlegm, manifesting as anxiety, restlessness, concentration difficulties, and mild palpitations. The formulation can be tailored to the individual's constitution and symptoms, based on TCM diagnostics.

Ding Zhi Wan's principles remain relevant in modern TCM, particularly in holistic and integrative mental health approaches. However, its integration into conventional treatments requires further scientific validation.

Kan Herb Company features over 23 formulas which utilize Yuan Zhi. Let’s dig into a handful, with an overview of the actions, indications, and makeup.

Exemplar Formulas Containing Yuan Zhi

Rescue the Spirit expands on An Shen Ding Zhi Wan, focusing on transforming Phlegm, tonifying Blood and Yin, and regulating Qi. Polygala (Yuan Zhi) plays an essential role in connecting heart and kidney, and resolving phlegm-obstruction.

Additional ingredients include Dry Fried Sour Jujube Seed (Suan Zao Ren), Polygonum Multiflorum Stem (Ye Jiao Teng), Biota Seed (Bai Zi Ren), Schisandra Fruit (Wu Wei Zi), Red Jujube Fruit (Hong Zao), White Peony Root (Bai Shao), Ophiopogon Tuber (Mai Men Dong), and Turmeric Root Tuber (Yu Jin). This formula aims to address spirit disturbances resulting from intrinsic deficiencies or external factors. By adding the Kan Single Chinese Red Ginseng Root to this formula, a sophisticated, yin-tonifying version of the classic Ding Zhi Wan can be achieved.

Quiet Calm: A Holistic Approach for Children

Quiet Calm is a TCM formulation for children, designed to clear Heat and Phlegm, nurture the brain and marrow, and balance Kidney, Liver, and Heart functions. Here, Yuan Zhi guides the therapeutic action to the shaoyin layer, resolving phlegm, and settling the shen.

The formula includes components of Wild Jujube Seed Decoction (Suan Zao Ren Tang), Gastrodia and Uncaria Decoction (Tian Ma Gou Teng Yin), with additional ingredients like Lily bulb (Bai He) and Red tangerine peel (Ju Hong), supporting the mental and emotional health of children, and addressing symptoms like tantrums and agitation.

Celestial Emperor’s Blend

The Celestial Emperor’s Blend, inspired by the classical Tian Wang Bu Xin Wan, offers a holistic approach to treating Heart and Kidney imbalances in Traditional Chinese Medicine. Yuan Zhi is absolutely necessary in this formula, as it has the specific and direct function of harmonizing heart and kidney.

This formula addresses issues of deficiency by enriching Yin, nourishing Blood, calming the Spirit, and clearing Heat. Along with Yuan Zhi, ingredients like Raw Rehmannia root (Sheng Di Huang) and Chinese asparagus tuber (Tian Dong) work to harmonize the Kidney-Heart relationship and cool the Heart, while others like Chinese salvia root (Dan Shen) and Dong quai root (Dang Gui) tonify Blood and Qi.

Especially beneficial for aging individuals and those with mental and emotional disturbances linked to Heart and Kidney imbalances, this formula can be combined with others like Temper Fire (Zhi Bai Di Huang Wan) or Shen Ling Spleen Support (Shen Ling Bai Zhu San) for enhanced effects.

Augmented Plum Pit Qi

The Augmented Plum Pit Qi formula, an evolution of the classical Pinellia and Magnolia Bark Decoction, targets Qi stagnation and Phlegm, especially in the Liver, Lungs, and Stomach. This formula effectively addresses the sensation of a "plum pit" in the throat by harmonizing the Stomach and transforming Phlegm with ingredients like licorice cured Pinellia rhizome (Fa Ban Xia), Magnolia bark (Hou Po), and Polygala (Yuan Zhi).

Additional herbs such as Bupleurum root (Chai Hu) and Turmeric root tuber (Yu Jin) enhance this formula’s capacity to move stagnant Qi and clear Phlegm. Augmented Plum Pit Qi is part of the Kan Herbals line, addressing various Phlegm patterns, and is a modern adaptation of a formula with roots in the Han Dynasty's Essentials from the Golden Cabinet.

Chest Relief (Gentle Warriors)

Geared especially for children, this formula aims to transform and dispel Phlegm, moisturize dryness, and support respiratory function. Key herbs include Bamboo secretion (Tian Zhu Huang), Polygala root (Yuan Zhi), and Trichosanthes seed (Gua Lou Ren) for Phlegm and dryness, along with others like Licorice cured Pinellia rhizome (Fa Ban Xia) and Magnolia bark (Hou Po) to redirect Qi and settle the Stomach.

Chest Relief also focuses on balancing cooling and warming properties, with herbs like Ginger rhizome (Gan Jiang) to prevent overcooling, essential for the harmonious flow of Qi and maintaining respiratory health.

A Return to Yuan Zhi 遠志 - Vast Will

As can be seen from this topical survey, Yuan Zhi is a profound agent, weaving itself through myriad formulas with its versatile array of actions. For calming the mind, transforming phlegm-obstruction, and restoring the suffusion of Heart Fire and Kidney Water, Yuan Zhi can be relied upon for its elegant influence.