Herbal Constituents: An Introductory Guide

What are Herbal Constituents?

By the Seed SistAs

Over the past three billion years, our beloved plants have evolved sophisticated biochemical systems to survive in an ever-changing environment. In doing so, they’ve become nature’s most brilliant chemists—producing compounds not only essential for their own survival but also luckily for us beneficial to health too.

These compounds, known as herbal constituents or phytochemicals, are what are termed the ‘active ingredients’ in medicinal plants. When consumed, they can have measurable effects on the human body—supporting healing, alleviating pain and suffering, altering physiology, altering consciousness or sometimes causing harm in the form of toxicity if misused.

Herbal constituents can be grouped by their chemical structure. Some, like flavonoids, are widespread across the plant kingdom. Others, like curcumin, are unique to specific species.

When making your medicines the method you use to extract these constituents—water, alcohol, oil, or vinegar—can significantly affect their availability and potency.

Some herbal compounds can cross the blood-brain barrier, affecting the nervous system. Others act more peripherally, influencing the immune system, liver, or cardiovascular system.

How Well Do You Know Your Herbs?

• What chemical compounds make plants healing—or potentially harmful?
• Can you choose the right preparation method to get the desired effect?
• What’s the real difference between a tea and a tincture, chemically speaking?

If you’ve ever wondered why some herbs shine as teas while others are more powerful as tinctures and some others are best as oils, understanding herbal constituents is the key. It unlocks not only more effective remedies and more effective herbalism.

Plants as Chemical Factories

Plants are, in essence, highly efficient biochemical factories. In response to stressors, like pests, pathogens, and UV exposure, they’ve developed a vast range of chemical defences. Many of these phytochemicals happen to be deeply therapeutic to humans.

Types of Plant Compounds:

1. Primary metabolites – Involved in the plant’s growth and survival (e.g., carbohydrates, amino acids).
2. Secondary metabolites – Enable the plant to adapt and defend itself. These are often the compounds of greatest interest to herbalists.

These secondary metabolites include:

• Alkaloids
• Flavonoids
• Terpenoids
• Polyphenols
• Glycosides

Major Classes of Herbal Constituents Table 

Different herbal compounds dissolve best in different solvents, so understanding which preparation method extracts which constituents is key to making safe and effective remedies. Water-based preparations like teas, infusions, and decoctions extract water-soluble compounds such as polysaccharides (like mucilage), minerals, tannins, and flavonoids. Alcohol-based preparations (tinctures) extract a wide range, including alkaloids, volatile oils, and resins—especially with high-proof alcohol. Oil-based preparations, such as infused oils and salves, are best for drawing out lipid-soluble compounds. Vinegar-based preparations, like herbal vinegars and oxymels, use mildly acidic, water-based solvents to efficiently extract minerals, some alkaloids, and aromatics.

Synergy and the Whole Plant Philosophy

One of herbalism’s core principles is synergy—the idea that a whole plant is more than the sum of its parts.

Why the Whole Plant Matters

Whole plants offer a naturally balanced synergy of compounds that work together to support healing, reduce side effects, and improve absorption. Unlike isolated chemicals, the full spectrum of constituents in a plant can enhance each other’s benefits and moderate potential drawbacks. 

For instance: 

Meadowsweet (Filipendula ulmaria)

Meadowsweet is a beautiful example of how the synergy of whole-plant medicine offers healing that is both effective and gentle. Best known for natural salicylates—the same class of compounds that led to the development of aspirin—meadowsweet has traditionally been prescribed for pain relief, fever, and digestive complaints. But unlike aspirin, which can cause gastric irritation or even ulceration, meadowsweet soothes and protects the digestive tract. This key difference lies in the plant’s complex chemistry and internal balance.

Isolated Compound vs. Whole Plant

Aspirin (acetylsalicylic acid) was originally synthesized from salicylate-containing herbs like willow and meadowsweet. When isolated, salicylates can be harsh on the stomach, inhibiting prostaglandins that protect the gastric lining. Aspirin, while powerful, lacks the buffering, balancing agents found in the whole plant, making it prone to causing inflammation or damage in sensitive individuals.

In contrast, meadowsweet contains not just salicylates, but also:

• Mucilage – which coats and soothes the digestive lining
• Tannins – which have an astringent, toning effect and help reduce inflammation
• Flavonoids – offering antioxidant and anti-inflammatory support
• Volatile oils – contributing to mild antimicrobial and digestive effects

This synergistic blend means that while meadowsweet reduces pain and inflammation (via salicylates), it simultaneously protects and supports the digestive system—particularly useful for those prone to gastric sensitivity or using other medications.

Liquorice Root (Glycyrrhiza glabra)

Liquorice root is another example of the intelligence of whole-plant medicine. While often recognised for its sweet taste and adrenal-supportive properties, liquorice is a complex, multi-constituent herb whose safety and effectiveness rely on the synergy of the compounds.

The key active constituent most people associate with liquorice is glycyrrhizin, a triterpenoid saponin that:

Supports adrenal function by slowing the breakdown of cortisol (cortisol-sparing)

Acts as an anti-inflammatory by modulating immune responses

Functions as a mild expectorant in respiratory conditions

However, isolated glycyrrhizin, especially in large or long-term doses, can lead to elevated blood pressure, fluid retention, or potassium imbalance. This has led to caution around its use, particularly in people with hypertension or kidney concerns.

Yet, in the whole root, glycyrrhizin is accompanied by:

• Flavonoids – which offer antioxidant, anti-inflammatory, and calming effects
• Polysaccharides and mucilage – that soothe mucous membranes, reduce irritation in the digestive and respiratory tracts, and balance the root’s natural stimulation
• Chalcones and isoflavones – contributing to liver support and estrogen modulation
• Volatile oils – adding mild antimicrobial and spasmolytic action

These constituents temper the intensity of glycyrrhizin, making the whole herb gentler, safer, and more harmonised. Rather than overstimulating, liquorice root in its whole form can uplift depleted states while nourishing and calming irritated or inflamed tissues—particularly in the lungs, gut, and adrenals.

Mint (Mentha spp.)

Mint offers another good example of how whole-plant synergy enhances both safety and effectiveness. Species like Mentha piperita (peppermint) and Mentha spicata (spearmint) contain a broad range of constituents that work together to create its signature cooling, digestive, and uplifting effects.

The primary active compound often associated with peppermint is menthol—a monoterpene alcohol known for its cooling, analgesic, and antispasmodic actions. Menthol alone, when isolated and concentrated (as it is in some pharmaceutical applications or flavorings), can be overpowering or irritating, especially to the skin, mucous membranes, or in the digestive tract in sensitive individuals. In isolation, menthol lacks the buffering effect of the other constituents found in whole mint.

However, in the whole plant, menthol is accompanied by a wide array of synergistic compounds, such as:

• Menthone – with mild sedative properties
• Rosmarinic acid – anti-inflammatory and antioxidant
• Flavonoids – that support vascular tone and have a calming effect
• Tannins – which offer a mild astringency to balance excessive moisture
• Volatile oils – that gently stimulate digestion and reduce bloating

Together, these constituents modulate the intensity of menthol’s action. For instance, the soothing flavonoids and anti-inflammatory rosmarinic acid help reduce the potential for irritation that menthol might cause on its own. This synergistic matrix allows mint to be both stimulating and soothing, making it especially useful for conditions like digestive upset with accompanying tension, mild headaches, or even cognitive fatigue.

Understanding Herbal Constituents

This holistic interplay—known as synergy—is one of the key reasons why traditional herbal medicine often proves gentler and more effective than isolated pharmaceutical compounds. Understanding herbal constituents helps bridge the gap between tradition and science. When you know what’s in your herbs, how to best extract the medicine you are after you’re practicing informed, intelligent herbal medicine making.

These blog articles are herbal education resources,  produced by the Seed Sistas. Gain insights and join us in the evolution of healthcare, please do leave a comment or question.  Wellbeing empowerment for all…