Plant-based actives, (aka phytochemicals) are a broad class of ingredients that are extracted from plant matter which can produce physiological effects. These compounds are therefore considered bioactive and can be either nutrients (see for example: Whitepaper on harnessing plant protein | Sagentia Innovation) or non-nutritive. In this insight, we focus on the latter, but of course, there are many other applications for plant-based ingredients, for example, in ‘natural’ home hygiene applications (see: Home hygiene: navigating natural ingredients (sagentiainnovation.com)).
Why might we be interested in plant-based actives in delivering experience?
Plant-based actives can elicit a range of responses in the human body including:
- Psychoactive ingredients that affect the nervous system, for example, stimulants such as caffeine and nicotine
- Sensates which deliver sensations such as heat (capsaicin), cooling (menthol) or ‘tingling’ sensations (gingerol)
- Flavours and fragrances which activate taste and scent receptors and drive an emotional response (for example liking). The physiological mechanism of flavour perception is complex and not fully understood with a range of relevant receptors and reliance on other sensory inputs[i]
In some cases, a phytochemical may combine two or more of these functions, for example, cinnamaldehyde, which acts as an antioxidant but also has an anti-inflammatory effect, gives flavour to cinnamon, and elicits a tingling sensation.[i]
Why use plant-based actives?
Consumer preference is increasing towards naturalness in the food & beverage industry, which is driving a shift from synthetic ingredients to plant-based alternatives. Ingredient manufacturers are helping with this switch with an ever-increasing range of plant-based actives including flavours, preservatives, and sweeteners. Indeed, over 10,000 of these bioactive plant chemicals have been identified in grains, vegetables and fruit which may show potential in a large range of formulation applications.[i]
As an example, some key plant actives found in food, beverage and consumer products and their interactions with human physiology are set out below:
- Caffeine is one of the best known bioactives – found in coffee and tea plants and is used in energy drinks and a range of sports nutrition products. Caffeine is very rapidly absorbed after ingestion with 99% absorbed within 45 minutes of ingestion, typically through the GI tract. Formulations that allow absorption through the oral mucosa, such as chewing gum, can speed up the absorption further. The physiological effects of caffeine are linked to the inhibition of adenosine receptors which are normally linked to fatigue[i]
- Nicotine is an alkaloid found in the leaves of tobacco plants which releases dopamine in the brain by binding to nicotinic cholinergic receptors (nAChRs). In most tobacco products, the nicotine is absorbed via the lungs into the pulmonary venous circulation and can move rapidly into the brain. However, absorption can also occur through the skin, oral mucosa, and gut[ii]
- Sensates can activate receptors typically associated with other physical responses such as temperature, touch, and pain. These chemicals typically work by activating TRP channels found in cells in the mouth and on the skin. By eliciting chemesthetic effects such as cooling, warming, and tingling, these ingredients can add interest to a range of products and are often combined with flavours. Common examples include menthol, a terpene alcohol found in mint, which elicits a cooling effect. This effect makes it a popular ingredient to add to oral care products, chewing gums etc. Examples of plant-based sensates and their physiological mode of action are shown in Table 1
Plant | Chemical | Effect | Mode of action |
---|---|---|---|
Mint | Menthol | Cooling | Activates TRPM8 channel (cold receptor) |
Ginger | Gingerol | Tingling/burning | Activates TRPV1 channel |
Cinnamon | Cinnamaldehyde | Warming/tingling/spicy | Activates TRPA1 |
Cloves | Eugenol | Numbing/tingling/warming | Activates TRPV3 and TRPV1 |
Sichuan peppercorns | Sanshool | Tingling/mouth watering | Excitation of neurons by the inhibition of pH sensitive two-pore potassium channels |
Delivering the Consumer Experience
Routes by which a phytochemical can enter the body include via the digestive tract, oral mucosa, lungs, and skin. When considering bioactives, the route must be chosen to match the required effect. For example, nicotine can be introduced by all the aforementioned routes, but the pharmokinetics of uptake vary significantly between inhalation, oral consumption, and dermal absorption. In contrast sensate phytochemicals are typically delivered through the skin or the oral mucosa and flavours through taste and scent receptors in the mouth and nose.
Various delivery formats are available which can be used to ensure that phytochemicals can be successfully targeted to the correct physiological ‘target’.