Bioactive Components and Biological Functions of Honey

Honey is a natural sweet substance produced by honeybees from the nectar of plants, secretions of living plant parts, or excretions of plant-sucking insects, which the bees collect, transform, combine with their own specific substances, store, and leave to ripen in honeycombs (Zhang et al., 2024).

Honey contains a wide variety of bioactive components, including carbohydrates, proteins, enzymes, minerals, amino acids, polyphenols, and vitamins (Silva et al., 2019). These compounds endow honey with multiple functional activities, such as antibacterial, antioxidant, anti-inflammatory, gastrointestinal-regulating, and wound-healing properties (Zeng et al., 2023). The physicochemical properties and functional activities of honey are influenced by nectar source, seasonal variation, climatic conditions, and geographical factors (Marianna et al., 2021).

As a natural functional food, honey exhibits significant potential in adjunctive disease therapy, particularly due to its antibacterial properties and prebiotic effects (Sarfraz et al., 2018). Studies have shown that honey is rich in phenolic acids, lysozyme, and specific carbon-nitrogen structures, which act synergistically to inhibit the proliferation of bacteria in honey and maintain intestinal microbiota homeostasis (Grabowski et al., 2016). Current evidence confirms that these bioactive components exert marked inhibitory effects against common pathogens such as Staphylococcus aureus and Escherichia coli (Al-Waili et al., 2012).

Main Nutritional Components of Honey

To date, several hundred components have been documented in honey. The major nutritional constituents include carbohydrates, proteins, organic acids, minerals, and polyphenolic compounds. The content of these nutrients varies depending on the botanical origin and geographical conditions of the honey.

Carbohydrates: the primary energy source of honey

Carbohydrates, including glucose, fructose, maltose, and sucrose, account for approximately 80% of honey’s composition (Ji et al., 2024). Glucose and fructose are the most abundant sugars, representing 85–90% of the total carbohydrate fraction (Tan et al., 2016).

The quality of honey is closely related to its carbohydrate profile. Glucose and fructose not only impart sweetness but also participate in the Maillard reaction, generating distinctive flavour compounds that influence honey’s colour, aroma, and taste. Furthermore, honey is susceptible to temperature-induced crystallisation (Tan et al., 2016): at low temperatures, the reduced solubility of glucose leads to the formation of a crystal lattice, causing crystallisation. Consequently, honey with a higher glucose content tends to crystallise more readily.

The high concentration of carbohydrates is a key factor in honey’s antibacterial activity. The underlying mechanism involves the high osmotic pressure created by a sugar-rich environment, which reduces water activity and thereby inhibits microbial growth (Juraj M et al., 2021). The antibacterial efficacy of honey varies depending on the osmotic tolerance of the bacteria and the carbohydrate concentration of the honey. Some osmotolerant yeasts can survive the high osmotic pressure of honey, leading to fermentation (Wang et al., 2022). Thus, the antibacterial activity of honey is closely linked to its carbohydrate concentration, providing a scientific basis for its application in antibacterial therapy (Lokman et al., 2022).

Water content: a key indicator of honey quality

The water content of honey ranges from approximately 13% to 25% and is a critical parameter for evaluating honey quality and stability (Wang et al., 2018). Moisture content is closely associated with honey’s physical properties, shelf life, and nutritional value.

An appropriate amount of water facilitates the orderly arrangement of glucose molecules under suitable conditions to form crystal nuclei, thereby promoting crystallisation (Institute of Food Engineering for Development, 2017). Water content directly affects honey’s viscosity: when water content is low, honey exhibits a highly viscous liquid or semi-solid state.

Water acts as a solvent in many chemical reactions within honey. Excessive water content accelerates enzymatic reactions and non-enzymatic browning, and may also lead to fermentation and spoilage (Li et al., 2024), thereby compromising honey’s nutritional value and food safety.

Proteins and enzymes: the active essence of honey

The protein content of honey is approximately 0.2–1.0%, consisting mainly of various enzymes such as glucose oxidase, α-glucosidase, catalase, acid phosphatase, diastase (amylase), and peroxidase (Flanjak I et al., 2016).

The levels of these enzymes are closely related to honey’s protein content, and they play critical roles both during honey ripening and in human digestion and absorption. Diastase breaks down starch, while glucose oxidase catalyses the oxidation of glucose to produce hydrogen peroxide, thereby endowing honey with antibacterial and anti-inflammatory properties. These enzymes contribute significantly to honey’s functional properties and health benefits. Moreover, diastase activity is positively correlated with honey freshness and nutritional value.

In addition, honey contains small amounts of royal jelly, which is inadvertently incorporated during honey production and represents another source of protein in honey (Zhang et al., 2025).

Organic acids: the source of honey’s acidity

Honey contains approximately 0.5% organic acids and has a pH between 3.5 and 4.5, indicating moderate acidity. The organic acid profile of honey is diverse, including formic acid, acetic acid, gluconic acid, citric acid, and others (Li et al., 2023).

Gluconic acid and citric acid are the predominant organic acids in honey and serve as important markers for distinguishing nectar sources. Formic acid and acetic acid are volatile and contribute to the characteristic aroma of honey (Faculty of Food Engineering S C M U, 2020). The mildly acidic environment is another factor that enables honey to inhibit the growth of certain microorganisms.

Minerals: a trace element treasure trove

Honey contains a variety of minerals, including macro- and micro-elements such as potassium, calcium, sodium, magnesium, iron, zinc, copper, manganese, and phosphorus (Ji et al., 2024).

Metal ions such as iron and copper in honey can act as catalysts, promoting the oxidation of sugars and phenolic compounds, thereby generating distinctive flavour substances. In addition, minerals play essential roles in maintaining normal physiological functions in humans, including regulation of enzyme activity, maintenance of electrolyte balance, and support of metabolic reactions.

In honey, minerals help maintain water stability by modulating osmotic pressure and water activity, thereby effectively inhibiting microbial growth, fermentation, and spoilage (Zhang et al., 2025).

Vitamins: micronutrient supplementation

Honey contains a range of vitamins, mainly B vitamins (such as B₁, B₂, B₆, niacin, pantothenic acid, biotin), vitamin C, vitamin K, and small amounts of vitamins A, D, and E. Among these, vitamin C is the most abundant, with concentrations ranging from 0.34 to 75.9 mg/100 g, and it is present in almost all types of honey (Zhang et al., 2025).

Vitamin C possesses strong antioxidant activity, enhances immunity, and promotes collagen synthesis (Sun et al., 2017). Vitamin K contributes to bone health and blood coagulation (Yu et al., 2010). Honey can serve as an important dietary source of vitamins, providing the body with multiple essential nutrients.

Other bioactive components

In addition to the substances mentioned above, honey contains polyphenolic compounds (mainly phenolic acids and flavonoids) as well as other phytochemicals such as terpenes, alcohols, aldehydes, and alkaloids (Li, 2024). These compounds are the primary contributors to honey’s antioxidant activity and constitute the material basis for the specific functional properties of honey from different floral sources.

Conclusion

In summary, honey is a compositionally complex and functionally diverse natural food. Its nutritional value arises from the synergistic action of multiple compounds. Carbohydrates form its basic structural framework; enzymes and organic acids participate in metabolic regulation; minerals and vitamins maintain physiological functions; and polyphenolic substances confer significant antioxidant properties. Current research has confirmed that the chemical composition of honey is influenced by multiple factors, including nectar source, geographical origin, and climatic conditions. These findings provide a theoretical basis for the origin traceability and quality authentication of honey.

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