The study, conducted by researchers at Mae Fah Luang University and Chiang Mai University, reported that honeysuckle flower extract (HSF) was rich in phenolic and flavonoid compounds, with strong antioxidant properties.
Computational docking suggested these compounds could inhibit enzymes linked to ageing and inflammation, including collagenase, hyaluronidase, and TNF-α.
Encapsulation in polyglycerol fatty acid ester (PGFE)-based nanoemulsions further improved its stability and delivery, with an encapsulation efficiency of more than 74%.
This was said to be the first study to integrate a D-optimal design nanoemulsion with in-depth chemical profiling and molecular docking of honeysuckle extract. Its findings highlighted HSF’s potential as a multifunctional cosmetic ingredient.
Honeysuckle’s cosmeceutical potential
Honeysuckle, long used in traditional Chinese medicine under the name Jinyinhua, is valued for its anti-inflammatory and anti-microbial properties.
In cosmetics, its flowers have been gaining attention for their richness in bioactive phytochemicals, including chlorogenic acid, caffeic acid, luteolin, quercetin, and rutin.
These compounds offer multiple benefits relevant to skin care, including antioxidant protection, anti-inflammatory action, UV defence and repair, and skin regeneration. They can help scavenge radicals that accelerate ageing, and calm irritation and redness.
In addition, chlorogenic and caffeic acids can help reduce UV-induced skin damage, and saponins such as madecassoside can stimulate collagen synthesis and wound healing.
Extract characterisation and antioxidant activity
Using supercritical CO₂ extraction, the research team obtained an HSF yield of 6.4%, resulting in a dark green viscous extract. Chemical analysis confirmed high levels of total phenolics (155 mg gallic acid equivalents per gram) and flavonoids (nearly 400 mg quercetin equivalents per gram).
UHPLC-QTOF-MS/MS profiling identified 19 compounds, including five phenolic acids, eight flavonoids, two iridoids, and four saponins. Notable compounds included chlorogenic acid, hyperoside, cynaroside, congmunoside XII, dipsacoside B and madecassoside.
These phytochemicals are cosmetically valuable for skin hydration, anti-wrinkle activity, UV protection, and reducing pigmentation and scars.
Additionally, antioxidant testing confirmed the extract’s potency. In the DPPH assay, HSF showed an IC50 of 1.65 mg/mL, reflecting strong radical scavenging ability. In the FRAP assay, it achieved 1.17 mM FeSO₄ equivalents per gram, close to ascorbic acid’s reducing power.
Phenolic acids and flavonoids, especially chlorogenic acid and quercetin derivatives, were found to be the main contributors to this antioxidant activity.
Molecular docking points to anti-ageing and anti-inflammatory mechanisms
To predict biological activity, the researchers docked six major compounds against enzymes and cytokines linked to ageing and inflammation.
The results showed strong binding affinities (below –6 kcal/mol) across targets. For instance, madecassoside bound strongly to collagenase (–9.3 kcal/mol) and elastase (–8.3 kcal/mol), supporting anti-wrinkle and collagen-preserving effects.
Cynaroside interacted with IL-1β (–7.9 kcal/mol), suggesting anti-inflammatory activity, and hyperoside bound IL-6 (–8.3 kcal/mol), indicating modulation of inflammatory pathways.
Finally, congmunosideXII showed the strongest binding to hyaluronidase (–10.7 kcal/mol) and also to TNF-α (–9.1 kcal/mol), pointing to dual anti-ageing and anti-inflammatory effects
These findings revealed that honeysuckle flower compounds could target both structural enzymes and inflammatory mediators, reinforcing their multifunctionality in skin health.
Delivery system
To enhance delivery, the team developed nanoemulsions using PGFEs, a class of eco-friendly, plant-derived surfactants.
Using a D-optimal experimental design, they optimised several key formulation parameters to produce nanoemulsions with droplet sizes under 100nm, polydispersity index below 0.2, and an encapsulation efficiency of 74.3%.
The researchers reported that transmission electron microscopy confirmed spherical droplets with stable morphology. This optimised system also maintained antioxidant activity while enhancing solubility, stability, and potential skin permeability.
When tested in the DPPH assay, the HSF nanoemulsions achieved 94.7% radical inhibition, only slightly lower than the 97.1% inhibition of free HSF extract. This demonstrated that encapsulation preserved the extract’s antioxidant capacity while offering the added benefits of controlled release and enhanced dermal delivery.
Industry implications
The study highlighted HSF as a candidate for premium skin care targeting oxidative stress, inflammation, and skin ageing.
The researchers found that the integration of PGFE-based nanoemulsions offered both functional and marketing advantages — namely, green technology, enhanced efficiency, and multifunctionality, and traditional-meets-modern positioning.
For example, low-energy emulsification with plant-based surfactants could be used to support sustainability claims, while nano-sized carriers improved solubility, penetration, and stability of bioactives.
In addition, active compounds acted on multiple anti-ageing and anti-inflammatory pathways.
This latest research combined established use in traditional medicine with advanced delivery science, with HSF-loaded nanoemulsions representing a new generation of natural, multifunctional cosmeceutical ingredients.
Next steps
While computational and formulation data were strong, the authors emphasised the need for further validation. They recommended that in future, studies should focus on enzymatic inhibition assays, cell-based anti-inflammatory models, and skin penetration testing to confirm in silico predictions.
Nevertheless, the study provides a foundation for commercial development. The researchers concluded: “Crucially, this work not only establishes the scientific rationale for HSF-based nano-formulations, but also presents a replicable platform for translating traditional medicinal ingredients into modern skin care innovations.
“These efforts will bridge the gap between computational predictions and clinical relevance, enabling the development of safe, sustainable, and efficacious plant-based cosmeceutical products.”
Source: Cosmetics
“Unlocking the Skin Health-Promoting Ingredients of Honeysuckle (Lonicera japonica Thunberg) Flower-Loaded Polyglycerol Fatty Acid Ester-Based Low-Energy Nanoemulsions”
https://doi.org/10.3390/cosmetics12040151
Authors: Nara Yaowiwat, et al.
