*Corresponding author: Eun-Jun Park Tel : +82-2-940-7846 E-mail : I. Introduction
Environmental pollution, including exposure to UV radiation, particulate matter, and harmful chemicals, has become a significant concern for skin health, leading to oxidative stress and chronic inflammation (Yun & Baek, 2023; Lee & Seo, 2024). The skin, being the body's primary barrier against external pollutants, is particularly susceptible to damage from these environmental stressors, resulting in premature aging, pigmentation, and inflammatory skin conditions (Cho & Kang, 2021). In recent years, plant extracts with antioxidant and anti-inflammatory properties have garnered attention for their potential to mitigate the harmful effects of environmental pollution on skin health (Michallak, 2022; Fernandes et al., 2023; Shuayr, 2023). Several studies have demonstrated that plant-derived compounds can neutralize reactive oxygen species (ROS) and reduce inflammatory cytokine production, offering protective effects against skin damage caused by pollution (Gonfa et al., 2023; Kim et al., 2025).
The global cosmetic industry is experiencing a paradigm shift towards natural and plant-based ingredients, reflecting consumer demand for safer, eco-friendly, and multifunctional products (Liu, 2022).
Sargentodoxa cuneata (family: Lardizabalaceae) has long been used in traditional East Asian medicine for the treatment of inflammatory diseases, infections, and pain (Hu et al., 2020). Numerous studies have identified a variety of bioactive compounds in this plant, including phenolics, lignans, triterpenes, and phenylpropanoids, which support its medicinal value (Chen et al., 2009; Tang et al., 2012). Despite these findings, its application in the cosmetics industry remains limited, and further studies are needed to explore its potential as a functional ingredient for skin health.
Recent studies have reported various pharmacological effects of S. cuneata extracts, including anti-inflammatory (Ma et al., 2015), anti-oxidant (Zhang et al., 2021), antimicrobial(Chen et. al., 2024), and wound-healing properties (Xu et al., 2024). Particularly, the stem extract has demonstrated free radical scavenging activity, suppression of pro-inflammatory mediators, and enhancement of skin barrier function (Yuanyuan et al., 2024). These properties are closely associated with skin health and suggest its potential use as a cosmetic ingredient targeting skin aging, sensitivity, and hyperpigmentation.
Although numerous biological activities of S. cuneata have been reported, its application in the field of cosmetics— particularly for anti-aging purposes—remains underexplored. Therefore, there is a growing need to investigate and scientifically validate the potential of S. cuneata stem extract as a novel cosmetic raw material. This study aims to evaluate the bio-functional properties of the extract, including its antioxidant, anti-inflammatory, and skin-whitening effects, to determine its suitability as a functional ingredient in modern cosmetic formulations.
By developing functional cosmetics using natural plant resources like S. cuneata, this research contributes to the expansion of eco-friendly and effective cosmetic materials, in line with current trends in the global beauty industry.
II. Materials and Methods
1. Extraction and fractionation of S. cuneata stem
Dried stems of S. cuneata (500 g) were extracted with 5 L of methanol (MeOH) at room temperature. The resulting extract was concentrated under reduced pressure to yield a crude MeOH extract (75 g). The MeOH extract was suspended in distilled water (DW) and successively partitioned with dichloromethane (DCM), ethyl acetate (EA), and n-butanol (Bu). Each fraction was evaporated to dryness under reduced pressure and stored at -20°C until further analysis.
2. Radical scavenging assay
1) DPPH radical scavenging assay
The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay was employed to assess the antioxidant effectiveness of each fraction. The anti-oxidant activity of each fraction was evaluated using the (DPPH) radical scavenging assay. Various concentrations (0.01, 0.02, 0.05, 0.1, 0.5, and 1.0 mg/mL) of each sample were mixed with 0.1 mM DPPH solution in methanol and incubated in the dark at room temperature for 30 minutes. The absorbance was measured at 517 nm using a microplate reader.
2) ABTS radical scavenging assay
The ABTS radical cation (ABTS⁺•) was generated by reacting 7 mM ABTS[2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] solution with 2.45 mM potassium persulfate. The ABTS⁺• solution, incubated in the dark at room temperature for 12-16 h, was diluted with ethanol to an absorbance of 0.70 ± 0.02 at 734 nm. Each sample fraction was prepared at various concentrations (0.01, 0.02, 0.05, 0.1, 0.2, 0.5, and 1.0 mg/mL) and mixed with the diluted ABTS⁺• solution (1:9, v/v). After incubation at room temperature for 10 minutes, the absorbance was measured at 734 nm using a microplate reader.
3. Anti-inflammatory assay in RAW 264.7 cells
1) RAW264.7 cell culture
Cells were cultured in RPMI containing 10% FBS and 1% antibiotics solution under standard conditions. (37°C, 5% CO2). Cells were seeded in 96-well plates and pre-treated with various concentrations (0.02, 0.05, 0.1, 0.2, and 0.4 mg/mL) of each S. cuneata fraction (SCDCM, SCEA, SCB, and SCDW) for 1 hour. Lipopolysaccharide (LPS, 0.1 μg/mL) was then added and incubated for an additional 24 hours.
2) Nitric oxide (NO) assay
NO production was measured using the Griess reagent. Following 24 hours of LPS stimulation, 100 μL of culture supernatant was combined with an equal volume of Griess reagent and incubated at room temperature for 10 minutes. The absorbance was measured at 540 nm, and NO concentration (μM) was calculated using a standard curve generated with sodium nitrite.
4. Astringent activity assay
The astringent activity of S. cuneata fractions was assessed based on protein-precipitation ability using the tannic acid (TA) standard method. Briefly, 50 μL of each sample (0.1, 0.2, 0.5, and 1.0 mg/mL) was mixed with 50 μL of 1% bovine serum albumin (BSA) in phosphate-buffered saline (PBS, pH 7.4). After incubation at room temperature for 30 minutes, the mixtures were centrifuged at 10,000 rpm for 10 minutes, and the absorbance of the supernatant was measured at 595 nm. Tannic acid (TA) was used as a positive control.
5. Anti-aging enzyme inhibition assays
1) Collagenase inhibition assay
The collagenase inhibitory activity was measured using a commercial collagenase from Clostridium histolyticum. The reaction mixture contained 0.8 units/mL collagenase in Tricine buffer (50 mM, pH 7.5), 0.2 mM FALGPA (N-[3-(2-Furyl)acryloyl]-Leu-Gly-Pro-Ala), and test samples (SCDCM, SCEA, SCB, SCDW). After incubation at 37°C for 20 minutes, the decrease in absorbance was measured at 340 nm. Phosphoramidon (PT) was used as a positive control. Inhibition rate (%) was calculated by comparing absorbance with the untreated control.
2) Elastase inhibition assay
Elastase inhibitory activity was evaluated using porcine pancreatic elastase and N-Succinyl-Ala-Ala-Ala-p-nitroanilide (SANA) as a substrate. Test samples were pre-incubated with elastase (1 U/mL) for 15 minutes, followed by the addition of the substrate. After incubation at 25°C for 30 minutes, absorbance was read at 410 nm. Elastatinal was used as the positive control. Inhibition rate (%) was calculated relative to the negative control.
6. Whitening activity assays
1) DOPA oxidation inhibition assay
The inhibition of L-DOPA oxidation was evaluated as an indirect measure of melanin synthesis inhibition. Briefly, each S. cuneata extract fraction (SCDCM, SCEA, SCB, and SCDW) was mixed with a reaction solution contaning 1 mM L-DOPA and mushroom tyrosinase (100 U/mL) in phosphate buffer (pH 6.8). The mixture was then incubated at 37°C for 30 minutes, after which the absorbance was measured at 475 nm. Arbutin (AR) was used as a positive control. The inhibition rate (%) was calculated based on absorbance changes relative to the control.
2) Tyrosinase inhibition assay
Tyrosinase inhibitory activity was determined using L-tyrosine as a substrate. Each sample was incubated with mushroom tyrosinase (100 U/mL) and 0.1 mM L-tyrosine in phosphate buffer (pH 6.8) at 37°C for 30 minutes. The absorbance was measured at 490 nm. Arbutin was used as a positive control.
7. Statistical analysis
All the data were performed in triplicate and were represented as mean ± standard deviation (SD) using Microsoft Excel 2019 software (Microsoft Office, Microsoft Corporation, Redmond, WA, USA). Statistical significance between multiple groups was analyzed by one-way ANOVA with Tukey’s post hoc test using SPSS 20 software (SPSS Inc., Chicago, IL, USA). p value < 0.05 was considered as the statistically significant level.
III. Results and Discussion
1. Preparation of stem fractions
The partitioning process yielded the following solvent fractions: DCM fraction (19.2 g), EA fraction (9.6 g), Bu fraction (46.9 g), Remaining DW fractions were also collected after each partitioning step (Fig. 1).
2. Anit-oxidant effect of S. cuneata stem fractions
The anti-oxidant activities of S. cuneata fractions were evaluated using DPPH assay, ABTS assays as well as total polyphenol content (TPC) analysis (Table 1).
Among the tested fractions, the ethyl acetate fraction (SCEA) showed the most potent anti-oxidant activity with low IC50 values in both DPPH (11.830 ± 0.013 μg/mL) and ABTS (55.498 ± 0.097 μg/mL) assays (Fig. 2). As shown Table 1, SCEA also exhibited the highest total polyphenol content (233.975 ± 5.762 mg GAE/g). These results suggest that the anti-oxidant activity of S. cuneata is closely correlated with its polyphenol content, particularly in the ethyl acetate fraction.
These findings are similar with the findings of previous research who reported that S. cuneata contains phenolics, phenolic glycosides, flavonoids, triterpenoids, and lignans (Zhang et al., 2021).
3. Anti-inflammatory effect of S. cuneata stem fractions
As shown in Fig. 3A, all S. cuneata fractions dosedependently suppressed NO production in LPS-stimulated RAW 264.7 cells. Among them, the SCEA and SCB fractions exhibited the most potent inhibitory effects, showing marked reductions even at lower concentrations (0.05 mg/mL).
Similarly, IL-6 secretion was also significantly reduced by the fractions in a concentration-dependent manner (Fig. 3B). SCEA demonstrated the strongest suppression of IL-6 production, followed by SCB. SCDCM and SCDW showed moderate but consistent inhibitory effects.
Ma et al. demonstrated that both the ethyl acetate and aqueous fractions derived from the ethanol extract of S. cuneata significantly reduced the expression levels of proinflammatory cytokines IL-1 and TNF-α in peritoneal macrophages (Ma et al., 2015). These findings support the ethnopharmacological use of S. cuneata in the treatment of rheumatic arthritis.
4. Astringent effect of S. cuneata stem fractions
As shown in Fig. 4, tannic acid (TA), used as a positive control, exhibited strong astringent activity, reaching nearly 100% at concentrations of 0.5 and 1 mg/mL. Among the S. cuneata fractions, SCB showed the highest astringent activity, displaying over 50% at 1.0 mg/mL. SCDCM exhibited moderate astringent effects in a dose-dependent manner, while SCEA and SCDW showed relatively weak activity at all tested concentrations.
These results suggest that certain fractions of S. cuneata, particularly SCB and SCDCM, possess potential astringent properties, which may be beneficial for cosmetic applications such as pore-tightening or sebum control.
The astringent activity observed in the butanol and dichloromethane fractions may be attributed to the presence of polyphenolic compounds such as tannins and non-polar constituents like triterpenoids and lignans, which are known to induce tissue contraction (Mohammed & Kadhim, 2025; Shahrraki et al., 2023).
5. Inhibitory effects on collagenase and elastase activity
As shown in Fig. 5A, SCB exhibited the highest collagenase inhibitory activity among the S. cuneata fractions, reaching approximately 30% inhibition at 1.0 mg/mL. Other fractions, including SCDCM, SCEA, and SCDW, showed minimal inhibition, indicating limited anti-collagenase potential.
Regarding elastase inhibition (Fig. 5B), SCDCM demonstrated the highest activity among the test fractions, showing up to ~20% inhibition at 1.0 mg/mL. SCEA and SCB showed weak activity, while SCDW displayed negligible effects. In contrast, the positive control elastatinal inhibited over 60% of elastase activity.
Based on the results of this study and the U.S. patent indicating that plant extracts containing S. cuneata promote collagen I production, S. cuneata extract is considered to have high potential as a functional anti-aging cosmetic ingredient for improving skin elasticity (Florence et al., 2023).
6. Whitening activity of S. cuneata fractions
As illustrated in Fig. 6A, the DOPA oxidation inhibitory activity of S. cuneata fractions increased in a dose-dependent manner. Among the test samples, SCDW exhibited the highest activity, reaching approximately 30% inhibition at 1 mg/mL. SCDCM and SCB also showed moderate activity, whereas SCEA demonstrated relatively low inhibitory effects.
In the tyrosinase inhibition assay (Fig. 6B), SCDW again showed the highest inhibition among the S. cuneata fractions, albeit at a lower level compared to the positive control arbutin, which inhibited tyrosinase by over 80%. The other fractions exhibited marginal or negligible tyrosinase inhibitory effects.
These results, together with the Canadian patent CA2831597 describing the biological activities of S. cuneata extract, including its tyrosinase inhibitory effect, suggest that S. cuneata extract has potential as a skin-brightening agent for use in cosmetic formulations.
Ⅳ. Conclusion
The present study demonstrated that S. cuneata stem extract possesses diverse bioactivities highly relevant to cosmetic applications. Each solvent fraction exhibited distinct functional properties. Notably, the ethyl acetate fraction (SCEA) showed the strongest antioxidant and antiinflammatory effects, which are key mechanisms involved in skin aging and sensitivity. These effects are likely associated with its high polyphenol content, as supported by previous studies reporting abundant phenolic compounds, flavonoids, and lignans in S. cuneata (Zhang et al., 2021). The butanol (SCB) and dichloromethane (SCDCM) fractions exhibited significant astringent and anti-collagenase/elastase activities, suggesting their potential in anti-aging formulations aimed at improving skin elasticity, tightening pores, and reducing wrinkles. Meanwhile, the aqueous fraction (SCDW) showed the most potent skin-brightening activity via tyrosinase and DOPA oxidation inhibition, which are critical targets in hyperpigmentation treatment. These results indicate that S. cuneata stem extract can serve as a multifunctional ingredient for the development of skincare products targeting aging, inflammation, dullness, and uneven tone.
Although the bioactivities of S. cuneata fractions are promising, practical application in aqueous-based cosmetics is limited by solubility issues, especially for non-polar and semi-polar extracts. To address this, formulation strategies were optimized according to the polarity of each fraction. Non-polar fractions such as DCM and semi-polar fractions such as EA exhibited poor water solubility; thus, co-solvent systems (e.g., ethanol:BG:water) and non-ionic solubilizers such as PEG-40 hydrogenated castor oil and polysorbate 20 were utilized to enhance dispersion in water. In some cases, advanced delivery systems such as nanoemulsions and liposomes were considered to ensure both physical stability and improved dermal penetration of hydrophobic compounds. For the moderately polar butanol fraction (SCB), direct dissolution using hydrophilic solvents (e.g., BG, PG) was sufficient to achieve uniform formulation. The water fraction (SCDW), being highly polar, required no further solubilization. These tailored strategies enabled effective incorporation of all fractions into aqueous formulations, ensuring both functional integrity and bioavailability of the active components. This highlights the importance of polarity-based formulation approaches when utilizing plantderived extracts in cosmetic applications (Mohammed & Kadhim, 2025; Florence et al., 2023).
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