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INTRODUCTION
The cosmetic industry has grown rapidly due to increasing consumer interest in beauty and personal care products. Lipsticks are among the most widely used cosmetics; however, conventional formulations often contain synthetic dyes and additives associated with adverse effects such as irritation, allergic reactions, and possible carcinogenicity (Mawazi et al., 2022). These concerns have increased interest in herbal cosmetics containing safer and environmentally sustainable natural ingredients.
Plant-derived pigments are being widely explored as alternatives to synthetic colorants because of their low toxicity, biodegradability, and additional biological properties such as antioxidant and antimicrobial activities (Patil et al., 2025). Several studies have reported the successful use of botanical pigments in herbal lipstick formulations with good stability and safety profiles (Raji et al., 2025).
Butea monosperma (Fabaceae), commonly known as “Flame of the Forest” or “Palash,” contains bright orange-red pigments rich in flavonoids, chalcones, and aurones, which possess antioxidant, antimicrobial, and anti-inflammatory activities (Sourabh et al., 2023). These phytochemicals may provide additional protective benefits to lip tissue exposed to environmental stressors (Michalak et al., 2023). However, limited studies are available on the use of Butea monosperma flower extract in lipstick formulations.
Therefore, the present study aimed to formulate and evaluate a herbal lipstick using aqueous extract of Butea monosperma flowers as a natural colorant. Three formulations were prepared to optimize pigment incorporation and physical stability. The optimized formulation was evaluated for organoleptic properties, melting point, spreadability, stability, pH, skin irritation, and FTIR compatibility to assess its suitability as a safe and stable herbal cosmetic product.
MATERIALS AND METHODS
All chemicals used were of analytical reagent grade and were procured from SRL Chemicals. FTIR analysis was performed using a Bruker FTIR spectrophotometer. Evaluation parameters were selected according to BIS guidelines for cosmetic lipsticks (BIS 9875:1990).
Collection and Authentication of Plant Material
Fresh flowers of Butea monosperma were collected from the Narsapur forest area near our institution. The plant material was taxonomically authenticated by Dr. Madhava Chetty, Associate Professor, Department of Botany, Sri Venkateswara University, Tirupati.
Animals
New Zealand rabbits of either sex weighing approximately 2 kg were used for the skin irritation study. The animals were acclimatized for two weeks under standard laboratory conditions. All procedures were performed according to CPCSEA guidelines and approved by the Institutional Animal Ethics Committee (Regd. No: 1358/PO/Re/S/10/CPCSEA).
Extraction of Natural Dye
Shade-dried petals of Butea monosperma were macerated in distilled water for 3 days followed by reflux extraction for 3 hr. The extract was filtered, concentrated, and vaccum-dried at 60ºC to obtain a stable crystalline powder, which was stored in airtight containers until further use (Lakshmi et al., 2022). The aqueous extraction yielded 2.0% (w/w) dried extract, calculated based on the weight of the shade-dried flower petals powder.
Formulation of Lipstick
Lipstick formulations were prepared using standard reported procedures by melting and blending waxes, oils, and other excipients under controlled temperature (Sharma et al., 2021). The Butea monosperma extract was incorporated into the molten base, poured into moulds, and allowed to solidify. Among the three formulations prepared, Formula 3 showed the best pigment dispersion and physical uniformity without phase separation and was selected for further evaluation. The formulation composition is provided in Table 2, and the formulated lipsticks are shown in Figure 1.
| Name of the plant | Botanical name and Family | Part used | References |
|---|---|---|---|
| Dragon fruit Beetroot Turmeric | Hylocereus polyrhizus, Cactaceae Beta vulgaris, Amaranthaceae Curcuma longa, Zingeberaceae | Fruits Roots Rhizomes | Trupti et al., 2025 |
| Beetroot | Beta vulgaris, Amaranthaceae | Roots | Tejaswi et al., 2025 |
| Ajit et al., 2025 | |||
| Paper flower Beetroot saffron | B. spectabilis, Nyctaginaceae Beta vulgaris, Amaranthaceae Crocus sativus, Iridaceae | Flowers Roots Flowers | Sakthivel et al., 2025 |
| Rio red Strawberry Pomegranate Litchi Beetroot | Citrus × paradise, Rutaceae Fragaria x ananassa, Rosaceae Punica granatum, Lythraceae Litchi chinensis, Sapindaceae Beta vulgaris, Amaranthaceae | Fruits Fruits Fruits Fruits Roots | Anusha et al., 2025 |
| Beetroot Pomegranate | Beta vulgaris, Amaranthaceae Punica granatum, Lythraceae | Root Fruit peel | Bagang et al., 2025 |
| Beetroot Strawberry Tomato | Beta vulgaris, Amaranthaceae Fragaria x ananassa, Rosaceae L. lycopersicum, Solanaceae | Roots Fruits Fruits | Aditya et al., 2025 |
| Mangosteen | Garcinia mangostana, Clusiaceae | Peel | Amalia et al., 2025 |
| Purple cabbage | Brassica oleracea, Brassicaceae | Leaves | Hariharan et al., 2025 |
| Royal Poinciana | Delonix regia, Fabaceae | seeds | Shailesh et al., 2025 |
| Cockscomb | Celosia cristata, Amaranthaceae | Flowers | Pradeep et al., 2025 |
| Cactus | Opuntia dilleniid, Cactaceae | Fruits | Alburyhi et al., 2025 |
| Pomegranate | Punica granatum, Lythraceae | Fruit rind | Shravani et al., 2026 |
| Ingredients | Formula 1 (30 g) | Formula 2 (30 g) | Formula 3 (30 g) |
|---|---|---|---|
| Extract | 0.5 g | 0.5 g | 0.5 g |
| Bees wax | 5 g | 1 g | 0.9 g |
| Carnauba wax | 5 g | 1 g | 0.1 g |
| Ozakerite wax | - | 2 g | 0.6 g |
| Propylene glycol | 5 mL | 1 mL | 0.2 mL |
| Mineral oil | - | - | 0.35 mL |
| Cetyl alcohol | - | - | 0.25 gm |
| Isopropyl myristate | - | - | 0.1 mL |
| Lanolin | - | - | 0.25 gm |
| Castor oil | 6 mL | 3 mL | 1.5 mL |
| Liquid paraffin | 8 mL | - | |
| Coconut oil | - | 2 mL | - |
| Perfume, anti-oxidant and preservative | 2-3 drops | 2-3 drops | 2-3 drops |
Evaluation of Lipstick
Melting Point
The melting point was determined by the capillary tube method using a digital melting-point apparatus. A 10 mm lipstick column was filled into a capillary tube, and the analysis was performed in triplicate.
Breaking Point
The lipstick was subjected to increasing weight until breakage occurred. This test evaluated the mechanical strength and resistance to fracture.
Force of Application
The force required to apply the lipstick was assessed using a shadow graph balance. Lipstick was applied at a 45° angle on coarse brown paper to cover a 1 sq. inch area. The recorded pressure corresponded to the application force and firmness of the lipstick.
Spreadability
Spreadability was evaluated by applying the lipstick over a 3 cm length on a glass slide and visually assessing the smoothness and uniformity of the film. The formulation was graded as Excellent, Intermediate, or Unsatisfactory based on uniformity and fragmentation.
Surface Abnormalities
Formulations were inspected visually for defects such as crystal formation, sweating, fungal contamination, or surface irregularities.
Stability Studies
Stability studies were conducted under room temperature (24.0 ± 3.0ºC) and elevated temperature (40.0 ± 2.0ºC) conditions. Preliminary stability was assessed for 3 days, while long-term stability was evaluated for 60 days on days 3, 7, 15, 30, and 60. Parameters such as color, odor, appearance, melting point, and spreadability were monitored throughout the study.
pH Determination
As lipsticks are anhydrous, pH was determined from the aqueous fraction obtained by dissolving a small quantity of lipstick in ethanol followed by the addition of distilled water. The pH of the resulting extract was measured using a calibrated pH meter.
Skin Irritation Test
Three rabbits were divided into two test groups and one control group. Marketed lipstick was applied to one rabbit, and the formulated lipstick to another, while the third served as untreated control. The application site was monitored for visible signs of irritation compared with the control.
FTIR Analysis
FTIR spectra of the dried Butea monosperma flower extract and the lipstick formulation were recorded using a Bruker FTIR spectrophotometer (model Alpha 2-01054) equipped with Opus software. Spectra were obtained in the range of 400–4000 cm⁻¹ to assess chemical compatibility and functional group integrity (Sandhya et al., 2023).
Statistical analysis
All the experiments were performed in triplicate and the results were expressed as Mean ± S.D (n=3).
RESULTS
Organoleptic Properties
The formulated herbal lipstick exhibited a smooth, glossy, and uniform reddish-orange appearance characteristic of Butea monosperma extract, without cracks, air bubbles, or particle agglomeration. The fragrance remained pleasant throughout the study period.
Melting Point
The melting point of the lipstick was found to be 69.0±0.05ºC, indicating high thermal stability suitable for tropical climates. No batch-to-batch variation was observed.
Breaking Point
The breaking point values were within 8.0±0.7, demonstrating good mechanical strength. The lipstick remained intact under moderate pressure, confirming suitability for handling and application.
Force of Application
The lipstick required a moderate force of application, producing a uniform layer on the substrate. No streaks or resistance were observed, suggesting optimal firmness and glide properties.
Spreadability
The lipstick showed excellent spreadability, forming a consistent, smooth film without fragmentation or deformation. The film adhered well to the glass slide and exhibited uniform color distribution.
Surface Abnormalities
No surface defects such as sweating, crystallization, mold growth, or bloom formation were observed during the study. The surface remained smooth and stable.
Stability Studies
The lipstick remained stable under both room and elevated temperature conditions throughout the study period. No significant changes were observed in color, odor, appearance, melting point, or spreadability during short-term and long-term stability studies. The formulation also showed no signs of softening, phase separation, or surface defects, confirming its physical stability under normal storage conditions.
pH Determination
The pH of the hydroalcoholic extract of the lipstick was 6.8, falling within the acceptable dermal pH range. All the results for physicochemical parameters were given in Table 3.
| Parameter | Observation |
|---|---|
| Colour & Appearance | Smooth, uniform, reddish orange |
| Melting Point | 69.0±0.05°C |
| Breaking Point | 8.0±0.7 |
| Force of Application | Good |
| Spreadability | Excellent |
| Surface Abnormalities | None |
| Stability study | No bleeding or crystallization |
| pH | 6.8±0.01 |
| Skin Irritation | No irritation |
Skin Irritation Test
No signs of erythema, redness, edema, or irritation were observed in the rabbits treated with the formulated lipstick. The results were comparable to the control and marketed product. It was shown in Figure 2.
FTIR Analysis
FTIR analysis was performed to evaluate the chemical compatibility of Butea monosperma extract within the lipstick formulation. The extract exhibited broad peaks at 3845–3573 cm⁻¹ corresponding to O–H and N–H stretching vibrations of phenolic and flavonoid compounds, which were retained in the lipstick spectrum at 3661–3910 cm⁻¹, indicating preservation of major functional groups after formulation. Carbonyl stretching peaks shifted slightly from 1725–1691 cm⁻¹ in the extract to 1739 cm⁻¹ in the lipstick, suggesting weak interactions between phytoconstituents and excipients. Aromatic C=C vibrations observed at 1584–1512 cm⁻¹ in the extract were retained with minor shifts in the formulation. Characteristic C–O and C–N stretching bands were also observed in the fingerprint region (1241.67, 1172.39, 1043.59, and 991.21 cm⁻¹). Additional peaks at 2916 and 2848 cm⁻¹ corresponded to aliphatic C–H stretching from waxes and oils. Overall, the FTIR results confirmed the structural stability and compatibility of the extract within the lipstick matrix (Figure 3).
DISCUSSION
The formulated herbal lipstick containing Butea monosperma extract satisfied the essential quality parameters required for cosmetic application. During formulation optimization, three different compositions were prepared to identify the most suitable base for incorporating the water-soluble plant extract. Formula 1 exhibited uneven pigment distribution and phase separation due to poor compatibility between the aqueous extract and the predominantly oily base, a limitation similarly reported in previous herbal lipstick formulations. Formula 2 showed improved hardness because of increased wax content; however, pigment separation persisted, indicating inadequate dispersion of the hydrophilic extract. A stable and homogeneous formulation was achieved in Formula 3 by pre-dispersing the extract in propylene glycol before incorporation into the wax–oil matrix. Propylene glycol has been widely recognized as an effective co-solvent capable of improving compatibility between hydrophilic and lipophilic components in cosmetic systems (Barel et al., 2014). Therefore, Formula 3 was selected as the optimized formulation for further evaluation.
The optimized lipstick exhibited uniform coloration, smooth texture, and satisfactory aesthetic appearance, indicating efficient incorporation of the natural pigment within the wax–oil base. Similar observations have been reported for herbal lipsticks prepared using beetroot, hibiscus, and annatto pigments, where homogeneous pigment dispersion contributed to improved texture and consumer acceptability. The observed melting point falls within the acceptable range and demonstrated adequate thermal stability suitable for tropical climatic conditions and was found to be within acceptable limits specified by BIS standards for lipsticks (Bureau of Indian Standards, 1990). Mechanical properties such as breaking point and force of application also remained within acceptable limits, indicating a desirable balance between hardness and smooth application. Comparable findings have been reported previously, where excessive softness resulted in poor durability while highly rigid formulations reduced spreadability and consumer comfort (Agustina et al., 2020).
The formulation remained physically stable during both short-term and long-term storage under room and elevated temperature conditions. No sweating, crystallization, fungal growth, or texture changes were observed, indicating good resistance to environmental stress and strong compatibility among formulation excipients. Similar stability profiles have been described in earlier studies on herbal lipsticks containing natural pigments and wax–oil blends (Bhagwat et al., 2017). The pH is compatible and within the acceptable range for lip products and did not produce any irritation during animal testing. Previous studies have similarly reported pH values between 5.5 and 6.9 for herbal lipsticks formulated with botanical pigments, suggesting compatibility with the natural skin barrier (Lwin et al., 2020). Furthermore, the absence of erythema or edema confirmed the dermatological safety of the formulation.
FTIR analysis confirmed the chemical compatibility of Butea monosperma extract within the lipstick matrix. The retention of characteristic phenolic and flavonoid functional groups after formulation indicated the structural stability of the bioactive constituents. Similar FTIR findings have been reported for natural pigment-based cosmetic formulations, where preservation of functional groups suggested absence of chemical degradation during processing (Barel et al., 2014). Overall, the present findings validate Butea monosperma flower extract as a promising natural pigment for lipstick formulations with good stability, safety, and functional performance, supporting its potential as a sustainable alternative to synthetic colorants in cosmetic products.
Despite these encouraging findings, the present study has certain limitations. Future studies should include accelerated stability testing, microbiological quality evaluation, and clinical assessment in human volunteers to further establish the long-term safety and commercial applicability of the formulation.
CONCLUSION
The herbal lipstick formulated with Butea monosperma flower extract exhibited good physical stability, smooth application, and desirable aesthetic properties. The optimized formulation showed uniform color distribution, acceptable pH, and no signs of irritation, confirming its dermatological safety. Stability studies demonstrated resistance to temperature-induced changes, while FTIR analysis confirmed chemical compatibility between the extract and excipients. Overall, the findings support the potential of Butea monosperma as a safe and effective natural colorant for herbal lipstick formulations.