DESC:FIELD OF THE INVENTION
[1] The present invention relates to the field of cosmetic and dermatological formulations, specifically to topical skin care compositions in the form of a face serum. More particularly, the invention concerns a multifunctional cosmetic composition comprising green-synthesized zinc oxide nanoparticles stabilized with Clitoria ternatea (butterfly pea) extract, in combination with moisturizing, soothing, brightening, and UV-protective agents. The invention also relates to a sustainable method of manufacturing such a serum, offering enhanced skin hydration, barrier protection, antioxidant activity, anti-aging benefits, and broad-spectrum sun protection.

BACKGROUND AND PRIOR ART OF THE INVENTION
[2] Zinc oxide nanoparticles have been widely recognized for their multi-functionality in cosmetic formulations, particularly as broad-spectrum UV blockers and antimicrobial agents. Early patents such as WO2005104213A2 disclose the use of surface-treated ZnO nanoparticles in cosmetic products, emphasizing their photo protective efficacy. Other patents like US8961681B2 detail nanoparticle production techniques optimized for skin safety, highlighting the importance of controlled particle size and surface characteristics. However, these conventional methods often use chemical synthesis routes, which may involve toxic reagents and generate environmental concerns.

[3] To address sustainability and biocompatibility, the field has progressively shifted towards green synthesis methods leveraging plant extracts as reducing and stabilizing agents. Scientific studies and patents, for instance US10358356B1, demonstrate the successful synthesis of ZnO nanoparticles using lemongrass (Cymbopogon proximus) extracts, while research using sea lavender extract shows similar eco-friendly benefits. Recent investigations specifically with Clitoria ternatea flower extract confirm the feasibility of green synthesis for ZnO nanoparticles, utilizing the natural phytochemicals flavonoids, phenolics, and anthocyanins as both reduction agents and stabilizers. These biosynthesized nanoparticles exhibit enhanced biocompatibility, effective antimicrobial actions against pathogens like Escherichia coli, and favourable nanoscale morphology conducive to topical applications.

[4] Niacinamide, a well-established vitamin B3 derivative, is a cornerstone ingredient in dermatology and cosmetic formulations, widely recognized for its skin brightening, anti-inflammatory, and barrier-repair properties. Patents such as CA1074234A reveal niacinamide's ability to lighten skin by modulating melanin distribution, while others (e.g., CA2728165A1) explore its synergistic use with other actives for enhanced anti-aging effects. Despite its extensive use, prior art has not disclosed its incorporation specifically with green-synthesized ZnO nanoparticles stabilized by butterfly pea extract, nor the resulting multifunctional benefits therein.

[5] The butterfly pea extract itself possesses robust antioxidant and anti-inflammatory potential supported by ethno medicinal knowledge and modern research. Patents like JP4160964B2 and recent scientific literature underscore the extract's content of bioactive anthocyanin’s, flavonoids, and polyphenols, which contribute to skin health by combating oxidative stress and supporting elasticity. Yet, its combined application as a natural capping and reducing agent for nanoparticle synthesis integrated within a face serum formulation represents a novel and inventive use.

[6] Hydrating components such as propylene glycol, glycerine, sodium lactate, and hyaluronic acid form another integral aspect of state-of-the-art cosmetic serums. These ingredients enhance moisture retention, improve skin barrier function, and facilitate penetration of active molecules. Studies and patents like US20100008878A1 highlight the efficacy of moisture agents in optimizing skin hydration and active delivery, though typically without linking them to nanomaterial stabilization or green synthesis processes.

[7] While prior formulations may separately include UV blockers, antioxidants, brightening agents, and moisturizers, the present invention uniquely integrates green-synthesized ZnO nanoparticles using Clitoria ternatea extract concurrently as a functional bioactive and as a nanoparticle stabilizer. This dual role, coupled with the specific blend of niacinamide and hydration agents, achieves a synergistic effect with enhanced hydration, antioxidant capacity, anti-inflammatory action, and broad-spectrum UV protection, substantiated by detailed scientific characterization including FTIR, SEM, antioxidant assays, and SPF evaluation.

[8] Moreover, comprehensive safety evaluations demonstrating microbial compliance and absence of heavy metals such as lead and arsenic further underpin the practical viability and regulatory readiness of the serum composition. Such thorough testing and characterization exceed many existing cosmetic patents and studies that tend to lack integrated safety and functional data.

[9] In summary, the present invention distinguishes itself from the existing prior art by merging sustainable nanotechnology with multifunctional skincare formulation. The green synthesis of ZnO nanoparticles from butterfly pea extract in a scientifically validated serum containing moisturizing and skin-brightening agents provides an innovative solution that aligns with contemporary consumer and regulatory demands for natural, effective, and safe cosmetic products. This represents a significant advancement over previous inventions by uniting ecological manufacturing techniques with enhanced skin benefits in a single novel composition and manufacturing process.

OBJECTIVES OF INVENTION
[10] To develop a multifunctional face serum composition incorporating green-synthesized zinc oxide nanoparticles produced using Clitoria ternatea (butterfly pea) flower extract as both a natural reducing and stabilizing agent, thereby providing an eco-friendly, biocompatible, and sustainable alternative to conventionally synthesized nanoparticles.

[11] To formulate a stable topical cosmetic product that delivers synergistic skin benefits—including hydration, brightening, antioxidant protection, anti-inflammatory action, anti-aging effects, and broad-spectrum UV protection—through the combined action of zinc oxide nanoparticles, niacinamide, moisturizing humectants, and bioactive phytochemicals from butterfly pea extract.

[12] To provide a reproducible and scalable manufacturing process for the serum composition that preserves the integrity and efficacy of active ingredients, ensures safety by eliminating harmful contaminants, and meets cosmetic regulatory standards for commercial application.

SUMMARY OF THE INVENTION
[13] The present invention relates to a novel, multifunctional face serum composition and its method of manufacture, featuring zinc oxide nanoparticles synthesized through a green, eco-friendly process using Clitoria ternatea (butterfly pea) flower extract as both the reducing and stabilizing agent. This botanical-mediated approach not only eliminates reliance on hazardous chemical reductants but also introduces the bioactive flavonoids, phenolics, and anthocyanins inherent in butterfly pea extract directly into the final product. The synthesis yields quasi-spherical ZnO nanoparticles of 30–80 nm size, uniformly distributed and exhibiting high stability. The nanoparticles serve as powerful UV filters and antimicrobial agents, while the butterfly pea extract provides strong antioxidant and anti-inflammatory benefits, creating a dual-function ingredient that is both active and functional in stabilizing the nanomaterial.

[14] The composition uniquely combines these green-synthesized ZnO nanoparticles with a carefully balanced blend of skin-beneficial components, including niacinamide, allantoin, propylene glycol, glycerin, sodium lactate, hyaluronic acid, phenoxyethanol, fragrance, and distilled water. Each ingredient is selected for its proven dermatological efficacy: niacinamide enhances skin brightening and barrier function, allantoin soothes and promotes healing, humectants (propylene glycol, glycerin, sodium lactate, hyaluronic acid) deliver deep, sustained hydration, while the ZnO nanoparticles and butterfly pea actives provide broad-spectrum UVA/UVB protection and antioxidant defense. This multi-ingredient synergy addresses multiple skin concerns simultaneously — dryness, pigmentation, photo aging, inflammation — within a single, stable formulation.

[15] The method of manufacture involves dispersing ZnO nanoparticles in distilled water, sequentially adding moisturizing and active agents, incorporating the butterfly pea extract, fragrance, and preservative, followed by precise pH adjustment to 5.3 using citric acid. Hyaluronic acid is hydrated into the mixture, and the formulation is filtered before packaging. This process preserves the structural integrity and functionality of bioactives while ensuring homogeneity and reproducibility on a commercial scale.

[16] Scientific characterization confirms the presence and stability of active ingredients within the serum. FTIR spectroscopy reveals functional group signatures from both the butterfly pea extract and cosmetic actives, alongside defined Zn–O stretching peaks verifying nanoparticle inclusion. SEM imaging demonstrates consistent nanoparticle morphology and size distribution. The antioxidant capacity of the serum is exceptionally high, showing 95.6% free radical scavenging activity in DPPH assays — a marked improvement over the butterfly pea extract alone (84.21%), indicating synergistic performance with other actives. SPF testing according to the Mansur method yields a value of 33.33, placing the serum in the high-protection category against UVA and UVB radiation.

[17] Safety and regulatory compliance have been rigorously validated. Microbial analysis confirms that total viable counts, yeast and mold levels are far below permissible limits, with the complete absence of Escherichia coli and Pseudomonas aeruginosa . Heavy metal testing by ICP-MS detects no lead or arsenic, ensuring the serum is free from toxic contaminants. The mild skin-friendly pH further affirms its suitability for daily topical application.

[18] In summary, the invention delivers a scientifically validated, environmentally sustainable, and multifunctional skincare product that innovatively integrates green nanotechnology with dermatologist-recommended cosmetic actives. By using Clitoria ternatea both as a core bioactive and as a green nanomaterial synthesis medium, the serum bridges the domains of natural product science, cosmetic formulation, and safety-standard compliance. This unique combination of sustainable synthesis, multifunctional efficacy, and robust characterization sets the invention apart from existing cosmetic formulations, offering an advanced solution for comprehensive skin care with potent hydration, brightening, anti-aging, antioxidant, and photoprotective benefits.

BRIEF DESCRIPTION OF THE DRAWING
[19] The invention has other advantages and features which will be more readily apparent from the following detailed description of the invention and the appended claims, when taken in conjunction with the accompanying drawings, in:

[20] Figure 1: depicts the SEM image of the face serum composition.
[21] Figure 2: depicts the FTIR image of ZnONP.
[22] Figure 3: depicts the FTIR image of Butterfly pea extract.
[23] Figure 4: depicts the FTIR image of Face serum composition.

DETAILED DESCRIPTION OF THE INVENTION
[24] While the invention has been disclosed concerning certain embodiments, it will be understood by those skilled in the art that various changes may be made, and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention without departing from its scope.

[25] Throughout the specification and claims, the following terms take the meanings explicitly associated herein unless the context clearly dictates otherwise.

[26] The meaning of "a", "an", and "the" include plural references. The meaning of "in" includes "in" and "on." Referring to the drawings, like numbers indicate like parts throughout the views. Additionally, a reference to the singular includes a reference to the plural unless otherwise stated or inconsistent with the disclosure herein.

[27] The figures and protocols have been represented where appropriate by conventional representations in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description.

[28] The present invention provides a multifunctional face serum composition and its method of manufacture, wherein the serum incorporates zinc oxide nanoparticles synthesized via a green, plant-mediated process using Clitoria ternatea (butterfly pea) flower extract as both a natural reducing and stabilizing agent. This eco-friendly nanotechnology approach replaces conventional chemical synthesis methods that often involve toxic reagents, thus significantly reducing environmental impact while enhancing product safety and biocompatibility. The butterfly pea extract, rich in anthocyanins, flavonoids, phenolics, and polyphenols, not only facilitates nanoparticle formation through its phytochemical profile but also contributes valuable antioxidant, anti-inflammatory, and photo-protective functions to the final cosmetic product.

[29] A face serum composition is prepared comprising, in percentage by weight: allantoin (0.1–1%), propylene glycol (10–20%), sodium lactate (3–8%), glycerin (5–15%), niacinamide (2–7%), phenoxyethanol (0.5–1.5%), hyaluronic acid (0.1–0.5%), butterfly pea extract (Clitoria ternatea) (15–25%), fragrance (0.5–1.5%), distilled water (35–50%), and zinc oxide nanoparticles in an effective concentration of about 1–5%, the said nanoparticles having an average particle size of 30–80 nm, predominantly quasi spherical in morphology.

[30] The method of preparing the face serum composition comprises the following steps:
i. Weigh the required amount of green synthesized zinc oxide nanoparticles (1–5%) and disperse them in distilled water (35–50%) under controlled mixing to obtain a uniform suspension
ii. Mix allantoin (0.1–1%) with glycerin (5–15%) and propylene glycol (10–20%) until homogeneous, then add sodium lactate (3–8%) to the blend to form a Humectant–Active Blend
iii. Add the humectant–active blend from step (ii) into the ZnO–water dispersion prepared in step (i) with gentle stirring
iv. Incorporate niacinamide (2–7%) and mix thoroughly using a magnetic stirrer or homogenizer until fully dissolved
v. Introduce butterfly pea extract (15–25%) into the mixture and stir until uniform
vi. Add fragrance (0.5–1.5%) and phenoxyethanol (0.5–1.5%) to the mixture and blend evenly.
vii. Measure the initial pH (approximately 8.0) and adjust to about 5.3 by slowly adding 2 M citric acid under constant mixing to ensure skin friendly acidity and stability of actives
viii. Sprinkle hyaluronic acid (0.1–0.5%) into the adjusted mixture and allow sufficient time for complete hydration
ix. Filter the serum to remove any particulates and ensure a smooth, homogenous liquid
x. Transfer the finished serum into suitable bottles or containers under hygienic conditions for storage and commercial distribution

[31] The zinc oxide nanoparticles thus produced have an average particle size of 30–80 nanometres, predominantly quasi spherical in morphology, and are uniformly dispersed within the serum matrix. Their nanoscale dimensions’ increase surface area and enhance light scattering properties, thereby improving UVA and UVB defence while supporting skin adhesion and even distribution upon application.

[32] The synergistic functional design of the serum is achieved through a thoughtful combination of ingredients with complementary activities. Allantoin functions as a skin protectant and healing agent, improving cell regeneration and soothing irritation. Propylene glycol, glycerin, and sodium lactate act as humectants to retain moisture, restore the skin's natural moisturizing factor, and enhance penetration of other actives. Niacinamide works synergistically with zinc oxide to reduce inflammation, regulate pigmentation, improve skin barrier strength, and modulate sebum production, making the formulation suitable for acne-prone and sensitive skin. Hyaluronic acid, with its ability to retain up to 1000 times its weight in water, provides deep hydration and plumping effects. The butterfly pea extract imparts potent antioxidant capacity, neutralizing reactive oxygen species and protecting against photoaging, while also assisting ZnO nanoparticle stabilization at the molecular level.

[33] The invention has been extensively characterized to verify its functional attributes. FTIR spectroscopy confirms the integration of ZnO nanoparticles through characteristic Zn–O stretching peaks between 403–410 cm?¹ and the preservation of functional groups from hyaluronic acid, niacinamide, and butterfly pea polyphenols, including hydroxyl, carbonyl, and amide linkages. SEM imaging demonstrates quasi-spherical nanoparticles with smooth surfaces and minimal agglomeration, confirming stabilization by the phytochemicals of Clitoria ternatea. The particle size distribution and morphology are ideal for topical application, enabling even coverage and effective UV shielding.

[34] Functional assays reveal superior antioxidant activity: the face serum shows a 95.6% inhibition in DPPH radical scavenging assays, compared to 84.21% for the butterfly pea extract alone, evidencing synergistic enhancement by the combined ingredients. SPF evaluation via the Mansur equation yields a rating of 33.33, placing the serum within the high-protection category for both UVA and UVB radiation. This high photoprotective capacity arises from the combined effects of the ZnO nanoparticles’ physical blocking and the UV-absorption characteristics of polyphenols from butterfly pea.

[35] The serum also meets stringent safety standards, having passed microbial analysis with total viable count at 530 CFU/g, yeast and mold count below 10 CFU/g, and absence of E. coli and Pseudomonas aeruginosa, in full compliance with IS 14648:2011. Heavy metal testing via ICP-MS confirmed that lead and arsenic were undetectable (<0.1 mg/kg), ensuring the absence of toxic contaminants. The final formulation’s mild pH (5.14) aligns perfectly with the physiological range for facial skin, minimizing irritation risk.

[36] Overall, the invention delivers an advanced skincare product that harmoniously merges sustainable nanotechnology with proven cosmetic actives into a stable, safe, and multifunctional serum. It addresses multiple dermatological needs—hydration, brightening, antioxidation, anti-aging, anti-inflammatory benefits, and UV protection—in a single eco-friendly formulation. This dual-function utilization of Clitoria ternatea extract as both nanoparticle stabilizer and cosmetic bioactive is a distinguishing feature, underscoring the inventive step and industrial applicability of the product.

EXAMPLE
[37] The following example illustrates a preferred embodiment of the invention, but should not be construed as limiting its scope in any way.

Example 1: SEM Analysis:
[38] The surface morphology and particle size of the biosynthesized ZnO nanoparticles were analysed using Scanning Electron Microscopy (SEM). Samples were prepared by drop-coating a dilute nanoparticle suspension onto conductive stubs, followed by gold sputter-coating to enhance conductivity. SEM imaging was carried out at suitable accelerating voltages to capture high-resolution micrographs. Multiple magnifications were used to assess particle morphology, size distribution, surface texture, and possible agglomeration.

Results:
[39] SEM analysis depicted in figure 1 reveals that the ZnO nanoparticles were predominantly quasi-spherical to slightly elliptical in shape, with an estimated average particle size in the range of 30–80?nm. The particles exhibited a relatively uniform distribution with moderate agglomeration, a characteristic feature of green-synthesized nanoparticles due to phytochemical-mediated stabilization. The surfaces appeared granular and rough, with no sharp crystalline facets, suggesting a semi-amorphous nature and effective organic capping by compounds from Clitoria ternatea extract. Moderate porosity and consistent surface texture indicated controlled nucleation and growth during synthesis. The morphology and particle size distribution confirmed that the plant extract functioned as a dual agent, serving both as a reducer and as a natural stabilizer or capping agent. The high surface-to-volume ratio of the nanoparticles is advantageous for cosmetic serum applications, enabling improved skin penetration, UV protection, and antimicrobial activity. These morphological characteristics demonstrate that the green synthesis method is reproducible, scalable, and sustainable compared to conventional chemical or physical methods.

Example 2: FTIR analysis:
[40] The ZnO nanoparticles, butterfly pea extract, and face serum samples were prepared according to standard protocols. Solid samples were finely ground and mixed with KBr to form pellets, while liquid or gel samples were analysed directly using an ATR crystal. FTIR spectra were recorded in the range of 4000–400 cm?¹ with a resolution of 4 cm?¹, averaging multiple scans to reduce noise. Peak positions were identified and compared with literature values to assign the corresponding functional groups. The spectra of ZnO nanoparticles, butterfly pea extract, and face serum were examined individually to confirm synthesis, identify bioactive compounds, and determine retained or newly formed bonds. Comparative analysis was then performed to identify shared and unique peaks, thereby assessing the presence of key active components and the interactions between ZnO and plant-derived compounds in the serum formulation.

Result:
i. ZnO Nanoparticles:
[41] The ZnO nanoparticles depicted in Figure 2 showed a strong absorption band between 400–600?cm?¹, corresponding to Zn–O stretching vibrations. A distinct absorption peak was observed around 406?cm?¹, confirming the presence of ZnO nanoparticles. The most significant absorption occurred in the low wavenumber region (403–410?cm?¹), indicating ZnO formation. No prominent peaks were detected in the higher wavenumber region, suggesting minimal organic residue from the butterfly pea extract. These results confirm the successful synthesis of ZnO nanoparticles. The absence of peaks arising from organic molecules suggests that calcination or purification was effective. The Zn–O stretching mode at 406?cm?¹ was consistent with reported literature values.

ii. Butterfly Pea Extract:
[42] The FTIR spectrum of the butterfly pea extract depicted in Figure 3 exhibited a broad absorption band in the range 3360–3258?cm?¹ due to O–H stretching vibrations of hydroxyl groups, phenols, and flavonoids. Peaks were also observed at 2935–2859?cm?¹, corresponding to C–H stretching of alkanes and lipids, and at 1636?cm?¹, representing C=C stretching vibrations of aromatic rings and flavonoids. In the region 989–402?cm?¹, various bending vibrations of aromatic and heterocyclic compounds were detected. The overall spectrum indicated the presence of hydroxyl, amine, carbonyl, and ether functional groups, consistent with flavonoids, phenolics, and possible glycosides.

iii. Face Serum:
[43] The FTIR spectrum of the face serum depicted in Figure 4 displayed a broad O–H/N–H stretching band around 3321?cm?¹, associated with hyaluronic acid, niacinamide, and phenolic compounds from the butterfly pea extract. Peaks at 2978–2943?cm?¹ corresponded to C–H stretching, while a broad band at 2530?cm?¹ suggested strong hydrogen bonding in hyaluronic acid. Bands between 2241–2203?cm?¹ indicated C=N or C=C stretching (likely from niacinamide). Weak overtone or combination bands were observed in the 2176–2100?cm?¹ region. A carbonyl peak at 1643?cm?¹ and C–N amide vibrations at 1458–1338?cm?¹ were also present, along with C–O stretching bands at 1245–1041?cm?¹. ZnO stretching vibrations appeared between 922–475?cm?¹. These findings confirm that the serum retained hydroxyl, amine, carbonyl, and ether functional groups from hyaluronic acid, niacinamide, and flavonoids, while incorporating ZnO for UV protection.

[44] Both the extract and serum spectra showed a ~3300?cm?¹ band, confirming the presence of phenolics, flavonoids, and amines. C=O stretching (~1640?cm?¹) occurred in both, indicating ketones, amides, or carbonyl groups. C–O stretching (1040–1240?cm?¹) suggested glycosides, polysaccharides, or esters in both samples. The serum spectrum uniquely displayed ZnO peaks (922–475?cm?¹), absent in the extract, while the extract exhibited a broader O–H band (~3843?cm?¹) due to higher flavonoid content. Additional peaks at 1458–1338?cm?¹ in the serum were linked to niacinamide (C–N and amide vibrations). The FTIR analysis confirmed that the face serum successfully retained active functional groups from the butterfly pea extract while incorporating ZnO and niacinamide.

Example 3: Microbial analysis:
[45] The face serum was evaluated for pH, total microbial count, yeast and mold count, and the presence of specified pathogens in accordance with IS 14648:2011 standards.

Result:
[46] The serum exhibited a pH of 5.14, which falls within the optimal skin compatible range of 4.5–6.5. The total microbial count was 530 CFU/g, well below the permissible limit of 1000 CFU/g, while yeast and mold counts were <10 CFU/g, indicating negligible fungal presence, as shown in Table 1. Pathogenic bacteria, including Escherichia coli and Pseudomonas aeruginosa, were not detected. These findings confirm that the serum meets all relevant microbiological and safety specifications.

Parameter Test Result Specification Limit
pH 5.14 -
Total Microbial Count 530 CFU/g NMT 1000 CFU/g
Yeast & Mold Count <10 CFU/g NMT 1000 CFU/g
Pseudomonas aeruginosa Absent/g Absent/g
Escherichia coli Absent/g Absent/g

Table 1: Microbial analysis of Serum

Example 4: Heavy Metal analysis:
[47] The face serum sample was analysed for heavy metal content (Lead and Arsenic) using ICPMS (Inductively Coupled Plasma Mass Spectrometry). The sample was prepared and digested appropriately before instrumental analysis to achieve a Limit of Quantification (LOQ) of 0.1 mg/kg for each metal.

Result
[48] The results showed that all tested heavy metals including lead, mercury, cadmium, copper, and arsenic were present in the serum within the acceptable limits specified by the standards, as shown in Table 2. This confirms the serum’s compliance with safety requirements for heavy metal content, ensuring it is safe for cosmetic use and free from the risk of heavy metal contamination. The heavy metal analysis indicated that the levels of toxic metals were either undetectable or below the permissible thresholds, in accordance with safety regulations. These findings further validate the face serum’s safety profile, complementing the results of the microbial analysis. These results confirmed that the formulation was safe for topical use and supported its eligibility for patent filing and commercialization.

Parameter Result Limit of Quantification (LOQ) Analytical Method
Lead (Pb) Not Detected 0.1 mg/kg ICPMS (IFL/QCSP G/009)
Arsenic (As) Not Detected 0.1 mg/kg ICPMS (IFL/QCSP G/009)

Table 2: Heavy Metal analysis of Serum

Example 5: Antioxidant and SPF Analysis:
[49] The antioxidant activity of the butterfly pea extract and face serum was evaluated using the DPPH free radical scavenging assay. Samples were prepared and tested following standard protocols, with percent inhibition calculated to quantify antioxidant capacity.

[50] For the Sun Protection Factor (SPF) analysis, the serum’s absorbance was measured using a UV-Vis spectrophotometer across the UVB spectrum (wavelengths 290–320 nm, at 5 nm intervals). The erythemal effect (EE) and solar intensity (I) values for each wavelength were sourced from Sayre et al. SPF was calculated according to the Mansur equation:

SPF=CF×?(EE(?)×I(?)×Abs(?))

[51] where CF (correction factor) was set to 10. Absorbance values (Abs(?)) were taken from measurements of the serum sample dissolved in ethanol or methanol.

Results
[52] The butterfly pea extract demonstrated 84.21% inhibition in the DPPH assay, indicating high antioxidant activity. The face serum exhibited a higher inhibition percentage of 95.6%, likely attributable to synergistic effects from its components, including butterfly pea extract, niacinamide, and ZnO nanoparticles. Both samples reflect potent antioxidant properties, with the serum’s enhanced activity suggesting effective ingredient interaction.

[53] SPF calculation for the serum further clearly depicted in Table 3 yielded a value of 33.33, based on measured absorbance and standardized EE and I value. This places the serum in the “high protection” category (SPF 30–50), indicating effective UVA and UVB protection. The strong UV protection is attributed to the antioxidant polyphenols and flavonoids in the butterfly pea extract that absorb UVB radiation, coupled with ZnO nanoparticles acting as physical blockers against UVA and UVB rays. This combination confers broad-spectrum photo protection alongside antioxidant benefits, supporting the serum’s suitability for skin care applications targeting UV protection and oxidative stress mitigation.

Wavelength (nm) EE(?) × I(?) Abs(?) EE(?) × I(?) × Abs(?)
290 0.015 3.913 0.058695
295 0.0817 3.827 0.309987
300 0.2874 3.953 1.134511
305 0.3278 3.428 1.120956
310 0.1864 2.732 0.508152
315 0.0839 2.063 0.171229
320 0.018 1.655 0.02979

Table 3: SPF calculation for the serum

ADVANTAGES OF THE INVENTION
? The formulation utilises green-synthesised zinc oxide nanoparticles prepared with Clitoria ternatea (butterfly pea) extract acting as both a reducing and stabilising agent, eliminating toxic chemical reagents and enhancing biocompatibility and sustainability.
? The butterfly pea extract serves a dual function as a synthesis medium for the ZnO nanoparticles and as a high concentration active ingredient (15–25% w/w) in the final serum, delivering potent antioxidant, anti-inflammatory, and UV absorbing benefits.
? The ZnO nanoparticles have a controlled average particle size of 30–80 nm and quasi spherical morphology, optimising UV scattering, skin adherence, and antimicrobial properties while maintaining a smooth, non gritty texture.
? The combination of humectants (glycerin, propylene glycol, sodium lactate, hyaluronic acid), skin barrier enhancers (niacinamide, allantoin), and actives (butterfly pea extract, ZnO NPs) provides hydration, UV protection, antioxidant defence, anti-ageing, and soothing effects in a single product.
? The serum achieves SPF 33.33 (high protection category), exhibits 95.6% DPPH antioxidant inhibition, passes IS 14648:2011 microbial safety standards, and has no detectable lead or arsenic — ensuring both efficacy and safety for consumer use.
? The defined stepwise manufacturing method — including controlled nanoparticle dispersion, sequential ingredient blending, and pH adjustment to ~5.3 — ensures ingredient stability, preserves bioactive potency, and is reproducible for commercial scale production.

Dated this day of 19th August 2025
,CLAIMS:We claim:
1. A face serum composition comprising, in percentage by weight:
a) 0.1–1% of allantoin;
b) 10–20% of propylene glycol;
c) 3–8% of sodium lactate;
d) 5–15% of glycerine;
e) 2–7%, of niacinamide;
f) 0.5–1.5% of phenoxyethanol;
g) 0.1–0.5% of hyaluronic acid;
h) 15–25% of butterfly pea (Clitoria ternatea) extract;
i) 0.5–1.5% of fragrance;
j) 35–50% of distilled water; and
k) 1–5% of zinc oxide nanoparticles
wherein the zinc oxide nanoparticles are synthesized using Clitoria ternatea extract as both a reducing and stabilizing agent,
wherein the nanoparticles having an average particle size of 30–80 nm with quasi spherical morphology.

3. The composition of claim 1, wherein the zinc oxide nanoparticles are free from detectable lead and arsenic.

4. The composition of claim 1, wherein the composition exhibits an SPF value of at least 30, preferably about 33.3.

5. The composition of claim 1, wherein the composition exhibits DPPH radical scavenging activity of at least 90% inhibition.

6. The composition of claim 1, wherein the zinc oxide nanoparticles have a surface morphology with moderate porosity to enhance skin adhesion and UV scattering.

7. A method of manufacturing a face serum composition comprising the steps of:
i. dispersing green-synthesized zinc oxide nanoparticles in distilled water, wherein the zinc oxide nanoparticles are synthesized using Clitoria ternatea extract as a reducing and stabilizing agent, and have an average particle size of 30–80 nm with predominantly quasi-spherical morphology, said nanoparticles being present at 1–5% by weight based on the total composition;
ii. preparing a humectant-active blend by mixing allantoin (0.1–1% w/w), glycerin (5–15% w/w), and propylene glycol (10–20% w/w) until homogeneous, then adding sodium lactate (3–8% w/w) to the blend;
iii. combining the humectant-active blend with the zinc oxide nanoparticle suspension under controlled mixing to obtain a uniform mixture;
iv. adding niacinamide (2–7% w/w) to the mixture and mixing thoroughly until fully dissolved;
v. incorporating butterfly pea (Clitoria ternatea) extract (15–25% w/w) into the mixture and stirring until uniform;
vi. adding fragrance (0.5–1.5% w/w) and phenoxyethanol (0.5–1.5% w/w) to the mixture, and blending evenly;
vii. measuring the pH of the mixture (approximately 8.0) and adjusting to about 5.3 by slow addition of 2 M citric acid under constant stirring to ensure skin-friendly acidity and stability of the actives;
viii. sprinkling hyaluronic acid (0.1–0.5% w/w) into the pH-adjusted mixture and allowing sufficient time for complete hydration;
ix. filtering the serum to remove any particulates and ensure a smooth, homogeneous liquid; and
x. transferring the finished serum into suitable bottles or containers under hygienic conditions for storage and commercial distribution.

Dated this day of 19th August 2025