Analytical Identification Test and Characterization for Curcumin and Salicylic Acid

Taranjeet Kukreja¹, Swarnlata Saraf ^1*

¹University Institute of Pharmacy, Pt. Ravi Shankar Shukla University, Raipur - 492010, Chhattisgarh, India

^1*University Institute of Pharmacy, Dean, Faculty of Technology, Pt. Ravi Shankar Shukla University, Raipur - 492010, Chhattisgarh, India

Abstract.

The anti-inflammatory, antioxidant, anticancer, and antibacterial qualities, curcumin, which is produced from Curcuma longa (turmeric), shows great promise in dermatology, treating ailments like atopic dermatitis, chronic wounds, skin cancer, and infections. The goal of this study is to develop a more precise, easy, and cost-effective spectrophotometric approach for analysing Curcumin and Salicylic acid in various dosage forms with improved precision, accuracy, and sensitivity. The UV spectroscopic determination was performed with Methanol as the solvent at an absorption maximum of 424 nm and 288 nm respectively. Linearity over the concentration range in the UV spectroscopic approach. The linearity of both the drugs over the concentration range was found to be 1-10 g/ml using the UV spectroscopic technique, with a correlation coefficient of 0.9944 and 0.9966 respectively. As curcumin is coloured thus it was also identified in the digital photo calorimeter. The findings of the analyses were statistically and the recovery studies have confirmed this.

Keywords: Curcumin, digital photocolorimetry, pharmacopoeia, Salicylic Acid, UV spectroscopic technique.

Introduction

Traditional medicine, curcumin (CUR), a powerful polyphenol that makes up 2 to 8% of the components in Curcuma longa (turmeric), is praised for its therapeutic benefits(Vaughn et al., 2016). Vogel and Pelletier, who reported separating a "yellow colouring-matter" from the rhizomes of Curcuma longa (turmeric), made the initial identification of it approximately 200 years ago(Ryan et al., 2013). Additionally, it is a diferuloyl methane molecule [1,7-bis (4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione], which is one of the primary curcuminoids along with the commercially available demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC)(Surma et al., 2022). It is composed of two ferulic acid residues connected by a methylene bridge. Additionally, it demonstrates a wide range of beneficial benefits, including anti-inflammatory, antioxidant, anticancer, and antibacterial qualities.(Fig 1)(Kakkar et al., 2018).

Figure 1: Structure of Curcumin

The chemical molecule salicylic acid has the formula C7H6O3(Perlmutter et al., 2022). A substance with a harsh taste that is colourless (or white)(Bojić et al., 2015). It was first recognised and derived from the Latin salix, which means willow tree. Due to its analgesic, anti-inflammatory, and exfoliating qualities, salicylic acid (SA) has several uses in the treatment of rheumatic and skin conditions(Arif, 2015). Whereas for atopic dermatitis the studies show that in low concentration salicylic acid can be helpful in management of atopic dermatitis(Kukreja & Saraf, 2025a). Because of its lipophilic nature, suitable delivery methods are required to take advantage of these characteristics for various uses(Kukreja & Saraf, 2022a).(Fig 2)(Bojić et al., 2015).

Figure 2: Structure of Salicylic Acid

Mechanism of action of the drugs

Curcumin inhibits peroxide-induced DNA damage and lipid peroxidation by scavenging oxygen species like hydroxyl radical, superoxide anion, and singlet oxygen. Curcumin modulates several signalling molecules to produce strong anti-inflammatory and anti-carcinogenic effects(Saloki et al., 2023). Curcumin has been shown in vitro to inhibit protein kinases, c-Jun/AP-1 activation, prostaglandin biosynthesis, and the activity and expression of the enzyme cyclooxygenase (COX)-2, among other important components of cellular signal transduction pathways relevant to growth, differentiation, and malignant transformation(Kate et al., 2023).

When salicylic acid is applied to the skin's surface, it causes the epidermis' cells to shed more easily, keeps pores from becoming clogged, and makes space for the formation of new cells(Saloki et al., 2022). Salicylic acid inhibits the oxidation of uridine-5-diphosphoglucose (UDPG) both noncompetitively and competitively with NADH(Kukreja & Saraf, 2025b). Additionally, it competitively prevents uridine-5-phosphoglucuronic acid's glucuronyl group from being transferred to the phenolic acceptor(Castro et al., 2011).

Materials and methods

Experimental

Chemicals and reagents:

Throughout UV spectrophotometric technique, digital photocolorimetry, development and validation methanol was used.

Instrumentation

UV spectrophotometric technique was performed on a double beam UV-visible spectrophotometer (Shimadzu, model 1800) (Kukreja & Saraf, 2022b)having two matched quartz cells with a 1 cm light path for both the drug while curcumin was also identified in digital photo colorimetry.

Selection of solvent

For the analysis of Curcumin and salicylic acid, Methanol had been selected as the ideal solvent for spectrophotometry.

Standard stock solutions preparation

10 mg Curcumin  reference standard was accurately weighed and transferred to a 10 ml volumetric flask, where it was dissolved and diluted up to the mark using methanol to yield a stock solution with a strength of 500g/ml. Diluting 1 ml of stock solution to 5 ml with methanol yielded a 50 g/ml working standard solution.

Similarly 10 mg salicylic acid reference standard was accurately weighed and transferred to a 10 ml volumetric flask, where it was dissolved and diluted up to the mark using methanol to yield a stock solution with a strength of 500g/ml. Diluting 1 ml of stock solution to 5 ml with methanol yielded a 50 g/ml working standard solution.

Preparation of Sample stock solution

For analysis of the drug, 10mg of the drug curcumin was weighed and transferred to a 10ml volumetric flask and dissolved with methanol. The curcumin drug solution was diluted to get a final concentration of 10μg/ml. The absorbance of these solutions was measured at 424 nm. The amount of Curcumin was calculated using the calibration curve. Similarly done for salicylic acid whereas the absorbance of these solutions was measured at 288 nm.

Formula:

 %Purity=Sample absorbance / Standard absorbance X 100

1. Method validation

The method was validated according to the International Conference on Harmonization (ICH) Q2B guidelines 1996 for validation of analytical procedure to determine the linearity, limit of detection, accuracy and precision.

2. Linearity & Range

Under the experimental conditions, the calibration graphs of the absorbance versus Concentration were found to be linear over the range of 0.2-1.0μg/ml for the proposed method.

The statistical analysis of data obtained for estimation of Curcumin and salicylic acid is indicated methanol of accuracy for the proposed methods evidenced by the low values of standard deviation and coefficient of variation which was observed for curcumin both in UV Shimadzu 1800 and Photocolorimetry and for salicylic acid in UV Shimadzu 1800. The results are noted below:

Table 1: Curcumin and salicylic acid Linearity Data in UV Shimadzu 1800

Figure 3: Lambda max of curcumin obtained from UV Shimadzu 1800

Figure 4: Absorbance – Concentration graph of curcumin

Figure 5: Lambda max of salicylic acid obtained from UV Shimadzu 1800

Figure 6: Absorbance– Concentration graph of salicylic acid

Figure 7: Determination of Curcumin by digital photocolorimetry

 Table 2: Curcumin Linearity Data in Digital Photocolorimetry

Figure 8: Absorbance – Concentration graph of curcumin

Results and Discussion

The purpose of this study was to validate curcumin and salicylic acid using a UV-Spectrophotometric technique and digital photocolorimetry under optimal conditions. The validation parameters' results were found to be within acceptable limits. Within the concentration range of 1-10g/ml, of the drugs respectively followed linearity. The measured linearity range suited Beer-law Lambert's well, and the corresponding regression coefficient (r=0.9944 and r=0.9966) indicates a high degree of technique sensitivity, as shown in Table 1. The number of drugs detected and the findings of the analysis demonstrate that the percentage of the drugs found and the number of drugs found was in good accord.

Conclusion

UV-Spectrophotometer techniques produced equivalent results. The linearity of Curcumin and salicylic acid over the concentration range was found to be 1-10 g/ml using the UV spectroscopic technique, with a correlation coefficient of 0.9944 and 0.9966 respectively. The findings of the analyses were statistically and the recovery studies have been confirmed.

Acknowledgment

The authors are thankful to the department and University, Pt. Ravishankar Shukla University, Raipur, Chhattisgarh, India for practical support.

References

Arif, T. (2015). Salicylic acid as a peeling agent: A comprehensive review. Clinical, Cosmetic and Investigational Dermatology, 8, 455–461. https://doi.org/10.2147/CCID.S84765

Bojić, M., Sedgeman, C. A., Nagy, L. D., & Guengerich, F. P. (2015). Salicylic acid. European Journal of Pharmaceutical Sciences, 73, 49–56. https://doi.org/10.1016/J.EJPS.2015.03.015

Castro, G. A., Oliveira, C. A., Mahecha, G. A. B., & Ferreira, L. A. M. (2011). Comedolytic effect and reduced skin irritation of a new formulation of all-trans retinoic acid-loaded solid lipid nanoparticles for topical treatment of acne. Archives of Dermatological Research, 303(7), 513–520. https://doi.org/10.1007/S00403-011-1130-3

Kakkar, V., Kaur, I. P., Kaur, A. P., Saini, K., & Singh, K. K. (2018). Topical delivery of tetrahydrocurcumin lipid nanoparticles effectively inhibits skin inflammation: in vitro and in vivo study. Drug Development and Industrial Pharmacy, 44(10), 1701–1712. https://doi.org/10.1080/03639045.2018.1492607

Kate, V., Ushasree, R., Tharsanee, R. M., Kukreja, T., Saraf, S., & Varadharajan, B. (2023). GAN, CNN and ELM Based Breast Cancer Detection. 2023 2nd International Conference for Innovation in Technology, INOCON 2023. https://doi.org/10.1109/INOCON57975.2023.10101250

Kukreja, T., & Saraf, P. S. (2025a). DOE-Aided Development , Enhancement , and Description of Salicylic acid and Curcumin-Loaded Nanostructure lipid Carrier Gel and its Stability for the Effective Treatment of Atopic Dermatitis Journal of Chemical Health Risks. 15, 2046–2062.

Kukreja, T., & Saraf, S. (2022a). Formulation of Topical Itraconazole Nanostructured Lipid Carriers (Nlc) Gel for Onychomycosis. Journal of Ravishankar University, 35(2), 8–18. https://doi.org/10.52228/JRUB.2023-35-2-2

Kukreja, T., & Saraf, S. (2022b). UV Spectroscopy Analysis for Itraconazole. Journal of Ravishankar University, 35(2), 62–67. https://doi.org/10.52228/JRUB.2023-35-2-5

Kukreja, T., & Saraf, S. (2025b). Atopic Dermatitis: A Review on Nanocarrier-based Dermo-pharmaceutical Formulation for Inflammatory Effect. Current Indian Science, 03. https://doi.org/10.2174/012210299X358884250211064638’)

Perlmutter, J., Cogan, R., & Wiseman, M. C. (2022). Treatment of Atopic Dermatitis, Dermatophytes, and Syphilis by Indigenous Peoples Prior to 1850. Journal of Cutaneous Medicine and Surgery, 26(2), 198–200. https://doi.org/10.1177/12034754211058403

Ryan, J. L., Heckler, C. E., Ling, M., Katz, A., Williams, J. P., Pentland, A. P., & Morrow, G. R. (2013). Curcumin for radiation dermatitis: a randomized, double-blind, placebo-controlled clinical trial of thirty breast cancer patients. Radiation Research, 180(1), 34–43. https://doi.org/10.1667/RR3255.1

Saloki, A., Kukreja, T., & Saraf, S. (2022). ADVANCEMENTS IN DRUG DELIVERY FOR CHRONIC INFLAMMATORY DISEASES: RECENT APPROACHES AND STRATEGIES. Journal of Population Therapeutics and Clinical Pharmacology, 29(04), 376–385. https://doi.org/10.53555/JPTCP.V29I04.2515

Saloki, A., Kukreja, T., & Saraf, S. (2023). Advancements in Drug Delivery for Chronic Inflammatory Diseases: Recent Approaches and Strategies. Journal of Population and Therapeutics and Clinical Pharmacology, 29(04), 376–385. https://doi.org/10.53555/jptcp.v29i04.2515

Surma, S., Sahebkar, A., Urbański, J., Penson, P. E., & Banach, M. (2022). Curcumin - The Nutraceutical With Pleiotropic Effects? Which Cardiometabolic Subjects Might Benefit the Most? Frontiers in Nutrition, 9, 865497. https://doi.org/10.3389/fnut.2022.865497

Vaughn, A. R., Branum, A., & Sivamani, R. K. (2016). Effects of Turmeric (Curcuma longa) on Skin Health: A Systematic Review of the Clinical Evidence. Phytotherapy Research : PTR, 30(8), 1243–1264. https://doi.org/10.1002/PTR.5640