Evaluation of The Antimicrobial, Anti-Inflammatory And Antioxidant Activities of Citrus Leaf Extract Incorporated Into Sodium Alginate Gel: An in Vitro Study

Abstract

Background

Citrus limon (L.) Osbeck contains various bioactive constituents that may contribute to antimicrobial and antioxidant activities. Incorporating plant extracts into polymeric formulations such as sodium alginate may provide a potential approach for developing plant-based formulations. However, the biological activity of the incorporated extract requires experimental evaluation. The present study aimed to evaluate the antimicrobial, antioxidant, and preliminary anti-inflammatory activities of Citrus limon leaf extract incorporated into a sodium alginate formulation.

Materials and Methods

Fresh C. limon leaves were processed using sterile distilled water and incorporated into a sodium alginate formulation. The antimicrobial activity was evaluated using the agar well diffusion method against Acinetobacter baumannii and Streptococcus mutans. Antioxidant activity was assessed using the DPPH radical scavenging assay at concentrations of 20, 40, 60, 80, and 100 µg/mL, with ascorbic acid as the reference standard. The anti-inflammatory evaluation was performed using an albumin denaturation assay, with diclofenac sodium as the reference standard. The results were presented descriptively based on the available recorded values.

Results

The formulation produced inhibition zones of 21 mm against A. baumannii and 17 mm against S. mutans, compared with 25 mm and 20 mm for the respective positive controls. The recorded antioxidant response of the formulation increased from 14.43 at 20 µg/mL to 75.71 at 100 µg/mL, while the corresponding values for ascorbic acid ranged from 21.09 to 89.65. In the albumin assay, the recorded response of the formulation increased from 14.27 to 73.71 across the tested concentration range, whereas diclofenac sodium showed values ranging from 22.94 to 87.33. The formulation showed lower recorded responses than the respective reference standards in both comparative assays.

Conclusion

The sodium alginate formulation containing C. limon leaf extract demonstrated preliminary antibacterial activity against the tested organisms and concentration-related increases in the recorded antioxidant and albumin assay responses. However, the absence of replicate information, variability measures, and inferential statistical analysis limits the strength of the findings. Further studies involving standardized assay protocols, appropriate controls, phytochemical characterization, formulation stability assessment, and safety evaluation are required to establish the reproducibility and potential applications of the formulation.