Unlocking the antimicrobial potential of Kappaphycus alvarezii: A groundbreaking perspective towards solvent-dependent extraction and diffusion dynamics

Ayyangar, Eyyunni Pardha Saradhi; Neha, Koneru; Gudivada, Mani

doi:10.21608/mid.2025.374849.2684

	Unlocking the antimicrobial potential of Kappaphycus alvarezii: A groundbreaking perspective towards solvent-dependent extraction and diffusion dynamics
Microbes and Infectious Diseases
Articles in Press, Accepted Manuscript, Available Online from 17 June 2025
Document Type: Original Article
DOI: 10.21608/mid.2025.374849.2684
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Authors
Eyyunni Pardha Saradhi Ayyangar ¹; Koneru Neha ²; Mani Gudivada ³
¹MSc Student, Department of Zoology, Andhra University, Visakhapatnam, Andhra Pradesh, India.
²Research Scholar, Department of Zoology, Andhra University, Visakhapatnam, Andhra Pradesh, India.
³Professor, Department of Zoology, Andhra University, Visakhapatnam, Andhra Pradesh, India
Abstract
Background: The growing threat of antibiotic resistance has intensified the search for natural antimicrobial agents. This study evaluates the antibacterial potential of Kappaphycus alvarezii, a marine red alga, with emphasis on the influence of solvent choice and compound diffusion on its bioactivity. Methods: Antibacterial activity was assessed using extracts of Kappaphycus alvarezii prepared with dimethyl sulfoxide (DMSO) as the extraction solvent. The Kirby-Bauer disc diffusion method was employed to test activity against selected Gram-negative and Gram-positive bacterial strains commonly associated with infections in immunocompromised individuals. Results: The extract demonstrated selective antibacterial activity against Gram-negative bacteria. Escherichia coli showed dose-dependent inhibition, with zones of 6 mm at 125 µg/disc and 10 mm at 1000 µg/disc. Serratia marcescens exhibited inhibition zones ranging from 4 mm (250 µg/disc) to 8.3 mm (1000 µg/disc), while Pseudomonas aeruginosa showed limited inhibition (9.3 mm at 1000 µg/disc). No inhibition was observed against Gram-positive bacteria. DMSO control was included to validate solvent-specific effects. Conclusions: Kappaphycus alvarezii exhibits promising selective antibacterial activity against Gram-negative bacteria. These findings highlight the influence of solvent polarity and diffusion dynamics on antimicrobial performance. Optimizing extraction strategies may enhance the therapeutic potential of marine algae as sustainable antimicrobial sources.
Keywords
Keywords: antibacterial activity; Kappaphycus alvarezii; Gram-positive; Gram-negative; DMSO


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