Evaluation of the Antibacterial Activity and Toxicity of C-Phycocyanin and Cellular Extracts from Westiellopsis sp., a Filamentous Freshwater Cyanobacterium
Mithun Kumar Rathod
Department of Zoology, Tara Government College (Autonomous), Sangareddy, India.
B. Sujatha
Department of Sericulture, Sri Krishnadevaraya University, Anantapuramu (A.P), India.
Mandapati Venkatesh Prasad
Department of Sericulture, Sri Krishnadevaraya University, Anantapuramu (A.P), India.
Dara Hadassah Eunice
Sri Konda Laxman Telangana Horticultural University, Mulugu, India.
Bharath M P
Department of Entomology, School of Agriculture, Kaveri University, Gowraram, Wargal Mandal, Siddipet, India.
Prathyusha Kantheti
Department of Apparel and Textile Science, College of Community Science, Odisha University of Agriculture and Technology, India.
Mallikarjun S. Yadawade
Department of Zoology, Shri. Mallikarjun Ashram Trust’s, Shivanand College, Kagwad- 591 223, Belagavi, Karnataka, India.
Md Shadab Alam *
College of Fisheries, OUAT, Rangeilunda760007, Odisha, India.
*Author to whom correspondence should be addressed.
Abstract
This study employed the paper disc diffusion method to evaluate the antibacterial efficacy and toxicity profile of culture filtrate and C-phycocyanin extracted from the filamentous freshwater cyanobacterium Westiellopsis sp. against three pathogenic bacteria: Bacillus subtilis (Gram-positive), Pseudomonas sp. (Gram-negative), and Xanthomonas sp. (Gram-negative), resulting in inhibition zones ranging from 1.3 ± 0.2 mm to 13.2 ± 0.5 mm. Toxicity was assessed using a silkworm (Bombyx mori) bioassay. Larvae fed with C-phycocyanin extracts from different strains showed increased total body weight (65.1-102.6% increase) and silk gland weight (209.1-240.9% increase) compared to controls, with no observed adverse effects. Statistical analysis confirmed these increases were highly significant (p < 0.001). These results demonstrate that both the crude culture filtrate and the refined pigment possess notable antibacterial properties and exhibit a favorable safety profile in an invertebrate model. The dual activity of these natural extracts supports their potential application as alternative antibacterial agents in agricultural and medicinal contexts. Future studies should focus on comprehensive molecular characterization of active compounds, determination of minimum inhibitory concentrations (MIC), and expanded toxicity testing in mammalian models to confirm clinical viability.
Keywords: Antibacterial, cyanobacteria, freshwater, phycocyanin, silkworm, westiellopsis sp