Algicidal effects of aqueous leaf extracts of neem (Azadirachta indica) on Scenedesmus quadricauda (Turp.) de Brébission

Abstract

The application of synthetic algaecides for the control of algae produces by-products that are sometimes toxic to the environment. There is a need for natural and cheap alternatives to synthetic algaecides. In the present study, we investigated the potential of aqueous crude extract of Azadirachta indica to inhibit the growth of Scenedesmus quadricauda. Phytochemical screening of the extract revealed the presence of groups of bioactive compounds that are capable of inhibiting microalgal growth. Chlorophyll a concentration, dry weight production and cell density of microalga decreased with increasing crude extract concentration. After three days of exposure, the 1000 mg/L extract concentration resulted in complete growth inhibition and cell lysis. Furthermore, the ability of S. quadricauda to form multi-celled coenobial structures was compromised in a concentration dependent manner. In general, catalase and peroxidase activities of the microalga were upregulated with increasing extract concentration. These results imply that aqueous neem extract may provide a cheap and ecofriendly alternative for the control of microalgae in aquatic ecosystems.

Combined Effect of Isolated Bacteriophage and Neem Extract on Isolated Multiple Drug-Resistant Pathogenic Escherichia coli E1 From Well Water

“…The phenolic compounds, along with nimbin, are the most prominent components of neem extract, and they have high antimicrobial properties. According to Alzohairy, 43 , 44 the nimbin of neem exhibits a broad range of killing efficiency against a different class of bacteria. As a result, the extract was tested for antibacterial efficacy against the E. coli E1.…”

Effects of extraction temperature on phytoconstituents of leaf extracts of Azadirachta indica and its antiparasitic efficacy against Argulus sp.

“…Other than tannin, each phytoconstituents was obtained by Kumari et al (2019) in the aqueous dried neem leaf extract. Furthermore, Chia et al (2016) observed all estimated phytoconstituents in aqueous dried leaf extract, except for saponin and tannin which could be attributed to variations in the method of extraction.…”

A Sustainable Approach to Study on Antimicrobial and Mosquito Repellency Properties of Silk Fabric Dyed with Neem (Azadirachta indica) Leaves Extractions

“…The test results revealed that extracts from neem leaves showed better activity against Gram-negative bacteria. It could be said that the microbial activity of extracted solution will be dependent on the presence of active bio components and the concentration of extracted solution [51,52]. S. aureus.…”

“…The test results revealed that extracts from neem leaves showed better activity against Gram-negative bacteria. It could be said that the microbial activity of extracted solution will be dependent on the presence of active bio components and the concentration of extracted solution [51,52]. Antimicrobial analysis of dyed samples on petri plates after agar diffusion test determined that samples dyed with concentrated dye bath solution with the extracted solution had better inhibition zone against Gram-negative bacteria (Figure 11) and Gram-positive bacteria (Figure 12).…”

“…Again, SE1B2 and SE2B2 showed antibacterial activity in terms of diameter of inhibition zone against bacteria that was 0.3 mm and 0.1 mm, respectively against E. coli and 0.15 mm and 0.05 mm against S. aureus. Samples SE3B2 and SE4B2 had no antimicrobial activ- that the microbial activity of extracted solution will be dependent on the presen bio components and the concentration of extracted solution [51,52]. Antimicrobial analysis of dyed samples on petri plates after agar diffusion mined that samples dyed with concentrated dye bath solution with the extract had better inhibition zone against Gram-negative bacteria (Figure 11) and Gra bacteria (Figure 12).…”