Antibacterial and antiviral evaluation of sulfonoquinovosyldiacylglyceride: a glycolipid isolated from Azadirachta indica leaves

• Published in: Letters in applied microbiology Vol. 58; no. 2; pp. 184 - 189
• Main Authors: Bharitkar, Y.P, Bathini, S, Ojha, D, Ghosh, S, Mukherjee, H, Kuotsu, K, Chattopadhyay, D, Mondal, N.B
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell 01-02-2014; Oxford University Press
• Subjects: Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; antimicrobial; antimicrobial properties; antiviral; Antiviral Agents - chemistry; Antiviral Agents - isolation & purification; Antiviral Agents - pharmacology; Azadirachta - chemistry; Azadirachta indica; bacteria; Biological and medical sciences; Cytokines - metabolism; drugs; Enterobacteriaceae - drug effects; enzyme-linked immunosorbent assay; Escherichia coli; Fundamental and applied biological sciences. Psychology; Glycolipids - chemistry; Glycolipids - isolation & purification; Glycolipids - pharmacology; Gram-Negative Bacteria - drug effects; Gram-Negative Bacteria - growth & development; herpes simplex; Herpes simplex virus 1; Herpes simplex virus 2; Herpesvirus 1, Human - drug effects; Herpesvirus 2, Human - drug effects; interleukin-1; leaves; macrophages; Microbial Sensitivity Tests; Microbiology; minimum inhibitory concentration; phytotherapy; Plant Leaves - chemistry; Pseudomonas aeruginosa - drug effects; Pseudomonas aeruginosa - growth & development; Salmonella typhi; Shigella dysenteriae; Simplexvirus - drug effects; solubility; Staphylococcus aureus - drug effects; Staphylococcus aureus - growth & development; Sulfonoquinovosyl‐diacylglyceride; tumor necrosis factor-alpha; Vibrio cholerae; Vibrio cholerae - drug effects; Vibrio cholerae - growth & development; Viral Plaque Assay; viruses; Evaluation; antimicrobial; Applied microbiology; Plant leaf; Meliaceae; Antimicrobial agent; Sulfonoquinovosyl-diacylglyceride; Glycolipid; Dicotyledones; Angiospermae; Antiviral; Spermatophyta; Antibacterial agent; Azadirachta indica; antiviral
• ISSN: 0266-8254; 1472-765X
• DOI: 10.1111/lam.12174

Assessment of antibacterial as well as antiherpes virus activity of sulfonoquinovosyldiacylglyceride (SQDG), a glycolipid, isolated from the leaves of Azadirachta indica has been described. Antimicrobial activity was evaluated against Gram‐positive, Gram‐negative bacteria and herpes simplex virus. SQDG showed significant inhibitory activity against Salmonella typhi and two isolates of Shigella dysenteriae with MIC values 32 μg ml⁻¹, while three isolates of Salm. typhi, Escherichia coli and Vibrio cholerae were inhibited at 64 μg ml⁻¹ and have shown zone diameter ranging from 6·2 to 12·3 mm. The growth kinetics study of SQDG on Salm. typhi and Sh. dysenteriae revealed that the growths were completely inhibited at their MIC values within 24 h of exposure. Interestingly, SQDG inhibits herpes simplex virus (HSV) type 1 and 2 with the EC₅₀ of 9·1 and 8·5 μg ml⁻¹, compared with acyclovir (2·2 and 2·8 μg ml⁻¹ against HSV‐1 and HSV‐2). The selectivity index (SI) was found to be 12·4 against HSV‐1 and 13·41 with HSV‐2. Furthermore, the expression of proinflammatory cytokines of HSV‐infected and SQDG‐treated macrophages using ELISA kit revealed that SQDG significantly downregulated the production of TNF‐α, IL‐1β, IL‐12 and IL‐6. SIGNIFICANCE AND IMPACT OF THE STUDY: The water‐soluble metabolite sulfonoquinovosyldiacylglyceride (SQDG) isolated from Azadirachta indica (Neem) possess significant antibacterial as well as anti‐HSV activity. The efficacies as well as the solubility factor of SQDG substantiate a greater attention for its use as phytotherapeutic drug for controlling microbial infections as most consumers have better acceptance of phytomedicines than synthetic drugs.