Study On Antibacterial And Anti-inflammatory Activity Of 2,3-dioxoindoline

Objective: 2,3-dioxoindoline (ISA) is a kind of natural oceanic antibiotics from lobster while essential for lobster to survive . The study is to investigate the antibacterial, antifungal and anti-inflammatory activity of ISA.Methods:①The antibacterial effect of ISA against Escherichia coli and Staphylococcus aureus was observed with the agar diffusion assay. The tube dilution technique was used to determine the minimum inhibitory concentration (MIC) as well as to assess the minimal bactericidal concentration (MBC). The protective effect of ISA against the mortality of infectious mouse was observed by establishing the mouse infectious model.②The antifungal test of ISA was carried out by applying the fresh culture over the Sabouraud's agar plate. The antifungal MIC of ISA was determined using the tube dilution method.③The influence of ISA on the acute phase of inflammation was evaluated using the xylene-induced mouse ear inflammatory model and the agar-induced rat hind paw edema model.④The median lethal dose (LD50) of ISA was measured by the single-dose intragastric administration in mice while the chronic toxicity was surveyed by long-term intragastric administration in rats.Results:①ISA of 75 and 100 mg·ml^-1 exhibited evident antibacterial effect against Escherichia coli and Staphylococcus aureus. The mean MIC was 750μg/ml and the mean MBC was 3000μg/ml. The mean survival rate of mouse after 5 days in the ISA groups of 10,25 and 62.5 mg/kg was higher than that in the Sulfadiazine (SD) group.②ISA displayed distinguished inhibitive role to Trichophyton rubrum and mlcrosporum Lanosu (Bodin) Saboaraud. The antifungal MIC determined with the tube dilution method ranged from 0.016% to 0.500%. The skin reaction or self-sense symptom was absent in the patch test of ISA standard group. Observation of the clinical effect manifested that all clinical symptoms of tinea pedis disappeared.③ISA was effective to inhibit the mouse ear inflammation induced by xylene(P<0.001). ISA exhibited inhibitive effect on the agar-induced hind paw edema in rats(P<0.05).④The acute toxic LD50 in mouse was 1091±359mg·kg^-1 by intragastric administration. The long-term toxic test of six months in Wistar rats showed no notable abnormalty.Conclusion: The in vivo and in vitro tests demonstrate that the natural active substance ISA, possesses the antibacterial, antifungal and anti-inflammatory activity with a favourable safety range.