Awareness on antioxidants and its significance in human healthcare has increased many folds in recent time. Increased demand requisite on welcoming newer and alternative resources for natural antioxidants. Seaweed associated pigmented bacteria screened for its antioxidant potentials reveals 55.5% of the organisms were able to synthesize antioxidant compounds. DPPH assay showed 20% of the organisms to reach a antioxidant zone of 1 cm and 8.3% of the strains more than 3 cm. Pseudomonas koreensis (JX915782) a Sargassum associated yellowish brown pigmented bacteria have better activity than known commercial antioxidant butylated hydroxytoluene (BHT) against DPPH scavenging. Serratia rubidaea (JX915783), an associate of Ulva sp. and Pseudomonas argentinensis (JX915781) an epiphyte of Chaetomorpha media , were also contributed significantly towards ABTS (7.2% ± 0.03 to 15.2 ± 0.09%; 1.8% ± 0.01 to 15.7 ± 0.22%) and FRAP (1.81 ± 0.01 to 9.35 ± 0.98; 7.97 ± 0.12 to 18.70 ± 1.84 μg/mL of AsA Eq.) respectively. 16S rRNA gene sequence analysis revealed bacteria that have higher antioxidant activity belongs to a bacterial class Gammaproteobacteria. Statistical analysis of phenolic contents in relation with other parameters like DPPH, ABTS, reducing power and FRAP are well correlated (p < 0.05). Results obtained from the current study inferred that the seaweed associated pigmented bacteria have enormous potential on antioxidant compounds and need to be extracted in a larger way for clinical applications.

Bacterial strain Vibrio sp. (PIGB 184) isolated from water samples of the Arabian Sea and identified through 16S rRNA demonstrated the production of pigmentary antioxidants with higher ABTS activities 90.9 ± 0.42 % in comparison with the standard commercial pigmented antioxidant, quercetin 88.8 ± 1.4 %. Antioxidative metabolites of this strain substantially inhibit the lipid peroxidation (LPO) reactions tested in sheep liver and brain. The antioxidant compounds produced by the Vibrio sp. (PIGB 184), analysed by GC-MS, reveals that it is composed mostly of phenol, 2,4-bis(1,1-dimethylethyl) and pyrrolo[1,2-a]pyrazine-1,4-dione,hexahydro-3-(2-methylpropyl). The interrelationship assessed between LPO and the phenolic compounds showed significant correlation with anti-LPO properties (R (2) = 0.9698 to 0.9861). These compounds are responsible for obstruction of harmful radical associated biochemical reactions in biological systems. Pigmented metabolites also tested for attributive biological properties against pathogenic bacteria showed prominent inhibition towards Gram-positive organisms (31.25 to 62.5 μg ml(-1)). From this study, it may be suggested that the marine bacterium PIGB 184 could be used as a potential bio-resource for antioxidants and needs to be worked out for mass production.

ÖZETAmaç: Oksidatif stres inflamatuvar barsak hastalıklarının patogenezinde önemli rol oynar. Bu çalışmada, antioksidan L-karnitinin deneysel kolitte, kolonda da sentez edilen paraoksonaz 1 enzim aktivitelerine ve oksidatif duruma etkisini inceledik. Gereç ve Yöntem: Wistar albino dişi sıçanlar kontrol, kolit, ön tedavi ve tedavi olmak üzere rastgele dört gruba ayrıldı. Kolit oluşturmak için kolit, tedavi ve ön tedavi gruplarına tek doz 1 mL asetik asit (%4) intrarektal olarak uygulandı. Ön tedavi grubuna kolit oluşturulmadan 1 saat önce, tedavi grubuna ise kolit oluşturulduktan 24 saat sonra 500 mg/kg L-karnitin tek doz halinde intraperitoneal olarak verildi. Tüm gruplar intrarektal uygulamadan 48 saat sonra sakrifiye edildi. Kolit varlığı histopatolojik olarak gösterildi. Serumda paraoksonaz, arilesteraz ve laktonaz aktiviteleri, total oksidan ve antioksidan durum, malondialdehit ve total sialik asit ölçüldü. Oksidatif stres indeksi formülden hesaplandı. Bulgular: Asetik asitle kolit oluşturulan grupta serum malondialdehit, total sialik asit, total oksidan durum ve oksidatif stres indeksi anlamlı olarak artarken, paraoksonaz, arilesteraz ve laktonaz aktiviteleri ve total antioksidan durum anlamlı olarak azaldı. L-Karnitin malondialdehit, total sialik asit, total oksidan durum ve oksidatif stres indeksinde anlamlı bir azalmaya yol açarken, sadece tedavi grubunun serum arilesteraz ve laktonaz aktivitelerinde anlamlı bir artışa yol açtı. Sonuç: Asetik asitle oluşturulan deneysel kolitte L-karnitin, arilesteraz ve laktonaz aktivitelerini arttırıcı, oksidatif stresi azaltıcı bir etkiye sahiptir. Bu nedenle L-karnitin, inflamatuvar barsak hastalıklarının tedavisinde yararlı olabilir. Anahtar Sözcükler: Deneysel kolit, L-karnitin, paraoksonaz, arilesteraz, laktonaz, oksidatif stres, malondialdehit, total sialik asit Çıkar Çatışması: Yazarlar arasında çıkar çatışması yoktur. ABSTRACT Aim:Oxidative stress plays an important role in the pathogenesis of inflammatory bowel disease. We investigated antioxidant L-carnitine effect on activities of paraoxonase 1 enzyme which is also synthesized in colon and oxidative status in experimental colitis. Material and Methods: Wistar albino female rats were divided into four groups randomly: control, colitis, pre-treatment and treatment groups. To induce colitis, single dose of 1 mL acetic acid (%4) was given intrarectally to colitis, pre-treatment and treatment groups. Single dose of 500 mg/kg L-carnitine was given intraperitoneally 1 hour before inducing colitis to pre-treatment group and 24 hours after inducing colitis to treatment group. All groups were sacrificied 48 hours after intrarectally administration. Existence of colitis was confirmed by histopathological changes. Paraoxonase, arylesterase and lactonase activities, total oxidant and antioxidant status, malondialdehyde, and total sialic acid were measured in serum. Oxidative stress index was calculated from the formula. Results: While serum malondialdehyde, total sialic acid, total oxidant status and oxidative stress ind...

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