Flavonoid fraction of guava leaf extract attenuates lipopolysaccharide-induced inflammatory response via blocking of NF-κB signalling pathway in Labeo rohita macrophages.
Psidium guajava L. is a well-known traditional medicinal plant widely used in folk medicine. To explore the anti-inflammatory activity of the flavonoid fraction of guava leaf extract (FGLE), we investigated its ability to suppress the levels of inflammatory mediators elevated by lipopolysaccharide (LPS) in Labeo rohita head-kidney (HK) macrophages. HK macrophages of L. rohita were treated with LPS in the presence or absence of the FGLE. We examined the inhibitory effect of FGLE on LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production. The inhibitory effect of FGLE on nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were investigated by RT-PCR and western blot. The effect of FGLE on proinflammatory cytokines tumour necrosis factor alpha (TNF-α) or interleukin-1β (IL-1β) was also investigated by ELISA and RT-PCR. The phosphorylation of three mitogen activated protein kinases (MAPK) molecules ERK, JNK and p38 was analysed by western blot analysis. FGLE inhibited LPS-induced NO and PGE2 production. It also effectively inhibited TNF-α, IL-1β, IL-10, iNOS, and COX-2 production in a concentration-dependent manner. In addition, FGLE suppressed the mRNA expression levels of TNF-α and IL-1β in LPS-stimulated HK macrophages. RT-PCR and western blot analysis showed that FGLE decreased both the mRNA and protein expression levels of LPS-induced iNOS and COX-2 in HK macrophages. FGLE suppresses the phosphorylation of MAPK molecules in LPS-stimulated HK macrophages. FGLE also significantly inhibited LPS-induced NF-κB transcriptional activity. The molecular mechanism by which FGLE suppresses the expression of inflammatory mediators appears to involve the inhibition of NF-κB activation, through the suppression of LPS-induced IκB-α degradation. Together these results suggest that FGLE contains potential therapeutic agent(s), which regulate NF-κB activation, for the treatment of inflammatory conditions in L. rohita macrophages.
School of Life Sciences, Jawharlal Nehru University, New Delhi-110067 Delhi, India. Electronic address: shibsankar.iicb@gmail.com.
Shib Sankar
SS
Sen
Dept. of Biotechnology, Periyar Maniammai University, Thanjavur-613403, Tamil Nadu, India. Electronic address: drvsukumar@gmail.com.
V
V
Sukumaran
Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul-151742, South Korea. Electronic address: giribiotek@gmail.com.
Sib Sankar
SS
Giri
Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul-151742, South Korea. Electronic address: parksec@snu.ac.kr.
Se Chang
SC
Park
D000818:Animals; D003530:Cyprinidae; D005393:Fish Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D005419:Flavonoids / Q000494:pharmacology*; D060226:Head Kidney / Q000276:immunology; D007249:Inflammation / Q000382:microbiology / Q000662:veterinary*; D008070:Lipopolysaccharides / Q000502:physiology*; D008264:Macrophages / Q000276:immunology; D016328:NF-kappa B / Q000235:genetics* / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D031647:Psidium / Q000737:chemistry*; D015398:Signal Transduction
D005419:Flavonoids; D008070:Lipopolysaccharides; D016328:NF-kappa B; D010936:Plant Extracts
FGLE; Labeo rohita; Lipopolysaccharide; Macrophages; NF-κB signalling pathway