Abstract Liver’s contribution to innate immunity is eminent. However, uncontrolled inflammatory conditions predispose the liver to immune-mediated injury. Nigella sativa L. is traditionally implicated in infectious, inflammatory, metabolic and hepatorenal complications. This study aimed to evaluate the protective role of N. sativa seed extract (NSE) against concanavalin A (ConA)-induced acute immunological liver injury in mice. In vitro, NSE was subjected to quantitative phytochemical characterization and 1,1-diphenyl-2-picryhydrazyl (DPPH) analysis. In vivo, male Balb/c mice were pretreated with NSE (100, 200 and 400 mg/kg/day, p.o.) and pioglitazone (5 mg/kg/day, p.o.) for seven consecutive days. A single dose of ConA (12 mg/kg, i.v.) was injected and samples were collected for biochemical, histopathological and qRT-PCR analyses after 8 h of ConA injection. In vitro analysis showed considerable quantities of polyphenols and significant DPPH scavenging ability of NSE. In mice, ConA resulted in a significant (p<0.05) increase in liver injury markers (ALT, AST, ALP and TBil) and hepatic oxidative stress (SOD, CAT and MDA). Also, a substantial elevation of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) in liver tissues was noticed. Furthermore, ConA markedly downregulated PPARγ and upregulated JAK2 and STAT3 expressions. In addition, considerably decreased expressions of Bcl-2 and increased Bax and Caspase-9 were observed. NSE demonstrated hepatoprotective effect in a dose-dependent manner through attenuating liver injury markers, oxidative stress parameters, pro-inflammatory cytokines levels as well as liver inflammation and hepatocyte apoptosis via modulating PPARγ/JAK2/STAT3 and Bcl-2/Bax/Caspase-9 pathways. Conclusively, the antioxidative, anti-inflammatory and anti-apoptotic actions of NSE could protect against acute immunological liver injury. Livers Liver s eminent However immunemediated immune mediated L infectious complications N (NSE ConAinduced induced 1,1diphenyl2picryhydrazyl 11diphenyl2picryhydrazyl diphenylpicryhydrazyl 1,1 diphenyl 2 picryhydrazyl 1 (DPPH vivo Balbc Balb c 100, 100 (100 20 40 mgkgday mg kg day mg/kg/day p.o. po p o 5 ( days 12 (1 mgkg mg/kg i.v. iv i v biochemical qRTPCR qRT PCR injection p<0.05 p005 0 05 (p<0.05 ALT, ALT (ALT AST TBil SOD, SOD (SOD MDA. MDA . MDA) Also proinflammatory pro TNFα, TNFα TNF α, α (TNF-α IL1β ILβ IL 1β β IL6 6 IL-6 noticed Furthermore JAK STAT addition Bcl2 Bcl Bcl- Caspase9 Caspase 9 Caspase- observed dosedependent dependent parameters PPARγJAK2STAT3 PPARγJAKSTAT PPARγ/JAK2/STAT Bcl2/Bax/Caspase9 Bcl2BaxCaspase9 BclBaxCaspase 2/Bax/Caspase Bcl-2/Bax/Caspase- pathways Conclusively antioxidative antiinflammatory anti antiapoptotic apoptotic 1diphenyl2picryhydrazyl 11 1, 10 (10 4 p.o i.v p<0.0 p00 (p<0.0 IL- PPARγJAK PPARγJAK2STAT Bcl2/Bax/Caspase BaxCaspase Bcl2BaxCaspase 2BaxCaspase Bcl-2/Bax/Caspase p<0. p0 (p<0. p<0 (p<0 p< (p< (p

Abstract Ricinus communis L. and Withania somnifera L. have traditionally been used as analgesic and anti-inflammatory remedies. The current study was aimed to evaluate the in vitro antioxidant potential and anti-inflammatory activity of hydroalcoholic extract of R. communis leaves (RCE) and W. somnifera roots (WSE) in Wistar rats. Total phenolic and flavonoid contents were quantified and in vitro antioxidant activity of extracts was determined through DPPH* scavenging, superoxide anion scavenging and reducing power activities, while anti-inflammatory activity was observed by xylene-induced ear edema and paw edema induced by egg albumin and carrageenan. RCE and WSE demonstrated considerable antioxidant activity in DPPH* scavenging (IC50: 250.10 and 309.42 µg/mL), superoxide anion scavenging (IC50: 193.42 and 206.81 ug/mL), and reducing power (maximum absorbance: 1.47±0.01 O.D and 1.28±0.01 O.D at 500 ug/mL) activities, respectively, with high phenolic and flavonoid contents. Both extracts showed dose-dependent edema inhibition in inflammation models. A maximum ear edema inhibitions by RCE (51.49±2.54%) and WSE (49.28±1.90%) at 500 mg/kg were observed when compared to indomethacin (56.42±13.17%) in xylene-induced ear edema. RCE and WSE showed a maximum percentage of paw edema inhibitions of 46.62±8.98% and 43.00±12.44%, respectively as compared to chlorpheniramine (62.02±12.21%) after 4 h in the egg albumin model. In carrageenan-induced paw edema, RCE (72.88±13.79%) significantly inhibited paw edema in comparison to WSE (57.81±17.43%) against diclofenac (89.93±18.53%). Conclusively, both plants have shown plausible antioxidant and anti-inflammatory activities that might be due to high phenolic and flavonoid contents. Moreover, RCE demonstrated more promising effects than WSE.