This study is undertaken to investigate the effects of naringenin on doxorubicin- (Dox) induced nephrotoxicity in Wistar rats. Dox 10 mg/kg body weight was administered intraperitoneally once and naringenin 50 and 100 mg/kg body weight was administered orally daily for 21 d. Dox-induced oxidative stress lead to steep elevation in blood urea nitrogen (BUN), creatinine, lactate dehydrogenase (LDH), and kidney injury molecule-1 (KIM-1), compared to control, treatment with naringenin preserved kidney functions. With Dox treatment significant decrease in antioxidant enzymes with increase in malondialdehyde (MDA) compared to control was observed. Naringenin treatment reversed these values compared to Dox in kidney tissue. Dox treatment showed increased tissue nitric oxide levels naringenin treatment decreased nitric oxide (NO) in kidney tissue. Furthermore, Dox-induced inflammatory burst as indicated by up-regulation of nuclear factor-κB (NF-κB), tumour necrosis factor-α (TNF-α) tissue levels and prostaglandin-E2 (PGE-2). All such events were normalised back to normal by naringenin treatment.

The goal of this study was to assess the pharmacological effects of black tea (Camellia sinensis var. assamica) water extract on human kinin-forming enzymes in vitro. Tea is a highly consumed beverage in the world. Factor XII (FXII, Hageman factor)-independent- and -dependent activation of prekallikrein to kallikrein leads to the liberation of bradykinin (BK) from high-molecular-weight kininogen (HK). The excessive BK production causes vascular endothelial and nonvascular smooth muscle cell permeability, leading to angioedema. The prevalence of angiotensin-converting enzyme inhibitor (ACEI)-induced angioedema appears to be through BK. Both histamine and BK are potent inflammatory mediators. However, the treatments for histamine-mediated angioedema are unsuitable for BK-mediated angioedema. We hypothesized that long-term consumption of tea would reduce bradykinin-dependent processes within the systemic and pulmonary vasculature, independent of the anti-inflammatory actions of polyphenols. A purified fraction of the black tea water extract inhibited both kallikrein and activated FXII. The black tea water extracts inhibited factor XII-induced cell migration and inhibited the production of kallikrein on the endothelial cell line. We compared the inhibitory effects of the black tea water extract and twenty-three well-known anti-inflammatory medicinal herbs, in inhibiting both kallikrein and FXII. Surprisingly, arjunglucoside II specifically inhibited the activated factor XII (FXIIa), but not the kallikrein and the activated factor XI. Taken together, the black tea water extract exerts its anti-inflammatory effects, in part, by inhibiting kallikrein and activated FXII, which are part of the plasma kallikrein–kinin system (KKS), and by decreasing BK production. The inhibition of kallikrein and activated FXII represents a unique polyphenol-independent anti-inflammatory mechanism of action for the black tea.

Background: This study aimed to evaluate the effects of selected phosphodiesterase-4 inhibitors (PDE-4 inhibitors)—roflumilast, ibudilast, and crisaborole—on the activity of blood coagulation factor XII (FXII). In the intrinsic coagulation pathway, FXII is known to initiate the kallikrein–kinin system (KKS), causing an increase in the system expression, which ultimately leads to inflammation and coagulation states. Additionally, the activation of KKS downstream effectors leads to inflammation. Inflammation signaling was found to be initiated when the bradykinin (BK) protein binds to its B2 receptor because of the FXII-dependent pathway activation. BK abnormalities can cause a critical condition, hereditary angioedema (HAE), which is characterized by recurring serious swelling. While it is considered unnecessary for hemostasis, FXII is an important enzyme for pathogenic thrombosis. Because of this special characteristic, FXII is a desirable therapeutic target. Our hypothesis is to identify the inhibitory effects of roflumilast, ibudilast, and crisaborole on the activated FXII and to reveal their beneficial impacts in the reduction of the pathogenesis of FXII-related conditions, HAE, and thrombosis. In a current study, we presented the inhibitory effect of tested drugs on the main target activated factor XII (FXIIa) as well as two other plasma protease enzymes included in the target pathway, plasma kallikrein and FXIa. Methods: To achieve our aim, in vitro chromogenic enzymatic assays were utilized to assess the inhibitory effects of these drugs by monitoring the amount of para-nitroaniline (pNA) chromophore released from the substrate of FXIIa, FXIa, or plasma kallikrein. Results: Our study findings exhibited that among assessed PDE-4 inhibitor drugs, roflumilast at micromolar concentrations significantly inhibited FXIIa in a dose-dependent manner. The FXIIa was clearly suppressed by roflumilast, but not the other related KKS members, plasma kallikrein, or the activated factor XI. On the other hand, ibudilast and crisaborole showed no inhibitory effects on the activities of all enzymes. Conclusions: Overall, roflumilast could be used as a lead compound for developing a novel multifunctional therapeutic drug used for the prevention of HAE or thrombotic disorders.