Beyond Organoleptic Characteristics: The Pharmacological Potential of Flavonoids and their Role in Leukocyte Migration and in L -Selectin and β2-Integrin Expression During Inflammation

Luteolin peracetate and gossypolone inhibit immune complex-mediated neutrophil activation in vitro and dermal-epidermal separation in an ex vivo model of epidermolysis bullosa acquisita

Introduction

Natural products have been shown to an important source of therapeutics for human disease. In this study, we aimed to identify natural compounds as potential therapeutics for epidermolysis bullosa acquisita (EBA), an autoimmune disease caused by autoantibodies to type VII collagen (COL7).

Methods

Utilizing an in vitro experimental system, we screened a natural product library composed of 800 pure compounds for their inhibitory effect on COL7-anti-COL7 IgG immune complex (IC)-mediated neutrophil activation and on neutrophil-mediated tissue damage.

Results

Three natural compounds, namely luteolin peracetate, gossypol, and gossypolone were capable in inhibiting the IC-induced neutrophil adhesion and oxygen burst in vitro. Furthermore, luteolin peracetate and gossypolone were able to inhibit the anti-COL7 IgG induced dermal-epidermal separation in an ex vivo model for EBA.

Discussion

In summary, this study demonstrates that luteolin peracetate and gossypolone are potential therapeutics for experimental EBA, which deserves further investigation.

Rutin (quercetin-3-rutinoside) modulates the hemostatic disturbances and redox imbalance induced by Bothrops jararaca snake venom in mice

Snakebites are a major Collective Health problem worldwide. In Brazil, Bothrops jararaca snake venom (BjV) evokes hemostatic disturbances, bleeding manifestations, and redox status imbalance. Specific antivenom therapy, although efficacious to revert most snakebite-induced manifestations, is incapable of treating secondary manifestations, such as oxidative/nitrosative stress. Searching for new complementary therapies that could attenuate physiological derangements triggered by envenomation, we elected to test quercetin-3-rutinoside (rutin) by its potential as both a potent antioxidant and a hemostasis modulatory compound. The activity of rutin was evaluated both on the biological activities of crude BjV in vitro, and in vivo by the ability of rutin (14.4 mg/kg b.w.) to modulate hematological, hemostatic and redox status markers altered by BjV injection (1.6 mg/kg b.w., s.c.) in mice. In vitro, rutin failed to inhibit BjV-induced platelet aggregation and biological activities of major BjV enzymes (metalloproteinases, phospholipases A2, serine proteases, and L-amino acid oxidases). On the other hand, rutin attenuated local hemorrhage, and the increase in reactive species, prevented the fall in RBC counts and fibrinogen levels, diminished tail bleeding and shortened prothrombin time (PT) evoked by envenomation. Furthermore, rutin reduced tissue factor (TF) activity and altered the protein expression of TF in liver, lungs, heart and skin. In conclusion, the disturbances in redox status and hemostatic system induced by B. jararaca envenomation were modulated by rutin, suggesting it has a great potential to be used as an ancillary therapeutic agent for snakebites.

Ethanolic extracts of babandotan leaves (Ageratum conyzoides L.) prevents inflammation and proteoglycan degradation by inhibiting TNF-α and MMP-9 on osteoarthritis rats induced by monosodium iodoacetate

OBJECTIVE

To analyze the effects of Ageratum conyzoides L. on the monosodium iodoacetate induced osteoarthritis rats.

METHODS

Thin layer chromatography was performed to analyze the constituents of the babandotan extract leaves. White male Sprague-Dawley rats used in this study were divided into 6 groups: normal control and negative control groups, both given 0.5% carboxymethyl cellulose; the positive control group that was given glucosamine and chondroitin suspension (486 mg/200 g B.W.); the 3 dose variation extract groups including dose 1, 2, and 3 that were given 40, 80, and 160 mg/200 g B.W. respectively on day 29 until 50. All the groups were induced with 0.05 mL monosodium iodoacetate (20 mg/mL) on day 1, except normal control induced by saline. Measurement of edema volume of rat knees was performed on day 0, 8, 15, 22, 29, 43, and 50. Hematology data was measured at day 1, 29 and 50. Serum was collected at day 50 to evaluate TNF-α and MMP-9 by ELISA. Cartilage histopathology was evaluated by staining with H&E and Safranin-O-fast green staining on day 50.

RESULTS

The babandotan leaves extract dose 2 (80 mg/200 g B.W.) and dose 3 (160 mg/200 g B.W.) could decrease the edema volume, increase the area and thickness of articular cartilage, and increase proteoglycan level. Particularly, dose 3 (160 mg/200 g B.W.) of extract babandotan leaves were able to significantly decrease the number of leukocytes, lymphocytes and udem volume, and decrease TNF alpha and MMP-9 levels.

CONCLUSIONS

Babandotan leaves extract can recover inflammation and cartilages degradation by inhibiting TNF-α in inflammation processes and MMP-9 in the collagenase reaction in the cartilages.

Eugenia aurata and Eugenia punicifolia HBK inhibit inflammatory response by reducing neutrophil adhesion, degranulation and NET release

BACKGROUND

Eugenia spp. are used in popular medicine in the treatment of pain, diabetes, intestinal disorders and cough. The aim of the work is to evaluate, ex vivo and in vivo, the anti-inflammatory activity of the hydroethanolic extracts of the leaves of Eugenia aurata (EA) and Eugenia punicifolia HBK (EP) upon neutrophils.

METHODS

Ex vivo, isolated human neutrophils were sensitized by Eugenia extracts (0.1-1000 μg/mL) and stimulated by PMA. In these conditions, different neutrophil activities related to inflammatory process were measured: adhesion, degranulation and NET release. Neutrophil viability and tumor line cells were monitored. In vivo, neutrophil influx was evaluated by peritonitis model performed in mice pretreated with different concentrations of Eugenia extracts. Phytochemical profile was assessed by mass spectrometry.

RESULTS

Ex vivo, EA and EP (1000 μg/mL) reduced cell adhesion and degranulation, respectively. NET release was inhibited by EA and EP. Anti-inflammatory activities occurred in the absence of cytotoxicity. In vivo, both EA as EP inhibited neutrophil migration. The phytochemical profile revealed that EA contains myricitrin, rutin, quinic acid and quercetin derivatives. EP presents gallic acid, quercetin derivatives, syringic acid, ellagic acid, monogalloyl-glucose, glycosyringic acid, mudanoside B, HHDP glucose isomer and digalloylglucose isomer. EA and EP inhibit neutrophil migration by different pathways.

CONCLUSION

Different chemical compositions may explain the anti-inflammatory effects described herein for EA and EP. Both extracts inhibit NET release but only EA reduces cell adhesion whereas EP decreases elastase secretion. This work contributes to the elucidation of cellular mechanisms related to the anti-inflammatory activity for leaves of E. aurata and E. punicifolia HBK.

Neutrophils and arthritis: Role in disease and pharmacological perspectives

The inflammatory response in the joint can induce an intense accumulation of leukocytes in the tissue that frequently results in severe local damage and loss of function. Neutrophils are essential cells to combat many pathogens, but their arsenal can contribute or aggravate articular inflammation. Here we summarized some aspects of neutrophil biology, their role in inflammation and indicated how the modulation of neutrophil functions could be useful for the treatment of different forms of arthritis.

Proinflammatory Pathways: The Modulation by Flavonoids

Inflammation is a natural, carefully orchestrated response of the organism to tissue damage, involving various signaling systems and the recruitment of inflammatory cells. These cells are stimulated to release a myriad of mediators that amplify the inflammatory response and recruit additional cells. These mediators present numerous redundancies of functions, allowing a broad and effective inflammatory response, but simultaneously make the understanding of inflammation pathways much difficult. The extent of the inflammatory response is usually self-limited, although it depends on the balance between the pro- and anti-inflammatory signals. When that equilibrium is dislocated, a more widespread inflammatory response may take place. Flavonoids have been shown to be possible alternatives to the traditionally molecules used as anti-inflammatory agents. In fact, the biological activities of flavonoids include the modulation of the diverse phases of inflammatory processes, from the gene transcription and expression to the inhibition of the enzymatic activities and the scavenging of the reactive species. In the present review, the inflammatory network is widely revised and the flavonoids' broad spectrum of action in many of the analyzed inflammatory pathways is revised. This kind of integrated revision is original in the field, providing the reader the simultaneous comprehension of the inflammatory process and the potential beneficial activities of flavonoids.