The diterpene from Sphagneticola trilobata (L.) Pruski, kaurenoic acid, reduces lipopolysaccharide-induced peritonitis and pain in mice

Synthesis and Antibacterial Activity of Polyalthic Acid Analogs

Polyalthic acid (PA) is a diterpene found in copaiba oil. As a continuation of our work with PA, we synthesized PA analogs and investigated their antibacterial effects on preformed biofilms of Staphylococcus epidermidis and determined the minimal inhibitory concentration (MIC) of the best analogs against planktonic bacterial cells. There was no difference in activity between the amides 2a and 2b and their corresponding amines 3a and 3b regarding their ability to eradicate biofilm. PA analogs 2a and 3a were able to significantly eradicate the preformed biofilm of S. epidermidis and were active against all the Gram-positive bacteria tested (Enterococcus faecalis, Enterococcus faecium, S. epidermidis, Staphylococcus aureus), with different MIC depending on the microorganism. Therefore, PA analogs 2a and 3a are of interest for further in vitro and in vivo testing to develop formulations for antibiotic drugs against Gram-positive bacteria.

Kaurenoic Acid Reduces Ongoing Chronic Constriction Injury-Induced Neuropathic Pain: Nitric Oxide Silencing of Dorsal Root Ganglia Neurons

Kaurenoic acid (KA) is a diterpene extracted from Sphagneticola trilobata (L.) Pruski. KA presents analgesic properties. However, the analgesic activity and mechanisms of action of KA in neuropathic pain have not been investigated so far; thus, we addressed these points in the present study. A mouse model of neuropathic pain was induced by chronic constriction injury (CCI) of the sciatic nerve. Acute (at the 7th-day post-CCI surgery) and prolonged (from 7–14th days post-CCI surgery) KA post-treatment inhibited CCI-induced mechanical hyperalgesia at all evaluated time points, as per the electronic version of von Frey filaments. The underlying mechanism of KA was dependent on activating the NO/cGMP/PKG/ATP-sensitive potassium channel signaling pathway since L-NAME, ODQ, KT5823, and glibenclamide abolished KA analgesia. KA reduced the activation of primary afferent sensory neurons, as observed by a reduction in CCI-triggered colocalization of pNF-κB and NeuN in DRG neurons. KA treatment also increased the expression of neuronal nitric oxide synthase (nNOS) at the protein level as well as the intracellular levels of NO in DRG neurons. Therefore, our results provide evidence that KA inhibits CCI neuropathic pain by activating a neuronal analgesic mechanism that depends on nNOS production of NO to silence the nociceptive signaling that generates analgesia.

In Silico Computational Studies of Bioactive Secondary Metabolites from Wedelia trilobata against Anti-Apoptotic B-Cell Lymphoma-2 (Bcl-2) Protein Associated with Cancer Cell Survival and Resistance

In the present study, the binding affinity of 52 bioactive secondary metabolites from Wedelia trilobata towards the anti-apoptotic B-cell lymphoma-2 (Bcl-2) protein (PDB: 2W3L) structure was identified by using in silico molecular docking and molecular dynamics simulation. The molecular docking results demonstrated that the binding energies of docked compounds with Bcl-2 protein ranged from -5.3 kcal/mol to -10.1 kcal/mol. However, the lowest binding energy (-10.1 kcal/mol) was offered by Friedelin against Bcl-2 protein when compared to other metabolites and the standard drug Obatoclax (-8.4 kcal/mol). The molecular dynamics simulations revealed that the Friedelin-Bcl-2 protein complex was found to be stable throughout the simulation period of 100 ns. Overall, the predicted Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) properties of Friedelin are relatively better than Obatoclax, with the most noticeable differences in many parameters where Friedelin has no AMES toxicity, hepatotoxicity, and skin sensitization. The ADMET profiling of selected compounds supported their in silico drug-likeness properties. Based on the computational analyses, the present study concluded that Friedelin of W. trilobata was found to be the potential inhibitor of the Bcl-2 protein, which merits attention for further in vitro and in vivo studies before clinical trials.

Resolvin D5 (RvD5) Reduces Renal Damage Caused by LPS Endotoxemia in Female Mice

In self-revolving gram-negative Escherichia coli infection, Resolvin D5 (RvD5) was found to enhance bacteria phagocytosis and reduce the production of inflammatory mediators, contributing to the resolution of infection. LPS (lipopolysaccharide) is a gram-negative bacterial structure product which activates the immune system and, at high doses, leads to endotoxemia. To our knowledge, the effect of RvD5 against LPS endotoxemia has not been investigated to date. Female Swiss mice received an i.p. treatment with RvD5 (0.1, 1 or 10 ng/animal). After 1 h, they were stimulated with LPS (10 mg/kg, i.v.), and samples were collected after additional 6 h. The resulting data demonstrated that RvD5 protected the kidneys (urea and creatinine serum levels) from tissue injury. These effects were related to an improvement in histopathological parameters and a reduction of enzymatic markers of leukocyte infiltration, pro-inflammatory cytokine (IL-1β, TNF-α, and IL-6) production, and oxidative stress. Antioxidant markers were also increased by RvD5, but IL-10 (an anti-inflammatory cytokine) levels were unaltered. We also observed that RvD5 reduced the infiltration of CD45⁺ hematopoietic cells into the kidneys, reduced the activation of NFκB and promoted the Nrf2 pathway by reducing Keap-1 levels. Our data indicate that RvD5 may be a therapeutic possibility to reduce kidney lesions in LPS endotoxemia.

Sphagneticola trilobata (L.) Pruski-derived kaurenoic acid prevents ovalbumin-induced asthma in mice: Effect on Th2 cytokines, STAT6/GATA-3 signaling, NFκB/Nrf2 redox sensitive pathways, and regulatory T cell phenotype markers

ETHNOPHARMACOLOGICAL RELEVANCE

Sphagneticola trilobata (L.) Pruski is used in traditional medicine in Brazil for inflammatory diseases treatment including asthma. The diterpene kaurenoic acid (KA) is one of its active compounds, but whether KA activity could explain the traditional use of S. trilobata in asthma is unknown.

AIM

Investigate KA effect and mechanisms in asthma.

METHODS

Experimental asthma was induced by ovalbumin immunization and challenge in male Swiss mice. KA (0.1-10 mg/kg, gavage) was administered 1 h before the ovalbumin challenge. Total leukocytes, eosinophil, and mast cell were counted in bronchoalveolar lavage fluid (BALF), and lung histopathology was performed. Lung mRNA expression of Th2 and regulatory T cells markers, and BALF type 2 cytokine production were quantitated. NFκB activation and oxidative stress-related components in pulmonary tissue were measured.

RESULTS

KA inhibited the migration of total leukocytes and eosinophils to BALF, reduced lung histopathology (inflammatory cells and mast cells), mRNA expression of IL-33/ST2, STAT6/GATA-3 and NFκB activation in the lung, and reduced IL-33, IL-4, IL-5 production in the BALF. KA also reduced the mRNA expression of iNOS and gp91^phox, and superoxide anion production accompanied by the induction of Nrf2, HO-1 and NQO1 mRNA expression, thus, exerting an antioxidant effect. Finally, KA induced nTreg-like and Tr1-like, but not Th3-like markers of suppressive T cell phenotypes in the lung tissue.

CONCLUSION

KA prevents antigen-induced asthma by down-regulating Th2 and NFκB/cytokine-related pathways, and up-regulating Nrf2 and regulatory T cells' markers. Thus, explaining the ethnopharmacological use of S. trilobata for the treatment of lung inflammatory diseases.

Transcriptomics Changes in the Peritoneum of Mice with Lipopolysaccharide-Induced Peritonitis

Peritonitis caused by LPS is a severe clinical challenge, which causes organ damage and death. However, the mechanism of LPS-induced peritonitis has not been fully revealed yet. Here, we investigated the transcriptome profile of the peritoneal tissue of LPS-induced peritonitis in mice. A model of LPS-induced peritonitis in mice was established (LPS 10 mg/kg, i.p.), and the influence of TAK 242 (TLR4 inhibitor) on the level of inflammatory cytokines in mouse peritoneal lavage fluid was investigated by using an ELISA test. Next, the peritoneal tissues of the three groups of mice (Control, LPS, and LPS+TAK 242) (n = 6) were isolated and subjected to RNA-seq, followed by a series of bioinformatics analyses, including differentially expressed genes (DEGs), enrichment pathway, protein-protein interaction, and transcription factor pathway. Then, qPCR verified-hub genes that may interact with TAK 242 were obtained. Subsequently, the three-dimensional structure of hub proteins was obtained by using homology modeling and molecular dynamics optimization (300 ns). Finally, the virtual docking between TAK 242 and hub proteins was analyzed. Our results showed that TAK 242 significantly inhibited the production of inflammatory cytokines in the peritoneal lavage fluid of mice with peritonitis, including IL-6, IFN-γ, IL-1β, NO, and TNF-α. Compared with the Control group, LPS treatment induced 4201 DEGs (2442 down-regulated DEGs and 1759 up-regulated DEGs). Compared with the LPS group, 30 DEGs were affected by TAK 242 (8 down-regulated DEGs and 22 up-regulated DEGs). A total of 10 TAK 242-triggered hub genes were obtained, and the possible docking modes between TAK 242 and hub proteins were acquired. Overall, our data demonstrated that a large number of DEGs were affected in LPS-triggered peritonitis mice. Moreover, the TLR4 inhibitor TAK 242 is capable of suppressing the inflammatory response of LPS-induced peritonitis. Our work provides clues for understanding the pathogenesis of LPS-induced peritonitis in mice.

Impact of the antioxidant quercetin on morphological integrity and follicular development in the in vitro culture of Bos indicus female ovarian fragments

We evaluated the effect of quercetin on the in vitro culture of bovine ovarian fragments in relation to morphology, development, and oxidative stress. Ovaries (n = 12) from Nelore heifers (n = 6) were used. Each pair of ovaries was divided into nine fragments, and one fragment from each animal was fixed in Bouin solution for 24 h (histology control) or frozen (- 80°C; control for oxidative stress). Other ovarian fragments (n = 8) were distributed into concentrations of 0, 10, 25, and 50 μg/mL of quercetin added to the culture medium for 5 or 10 d. Data were analyzed by chi-square test or ANOVA followed by Tukey's test (P < 0.05). Treatment with 25 μg/mL quercetin resulted in the highest proportion of total intact follicles for 5 (67.3%) and 10 d (57.1%); the concentration of 25 μg/mL also presented the best proportion of developing follicles for 5 d (68.7%) and 10 d (62.8%). Treatment with 25 μg/mL quercetin resulted in significant ferric reduction for 10 d of culture, but not for 5 d. No difference (P > 0.1) was observed in the production of reactive oxygen species or in the oxidative degradation of lipids between treatments and non-cultivated controls. Treatment with 25 μg/mL quercetin preserved the morphological integrity of the developing follicles for 5 and 10 d of culture, in addition to promoting the best antioxidant potential after 10 d of culture in bovine ovarian fragments.

Anticancer, Antioxidant, and Antibacterial Activities of the Methanolic Extract from Sphagneticola trilobata (L.) J. F Pruski Leaves

This study aims to investigate the potential of bioactive secondary metabolites contained in Sphagneticola trilobata (L.) J.F Pruski leaves as novel plant-derived anticancer agent. Qualitative bioactive compound contents in the methanolic extract of S. trilobata leaves were screened using phytochemical method. Antioxidant evaluation was carried out using 2,2-diphenyl-1-picrylhydrazyl assay; antibacterial – using well diffusion method on Escherichia coli and Salmonella typhi; and cytotoxicity – using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay on MCF-7 cell line and Vero Cell. It was found that the methanolic extract exhibited antioxidant activity with an IC₅₀ value of 124.34 μg/mL. The inhibition zone values against E. coli and S. thypi (at extract concentration of 100 mg/mL) were 34.33 and 36 mm, respectively. In vitro MTT assay showed that our extract successfully reached 96% mortality with LC₅₀ = 189.287 μg/mL, where the selective index of 2.5 suggest its selectivity against MCF-7 breast cancer cell line. In conclusion, the data of biological activities suggest the potential development of methanolic extract from S. trilobata leaves as a phytomedicine for breast cancer treatment.