An Investigation on the Quantitative Structure-Activity Relationships of the Anti-Inflammatory Activity of Diterpenoid Alkaloids

Anti-Inflammatory Effects of Natural Products on Cerebral Ischemia

Cerebral ischemia with high mortality and morbidity still requires the effectiveness of medical treatments. A growing number of investigations have shown strong links between inflammation and cerebral ischemia. Natural medicine’s treatment methods of cerebral ischemic illness have amassed a wealth of treatment experience and theoretical knowledge. This review summarized recent progress on the disease inflammatory pathways as well as 26 representative natural products that have been routinely utilized to treat cerebral ischemic injury. These natural products have exerted anti-inflammatory effects in cerebral ischemia based on their inflammatory mechanisms, including their inflammatory gene expression patterns and their related different cell types, and the roles of inflammatory mediators in ischemic injury. Overall, the combination of the potential therapeutic interventions of natural products with the inflammatory mechanisms will make them be applicable for cerebral ischemic patients in the future.

Evaluation of the In Vitro Antimicrobial Activities of Delphinium roylei: An Insight from Molecular Docking and MD-Simulation Studies

ETHNOPHARMACOLOGICAL RELEVANCE

The burden of antimicrobial resistance demands a continued search for new antimicrobial drugs. The synthetic drugs which are used clinically have serious side effects. Natural products or compounds derived from natural sources show diversity in structure and play an essential role in drug discovery and development.

OBJECTIVE

Delphinium roylei is an important medicinal herb of Kashmir Himalaya, India. Traditionally this medicinal plant treats liver infections, skin problems, and chronic lower back pain. The current study evaluates the antimicrobial potential by various in -vitro and in -silico parameters.

METHODS

Three extracts and 168 bioactive compounds analysed through LC-MS data, with the vast majority of them having therapeutic applications of D. roylei, have been screened for the antimicrobial activity against bacteria (E. coli, M. luteus, K. pneumoniae, Streptococcus pneumonia, Haemophilus influenzae, Neisseria mucosa) and fungi (Candida albicans, Candida glabrata, Candida Paropsilosis) species through molecular docking using autodock Vina, MD simulation and broth microdilution method for minimum inhibitory concentration (MIC) evaluation.

RESULTS

The extracts, as well as the compounds analyzed through the LC-MS technique of Delphinium roylie showed significant antimicrobial activity.

CONCLUSION

Our study established that the leaf extracts of Delphinium roylei exhibit antimicrobial activity and thus confirm its importance in traditional medicine.

Uncovering the anti-angiogenic effect of semisynthetic triterpenoid CDDO-Im on HUVECs by an integrated network pharmacology approach

AIM

To reveal the molecular mechanism of anti-angiogenic activity of semisynthetic triterpenoid CDDO-Im.

MATERIALS AND METHODS

Using re-analysis of cDNA microarray data of CDDO-Im-treated human vascular endothelial cells (HUVECs) (GSE71622), functional annotation of revealed differentially expressed genes (DEGs) and analysis of their co-expression, the key processes induced by CDDO-Im in HUVECs were identified. Venn diagram analysis was further performed to reveal the common DEGs, i.e. genes both susceptible to CDDO-Im and involved in the regulation of angiogenesis. A list of probable protein targets of CDDO-Im was prepared based on Connectivity Map/cheminformatics analysis and chemical proteomics data, among which the proteins that were most associated with the angiogenesis-related regulome were identified. Finally, identified targets were validated by molecular docking and text mining approaches.

KEY FINDINGS

The effect of CDDO-Im in HUVECs can be divided into two main phases: the short early phase (0.5-3 h) with an acute FOXD1/CEBPA/JUNB-regulated pro-angiogenic response induced by xenobiotic stress, and the second anti-angiogenic step (6-24 h) with massive suppression of various angiogenesis-related processes, accompanied by the activation of cytoprotective mechanisms. Our analysis showed that the anti-angiogenic activity of CDDO-Im is mediated by its inhibition of the expression of PLAT, ETS1, A2M, SPAG9, RASGRP3, FBXO32, GCNT1 and HDGFRP3 and its direct interactions with EGFR, mTOR, NOS2, HSP90AA1, MDM2, SYK, IRF3, ATR and KIF14.

SIGNIFICANCE

Our findings provide valuable insights into the understanding of the molecular mechanisms of the anti-angiogenic activity of cyano enone-bearing triterpenoids and revealed a range of novel promising therapeutic targets to control pathological neovascularization.

Classification, Toxicity and Bioactivity of Natural Diterpenoid Alkaloids

Diterpenoid alkaloids are natural compounds having complex structural features with many stereo-centres originating from the amination of natural tetracyclic diterpenes and produced primarily from plants in the Aconitum, Delphinium, Consolida genera. Corals, Xenia, Okinawan/Clavularia, Alcyonacea (soft corals) and marine sponges are rich sources of diterpenoids, despite the difficulty to access them and the lack of availability. Researchers have long been concerned with the potential beneficial or harmful effects of diterpenoid alkaloids due to their structural complexity, which accounts for their use as pharmaceuticals as well as their lousy reputation as toxic substances. Compounds belonging to this unique and fascinating family of natural products exhibit a broad spectrum of biological activities. Some of these compounds are on the list of clinical drugs, while others act as incredibly potent neurotoxins. Despite numerous attempts to prepare synthetic products, this review only introduces the natural diterpenoid alkaloids, describing 'compounds' structures and classifications and their toxicity and bioactivity. The purpose of the review is to highlight some existing relationships between the presence of substituents in the structure of such molecules and their recognised bioactivity.

Research progress on the protection and detoxification of phytochemicals against aflatoxin B1-Induced liver toxicity

Aflatoxin B₁ (AFB₁) is a potent hepatotoxic toxin, which can cause hepatitis, cirrhosis, and liver immunological damage. It has been involved in the etiology of human hepatocellular carcinoma. AFB₁ can cause oxidative stress in the body's metabolism process, and then cause cytotoxicity, such as apoptosis and DNA damage. Scientific research has discovered that phytochemicals can induce the detoxification pathway of AFB₁ through its biotransformation, thereby reducing the damage of AFB₁ to the human body. In clinical treatment, certain phytochemicals have been effectively used in the treatment of liver injury due to the advantages of multiple targets, multiple pathways, low toxicity and side effects. Therefore, the article summarizes the toxic mechanism of AFB₁-induced hepatoxicity, and the related research progress of phytochemicals for preventing and treating its cytotoxicity and genotoxicity. We also look forward to the existing problems and application prospects of phytochemicals in the pharmaceutical industry, in order to provide theoretical reference for the prevention and treatment of AFB₁ poisoning in future research work.

Synthesis, in vitro and in vivo biological evaluation of novel lappaconitine derivatives as potential anti-inflammatory agents

Lappaconitine (LA), a natural compound with a novel C18-diterpenoid alkaloid skeleton, displayed extensive biological profile. Recent research on LA is focused mainly on its anti-tumor and analgesic effects, and therefore we aimed to investigate its anti-inflammatory potential. A series of novel LA derivatives with various substituents on the 20-N position was designed and synthesized. In the initial screening of LA derivatives against NO production, all the target compounds, except compound E2, exhibited excellent inhibitory ability relative to that of LA. Particularly, compound A4 exhibited the most potent inhibition with IC₅₀ of 12.91 μmol/L. The elementary structure-activity relationships (SARs) of NO inhibitory activity indicated that replacement of the benzene ring with an electron donating group could improve the anti-inflammatory efficacy. Furthermore, compound A4 shows an anti-inflammatory mechanism by inhibiting NO, PGE2, and TNF-α generation via the suppression of NF-κB and MAPK signaling pathways. Notably, compound A4 could exert a significant therapeutic effect on LPS-induced acute lung injury (ALI) in vivo. Based on the above research, we further investigated the preliminary pharmacokinetic property of A4 in rats. Therefore, compound A4 could be a promising candidate for the development of anti-inflammatory agents in the future.

Assessment of the antinociceptive and anti-inflammatory activities of the stem methanol extract of Diplotropis purpurea

Context: Since there is still a great need to search for plant species with antinociceptive and anti-inflammatory activities, Diploptropis purpurea (Rich.) Amshoff (Fabaceae) is studied for the first time. Objective: This evaluates the analgesic and anti-inflammatory activities of the stem methanol extract of Diplotropis purpurea (MEDP). Material and methods: The anti-inflammatory and analgesic effects of MEDP of D. purpurea were evaluated in vivo. The antinociceptive activity was assessed in CD1 male mice were treated by oral gavage with 500 mg/kg of MEDP 30 min before submitting to acetic acid-induced abdominal writhing, hot-plate, and formalin tests. Paws oedema induced by carrageenan, histamine or serotonin were performed in male Sprague-Dawley rats to determinate the anti-inflammatory activity. Results: Oral administration of MEDP produced significant antinociceptive effects on the inflammatory phase in the formalin test [12.0 s versus 72.5 s in carboxymethyl cellulose (CMC) control group]. MEDP produced an analgesic effect in the hot-plate model, although the effect was modest compared to tramadol (40 and 60%, respectively). The oral administration of MEDP in a dose of 500 mg/kg showed maximum inhibition (75.1%) after 0.5 h in carrageenan-induced oedema, but it did not modify histamine or serotonin-induced oedemas. Discussion and conclusion: In the peripheral nociception model, acetic acid-induced abdominal writhing, the MEDP did not show a protective effect, but its analgesic effects were evident in the inflammatory phase of the formalin test and in the hot-plate model. These results show that the anti-inflammatory effect was accompanied by a reduction in the perception of painful stimuli.

Screening and isolation of cyclooxygenase-2 inhibitors from the stem bark of Phellodendron amurense Ruprecht by ultrafiltration with liquid chromatography and tandem mass spectrometry, and complex chromatography

Nonsteroidal anti-inflammatory drugs appear to reduce the risk of developing cancer. One mechanism through which nonsteroidal anti-inflammatory drugs act to prevent carcinogenesis is inhibition of the activity of the enzyme cyclooxygenase-2. The cyclooxygenase-2 inhibitors are widely used to reduce the risk of developing cancer. Natural products are considered to be a promising source of several novel cyclooxygenase-2 inhibitors. Ultrafiltration with liquid chromatography and mass spectrometry is an efficient method that can be applied to rapidly screen and identify the ligands from the barks of Phellodendron amurense Ruprecht. A continuous online method comprised of pressurized liquid extraction, countercurrent chromatography, and semi-preparative liquid chromatography was developed for the efficient scaled-up production of eight compounds with high purities. The bioactivities of the separated compounds were assessed by an in vitro enzyme inhibition assay. The use of bioactivity screening method combined with preparation method of bioactive compounds and an in vitro enzyme inhibition assay facilitated the efficient screening and isolation of the cyclooxygenase-2 inhibitors from complex samples. This could be used as an efficient method for the large-scale production of functional ingredients.

Himatanthus drasticus Leaves: Chemical Characterization and Evaluation of Their Antimicrobial, Antibiofilm, Antiproliferative Activities

Plant-derived products have played a fundamental role in the development of new therapeutic agents. This study aimed to analyze antimicrobial, antibiofilm, cytotoxicity and antiproliferative potentials of the extract and fractions from leaves of Himatanthusdrasticus, a plant from the Apocynaceae family. After harvesting, H. drasticus leaves were macerated and a hydroalcoholic extract (HDHE) and fractions were prepared. Antimicrobial tests, such as agar-diffusion, Minimum Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) were carried out against several bacterial species. Staphylococcus aureus, Pseudomonas aeruginosa, Listeria monocytogenes and Klebsiella pneumoniae were inhibited by at least one extract or fraction in the agar-diffusion assay (inhibition halos from 12 mm to 30 mm). However, the lowest MIC value was found for HDHE against K. pneumoniae. In addition, HDHE and its fractions were able to inhibit biofilm formation at sub-inhibitory concentrations (780 µg/mL and 1.56 µg/mL). As the best activities were found for HDHE, we selected it for further assays. HDHE was able to increase ciprofloxacin (CIP) activity against K. pneumoniae, displaying synergistic (initial concentration CIP + HDHE: 2 µg/mL + 600 µg/mL and 2.5 µg/mL + 500 µg/mL) and additive effects (CIP + HDHE: 3 µg/mL + 400 µg/mL). This action seems to be associated with the alteration in bacterial membrane permeability induced by HDHE (as seen by propidium iodide labeling). This extract was non-toxic for red blood cell or human peripheral blood mononuclear cells (PBMCs). Additionally, it inhibited the lipopolysaccharide-induced proliferation of PBMCs. The following compounds were detected in HDHE using HPLC-ESI-MS analysis: plumieride, plumericin or isoplumericin, rutin, quercetin and derivatives, and chlorogenic acid. Based on these results we suggest that compounds from H. drasticus have antimicrobial and antibiofilm activities against K. pneumoniae and display low cytotoxicity and anti-proliferative action in PBMC stimulated with lipopolysaccharide.