Optimization and validation of extraction and quantification methods of antimalarial triterpenic esters in Keetia leucantha plant and plasma

The aim of this study is to develop validated methods for the extraction and quantification of antimalarial triterpene esters from Keetia leucantha and from plasma samples. These compounds, showing in vitro and in vivo antiplasmodial activities, were optimally extracted from Keetia leucantha twigs using ultrasounds with dichloromethane and from plasma using protein precipitation with acetonitrile. We then developed and validated HPLC-UV quantification methods, which proved to be selective, accurate, linear, true and precise, both in plant and plasma samples for the eight triterpenic esters in mixture. Based on the total error concept as decision criteria, the validated dosage ranges of the triterpene esters mixture were set between 14.68 and 73.37 μg/mL in plants and 15.90 and 106.01 μg/mL in plasma injected solutions, corresponding to 7.95 and 53.01 μg/mL in plasma. These reliable methods were used to determine effectively triterpene esters content in collected samples, that seems highly variable in plant extracts, and will be helpful to further investigate pharmacokinetics parameters of these interesting bioactive compounds.

Pulmonary anti-inflammatory effects and spasmolytic properties of Costa Rican noni juice (Morinda citrifolia L.)

ETHNOPHARMACOLOGICAL RELEVANCE

Morinda citrifolia L. (Noni) is a medicinal plant used in Polynesia for many properties such as anti-inflammatory, anti-diabetic and antineoplastic effects. Recent studies showed that noni juice have anti-oxidant and acute anti-inflammatory activities likely due to polyphenols, iridoids and vitamin C content. The present study was undertaken to evaluate chronic anti-inflammatory and spasmolytic effects of noni juice.

MATERIALS AND METHODS

Therefore, we evaluated the effect of oral or intraperitoneal administrations of noni juice in vivo on the lung inflammation in ovalbumin (OVA) sensitized Brown Norway rat (with prednisolone 10mg/kg intraperitoneously as reference compound) and the ex vivo effect of noni juice on BaCl₂ (calcium signal) or methacholine (cholinergic signal) induced spasms in jejunum segments.

RESULTS

We found that noni juice (intraperitoneously 2.17mL/kg and orally 4.55mL/kg) reduced the inflammation in OVA-sensitized Brown Norway rat with regard to the decreased number of inflammatory cells in lung (macrophages minus 20-26%, lymphocytes minus 58-34%, eosinophils minus 53-30%, neutrophils minus 70-28% respectively). Noni juice demonstrated a dose-dependent NO scavenging effect up to 8.1nmol of nitrites for 50µL of noni juice. In addition noni juice inhibited (up to 90%) calcium and cholinergic induced spasms on the jejunum segments model with a rightward shift of the concentration response curve.

CONCLUSION

We describe for the first time that noni juice demonstrate (1) a chronic anti-inflammatory activity on sensitized lungs along with (2) a spasmolytic effect integrating a calcium channel blocker activity component.

A new ER-specific photosensitizer unravels (1)O2-driven protein oxidation and inhibition of deubiquitinases as a generic mechanism for cancer PDT

Photosensitizers (PS) are ideally devoid of any activity in the absence of photoactivation, and rely on molecular oxygen for the formation of singlet oxygen ((1)O2) to produce cellular damage. Off-targets and tumor hypoxia therefore represent obstacles for the use of PS for cancer photodynamic therapy. Herein, we describe the characterization of OR141, a benzophenazine compound identified through a phenotypic screening for its capacity to be strictly activated by light and to kill a large variety of tumor cells under both normoxia and hypoxia. This new class of PS unraveled an unsuspected common mechanism of action for PS that involves the combined inhibition of the mammalian target of rapamycin (mTOR) signaling pathway and proteasomal deubiquitinases (DUBs) USP14 and UCH37. Oxidation of mTOR and other endoplasmic reticulum (ER)-associated proteins drives the early formation of high molecular weight (MW) complexes of multimeric proteins, the concomitant blockade of DUBs preventing their degradation and precipitating cell death. Furthermore, we validated the antitumor effects of OR141 in vivo and documented its highly selective accumulation in the ER, further increasing the ER stress resulting from (1)O2 generation upon light activation.

Small Molecule Inhibition of ERK Dimerization Prevents Tumorigenesis by RAS-ERK Pathway Oncogenes

Nearly 50% of human malignancies exhibit unregulated RAS-ERK signaling; inhibiting it is a valid strategy for antineoplastic intervention. Upon activation, ERK dimerize, which is essential for ERK extranuclear, but not for nuclear, signaling. Here, we describe a small molecule inhibitor for ERK dimerization that, without affecting ERK phosphorylation, forestalls tumorigenesis driven by RAS-ERK pathway oncogenes. This compound is unaffected by resistance mechanisms that hamper classical RAS-ERK pathway inhibitors. Thus, ERK dimerization inhibitors provide the proof of principle for two understudied concepts in cancer therapy: (1) the blockade of sub-localization-specific sub-signals, rather than total signals, as a means of impeding oncogenic RAS-ERK signaling and (2) targeting regulatory protein-protein interactions, rather than catalytic activities, as an approach for producing effective antitumor agents.

Chemical composition and anti-inflammatory properties of the unsaponifiable fraction from awara (Astrocaryum vulgare M.) pulp oil in activated J774 macrophages and in a mice model of endotoxic shock

Awara (Astrocaryum vulgare M.) pulp oil has been shown to possess anti-inflammatory properties in vivo, and contains an unsaponifiable matter rich in bioactive compounds. This study focused on the ethanolic unsaponifiable fraction (EUF) of awara pulp oil. Its chemical composition has been characterized: carotenoid, phytosterol, and tocopherol contents represent 125.7, 152.6, and 6.8 μg/mg of EUF, respectively. We further evaluated this fraction for anti-inflammatory properties in J774 macrophages activated by lipopolysaccharide (LPS) plus interferon (IFN) γ to understand the biological effects of awara pulp oil. EUF strongly decreased nitric oxide (NO), prostaglandin E(2), tumour necrosis factor (TNF) α, and interleukin (IL) -6 and -10 production in activated J774 cells. Moreover, it inhibited expression of inducible NO synthase and cyclooxygenases-2 in vitro. The anti-inflammatory properties of EUF were also confirmed in vivo by modulation of TNFα, IL-6 and IL-10 serum concentration in an endotoxic shock model. Pre-treatment with awara oil fraction offers promise as a protective means to lower the production of excessive amounts of pro-inflammatory molecules.

Characterization, anti-oxidative and anti-inflammatory effects of Costa Rican noni juice (Morinda citrifolia L.)

AIM OF THE STUDY

Noni fruit (Morinda citrifolia L.) juice has been used for more than 2000 years in Polynesia as a traditional folk medicine. The aim of the present study was to finely characterize noni juice from Costa Rica and to evaluate its anti-oxidative and anti-inflammatory activities.

MATERIALS AND METHODS

A microfiltrated noni juice was prepared with Costarican nonis. HPLC-DAD and Electro Spray Ionization Mass Spectrometric detection (HPLC-ESI-MS) were used to identify phenolic compounds and iridoids. The anti-oxidative activity of noni juice was measured in vitro by both Oxygen Radical Absorbance Capacity (ORAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging methods. The anti-inflammatory effects of noni juice were investigated in vitro by: measuring its effect on nitric oxide and prostaglandin E2 production by activated macrophages, evaluating its inhibitory activities on cyclooxygenase (COX)-1 and -2 and in vivo on a carrageenan-induced paw oedema model in rats.

RESULTS

Several polyphenols belonging to the coumarin, flavonoid and phenolic acid groups, and two iridoids were identified. Noni juice demonstrated a mean range free radical scavenging capacity. Furthermore, it also reduced carrageenan-induced paw oedema, directly inhibited cyclooxygenase COX-1 and COX-2 activities and inhibited the production of nitric oxide (NO) and prostaglandins E(2) (PGE(2)) in activated J774 cells, in a dose dependent manner.

CONCLUSIONS

This study showed that noni's biological effects include: (1) anti-oxidant properties probably associated with phenolic compounds, iridoids and ascorbic acid and (2) anti-inflammatory action through NO and PGE(2) pathways that might also be strengthened by anti-oxidant effects.