Oleanolic Acid Complexation with Cyclodextrins Improves Its Cell Bio-Availability and Biological Activities for Cell Migration

Wound healing is a complex process to restore skin. Plant-derived bioactive compounds might be a source of substances for the treatment of wounds stalled in a non-resolving stage of wound healing. Oleanolic acid (OA), a pentacyclic triterpene, has shown favorable wound healing properties both in vitro and in vivo. Unfortunately, OA cannot be solubilized in aqueous media, and it needs to be helped by the use of dimethyl sulfoxide (DMSO). In this paper, we have shown that cyclodextrins (CDs) are a good alternative to DMSO as agents to deliver OA to cells, providing better features than DMSO. Cyclodextrins are natural macromolecules that show a unique tridimensional structure that can encapsulate a wide variety of hydrophobic compounds. We have studied the cyclodextrin-encapsulated form of OA with OA/DMSO, comparing their stability, biological properties for cell migration, and cell viability. In addition, detailed parameters related to cell migration and cytoskeletal reorganization have been measured and compared. Our results show that OA-encapsulateds compound exhibit several advantages when compared to non-encapsulated OA in terms of chemical stability, migration enhancement, and preservation of cell viability.

The Inhibitory Effects of Pentacyclic Triterpenes from Loquat Leaf against Th17 Differentiation

BACKGROUND

Loquat leaf is an herb that is commonly used in traditional Chinese medicine (TCM) for its anti-inflammatory properties. Numerous studies have demonstrated that Th17 cells play a fundamental role in mediating SLE pathological deterioration. In our study, we investigated the inhibitory effect of pentacyclic triterpenes from loquat leaf on T helper 17 (Th17) cells and the therapeutic efficacy of OA in Lupus nephritis (LN) development.

METHODS

We isolated three pentacyclic triterpene compounds rom loquat leaf by bioassay-directed fractionation and separation method. There were methyl corosolate (MC), uvaol (UL), and oleanolic acid (OA) Firstly, we elucidated Retinoic acid receptor-related orphan receptor gamma t (RORγt) inhibitory activity of these three compounds in the cell-based assay and Th17 differentiation in vitro assay. Then, we used OA-treated pristine-induced LN mice to evaluate the therapeutic effects of OA in LN development. Anti-dsDNA level in serum was detected by enzyme-linked immunosorbent assay (ELISA), interleukin 17A (IL-17A) and interferon-γ (IFN-γ) expression in spleen cells by Flow cytometry (FCM), histomorphologic examination of kidneys were performed by periodic acid schiff (PAS) staining and immunofluorescence analysis.

RESULTS

Pentacyclic triterpene compounds (MC, UL, OA) displayed inhibition of RORγt activity in cell-based assay and Th17 differentiation in vitro. Furthermore, our results also showed that OA could significantly decrease serum anti-dsDNA antibody levels, IL-17A and IFN-γ expression and alleviate renal pathological damage in OA-treated group mice than in the model group mice.

CONCLUSION

These results demonstrated that OA can improve the clinical manifestation of LN, indicating potential application in SLE therapy.

Erratum: A novel AMPK activator from Chinese herb medicine and ischemia phosphorylate the cardiac transcription factor FOXO3

[This corrects the article on p. 116 in vol. 1, PMID: 20445824.].

Pharmacokinetics in Vitro and in Vivo of Two Novel Prodrugs of Oleanolic Acid in Rats and Its Hepatoprotective Effects against Liver Injury Induced by CCl4

Oleanolic acid (OA) is a well-known pentacyclic triterpenoid compound, which has been used as a dietary supplement and is supplied as an over-the-counter drug for the treatment of human liver diseases. These are reasons for the low bioavailability of OA which have restricted its wider application. In this study, two OA prodrugs (1,3-cyclic propanyl phosphate esters of OA) were designed and synthesized. The hepatoprotective effects of these prodrugs were evaluated against carbon tetrachloride (CCl4) induced liver injury in mice; the levels of alanine aminotransferase (ALT), lactic dehydrogenase (LDH), and aspartate aminotransferase (AST) were significantly increased, and the level of the hepatic malondialdehyde (MDA) was increased. The metabolism, in vitro, of the prodrugs was studied by incubation in rat liver microsome; the plasma pharmacokinetics and the biodistribution in vivo after intravenous (iv) injection to six rats were investigated, respectively. The prodrugs diminished gradually with time; most of the parent drugs were released within 30 min in vitro, and the presumed mechanism of the in vitro metabolism was confirmed. The plasma-concentration data in vivo was analyzed by a compartmental method: both the prodrugs and the corresponding released parent drugs existed at up to 48 h in rats. The t1/2 improved after intravenous administration in rats compared with direct injection of the parent drugs. All analyte concentrations were highest in the liver, and most of the prodrugs were excreted in feces (>47.11%). Therefore, 1,3-cyclic propanyl phosphate esters of OA can serve as a promising lead candidate for drugs.

Erratum: A novel AMPK activator from Chinese herb medicine and ischemia phosphorylate the cardiac transcription factor FOXO3

Oleanolic Acid (OA) is a nature product extracted from Chinese Herb Medicine which is traditionally used as treatment of diabetes and ischemic heart diseases. Mounting evidence showed that AMP-activated protein kinase (AMPK) has cardioprotective effect against ischemic injury and the forkhead transcription factor 3 (FOXO3) was recently identified as a downstream target of AMPK. We hypothesize that OA may protect against ischemic dysfunction of cardiomyocytes via activation of AMPK signaling pathway. Male C57BL/6 mice which were subjected to in vivo regional cardiac ischemia stimulated AMPK Thr(172) phosphorylation, as well as phosphorylation of downstream FOXO3 (Ser(413)) and acetyl CoA carboxylase (ACC). The natural product, OA, significantly stimulated cardiac AMPK activation in cardiomyocyes in time- and dose-dependent manners. The mechanism of AMPK activation by OA may be due to the loss mitochondrial membrane potential (ΔΨm) as shown by JC-1 fluorescence assay. Intriguingly, OA as an AMPK activator also triggered FOXO3 (Ser(413)) phosphorylation in cardiomyocytes. Furthermore, OA treatment can protect cardiomyocytes from contractile dysfunction induced by hypoxia. Taken together, the results indicated that both ischemia and OA stimulated cardiac AMPK phosphorylation, as well downstream FOXO3 phosphorylation. The cardioprotective effect of OA maybe associated with activation of AMPK signaling pathways.[This corrects the article on p. 116 in vol. 1, PMID: 20445824.].

Quantification of Oleanolic acid in the flower of Gentiana olivieri Griseb. by HPLC

High Performance Liquid Chromatography (HPLC) method is a potent analytical technique for determining phytoconstituents even in minute quantities particularly that are generally present in traces concentrations in medicinal plants. The concentration of oleanolic acid (OA) in the Gentiana olivieri Griseb.(GOG) flowers is quantitatively determined by a simple, precise and accurate HPLC method. HPLC assay was performed on reversed-phase C18 column and compound was detected at 210 nm with a flow rate of 1.0 ml/min. The mobile phase consisted of methanol (A) and 0.03 mol/L phosphate buffer, pH 2.9 (B) with a ratio of 85:15 (A: B v/v).The method showed good precision and accuracy with overall intra-day and inter-day variation of 0.36-1.33% and 0.43-1.15%, respectively, and overall recoveries of 99.32%. Application of these methods to determine the OA in Gentiana olivieri Griseb showed that the concentration of OA was found more in the flower as compared to the whole aerial part (average amount in flower 1.82 mg/g DW and 0.75 mg/g DW in whole aerial plant). A simple and accurate HPLC method has been developed for quantitative determination of OA in GOG flowers.