Inhibitory effect of oleanolic acid on 12-O-tetradecanoylphorbol-13-acetate-induced gene expression in mouse skin

Synthesis and biological evaluations of oleanolic acid indole derivatives as hyaluronidase inhibitors with enhanced skin permeability

Oleanolic acid (OA) is a natural cosmeceutical compound with various skin beneficial activities including inhibitory effect on hyaluronidase but the anti-hyaluronidase activity and mechanisms of action of its synthetic analogues remain unclear. Herein, a series of OA derivatives were synthesised and evaluated for their inhibitory effects on hyaluronidase. Compared to OA, an induction of fluorinated (6c) and chlorinated (6g) indole moieties led to enhanced anti-hyaluronidase activity (IC₅₀ = 80.3 vs. 9.97 and 9.57 µg/mL, respectively). Furthermore, spectroscopic and computational studies revealed that 6c and 6g can bind to hyaluronidase protein and alter its secondary structure leading to reduced enzyme activity. In addition, OA indole derivatives showed feasible skin permeability in a slightly acidic environment (pH = 6.5) and 6c exerted skin protective effect by reducing cellular reactive oxygen species in human skin keratinocytes. Findings from the current study support that OA indole derivatives are potential cosmeceuticals with anti-hyaluronidase activity.

Viral UL8 Is Involved in the Antiviral Activity of Oleanolic Acid Against HSV-1 Infection

Herpes simplex virus type 1 (HSV-1) is highly prevalent in humans and can cause severe diseases, especially in immunocompromised adults and newborns, such as keratitis and herpes simplex encephalitis. At present, the clinical therapeutic drug against HSV-1 infection is acyclovir (ACV), and its extensive usage has led to the emergence of ACV-resistant strains. Therefore, it is urgent to explore novel therapeutic targets and anti-HSV-1 drugs. This study demonstrated that Oleanolic acid, a pentacyclic triterpenoid widely existing in natural product, had strong antiviral activity against both ACV-sensitive and -resistant HSV-1 strains in different cells. Mechanism studies showed that Oleanolic acid exerted its anti-HSV-1 activity in the immediate early stage of infection, which involved the dysregulation of viral UL8, a component of viral helicase-primase complex critical for viral replication. In addition, Oleanolic acid significantly ameliorated the skin lesions in an HSV-1 infection mediated zosteriform model. Together, our study suggested that Oleanolic acid could be a potential candidate for clinical therapy of HSV-1 infection-related diseases.

Oleanolic acid induces p53-dependent apoptosis via the ERK/JNK/AKT pathway in cancer cell lines in prostatic cancer xenografts in mice

We evaluated oleanolic acid (OA)-induced anti-cancer activity, apoptotic mechanism, cell cycle status, and MAPK kinase signaling in DU145 (prostate cancer), MCF-7 (breast cancer), U87 (human glioblastoma), normal murine liver cell (BNL CL.2) and human foreskin fibroblast cell lines (Hs 68). The IC50 values for OA-induced cytotoxicity were 112.57 in DU145, 132.29 in MCF-7, and 163.60 in U87 cells, respectively. OA did not exhibit toxicity in BNL CL. 2 and Hs 68 cell lines in our experiments. OA, at 100 µg/mL, increased the number of apoptotic cells to 27.0% in DU145, 27.0% in MCF-7, and 15.7% in U87, when compared to control cells. This enhanced apoptosis was due to increases in p53, cytochrome c, Bax, PARP-1 and caspase-3 expression in DU145, MCF-7 and U87 cell lines. OA-treated DU145 cells were arrested in G2 because of the activation of p-AKT, p-JNK, p21 and p27, and the decrease in p-ERK, cyclin B1 and CDK2 expression; OA-treated MCF-7 cells were arrested in G1 owing to the activation of p-JNK, p-ERK, p21, and p27, and the decrease in p-AKT, cyclin D1, CDK4, cyclin E, and CDK2; and OA-treated U87 cells also exhibited G1 phase arrest caused by the increase in p-ERK, p-JNK, p-AKT, p21, and p27, and the decrease in cyclin D1, CDK4, cyclin E and CDK2. Thus, OA arrested the cell cycle at different phases and induced apoptosis in cancer cells. These results suggested that OA possibly altered the expression of the cell cycle regulatory proteins differently in varying types of cancer.

Ng VA, Shen CC, Ragasa CY. Cytotoxic Compounds from Wrightia pubescens (R.Br.)

BACKGROUND

Mixtures of ursolic acid (1) and oleanolic acid (2) (1:1 and 1:2), oleanolic acid (2), squalene (3), chlorophyll a (4), wrightiadione (5), and α-amyrin acetate (6) were isolated from the dichloromethane (CH2 Cl2) extracts of the leaves and twigs of Wrightia pubescens (R.Br.).

OBJECTIVES

To test for the cytotoxicity potentials of 1-6.

MATERIALS AND METHODS

The antiproliferative activities of 1-6 against three human cancer cell lines, breast (MCF-7) and colon (HT-29 and HCT-116), and a normal cell line, human dermal fibroblast neonatal (HDFn), were evaluated using the PrestoBlue® cell viability assay.

RESULTS

Compounds 4, 1 and 2 (1:2), 2, 1 and 2 (1:1), and 5 exhibited the most cytotoxic effects against HT-29 with half maximal inhibitory concentration (IC50) values of 0.68, 0.74, 0.89, 1.70, and 4.07 μg/mL, respectively. Comparing 2 with its 1:1 mixture with 1 (IC50 = 1.70 and 7.18 μg/mL for HT-29 and HCT-116, respectively) and 1:2 mixture with 1 (0.74 and 3.46 μg/mL for HT-29 and HCT-116, respectively), 2 also showed strong cytotoxic potential against HT-29 and HCT-116 (0.89 and 2.33 μg/mL, respectively). Unlike the mixtures which exhibited low effects on MCF-7 (IC50 = 20.75 and 30.06 μg/mL for 1:1 and 1:2, respectively), 2 showed moderate activity against MCF-7 (10.99 μg/mL). Compound 6 showed the highest cytotoxicity against HCT-116 (IC50 = 4.07 μg/mL).

CONCLUSION

Mixtures of 1 and 2 (1:1 and 1:2), 2, 3, 4, 5, and 6 from the CH2 Cl2 extracts of the leaves and twigs of W. pubescens (R.Br.) exhibited varying cytotoxic activities. All the compounds except 6 exhibited the strongest cytotoxic effects against HT-29. On the other hand, 6 was most cytotoxic against HCT-116. Overall, the toxicities of 1-6 were highest against HT-29, followed by HCT-116 and MCF-7. All the compounds showed varying activities against HDFn (IC50 < 30 μg/mL).

SUMMARY

Mixtures of ursolic acid (1) and oleanolic acid (2) (1:1 and 1:2), oleanolic acid (2), squalene (3), chlorophyll a (4), wrightiadione (5), and α-amyrin acetate (6), isolated from the dichloromethane extracts of the leaves and twigs of Wrightia pubescens (R.Br.), showed varying cytotoxic activities against three human cancer cell lines, breast (MCF-7) and colon (HT-29 and HCT-116), and a normal cell line, human dermal fibroblast-neonatal (HDFn), as evaluated using the PrestoBlue® cell viability assay.Abbreviation Used: IC50: Half maximal inhibitory concentration.

Oleanolic Acid Alters Multiple Cell Signaling Pathways: Implication in Cancer Prevention and Therapy

Nowadays, much attention has been paid to diet and dietary supplements as a cost-effective therapeutic strategy for prevention and treatment of a myriad of chronic and degenerative diseases. Rapidly accumulating scientific evidence achieved through high-throughput technologies has greatly expanded the understanding about the multifaceted nature of cancer. Increasingly, it is being realized that deregulation of spatio-temporally controlled intracellular signaling cascades plays a contributory role in the onset and progression of cancer. Therefore, targeting regulators of oncogenic signaling cascades is essential to prevent and treat cancer. A plethora of preclinical and epidemiological evidences showed promising role of phytochemicals against several types of cancer. Oleanolic acid, a common pentacyclic triterpenoid, is mainly found in olive oil, as well as several plant species. It is a potent inhibitor of cellular inflammatory process and a well-known inducer of phase 2 xenobiotic biotransformation enzymes. Main molecular mechanisms underlying anticancer effects of oleanolic acid are mediated by caspases, 5' adenosine monophosphate-activated protein kinase, extracellular signal-regulated kinase 1/2, matrix metalloproteinases, pro-apoptotic Bax and bid, phosphatidylinositide 3-kinase/Akt1/mechanistic target of rapamycin, reactive oxygen species/apoptosis signal-regulating kinase 1/p38 mitogen-activated protein kinase, nuclear factor-κB, cluster of differentiation 1, CKD4, s6k, signal transducer and activator of transcription 3, as well as aforementioned signaling pathways . In this work, we critically review the scientific literature on the molecular targets of oleanolic acid implicated in the prevention and treatment of several types of cancer. We also discuss chemical aspects, natural sources, bioavailability, and safety of this bioactive phytochemical.

Evaluation of pentacyclic triterpenes found in Perilla frutescens for inhibition of skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate

A series of pentacyclic tritperpenes found in Perilla frutescens (P. frutescens), including ursolic acid (UA), oleanolic acid (OA), corosolic acid (CA), 3-epi-corosolic acid (3-epiCA), maslinic acid (MA), and 3-epi-maslinic acid (3-epiMA) were evaluated for their effects on epidermal cell signaling, proliferation, and skin inflammation in relation to their ability to inhibit skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA) and compared to UA as the prototype compound. All compounds were given topically 30 min prior to each TPA application and significantly inhibited skin tumor promotion. 3-epiCA and MA were significantly more effective than UA at inhibiting tumor development. All of these compounds significantly inhibited epidermal proliferation induced by TPA, however, CA, 3-epiCA and MA were more effective than UA. All compounds also reduced skin inflammation (assessed by infiltration of mast cells and T-cells) and inflammatory gene expression induced by TPA, however, 3-epiCA and MA were again more effective than UA. The greater ability of 3-epiCA and MA to inhibit skin tumor promotion was associated with greater reduction of Cox-2 and Twist1 proteins and inhibition of activation (i.e., phosphorylation) of IGF-1R, STAT3 and Src. Further study of these compounds, especially 3-epiCA and MA, for chemopreventive activity in other cancer model systems is warranted.

Oleanolic acid and its synthetic derivatives for the prevention and therapy of cancer: preclinical and clinical evidence

Oleanolic acid (OA, 3β-hydroxyolean-12-en-28-oic acid) is a ubiquitous pentacyclic multifunctional triterpenoid, widely found in several dietary and medicinal plants. Natural and synthetic OA derivatives can modulate multiple signaling pathways including nuclear factor-κB, AKT, signal transducer and activator of transcription 3, mammalian target of rapamycin, caspases, intercellular adhesion molecule 1, vascular endothelial growth factor, and poly (ADP-ribose) polymerase in a variety of tumor cells. Importantly, synthetic derivative of OA, 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO), and its C-28 methyl ester (CDDO-Me) and C28 imidazole (CDDO-Im) have demonstrated potent antiangiogenic and antitumor activities in rodent cancer models. These agents are presently under evaluation in phase I studies in cancer patients. This review summarizes the diverse molecular targets of OA and its derivatives and also provides clear evidence on their promising potential in preclinical and clinical situations.

Self-microemulsifying drug delivery system for improved oral bioavailability of oleanolic acid: design and evaluation

Oleanolic acid is a poorly water-soluble drug with low oral bioavailability. A self-microemulsifying drug delivery system (SMEDDS) has been developed to enhance the solubility and oral bioavailability of oleanolic acid. The formulation design was optimized by solubility assay, compatibility tests, and pseudoternary phase diagrams. The morphology, droplet size distribution, zeta potential, viscosity, electrical conductivity, and refractive index of a SMEDDS loaded with oleanolic acid were studied in detail. Compared with oleanolic acid solution, the in vitro release of oleanolic acid from SMEDDS showed that the drug could be released in a sustained manner. A highly selective and sensitive high-performance liquid chromatographymass spectrometry method was developed for determination of oleanolic acid in rat plasma. This method was used for a pharmacokinetic study of an oleanolic acid-loaded SMEDDS compared with the conventional tablet in rats. Promisingly, a 5.07-fold increase in oral bioavailability of oleanolic acid was achieved for the SMEDDS compared with the marketed product in tablet form. Our studies illustrate the potential use of a SMEDDS for delivery of oleanolic acid via the oral route.