Long-chain Alkanes andent-Labdane-type Diterpenes fromGymnosperma glutinosumwith Cytotoxic Activity Against the Murine Lymphoma L5178Y-R

Pharmacological evaluation of 2-angeloyl ent-dihydrotucumanoic acid

CONTEXT

Gymnosperma glutinosum (Spreng.) Less. (Asteraceae) is a bush used for the empirical treatment of pain, fever, and cancer. An ent-neo-clerodane diterpene (2-angeloyl ent-dihydrotumanoic acid; ADTA) was isolated from G. glutinosum.

OBJECTIVE

This study evaluates the cytotoxic, anti-inflammatory, and antinociceptive effects of ADTA.

MATERIALS AND METHODS

The cytotoxic effects of ADTA (1-350 μM) were evaluated using the MTT assay with human tumorigenic (SW-620, MDA-MB231, SKLU1, SiHa, and PC-3), and non-tumorigenic (HaCaT) cells for 48 h. The in vitro anti-inflammatory effects of ADTA (0.23-460 μM) were assessed using murine peritoneal macrophages stimulated with LPS and estimating the levels of pro-inflammatory mediators for 48 h. The antinociceptive effects of ADTA (25-100 mg/kg p.o.) were evaluated using two in vivo models of chemical-induced nociception during 1 h.

RESULTS

ADTA lacked cytotoxic activity (IC₅₀> 100 μM) on tumorigenic cells. In non-tumorigenic cells (HaCaT), ADTA exerted low cytotoxic effects (IC₅₀=273 μM). ADTA, at concentrations of 115 μM or higher, decreased the release of pro-inflammatory mediators. The maximum antinociceptive effects of ADTA in the acetic acid-induced abdominal constrictions by ADTA was found at 100 mg/kg (63%), whereas in the formalin test at phase 1 and phase 2, ADTA (100 mg/kg) decreased the licking time by 47 and 71%, respectively.

CONCLUSION

The results indicate that ADTA, obtained from G. glutinosum, exerts moderate in vitro anti-inflammatory and in vivo antinociceptive effects, but lacks cytotoxic effects on human cancer cells.

Suppression of nuclear factor-kappa B and mitogen-activated protein kinase signalling pathways by goshonoside-F5 extracted from Rubi Fructus

Rubi Fructus, a traditional Chinese medicine, was considered as an anti-inflammatory agent in folk medicine. In the present study, we investigated the signalling pathways involved in the anti-inflammatory effects of goshonoside-F5 (GF5), isolated from Rubi Fructus, in peritoneal macrophages and examined its therapeutic effect in a mouse endotoxic shock model. GF5 decreased NO and PGE2 production in LPS-stimulated macrophages (IC50=3.84 and 3.16μM). This effect involved the suppression of NOS-2 and COX-2 gene expression at the transcriptional level. Examination of the effects of GF5 on NF-κB signalling demonstrated that it inhibits the phosphorylation of IκB-α and IκB-β, blocking their degradation and the nuclear translocation of the NF-κB p65 subunit. Moreover, inhibition of MAPK signalling was also observed, and phosphorylation of p38 and JNK was suppressed in the presence of GF5. Inflammatory cytokines, including IL-6 and TNF-α, were down-regulated by this compound after activation with LPS (IC50=17.04 and 4.09μM). Additionally, GF5 (30 and 90mg/kg, i.p.) significantly reduced the circulating cytokine levels (IL-6 and TNF-α) and increased survival in a mouse model of endotoxemia. These results show that GF5 significantly inhibits the pro-inflammatory response induced by LPS, both in vitro and in vivo. Our results provide a strong pharmacological basis for further understanding the potential therapeutic role of GF5 in inflammatory disease and shed new light on the bioactivity of ent-labdane diterpene glucoside.

Pyrostegia venusta heptane extract containing saturated aliphatic hydrocarbons induces apoptosis on B16F10-Nex2 melanoma cells and displays antitumor activity in vivo

Background:

Pyrostegia venusta (Ker. Gawl.) Miers (Bignoniacea) is a medicinal plant from the Brazilian Cerrado used to treat leucoderma and common diseases of the respiratory system.

Objective:

To investigate the antitumor activity of P.venusta extracts against melanoma.

Materials and Methods:

The cytotoxic activity and tumor induced cell death of heptane extract (HE) from P. venusta flowers was evaluated against murine melanoma B16F10-Nex2 cells in vitro and in a syngeneic model in vivo.

Results:

We found that HE induced apoptosis in melanoma cells by disruption of the mitochondrial membrane potential, induction of reactive oxygen species and late apoptosis evidenced by plasma membrane blebbing, cell shrinkage, chromatin condensation and DNA fragmentation, exposure of phosphatidylserine on the cell surface and activation of caspase-2,-3,-8,-9. HE was also protective against singeneyc subcutaneous melanoma HE compounds were also able to induce cell cycle arrest at G2/M phases on tumor cells. On fractionation of HE in silica gel we isolated a cytotoxic fraction that contained a mixture of saturated hydrocarbons identified by ¹H NMR and GC-MS analyses. Predominant species were octacosane (C₂₈H₅₈-36%) and triacontane (C₃₀H₆₂-13%), which individually showed significant cytotoxic activity against murine melanoma B16F10-Nex2 cells in vitro and a very promising antitumor protection against subcutaneous melanoma in vivo.

Conclusion:

The results suggest that the components of the heptane extract, mainly octasane and triacontane, which showed antitumor properties in experimental melanoma upon regional administration, might also be therapeutic in human cancer, such as in the mostly epidermal and slowly invasive melanomas, such as acral lentiginous melanoma, as an adjuvant treatment to surgical excision.