Apoptosis induction by 4-nerolidylcatechol in melanoma cell lines.

Pothomorphe umbellata, a native Brazilian plant, is popularly known to be effective in the treatment of skin lesions. This benefit is attributed to 4-nerolidylcatechol (4-NC), a compound extracted from P. umbellata. Since melanomas show prominent resistance to apoptosis and exhibit extreme chemoresistance to multiple forms of therapy, novel compounds addressing induction of cell death are worth investigating. Here, we evaluated effects on cell cycle progression and possible cytotoxic activity of 4-NC in melanoma cell lines as well as human dermal fibroblasts. Inhibitory effects on cell invasion and MMP activity were also investigated. 4-NC showed cytotoxic activity for all melanoma cell lines tested (IC50=20-40 microM, 24h for tumoral cell lines; IC50=50 microM for fibroblast cell line) associated with its capacity to induce apoptosis. Furthermore, this is the first time that 4-NC is described as an inhibitor of cell invasiveness, due mainly to a G1 cell cycle arrest and inhibition of MMP-2 activity in melanoma cell lines.

Photoprotective effect of Pothomorphe umbellata root extract against ultraviolet radiation induced chronic skin damage in the hairless mouse.

In this study we evaluated the activity of Pothomorphe umbellata root extract on hairless mice chronically exposed to UVB radiation (76.5 mJ/cm(2), 4 days per week for 22 weeks). Mouse dorsal surfaces were treated topically with 20 mg/cm(2) of a carbomer 940 gel (vehicle) with or without P. umbellata root extract to a final concentration of 0.1%, for 2 h before irradiation. Another irradiated group received no topical treatment. A fourth group received no treatment and was not irradiated. Visible skin wrinkling was evaluated using a scale ranging from 0 to 4, where 0 corresponds to no skin modification, and 4 to the maximum visual skin alteration observed in our experiments. Histological measurements were carried out on standard haematoxylin & eosin stained sections. The mean distances between the outermost surface of the epidermis (excluding the stratum corneum) and the dermal-epidermal junction were determined by morphometric analysis. These distances were statistically increased in the irradiated control groups when compared to the nonirradiated control group and to the irradiated group using P. umbellata root extract. These data demonstrate that P. umbellata may be successfully used as a topical skin-protecting agent against the deleterious effects of UV radiation.

Diel variation of larval fish abundance in the Amazon and Rio Negro.

Many streams and large rivers present higher ichthyoplankton densities at night. However, in some rivers this does not occur and larvae are equally abundant during the day. Larval drift diel variation is an important information for planning sampling programs for evaluating larval distribution and production. The aim of this study was to test whether the abundance of larval fish was different at either period. We tested it by comparing day and night densities of characiform, clupeiform and siluriform larvae during five years in the Amazon and one year in Rio Negro. We found that larvae of three species of characiform and larvae of siluriform were equally abundant during day and night in the Amazon. Conversely, the catch of Pellona spp. larvae was significantly higher during the day. In Rio Negro, however, larval abundance was higher during the night. These results imply that day samplings estimate adequately the abundance of these characiform and siluriform larvae in the Amazon, but not Pellona larvae. Evaluations of larved densities of Rio Negro will have to consider night sampling.