ABSTRACT
A comparative study of rubber sheets obtained using formic, acetic, and smoke acid as coagulants is shown for latex obtained from native Amazonian trees and also from commercial cultivated trees. The evaluation of both processes of coagulation was carried out by spectroscopic and physical-chemical analysis, showing no differences in the rubber sheets obtained. This new method of rubber sheet preparation was introduced into Amazonian rainforest rubber tapper communities, which are actually producing in large scale. The physical-mechanical properties were similar among a large sheets made by different rubber tapper communities using this new method.
Subject(s)
Acids/chemistry , Biotechnology/methods , Latex/chemistry , Rubber , Smoke/analysis , Brazil , Spectroscopy, Fourier Transform InfraredABSTRACT
Gallic acid (1) and methyl gallate (2) were isolated from Juca, a Brazilian folk medicine, fruits of Caesalpinia ferrea MART (Leguminosae), decreased significantly the average number of papillomas per mouse in the experiment of the promoting effects of 12-O-tetra- decanoylphorbol-13-acetate (TPA) on skin tumor formation in mice initiated with 7,12-dimethylbenz[a]anthracene (DMBA).
Subject(s)
Anticarcinogenic Agents/pharmacology , Caesalpinia/chemistry , Gallic Acid/analogs & derivatives , Medicine, Traditional , Plant Extracts/pharmacology , Skin Neoplasms/chemically induced , Skin Neoplasms/prevention & control , 9,10-Dimethyl-1,2-benzanthracene/pharmacology , Animals , Anticarcinogenic Agents/chemistry , Brazil/ethnology , Female , Fruit/chemistry , Gallic Acid/isolation & purification , Gallic Acid/pharmacology , Mice , Mice, Inbred ICR , Papilloma/chemically induced , Papilloma/prevention & control , Phytotherapy , Plant Extracts/chemistry , Tetradecanoylphorbol Acetate/pharmacologyABSTRACT
The anti-tumor promoting effects of fruits of Caesalpinia ferrea MART. (Leguminosae) were tested by the in vitro Epstein-Barr virus early antigen (EBV-EA) activation assay, and its active constituents were identified as gallic acid (1) and methyl gallate (2). A total of 49 related compounds of 1 and 2 were analysed for the effects by this assay, and the structure activity relationships have been proposed. Three acetophenone derivatives, 2,6-dihydroxyacetophenone (48), 2,3,4-trihydroxyacetophenone (50) and 2,4,6-trihydroxy- acetophenone (51) were found to show potent inhibitory activity.
