Protective effect of an aqueous extract of Harpagophytum procumbens upon Escherichia coli strains submitted to the lethal action of stannous chloride.

Regardless of its lethal effects upon Escherichia coli (E. coli) cultures trough the production of free radicals (FR), stannous chloride (SnCl2) remains to be the most used reducing agent on the production of technetium-99m radiopharmaceuticals, to obtain images on nuclear medicine. Moreover, authors have reported that vegetal extracts are able to protect Escherichia coli cultures against the cytotoxicity of this agent. Harpagophytum procumbens, also known as Devil's Claw, is a plant used in folk medicine, as an analgesic and anti-inflammatory in cases of joint and back pain, on the treatment of degenerative rheumatoid arthritis, osteoarthritis, kidney inflammation and heart diseases. The presence of this extract reduced the lesive effects of SnCl2 upon E. coli AB1157 (proficient in DNA repair), BW9091 (deficient in the xthA gene) and BH110 (deficient in the xthA, nfo and fpg genes) cultures, and the deficient strains (BW9091 e BH110) were more sensible to this SnCl2 action than the proficient one. The substances in the extract could be acting as: (i) chelator of the stannous ions, avoiding the generation of FR, (ii) FR scavenger, protecting the cells against the oxidation, and/or (iii) an oxidant compound acting upon the stannous ions, reducing the SnCl2 cytotoxicity.

Guava extract (Psidium guajava) alters the labelling of blood constituents with technetium-99m.

Psidium guajava (guava) leaf is a phytotherapic used in folk medicine to treat gastrointestinal and respiratory disturbances and is used as anti-inflammatory medicine. In nuclear medicine, blood constituents (BC) are labelled with technetium-99m ((99m)Tc) and used to image procedures. However, data have demonstrated that synthetic or natural drugs could modify the labelling of BC with (99m)Tc. The aim of this work was to evaluate the effects of aqueous extract of guava leaves on the labelling of BC with (99m)Tc. Blood samples of Wistar rats were incubated with different concentrations of guava extract and labelled with (99m)Tc after the percentage of incorporated radioactivity (%ATI) in BC was determined. The results suggest that aqueous guava extract could present antioxidant action and/or alters the membrane structures involved in ion transport into cells, thus decreasing the radiolabelling of BC with (99m)Tc. The data showed significant (P<0.05) alteration of ATI in BC from blood incubated with guava extract.

A propolis extract and the labeling of blood constituents with technetium-99m.

Since ancient times propolis has been employed for many human purposes because to their favourable properties. Blood constituents labeled with technetium-99m (99mTc) have been used in nuclear medicine procedures. Some authors have reported that synthetic or natural drugs can interfere with the labeling of blood constituents with 99mTc. The aim of this work was to evaluate the action of a propolis extract on the labeling of blood elements with 99mTc. Samples of whole blood of male Wistar rats were incubated in sequence with an aqueous propolis extract at different concentrations, stannous chloride and 99mTc, as sodium pertechnetate. Blood samples were centrifuged to separate plasma and blood cells, soluble and insoluble fractions of plasma and blood cells were also separated after precipitation in trichloroacetic acid solution and centrifugation. The radioactivity was counted and the percentage of incorporated radioactivity (%ATI) for each fraction was calculated. The data obtained showed that the aqueous propolis extract used decreased significantly the %ATI in plasma proteins at higher concentration studied. Results suggest that at high concentration the constituents of this extract could alter the labeling of plasma proteins competing with same binding sites of the 99mTc on the plasma proteins or acting as antioxidant compounds.