To evaluate red propolis, gum arabic and L-lysine activity on colorectal
preneoplastic lesions induced by azoxymethane (AOM).
The study featured 4 control groups (I-IV) and 4 experimental groups
(V-VIII), totaling 48 rats. Once a week for 2 weeks, animals on control
groups received saline, while animals in experimental groups received
azoxymethane (15 mg/kg i.p.). The follow up along 16 weeks included daily
oral gavage to administer water (I and V), L-lysine (150 mg/kg)(II and VI),
própolis (100mg/5ml/kg)(III and VII), or gum arabic (5ml/kg)(IV and VIII).
Was performed surgery on the animals in the end of this time in order to
collect blood for biological assays (TBARS, GSH), followed by their
sacrifice to tissue extract.
Oxidative stress (TBARS) and the number of aberrant crypt foci (ACF) in
distal colon were lower using própolis (p<0.01 for both parameters). Gum
arabic reduced preneoplastic lesions (ACF ≤ 4 crypts) on distal colon and on
the entire colon (p<0.05).
Red propolis reduced AOM-induced oxidative stress (TBARS) and total number
of ACF in the distal colon. L-lysine neither protected against nor enhanced
AOM-induced ACF. Gum arabic reduced the number of ACF.
To evaluate the effect of red propolis and
-lysine on angiogenesis and tumor growth in a new model of hamster cheek pouch inoculated with Walker 256 tumor cells.
The study consisted of two experiments with four groups each (total: 57 hamsters). In the experiment 1, the animals were inoculated with Walker tumor cells, followed by administration of test substances (red propolis 200mg/5mL/kg or
-lysine 150mg/kg) or control substances (gum arabic 5mL/kg or water 5mL/kg) for 10 days. The animals in the experiment 2 received red propolis,
-lysine, gum arabic or water at the same doses, for 33 days prior to inoculation of Walker tumor cells, followed by 10 days of treatment with the same substances. Based on single-plane images, angiogenesis was quantified (mean vascular area), in percentage, and tumor area (mm
) and perimeter (mm).
In the experiment 1, compared to animals receiving water, the mean vascular area expressed in percentage was significantly smaller in animal treated with propolis (p<0.05) and
Both red propolis and
-lysine inhibited tumor angiogenesis in the new hamster cheek pouch model when administered after tumor inoculation.
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