Antibacterial and free-radical scavenging activities of Sonoran propolis.

AIMS: To evaluate the antibacterial and free-radical scavenging (FRS) activities of propolis collected from three different areas of Sonoran Desert in northwestern Mexico [Pueblo de Alamos (PAP), Ures (UP) and Caborca (CP)]. METHODS AND RESULTS: The antibacterial and FRS activities of Sonoran propolis were determined by the broth microdilution method and the DPPH (1,1-diphenyl-2-picrylhydracyl) assay, respectively. Propolis samples had antibacterial activity against only Gram-positive bacteria. The UP sample showed the highest antibacterial activity against Staphylococcus aureus [minimal inhibitory concentration (MIC) 100 microg ml(-1)] in a concentration-dependent manner (UP > CP > PAP). Caffeic acid phenethyl ester (CAPE), a UP propolis constituent, had very high growth-inhibitory activity towards Gram-positive bacteria, particularly against S. aureus (MIC 0.1 mmol l(-1)). To our knowledge, this is the first study showing a strong antibacterial activity of CAPE against S. aureus. Additionally, propolis CP exhibited high FRS activity (86% +/- 0.3 at 100 microg ml(-1)) comparable with those of the reference antioxidants vitamin C (87.4% +/- 1.7 at 70 micromol l(-1)) and BHT (66.07% +/- 0.76 at 140 micromol l(-1)). The propolis compounds CAPE and rutin showed high FRS activity (90.4% +/- 0.2 and 88.5% +/- 0.8 at 70 micromol l(-1), respectively). CONCLUSIONS: Sonoran propolis UP and CAPE had strong antibacterial activity against S. aureus. In addition, propolis CP showed potent FRS activity comparable with those of vitamin C and BHT. SIGNIFICANCE AND IMPACT OF THE STUDY: The strong antibacterial and antioxidant properties of Sonoran propolis and some of its constituents support further studies on the clinical applications of this natural bee product against S. aureus and several oxidative damage-related diseases.

Vitamin A deficiency and low prevalence of anemia in Yaqui Indian children in northwest Mexico.

A study of 296 school-age Yaqui Indian children (6-10 y) was conducted in 26 rural communities. Vitamin A status was determined by retinol and carotenoid serum levels according to a method described previously (IVACG, 1982). Serum retinol and carotenoids in children were analyzed according to community size. Vitamin A intake was assessed in a sub-sample by means of a 24 h recall questionnaire. Serum retinol distribution showed that 6.3% of the children were below 10 microg/100 mL (0.35 micromol/L) and 40% were in the range of 10-20 microg/100 mL (0.35-0.70 micromol/L). Differences (p < 0.02) were found between small and large communities (Median, 95% CI): 19.2 (17.1, 20.9) microg/100 mL and 22.9 (20.3, 24.1) microg/100 mL. Serum carotenoid levels were significantly higher in large than in small and medium communities: 72 (68.2, 77.8) microg/100 mL versus 62.4 (53.3, 68.2) and 62.4 (55.7, 69.6) microg/100 mL, respectively. Food staples were wheat flour tortillas, pinto beans, corn tortillas, few animal products and scarce fresh vegetables. Mean vitamin A consumption was 244+/-29 microg RE (34.9% of the US RDA). Iron status showed that only 4 children were classified as anemic, with two of them having iron deficiency anemia. Iron deficient erythropoiesis was observed in 7.8% of the children and iron depletion only in 4.4%. The Yaqui diet seems to provide adequate amounts of iron but not of vitamin A or its precursors, which renders a vitamin A status of sub-clinical deficiency that could be considered a public health problem.