Essential oil vapours suppress the development of anthracnose and enhance defence related and antioxidant enzyme activities in avocado fruit

Anthracnose caused by Colletotrichum gloeosporioides is a major postharvest disease in avocados that causes significant losses during transportation and storage. Complete inhibition of the radial mycelia growth of C. gloeosporioides in vitro was observed with citronella or peppermint oils at 8 μL plate−1 and thyme oil at 5 μL plate−1. Thyme oil at 66.7 μL L−1 significantly reduced anthracnose from 100% (untreated control) to 8.3% after 4 days, and to 13.9% after 6 days in artificially wounded and inoculated ‘Fuerte’ and ‘Hass’ fruit with C. gloeosporioides. GC/MS analysis revealed thymol (53.19% RA), menthol (41.62% RA) and citronellal (23.54% RA) as the dominant compounds in thyme, peppermint and citronella oils respectively. The activities of defence enzymes including chitinase, 1, 3-β-glucanase, phenylalanine ammonia-lyase and peroxidase were enhanced by thyme oil (66.7 μL L−1) treatment and the level of total phenolics in thyme oil treated fruit was higher than that in untreated (control) fruit. In addition, the thyme oil (66.7 μL L−1) treatment enhanced the antioxidant enzymes such as superoxide dismutase and catalase. These observations suggest that the effects of thyme oil on anthracnose in the avocado fruit are due to the elicitation of biochemical defence responses in the fruit and inducing the activities of antioxidant enzymes. Thus postharvest thyme oil treatment has positive effects on reducing anthracnose in avocados.Post-Harvest Innovation Programme (Fresh Produce Exporter Forum, South Africa and Department of Science and Technology).http://www.elsevier.com/locate/postharvbiohb201

Influence of mangiferin on membrane bound phosphatases and lysosomal hydrolases in streptozotocin induced diabetic rats

The activities of membrane-bound ATPases and lysosomal hydrolases are altered in tissues of streptozotocin (STZ)-induced diabetic rats. Diabetes is stimulating the deterioration of membrane function and weakens the intracellular metabolism. The objective of the present study was to determine the effect of mangiferin, isolated from Salacia chinensis on membrane bound phosphatases and lysosomal hydrolases in the liver and kidney of STZ-induced diabetic rats. In our investigation, the levels of blood glucose and glycosylated haemoglobin were significantly increased in the diabetic rats. Moreover, membrane bound phosphatases and lysosomal hydrolases activities were ominously altered in the liver and kidney of STZ-induced diabetic rats. The treatment of mangiferin (40 mg/kg body weight up to 30 days) significantly brought back the activities of enzymes to near normal, when compared to the experimentally induced diabetic rats. Based on this findings, mangiferin have a substantial outcome on membrane bound phosphatases and lysosomal hydrolases in diabetic condition.Colegio de Farmacéuticos de la Provincia de Buenos Aire