Bacteriostasis and fungistasis with extracts from Carya cathayensis leaves

Key words: 
• plant protection /
• Carya cathayensis /
• leaves /
• extract /
• bacteriostasis and fungistasis

Abstract: Environmentally-safe pesticides extracted from plants are paid more attention .The plants of Juglandaceae have some antibiotic substances , as flavonoid , polyphenols and terpenoid .This research was to study the bacteriostasis and fungistasis from extracts of Carya cathayensis leaves .A filter paper method was used to determine whether alcohol (95 %) extract or water (sterilized) extract from the leaves of C .cathayensis , diluted with sterile water in different concentrations (0.25 , 0.05 , 0.01 , 0.002 kgL-1), had an inhibitory effect on Staphylococcus aureus, Escherichia coli , Saccharomyces cerevisiae , Aspergillus niger , Aspergillus flavus , and Penicillium sp . Results indicated that after a 12 h culture inhibition with the alcohol extract on the six strains was significantly greater (P 0.05).After a 24 h culture , inhibition on A.flavus with both the alcohol extract and water extract was significantly greater (P 0.05) than on the other bacteria and fungi .Moreover , after 24 h culture , water extract nearly had no inhibitory effect on S .aureus and S .cerevisiae than at 12 h .After a 36 h culture , however , the alcohol extract still had a significant inhibitory effect (P 0.01) on S .aureus and S .cerevisiae .[ Ch , 2 tab . 9 ref .]