Study on Antibacterial Activities in vitro of Extracts from Solandra nitida

[Objective] To research preliminarily the antibacterial activities in vitro and the chemical composition of Solandra nitida. [Method] The total extracts,which were extracted from the leaves of this plant with 85% alcohol by method of microwave assisted extraction,were fractionated in turn by petroleum ether,ethyl acetate,n-butyl alcohol and water. The bacteriostatic circle,minimal inhibitory concentration( MIC) and minimal bactericida concentration( MBC) of the extracts against 7 species of common pathogenic bacteria were measured by disk diffusion method and microtiter plate double dilution method. The extracted mixture from leaves of this plant with water,95% ethanol and petrol ether was respectively experimented by test tube method. [Result]The result showed that the total extracts,petroleum ether phase and water phase had obvious antibacterial effect against Gram-positive bacterium such as Staphylococcus aureus,Bacillus subtilis and Staphylococcus epidermidis,but no inhibition against the Gram-negative bacterium such as Pseudomonas aeruginosa,Klebaiella pneumoniae,Salmonella paratyphi B and Escherichia coli. The leaves of Solandra nitida may contain sugar and polysaccharide and glycosides,saponins,organic acids,alkaloids,flavonoids,steroids and triterpene,cardiac glycosides. [Conclusion] The total extract from the leaves of S. nitida,which contains various bioactive substances,had antibacterial specificity against Gram-positive bacterium,and its active constituents may be in both petroleum ether phase and water phase.