The Study On Antibacterial Active Constituents Of Perilla Frutescens

Perilla frutescens(Labiaiae), widely distributed in Asia, is a Chinese traditional and herbal drug with a long history. It consists of abundant bioactive constituents which make it a potential resource for advanced pharmaceutical utilization.The present thesis was focused on the study of antibacterial constituents of Perilla frutescens, which have been seldom reported in the past years. Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli were chosen for the antibacterial assays.Firstly, the whole fresh plants were divided into leaves, stems, roots and extracted by polar-different organic solvents respectively. The antibacterial activities of all the fractions obtained were studied and the active fractions were established: petroleum ether-soluble fraction of the leaves, ethyl acetate-soluble fractions of the leaves, stems and roots. According to the antibacterial assay, the activity of ethyl acetate-soluble fraction of the leaves is the most significant. Essential oil was extracted from the petroleum ether-soluble fraction of the leaves showed having antibacterial activity. It was demonstrated that the essential oil has significant antibacterial activity and the activity of the petroleum ether-soluble fraction is attributed to it. The constituents of the essential oil were analysized by GC-MS.10 relatively abundant components were identified on the basis of MS, among which Geranlgeraniol was found in the essential oil of Perilla frutescens leaves for the first time.Secondly, the ethyl acetate-soluble fraction of the leaves showed the most antibacterial and abundant was used for further purification, and 5 compounds of antibacterial activity were obtained through tracingthe activity and repetitive column chromatography on silica gel and Sephadex LH-20. Their structures were identified on the basis of spectral technology (MS, FT-IR, 'H-NMR, 13C-NMR, COSY, DEPT), chemical methods and comparison with related reports of literatures. These compounds are acetocaffeic acid anhydride (1), 3,3'-diethoxy rosmarinic acid (2), luteolin (3), caffeic acid (4), rosmarinic acid (5), among which 2 is a novel compound and 1 was isolated from Per ill a frutescens for the first time. They all inhibit the chosen Gram-positive and Gram-negative bacteria, and the inhibitory effects of 2, 3, 4 and 5 are prominent.Thirdly, the structure-activity relationships were established elementarily using compounds 1, 2, 4, 5 and several synthetic products by comparison of their antibacterial activities. The results suggested that phenol group is essential for the activity, especially ortho dihydroxyphenyl. In addition, the carboxyl is important to enhance the activity.