[Relationship between antibacterial activity of aloe and its anthaquinone compounds].
OBJECTIVE
To investigate the relationship between the antibacterial activity of aloe and its contents of anthaquinone compounds, measure and compale antibacterial activities of aloin and aloe-emodin, and analyse the effect of glycoside on the antibacterial activity of aloin.


METHODS
The antibacterial activities of the extracts from the outer leaf of Aloe saponaria Haw, aloin and aloe-emodin against three Gram-negative and two Gram-positive bacteria were investigated with the method of agar diffusion. The antibacterial effect of aloin on E. coli was further studied with scanning electron microscopy.


RESULTS
The antibacterial activities of aloe showed to be dependent on the dose of anthraquinone, aloin (1 g x L(-1)) exhibited higher antibacterial activity [inhibition diameter > (7. 1 +/- 0.15) mm] than Aloe-emodin (inhibition diameter < 5.0 mm), and aloin changed the morphology of E. coli and damaged the outer cell structrue.


CONCLUSIONS
Anthraquinone compounds are the active antibacterial components in aloe and aloin is the main active compound. The glycoside makes it easy for aloin to invade cells and enhances its activity.
Tian
Bing
B
Department of Applied Bioscience, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou 310029, Zhejiang, China. tianbing@zju.edu.cn
Hua
Yue-jin
YJ
Ma
Xiao-qiong
XQ
Wang
Guan-lin
GL
D000504:Aloe / Q000737:chemistry; D000880:Anthraquinones; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects; D004365:Drugs, Chinese Herbal / Q000302:isolation & purification / Q000494:pharmacology*; D004642:Emodin / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects* / Q000648:ultrastructure; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry; D011514:Proteus vulgaris / Q000187:drug effects; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects
D000880:Anthraquinones; D000900:Anti-Bacterial Agents; D004365:Drugs, Chinese Herbal; C518327:aloe emodin; D004642:Emodin; C006457:alloin