Ginkgo Tree Extract Timber Antiseptic Effect

In this paper, the heartwood and bark of Ginkgo biloba were treated respectively by ether, chloroform, acetone, methanol and water for extracts. The extracts were then screened for antimicrobial activity against white-rot fungus (Coriolus versicolor and Phanerochaete chrysosporlum), brown-rot fungus (Gloeophyllum trabeum and Postia placenta) and moulds (Aspergillus niger and Trichoderma viride). The antimicrobial activity was determined by agar-well diffusion method. The study found that chloroform extract from heartwood had greater inhibition effect on white-rot fungus and brown-rot fungus. Supercritical carbon dioxide fluid extracion (SCFE-CO₂) of antimicrobial components in the heartwood of Ginkgo biloba was then used to improve the extraction rate. We discussed the effects on the extraction rate under different extraction conditions, and then identified the optimum condition was 30 MPa, 45℃and 2.5 h.Liquid-liquid extraction was used to separate the chloroform extract into 6 parts, and then Part F₅, passed through a gradient elution chromatography column, was further separated into 16 parts. All the parts were tested for antimicrobial activity against white-rot fungus, brown-rot fungus and moulds. The results showed that F₅,â…¡-1 andâ…¢-1 could inhibit white-rot fungus and brown-rot fungus.Two wood block tests were carried out, one on chloroform extract from the heartwood of Ginkgo biloba and the other on typic ACQ-D wood preservative. At the same time, scanning electron microscopy (SEM) was used to observe the growth of wood decay fungun in those two samples. The results showed that Grade I antisepsis to Coriolus versicolor and Gloeophyllum trabeum could be obtained in 1% extract solution, while the same level of antisepsis could be reached by 0.2% ACQ-D.The gas chromatograghy-mass spectrometry (GC-MS) was used to detect the chemical constituent of F₅,â…¡-1,â…¢-1 and SCFE-CO₂ extract. The results showed that phenols might exhibit antimicrobial properties. It could not be ruled out that other components in the materials at low concentration might also perform antimicrobial activity, or that the components might be coordinating with each other.