| Agarwood. the resinous portions of Aquilaria plants, have been used as medicines and incenses in Asia. Aquilaria sinensis (Lour) Gilg.(Thymeleaceae), distributed in Fujian, Guangdong, Guangxi and Hainan provinces of China, is the major producer of agarwood in China, which had been recommended to be the grade Ⅱ protected plant in China (1999). In nature, agarwood was produced only when the plant was wounded or attacked by pathogens or insects. Black and fragrant resin produced under occasional stimulation is deposited in the stem or main branches of the trees. It is generally considered that the more the resin, the better the quality of agarwood. With increased consumption of agarwood in recent years, over-exploitation of agarwood in forest caused depletion of the natural resources. The International Union for the Conservation of Nature (IUCN) in2002classified all species of Aquilaria including A. sinensis as "vulnerable"(IUCN2002). So, improving the yield and quality of agarwood is very important now. However, the formation of agarwood has long been mysterious and associated with arcane forces, and the difference in quality between natural agarwood and artificial agarwood is not clear. There is a serious adulterants of agarwood in market.Sandalwood belongs to the Santalaceae family, highly valued for its fragrant heartwood, which contains sandal oil that is used in perfumes, medicine. In natural condition, Sandal grows very slowly; about8years begin to form heartwood, which normally takes20to25years to fully form high grade sandalwood. The species in Santalaceae family such as S. album, S. yasi, S. spicatum, S. paniculatum, S. austrocaledonicum etc can form fragrant heartwood. But, there are great quality difference among the species. This is true for S.album L. from India, Indonesia and East Timor which is the bench mark of commercial sandalwood species, owing to its high quality. S.album L is the only specie in the Pharmacopoeia of the People's Republic of China (Chinese Pharmacopoeia,2010). The variation of quality among species and the long time to form fragrant heartwood caused the quality of sandalwood vary greatly; market value difference is great, and leading to a severe mixed false situation.In order to meet the increasing demand, Aquilaria sinensis trees and sandalwood trees were widely cultivated in the south of china. However, the lack of reasonable and feasible evaluation system of quality hinders the development and utilization of agarwood and sandalwood.So, in this study, we intended to find out the quality-related evaluation index of agarwood and sandalwood by using the statistical models, and to optimize the evaluation system of agarwood and sandalwood by using thin layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS) techniques. And the rDNA ITS sequences of S. album L. introduced from India and Indonesia were amplified by PCR technology and were sequenced. The study can distinguish the fake from commercial agarwood and sandalwood, and can improve the standard of quality control. It is useful in rapid production of agarwood by artificial technology.34Samples collected from market were detected by the methods in Chinese Pharmacopoeia. Combined with the appearance and sources, the34samples can be divided into three groups by the test results:natural agarwood, artificial agarwood and fake agarwood. Follow the commercial classification criteria, the natural agarwoods were categorized into three grades. The1st grade has the best quality, the2nd grade has medium quality and the3rd grade has the poorest quality. The artificial agarwoods were categorized into three groups by the different artificial inducing technology. Three samples were artificial induced by physical methods, two samples were artificial induced by chemical methods, and three samples were artificial induced by chemical and biological joint stimulation. All the experimental results of the natural agarwoods met Chinese pharmacopoeia (edition2010) regulations, but the color reaction results of the artificial agarwoods were different from the regulations of Chinese pharmacopoeia (edition2010).An optimized TLC chromatographic fingerprint was established on the basis of TLC identification method of Chinese Pharmacopoeia.8Natural agarwoods and8artificial agarwoods were performed, and the results indicated that the TLC chromatographic fingerprint could distinguish the natural agarwoods and artificial agarwoods easily, but could not distinguish different grade in natural agarwoods and the artificial agarwoods from different artificial inducing technology.In order to distinguish the agarwoods with different quality and from different artificial inducing technology. A GC-MS chromatographic fingerprint was established. The data of8natural agarwood samples and8artificial agarwood samples in GC-MS chromatograph were studied by Genetic algorithm-Support vector machine (GA-SVM)model, two independent samples t test, correlation analysis and hierarchical clustering analysis. Specific analysis of the process are as follows:1. The relative contents of431peaks were cluster by hierarchical clustering analysis method. The clustering results indicated that the GC-MS chromatographic fingerprint could distinguish the natural agarwoods and artificial agarwoods.2. The components identified in the GC-MS chromatographic fingerprint were divided into five classes:2-(2-phenylethyl) chromanone derivatives, sesquiterpenes, aromatic compounds,aliphatic compounds and steroids. The major constituents were2-(2-phenylethyl) chromanone derivatives in all samples. The total relative contents of five compounds combined with the content of ethanol extraction were cluster by hierarchical clustering analysis method. The clustering results indicated that the different grade in natural agarwoods and the artificial agarwoods from different artificial inducing technology could be distinguished.The average total relative contents of five compounds were analyzed using two independent samples t test. It was found that the total relative contents of2-(2-phenylethyl) chromanone derivatives and sesquiterpenes had significant difference between natural agarwoods and artificial agarwoods. The correlation analysis among the total relative contents of2-(2-phenylethyl) chromanone derivatives and sesquiterpenes and the content of ethanol extraction revealed that there was a positive correlation between the total relative contents of sesquiterpenes and the content of ethanol extraction and a negative correlation between the total relative contents of2-(2-phenylethyl) chromanone derivatives and the content of ethanol extraction. There was a negative linear correlation between the total relative contents of2-(2-phenylethyl) chromanone derivatives and sesquiterpenes. Owing to sesquiterpenes was the active components of agarwood, the quality of agarwood should be related with the content of ethanol extraction and the relative content of2-(2-phenylethyl) chromone derivatives and sesquiterpenes.3. The Genetic algorithm-Support vector machine (GA-SVM)model was used to mine the data of8natural agarwood samples and8artificial agarwood samples in order to extract the the most influential ingredient which can evaluate the quality of agarwood.49ingredients extracted were analyzed using two independent samples t test. Only22ingredients had significant difference between natural agarwoods and artificial agarwoods. After correlation analysis among the relative contents of22ingredients and the content of ethanol extraction, it was found only13ingredients had significantly correlation with the content of ethanol extraction. Among the13ingredients, the relative contents of baimuxinal and spathulenol were higher than the others. The finding supposed that the relative contents of baimuxinal and spathulenol should be closely related with the quality of agarwood. In order to verify the suppose, the relative contents of baimuxinal and spathulenol combined with the content of ethanol extraction were cluster by hierarchical clustering analysis method. The clustering results indicated that the different grade in natural agarwoods and the artificial agarwoods from different artificial inducing technology could be distinguished almost.So, the optimized evaluation system of agarwood includes description, color reaction, ethanol extraction content detection and the TLC, GC-MS analysis. Four quality-related evaluation index, including the content of ethanol extraction, the relative content of2-(2-phenylethyl) chromone derivatives and sesquiterpenes, the contents of baimuxinal and spathulenol, can be used in the quality evaluation of agarwood.Then the evaluation system of agarwood with the four evaluation indexes was used in evaluating the quality of agarwood from different artificial inducing technology. A pinholes-infusion method to induce the generation of agarwood by chemically stimulated and/or inoculate combined method was established.1-2years after the artificial inoculation, resinous wood were collected and the inoculating effects were detected by the four evaluation indexes mentioned above. The results revealed that the artificial agarwood produced by chemically stimulated with formic acid combined with infected by Pestalotiopsis sp. method had higher quality than other resinous wood produced by other methods. In contrast, the artificial agarwood produced by chemically stimulated with formic acid combined with infected by Nodulisporium sp.method had poorest quality in all resinous wood.The TLC and GC-MS chromatographic fingerprint were also developed for evaluating and controlling the quality of sandalwood. Combined with literature data, some regulation was found by statistical analysis, such as there was some regularly variation of total content of santalol and α-/β-santalol percent ratio among different santalum species. So the total content of santalol and α-/β-santalol percent ratio combined with the heartwood oil content can be used to evaluate the quality of sandalwood.The optimized evaluation system of sandalwood includes description, heartwood oil content detection and the TLC, GC-MS analysis. Three quality-related evaluation index, including the content of heartwood oil, the relative content of2-(2-phenylethyl) chromone derivatives and sesquiterpenes, the total content of santalol and α-/β-santalol percent ratio can be used in the quality evaluation of sandalwood.The optimized evaluation system of sandalwood is not good in distinguishing the different species in Santalaceae family. So to develop a molecular identification of Santalum may be useful.Different fresh leaves samples of Santalum album L. introduced from India and Indonesia were collected and their rDNA ITS sequences were amplified by PCR technology and were sequenced by the Beijing Genomics institute. All Santalum reference sequences in GenBank were collected for further phylogenetic analysis. It was foud that the rDNA ITS sequence data of Santalum is stable in same species, but exist difference inter-species. The result should provide the basis for molecular identification of Santalum.The optimized evaluation system of agarwood and sandalwood, combined with evaluation indexes which were found by data mining technology are reasonable and feasible in the quality control of agarwood and sandalwood. And the evaluation systems can promote the efficient artificial techniques to increase the production and improve the quality of agarwood and sandalwood.
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