Comparison of Unidenditified Sample with Located Lignosus spp.Samples Based on Geographical Origin Using FTIR and 2D-IR Correlation Spectroscopy

摘要

Lignosus sp.is a medicinal mushroom that has been used as a folk remedy for clearing 'heat',eliminating phlegm,moistening the lungs and as an anti-breast cancer agent.The genus of Lignosus consists of up to four species.It belongs to the family polyporaceae,therefore the whole mushroom is hard especially the sclerotium.They are known to grow on the ground,throughout Africa,Asia and Australia.Numerous tentative trials have been made to cultivate this mushroom.The objective of this study was to distinguish the active chemical constituents of the mushroom between one sample purchased and two samples collected from two places in Malaysia,using Fourier transform infrared (FTIR) and two-dimensional correlation Fourier transform infrared spectroscopy (2D-IR).The sample (M26/08) was purchased from a Chinese medicine shop in Kuala Lumpur and the other two samples were collected from Kuala Lipis-northern district of Pahang (M23/08),Semenyih-southern district of Selangor (M49/07).Each of these dried samples were ground into fine powder and analyzed with the entire FTIR spectra in the range of 4000-400 cm-1 and 2D-IR spectra in the region of 1800-400 cm-1 under thermal perturbation.Three samples are considered to be natural products of different origins that would have varied chemical compositions.The sample purchased from the Chinese Medicine shop was even named "Cendawan Susu Rimau"but the source has not been scientifically identified.As the other two samples (M49/07 and M23/08) were obtained from identified locations,their spectra could be used as control for the matching of the sample (M26/08).The three samples have strong absorption peaks corresponding to the stretching vibration of C=O groups.Both fresh sample M49/07 and M23/08 showed an identical peak of 1655 cm-1,whereby,M26/08 contained this stretching vibration at 1648 cm-1 may be caused by its longer storage time in the store.However,a series of peaks from 1431 cm-1 to 1203 cm-1 are very much closer between samples M26/08 and M23/08.The peak 1436 cm-1 from M49/07 showed about 5 cm-1 difference from that ofM26/08 and M23/08.The peaks from 1260 cm-1 onwards is significant of carbohydrate content including saccharides.The overall pattern from the region 1260 cm-1 to 950 cm-1 is very similar for samples M26/08 and M23/08.However M49/07 showed peaks at 1171 cm-1 and 986 cm-1 that do not appear in M26/08 and M23/08.On the other hand,M26/08 and M49/07 remain similar in peaks at 893 cm-1 as 15 cm-1 much lesser than M23/08 (908 cm-1).IR absorption peak of 890 cm-1 definitely assigned for β-D-glucan with molecular weight about 1,000,000.Even though the samples used were raw materials with small differences of region,the use of second derivative and 2D-IR spectroscopy enhanced the result to a more significant level.The spectrum of sample M26/08 was considered to be of unknown geographical origin,this was clear when a comparison was done with M49/07 and M23/08.At least,the regional pattern in original FTIR spectra of M26/08 closely matched with M23/08 from a northern province of Peninsular Malaysia.The visual and colorful 2D-IR spectra provided dynamic structural information of the chemical components analyzed and demonstrated a powerful and useful approach in the identification of unknown compounds.