Study On Triterpenoids From Bamboo Bark

Bamboo bark, a traditional Chinese herb called Zhuru, is approved as 'material that can be used in healthy foods' by Ministry of Health, P. R. China, but thechemical components and quantitative parameters for quality control are stilluncertain.In the present study, the physical characteristics and chemical composition of the supercritical fluid extract from bamboo bark (coded as EZR2002), were systematically discussed and some pentacyclic triterpenoids including friedelin, lupenone and lupeol in bamboo bark were determined for the first time. Quantitative analysis of friedelin by GC was established here. Two methods -column chromatography and high speed countercurrent chromatography for separation and purification of friedelin, lupenone and lupeol were also applied. The main results were described as follows:EZR2002 was obtained from coarse powder of bamboo bark after dynamic supercritical CO2 extraction 2~5h under the condition of 50-65℃, 25-35 Mpa.EZR2002 is yellow or green-yellow powder with melting point from 74 ℃ to 79 ℃. Its IR spectrogram performed by potassium bromide showed characteristic absorption peaks in the wave number of 2917, 2849, 1716, 1463, 1382 and 720cm-1, respectively; Its UV spectrogram dissolved by spectroscopic pure CH2Cl2 with a scan range from 300 to 700nm shows a strong absorption in the wavelength of 412nm, a sub strong absorption in the wavelength of 665 nm and a weak absorption in the wavelength of 505, 535 and 605nm. EZR2002 mainly contains a group of pentacyclic triterpenoids, including friedelin, lupenone and lupeol detected by GC-MS. Total triterpenoids content was (55-75) % measured by colorimetric method using friedelin as standard , while the content of friedelin was (13.3-15.2)% and lupenone was (1.3-1.5)% % by GC using friedelin and lupenone as standard respectively in different batches of EZR2002.The quantitative analysis of the pentacyclic triterpene friedelin by GC from bamboo bark was performed. Bamboo bark was extracted in Soxhlet, hexane as extraction solvent for 8h. The chromatographic analysis was performed using HP-5 column (5%phenyl methyl siloxane, 30 m X 0.25 mm X 0.25 m) with FID detector and column temperature was programmed from 140℃ to 280℃ (holding for 22 min) at 20℃/min. The content of friedelin in bamboo bark of Phyllostachys nigra var. henonis was 0.688%. The lower limit of detectability was 1.01 g/mL.the limit of quantitation was 4.06 g/mL, and the recovery was 101.1% with relative standard deviation 2.3%. On the other hand, the extraction method has many good characteristics such as simple and effective approach, sensitive quantitative analysis and good reproducibility, so that it supplies a group of quantitative parameters for quality control of bamboo bark.4 , Friedelin, lupenone and lupeol in EZR2002 were completely separated by thin-layer chromatography(TLC) using benzene-petroleum ether (4:l,v/v) as mobile phase, iodine vapor making them visible.5 Preparative isolation and purification of triterpenoids friedelin, lupenone and lupeol from EZR2002 by column chromatography were established using hexane-ethyl acetate as mobile phase. The recovery of friedelin, lupenone and lupeol were 80.4% 71.1% and 98.0% respectively from 8.3900g EZR2002. The fraction of the separation yielded 421.90 mg of friedelin at over 98% purity 409.13 mg of friedelin at over 90% purity and 155.83 mg of friedelin at over 85% purity determined by GC.6 Preparative isolation and purification of triterpenoids friedelin, lupenone and lupeol from EZR2002 by high speed countercurrent chromatography(HSCCC) were first discussed here. In the separation with a solvent system composed of hexane-dichloromethane-acetonitrile(10:3.5:6.5,V/V), friedelin, lupenone and lupeol were eluted within 300 min from 0.3159g EZR2002 in analytical HSCCC, within 750 min from 1.0450g EZR2002 in preparative HSCCC. The recovery of friedelin, lupenone and lupeol in analytical HSCCC were 86.1%, 90.3% and 97.7%, while in preparative HSCCC were 8 1 .2%, 85.3% and 80. 1 %.