Technologic Studies On The Effective Fraction Of Bamboo Leaves Extraction,Separation And Purification

Nowadays, more and more herb-plant extracts with high safety, availability, efficiency, uniformity and stability have received broad attention from all over the world. Among of those, the total flavonoids extracted from bamboo leaves emerged recently. Based on a lot of domestic researches in the field of Chinese traditional medicine modernization, and combined with a long-term groundwork conducted by my supervisor in the R&D of effective fractions in bamboo leaves, this paper was designed to do next series work: taking the leaves of Phyllostachys bamboo as raw material, using microwave assisted extraction (MAE), membrane separation(MS) and Asorption - Desorption (AD) technologies, a kind of refined preparation of bamboo-leaf-total- flavonoids (BLTF) was given out, which contained total flavone glycosides in above 50% in dry base and could be used as raw-drug directly. At the same time, modern technology means was combined with advanced analysis methods; experiment capacity was scaled-up step by step; and so that the test results can be cited in practical production. The main research contents and results are as follows.Applying the MAE in the extraction of bamboo leaf effective components, and taking the total flavonoids (TF) as a responsive index, a orthogonal test with four factors and three levels, table L9(34), was conducted. Results showed that in the microwave power range of 700 to 1400W, optimum technologic parameters were ethanol concentration 40%, solid-liquid ratio 1 to 20, and extracting time 40min. However, -cyclodextrin which displayed significant solubility-enhancing effect on rutin in a mimic system had not behaved same action in this orthogonal test. Compared with by a classical Soxhlet's extracting and a industrialized heat reflux, the extracting yield of BLTF using by MAE was elevated to 150% to 160%. Furthermore, MAE exhibited particular advantages to cut extracting time, reduce organic solvent dosage and so on.A systematic study on the ultrafiltration (UF) process of pure rutin solution wasmade to discover the relationship between permeation flux and pressure, temperature, bulk velocity or pH of treated solution. Results showed that membrane permeation flux depended on the combinative effect of solute diffusion and brush action of solution flow. As regards a cross-flow system that a reversible cover layer can be formed on the dial of membrane, due to the cover-layer, the permeation is decreasing gradually in the initial stage, and then keeping at a more stable level. Generally, the permeation flux of system on this stage will increase with the enhancement of temperature and fluid speed, and decrease with the elevation of solution concentration.The effective components in bamboo-leaf-crude-extract was further condensed using by a complex membrane separation technology, which includes two stage UF and one NF operation stages. At the same time of measuring TF by spectrometry, using HPLC to detect objective products and quantify four flavone C-glycosides, in order to assure the efficiency of technology process. TF contents in three graded fractions (UF1, UF2 and NF cut off parts) were individually 31.20%, 40.20% and 25.50% in dry base, and corresponding TF reserve ratios were 12.31%, 36.61% and 22.64%; the reserve ratios on solvent were 10.90%, 25.13% and 24.51%; and the reserve ratios on four flavone-C-glycosides were10.49%, 37.86% and 30.44%. Among of those, the part of UF2 cut-off contained TF in above 40%, which was a much refined total-flavonoid preparation and can be used as dietary supplement, functional factor, cosmetic and food additives, as well as further purification for drug material. Results showed that this combined membrane separation process exhibited multiple advantages: isolation impurity, enrichment effective components and concentration liquid volume.Comparing the purifying effect of absorption, and desorption between macroreticular resin and polyamide on BLTF, the adsorption capacity for both two sorbents was 14% to 15%, the optimum action parameters were pH 7.