Content Of Baicalin Research Articles

Grade classification of Scutellariae Radix slices based on determination of section color and lustre

By determination the section color and lustre indexes as well as the content of baicalin in 30 batches of Scutellariae Radix slices, calculate the correlation of these two, screen the color and lustre indexes which could represent their intrinsic quality, and establish a new grade classification method based on the results. The results showed that samples met the conditions of △L≥－37, △b≥45 simultaneously were picked grade and the content of baicalin was of ≥200 mg•g⁻¹ definitely; Samples inconsistent with any one of above conditions were general grade. This research indicated that indexes of △L and △b could characterize both the color and luster of slice and intrinsic quality, so that could be used as the indexes to classify the grades of Scutellariae Radix slices accurately, easily and objectively. The research results would provide new ideas and references for grade classification of traditional Chinese medicine slices.

Distribution patterns of the contents of five biologically activate ingredients in the root of Scutellaria baicalensis

As an important herbaceous plant, Scutellaria baicalensis Georgi (Chinese skullcap) is geographically widespread and commonly used throughout the world. In the Chinese medicine market, S. baicalensis has been divided into two primary types, “Ku Qin” (WXR) and “Tiao Qin” (TST). Moreover, TST is also divided into different grades according to the diameter of roots. To explore the distribution patterns of the contents of five biologically activate ingredients (FBAI), we used six-year-old cultivated S. baicalensis and analyzed its growth characteristics as well as the quality difference among different types and diameters in roots. Throughout the entire root, we discovered that contents of the FBAI all initially increased and subsequently decreased from the top to the bottom of the roots. The baicalin content of WXR was less than that of TST. On the contrary, the contents of baicalein, wogonin, and oroxylin A in WXR were up to about two times higher than that in TST. We also found that the 0 to 40 cm part of the S. baicalensis root possessed about 87% of the root biomass and about 92% of the contents of the active ingredients.

The pharmacokinetics of Tiangou antihypertensive capsule in rat in vivo.

The aim of the study was to examine the effect of complex prescription on the pharmacokinetics of baicalin, rhynochophylline and gastrodin in Tiangou antihypertensive capsule. After administration, rat plasma was collected at different time-points. High-performance liquid chromatography was used to determine the content of baicalin, rhynochophylline and gastrodin in plasma. Two peaks occurred in the baicalin concentration-time curve. No significant difference was found for the peak concentration time (tmax) and area under concentration-time curve (AUC) of baicalin between the complex prescription and baicalin groups. The peak concentration (Cmax) of baicalin in the complex prescription group was significantly decreased, while no significant difference was found for the absorption factor (Ka) and AUC of baicalin between the complex prescription and gastrodin groups. The elimination factor (Ke) of gastrodin in the complex prescription group was significantly decreased, while the apparent volume of distribution (Vd) of gastrodin was significantly increased. No significant difference was found for AUC of baicalin between the complex prescription and rhynochophylline groups. Levels of Ka and Ke of rhynochophylline were lower in the complex prescription group while Vd was higher. Thus, complex prescription made plasma concentration-time curve more smooth. By contrast, the Tiangou antihypertensive capsule improved the distribution of baicalin, rhynochophylline and gastrodin in vivo.

Molecular characterization of flavonoid biosynthetic genes and accumulation of baicalin, baicalein, and wogonin in plant and hairy root of Scutellaria lateriflora.

Scutellaria lateriflora is well known for its medical applications because of the presence of flavanoids and alkaloids. The present study aimed to explore the molecular aspects and regulations of flavanoids. Five partial cDNAs encoding genes that are involved in the flavonoid biosynthetic pathway: phenylalanine ammonia lyase (SlPAL), cinnamate 4-hydroxylase (SlC4H), 4-coumaroyl CoA ligase (Sl4CL), chalcone synthase (SlCHS), and chalcone isomerase (SlCHI) were isolated from S. lateriflora. Organ expression analysis showed that these genes were expressed in all organs analyzed with the highest levels correlating with the richest accumulation of wogonin in the roots. Baicalin and baicalein differentially accumulated in S. lateriflora plants, with the highest concentration of baicalin and baicalein detected in the leaves and stems, respectively. Exogenous methyl jasmonate (MeJA) significantly enhanced the expression of SlCHS and SlCHI, and accumulation of baicalin (22.54 mg/g), baicalein (1.24 mg/g), and wogonin (5.39 mg/g) in S. lateriflora hairy roots. In addition, maximum production of baicalin, baicalein, and wogonin in hairy roots treated with MeJA was approximately 7.44-, 2.38-, and 2.12-fold, respectively. Light condition increased the expression level of SlCHS, the first committed step in flavonoid biosynthesis in hairy roots of S. lateriflora after 3 and 4 weeks of development compared to the dark condition. Dark-grown hairy roots contained a higher content of baicalin and baicalein than light-grown hairy roots, while light-grown hairy roots accumulated more wogonin than dark-grown hairy roots. These results may helpful for the metabolic engineering of flavonoids biosynthesis in S. lateriflora.

Predicting suitable cultivation regions of medicinal plants with Maxent modeling and fuzzy logics: a case study of Scutellaria baicalensis in China

Scientific prediction of suitable cultivation regions is an effective way for the assessment of habitat suitability and resource conservation to protect endangered medicinal plants. In recent years, the natural habitat of Scutellaria baicalensis Georgi has been degenerating and disappearing in China owing to excessive market demand of medicinal plant resource. This paper reports a new approach to predict potential suitable cultivation regions and to explore the key environmental factors affecting the content of active ingredients in S. baicalensis using integrated Maxent (maximum entropy) modeling and fuzzy logics. The modeling procedure used 275 occurrence records and baicalin contents of S. baicalensis collected through 2000–2014, and 16 Worldclim environmental factors as well as HWSD soil data. The result showed that six environmental factors (alt, prec7, prec1, bio4, bio1 and t_ph) were determined as key influential factors that mostly affect both the habitat distribution and baicalin content of S. baicalensis. The highly suitable cultivation regions of S. baicalensis mainly distribute (with probability ≥0.50) in the northeast, the north-central and the northwest of China (total 419,857 km2). The statistically significant AUC (area under the curve) value (0.952) of ROC (receiver operating characteristic) curve indicated that integrated Maxent modeling and fuzzy logics could be used to predict the potential suitable cultivation regions of medicinal plants. These results could pave the road for the habitat conservation and resource utilization of endangered medicinal plants.

Influence of different germination stage on plant biomass and active compounds of Scutellaria baicalensis germchit

This paper is aimed to study plant biomass and active compounds of Scutellaria baicalensis germchit in different five stages (from germination to transplant). The length of shoot and root, the diameter and the weight of root were determined. HPLC method was used to determine the content of active compounds (baicalin, scutellarin, wogonoside, baicalein, wogonin). According to the results, various biological indicators increased with the germination of seedling. However, the drying rate of the root declined to 27.96% from 32.90%. The contents of scutellarin and baicalein increased firstly, and then decreased. The maximums of them were 3.22,3.89 mg•g⁻¹ while the data of shoot/root was 0.35. The maximums of the contents of baicalin and wogonoside were 107.39,16.11 mg•g⁻¹ while the data of shoot/root was 0.23 and 0.06. The contents of wogonin gradually increased to the maximum of 0.88 mg•g⁻¹ while the data of shoot/root was 0.50. In conclusion, the contents of baicalin, scutellarin, wogonoside, baicalein and wogonin reached or approached the maximum at germination stage while the data of shoot/root was 0.35. The rate of shoot and root can be used as a judging index of active compounds for S. baicalensis germchit.

Study on extraction of effective components in scutellaria baicalensis Georgi by orthogonal test

Objective To investigate the optimum extraction of total flavonoids and baicalin in baical skullcap root. Methods Ultraviolet spectrophotometry was used to detect the content of total flavonoids, HPLC was used to detect the content of baicalin. With the test of extracting method, time, frequency, and adding water volume, the optimum extracting craft was determined. Results The best craft for extraction was: heating water for recirculation, setting extracting time for 1.5 h, extracting frequency for 3 times, and water volume for 8 times of baical skullcap root. Conclusion The optimized process for extraction are stable, reasonable and feasible. Key words: Scutellaria baicalensis Georgi; Extraction; Total flavonoids

The Effective Preparation of Flavonoids from Scutellaria baicalensis GEORGIby Diaion HP-20 Resin

Scutellaria baicalensis <TEX>$G_{EORGI}$</TEX> (Scutellariae Radix) has been used to clear heat and to dry dampness in the stomach or intestines, which manifests as diarrhea or dysenteric disorder. In this study, we investigated the effective preparation of active components in Scutellariae Radix using the methods of solvent extraction and absorption fractionation for the development of new functional food or pharmaceuticals. The marker substances, baicalin, baicalein, wogonoside, and wogonin were directly isolated from the Scutellariae Radix. There chemical structures were elucidated by spectroscopic analysis. The Scutellariae Radix was extracted with hot water. To enhance yield of flavonoids in Scutellariae Radix, the hot water extract was dissolved in ethanol with concentration dependent manner. The precipitates were separated using centrifugal techniques at 10,000 rpm. Supernatant liquid was applied to the HPLC for quantification of major compounds. Separately, the hot water extract was absorbed on Diaion HP-20 resin. And then, the absorbed fraction was eluted with methanol for HPLC. The contents of baicalin, baicalein, wogonoside and wogonin in different treatment methods were analyzed by HPLC. Total amount of four major components were 16.9% in 50% ethanol extract, 21.7% in 70% ethanol extract, 20.5% in 90% ethanol extract, and 39.3% in absorbed fraction of Diaion HP-20 resin. In these results, we found that resin absorption method is suitable for the extraction of enriched flavonoids from Scutellariae Radix.

Study on the chemical composition and antioxidant activity of extracts from shoot culture and regenerated plants of Scutellaria altissima L.

The flavonoid (baicalin, wogonoside, luteolin, luteolin-7-glucoside) and verbascoside contents of Scutellaria altissima in both shoot cultures, and the shoots and roots of micropropagated plants grown in the greenhouse for 12 weeks or in the field for 2 years were determined. The level of secondary metabolites was found to be strongly affected by the age and type of plant organ. A comparative analysis of S. altissima plants propagated in vitro and from seeds revealed no differences in the level of secondary metabolites when plants of the same age were studied. The antioxidant potential of methanolic extracts from shoot cultures, and the shoots and roots of S. altissima plants propagated in vitro, were evaluated using ABTS radical scavenging, FRAP metal reduction power and the lipid peroxidation test, in relation to the content of baicalin, wogonoside, verbascoside, total phenolic and total flavonoid compounds. Extracts from the roots of field-grown regenerated plants at the flowering stage were found to possess the strongest antioxidant activity. Correlation analysis revealed that the antioxidant activity of extracts correlated most closely with their total phenolic content estimated by the Folin-Ciocalteu method.

Research on quality parameters of Scutellariae Radix(formula particles) using on-line NIR in pilot with different extraction process

The on-line monitor for the changes in the content of baicalin in Scutellariae Radix formula particles during the extraction process was conducted by using near infrared spectroscopy (NIR). High performance liquid chromatography (HPLC) was used as a reference method. Kennard-Stone (KS) was used to divide sample sets, so as to compare different pretreatment methods. The synergy interval partial least squares (SiPLS) was used to screen out modeling wave band to establish partial least-squares models. The relative error method was applied to predict forecast set samples of Scutellariae Radix in three extraction phases. The results showed that the model established by Savitzky-Golay smoothing with 11 points (SG11 points) was the best, with the root mean square with cross validation (RMSECV), root mean square error of correction (RMSEC) and root mean square error of prediction (RMSEP) of baicalin of 0.092 7, 0.134 4 and 0.114 8, respectively, the determination coefficient R2 of greater than 0.99, and the relative error of baicalin content of less than 5%. This indicates that the on-line near infrared reflectance spectroscopy could be applied in on-line monitor and quality control of the extraction process of Scutellariae Radix formula particles.

Comparative pharmacokinetic investigation on baicalin and wogonoside in type 2 diabetic and normal rats after oral administration of traditional Chinese medicine Huanglian Jiedu decoction

Ethnopharmacological relevanceHuanglian Jiedu decoction (HLJDD) is used traditionally in China for the treatment of diabetes mellitus in clinical practice, which has been proved to be effective. The purpose of this study was to investigate the pharmacokinetic characteristics (especially the area under the curve, AUC) of baicalin and wogonoside in type 2 diabetic rats after oral administration of HLJDD extract and to explore its possible mechanism. Materials and methodsHLJDD extract and Radix scutellariae extract were prepared and the contents of baicalin and wogonoside contained in two extracts were assayed with high performance liquid chromatography (HPLC). Type 2 diabetic rats were induced by high fat diet and intraperitoneal injection of streptozotocin. Pharmacokinetics of baicalin and wogonoside in type 2 diabetic and normal control rats after oral administration of HLJDD extract or Radix scutellariae extract were investigated. Pharmacokinetics of baicalin in type 2 diabetic and normal rats after oral administration of pure baicalin was also investigated. ResultsThe pharmacokinetic parameters (especially AUCs) of baicalin and wogonoside in type 2 diabetic rats after oral administration of HLJDD extract were remarkably different from those in normal rats. And the alterations of the AUCs of baicalin and wogonoside in type 2 diabetic rats after oral administration of Radix scutellariae extract were similar to those after oral administration of HLJDD extract. Moreover, the increase of the AUC of baicalin in type 2 diabetic rats after oral administration of pure baicalin was similar to that after oral administration of HLJDD extract or Radix scutellariae extract. ConclusionThe pharmacokinetic behaviors of baicalin and wogonoside (especially the systemic exposure [AUCs] of baicalin and wogonoside) were significantly altered in type 2 diabetic rats after orally administrated HLJDD extract. And the increased AUCs of baicalin and wogonoside in type 2 diabetic rats after oral administration of HLJDD extract resulted from neither the effects of other herbs contained in HLJDD nor the effects of other components contained in Radix scutellariae. It might result from the effects of the pathological status of type 2 diabetes mellitus.

Effect of environmental factors on photosynthetic physiology and flavonoid constituent of Scutellaria baicalensis

To discuss the effect of environmental factors and photosynthesis on the growing of plant and the content of active components in Scutellaria baicalensis, the photosynthetic physiology index and diurnal changes of flavonoid constituent of S. Baicalensis were observed and tested in flowering and fruiting stages, and in the meantime environmental parameters were recorded. The obtained data were analyzed data by using path analysis and gray correlation analysis. The results showed that PAR and SWC were important environmental factors impacting on photosynthesis of S. baicalensis. SWC, RH and Ca were important environmental factors impacting on baicalin content. PAR, Po and Ta were important environmental factors impacting on baicalein content.

Nitric Oxide Functions as a Signal in Ultraviolet-B-Induced Baicalin Accumulation in Scutellaria baicalensis Suspension Cultures

Stress induced by ultraviolet-B (UV-B) irradiation stimulates the accumulation of various secondary metabolites in plants. Nitric oxide (NO) serves as an important secondary messenger in UV-B stress-induced signal transduction pathways. NO can be synthesized in plants by either enzymatic catalysis or an inorganic nitrogen pathway. The effects of UV-B irradiation on the production of baicalin and the associated molecular pathways in plant cells are poorly understood. In this study, nitric oxide synthase (NOS) activity, NO release and the generation of baicalin were investigated in cell suspension cultures of Scutellaria baicalensis exposed to UV-B irradiation. UV-B irradiation significantly increased NOS activity, NO release and baicalin biosynthesis in S. baicalensis cells. Additionally, exogenous NO supplied by the NO donor, sodium nitroprusside (SNP), led to a similar increase in the baicalin content as the UV-B treatment. The NOS inhibitor, Nω-nitro-l-arginine (LNNA), and NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) partially inhibited UV-B-induced NO release and baicalin accumulation. These results suggest that NO is generated by NOS or NOS-like enzymes and plays an important role in baicalin biosynthesis as part of the defense response of S. baicalensis cells to UV-B irradiation.

Simultaneous Quantitative and Qualitative Analysis of Flavonoids from Ultraviolet-B Radiation in Leaves and Roots of Scutellaria baicalensis Georgi Using LC-UV-ESI-Q/TOF/MS.

Scutellaria baicalensis Georgi is one of the most widely used traditional Chinese herbal medicines. It has been used for anti-inflammatory, anticancer, antibacterial activities, and so forth. Long-term enhanced ultraviolet-B (UV-B) radiation caused more effect on leaves than on roots of the plant. Liquid chromatography-ultraviolet detection coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (LC-UV-ESI-Q/TOF/MS) method was applied for simultaneous quantitative and qualitative analysis of flavonoids in leaves and roots of S. baicalensis by enhanced UV-B radiation. Both low-intensity radiation and high-intensity radiation were not significantly increaseing the contents of baicalin, wogonoside, and wogonin in roots. However different intensity of radiation has different effects on several flavonoids in leaves. Both low-intensity radiation and high-intensity radiation had no significant effect on contents of baicalin and tectoridin in leaves; the content of scutellarin was significantly decreased by low-intensity radiation; chrysin was detected in low-intensity radiation and high-intensity radiation, and chrysin content is the highest in low-intensity radiation, but chrysin was not detected in control group. Different changes of different flavonoids under enhanced UV-B radiation indicate that induction on flavonoids is selective by enhanced UV-B radiation.

Effects of ecological factors on secondary metabolites and inorganic elements of Scutellaria baicalensis and analysis of geoherblism

This study analyzed the effects of ecological factors on secondary metabolites of Scutellaria baicalensis using two sources: 92 individual roots of S. baicalensis from all over China, and secondary metabolites, medicinal materials and inorganic element contents obtained from the testing of 92 S. baicalensis rhizosphere soil samples. The study used environmental data from the Genuine Medicinal Material Spatial Analysis Database. Most of the chemical constituents of S. baicalensis were negatively correlated to latitude and positively correlated to temperature; generally, the contents of 21 chemical constituents were higher at low latitudes than that at high latitudes. By gradual regression analysis, it was found that the content of baicalin in S. baicalensis was negatively correlated to latitude and generally the content of inorganic elements in soil was excessively high (excluding Mg and Ca), which has a negative effect on the accumulation of chemical constituents in S. baicalensis. Based on the cluster analysis of 21 constituents, S. baicalensis from different places of origin was divided into two groups, and S. baicalensis was not genuine only in a specific small region. Within the zone from Chifeng, Inner Mongolia to Taibai, Shaanxi is suitable for accumulation of secondary metabolites of S. baicalensis and such a zone represents a suitable distribution and potential genuine producing area.

Simultaneous determination of contents of three active components in jiejia tincture by HPLC method

The objective of the study was to determine the contents of three active components in Jiejia tincture by establishing HPLC method. Test articles were prepared by ultrasonic extraction. Separation was performed using a Kromasil C18 (250 mm × 4.6 mm, 5 µm) chromatographic column, and gradient elution was performed with acetonitrile-0.3% phosphoric acid solution as the mobile phase at a volumetric flow rate of 0.80 mL/min. The contents of catechin, baicalin and berberine in Jiejia tincture were determined at the wavelength of 276 nm and a column temperature of 30 □. The results revealed that catechin showed a good linear relationship at the range of 100∼800 µg/mL (r=0.9997); baicalin showed a good linear relationship at the range of 15∼120 µg/mL (r=0.9996), and berberine at the range of 7∼56 µg/mL (r=0.9995). Their average recovery rates were 99.67% (RSD 1.01%, n=6), 98.7% (RSD 1.93%, n=6) and 100.5% (RSD 2.88%, n=6) respectively. The study concluded that the high-performance liquid chromatography established in this study was simple, accurate and reproducible, and can also be used in the determination of catechin, baicalin and berberine contents in Jiejia tincture.

Different extraction pretreatments significantly change the flavonoid contents of Scutellaria baicalensis

Context: Scutellaria baicalensis Georgi (Labiatae) is one of the most commonly used medicinal herbs, especially in traditional Chinese medicine. However, compared to many pharmacological studies of this botanical, much less attention has been paid to the quality control of the herb’s pretreatment prior to extract preparation, an issue that may affect therapeutic outcomes.Objective: The current study was designed to evaluate whether different pretreatment conditions change the contents of the four major flavonoids in the herb, i.e., two glycosides (baicalin and wogonoside) and two aglycones (baicalein and wogonin).Materials and methods: A high-performance liquid chromatography assay was used to quantify the contents of these four flavonoids. The composition changes of four flavonoids by different pretreatment conditions, including solvent, treatment time, temperature, pH value and herb/solvent ratio were evaluated.Results: After selection of the first order time-curve kinetics, our data showed that at 50 °C, 1:5 herb/water (in w/v) ratio and pH 6.67 yielded an optimal conversion rate from flavonoid glycosides to their aglycones. In this optimized condition, the contents of baicalin and wogonoside were decreased to 1/70 and 1/13, while baicalein and wogonin were increased 3.5- and 3.1-fold, respectively, compared to untreated herb.Discussion and conclusion: The markedly variable conversion rates by different pretreatment conditions complicated the quality control of this herb, mainly due to the high amount of endogenous enzymes of S. baicalensis. Optimal pretreatment conditions observed in this study could be used obtain the highest level of desired constituents to achieve better pharmacological effects.

The Establishment of the Fingerprint of Bangduling Oral Liquid by the High Performance Liquid Chromatography-Diode Array Detector

Bangduling (BDL) oral liquid, which is a new research and development herbal preparation, comprises four traditional Chinese medicines (TCM): Radix Scutellariae, Cortex Phellodendri Chinensis, Folium Isatidis, and Radix et Rhizoma Rhei. A simple, reliable and reproducible method, based on a high performance liquid chromatography-diode array detector (HPLC-DAD) method, for establishing fingerprint of complex herbal medicine BDL oral liquid was described firstly. In order to develop and validate this HPLC-DAD method, Kromasil C18 column (S-5μm, 4.6 mm × 250 mm) was used with gradient mobile phase at the column temperature of 30°C. The mobile phase was consisted of methanol and water containing 0.1% phosphoric acid. UV wavelength was set at 254 nm. Ten batches of BDL preparations were used to establish the HPLC fingerprint. In addition, the contents of baicalin in the preparations were also determined. Validation of the analytic method was evaluated by stability, precision and repeatability test. Calibration curve for baicalin showed good linearity with R2 = 0.9992. The relative standard deviations (RSDs) value of the relative retention time and peak area in the stability, precision and repeatability test, were less than 1% and 5%, respectively. The similarity of 10 batches of BDL oral liquid was more than 0.958, which showed the preparations from different batch productions were consistent. This established determination method could be efficient to the quality control of BDL oral liquid.

태음인(太陰人) 청심연자탕(淸心蓮子湯)의 동시분석 및 항비만 효과

Objectives We performed the simultaneous analysis for three compounds in Cheongsimyeonja-tang (CSYJT) and evaluated its anti-obesity effect. Methods The column for separation of three compounds was used Gemini <TEX>$C_{18}$</TEX> column and maintained at <TEX>$40^{\circ}C$</TEX>. The mobile phase for gradient elution consisted of two solvent systems. The analysis was carried out at a flow rate of 1.0 mL/min with PDA detection at 275 nm. The injection volume was <TEX>$10{\mu}L$</TEX>. 3T3-L1 preadipocytes were differentiated into adipocytes by adding insulin, dexamethasone and 3-isobutyl-1-methylxanthine (IBMX) for 8 days in the absence or presence of CSYJT. Anti-obesity effects of CSYJT were evaluated by Oil Red O staining, glycerol-3-phosphate dehydrogenase (GPDH) activity, triglyceride contents, and leptin production. Results Calibration curves were acquired with <TEX>$r^2$</TEX> >0.9999. The contents of baicalin, wogonoside and baicalein in CSYJT were 14.54-14.65 mg/g, 5.24-5.27 mg/g and 0.01-0.02 mg/g, respectively. CSYJT showed inhibitory effect on lipid accumulation and GPDH activity in the differentiated 3T3-L1 cells. Furthermore, CSYJT significantly decreased contents of triglyceride and leptin production in 3T3-L1 adipocytes. Conclusions These results will be helpful to improve quality control and anti-obesity effect of Taeeumin CSYJT.

Study on in situ intestinal absorption of baicalin contained in Tiangou Jiangya capsules

To study in situ intestinal absorption kinetics of baicalin contained in Tiangou Jiangya capsules, and the effect of different intestinal segments, pH value, drug concentration and P-gp inhibitor on the absorption. The in situ intestinal perfusion test was adopted, and HPLC method was used to determine the content of baicalin in samples at different time points. Ultra-violet (UV) spectrophotometry was used to determine the content of phenol red in samples at different time points. When pH value was at 5. 0, 6. 5, 7. 4, the absorption of baicalin was not impacted. P-gp inhibitor verapamil could enhance the absorption of baicalin. When the quality concentration of the test solution ranged between 5-20 g L -1 , the linearity of the absorption amount of baicalin increased. The absorption kinetic equation of baicalin was Y = -0. 073 7X +0. 118 7 (r = 0. 994 8) , K. 0. 073 7 h -1 , t1/2 9. 40 h. Baicalin is mainly absorbed in colon. The absorption of baicalin shows the first-order kinetics process, with the absorption mechanism of passive diffusion. Baicalin is a substrate for P-gp.