<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE article  PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "http://dtd.nlm.nih.gov/publishing/3.0/journalpublishing3.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" dtd-version="3.0" xml:lang="en" article-type="research article"><front><journal-meta><journal-id journal-id-type="publisher-id">CM</journal-id><journal-title-group><journal-title>Chinese Medicine</journal-title></journal-title-group><issn pub-type="epub">2151-1918</issn><publisher><publisher-name>Scientific Research Publishing</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.4236/cm.2019.104007</article-id><article-id pub-id-type="publisher-id">CM-96532</article-id><article-categories><subj-group subj-group-type="heading"><subject>Articles</subject></subj-group><subj-group subj-group-type="Discipline-v2"><subject>Medicine&amp;Healthcare</subject></subj-group></article-categories><title-group><article-title>
 
 
  Pharmacological Investigation of “Meridian Tropism” in Three “Shen” Chinese Herbs
 
</article-title></title-group><contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Pou-Kuan</surname><given-names>Leong</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Hoi-Yan</surname><given-names>Leung</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Wing-Man</surname><given-names>Chan</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Kam-Ming</surname><given-names>Ko</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref><xref ref-type="corresp" rid="cor1"><sup>*</sup></xref></contrib></contrib-group><aff id="aff1"><addr-line>Division of Life Science, Hong Kong University of Science &amp;amp; Technology, Clear Water Bay, Hong Kong SAR, China</addr-line></aff><pub-date pub-type="epub"><day>21</day><month>11</month><year>2019</year></pub-date><volume>10</volume><issue>04</issue><fpage>121</fpage><lpage>135</lpage><history><date date-type="received"><day>27,</day>	<month>October</month>	<year>2019</year></date><date date-type="rev-recd"><day>19,</day>	<month>November</month>	<year>2019</year>	</date><date date-type="accepted"><day>22,</day>	<month>November</month>	<year>2019</year></date></history><permissions><copyright-statement>&#169; Copyright  2014 by authors and Scientific Research Publishing Inc. </copyright-statement><copyright-year>2014</copyright-year><license><license-p>This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/</license-p></license></permissions><abstract><p>
 
 
  “Meridian tropism” refers to the organ-specific biological action(s) produced 
  by a Chinese herb following its oral administration, which is analogous to the
   concept of “bioavailability” in Western medicine. In this study, we compared the in vitro and ex vivo pharmacological actions of three herbs [namely, Dangshen (DS, Codonopsis Radix), Ranshen (RS, Ginseng Radix) and Xiyangshen (XYS, Panacis Qinquifolii Ra-dix)] to validate their meridian tropism. We compared the in vitro and ex vivo pharmacological actions [
  i.e.
   the ability to increase splenocyte proliferation and adenosine triphosphate-generation capacity (ATP-GC)] of the ethanolic extracts of DS, RS and XYS to validate their meridian tropism. Results showed that DS, RS and XYS (at 30
   - 300 μg/mL) can both stimulate the proliferation of primary mouse sple
  nocytes in vitro and increase adenosine triphosphate-generation capacity (ATP-GC) in cultured Caco 2 colon epithelial cells 
  in vitro
  . Interestingly, oral administration of DS and RS (but not XYS, at 3 and 6 g/kg/day &#215; 3 consecutive days) was found to stimulate the proliferation of splenocytes ex vivo at 24 h post-treatment in mice. Similarly, DS and RS (but not XYS) increased the ATP-GC of mitochondrial fractions isolated from a small segment of mouse intestine at 48 h post-treatment. This observation is consistent with the meridian tropism of the pharmacological action of “Shen”, 
  i.e.
  , the accessibility of DS and RS (but not XYS) to the “Spleen” meridian. The comparison between the results obtained from in vitro and in vivo/ex vivo bioassays may offer a potential method for assessing meridian tropism in Chinese herbs.
 
</p></abstract><kwd-group><kwd>Codonopsis Radix</kwd><kwd> Ginseng Radix</kwd><kwd> Panacis Qinquifolii Radix</kwd><kwd> ATP-Generation Capacity</kwd><kwd> Splenocyte Proliferation</kwd></kwd-group></article-meta></front><body><sec id="s1"><title>1. Introduction</title><p>Traditional Chinese medicine theory posits that various visceral organs are functionally connected by a network of channels and collaterals (or meridians) which determines physiological functions in a holistic manner [<xref ref-type="bibr" rid="scirp.96532-ref1">1</xref>] . With this concept in mind, meridian tropism refers to a selective biological action produced by a Chinese herb on one or more target visceral organs following its oral administration [<xref ref-type="bibr" rid="scirp.96532-ref1">1</xref>] . The meridian tropism theory is therefore analogous to the pharmacokinetic concept of “bioavailability” of an herb to a target organ(s) in Western medicine. In this regard, the investigation of the mechanism underlying the organ-specific pharmacological action(s) of Chinese medicinal herbs is crucial for establishing the scientific basis (in relation to Western medicine) for the meridian tropism theory.</p><p>In TCM theory, “Qi” refers to the vital energy required for the growth and development of the human body as well as performing physiological functions through visceral organs [<xref ref-type="bibr" rid="scirp.96532-ref2">2</xref>] . Dangshen (DS, Codonopsis Radix), Ranshen (RS, Ginseng Radix) and Xiyangshen (XYS, PanacisQinquifolii Radix) are Qi-invigorating herbs, which are commonly called “Shen” in Chinese and commonly used for safeguarding health in TCM. As such, Qi-invigorating herbs have been found to reduce the expression of senescent proteins and promote cell proliferation in cultured senescent 2BS fibroblasts [<xref ref-type="bibr" rid="scirp.96532-ref3">3</xref>] . In addition, a recent study has shown that Qi-invigorating herbs can increase the energy charge in cultured rat myocytes as well as in rat skeletal muscle [<xref ref-type="bibr" rid="scirp.96532-ref4">4</xref>] . Consistent with this, a previous study in our laboratory has found that the three Qi-invigorating herbs (DS, RS and XYS) can increase adenosine triphosphate (ATP)-generation capacity (ATP-GC) in cultured H9c2 cardiomyocytes [<xref ref-type="bibr" rid="scirp.96532-ref5">5</xref>] . Interestingly, DS, RS and XYS differ in the nature of their meridian tropism, in which DS and RS but not XYS can act through the “Spleen” meridian.</p><p>In the present study, we compared the in vitro and ex vivo pharmacological actions of the three Qi-invigorating herbs (“Shen”) in an effort to validate their meridian tropism. The effects of ethanolic extracts of DS, RS and XYS on splenocyte proliferation in vitro and ex vivo were first examined. As the function of “Spleen” in TCM also relates to intestinal digestion and absorption, we also compared the effect of the three “Shen” ethanolic extracts on ATP-GC in culture Caco-2 intestinal epithelial cells in vitro and in mitochondrial fractions isolated from mouse intestine ex vivo. The chemical constituents in the “Shen” ethanolic extracts were also analyzed by high-performance liquid chromatography (HPLC) coupled with mass spectrometry (MS) in an effort to identify the chemical component(s) that might be responsible for the organ-specific Qi-invigorating action of the “Shen” ethanolic extracts.</p></sec><sec id="s2"><title>2. Materials and Methods</title><sec id="s2_1"><title>2.1. Chemical and Reagents</title><p>Eagle’s Minimum Essential Medium (EMEM) and fetal bovine serum were purchased from Gibco BRL Life Technologies (Grand Island, NY, US). RPMI1640 medium, dimethyl sulfoxide (DMSO), concanavalin A (Con A), adenosine diphosphate (ADP), adenosine triphosphate (ATP), sodium pyruvate and sodium malate were bought from Sigma Chemical Co. (St. Louis, MO, USA). Evans Blue was obtained from Santa Cruz Biotechnologies (Santa Cruz, CA, USA). All other chemicals were of analytical grade.</p></sec><sec id="s2_2"><title>2.2. Preparation of Herbal Extracts</title><p>DS, RS and XYS were purchased from a local herb dealer (Lee HoongKee Limited, HKSAR, China). The herbs were authenticated by the supplier and voucher specimens were deposited in the Division of Life Science, Hong Kong University of Science and Technology (HKUST). Each herb was extracted with 95% ethanol under reflux for 2 h, as previously described [<xref ref-type="bibr" rid="scirp.96532-ref6">6</xref>] . For the HPLC-MS analysis of “Shen” extracts, chromatographic separation was performed on a Cortecs UPLC C18 column (100 &#215; 2.1 mm, 1.6 μm) using a Dionex Ultimate 3000 UHPLC system (Thermo Fisher Scientific, San Jose, CA, USA). A Thermo LTQ Velos Pro (Thermo Fisher Scientific) multistage MS was used for detection.</p></sec><sec id="s2_3"><title>2.3. Animal Care</title><p>Adult Imprinting Control Region (ICR) female mice (8 - 10 weeks old, 20 - 25 g) were maintained under a 12-h dark/light cycle at about 22˚C and allowed food and water ad libitum in the Animal and Plant Care Facility at the Hong Kong University of Science and Technology (HKUST). All experimental protocols were approved by the University Committee on Research Practice at HKUST with the protocol number being 2,013,050.</p></sec><sec id="s2_4"><title>2.4. Isolation of Splenocytes from Mouse Spleen</title><p>Adult female ICR mice were sacrificed by cardiac excision under ketamine chloride-induced anesthesia, using a mixture of 100 mg/kg ketamine and 10 mg/kg xylazine in sterile saline. Splenocyte suspensions ere were obtained from mice as described [<xref ref-type="bibr" rid="scirp.96532-ref7">7</xref>] . Cell suspensions were re-suspended in RPMI-1640 medium supplemented with 10% FBS at a concentration of 6 &#215; 106 viable cells/mL. The viability of isolated splenocytes was determined by the Trypan Blue exclusion assay.</p></sec><sec id="s2_5"><title>2.5. Investigation of the Effects of “Shen” Ethanolic Extracts on Splenocytes in vitro</title><p>Isolated splenocytes were incubated with concanavalin A (Con A, at 4 μg/mL), Dangshen (DS, 30, 100 and 300 μg/mL), Renshen (RS, 30, 100 and 300 μg/mL) or Xiyangshen (XYS, μg/mL) for 48 h prior to conducting the cell proliferation assay. Following a 28 h incubation with Con A, DS, RS and XYS, bromodeoxyuridine (BrdU, 10 μM) was co-incubated with the splenocytes for 20 h prior to conducting the cell proliferation assay.</p></sec><sec id="s2_6"><title>2.6. Investigation on the Effects of “Shen” Ethanolic Extracts on Splenocytes ex vivo</title><p>Adult female IRC mice were intragastrically administered by gavage DS, RS or XYS ethanolic extract at doses of 3 or 6 g/kg for three consecutive days. Twenty-four hours after the last dosing, mice were sacrificed by cardiac excision under ketamine chloride anesthesia. Isolated splenocytes were cultured for 28 h and then incubated with BrdU for 20 h prior to conducting the cell proliferation assay.</p></sec><sec id="s2_7"><title>2.7. Cell Proliferation Assay</title><p>The cell proliferation of splenocytes was measured using a BrdU cell proliferation assay kit (Cell Signaling Technology Inc, MA, USA) according to the manufacturer’s instructions. The extent of splenocyte proliferation was determined by measuring absorbance at 450 nm using a Victor V3 Multi-label Counter (Perkin Elmer, Turku, Finland).</p></sec><sec id="s2_8"><title>2.8. Caco-2 Cell Culture</title><p>Caco-2 cells, which are a subclone of the original clonal cell line derived from human colon epithelial cells, were purchased from the American Tissue Culture Centre (ATCC). The cells were cultured as mono-layers in EMEM, supplemented with 10% (v/v) FBS, 100 IU/mL of penicillin, 100 μg/mL of streptomycin and 1.5 g/L of NaHCO3. All cells were grown under an atmosphere of 5% (v/v) CO2 in air at 37˚C.</p></sec><sec id="s2_9"><title>2.9. Measurement of ATP-GC in Situ</title><p>Caco-2 colon epithelial cells were seeded at a density of 6.5 &#215; 104 cells/well into 24-well microtiter plates. Following attachment, cells were incubated with “Shen” ethanolic extracts for 4 h at 37˚C. The control group was given the vehicle (DMSO) only. After the incubation, the ATP-GC assay was performed as previously described [<xref ref-type="bibr" rid="scirp.96532-ref6">6</xref>] . The ATP content generated from cells was measured by the luciferase assay (ATPlite, PerkinElmer Inc., MA). The ATP-GC of “Shen”-incubated cells (and the vehicle control group) was calculated by a two-step processing as described [<xref ref-type="bibr" rid="scirp.96532-ref8">8</xref>] . Data of “Shen” ethanolic extract-treated groups were expressed as percent of control.</p></sec><sec id="s2_10"><title>2.10. Small Intestinal Motility Following Treatment with “Shen” Ethanolic Extracts in Mice</title><p>Small intestinal motility after “Shen” ethanol extraction was measured by monitoring the migration of Evans blue from the pylorus to a region 30 cm distant, as described [<xref ref-type="bibr" rid="scirp.96532-ref9">9</xref>] .) In brief, Evans blue [at 50 mg/mL in 0.9% NaCl (w/v), 0.01 mL/g for each mouse] was intragastrically co-administered by gavage with various “Shen” ethanolic extracts (at a dose of 6 g/kg). Non-Evans Blue control animals received “Shen” ethanolic extracts (at a dose of 6 g/kg) only. At 30 min and 48 h post-treatment with Evans Blue, mice were sacrificed by cardiac excision under ketamine chloride anesthesia. The Evans blue in intestinal section was extracted and the absorbance at 600 nm was measured and quantified as area under the curve (AUC), as described [<xref ref-type="bibr" rid="scirp.96532-ref9">9</xref>] . Non-Evans Blue-treated mice were used as controls (i.e. blank). The clearance of Evans Blue at 48 h post-treatment was estimated as follows: [(Evans Blue AUC30 min − blank AUC30 min) − (Evans Blue AUC48h − blank AUC48h)]/(Evans Blue AUC 30 min − blank AUC30 min) &#215; 100%.</p></sec><sec id="s2_11"><title>2.11. Effects of “Shen” Ethanolic Extracts on ATP-GC in Mitochondrial Fractions Isolated from a Small Segment of Mouse Intestine</title><p>Female ICR mice were randomly divided into 7 groups, with 5 - 7 animals in each. To investigate the effect of “Shen” ethanolic extracts on mitochondrial ATP-GC in a small segment of intestine, mice were administered “Shen” ethanolic extracts at doses of 3 or 6 g/kg, while control animals were given vehicle (water) only. Mice were sacrificed by cardiac excision under ketamine chloride anesthesia 48 h following dosing with the “Shen” ethanolic extracts. The mitochondrial fractions of mouse intestinal epithelium were prepared as described [<xref ref-type="bibr" rid="scirp.96532-ref10">10</xref>] . The mitochondrial ATP-GC of each sample was measured as described previously [<xref ref-type="bibr" rid="scirp.96532-ref8">8</xref>] .</p></sec><sec id="s2_12"><title>2.12. Protein Assay</title><p>Protein concentrations were determined by the Bio-Rad protein assay kit (Bio-Rad, Hercules, CA), using bovine serum albumin as standard.</p></sec><sec id="s2_13"><title>2.13. Statistical Analysis</title><p>All data were expressed as mean &#177; standard derivation (SD) unless otherwise specified. The homogeneity of variance among various groups was analyzed by Levene’s test. Depending on the results of the Levene test, data were analyzed by one-way analysis of variance (one-way ANOVA) or Welch analysis of variance (Welch ANOVA). Inter-group differences were assessed by Tukey or Games-Howell analysis respectively with p &lt; 0.05.</p></sec></sec><sec id="s3"><title>3. Results</title><sec id="s3_1"><title>3.1. Differing Effects (in vitro and ex vivo) of “Shen” Ethanolic Extracts on Cell Proliferation in Isolated Mouse Splenocytes</title><p>Con A (4 μg/mL) stimulated the proliferation of cultured primary mouse splenocyte cells, with the extent of increase being 139% (<xref ref-type="fig" rid="fig1">Figure 1</xref>(a)). Incubations with DS (100 and 300 μg/mL), RS (100 and 300 μg/mL) and XYS (30 μg/mL) were found to increase cell proliferation in cultured primary mouse splenocytes, with a similar degree of stimulation (43% - 59%) (<xref ref-type="fig" rid="fig1">Figure 1</xref>(a)).</p><p>The effects of orally administered “Shen” ethanolic extracts on splenocyte proliferation were also examined ex vivo. The results showed that treatments with DS and RS (6 g/kg), but not XYS, increased the proliferation of splenocytes, with the extent of increase being 24% and 52%, respectively (<xref ref-type="fig" rid="fig1">Figure 1</xref>(b)-(d)).</p></sec><sec id="s3_2"><title>3.2. Differing Effects (in vitro and ex vivo) of “Shen” Ethanolic Extracts on ATP-GC in Cultured Caco-2 Cells and Mitochondrial Fractions Isolated from Mouse Small Intestine</title><p>Incubation with DS, RS or XYS ethanolic extracts increased ATP-GC in cultured Caco-2 intestinal epithelial cells, with the extent of stimulation being 14% and 32% (DS, at 100 and 300 μg/mL), 26% and 15% (RS, at 100 and 300 μg/mL) as well as 22%, 15% and 25% (XYS, at 30, 100, 300 μg/mL), respectively (Figures 2(a)-(c)). Small intestinal motility following oral treatment with the “Shen” extracts was also measured. Results indicated that 48 h post-treatment was sufficient to completely expel the ingested “Shen” ethanolic extract from the small intestine, as indicated by the complete clearance of the Evans blue dye (<xref ref-type="table" rid="table1">Table 1</xref>). ATP-GC of mitochondrial fractions isolated from the small intestinal mucosa in “Shen” ethanolic extract-treated mice was also measured at 48 h post-treatment. Treatments with DS and RS (6 g/kg), but not XYS, increased mitochondrial ATP-GC in the small intestinal mucosa of mice ex vivo, with the degree of stimulation being 81% and 132%, respectively (<xref ref-type="fig" rid="fig2">Figure 2</xref>(d)).</p></sec><sec id="s3_3"><title>3.3. Qualitative Analysis of Chemical Constituents in “Shen” Ethanolic Extracts</title><p>While HPLC-MS analysis of RS and XYS ethanolic extracts showed a similar chemical profile in ion chromatograms, the DS extract exhibited an ion chromatogram pattern which was different from those of RS and XYS (<xref ref-type="fig" rid="fig3">Figure 3</xref>(a)-(c)).</p></sec></sec><sec id="s4"><title>4. Discussion</title><p>According to TCM theory, the three “Shen” herbs (DS, RS and XYS) are traditionally used for Qi-invigoration, which can be viewed in terms of an up-regulation of energy status as well as the stimulation of growth and development of the human body [<xref ref-type="bibr" rid="scirp.96532-ref2">2</xref>] . A previous study in our laboratory has demonstrated that the “Shen” herbs under investigation are able to increase ATP-GC in cultured H9c2 cardiomyocytes [<xref ref-type="bibr" rid="scirp.96532-ref5">5</xref>] . Results obtained in the present study showed that the three “Shen” ethanolic extracts stimulated the proliferation of primary splenocytes in vitro and increased ATP-GC in cultured Caco 2 colon epithelial cells in vitro. Based on the “meridian tropism” theory, DS and RS but not XYS can preferentially invigorate the Qi in the “Spleen”, which, in the context of Chinese medicine, refers not only to the physiological function of the spleen but also the processes of intestinal digestion and absorption. In the present study, oral administration of DS and RS (but not XYS) was found to stimulate the proliferation of splenocytes ex vivo 24 h after the last dosing. Similarly, DS and RS (but not XYS) increased ATP-GC in mitochondrial fractions isolated at 48 h post-treatment from a small segment of mouse intestine. Since complete clearance of Evan Blue dye, co-administered with the “Shen” extracts, was observed at 48 h post-oral treatment, it seems unlikely that the DS- and RS-induced enhancement</p><table-wrap id="table1" ><label><xref ref-type="table" rid="table1">Table 1</xref></label><caption><title> The extent of clearance of Evans Blue at 48 h post-treatment. The clearance of Evans Blue at 48 h post-treatment (as compared to that of 30 min post-treatment) was estimated as described in Materials and methods</title></caption><table><tbody><thead><tr><th align="center" valign="middle"  rowspan="2"  >Absorbance at 600 nm</th><th align="center" valign="middle"  colspan="2"  >30 min post-treatment</th><th align="center" valign="middle"  colspan="2"  >48 h post-treatment</th><th align="center" valign="middle"  rowspan="2"  >Clearance (%)</th></tr></thead><tr><td align="center" valign="middle" >Blank</td><td align="center" valign="middle" >Evans Blue</td><td align="center" valign="middle" >Blank</td><td align="center" valign="middle" >Evans Blue</td></tr><tr><td align="center" valign="middle" >Dangshen</td><td align="center" valign="middle" >0.010</td><td align="center" valign="middle" >1.40 &#177; 0.41</td><td align="center" valign="middle" >0.032</td><td align="center" valign="middle" >0.030 &#177; 0.002</td><td align="center" valign="middle" >100</td></tr><tr><td align="center" valign="middle" >Renshen</td><td align="center" valign="middle" >0.005</td><td align="center" valign="middle" >1.90 &#177; 0.36</td><td align="center" valign="middle" >0.031</td><td align="center" valign="middle" >0.024 &#177; 0.003</td><td align="center" valign="middle" >100</td></tr><tr><td align="center" valign="middle" >Xiyangshen</td><td align="center" valign="middle" >0.013</td><td align="center" valign="middle" >1.60 &#177; 0.20</td><td align="center" valign="middle" >0.026</td><td align="center" valign="middle" >0.023 &#177; 0.002</td><td align="center" valign="middle" >100</td></tr></tbody></table></table-wrap><p>of mitochondrial ATP-GC is caused by a direct stimulatory action on intestinal epithelial cells prior to the isolation of mitochondrial fractions. As for XYS, it stimulated mitochondrial ATP-GC at 24 h post-treatment when the XYS ethanolic extract remained in the intestine. The inability of orally administered XYS to stimulate splenocyte proliferation ex vivo or increase mitochondrial ATP-GC in mouse intestinal epithelial cells seems to be in accordance with the meridian tropism of XYS, which describes its accessibility to the meridians of “Heart”, “Lung” and “Kidney”. Differences in the pharmacological effects produced by the three “Shen” ethanolic extracts in cell-based and animal-based assay systems can, therefore, be readily explained by the meridian tropism theory.</p><p>Ginsenosides, which belong to a group of triterpene saponins, have been shown to be active components of RS and XYS [<xref ref-type="bibr" rid="scirp.96532-ref11">11</xref>] . The protection against apoptosis in splenocytes of rats with d-galactose-induced aging [<xref ref-type="bibr" rid="scirp.96532-ref12">12</xref>] and the improvement in energy metabolism in skeletal muscle in rats with postoperative fatigue syndrome [<xref ref-type="bibr" rid="scirp.96532-ref13">13</xref>], both of which are related to the enhancement of “Spleen” function in Chinese medicine theory, suggest a “Spleen-Qi” invigorating action of ginsenosides. While HPLC-MS analysis performed in the present study did not show any differences in chemical profiles of RS and XYS ethanolic extracts, a recent study by Kim et al. have revealed notable differences between RS and XYS in terms of their chemical components [<xref ref-type="bibr" rid="scirp.96532-ref11">11</xref>] . RS possesses Rb1, Rg1 and Rb2 as major ginsenosides, a low ratio of protopanaxadiol (PPD)-groups to protopanaxatriol (PPT)-groups and a low ratio of Rb1 to Rg1, whereas XYS possesses Rb1, Re and Rd as major ginsenosides, a high ratio of PPD-groups to PPT-groups and a high ratio of Rb1 to Rg1. Intriguingly, various studies have demonstrated that the biotransformation of ginsenosides to deglycosylated ginsenosides (namely, ginsenoside compound K) is essential for producing their pharmacological actions in whole body assay conditions [<xref ref-type="bibr" rid="scirp.96532-ref14">14</xref>] . For instance, ginsenosides can be metabolized by intestinal flora into ginsenoside compound K, which is more readily absorbed in the intestine [<xref ref-type="bibr" rid="scirp.96532-ref15">15</xref>] [<xref ref-type="bibr" rid="scirp.96532-ref16">16</xref>] . Whether or not the difference in chemical composition and/or in the formation of ginsenoside compound K is a crucial determinant for producing the organ-specific pharmacological actions of RS and XYS ethanol extracts requires further investigation.</p><p>Both RS and DS ethanolic extracts exhibited pharmacological effects on the “Spleen” ex vivo irrespective of their difference in chemical composition. Active</p><p>components of DS, such as salvianolic acids, tanshinones and dihydrotanshinone, have been shown to produce immunomodulatory actions [<xref ref-type="bibr" rid="scirp.96532-ref17">17</xref>] [<xref ref-type="bibr" rid="scirp.96532-ref18">18</xref>] [<xref ref-type="bibr" rid="scirp.96532-ref19">19</xref>], which may be related to an enhancement of “Spleen” function. Given that no common chemical constituents have been identified in RS and DS [<xref ref-type="bibr" rid="scirp.96532-ref20">20</xref>] [<xref ref-type="bibr" rid="scirp.96532-ref21">21</xref>], the active component(s) in DS responsible for eliciting the organ-specific response is yet to be determined.</p><p>In conclusion, our findings indicate that the three “Shen” ethanolic extracts (DS, RS and XYS) can stimulate spleen proliferation in vitro and increase ATP-GC in Caco-2 cells in vitro. DS and RS (but not XYS) can stimulate splenocyte proliferation ex vivo and increase mitochondrial ATP-GC in mouse intestinal epithelial cells ex vivo. Despite the fact that the active components responsible for producing the organ-specific action have not as yet been identified, the results obtained from the present study are consistent with the “meridian tropism” of DS, RS and XYS. While the pharmacokinetic study of the organ distribution of chemical components in Chinese herbs has been commonly adopted for investigating the phenomenon of “meridian tropism” [<xref ref-type="bibr" rid="scirp.96532-ref22">22</xref>], the comparison between the results obtained from in vitro and in vivo/ex vivo bioassays, as shown in the present study, may offer an alternative method for validating “meridian tropism” in Chinese herbs generally.</p></sec><sec id="s5"><title>Acknowledgements</title><p>We thank Dr. Jihang Chen for his assistance in the chemical analysis.</p></sec><sec id="s6"><title>Conflicts of Interest</title><p>The authors declare no conflicts of interest regarding the publication of this paper.</p></sec><sec id="s7"><title>Cite this paper</title><p>Leong, P.-K., Leung, H.-Y., Chan, W.-M. and Ko, K.-M. (2019) Pharmacological Investigation of “Meridian Tropism” in Three “Shen” Chinese Herbs. Chinese Medicine, 10, 121-135. https://doi.org/10.4236/cm.2019.104007</p></sec></body><back><ref-list><title>References</title><ref id="scirp.96532-ref1"><label>1</label><mixed-citation publication-type="other" xlink:type="simple">Liu, P., Liu, S., Chen, G. and Wang P. (2013) Understanding Channel Tropism in Traditional Chinese Medicine in the Context of Systems Biology. Frontiers in Medicine, 7, 277-279. https://doi.org/10.1007/s11684-013-0273-3</mixed-citation></ref><ref id="scirp.96532-ref2"><label>2</label><mixed-citation publication-type="book" xlink:type="simple">Li, X., Kuang, H. and Zhao J. (2015) Why Is Qi-Invigorating Therapy in Chinese Medicine Suitable for Mitochondrial Diseases? A Bioenergetic Perspective. In: Saad, M., Ed., Complementary Therapies for the Body, Mind and Soul, InTech, Rijeka, Croatia, 243-283. https://doi.org/10.5772/60675</mixed-citation></ref><ref id="scirp.96532-ref3"><label>3</label><mixed-citation publication-type="other" xlink:type="simple">Chen, F.M., Zhao, W.K. and Xu, P.C. (2003) Comparative Study on the Regulatory Effects on Senescence Related Cell Cycle Gene Expression by TCM Principles of Tonifyingshen, Invigorating Pi Benefiting Qi, and Activating Blood Circulation. Chinese Journal of Integrated Traditional and Western Medicine, 23, 837-840.</mixed-citation></ref><ref id="scirp.96532-ref4"><label>4</label><mixed-citation publication-type="other" xlink:type="simple">Li, X.T., Zhang, J.J. and Chen, W.W. (2000)The Effects of TCM Qi-Invigorating, Qi Regulating Drugs and Polysaccharides on the Energy Charge of Rat Skeletal Muscle Cells. Journal of Beijing University of Traditional Chinese Medicine, 23, 36-38.</mixed-citation></ref><ref id="scirp.96532-ref5"><label>5</label><mixed-citation publication-type="other" xlink:type="simple">Wong, H.S., Cheung, W.F., Tang, W.L. and Ko, K.M. (2012) “Qi-Invigorating” Chinese Tonic Herbs (Shens) Stimulate Mitochondrial ATP Generation Capacity in H9c2 Cardiomyocytes in Situ and Rat Hearts ex Vivo. Chinese Medicine, 3, 101-105. https://doi.org/10.4236/cm.2012.32016</mixed-citation></ref><ref id="scirp.96532-ref6"><label>6</label><mixed-citation publication-type="other" xlink:type="simple">Leung, H.Y. and Ko, K.M. (2008) Herba Cistanche Extract Enhances Mitochondrial ATP Generation in Rat Hearts and H9c2 Cells. Pharmaceutical Biology, 46, 418-424. https://doi.org/10.1080/13880200802055883</mixed-citation></ref><ref id="scirp.96532-ref7"><label>7</label><mixed-citation publication-type="other" xlink:type="simple">Yim, T.K. and Ko, K.M. (2001) Effects of Fructus Ligustri Lucidi Extracts on Concanavalin A-Stimulated Proliferation of Isolated Murine Splenocytes. Pharmaceutical Biology, 39, 146-151. https://doi.org/10.1076/phbi.39.2.146.6258</mixed-citation></ref><ref id="scirp.96532-ref8"><label>8</label><mixed-citation publication-type="other" xlink:type="simple">Leung, H.Y., Chiu, P.Y., Poon, M.K.T. and Ko, K.M. (2005) A Yang-Invigorating Chinese Herbal Formula Enhances Mitochondrial Functional Ability and Antioxidant Capacity in Various Tissues of Male and Female Rats. Rejuvenation Research, 8, 238-247. https://doi.org/10.1089/rej.2005.8.238</mixed-citation></ref><ref id="scirp.96532-ref9"><label>9</label><mixed-citation publication-type="other" xlink:type="simple">Zou, S., Li, J., Ma, C., et al. (2015) Hawthorn Nectar Enhances Gastrointestinal Motility as Well as Stimulates Intestinal Amylase and Lipase Activities in Mice. Chinese Medicine, 6, 159-168. https://doi.org/10.4236/cm.2015.63017</mixed-citation></ref><ref id="scirp.96532-ref10"><label>10</label><mixed-citation publication-type="other" xlink:type="simple">Ojano-Dirain, C.P., Iqbal, M., Cawthon, D., et al. (2004) Determination of Mitochondrial Function and Site-Specific Defects in Electron Transport in Duodenal Mitochondria in Broilers with Low and High Feed Efficiency. Poultry Science, 83, 1394-1403. https://doi.org/10.1093/ps/83.8.1394</mixed-citation></ref><ref id="scirp.96532-ref11"><label>11</label><mixed-citation publication-type="other" xlink:type="simple">Kim, D.H. (2012) Chemical Diversity of Panax Ginseng, Panax quinquifolium, and Panax notoginseng. Journal of Ginseng Research, 36, 1-15. 
https://doi.org/10.5142/jgr.2012.36.1.1</mixed-citation></ref><ref id="scirp.96532-ref12"><label>12</label><mixed-citation publication-type="other" xlink:type="simple">Sun, J., Zhang, L., Zhang, J., Ran, R., Shao, Y., Li, J., et al. (2018) Protective Effects of Ginsenoside Rg1 on Splenocytes and Thymocytes in an Aging Rat Model Induced by d-Galactose. International Immunopharmacology, 58, 94-102. 
https://doi.org/10.1016/j.intimp.2018.03.017</mixed-citation></ref><ref id="scirp.96532-ref13"><label>13</label><mixed-citation publication-type="other" xlink:type="simple">Tan, S.J., Li, N., Zhou, F., Dong, Q.T., Zhang, X.D., Chen, B.C., et al. (2014) Ginsenoside Rb1 Improves Energy Metabolism in the Skeletal Muscle of an Animal Model of Postoperative Fatigue Syndrome. Journal of Surgical Research, 191, 344-349. 
https://doi.org/10.1016/j.jss.2014.04.042</mixed-citation></ref><ref id="scirp.96532-ref14"><label>14</label><mixed-citation publication-type="other" xlink:type="simple">Yang, X.D., Yang, Y.Y., Ouyang, D.S. and Yang, G.P. (2015) A Review of Biotransformation and Pharmacology of Ginsenoside Compound K. Fitoterapia, 100, 208-220. https://doi.org/10.1016/j.fitote.2014.11.019</mixed-citation></ref><ref id="scirp.96532-ref15"><label>15</label><mixed-citation publication-type="other" xlink:type="simple">Akao, T., Kanaoka, M. and Kobashi, K. (1998) Appearance of Compound K, a Major Metabolite of Ginsenoside Rb1 by Intestinal Bacteria, in Rat Plasma after Oral Administration—Measurement of Compound K by Enzyme Immunoassay. Biological and Pharmaceutical Bulletin, 21, 245-249. https://doi.org/10.1248/bpb.21.245</mixed-citation></ref><ref id="scirp.96532-ref16"><label>16</label><mixed-citation publication-type="other" xlink:type="simple">Akao, T., Kida, H., Kanaoka, M., Hattori, M. and Kobashi, K. (1998) Intestinal Bacterial Hydrolysis Is Required for the Appearance of Compound K in Rat Plasma after Oral Administration of Ginsenoside Rb1 from Panax ginseng. Journal of Pharmacy and Pharmacology, 50, 1155-1160. 
https://doi.org/10.1111/j.2042-7158.1998.tb03327.x</mixed-citation></ref><ref id="scirp.96532-ref17"><label>17</label><mixed-citation publication-type="other" xlink:type="simple">Xia, Z.B., Yuan, Y.J., Zhang, Q.H., Li, H., Dai, J.L. and Min, J.K. (2018) Salvianolicacid B Suppresses Inflammatory Mediator Levels by Downregulating NF-κB in a Rat Model of Rheumatoid Arthritis. Medical Science Monitor, 24, 2524-2532. 
https://doi.org/10.12659/MSM.907084</mixed-citation></ref><ref id="scirp.96532-ref18"><label>18</label><mixed-citation publication-type="other" xlink:type="simple">Yu, Q., Chen, H., Sheng, L., Liang, Y. and Li, Q. (2014) Sodium Tanshinone IIA Sulfonate Prolongs the Survival of skin Allografts by Inhibiting Inflammatory Cell Infiltration and T Cell Proliferation. International Immunopharmacology, 22, 277-284. https://doi.org/10.1016/j.intimp.2014.07.002</mixed-citation></ref><ref id="scirp.96532-ref19"><label>19</label><mixed-citation publication-type="other" xlink:type="simple">Li, X., Yang, J.H., Jin, Y., et al. (2015) 15,16-Dihydrotanshinone I Suppresses IgE-Ag Stimulated Mouse Bone Marrow-Derived Mast Cell Activation by Inhibiting Syk kinase. Journal of Ethnopharmacology, 169, 138-144. 
https://doi.org/10.1016/j.jep.2015.04.022</mixed-citation></ref><ref id="scirp.96532-ref20"><label>20</label><mixed-citation publication-type="other" xlink:type="simple">Ru, W., Wang, D., Xu, Y., et al. (2015) Chemical Constituents and Bioactivities of Panax ginseng (C. A. Mey.). Drug Discoveries and Therapeutics, 9, 23-32. 
https://doi.org/10.5582/ddt.2015.01004</mixed-citation></ref><ref id="scirp.96532-ref21"><label>21</label><mixed-citation publication-type="other" xlink:type="simple">Su, C.Y., Ming, Q.L., Rahman, K., Han, T. and Qin, L.P. (2015) Salvia Miltiorrhiza: Traditional Medicinal Uses, Chemistry, and Pharmacology. Chinese Journal of Natural Medicines, 13, 163-182. https://doi.org/10.1016/S1875-5364(15)30002-9</mixed-citation></ref><ref id="scirp.96532-ref22"><label>22</label><mixed-citation publication-type="other" xlink:type="simple">Zhao, Y., Li, Y., Wang, X. and Sun, W. (2008) The Experimental Study of Cortex Eucommiae on Meridian Tropsim: The Distribution Study of Aucubin in Rat Tissues. Journal of Pharmaceutical and Biomedical Analysis, 46, 368-373. 
https://doi.org/10.1016/j.jpba.2007.09.028</mixed-citation></ref></ref-list></back></article>