Protopanaxatriol-type Saponins Research Articles

Structural Characters and Pharmacological Activity of Protopanaxadiol-Type Saponins and Protopanaxatriol-Type Saponins from Ginseng.

Ginseng has a long history of drug application in China, which can treat various diseases and achieve significant efficacy. Ginsenosides have always been deemed important ingredients for pharmacological activities. Based on the structural characteristics of steroidal saponins, ginsenosides are mainly divided into protopanaxadiol-type saponins (PDS, mainly including Rb1, Rb2, Rd, Rc, Rh2, CK, and PPD) and protopanaxatriol-type saponins (PTS, mainly including Re, R1, Rg1, Rh1, Rf, and PPT). The structure differences between PDS and PTS result in the differences of pharmacological activities. This paper provides an overview of PDS and PTS, mainly focusing on their chemical profile, pharmacokinetics, hydrolytic metabolism, and pharmacological activities including antioxidant, antifatigue, antiaging, immunodulation, antitumor, cardiovascular protection, neuroprotection, and antidiabetes. It is intended to contribute to an in-depth study of the relationship between PDS and PTS.

The anti-aging mechanism of ginsenosides with medicine and food homology.

With the acceleration of global aging and the rise in living standards, the achievement of healthy aging is becoming an imperative issue globally. Ginseng, a medicinal plant that has a long history of dietary intake and remarkable medicinal value, has become a research hotspot in the field of food and medicine. Ginsenosides, especially protopanaxadiol-type saponins and protopanaxatriol-type saponins, are among the most important active ingredients in ginseng. Ginsenosides have been found to exhibit powerful and diverse pharmacological activities, such as antiaging, antitumor, antifatigue and immunity enhancement activities. Their effects in antiaging mainly include (1) promotion of metabolism and stem cell proliferation, (2) protection of skin and nerves, (3) modulation of intestinal flora, (4) maintenance of mitochondrial function, and (5) enhancement of telomerase activity. The underlying mechanisms are primarily associated with the intervention of the signaling pathways in apoptosis, inflammation and oxidative stress. In this review, the mechanism of action of ginsenosides in antiaging as well as the potential values of developing ginsenoside-based functional foods and antiaging drugs are discussed.

Quantitative Comparison and Chemical Profile of Different Botanical Parts of Panax notoginseng From Different Regions.

The root of Panax notoginseng, a highly valued medicine and functional food, is the main part used for medicinal purposes. However, the stems and leaves are also used in practice. To provide a chemical basis for various uses, a quantitative comparison of 18 saponins using a non-targeted metabolomics approach was established, so as to investigate the chemical profiles of the different parts of P. notoginseng. The established strategy revealed that roots and stems, with their similar chemical characteristics, consisted mainly of protopanaxatriol-type saponins, whereas protopanaxadiol-type saponins were principally present in the leaves. Multivariate analysis further suggested that the quality of the stems and leaves of P. notoginseng was significantly affected by its geographical origin. Furthermore, 52 constituents (26 non-volatile and 26 volatile) were identified as potential markers for discriminating between different parts of the plant. Taken together, the study provides comprehensive chemical evidence for the rational application and exploitation of different parts of P. notoginseng.

Prevention Effect of Protopanaxadiol-Type Saponins Saponins and Protopanaxatriol-Type Saponins on Myelosuppression Mice Induced by Cyclophosphamide.

Ginsenosides from ginseng are used as a therapeutic agent for various diseases. They enhance the immunomodulatory effect in cyclophosphamide (CP)-treated tumor disease. The structural characteristics of steroidal saponins are mainly divided into protopanaxadiol-type saponin (PDS) and protopanaxatriol-type saponin (PTS). At present, few researchers have studied which kind of saponin plays a more important role, thus, we compared the prevention effect of PDS and PTS on myelosuppression mice induced by CP. The components and contents of saponin and monosaccharide were analyzed by using ultra high performance liquid chromatography-charged aerosol detector (UPLC-CAD) and reversed phase-high performance liquid chromatography (RP-HPLC), respectively. Thirty-two mice were randomly divided into four groups, including control, model (CP), CP+PDS, and CP+PTS. The mice were orally administered with PDS or PTS for 28 days and then injected with CP saline solution on 25, 26, 27, and 28 days at a dose of 50 mg × kg−1. After the end of modeling, the whole blood of mice from the ophthalmic venous plexus was collected to detect routine blood tests, inflammatory cytokines, and hematopoiesis-related cytokines. Cell cycle and the apoptosis of bone marrow in the right femur were detected. The spleen and thymus were used to calculate the organ index and histological examination, and splenocytes were used to detect the percentage of CD4+ and CD25+ T cells. In the saponins analysis, PDS mainly included the Rb1, Rc, Rb2, and Rd of protopanaxadiol-type ginsenosides (accounted for 91.64%), and PTS mainly included the Re, Rg1, and Rf of protopanaxatriol-type ginsenosides (accounted for 75.46%). The animal results showed that both PDS and PTS improved the most indicators of myelosuppression mice induced by CP, including increased weight, blood cell numbers, hematopoiesis-related cytokines, and inflammatory cytokines; promoted the cell cycle of bone marrow and inhibited the apoptosis of bone marrow; elevated the spleen and thymus indexes and CD4+ count of splenocytes. The prevention effect of PDS was better than PTS in some indicators, such as red blood cells, hemoglobin, interleukin (IL)-1β, IL-4, IL-10, tumor necrosis factor-α, CD4+, and thymus index. These results suggest both PDS and PTS can prevent myelosuppression of mice induced by CP. Meanwhile, PDS and its metabolite showed higher bioavailability and bioactivity compared with PTS.

High-level sustainable production of the characteristic protopanaxatriol-type saponins from Panax species in engineered Saccharomyces cerevisiae

The Chinese medicinal plant Panax notoginseng has been traditionally used to activate blood flow and circulation, and to prevent blood stasis. P. notoginseng contains protopanaxatriol (PPT)-type saponins as its main active compounds, thus distinguishing it from the other two famous Panax species, P. ginseng and P. quinquefolius. Ginsenoside Rg1 (Rg1), notoginsenoside R1 (NgR1), and notoginsenoside R2 (NgR2) are three major PPT-type saponins in P. notoginseng and possess potential cardiovascular protection activities. However, their use in medical applications has long been hampered by the lack of sustainable and low-cost industrial-scale preparation methods. In this study, a PPT-producing yeast chassis strain was designed and constructed based on a previously constructed and optimized protopanaxadiol (PPD)-producing Saccharomyces cerevisiae strain, and further optimized by systemically engineering and optimizing the expression level of its key P450 biopart. Rg1-producing yeast strains were constructed by introducing PgUGT71A53 and PgUGT71A54 into the PPT chassis strain. The fermentation titer of Rg1 reached 1.95 g/L. A group of UDP-glycosyltransferases (UGT) from P. notoginseng and P. ginseng were characterized, and were found to generate NgR1 and NgR2 by catalyzing the C6–O-Glc xylosylation of Rg1 and Rh1, respectively. Using one of these UGTs, PgUGT94Q13, and the previously identified PgUGT71A53 and PgUGT71A54, the biosynthetic pathway to produce saponins NgR1 and NgR2 from PPT could be available. The NgR1 cell factory was further developed by introducing PgUGT94Q13 and a heterologous UDP-xylose biosynthetic pathway from Arabidopsis thaliana into the highest Rg1-producing cell factory. The NgR2-producing cell factory was constructed by introducing PgUGT71A54, PgUGT94Q13, and the UDP-xylose biosynthetic pathway into the PPT chassis. De novo production of NgR1 and NgR2 reached 1.62 g/L and 1.25 g/L, respectively. Beyond the realization of artificial production of the three valuable saponins Rg1, NgR1, and NgR2 from glucose, our work provides a green and sustainable platform for the efficient production of other PPT-type saponins in engineered yeast strains, and promotes the industrial application of PPT-type saponins as medicine and functional foods.

Integrated Chemical and Transcriptomic Analysis Reveals the Distribution of Protopanaxadiol- and Protopanaxatriol-Type Saponins in Panax notoginseng.

Panax notoginseng is famous for its important therapeutic effects and commonly used worldwide. The active ingredients saponins have distinct contents in different tissues of P. notoginseng, and they may be related to the expression of key genes in the synthesis pathway. In our study, high-performance liquid chromatography results indicated that the contents of protopanaxadiol-(Rb1, Rc, Rb2, and Rd) and protopanaxatriol-type (R1, Rg1, and Re) saponins in below ground tissues were higher than those in above ground tissues. Clustering dendrogram and PCA analysis suggested that the below and above ground tissues were clustered into two separate groups. A total of 482 and 882 unigenes were shared in the below and above ground tissues, respectively. A total of 75 distinct expressions of CYPs transcripts (RPKM ≥ 10) were detected. Of these transcripts, 38 and 37 were highly expressed in the below ground and above ground tissues, respectively. RT-qPCR analysis showed that CYP716A47 gene was abundantly expressed in the above ground tissues, especially in the flower, whose expression was 31.5-fold higher than that in the root. CYP716A53v2 gene was predominantly expressed in the below ground tissues, especially in the rhizome, whose expression was 20.1-fold higher than that in the flower. Pearson’s analysis revealed that the CYP716A47 expression was significantly correlated with the contents of ginsenoside Rc and Rb2. The CYP716A53v2 expression was associated with the saponin contents of protopanaxadiol-type (Rb1 and Rd) and protopanaxatriol-type (R1, Rg1, and Re). Results indicated that the expression patterns of CYP716A47 and CYP716A53v2 were correlated with the distribution of protopanaxadiol-type and protopanaxatriol-type saponins in P. notoginseng. This study identified the pivotal genes regulating saponin distribution and provided valuable information for further research on the mechanisms of saponin synthesis, transportation, and accumulation.

Simultaneous Determination of Eight Ginsenosides in Rat Plasma by Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry: Application to Their Pharmacokinetics.

A high-performance liquid chromatography–electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was successfully developed and validated for the identification and determination of eight ginsenosides: ginsenoside Rg1 (1); 20(S)-ginsenoside Rh1 (2); 20(S)-ginsenoside Rg2 (3); 20(R)-ginsenoside Rh1 (4); 20(R)-ginsenoside Rg2 (5); ginsenoside Rd (6); 20(S)-ginsenoside Rg3 (7); and 20(R)-ginsenoside Rg3 (8) in rat plasma. The established rapid method had high linearity, selectivity, sensitivity, accuracy, and precision. The method has been used successfully to study the pharmacokinetics of abovementioned eight ginsenosides for the first time. After an oral administration of total saponins in the stems-leaves of Panax ginseng C. A. Meyer (GTSSL) at a dose of 400 mg/kg, the ginsenosides 6, 7, and 8, belonging to protopanaxadiol-type saponins, exhibited relatively long tmax values, suggesting that they were slowly absorbed, while the ginsenosides 1–5, belonging to protopanaxatriol-type saponins, had different tmax values, which should be due to their differences in the substituted groups. Compounds 2 and 4, 3 and 5, 7 and 8 were three pairs of R/S epimerics at C-20, which was interesting that the t1/2 of 20(S)-epimers were always longer than those of 20(R)-epimers. This pharmacokinetic identification of multiple ginsenosides of GTSSL in rat plasma provides a significant basis for better understanding the clinical application of GTSSL.

Minor dehydrogenated and cleavaged dammarane-type saponins from the steamed roots of Panax notoginseng

Nine new minor dehydrogenated and cleavaged dammarane-type triterpenoid saponins, namely notoginsenosides ST6-ST14 (1–9) were isolated from the steamed roots of Panax notoginseng, together with 14 known ones. Among them, 5–7 and 21–22 were protopanaxadiol type and the left 18 compounds, including 1–4, 8–20, and 23 were protopanaxatriol type saponins. Their structures were identified by extensive analysis of MS, 1D and 2D NMR spectra, and acidic hydrolysis. Resulted from the side chain cleavage, the new saponins 1 and 2 featured in a ketone group at C-25, and 3–5 had an aldehyde unit at C-23. The known saponins 12, 16 and 18 displayed the enhancing potential of neurite outgrowth of NGF-mediated PC12 cells at a concentration of 10μM, while 20 exhibited acetyl cholinesterase inhibitory activity, with IC50 value of 13.97μM.

Protopanaxatriol metabolites identified by LC-MS/MS after oral administration in mice

20(S)-Protopanaxatriol (Ppt), a well-known end metabolite of protopanaxatriol-type saponins, has recently been reported to have the same bioactivity as its prototype. Whether or not Ppt could be further metabolized into other compounds in vivo is still unknown. The present study is aimed to determine the structures of Ppt metabolites in mice. The metabolites were produced by intragastric gavage of Ppt in mice. The homogenate of small intestine was used for analysis after solid phase extraction. The metabolic profile of Ppt was investigated by using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), which were also used to identify the structures of metabolites. Accurate mass measurement using LC-time of flight MS was applied to determine the element composition of metabolites and thus to confirm their proposed structures. One Phase I and three Phase II metabolites were detected at 1 h, 5 h, and 10 h after administration of Ppt, which were the same at the three time points. The Phase I metabolic changes observed included dehydrogenation and hydroxylation of the steroid-like structure, as well as formation of an ester bond at C-20 of the side chain. The Phase II metabolites involved conjugation to aminoethylsulfonic acid after hydrolysis of the ester bond. A possible biotransformation pathway was proposed. Ppt yielded four metabolites in vivo, and 1 h was enough to complete the biotransformation process of Ppt.

Comparison of the antiobesity effects of the protopanaxadiol‐ and protopanaxatriol‐type saponins of red ginseng

A previous study demonstrated that ginseng crude saponins prevent obesity induced by a high-fat diet in rats. Ginseng crude saponins are known to contain a variety of bioactive saponins. The present study investigated and compared the antiobesity activity of protopanaxadiol (PD) and protopanaxatriol (PT) type saponins, major active compounds isolated from crude saponins. Male 4-week-old Sprague-Dawley rats were fed with normal diet (N) or high-fat diet (HF). After 5 weeks, the HF diet group was subdivided into the control HF diet, HF diet-PD and HF diet-PT group (50 mg/kg/day, 3 weeks, i.p.). Treatment with PD and PT in the HF diet group reduced the body weight, total food intake, fat contents, serum total cholesterol and leptin to levels equal to or below the N diet group. The hypothalamic expression of orexigenic neuropeptide Y was significantly decreased with PD or PT treatment, whereas that of anorexigenic cholecystokinin was increased, compared with the control HF diet group. In addition, PD type saponins had more potent antiobesity properties than PT saponins, indicating that PD-type saponins are the major components contributing to the antiobesity activities of ginseng crude saponins. The results suggest that the antiobesity activity of PD and PT type saponins may result from inhibiting energy gain, normalizing hypothalamic neuropeptides and serum biochemicals related to the control of obesity.

Microbial Transformation of 20(S)-Protopanaxatriol-Type Saponins by Absidia coerulea

Three 20(S)-protopanaxatriol-type saponins, ginsenoside-Rg1 (1), notoginsenoside-R1 (2), and ginsenoside-Re (3), were transformed by the fungus Absidia coerulea (AS 3.3389). Compound 1 was converted into five metabolites, ginsenoside-Rh4 (4), 3beta,2beta,25-trihydroxydammar-(E)-20(22)-ene-6-O-beta-D-glucopyranoside (5), 20(S)-ginsenoside-Rh1 (6), 20(R)-ginsenoside-Rh1 (7), and a mixture of 25-hydroxy-20(S)-ginsenoside-Rh1 and its C-20(R) epimer (8). Compound 2 was converted into 10 metabolites, 20(S)-notoginsenoside-R2 (9), 20(R)-notoginsenoside-R2 (10), 3beta,12beta,25-trihydroxydammar-(E)-20(22)-ene-6-O-beta-D-xylopyranosyl-(1-->2)-beta-D-glucopyranoside (11), 3beta,12beta-dihydroxydammar-(E)-20(22),24-diene-6-O-beta-D-xylopyranosyl-(1-->2)-beta-D-glucopyranoside (12), 3beta,12beta,20,25-tetrahydroxydammaran-6-O-beta-D-xylopyranosyl-(1-->2)-beta-D-glucopyranoside (13), and compounds 4-8. Compound 3 was metabolized to 20(S)-ginsenoside-Rg2 (14), 20(R)-ginsenoside-Rg2 (15), 3beta,12beta,25-trihydroxydammar-(E)-20(22)-ene-6-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (16), 3beta,12beta-dihydroxydammar-(E)-20(22),24-diene-6-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (17), 3beta,12beta,20,25-tetrahydroxydammaran-6-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside (18), and compounds 4-8. The structures of five new metabolites, 10-13 and 16, were established by spectroscopic methods.

Structure and biological activity of protopanaxatriol-type saponins from the roots of Panax notoginseng

The further purification of the total saponins from the roots of Panax notoginseng by using ordinary and reversed-phase silica-gel, as well as Sephadex LH-20 chromatography afford seven adjuvant active protopanaxatriol-type saponins (PTS), ginsenosides-Rh 1 (Rh 1),-Rh 4 (Rh 4),-Rg 1 (Rg 1),-Re (Re), notoginsenosides-R 1 (R 1),-R 2 (R 2),-U (U). These saponins were evaluated for their haemolytic activities and adjuvant potentials on the cellular and humoral immune responses of ICR mice against ovalbumin (OVA). The effect of the substitution pattern of these PTS on their biological activities was investigated and structure-activity relationships were established. Among seven PTS, the haemolytic activity of Rh 1 was higher than that of other six compounds ( p < 0.001) The HD 50 values of Rh 4 and U were significantly bigger than those of R 2, Rg 1 and Re ( p < 0.05 or p < 0.01). Seven PTS could significantly increase the concanavalin A (Con A)-, lipopolysaccharide (LPS)- and OVA-induced splenocyte proliferation in the OVA-immunized mice ( p < 0.01 or p < 0.001). The OVA-specific IgG, IgG1, IgG2a and IgG2b antibody levels in serum were also significantly enhanced by seven PTS compared with OVA control group ( p < 0.01 or p < 0.001). The structure-activity relationship studies suggested that the number, the length and the position of sugar side chains, and the type of glucosyl group in the structure of PTS could not only affect their haemolytic activities and adjuvant potentials, but have significant effects on the nature of the immune responses. The information about this structure/function relationship might be useful for developing semisynthetic tetracyclic triterpenoid saponin derivatives with immunological adjuvant activity, as well as a reference to the distribution of the functional groups composing the saponin molecule.

Proof of the Mysterious Efficacy of Ginseng: Basic and Clinical Trials: Suppression of Adrenal Medullary Function In Vitro by Ginseng

The root of Panax ginseng C.A. MEYER has been reported to have an anti-stress action. Therefore, the effects of ginseng components on functions of adrenal medulla, which is one of the most important organs responsive to stress, were investigated in vitro. First, the components of ginseng were mainly divided into two fractions, that is, the saponin-rich and non-saponin fractions. The saponin-rich fraction greatly reduced the secretion of catecholamines from bovine adrenal chromaffin cells stimulated by acetylcholine (ACh), whereas the nonsaponin fraction did not affect it at all. The protopanaxatriol-type saponins inhibited the ACh-evoked secretion much more strongly than the protopanaxadiol-type. On the other hand, the oleanane-type saponin, ginsenoside-Ro, had no such effect. Recent reports have demonstrated that the saponins in ginseng are metabolized and absorbed in digestive tracts following oral administration of ginseng. All of the saponin metabolites greatly reduced the ACh-evoked secretion. M4 was the most effective inhibitor among the metabolites. M4 blocked ACh-induced Na+ influx and ion inward current into the chromaffin cells and into the Xenopus oocytes expressing human α3β4 nicotinic ACh receptors, respectively, suggesting that the saponin metabolites modulate nicotinic ACh receptors followed by the reduction of catecholamine secretion. It is highly possible that these effects of ginsenosides and their metabolites are associated with the anti-stress action of ginseng.

The Inhibitory Effects of Ginsenosides on Protein Tyrosine Kinase Activated by Hypoxia/Reoxygenation in Cultured Human Umbilical Vein Endothelial Cells

27 individual ginsenosides and aglycones, together with five extracts from ginseng roots, ginseng leaves, American ginseng roots, American ginseng leaves and non-saponin fraction from roots of Panax ginseng, were tested for their effects on protein tyrosine kinase (PTK) activation induced by an in vitro hypoxia/reoxygenation (H/R) model in cultured human umbilical vein endothelial cells (HUVEC). The results indicated that ginsenoside-Rb1 (3), -Rd (7), -Ra1 (1) and -Ro (27) showed significant inhibitory effects on PTK activation induced by H/R. Dose-response experiments revealed that ginsenoside-Rb1 was the most active compound and it completely blocked PTK activation at a wide range of concentrations. Most protopanaxadiol-type ginsenosides and some protopanaxatriol-type saponins also showed significant effects on PTK activation. However, the crude extracts did not protect against H/R-induced PTK activation.