Platycodin D2 (1), a less hemolytic saponin from the root of Platycodon grandiflorum than platycodin D (2), was evaluated for the potential to enhance specific cellular and humoral immune responses to hepatitis B surface antigen (HBsAg) in mice. It significantly increased the concanavalin A (Con A)-, lipopolysaccharide (LPS)-, and HBsAg-induced splenocyte proliferation in HBsAg-immunized mice (P<0.05, P<0.01, and P<0.001, resp.). HBsAg-specific IgG, IgG1, IgG2a, and IgG2b antibody titers in the serum were also markedly enhanced by 1 compared to the HBsAg control group (P<0.01 or P<0.001). Moreover, 1 significantly promoted the production of Th1 (IL-2 and IFN-γ) and Th2 (IL-4 and IL-10) cytokines from splenocytes in the HBsAg-immunized mice (P<0.001). The adjuvant potential of 1 on splenocyte proliferation, serum HBsAg-specific IgG2a and IgG2b antibody response, as well as Th1-cytokine secretion from splenocytes in the HBsAg-immunized mice was higher than that of Alum. The results suggest that 1 could improve both cellular and humoral immune responses to HBsAg in mice. Hence, 1 might be a promising adjuvant for hepatitis B vaccine with dual Th1- and Th2-potentiating activity.
The development of an effective influenza vaccine is urgently important for controlling outbreaks of the highly pathogenic avian influenza virus (HPAIV) and reducing the impact of pandemics. The use of an adjuvant in such a vaccine can significantly contribute to improve the immunogenicity. To explore a novel and safe adjuvant for improving the potency of influenza vaccines, platycodin D (1), a saponin from the root of Platycodon grandiflorum, was evaluated for the adjuvant potentials on the specific cellular and humoral immune responses to Newcastle disease virus-based recombinant avian influenza vaccine (rL-H5) in mice. Compound 1 significantly promoted the concanavalin A (Con A)-, the lipopolysaccharide (LPS)-, and the antigen-induced splenocyte proliferation and enhanced the serum antigen-specific IgG, IgG1, IgG2a, and IgG2b antibody titers (P<0.05, P<0.01, or P<0.001) in mice immunized with rL-H5. The mRNA expressions of Th1/Th2 cytokines (IFN-γ and IL-10) and transcription factors (T-bet and GATA-3) in splenocytes were also markedly up-regulated by 1, compared with the control group immunized with rL-H5 alone (P<0.01 or P<0.001). In addition, 1 remarkably increased the killing activities of natural killer (NK) cells from splenocytes in the immunized mice (P<0.05), which may have important implications for the vaccination against the avian influenza virus. We concluded that 1 could improve the immunogenicity of the rL-H5 vaccine by enhancing both humoral and cellular immune responses in mice, and that 1 is a promising adjuvant for influenza vaccines.
3β,6β-Dihydroxyolean-12-en-27-oic acid (1) is a pentacyclic triterpenoid isolated from the rhizomes of Astilbe chinensis. To evaluate the in vivo antitumor potential and to elucidate its immunological mechanisms, effect of 1 on the growth of mouse-transplantable tumors, and the immune response in naive and tumor-bearing mice were investigated. The mice inoculated with mouse tumor cell lines were orally treated with 1 at the doses of 40, 60, and 80 mg/kg for 10 days. The effects of 1 on the growth of mouse-transplantable S180 sarcoma and H22 hepatoma, splenocyte proliferation, cytotoxic T lymphocyte (CTL) activity, natural killer (NK) cell activity, and production of interleukin-2 (IL-2) from splenocytes in S180-bearing mice were measured. Furthermore, the effect of 1 on 2,4-dinitrofluorobenzene (DNFB)-induced delayed-type hypersensitivity (DTH) reactions and the sheep red blood cell (SRBC)-induced antibody response in naive mice were also studied. Compound 1 could not only significantly inhibit the growth of mouse transplantable S180 sarcoma and H22 hepatoma, increase splenocytes proliferation, CTL and NK cell activity, and the level of IL-2 secreted by splenocytes in tumor-bearing mice, but also remarkably promote the DTH reaction and enhance anti-SRBC antibody titers in naive mice. These results suggested that 1 could improve both cellular and humoral immune response, and could act as antitumor agent with immunomodulatory activity.
A new ursane-based compound, astilbotriterpenic acid (1), was isolated from the rhizomes of Astilbe chinensis. Its structure was determined on the basis of chemical evidence and extensive spectroscopic methods, including 1D- and 2D-NMR. The pentacyclic triterpenoid 1 was assayed for its in vitro cytotoxicity against Bcap37, HeLa, HepG2, HO-8910, K562, PAA, SGC7901, and P388 cancer cells, as well as for its apoptosis-inducing activity in HeLa cells. Compound 1 was found to strongly inhibit tumor-cell growth through induction of apoptosis and may, thus, be further evaluated as a novel chemotherapeutic agent.
The immunosuppressive activity of the ethanol extract of Sedum sarmentosum (EESS) and its fractions was studied with respect to specific antibody and cellular response to ovalbumin (OVA) in mice. ICR Mice were immunized subcutaneously with OVA on days 0 and 14. Beginning on the day of immunization, the mice were administered intraperitoneally (ip) with EESS and it fractions at a single dose of 0.25, 0.5, and 1.0 mg, and cyclosporin A at a single dose of 0.1 mg at intervals of 7 days. On day 28, splenocyte proliferation and specific antibody level in serum were measured. EESS significantly suppressed concanavalin A (Con A)-, lipopolysaccharide (LPS)-, and OVA-induced splenocyte proliferation in the immunized mice in a dose-dependent manner. The OVA-specific serum IgG, IgG1, and IgG2b levels in the immunized mice were also markedly reduced by EESS. Among four fractions of EESS, the BuOH fraction consisting mainly of flavonoid glycosides showed the highest suppressive activity. The results suggest that EESS could suppress the cellular and humoral immune response in mice, and deserve further research to be developed as immunosuppressant.
Ginsenoside Rh4 (1), a saponin isolated from the roots of Panax notoginseng (Burk.) F. H. Chen, was evaluated for its haemolytic activity and adjuvant potential on specific antibody and cellular response to ovalbumin (OVA) in mice. Compound 1 showed a slight haemolytic effect, its concentration inducing 50% of the maximum haemolysis (HD50 value) being 407±12 μg/ml using a 0.5% suspension of red blood cells. Compound 1 significantly increased the concanavalin A (Con A)-, lipopolysaccharide (LPS)-, and OVA-induced splenocyte proliferation in OVA-immunized mice especially at a dose of 25 μg (P<0.05, P<0.01, or P<0.001). The OVA-specific serum IgG, IgG1, and IgG2b antibody levels were also significantly enhanced by 1 at a dose of 25 μg compared to the OVA control group (P<0.05 or P<0.01). Moreover, the enhancing effect of 1 on the OVA-specific IgG2b antibody responses to OVA in mice was more significant than that of Alum (Al(OH)3 gel; P<0.01). These results suggest that 1 could be safely used as adjuvant with low or non-haemolytic effect.
The saponin ginsenoside Rd (1), isolated from Panax notoginseng, is used for the treatment of cardiovascular diseases, inflammation, different body pains, trauma, and internal and external bleeding due to injury. In this study, we report that 1 inhibits the cell growth of human cervical cancer (HeLa) cells in a concentration- and time-dependent manner, with an IC50 value of 150.5±0.8 μg/ml after 48 h of incubation. The drug-treated cells displayed features of apoptosis, including typical morphological characteristics and formation of DNA ladders, as evident from agarose-gel electrophoresis. Flow-cytometric analysis showed that the cell-cycle distribution of HeLa cells exposed to 1 is characterized by a decrease of the G0/G1-phase and an increase of the S-phase cells, respectively, in a dose-dependent manner. The apoptotic rate of HeLa cells treated for 48 h with 210 μg/ml of 1 was 35.8%. Further, 1 was found to increase the expression of Bax and to decrease the expression of Bcl-2 proteins, respectively, and to lower the mitochondrial transmembrane potential of HeLa cells. The caspase-3 inhibitor DEVD-CHO (at 2 μM) increased the viability of HeLa cells treated with 1. Taken together, our study suggests that ginsenoside Rd (1) significantly inhibits HeLa cell proliferation, and induces cell apoptosis through down-regulating Bcl-2 expression, up-regulating Bax expression, lowering the mitochondrial transmembrane potential, and activating the caspase-3 pathway. Thus, 1 could serve as a lead to develop novel chemotherapeutic or chemopreventive agents against human cervical cancer.
3β-Hydroxyurs-12-en-27-oic acid (1), a pentacyclic triterpenoid isolated from the rhizomes of Astilbe chinensis, was structurally very similar to ursolic acid, with the only difference being the interchange of the COOH and Me group at C(14) and C(17). Ursane-type triterpene with a COOH group at C(14) is present in a limited number of natural resources. Compound 1 was found to exhibit more distinctive cytotoxicity toward human cervical squamous carcinoma (HeLa) cells than ursolic acid, suggesting that the position of the COOH group significantly affects the cytotoxicity of ursane-type pentacyclic triterpenes with a COOH group. To elucidate the underlying biological mechanism responsible for the cytotoxicity of 1, we investigated its growth-inhibitory and apoptosis-inducing effect on HeLa cells. Compound 1 induced a marked concentration- and time-dependent inhibition of cell proliferation with an IC50 value of 6.80±0.88 μg/ml following 48 h incubation. The drug-treated HeLa cells displayed typical morphological apoptotic characteristics and formation of DNA ladders in agarose-gel electrophoresis. Flow cytometric analysis showed that the cell cycle was arrested in G0/G1 phase by 1, and the apoptotic rate of HeLa cells treated for 48 h with 20 μg/ml of 1 was 21.08±2.14%. Also, 1 increased and decreased the expression of Bax and Bcl-2 proteins, respectively, and lowered the mitochondrial transmembrane potential (Δψm). The peptidic capase-3 inhibitor DEVD-CHO (NH2-Asp-Glu-Val-Asp-CHO, at 2 μM) could increase the viability of HeLa cells previously treated with 1. These results indicate that 1 induces efficient cell apoptosis through down-regulating Bcl-2 expression, up-regulating Bax expression, lowering Δψm, and by activating the caspase-3 pathway.
The in vitro and in vivo immunosuppressive activity of the ethanol extract of Siegesbeckia orientalis (EESO) was studied on the immune responses in mice. EESO significantly suppressed concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated splenocyte proliferation in vitro in a concentration-dependent manner. ICR Mice were immunized subcutaneously with ovalbumin (OVA) on days 0 and 14. Beginning on the day of immunization, the mice were administered intraperitoneally with EESO at a single dose of 0.25, 0.5, and 1.0 mg at intervals of 7 days. On day 28, OVA-specific antibodies in serum, and mitogen- and OVA-induced splenocyte proliferation were measured. EESO significantly suppressed Con A-, LPS- and OVA-induced splenocyte proliferation in the OVA-immunized mice in a dose-dependent manner. The OVA-specific serum IgG, IgG1, and IgG2b levels in the OVA-immunized mice were also significantly reduced by EESO. Moreover, reducing effect on the IgG1 antibody of EESO at the dose of 1.0 mg was more significant than that of cyclosporin A (CsA; positive drug). The results suggest that EESO could suppress the cellular and humoral response to ovalbumin in mice, and deserve further investigations to be developed as immunosuppressant.
The further purification of the total saponins from the roots of Panax notoginseng (Burk.) F. H. Chen by ordinary and reversed-phase silica-gel, as well as Sephadex LH-20 chromatography afforded two adjuvant active dammarane-type saponins, ginsenoside Re (1) and notoginsenoside R1 (2). These two saponins were evaluated for haemolytic activities and adjuvant potentials on the cellular and humoral immune responses of ICR mice against ovalbumin (OVA). The concentrations inducing 50% of the maximum haemolysis (HD50), using 0.5% red blood cell suspensions, were 469.6±16.9 and 420.4±22.9 μg/ml for 1 and 2, respectively. Compounds 1 and 2 significantly increased the concanavalin A (Con A)-, lipopolysaccharide (LPS)-, and OVA-induced splenocyte proliferation in the OVA-immunized mice (P<0.05, P<0.01, or P<0.001). The OVA-specific IgG, IgG1, and IgG2b antibody titres in serum were also significantly enhanced by 1 and 2 compared with OVA control group (P<0.05, P<0.01, or P<0.001). The results indicate that 1 and 2 showed a slight haemolytic activity and significant adjuvant effect on specific antibody and cellular immune response against OVA in mice, and that the type of the terminal sugar of the sugar chain at C(6) of protopanaxatriol 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 structurefunction relationship might be useful for developing semisynthetic dammarane-type saponin derivatives with immunological adjuvant activity.
The immunosuppressive activity of the ethanol extract of Semen Persicae (EESP) was studied with respect to specific antibody and cellular response to ovalbumin (OVA) in mice. The effects of EESP on mice splenocyte proliferation in vitro were measured. EESP significantly suppressed concanavalin A (ConA)- and lipopolysaccharide (LPS)-stimulated splenocyte proliferation in vitro in a concentration-dependent manner. Furthermore, the effects of EESP at three dose levels on the humoral and cellular immune responses in the OVA-immunized mice were examined. ICR Mice were immunized subcutaneously with OVA on day 0 and 14. Starting on the day of immunization, the mice were administered intraperitoneally with EESP at a single dose of 0.25, 0.5, and 1.0 mg, and cyclosporin A (CsA, positive drug) at a single dose of 0.1 mg at intervals of 7 days. On day 28, mitogen- and OVA-induced splenocyte proliferation and OVA-specific antibody level in serum were measured. EESP significantly decreased ConA-, LPS-, and OVA-induced splenocyte proliferation in the OVA-immunized mice at the dose of 1.0 mg. Meanwhile, the OVA-specific serum IgG, IgG1, and IgG2b antibody levels in the OVA-immunized mice were markedly reduced by EESP in a dose-dependent manner. The results suggest that EESP could suppress the cellular and humoral immune response in mice, and deserve further research to be developed as immunosuppressant.
Notoginsenoside K (1), a saponin isolated from the roots of Panax notoginseng (Burk.) F. H. Chen, was evaluated for its haemolytic activity and adjuvant potential on specific antibody and cellular response to ovalbumin (OVA) in mice. Compound 1 showed a slight haemolytic effect, its concentration inducing 50% of the maximum haemolysis (HD50 value) being 318±13 μg/ml, on a 0.5% suspension of red blood cells. Compound 1 significantly increased the concanavalin A (Con A)-, lipopolysaccharide (LPS)-, and OVA-induced splenocyte proliferation in OVA-immunized mice (P<0.05, P<0.01, or P<0.001). The OVA-specific serum IgG, IgG1, and IgG2b antibody levels were also significantly enhanced by 1, especially at a dose of 25 μg compared to an OVA control group (P<0.001). Moreover, the enhancing effect of 1 on the OVA-specific IgG2b antibody responses to OVA in mice was more significant than that of Alum (AlOH gel; P<0.01). These results suggest that 1 exhibits a slight haemolytic activity and a significant adjuvant effect on specific antibody and cellular response against OVA in mice.
3β-Hydroxyolean-12-en-27-oic acid (1), a biologically active, pentacyclic triterpenoid isolated from the rhizomes of Astilbe chinensis, was found to be considerably more cytotoxic toward human colorectal carcinoma (COLO-205) and human cervical squamous carcinoma (HeLa) cells than its congener oleanolic acid (4). This suggests that the position of the COOH group significantly affects the cytotoxicity of oleanane-type pentacyclic triterpene carboxylic acids. To elucidate the underlying biological mechanism responsible for the cytotoxicity of 1, we investigated its growth-inhibitory effect on COLO-205 cells. Compound 1 induced a marked concentration- and time-dependent inhibition of cell proliferation, with the typical morphological characteristics of apoptosis, and under formation of DNA ladders in agarose-gel electrophoresis. Flow-cytometric analysis showed that the cell cycle of COLO-205 cells exposed to 1 was arrested in the G0/G1 phase. Also, 1 increased and decreased the expression of Bax and Bcl-2 proteins, respectively, and lowered the mitochondrial transmembrane potential (Δψm). The peptidic capase-3 inhibitor NH2-Asp-Glu-Val-Asp-CHO (at 1 μM) could increase the viability of COLO-205 cells previously treated with 1. These results indicate that 1 induces efficient cell apoptosis through down-regulating Bcl-2 expression, up-regulating Bax expression, lowering Δψm, and by activating the caspase-3 pathway.
The total saponin extract from the dried roots of Panax notoginseng (Burk.) F. H. Chen possesses immunological-adjuvant activities. Guided by in vivo immunological tests, further study on this fraction afforded three active dammarane-type saponins. Their structures were determined on the basis of chemical evidence and extensive spectroscopic methods, including 1D- and 2D-NMR. The novel compound (20S)-protopanaxatriol 20-O-β-D-glucopyranosyl-(16)-β-D-glucopyranoside (1), and the two known compounds ginsenoside Rh4 (2) and notoginsenoside K (3) exhibited immunological-adjuvant activities on the humoral immune responses of ICR mice against ovalbumin (OVA).
The volatile oil from the roots of Patrinia scabra Bunge was isolated by steam distillation, and separated into four major fractions (Fr. A–D) by means of column chromatography. A total of 39 compounds (1–39) were identified by GC/MS analysis, and evaluated for their in vitro cytotoxic activities against human ovarian carcinoma cells (HO-8910) and human hepatoma cells (Bel-7402) (Table 1). Fr. A showed the strongest inhibitory effect on HO-8910 (IC50=21 μg/ml) and Bel-7402 cells (16 μg/ml), whereas Fr. B was the least active (>100 μg/ml). By comparison of the constituents of the four fractions, we assume that the cytotoxicity of the volatile oil of P. scabra is mainly due to the lignans and azulenes, rather than to caryophyllene oxide I (18). Our results suggest that the volatile oil of P. scabra possesses potent and tumor-specific cytotoxicity, and could serve as a possible candidate for future cancer chemotherapy.