Diterpenoid Lactone Research Articles

The HPLC–MS/MS Method for Determination of Diosbulbin B in the Plasma of Rats Administered with Rhizoma Dioscoreae Bulbiferae Combinations: Application to Comparative Pharmacokinetic Study

Diosbulbin B (DB) is a diterpenoid lactone with a remarkable anticancer effect isolated from Rhizoma Dioscoreae Bulbiferae (RDB). The present study aimed to develop a new and sensitive method for determination of DB in rats after oral administration of single herb RDB decoction and its three combinations with Radix Angelicae Sinensis (RAS). A sensitive and rapid liquid chromatography–tandem mass spectrometry (LC–MS/MS) method with a multiple-reaction monitoring (MRM) mode was employed for quantification of DB in the rat plasma. DB and spinosin (internal standard, IS) were separated on an Xtimate C18 column (4.6 mm × 150 mm, 5 µm) using a gradient mobile phase consisting of water and acetonitrile. The calibration curve was linear over the range of 0.5 to 500 ng/mL. The lower limit of quantification was 0.5 ng/mL. The accuracy and precision of DB in the rat plasma were between −4.2% and 8.1% relative error, and 3.2% to 9.1% relative standard deviation, respectively. The fully validated method was successfully applied to comparative pharmacokinetics (PK) of DB in RDB–RAS combinations. The results showed that components in RAS had a dramatic effect on the PK pattern of DB.

Specificity and inhibitory mechanism of andrographolide and its analogues as antiasthma agents on NF-κB p50.

Andrographolide (1) is a diterpenoid lactone with an α,β-unsaturated lactone group that inhibits NF-κB DNA binding. Andrographolide reacts with the nucleophilic Cys62 of NF-κB p50 through a Michael addition at the Δ(12(13)) exocylic double bond to form a covalent adduct. Using computer docking, site-directed mutagenesis, and mass spectrometry, the noncovalent interactions between andrographolide and additional binding site residues other than Cys62 were found to be essential for the covalent incorporation of andrographolide. Furthermore, the addition reaction of andrographolide on Cys62 was highly dependent on the redox conditions and on the vicinity of nearby, positively charged Arg residues in the conserved RxxRxR motif. The reaction mechanisms of several of the analogues were determined, showing that 14-deoxy-11,12-didehydroandrographolide (8) reacts with NF-κB p50 via a novel mechanism distinct from andrographolide. The noncovalent interaction and redox environment of the binding site should be considered, in addition to the electrophilicity, when designing a covalent drug. Analogues similar in structure appear to use distinct reaction mechanisms and may have very different cytotoxicities, e.g., compound 6.

Andrographolide inhibits intracellular Chlamydia trachomatis multiplication and reduces secretion of proinflammatory mediators produced by human epithelial cells

Chlamydia trachomatis is the most common sexually transmitted bacterial disease worldwide. Untreated C. trachomatis infections may cause inflammation and ultimately damage tissues. Here, we evaluated the ability of Andrographolide (Andro), a natural diterpenoid lactone component of Andrographis paniculata, to inhibit C. trachomatis infection in cultured human cervical epithelial cells. We found that Andro exposure inhibited C. trachomatis growth in a dose- and time-dependent manner. The greatest inhibitory effect was observed when exponentially growing C. trachomatis was exposed to Andro. Electron micrographs demonstrated the accumulation of unusual, structurally deficient chlamydial organisms, correlated with a decrease in levels of OmcB expressed at the late stage of infection. Additionally, Andro significantly reduced the secretion of interleukin6, CXCL8 and interferon-γ-induced protein10 produced by host cells infected with C. trachomatis. These results indicate the efficacy of Andro to perturb C. trachomatis transition from the metabolically active reticulate body to the infectious elementary body and concurrently reduce the production of a proinflammatory mediator by epithelial cells in vitro. Further dissection of Andro's anti-Chlamydia action may provide identification of novel therapeutic targets.

Bioactive constituents from the green alga Caulerpa racemosa

Three diterpenoids, including a pair of epimers, racemobutenolids A and B (1 and 2), and 4′,5′-dehydrodiodictyonema A (3), an α-tocopheroid, α-tocoxylenoxy (8), and an 28-oxostigmastane steroid, (23E)-3β-hydroxy-stigmasta-5,23-dien-28-one (11), together with 12 known compounds, were isolated from the green alga Caulerpa racemosa. The structures of the new compounds were elucidated by detailed analysis of spectroscopic data, and by comparison with data for related known compounds. The epimers (1 and 2) are two unusual diterpenoid lactones bearing a β-methyl-γ-substituted butenolide moiety, and 3 and 8 represent the first naturally occurring natural products with a hematinic acid ester group and 3,5-dimethylphenoxy functionality, respectively. The enzyme inhibitory activities of the isolated compounds were evaluated in vitro against PTP1B and related PTPs (TCPTP, CDC25B, LAR, SHP-1, and SHP-2). Compounds 3, 5, 6, and 9–14 exhibited different levels of PTP1B inhibitory activities with IC50 values ranging from 2.30 to 50.02μM. Of these compounds, 3, 9, and 11 showed the most potent inhibitory activities towards PTP1B with IC50 values of 2.30, 3.85, and 3.80μM, respectively. More importantly, the potent PTP1B inhibitors 3, 9, and 11 also displayed high selectivity over the highly homologous TCPTP and other PTPs. Also, the neuroprotective effects of the isolates against Aβ25-35-induced cell damage in SH-SY5Y cells were investigated. Compounds 10, 11, and 14 exhibited significant neuroprotective effects against Aβ25-35-induced SH-SY5Y cell damage with 11.31–15.98% increases in cell viability at 10μM. In addition, the cytotoxic activities of the isolated compounds were tested against the human cancer cell lines A-549 and HL-60.

Inhibition of MDA-MB-231 breast cancer cell migration and invasion activity by andrographolide via suppression of nuclear factor-κB-dependent matrix metalloproteinase-9 expression.

Breast cancer is one of the most common types of cancer worldwide. The majority of patients with cancer succumb to the disease as a result of distant metastases (for example, in the bones), which cause severe complications. Despite advancements in breast cancer treatment, chemotherapeutic outcomes remain far from satisfactory, prompting a search for effective natural agents with few side-effects. Andrographolide (AP), a natural diterpenoid lactone isolated from Andrographis paniculata, inhibits cancer cell growth. The current study aimed to examine the effect of AP on breast cancer cell proliferation, survival and progression in vitro and also its inhibitory activity on breast cancer bone metastasis in vivo. To achieve this, CCK8, flow cytometry, migration, invasion, western blot, PCR and luciferase reporter assay analyses were performed in vitro as well as establishing intratibial xenograft model of breast cancer bone metastasis in vivo. The results demonstrated that AP inhibits the migration and invasion of the MBA-MD-231 aggressive breast cancer cell line at non-lethal concentrations, in addition to suppressing proliferation and inducing apoptosis at high concentrations in vitro. In vivo, AP significantly inhibited the growth of tumors planted in bone and attenuated cancer-induced osteolysis. Tartrate-resistant acid phosphatase staining revealed osteoclast activation in tumor-bearing mice and AP was observed to attenuate this activation. The anti-tumor activity of AP in vitro and in vivo correlates with the downregulation of the nuclear factor κB signaling pathway and the inhibition of matrix metalloproteinase-9 expression levels. These results indicate that AP may be an effective anti-tumor agent for the treatment of breast cancer bone metastasis.

ASCERTAINING THE MODE OF ACTION OF PHYTOCOMPOUNDS FROM THE MEDICINAL PLANT TINOSPORA CORDIFOLIA USING DOCKING STUDIES

Natural products with medicinal value are progressively ga ining importance in clinical research due to their therapeutic uses with out any side effects when compared to the available drugs . Tinospora cordifolia (Guduchi) is an important herb in folk an d Ayurveda systems of medicine which contains various chemical constituents belonging to different classes such as alkaloids, diterpenoid lactones, glycosides and steroids. The plant i s reported to have antimicrobial, antioxidant , anticancer and recurring resistant with promising role against HIV. So, t he present stud y was designed to find the mode of action for the phytocompounds present in the plant T. co rdifolia against Swine flu, AIDS and Tuberculosis through in silico studies. Docking studies were perform ed by using Autodock 4.1 and results were analysed. From the results it was observed that compound columbin exhibit ed - 7.11kcal/mol binding energy, 4 hydrogen bond interactions with ASP25 of the HIV - 1 protease receptor. Ecdysterone and Giloin exhibited good binding energy and inhibitory constant against both Neurami nidase and HIV - 1 protease receptors.

Synthetic applications of homoiodo allylsilane II. Total syntheses of (−)-andrographolide and (+)-rostratone

The first total synthesis of (−)-andrographolide (1), an ent-Labdane diterpenoid lactone from Asian medicinal herb Andrographis paniculata, was achieved via the biomimetic cyclization of an epoxy homoiodo allylsilane precursor 7. Asymmetric total synthesis of (+)-rostratone (25), an antipodal Labdane diterpenoid, was also accomplished via similar biomimetic cyclization of a readily accessible epoxy homoiodo allylsilane precursor 18.

Cytochrome p450-mediated metabolic activation of diosbulbin B.

Diosbulbin B (DIOB), a furan-containing diterpenoid lactone, is the most abundant component of Dioscorea bulbifera L. (DB), a traditional Chinese medicine herb. Administration of purified DIOB or DB extracts has been reported to cause liver injury in animals. The mechanisms of DIOB-induced hepatotoxicity remain unknown. The major objective of this study was to identify reactive metabolites of DIOB. A DIOB-derived cis-enedial was trapped by N-acetyl lysine (NAL) and glutathione (GSH) or N-acetyl cysteine (NAC) in rat and human liver microsomal incubation systems after exposure to DIOB. Four metabolites (M1-M4) associated with GSH were detected by liquid chromatography coupled to tandem mass spectrometry. Apparently, M1 was derived from both NAL and GSH. M2 and M3 resulted from the reaction of GSH without the involvement of NAL. Two molecules of GSH participated in the formation of M4. M2 and M3 were also detected in bile and urine of rats given DIOB. M5, a DIOB-derived NAC/NAL conjugate, was detected in microsomal incubations with DIOB fortified with NAC and NAL as trapping agents. Biomimetic M1-M5 were prepared by oxidation of DIOB with Oxone for metabolite identification. Microsomal incubation study demonstrated that ketoconazole inhibited the production of the enedial in a concentration-dependent manner, and CYP3A4 was found to be the enzyme responsible for the metabolic activation of DIOB. The metabolism study facilitates the understanding of the role of bioactivation of DIOB in its hepatotoxicity.

Andrographolide inhibits tumor angiogenesis via blocking VEGFA/VEGFR2-MAPKs signaling cascade

Traditional medicinal herb Andrographis paniculata is known to possess anti-tumor activity, and its potential active compound is the diterpenoid lactone andrographolide (ANGL). In this study, we have found that ANGL inhibits tumor growth in nude mice bearing xenografted Hep3B cancer cells, concomitant with a reduction in tumor vessel counts. ANGL inhibits vascular endothelial growth factor A (VEGFA)-induced angiogenic responses in vitro and neoangiogenesis in vivo. We also found that ANGL inhibits VEGFA-induced phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR2) and its downstream targets such as the mitogen-activated protein kinases (MAPKs). ANGL interferes with the binding of VEGFA to VEGFR2, but has no effect on VEGFR2 kinase activity in vitro. Taken together, our results indicate that ANGL possesses anti-angiogenic activity which is mediated by preventing VEGFA-induced phosphorylation and activation of VEGFR2 and MAPKs. The present study indicates that ANGL can block tumor angiogenesis and therefore represents therapeutic potential for cancer treatment.

Andrographolide suppresses IL-6/Stat3 signaling in peripheral blood mononuclear cells from patients with chronic rhinosinusitis with nasal polyps.

The mechanisms underlying the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) remain largely unknown. CRSwNP has garnered considerable public health concern owing to its high incidence and unsatisfactory treatment outcomes. Herbal remedies are promising candidates for the treatment of CRSwNP. We examined the utility of andrographolide, a diterpenoid lactone extracted from the Chinese herb Andrographis paniculata, an anti-inflammatory agent for CRSwNP treatment by evaluating interleukin (IL)-6 and IL-17 production and monitoring T helper 17 (Th17) differentiation of peripheral blood mononuclear cells (PBMCs) isolated from 20 Chinese CRSwNP patients and 11 control subjects. All CRSwNP patients exhibited clinical features of CRSwNP. Andrographolide significantly inhibited IL-6 and IL-17 production, suppressed p-Stat3 expression, and inhibited Th17 differentiation of PBMCs in vitro. These findings suggested that andrographolide has useful anti-inflammatory properties and could be used for the treatment of CRSwNP.

Andrographolide attenuates skeletal muscle dystrophy in mdx mice and increases efficiency of cell therapy by reducing fibrosis

BackgroundDuchenne muscular dystrophy (DMD) is characterized by the absence of the cytoskeletal protein dystrophin, muscle wasting, increased transforming growth factor type beta (TGF-β) signaling, and fibrosis. At the present time, the only clinically validated treatments for DMD are glucocorticoids. These drugs prolong muscle strength and ambulation of patients for a short term only and have severe adverse effects. Andrographolide, a bicyclic diterpenoid lactone, has traditionally been used for the treatment of colds, fever, laryngitis, and other infections with no or minimal side effects. We determined whether andrographolide treatment of mdx mice, an animal model for DMD, affects muscle damage, physiology, fibrosis, and efficiency of cell therapy.Methodsmdx mice were treated with andrographolide for three months and skeletal muscle histology, creatine kinase activity, and permeability of muscle fibers were evaluated. Fibrosis and TGF-β signaling were evaluated by indirect immunofluorescence and Western blot analyses. Muscle strength was determined in isolated skeletal muscles and by a running test. Efficiency of cell therapy was determined by grafting isolated skeletal muscle satellite cells onto the tibialis anterior of mdx mice.Resultsmdx mice treated with andrographolide exhibited less severe muscular dystrophy than untreated dystrophic mice. They performed better in an exercise endurance test and had improved muscle strength in isolated muscles, reduced skeletal muscle impairment, diminished fibrosis and a significant reduction in TGF-β signaling. Moreover, andrographolide treatment of mdx mice improved grafting efficiency upon intramuscular injection of dystrophin-positive satellite cells.ConclusionsThese results suggest that andrographolide could be used to improve quality of life in individuals with DMD.

Andrographolide Sensitizes the Cytotoxicity of Human Colorectal Carcinoma Cells Toward Cisplatin via Enhancing Apoptosis Pathways In Vitro and In Vivo

Andrographolide (Andro), a diterpenoid lactone isolated from a traditional herbal medicine Andrographis paniculata, has been shown to suppress the growth and invasion of human colorectal carcinoma (CRC) Lovo cells, and trigger apoptosis in vitro. The potential of Andro as a chemotherapeutic agent in CRC was evaluated by investigating its cytotoxic effects as a single agent or in coadministration with cisplatin (CDDP). Andro potentiated the cytotoxic effect of CDDP in Lovo cells through apoptosis. The molecular mechanism for these favorable cellular response was further investigated by analyzing the apoptotic profiles, protein levels, and mRNA expression patterns of several key genes after treatments of Andro or/and CDDP. Molecular results indicated that the effect of Andro alone might be mediated via both intrinsic and extrinsic apoptotic pathways in Lovo cells. The addition of Andro to CDDP induced synergistic apoptosis, which could be corroborated to the changes in protein and mRNA levels of Bax and Bcl-2, and the increased Fas/FasL association in these cells, resulting in increased release of cytochrome c, and activation of caspases. Pretreatment of Nok-1 monoclonal antibody, a Fas signaling inhibitor, or Bax inhibitor peptide V5 repressed the Andro-induced cleavage of procaspase and the sensitization to CDDP-induced apoptosis. Finally, the combination therapy of Andro with CDDP was evidenced by its synergistic inhibition on the growth of Lovo cells in xenograft tumor studies. The results indicate that Andro, in combination with chemotherapeutics, is likely to represent a potential therapeutic strategy for CRC.

Andrographolide prevents human breast cancer-induced osteoclastic bone loss via attenuated RANKL signaling

Bone metastasis is a common and serious complication in advanced cancers such as breast cancer, prostate cancer, and multiple myeloma. Agents that prevent bone loss could be used to develop an alternative therapy for bone metastasis. RANKL, a member of the tumor necrosis factor superfamily, has been shown to play a significant role in cancer-associated bone loss. In this study, we examined the efficacy of the natural compound andrographolide (AP), a diterpenoid lactone isolated from the traditional Chinese and Indian medicinal plant Andrographis paniculata, in reducing breast cancer-induced osteolysis. AP prevented human breast cancer-induced bone loss by suppressing RANKL-mediated and human breast cancer cell-induced osteoclast differentiation. Molecular analysis revealed that AP prevented osteoclast function by inhibiting RANKL-induced NF-κB and ERK signaling pathway in lower dose (20 μM), as well as inducing apoptosis at higher dose (40 μM). Thus, AP is a potent inhibitor of breast cancer-induced bone metastasis.

Andrographolide suppresses RANKL‐induced osteoclastogenesis in vitro and prevents inflammatory bone loss in vivo

Osteoclasts play a pivotal role in diseases such as osteoporosis, rheumatoid arthritis and tumour bone metastasis. Thus, searching for natural compounds that may suppress osteoclast formation and/or function is promising for the treatment of osteoclast-related diseases. Here, we examined changes in osteoclastogenesis and LPS-induced osteolysis in response to andrographolide (AP), a diterpenoid lactone isolated from the traditional Chinese and Indian medicinal plant Andrographis paniculata. Effects of AP on osteoclast differentiation and bone resorption were measured in vitro. Western blots and RT-PCR techniques were used to examine the underlying molecular mechanisms. The bone protective activity of AP in vivo was assessed in a mouse model of osteolysis. AP concentration-dependently suppressed RANKL-mediated osteoclast differentiation and bone resorption in vitro and reduced the expression of osteoclast-specific markers, including tartrate-resistant acid phosphatase, calcitonin receptors and cathepsin K. Further molecular analysis revealed that AP impaired RANKL-induced NF-κB signalling by inhibiting the phosphorylation of TGF-β-activated kinase 1, suppressing the phosphorylation and degradation of IκBα, and subsequently preventing the nuclear translocation of the NF-κB p65 subunit. AP also inhibited the ERK/MAPK signalling pathway without affecting p38 or JNK signalling. AP suppressed RANKL-induced osteoclastogenesis through attenuating NF-κB and ERK/MAPK signalling pathways in vitro, thus preventing bone loss in vivo. These data indicated that AP is a promising natural compound for the treatment of osteoclast-related bone diseases.

Andrographolide induces apoptosis of C6 glioma cells via the ERK-p53-caspase 7-PARP pathway.

Background. Glioma is the most malignant tumor of the central nervous system. Efforts on the development of new chemotherapy are mandatory. Andrographolide (AND), a diterpenoid lactone isolated from the Andrographis paniculata, has been shown to have antitumor activities in several types of cancer cells. Whether AND can exert its antitumor activity in glioblastoma cells remains unknown. This study examined the anticancer effects of AND, both in vitro and in vivo. Methods. Cell apoptosis was assayed by flow cytometry and nuclear staining. The signaling pathway for AND was determined by western blotting. The effects of AND on tumor growth was evaluated in a mouse model. Results and Conclusion. In vitro, with application of specific inhibitors and siRNA, AND-induced apoptosis was proven through ROS-ERK-P53-caspase 7-PARP signaling pathway. In vivo, AND significantly retarded tumor growth and caused regression of well-formed tumors in vivo. Furthermore, AND did not induce apoptosis or activate ERK and p53 in primary cultured astrocyte cells, and it may serve as a potential therapeutic candidate for the treatment of glioma.

Andrographolide exerts anti‐hepatitis C virus activity by up‐regulating haeme oxygenase‐1 via the p38 MAPK/Nrf2 pathway in human hepatoma cells

This study aimed to evaluate the anti-hepatitis C virus (HCV) activity of andrographolide, a diterpenoid lactone extracted from Andrographis paniculata, and to identify the signalling pathway involved in its antiviral action. Using HCV replicon and HCVcc infectious systems, we identified anti-HCV activity of andrographolide by measuring protein and RNA levels. A reporter activity assay was used to determine transcriptional regulation of anti-HCV agents. A specific inhibitor and short hairpin RNAs were used to investigate the mechanism responsible for the effect of andrographolide on HCV replication. In HCV replicon and HCVcc infectious systems, andrographolide time- and dose-dependently suppressed HCV replication. When combined with IFN-α, an inhibitor targeting HCV NS3/4A protease (telaprevir), or NS5B polymerase (PSI-7977), andrographolide exhibited a significant synergistic effect. Andrographolide up-regulated the expression of haeme oxygenase-1 (HO-1), leading to increased amounts of its metabolite biliverdin, which was found to suppress HCV replication by promoting the antiviral IFN responses and inhibiting NS3/4A protease activity. Significantly, these antiviral effects were attenuated by an HO-1-specific inhibitor or HO-1 gene knockdown, indicating that HO-1 contributed to the anti-HCV activity of andrographolide. Andrographolide activated p38 MAPK phosphorylation, which stimulated nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated HO-1 expression, and this was found to be associated with its anti-HCV activity. Our results demonstrate that andrographolide has the potential to control HCV replication and suggest that targeting the Nrf2-HO-1 signalling pathway might be a promising strategy for drug development.

Qualitative and Quantitative Analysis of Andrographis paniculata by Rapid Resolution Liquid Chromatography/Time-of-Flight Mass Spectrometry

A rapid resolution liquid chromatography/time-of-flight tandem mass spectrometry (RRLC-TOF/MS) method was developed for qualitative and quantitative analysis of the major chemical constituents in Andrographis paniculata. Fifteen compounds, including flavonoids and diterpenoid lactones, were unambiguously or tentatively identified in 10 min by comparing their retention times and accurate masses with standards or literature data. The characteristic fragmentation patterns of flavonoids and diterpenoid lactones were summarized, and the structures of the unknown compounds were predicted. Andrographolide, dehydroandrographolide and neoandrographolide were further quantified as marker substances. It was found that the calibration curves for all analytes showed good linearity (R2 > 0.9995) within the test ranges. The overall limits of detection (LODs) and limits of quantification (LOQs) were 0.02 μg/mL to 0.06 μg/mL and 0.06 μg/mL to 0.2 μg/mL, respectively. The relative standard deviations (RSDs) for intra- and inter-day precisions were below 3.3% and 4.2%, respectively. The mean recovery rates ranged from 96.7% to 104.5% with the relative standard deviations (RSDs) less than 2.72%. It is concluded that RRLC-TOF/MS is powerful and practical in qualitative and quantitative analysis of complex plant samples due to time savings, sensitivity, precision, accuracy and lowering solvent consumption.

Andrographolide derivatives inhibit guanine nucleotide exchange and abrogate oncogenic Ras function

Aberrant signaling by oncogenic mutant rat sarcoma (Ras) proteins occurs in ∼15% of all human tumors, yet direct inhibition of Ras by small molecules has remained elusive. Recently, several small-molecule ligands have been discovered that directly bind Ras and inhibit its function by interfering with exchange factor binding. However, it is unclear whether, or how, these ligands could lead to drugs that act against constitutively active oncogenic mutant Ras. Using a dynamics-based pocket identification scheme, ensemble docking, and innovative cell-based assays, here we show that andrographolide (AGP)--a bicyclic diterpenoid lactone isolated from Andrographis paniculata--and its benzylidene derivatives bind to transient pockets on Kirsten-Ras (K-Ras) and inhibit GDP-GTP exchange. As expected for inhibitors of exchange factor binding, AGP derivatives reduced GTP loading of wild-type K-Ras in response to acute EGF stimulation with a concomitant reduction in MAPK activation. Remarkably, however, prolonged treatment with AGP derivatives also reduced GTP loading of, and signal transmission by, oncogenic mutant K-RasG12V. In sum, the combined analysis of our computational and cell biology results show that AGP derivatives directly bind Ras, block GDP-GTP exchange, and inhibit both wild-type and oncogenic K-Ras signaling. Importantly, our findings not only show that nucleotide exchange factors are required for oncogenic Ras signaling but also demonstrate that inhibiting nucleotide exchange is a valid approach to abrogating the function of oncogenic mutant Ras.

12-Amino-andrographolide analogues: synthesis and cytotoxic activity

Andrographolide, a diterpenoid lactone of the plant Andrographis paniculata, has been shown to be cytotoxic against various cancer cells in vitro. In the present study, a series of β-amino-γ-butyrolactone analogues has been synthesized from naturally occurring andrographolide via one pot tandem aza-conjugate addition-elimination reaction. By using economic procedure without any base or catalyst at room temperature, the products obtained were in fair to excellent yields with high stereoselectivity. The cytotoxicity of all new amino analogues were evaluated against six cancer cell lines and revealed their potential for being developed as promising anti-cancer agents.

Preventive effects of andrographolide on the development of diabetes in autoimmune diabetic NOD mice by inducing immune tolerance

Andrographolide, an active component in traditional anti-diabetic herbal plants, is a diterpenoid lactone isolated from Andrographis paniculata because of its potent anti-inflammatory and hypoglycemic effects. However, the effect of andrographolide on the development of diabetes in autoimmune non-obese diabetic (NOD) mice remains unknown. This study aimed to investigate the protective effects of andrographolide on the development of autoimmune diabetes and clarify the underlying mechanism. NOD mice were randomly divided into four groups and administered with water and andrographolide at 50, 100, and 150mg/kg body weight for four weeks. ICR mice were also selected as the control group. Oral glucose tolerance and histopathological insulitis were examined. Th1/Th2/Th17 cytokine secretion was determined by ELISA. The transcriptional profiles of T-bet, GATA3, and RORγt in the pancreatic lymphatic node samples derived from the NOD mice were detected by RT-PCR. After four weeks of oral supplementation, andrographolide significantly inhibited insulitis, delayed the onset, and suppressed the development of diabetes in 30-week-old NOD mice in a dose dependent manner. This protective status was correlated with a substantially decreased production of interferon (IFN)-γ and interleukin (IL)-2, increased IL-10 and transforming growth factor (TGF)-β, and a reduced IL-17. Andrographolide also increased GATA3 mRNA expression but decreased T-bet and RORγt mRNA expressions. Our results suggested that andrographolide prevented type 1 diabetes by maintaining Th1/Th2/Th17 homeostasis.