Attenuation of Innate Immunity by Andrographolide Derivatives Through NF-κB Signaling Pathway

Tissue-Level Effect of Andrographis and Ashwagandha Metabolites on Metabolic and Inflammatory Gene Expression in Skeletal Muscle and Adipose Tissue: An Ex Vivo/In Vitro Investigation

Adipose tissue and skeletal muscle dysfunction play a central role in cardiometabolic morbidity. Ashwagandha and Andrographis are purported to have anti-inflammatory and antioxidant activity, but this is based on exposure of cells to the parent compounds ignoring phytochemical absorption and metabolism. We explored the anti-inflammatory/antioxidant effects of ashwagandha and Andrographis in ex vivo human models of skeletal muscle and adipose tissue. Healthy participants supplemented with 2000 mg/day Andrographis (n = 10) or 1100 mg/day ashwagandha (n = 10) for 28 days. Sera collected pre (D0) and post (D28) supplementation were pooled by timepoint and added to adipose explant (AT) and primary human myotube (SKMC) culture media (15% v/v) for treatment. A Taqman panel of 56 genes was used to quantify these. In AT, treatment with ashwagandha sera decreased the expression of genes involved in antioxidant defence and inflammatory response (CCL5, CD36, IL6, IL10, ADIPOQ, NFEL2, UCP2, GPX3, GPX4; geometric 95% CI for fold change > 1) and altered the expression of genes involved in fatty acid metabolism. In SKMC, ashwagandha sera altered FOXO1 and SREBF1 expression. Andrographis sera decreased IL18 and SERPINEA3 expression in AT. This physiologically relevant in vitro screening characterises the effects of ashwagandha in AT to guide future clinical trials.

Toll-like receptors in inflammatory bowel disease: A review of the role of phytochemicals

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammation within the gastrointestinal tract with a remarkable impact on patients' quality of life. Toll-like receptors (TLR), as a key contributor of immune system in inflammation, has a critical role in the pathogenesis of IBD and thus, can be a suitable target of therapeutic agents. Medicinal plants have long been considered as a source of bioactive agents for different diseases, including IBD.

PURPOSE

This review discusses current state of the art on the role of plant-derived compounds for the management of IBD with a focus on TLRs.

METHODS

Electronic database including PubMed, Web of Science, and Scopus were searched up to January 2023 and all studies in which anticolitis effects of a phytochemical was assessed via modulation of TLRs were considered.

RESULTS

Different categories of phytochemicals, including flavonoids, lignans, alkaloids, terpenes, saccharides, and saponins have demonstrated modulatory effects on TLR in different animal and cell models of bowel inflammation. Flavonoids were the most studied phytochemicals amongst others. Also, TLR4 was the most important type of TLRs which were modulated by phytochemicals. Other mechanisms such as inhibition of pro-inflammatory cytokines, nuclear factor-κB pathway, nitric oxide synthesis pathway, cyclooxygenase-2, lipid peroxidation, as well as induction of endogenous antioxidant defense mechanisms were also reported for phytochemicals in various IBD models.

CONCLUSION

Taken together, a growing body of pre-clinical evidence support the efficacy of herbal compounds for the treatment of IBD via modulation of TLRs. Future clinical studies are recommended to assess the safety and efficacy of these compounds in human.

Albicanol antagonizes PFF-induced mitochondrial damage and reduces inflammatory factors by regulating innate immunity

As an environmental pollutant, profenofos (PFF) can seriously endanger human health through the food chain. Albicanol is a sesquiterpene compound with antioxidant, anti-inflammatory, and anti-aging properties. Previous studies have shown that Albicanol can antagonize apoptosis and genotoxicity caused by PFF exposure. However, the toxicity mechanism of PFF regulating hepatocyte immune function, apoptosis, and programmed necrosis and the role of Albicanol in this process have not been reported yet. In this study, grass carp hepatocytes (L8824) were treated with PFF (200 μM) or combined with Albicanol (5 ×10^-5 μg mL^-1) for 24 h to establish an experimental model. The results of JC-1 probe staining and Fluo-3 AM probe staining showed increased free calcium ions and decreased mitochondrial membrane potential in L8824 cells after PFF exposure, suggesting that PFF exposure may lead to mitochondrial damage. Real-time quantitative PCR and Western blot results showed that PFF exposure could increase the transcription of innate immunity-related factors (C3, Pardaxin 1, Hepcidin, INF-γ, IL-8, and IL-1β) in L8824 cells. PFF up-regulated the TNF/NF-κB signaling pathway and the expression of caspase-3, caspase-9, Bax, MLKL, RIPK1, and RIPK3 and down-regulated the expression of Caspase-8 and Bcl-2. Albicanol can antagonize the above-mentioned effects caused by PFF exposure. In conclusion, Albicanol antagonized the mitochondrial damage, apoptosis, and necroptosis of grass carp hepatocytes caused by PFF exposure by inhibiting the TNF/NF-κB pathway in innate immunity.

Fighting cytokine storm and immunomodulatory deficiency: By using natural products therapy up to now

A novel coronavirus strain (COVID-19) caused severe illness and mortality worldwide from 31 December 2019 to 21 March 2023. As of this writing, 761,071,826 million cases have been diagnosed worldwide, with 6,879,677 million deaths accorded by WHO organization and has spread to 228 countries. The number of deaths is closely connected to the growth of innate immune cells in the lungs, mainly macrophages, which generate inflammatory cytokines (especially IL-6 and IL-1β) that induce "cytokine storm syndrome" (CSS), multi-organ failure, and death. We focus on promising natural products and their biologically active chemical constituents as potential phytopharmaceuticals that target virus-induced pro-inflammatory cytokines. Successful therapy for this condition is currently rare, and the introduction of an effective vaccine might take months. Blocking viral entrance and replication and regulating humoral and cellular immunity in the uninfected population are the most often employed treatment approaches for viral infections. Unfortunately, no presently FDA-approved medicine can prevent or reduce SARS-CoV-2 access and reproduction. Until now, the most important element in disease severity has been the host's immune response activation or suppression. Several medicines have been adapted for COVID-19 patients, including arbidol, favipiravir, ribavirin, lopinavir, ritonavir, hydroxychloroquine, chloroquine, dexamethasone, and anti-inflammatory pharmaceutical drugs, such as tocilizumab, glucocorticoids, anakinra (IL-1β cytokine inhibition), and siltuximab (IL-6 cytokine inhibition). However, these synthetic medications and therapies have several side effects, including heart failure, permanent retinal damage in the case of hydroxyl-chloroquine, and liver destruction in the case of remdesivir. This review summarizes four strategies for fighting cytokine storms and immunomodulatory deficiency induced by COVID-19 using natural product therapy as a potential therapeutic measure to control cytokine storms.

Andrographolide protects against doxorubicin-and arsenic trioxide-induced toxicity in cardiomyocytes

BACKGROUND

Andrographolide (AG) is a lactone diterpene with valuable biological activities. This in vitro study evaluated whether AG can protect cardiomyocytes under toxicities triggered with anti-cancer chemotherapeutic agents, doxorubicin (DOX) and arsenic trioxide (ATO).

METHODS AND RESULTS

H9C2 cells were pretreated with AG (0.5-10 µM) for 24 h and then exposed to DOX (1 μM) or ATO (35 μM) for another 24 h period. For determination of cell viability or cytotoxicity, MTT and lactate dehydrogenase (LDH) assay were used. Total oxidant and antioxidant capacities were estimated by determining hydroperoxides and ferric reducing antioxidant power (FRAP) levels. Real time-polymerase chain reaction was also used for quantitative evaluation of TLR4 gene expression. AG inhibited cardiomyocytes proliferation at the concentrations of more than 20 μM. However, it considerably enhanced cell viability and decreased cytotoxicity of DOX and ATO at the concentration range of 2.5-10 μM in MTT and LDH assays. AG significantly declined hydroperoxides concentration in ATO-treated cardiomyocytes and raised FRAP value in DOX- and ATO-treated cells. Furthermore, AG notably lessened TLR4 expression in H9C2 cells after exposure to DOX- and ATO.

CONCLUSION

In conclusion, these data presented that AG was able to reverse DOX- and ATO-induced cardiotoxicity in vitro. The cardiomyocyte protective activities of AG may be due to the decrease in TLR4 expression and total oxidant capacity and increase in total antioxidant capacity.

Andrographolide, a natural anti-inflammatory agent: An Update

Botanicals have attracted much attention in the field of anti-inflammatory due to their good pharmacological activity and efficacy. Andrographis paniculata is a natural plant ingredient that is widely used around the world. Andrographolide is the main active ingredient derived from Andrographis paniculata, which has a good effect on the treatment of inflammatory diseases. This article reviews the application, anti-inflammatory mechanism and molecular targets of andrographolide in different inflammatory diseases, including respiratory, digestive, immune, nervous, cardiovascular, skeletal, and tumor system diseases. And describe its toxicity and explain its safety. Studies have shown that andrographolide can be used to treat inflammatory lesions of various systemic diseases. In particular, it acts on many inflammation-related signalling pathways. The future direction of andrographolide research is also introduced, as is the recent research that indicates its potential clinical application as an anti-inflammatory agent.

The NLRP3 Inflammasome Pathway: A Review of Mechanisms and Inhibitors for the Treatment of Inflammatory Diseases

The NLRP3 inflammasome is a multiprotein complex that plays a pivotal role in regulating the innate immune system and inflammatory signaling. Upon activation by PAMPs and DAMPs, NLRP3 oligomerizes and activates caspase-1 which initiates the processing and release of pro-inflammatory cytokines IL-1β and IL-18. NLRP3 is the most extensively studied inflammasome to date due to its array of activators and aberrant activation in several inflammatory diseases. Studies using small molecules and biologics targeting the NLRP3 inflammasome pathway have shown positive outcomes in treating various disease pathologies by blocking chronic inflammation. In this review, we discuss the recent advances in understanding the NLRP3 mechanism, its role in disease pathology, and provide a broad review of therapeutics discovered to target the NLRP3 pathway and their challenges.

Andrographolide, isolated from Andrographis paniculata, induces apoptosis in monocytic leukemia and multiple myeloma cells via augmentation of reactive oxygen species production

Background: Andrographolide (Andro) is a diterpenoid component of the plant Andrographis paniculata that is known for its anti-tumor activity against a variety of cancer cells.  

Methods: We studied the effects of Andro on the viability of the human leukemia monocytic cell line THP-1 and the human multiple myeloma cell line H929. Andro was compared with cytosine arabinoside (Ara-C) and vincristine (VCR), which are well-established therapeutics against hematopoietic tumors. The importance of reactive oxygen species (ROS) production for the toxicity of each agent was investigated by using an inhibitor of ROS production, N-acetyl-L-cysteine (NAC).   

Results:  Andro reduced the viability of THP-1 and H929 in a concentration-dependent manner. H929 viability was highly susceptible to Andro, although only slightly susceptible to Ara-C. The agents Andro, Ara-C, and VCR each induced apoptosis, as shown by cellular shrinkage, DNA fragmentation, and increases in annexin V-binding, caspase-3/7 activity, ROS production, and mitochondrial membrane depolarization. Whereas Ara-C and VCR increased the percentages of cells in the G0/G1 and G2/M phases, respectively, Andro showed little or no detectable effect on cell cycle progression. The apoptotic activities of Andro were largely suppressed by NAC, an inhibitor of ROS production, whereas NAC hardly affected the apoptotic activities of Ara-C and VCR. 

Conclusions: Andro induces ROS-dependent apoptosis in monocytic leukemia THP-1 and multiple myeloma H929 cells, underlining its potential as a therapeutic agent for treating hematopoietic tumors. The high toxicity for H929 cells, by a mechanism that is different from that of Ara-C and VCR, is encouraging for further studies on the use of Andro against multiple myeloma.

Advances in ameliorating inflammatory diseases and cancers by andrographolide: Pharmacokinetics, pharmacodynamics, and perspective

Andrographolide, a well-known natural lactone having a range of pharmacological actions in traditional Chinese medicine. It has long been used to cure a variety of ailments. In this review, we cover the pharmacokinetics and pharmacological activity of andrographolide which supports its further clinical application in cancers and inflammatory diseases. Growing evidence shows a good therapeutic effect in inflammatory diseases, including liver diseases, joint diseases, respiratory system diseases, nervous system diseases, heart diseases, inflammatory bowel diseases, and inflammatory skin diseases. As a result, the effects of andrographolide on immune cells and the processes that underpin them are discussed. The preclinical use of andrographolide to different organs in response to malignancies such as colorectal, liver, gastric, breast, prostate, lung, and oral cancers has also been reviewed. In addition, several clinical trials of andrographolide in inflammatory diseases and cancers have been summarized. This review highlights recent advances in ameliorating inflammatory diseases as well as cancers by andrographolide and its analogs, providing a new perspective for subsequent research of this traditional natural product.

Andrographolide derivative as antagonist of vitamin D receptor to induce lipidation of microtubule associate protein 1 light chain 3 (LC3)

Lipidation of microtubule associated protein 1 light chain 3 (LC3) is the critical step in autophagosome formation, numerous efforts have been made to design and develop small molecules that trigger LC3 lipidation to activate autophagy. In this study, we discovered a series of andrographolide derivatives as potent antagonists of vitamin D receptor (VDR) by luciferase reporter assay. Structure-activity-relationship study revealed that andrographolide derivative ZAV-12 specifically inhibited VDR signaling but not NF-κB or STAT3 activation. Western blot analysis indicates that ZAV-12 markedly triggered lipidation of LC3 in MPP⁺-induced Parkinsonism in vitro in an mTOR-independent manner. The ZAV-12 triggered lipidation was mediated through SREBP2 activation instead of changing expression levels of lipid synthesis genes. Furthermore, ZAV-12 treatment increased the ratio of LC3-II/LC3-I and oligomerization of A53T α-synuclein (SNCA) in SNCA triggered neurotoxicity. Taken together, these results demonstrate the therapeutic potential of VDR antagonist as novel drug candidate for neurodegenerative diseases.

Biological properties of andrographolide, an active ingredient of Andrographis Paniculata: a narrative review

Andrographolide is a labdane diterpenoid isolated from Andrographis paniculata and traditionally used in Chinese and Indian medicine. Reported effects include anti-bacterial, anti-inflammatory and anti-cancer functions. Most of the studies support the hypothesis that andrographolide supplementation stimulates immune system, so the observed effects migh in fact be secondary to the stimulation of defense reactions. As andrographolide is involved in regulation of inflammation, it is not surprising that it is also evaluated in inflammation-mediated diseases such as ulcerative colitis. Anticancer effects of the andrographolide have been tested on various cancer panels. Colon cancer, breast cancer, and head and neck carcinomas were the most investigated, followed by prostate cancer and glioblastoma. The results looked promising. However, problems with solubility and low level of active substance in natural extract leads to preparation of chemical analogs. Objective of this short review is to summarize current knowledge of the biological effects of andragrapholide. We conclude that despite documented effects and some partly characterized mechanisms of action, more research is clearly needed. At present, the doses, types of treatment and possible negative side effects are not yet established. In addition, various isolations and compound formulas have been used for treatment of various diseases, making final conclusions problematic.

Andrographolide and its derivatives: Current achievements and future perspectives

Natural product andrographolide isolated from the plant Andrographis paniculata shows a plethora of biological activities, including anti-tumor, anti-bacterial, anti-inflammation, anti-virus, anti-fibrosis, anti-obesity, immunomodulatory and hypoglycemic activities. Based on extensive chemical structural modifications, a series of andrographolide derivatives with improved bioavailability and druggability has been developed. Moreover, greater understanding of their mechanisms of action at the molecular and cellular level has been thoroughly investigated. In this review, we give an outlook for the therapeutical potential of andrographolide and its derivatives in diverse diseases and highlighted the drug design, pharmacokinetic and mechanistic studies for the past ten years, together with a brief overview of the pharmacological effects. Notably, we focused to provide a critical enlightenment of the area of andrographolide and its derivatives with the intent of indicating the future perspectives, challenges and limitations. We believe that this review paper will benefit drug discovery where andrographolide was used as a template, shed light on the identification of drug targets for andrographolide and its analogs, as well as increase our knowledge for using them for therapeutic application, including the treatment for various forms of cancers.

Andrographolide binds to spike glycoprotein and RNA-dependent RNA polymerase (NSP12) of SARS-CoV-2 by in silico approach: a probable molecule in the development of anti-coronaviral drug

The SARS-CoV-2 belongs to Coronaviridae family infects host cells by the interaction of its spike glycoprotein and angiotensin-converting enzyme 2 (ACE 2) of host cells. Upon entry, the virus uses its RNA dependent RNA polymerase (NSP12) for transcribing its genome to survive in the cell and spread its infection. The protein sequences of receptor-binding domain (RBD) of spike glycoprotein, and NSP12 exhibits high homology in the family of Coronoviridae and are ideal candidates for the development of anti-coronaviral drugs. In the quest to identify inhibitory molecules against these proteins, we searched several molecules that are present in naturally occurring medicinal plants database. Andrographolide which is largely present in the leaf extracts of Andrographis paniculata (AP) and is known to exhibit antiviral, antibacterial, and stabilizes Th1/Th2/Th17 responses; taking this clue, we used in silico approaches to see the binding of andrographolide to RBD and NSP12 molecules. Our docking results showed very strong affinity of andrographolide to RBD and NSP12 of the SARS-CoV-2 virus with dock scores of -10.3460 for RBD and -10.7313 for NSP12 indicating andrographolide acts as an inhibitor of RBD and NSP12. These unique properties of andrographolide, AP extract, can be tested as anti-coronaviral drug.

Calming the Storm: Natural Immunosuppressants as Adjuvants to Target the Cytokine Storm in COVID-19

The COVID-19 pandemic has caused a global health crisis, with no specific antiviral to treat the infection and the absence of a suitable vaccine to prevent it. While some individuals contracting the SARS-CoV-2 infection exhibit a well coordinated immune response and recover, others display a dysfunctional immune response leading to serious complications including ARDS, sepsis, MOF; associated with morbidity and mortality. Studies revealed that in patients with a dysfunctional immune response, there is a massive cytokine and chemokine release, referred to as the 'cytokine storm'. As a result, such patients exhibit higher levels of pro-inflammatory/modulatory cytokines and chemokines like TNFα, INFγ, IL-1β, IL-2, IL-4, IL-6, IL-7, IL-9, IL-10, IL-12, IL-13, IL-17, G-CSF, GM-CSF, MCSF, HGF and chemokines CXCL8, MCP1, IP10, MIP1α and MIP1β. Targeting this cytokine storm is a novel, promising treatment strategy to alleviate this excess influx of cytokines observed at the site of infection and their subsequent disastrous consequences. Natural immunosuppressant compounds, derived from plant sources like curcumin, luteolin, piperine, resveratrol are known to inhibit the production and release of pro-inflammatory cytokines and chemokines. This inhibitory effect is mediated by altering signal pathways like NF-κB, JAK/STAT, MAPK/ERK that are involved in the production and release of cytokines and chemokines. The use of these natural immunosuppressants as adjuvants to ameliorate the cytokine storm; in combination with antiviral agents and other treatment drugs currently in use presents a novel, synergistic approach for the treatment and effective cure of COVID-19. This review briefly describes the immunopathogenesis of the cytokine storm observed in SARS-CoV-2 infection and details some natural immunosuppressants that can be used as adjuvants in treating COVID-19 disease.

Andrographolide inhibits secretagogue-induced pseudo-allergic reaction

Many kinds of drugs induce pseudo-allergic reactions due to activation of mast cells. We investigated the anti-pseudo-allergic effect of andrographolide (Andro). The effects of Andro on pseudo-allergic reactions were investigated in vivo and in vitro. Andro suppressed compound 48/80 (C48/80) induced pseudo-allergic reactions in mice in a dose-dependent manner. Andro also inhibited C48/80-induced local inflammatory reactions in mice. In vitro studies revealed that Andro reduced C48/80-induced mast cells degranulation. Human phospho-kinase array kit and western blotting showed that Andro could inhibit pseudo-allergic responses via the calcium signaling pathway.

Andrographolide and Its 14-Aryloxy Analogues Inhibit Zika and Dengue Virus Infection

Andrographolide is a labdene diterpenoid with potential applications against a number of viruses, including the mosquito-transmitted dengue virus (DENV). In this study, we evaluated the anti-viral activity of three 14-aryloxy analogues (ZAD-1 to ZAD-3) of andrographolide against Zika virus (ZIKV) and DENV. Interestingly, one analogue, ZAD-1, showed better activity against both ZIKV and DENV than the parental andrographolide. A two-dimension (2D) proteomic analysis of human A549 cells treated with ZAD-1 compared to cells treated with andrographolide identified four differentially expressed proteins (heat shock 70 kDa protein 1 (HSPA1A), phosphoglycerate kinase 1 (PGK1), transketolase (TKT) and GTP-binding nuclear protein Ran (Ran)). Western blot analysis confirmed that ZAD-1 treatment downregulated expression of HSPA1A and upregulated expression of PGK1 as compared to andrographolide treatment. These results suggest that 14-aryloxy analogues of andrographolide have the potential for further development as anti-DENV and anti-ZIKV agents.

Design, synthesis and discovery of andrographolide derivatives against Zika virus infection

The Zika endemic established by imported and local transmission is of significant concern and effective anti-ZIKV drugs remain an urgent unmet need. As andrographolide was identified to be an inhibitor of DENV and CHIKV and the importance of quinoline structure against infectious diseases was considered, we are interested in studying its andrographolide derivatives with quinoline moiety against Zika virus infection. In addition to screening eight in-house derivatives of andrographolide, sixteen new derivatives were designed, synthesized and tested against Zika virus infection. Among these compounds, two most potent anti-Zika compounds of 19-acetylated 14α-(5',7'-dichloro-8'-quinolyloxy) derivative 17b and 14β-(8'-quinolyloxy)-3,19- diol derivative 3 with the highest selectivity were discovered. The SAR analysis indicates that rational and optimal combined modification/s at 3-, 14-, or 19-positions can make derivatives less toxic and more potent against Zika infection, and both of 3 and 17b are suitable as leads for designing new generation of andrographolide derivatives with quinoline or its structure- and property-related moieties against Zika virus and other arboviruses.

Andrographolide Exerts Significant Antidepressant-Like Effects Involving the Hippocampal BDNF System in Mice

BACKGROUND

Major depressive disorder is a worldwide neuropsychiatric disorder associated with various symptoms, but current antidepressants used in clinical practice have various side effects and high failure rates. Andrographolide is the main bioactive ingredient of Andrographis paniculata and exhibits numerous pharmacological actions. This study aimed to evaluate the antidepressant-like effects of andrographolide in male C57BL/6J mice.

METHODS

The antidepressant-like effects of andrographolide in mice were explored in a forced swim test, tail suspension test, and chronic unpredictable mild stress model of depression. Western blotting and immunofluorescence were further performed to assess the effects of chronic unpredictable mild stress and andrographolide on the brain-derived neurotrophic factor signalling cascade and hippocampal neurogenesis. Moreover, a pharmacological inhibitor (K252a) and a lentiviral-short hairpin RNA (LV-TrkB-shRNA) were used to clarify the antidepressant-like mechanism of andrographolide.

RESULTS

Andrographolide exhibited antidepressant-like potential in the forced swim test and tail suspension test without influencing the locomotor activity of mice. Repeated andrographolide treatment not only produced significant antidepressant-like effects in the chronic unpredictable mild stress model but also prevented the decreasing effects of chronic unpredictable mild stress on hippocampal brain-derived neurotrophic factor signalling and neurogenesis in mice. Importantly, blockade of the hippocampal brain-derived neurotrophic factor system by K252a and TrkB-shRNA fully abolished the antidepressant-like effects of andrographolide in mice.

CONCLUSIONS

Andrographolide exerts antidepressant-like effects in mice via promoting the hippocampal brain-derived neurotrophic factor signalling cascade.

2-O-β-d-glucopyranosyl-l-ascorbic acid, a novel vitamin C derivative from Lycium barbarum, prevents oxidative stress

Reducing agents are crucial for the management of maladaptive inflammation-induced macrophage death and hematopoietic toxicity of chemotherapy. 2-O-β-d-glucopyranosyl-_l-ascorbic acid (AA-2βG), a unique AA (or vitamin C) derivative identified in Lycium barbarum, exhibited enhanced free radical scavenging activity compared with AA and its synthetic derivative AA-2αG. AA-2βG protected hydrogen peroxide-induced cell death in murine macrophage RAW264.7 cells. Treatment with AA-2βG eliminated oxidative stress and the ratio of cellular glutathione to glutathione disulfide more effectively than AA and AA-2αG. AA-2βG also significantly reduced the fluorescent intensity of DCFH-DA triggered by chemotherapeutic agent camptotehcin-11 but not fluorouracil. AA, AA-2αG, and AA-2βG significantly decreased Keap-1expression, and increased the expression levels of nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1. All compounds triggered the nuclear translocation of Nrf2, while the ability of AA-2βG to enhance the Nrf2-DNA binding affinity was approximately two fold as those of AA and AA-2αG. Sodium ascorbate cotransporters (SVCT) inhibitors, sulfinpyrazone, phloretin, and 3-O-methyglucose, potently abrogated the free radical scavenging activities of AA, AA-2αG, and AA-2βG. The cellular uptake efficacy of AA-2αG and AA-2βG was less than 10% of AA, while the inhibition of SVCT with sulfinpyrazone considerably diminished the uptake efficacy of these compounds. AA-2αG and AA-2βG are more stable in the Fenton reagents than AA. In summary, AA-2βG from L. barbarum with excellent free radical scavenging activity is a promising natural AA derivative for further pharmacological evaluation.

Overview of pharmacological activities of Andrographis paniculata and its major compound andrographolide

Andrographis paniculata (A. paniculata) is a medicinal plant traditionally used as anti-inflammation and anti-bacteria herb. Andrographolide, the major active component of A. paniculata, exhibits diverse pharmacological activities, including anti-inflammation, anti-cancer, anti-obesity, anti-diabetes, and other activities. In this article, we comprehensively review the therapeutic potential of A. paniculata and andrographolide focusing on the mechanisms of action and clinical application. We systemically discuss the structure-activity relationship of andrographolide and derivatives. Despite the various pharmacological activities and formula of A. paniculata and andrographolide, we propose further development of more structural derivatives of andrographolide with reduced toxicity and increased therapeutic efficacy is still needed for the clinical application of this ancient mighty herb and its major component.

Andrographolide derivative as STAT3 inhibitor that protects acute liver damage in mice

Sustained activation of the Janus kinase-signal transducers and activators of transcription (JAK-STAT) pathway contributed to the progression of cancer and liver diseases. STAT3 signaling inhibitor has been extensively investigated for pharmacological use. We synthesized a series of andrographolide derivatives, and characterized their activity against STAT3 signaling pathway both in vitro and in the CCl₄-induced acute liver damage mice model. Among these derivatives, compound 24 effectively inhibited phosphorylation and dimerization of STAT3 but not its DNA binding activity. Compound 24 significantly ameliorated carbon tetrachloride-induced acute liver damage in vivo without changing mice body weight. Treatment with 24 attenuated hepatic pathologic damage and promoted hepatic proliferation and activation of STAT3. Compound 24 inhibited elevated expression of α-smooth muscle actin and serum pro-inflammatory cytokines downstream of STAT3 but not those factors that are regulated by NF-κB or SMADs. In summary, our results suggest that compound 24 may serve as a potential therapeutic agent for the treatment of hepatic damage or a liver protection agent via regulating STAT3 activation.

Andrographolide Ameliorates Diabetic Cardiomyopathy in Mice by Blockage of Oxidative Damage and NF-κB-Mediated Inflammation

Andrographolide (Andro), a major bioactive component obtained from Andrographis paniculata Nees, has exerted wide antioxidant as well as cytoprotective properties. However, whether Andro treatment could retard the progress of diabetic cardiomyopathy (DCM) remains unknown. In this study, we evaluated the effects of Andro against diabetes-induced myocardial dysfunction and explored the underlying mechanism in STZ-induced diabetic mice. As a result, treatment with Andro dose dependently suppressed cardiac inflammation and oxidative stress, accompanied by decreasing cardiac apoptosis, which subsequently ameliorated cardiac fibrosis and cardiac hypertrophy. Further, Andro blocked hyperglycemia-triggered reactive oxygen species (ROS) generation by suppressing NADPH oxidase (NOX) activation and augmenting nuclear factor erythroid 2-related factor 2 (Nrf2) expression both in vitro and in vivo. Our results suggest that the cardioprotective effects afforded by Andro treatment involve the modulation of NOX/Nrf2-mediated oxidative stress and NF-κB-mediated inflammation. The present study unravels the therapeutic potential of Andro in the treatment of DCM by attenuating oxidative stress, inflammation, and apoptosis.

Discovery and preliminary SAR of 14-aryloxy-andrographolide derivatives as antibacterial agents with immunosuppressant activity

Antibacterials (which restore gut flora balance) and immunosuppressants (which correct immune defects) are two important and effective therapeutic agents for the treatment of inflammatory bowel disease (IBD) in clinical use today. Since the structural skeleton of andrographolide, isolated from Andrographis paniculata, has become known as a natural antibiotic with anti-inflammation and heat-clearing and detoxifying properties, 14-aryloxy andrographolide derivatives have been designed, synthesized, and tested for their antibacterial effects on E. coli, S. aureus, and E. faecalis, which are related to IBD. It has been discovered in this study that the andrographolide skeleton is more selective against E. faecalis, the 14-aryloxy group with basicity is important for antibacterial functions, and the 14-(8'-quinolinyloxy) group is a good pharmacophore with antibacterial activity. In addition, we found that 7b1 and 8b1 are good and selective inhibitors of E. faecalis; two 14β-(8'-quinolinyloxy) andrographolide derivatives, 6b17 and 9b, exhibit good activity against E. coli, S. aureus, and E. faecalis. Likewise and importantly, further exploration of immunosuppressant activity for IBD shows that compound 7b1 is a selective inhibitor of the TNF-α/NF-κB signaling pathway, whereas 8b1 is selectively active against the TLR4/NF-κB signaling pathway; moreover, the compounds 6b17 and 9b are active in inhibiting the IL-6/STAT3, TLR4/NF-κB, and TNF-α/NF-κB signaling pathways. Based on these results, we have further focused on the development of dual function inhibitors of IBD as antibacterial and immunosuppressant agents by structural modification of andrographolide.