Phyllanthin of Standardized Phyllanthus amarus Extract Attenuates Liver Oxidative Stress in Mice and Exerts Cytoprotective Activity on Human Hepatoma Cell Line

An insight into the potent medicinal plant Phyllanthus amarus Schum. and Thonn

Phyllanthus amarus Schum. and Thonn., a globally distributed herb is known for its several therapeutic potentials. P. amarus has a long history of use in the traditional system of medicine for over 2000 years owing to its wide array of secondary metabolites that confer significant medicinal attributes. Research on various aspects including ethnobotany, phytochemistry to bioactivity, or pharmacological studies has been conducted over the past several decades on this potent herb. P. amarus extracts have shown a broad range of pharmacological activities like hepatoprotective, antioxidant, antiviral, antimicrobial, antidiabetic, anti-inflammatory, anticancer, antimalarial, nephroprotective, diuretic, and several other properties. The present review compiles and covers literature and research of several groups across past decades to date and focuses on how the therapeutic significance of this plant can be further explored for future research either as herbal formulations, alternative medicine, or in the pharmaceutical industry.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13237-022-00409-z.

Comparative Profiling of Four Lignans (Phyllanthin, Hypophyllanthin, Nirtetralin, and Niranthin) in Nine Phyllanthus Species from India Using a Validated Reversed Phase HPLC-PDA Detection Method

BACKGROUND

Phyllanthus species exhibit a wide range of in vitro and in vivo pharmacological activities; however, little is known about the compounds present in the extracts that are responsible for such actions.

OBJECTIVE

Development and validation of a simple reversed phase HPLC-PDA method for profiling of phyllanthin, hypophyllanthin, nirtetralin, and niranthin in extracts of Phyllanthus species was carried out.

METHODS

Separation was achieved using an XBridge column® (150 × 4.6 mm, 5.0 µm id) in an isocratic elution mode with mobile phase comprising of a mixture of acetonitrile and water with TFA (0.05%, v/v, pH = 2.15) at ambient temperature with a flow rate of 1 mL/min.

RESULTS

Phyllanthin, hypophyllanthin, nirtetralin, and niranthin were eluted at mean retention times of 10.47, 11.10, 13.67, and 14.53 min, respectively. LOD and LOQ for all four analytes were 0.75 and 3.00 μg/mL, respectively. RSDr values for intraday and interday precision for phyllanthin, hypophyllanthin, nirtetralin, and niranthin were 0.38-1.32 and 0.45-1.77%; 0.22-3.69 and 0.24-3.04%, 0.73-2.37 and 0.09-0.31%, and 1.56-2.77 and 0.12-0.68%, respectively.

CONCLUSIONS

The developed and validated HPLC-PDA method was applied for identification and quantification of phyllanthin, hypophyllanthin, nirtetralin, and niranthin in extracts of different plant parts of selected Phyllanthus species. The outcome of the present investigation could be useful for selection of best species to promote its commercial cultivation and suitable extraction solvent for preparation of lignan-enriched fractions. This HPLC-PDA method could be useful for quality control of herbal formulations containing plants from Phyllanthus species.

Modulation of non-steroidal anti-inflammatory drug-induced, ER stress-mediated apoptosis in Caco-2 cells by different polyphenolic antioxidants: a mechanistic study

OBJECTIVES

Direct scavenging of reactive oxygen species could not prevent ER stress-associated cytotoxicity of indomethacin or diclofenac in Caco-2 cells. This study investigated the effects of three polyphenolic antioxidants epigallocatechin gallate (EGCG), phyllanthin and hypophyllathin in non-steroidal anti-inflammatory drug-induced Caco-2 apoptosis.

METHODS

Cells were treated with ER stressors (indomethacin, diclofenac, tunicamycin or thapsigargin) and the polyphenols for up to 72 h. Cell viability, apoptosis and mitochondrial function were monitored by MTT, Hoechst 33342 and TMRE assays, respectively. Protein expression was measured by Western blot analysis.

KEY FINDINGS

Epigallocatechin gallate suppressed increases in p-PERK/p-eIF-2α/ATF-4/CHOP and p-IRE-1α/p-JNK1/2 expression levels in the cells treated with any of the ER stressors, leading to inhibition of apoptosis. In contrast, phyllanthin increased apoptosis in the cells subsequently exposed to either diclofenac, tunicamycin or thapsigargin, but not in the indomethacin-treated cells. The potentiation effect of phyllanthin seen with the three ER stressors was related to suppression of survival p-Nrf-2/HO-1 expression, resulting in increased activation of the eIF-2α/ATF-4/CHOP pathway. On the other hand, hypophyllanthin had no significant effect on the ER stressor-induced apoptosis.

CONCLUSION

Epigallocatechin gallate, phyllanthin and hypophyllanthin displayed different effects in the ER stress-mediated apoptosis, depending upon their interaction with the specific unfolded protein response signalling.

Phyllanthin and hypophyllanthin from Phyllanthus amarus ameliorates immune-inflammatory response in ovalbumin-induced asthma: role of IgE, Nrf2, iNOs, TNF-α, and IL's

Background: Asthma is a chronic airway immunoinflammatory disorder characterized by airway remodeling. Phyllanthus amarus has been reported to possess antioxidant and anti-inflammatory potential. Aim: To evaluate the possible mechanism of action of isolated phytoconstituents from P. amarus (PA) against ovalbumin (OVA)-induced experimental airway hyperresponsiveness (AHR). Material and method: Phyllanthin and hypophyllanthin were isolated and characterized (HPLC) from the methanolic extract of PA. AHR was induced in Sprague-Dawley rats by OVA-challenged, and animals were treated with PA (50, 100, and 200 mg/kg, p.o.) for 28 days. Results: The HPLC analysis showed the presence of phyllanthin and hypophyllanthin in methanolic extract of PA at RT of 25.243 and 26.832 min, respectively. OVA-induced alterations in hemodynamic parameters, lung functions test, peripheral blood oxygen level, total, and differential cell count in Bronchoalveolar Lavage Fluid was significantly attenuated (p < .05) by PA (100 and 200 mg/kg). It also significantly decreased (p < .05) the levels of total protein and albumin in serum, BALF, and lungs. OVA-induced increase in IgE (total and OVA-specific), and oxido-nitrosative stress (SOD, GSH, MDA, and NO) levels were significantly (p < .05) decreased by PA. RT-PCR analysis revealed that elevated oxido-nitrosative stress (Nrf2 and iNOs), immune-inflammatory makers (HO-1, TNF-α, IL-1β, and TGF-β1), Th2 cytokines (IL-4 and IL-6) levels were significantly attenuated (p < .05) by PA. PA also attenuated histological and ultrastructural aberrations induced by OVA. Conclusion: Results of the present investigation demonstrated that the presence of phyllanthin and hypophyllanthin in P. amarus alleviated Th2 response in OVA-induced AHR via modulation of endogenous markers in a murine model of asthma. Thus, phyllanthin and hypophyllanthin may be a new therapeutic approach for the management of asthma.

Development of NASH in Obese Mice is Confounded by Adipose Tissue Increase in Inflammatory NOV and Oxidative Stress

AIM

Nonalcoholic steatohepatitis (NASH) is the consequence of insulin resistance, fatty acid accumulation, oxidative stress, and lipotoxicity. We hypothesize that an increase in the inflammatory adipokine NOV decreases antioxidant Heme Oxygenase 1 (HO-1) levels in adipose and hepatic tissue, resulting in the development of NASH in obese mice.

METHODS

Mice were fed a high fat diet (HFD) and obese animals were administered an HO-1 inducer with or without an inhibitor of HO activity to examine levels of adipose-derived NOV and possible links between increased synthesis of inflammatory adipokines and hepatic pathology.

RESULTS

NASH mice displayed decreased HO-1 levels and HO activity, increased levels of hepatic heme, NOV, MMP2, hepcidin, and increased NAS scores and hepatic fibrosis. Increased HO-1 levels are associated with a decrease in NOV, improved hepatic NAS score, ameliorated fibrosis, and increases in mitochondrial integrity and insulin receptor phosphorylation. Adipose tissue function is disrupted in obesity as evidenced by an increase in proinflammatory molecules such as NOV and a decrease in adiponectin. Importantly, increased HO-1 levels are associated with a decrease of NOV, increased adiponectin levels, and increased levels of thermogenic and mitochondrial signaling associated genes in adipose tissue.

CONCLUSIONS

These results suggest that the metabolic abnormalities in NASH are driven by decreased levels of hepatic HO-1 that is associated with an increase in the adipose-derived proinflammatory adipokine NOV in our obese mouse model of NASH. Concurrently, induction of HO-1 provides protection against insulin resistance as seen by increased insulin receptor phosphorylation. Pharmacological increases in HO-1 associated with decreases in NOV may offer a potential therapeutic approach in preventing fibrosis, mitochondrial dysfunction, and the development of NASH.

Insect tea extract attenuates CCl4-induced hepatic damage through its antioxidant capacities in ICR mice

The Insect tea extract (ITE) contained many polyphenols, the aim of the present study was to determine the preventive effects of ITE on CCl₄-induced hepatic damage in mice. ITE treated mice could reduce hepatic injury compared to the control mice. The 200 mg/kg ITE increased TC, ALB, SOD, CAT, GSH-Px serum levels, and decreased ALT, AST, ALP, TG, BUN, NO, MDA levels compared to the control group. By histological observation, ITE reduced injury to hepatic cells, and these effects were close to that seen with the drug silymarin. The antioxidant related mRNA and protein expressions of Mn SOD, Gu/Zn SOD, CAT, and GSH-Px increased with ITE treatment in hepatic damage mice. ITE treated mice also showed higher IκB-α mRNA and protein expression, and lower NF-κB-p65, iNOS, COX-2 expressions than those of control mice. These results proved ITE has a prophylactic effect in protecting against hepatic injury through the antioxidant capacities.

Phyllanthin inhibits CCl4-mediated oxidative stress and hepatic fibrosis by down-regulating TNF-α/NF-κB, and pro-fibrotic factor TGF-β1 mediating inflammatory signaling

Hepatic fibrosis is an important outcome of chronic liver injury and results in excess synthesis and accumulation of extracellular matrix (ECM) components. Phyllanthin (PLN) isolated from Phyllanthus amarus exhibits strong antioxidative property and protects HepG2 cells from carbon tetrachloride (CCl4)-induced experimental toxicity. The present study reports the antifibrotic potential of PLN. The in vivo inhibitory effect of PLN on CCl4-mediated lipid peroxidation and important profibrotic mediator transforming growth factor β1 and on predominant ECM components collagen and fibronectin were also studied. The results show that PLN acts by suppressing the expression of inflammatory cytokine tumor necrosis factor-α and prevents activation of nuclear factor-κB in hepatic tissue. Our study highlights the molecular mechanism responsible for the antifibrotic efficacy of PLN.

Protective effect of dieckol isolated from Ecklonia cava against ethanol caused damage in vitro and in zebrafish model

In the present study, the protective effects of phlorotannins isolated from Ecklonia cava against ethanol-induced cell damage and apoptosis were investigated both in vitro and in vivo. Three phlorotannin compounds, namely phloroglucinol, eckol and dieckol, were successively isolated and identified from the extract. Dieckol showed the strongest protective effect against ethanol-induced cell apoptosis in Chang liver cells, with the lowest cytotoxicity. It was observed that dieckol reduced cell apoptosis through activation of Bcl-xL and PARP, and down-regulation of Bax and caspase-3 in Western blot analyses. In the in vivo study, the protective effect of ethanol induced by dieckol was investigated in a zebrafish model. The dieckol treated group scavenged intracellural reactive oxygen species and prevented lipid peroxidation and ethanol induced cell death in the zebrafish embryo. In conclusion, dieckol isolated from E. cava might possess a potential protective effect against ethanol-induced liver diseases.