Protective effect of Premna tomentosa extract (L. verbanacae) on acetaminophen-induced mitochondrial dysfunction in rats

Acetaminophen induced hepatotoxicity: An overview of the promising protective effects of natural products and herbal formulations

BACKGROUND

The liver plays an important role in regulating the metabolic processes and is the most frequently targeted organ by toxic chemicals. Acetaminophen (APAP) is a well-known anti-allergic, anti-pyretic, non-steroidal anti-inflammatory drug (NSAID), which upon overdose leads to hepatotoxicity, the major adverse event of this over-the-counter drug.

PURPOSE

APAP overdose induced acute liver injury is the second most common cause that often requires liver transplantation worldwide, for which N-acetyl cysteine is the only synthetic drug clinically approved as an antidote. So, it was felt that there is a need for the novel therapeutic approach for the treatment of liver diseases with less adverse effects. This review provides detailed analysis of the different plant extracts; phytochemicals and herbal formulations for the amelioration of APAP-induced liver injury.

METHOD

The data was collected using different online resources including PubMed, ScienceDirect, Google Scholar, Springer, and Web of Science using keywords given below.

RESULTS

Over the past decades various reports have revealed that plant-based approaches may be a better treatment choice for the APAP-induced hepatotoxicity in pre-clinical experimental conditions. Moreover, herbal compounds provide several advantages over the synthetic drugs with fewer side effects, easy availability and less cost for the treatment of life-threatening diseases.

CONCLUSION

The current review summarizes the hepatoprotective effects and therapeutic mechanisms of various plant extracts, active phytoconstituents and herbal formulations with potential application against APAP induced hepatotoxicity as the numbers of hepatoprotective natural products are more without clinical relativity. Further, pre-clinical pharmacological research will contribute to the designing of natural products as medicines with encouraging prospects for clinical application.

Can natural products modulate cytokine storm in SARS-CoV2 patients?

Currently, the number of cases and deaths of SARS-CoV2, especially among the chronic disease groups, due to aggressive SARS-CoV2 infection is increasing day by day. Various infections, particularly viral ones, cause a cytokine storm resulting in shortness of breath, bleeding, hypotension, and ultimately multi-organ failure due to over-expression of certain cytokines and necrosis factors. The most prominent clinical feature of SARS-CoV2 is the presence of elevated proinflammatory cytokines in the serum of patients with SARS-CoV2. Severe cases exhibit higher levels of cytokines, leading to a "cytokine storm" that further increases disease severity and causes acute respiratory distress syndrome, multiple organ failure, and death. Therefore, targeted cytokine production could be a potential therapeutic option for patients severely infected with SARS-CoV2. Given the current scenario, great scientific progress has been made in understanding the disease and its forms of treatment. Because of natural ingredients properties, they have the potential to be used as potential agents with the ability to modulate immune responses. Moreover, they can be used safely because they have no toxic effects, are biodegradable and biocompatible. However, these natural substances can continue to be used in the development of new therapies and vaccines. Finally, the aim and approach of this review article is to highlight current research on the possible use of natural products with promising potential as immune response activators. Moreover, consider the expected use of natural products when developing potential therapies and vaccines.

Neuroprotective flavonoids of the leaf of Antiaris africana Englea against cyanide toxicity

ETHNOPHARMACOLOGICAL RELEVANCE

Different parts of Antiaris africana Englea (Moraceae) are used traditionally for the treatment of various diseases, including epilepsy and other nervous system disorders.

AIMS OF THIS STUDY

The current study was designed to evaluate the neuroprotective activity of flavonoids isolated from A. africana against potassium cyanide (KCN)-induced oxidative damage in brain homogenate.

MATERIALS AND METHODS

Dried and ground leaves of A. africana were extracted with methanol and fractioned into n-hexane (HFA), dichloromethane (DFA), ethyl acetate (EFA) and methanol (MFA). Each fraction was assessed for neuroprotective potential by anticholinesterase activity test. The fraction with the best anticholinesterase activity was subjected to various chromatographic techniques through bioassay-guided fractionation to isolate the bioactive compounds. The protective ability of the extract, fractions and compounds against Potassium cyanide (KCN)-induced mitochondrial damage in rat brain homogenate was evaluated. Structures of the isolated compounds were determined using 1D and 2D NMR, mass spectrometry and by comparison with literature data.

RESULTS AND DISCUSSION

The ethyl acetate fraction showed the best anticholinesterase activity with an IC₅₀ of 23.23 ± 1.12 μg/ml. Quercetin and a biflavonoid glucoside identified as 3'-4'-bisquercetin-3β-D-diglucoside from this fraction displayed a remarkable antioxidant activity in the DPPH assay and showed significant (P < 0.05) increase in the activity of dehydrogenase inhibited by KCN in a concentration dependent manner. However, quercetin was more effective in reducing the MDA level and acetylcholinesterase activity that were elevated by KCN.

CONCLUSION

Quercetin and the bisquercetin-diglucoside isolated from the leaves of A. Africana for the first time, are major contributors to the observed neuroprotective property of the plant which supports its folkloric usage in the management of seizures, epilepsy and other neurological disorders.

Can limonene be a possible candidate for evaluation as an agent or adjuvant against infection, immunity, and inflammation in COVID-19?

Coronavirus disease (COVID-19) caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an ongoing pandemic and presents a public health emergency. It has affected millions of people and continues to affect more, despite the tremendous social preventive measures. The therapeutic strategy relies on suppressing infectivity and inflammation, along with immune modulation. The identification of candidate drugs effective for COVID-19 is crucial, thus many natural products including phytochemicals are also being proposed for repurposing and evaluated for their potential in COVID-19. Among numerous phytochemicals, limonene (LMN), a dietary terpene of natural origin has been recently showed to target viral proteins in the in-silico studies. LMN is one of the main compounds identified in many citrus plants, available and accessible in diets and well-studied for its therapeutic benefits. Due to dietary nature, relative safety and efficacy along with favorable physicochemical properties, LMN has been suggested to be a fascinating candidate for further investigation in COVID-19. LMN showed to modulate numerous signaling pathways and inhibits inflammatory mediators, including cytokines, chemokines, adhesion molecules, prostanoids, and eicosanoids. We hypothesized that given the pathogenesis of COVID-19 involving infection, inflammation, and immunity, LMN may have potential to limit the severity and progression of the disease owing to its immunomodulatory, anti-inflammatory, and antiviral properties. The present article discusses the possibilities of LMN in SARS-CoV-2 infections based on its immunomodulatory, anti-inflammatory, and antiviral properties. Though, the suggestion on the possible use of LMN in COVID-19 remains inconclusive until the in-silico effects confirmed in the experimental studies and further proof of the concept studies. The candidature of LMN in COVID-19 treatment somewhat appear speculative but cannot be overlooked provided favorable physiochemical and druggable properties. The safety and efficacy of LMN are necessary to be established in preclinical and clinical studies before making suggestions for use in humans.

Hassan H. Anti-Inflammatory and Antioxidant Activities of Terpene- and Polyphenol-Rich Premna odorata Leaves on Alcohol-Inflamed Female Wistar Albino Rat Liver

Premna odorata Blanco (Lamiaceae) is an ethnomedicinal plant native to different tropical regions. Although some reports addressed their anti-inflammatory, cytotoxic, and antituberculotic effects, their hepatoprotective potential is yet to be discovered. Accordingly, this study investigated the crude extract and different fractions of the plant leaves; metabolic profiling using liquid chromatography/high-resolution electrospray ionization mass spectroscopy (LC–HRESIMS) analysis, in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties for the dereplicated metabolite via online PreADMET program, ROS scavenger activity on the Hep G2 human liver cancer cell line, and the possible hepatic cellular treatment effects in alcohol-inflamed liver female Wistar albino rats. Metabolic profiling dereplicated a total of 28 metabolites from the crude extract and its various fractions. In silico ADMET and ROS scavenger activity screening suggested plant metabolites are of potential bioactivity. In vivo hepatic treatment with crude, defatted crude, and n-hexane leave extracts suggested all extracts significantly improved liver damage, which was indicated by the reduction of elevated serum levels of bilirubin, AST, ALT, ALP, CRP, TNF-α, ICAM-1, VCAM-1, and MDA. The reduced levels of GSH and TAC were normalized during the study. Histological examinations of liver tissue showed collagen fiber distribution nearly back to its normal pattern. The anti-inflammatory and antioxidant potentials of Premna odorata extracts could be partly related to the combined effects of these phytochemicals or their synergistic interactions.

Ethnomedicinal uses, phytochemistry and pharmacological aspects of the genus Premna: a review

CONTEXT

The genus Premna (Lamiaceae), distributed throughout tropical and subtropical Asia, Africa, Australia and the Pacific Islands, is used in folk medicine primarily to treat inflammation, immune-related diseases, stomach disorders, wound healing, and skin diseases.

OBJECTIVES

This review exhaustively gathers available information on ethnopharmacological uses, phytochemistry, and bioactivity studies on more than 20 species of Premna and critically analyzes the reports to provide the perspectives and directions for future research for the plants as potential source of drug leads and pharmaceutical agents.

METHODS

A literature search was performed on Premna species based on books of herbal medicine, major scientific databases including Chemical Abstract, Pubmed, SciFinder, Springerlink, Science Direct, Scopus, the Web of Science, Google Scholar, and ethnobotanical databases.

RESULTS

More than 250 compounds have been isolated and identified from Premna species, comprising of diterpenoids, iridoid glycosides, and flavonoids as the most common secondary metabolites, followed by sesquiterpenes, lignans, phenylethanoids, megastigmanes, glyceroglycolipids, and ceramides. Many in vitro and in vivo studies have been conducted to evaluate the biological and pharmacological properties of the extracts, and isolated compounds of Premna species with antimicrobial, antioxidant, anti-inflammatory, immunomodulatory, antihyperglycaemia, and cytotoxic activities.

CONCLUSION

The bioactive compounds responsible for the bioactivities of most plants have not been well identified as the reported in vivo pharmacological studies were mostly carried out on the crude extracts. The isolated bioactive components should also be further subjected to more preclinical studies and elaborate toxicity study before clinical trials can be pursued.

Curcumin prevents paracetamol-induced liver mitochondrial alterations

OBJECTIVE

In the present study was evaluated if curcumin is able to attenuate paracetamol (PCM)-induced mitochondrial alterations in liver of mice.

METHODS

Mice (n = 5-6/group) received curcumin (35, 50 or 100 mg/kg bw) 90 min before PCM injection (350 mg/kg bw). Plasma activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) was measured; histological analyses were done; and measurement of mitochondrial oxygen consumption, mitochondrial membrane potential, ATP synthesis, aconitase activity and activity of respiratory complexes was carried out.

KEY FINDINGS

Curcumin prevented in a dose-dependent manner PCM-induced liver damage. Curcumin (100 mg/kg) attenuated PCM-induced liver histological damage (damaged hepatocytes from 28.3 ± 7.7 to 8.3 ± 0.7%) and increment in plasma ALT (from 2300 ± 150 to 690 ± 28 U/l) and AST (from 1603 ± 43 to 379 ± 22 U/l) activity. Moreover, curcumin attenuated the decrease in oxygen consumption using either succinate or malate/glutamate as substrates (evaluated by state 3, respiratory control ratio, uncoupled respiration and adenosine diphosphate/oxygen ratio), in membrane potential, in ATP synthesis, in aconitase activity and in the activity of respiratory complexes I, III and IV.

CONCLUSIONS

These results indicate that the protective effect of curcumin in PCM-induced hepatotoxicity is associated with attenuation of mitochondrial dysfunction.

Hepatoprotective effects of DL-α-lipoic acid and α-Tocopherol through amelioration of the mitochondrial oxidative stress in acetaminophen challenged rats

Acetaminophen (APAP) is known to induce liver mitochondrial dysfunction leading to acute hepatotoxicity. Effect of DL-α-lipoic acid (LA) and α-tocopherol (α-Toc) against the APAP-induced liver mitochondrial damage was evaluated in rats. LA (100 mg/kg, p.o.) and α-Toc (100 mg/kg, p.o.) were given once daily for 15 d, prior to the APAP administration (3 g/kg, p.o). Hepatic damage was confirmed by determining the activities of serum glutamate pyruvate transaminase, serum glutamate oxaloacetate transaminase and alkaline phosphatase, 4 h after the single dose of APAP. To assess the mitochondrial damage, the activities of antioxidant enzymes, Krebs' cycle dehydrogenases and mitochondrial electron transport chain complexes, and levels of reactive oxygen species (ROS), reduced glutathione, lipid peroxidation (malondialdehyde, MDA) as well as the mitochondrial membrane potential (Δψmt) were evaluated. The activities of mitochondrial enzymes and Δψmt were significantly (p < 0.01) decreased and the level of ROS and MDA were significantly (p < 0.01) increased due to APAP challenge. LA and α-Toc treatment significantly enhanced the activities of mitochondrial enzymes and Δψmt than that of control group; whereas the levels of ROS and MDA were decreased. The results of the study concluded that the liver damage induced by APAP was significantly ameliorated by LA and α-Toc. LA showed more protection than that of α-Toc. The protection can be partially ascribed to their mitochondrial protective effects through their antioxidant activity which could decrease the level of ROS and by direct enhancement of Δψmt.

Essential oils of four Rwandese hepatoprotective herbs: Gas chromatography-mass spectrometry analysis and antioxidant activities

Following an ethnobotanical survey in Southern Rwanda for hepatoprotective remedies, four food and medicinal plants, Crassocephalum vitellinum, Guizotia scabra, Microglossa pyrifolia and Ocimum lamiifolium, were selected for pharmacological and chemical investigations aiming to validate their reported properties. The chemical compositions of essential oils obtained from leaves were investigated by GC-MS; essential oils and methanolic extracts were evaluated for antioxidant activity by 1,1-diphenyl-2-picryhydrazyl (DPPH) and linoleic acid peroxidation assays. C. vitellinum [limonene (34.8%), (E)-β-ocimene (21.8%), β-pinene (8.5%), α-pinene (6.6%), myrcene (6.3%)], G. scabra [germacrene-d (25.5%), limonene (9.7%), (E)-β-ocimene (6.6%)], M. pyrifolia [germacrene-d (58.3%)] and O. lamiifolium [sabinene (12.2%), alpha phellandrene (11.6%)] volatile oils scavenge DPPH (10%, 39%, 27%, and 11% quercetin equivalents) and inhibit linoleic acid peroxidation (13%, 23%, 20%, and 13% Trolox® equivalents). The four methanolic extracts were quite active on the lipid peroxidation model (93%, 93%, 70%, and 67% Trolox equivalents) with modest activity on DPPH (5%, 10%, 8%, and 11% quercetin equivalents). These properties most probably participate in the four plants hepatoprotective activities reported in ethnopharmacological and/or pharmacological studies.

Screening of herbal medicines for recovery of acetaminophen-induced nephrotoxicity

This study was conducted to quantitatively evaluate the recovery effects of herbal medicines on acetaminophen-induced nephrotoxicity. In the present study, the recovery effects of 251 herb medicines on HEK 293 cells that had been damaged by acetaminophen were evaluated using an MTS assay. HEK 293 cells were cultured in 96-well plates and then pretreated with or without 20μM acetaminophen (IC(50) value: 17.5±1.9) for 1h. Next, different herbal medicines were added to the wells, after which the cells were reincubated at 37°C for 24h. After the first round of screening, the candidate herbal medicines were selected based on a recovery rate of greater than 20% and their efficacy were then determined by dose response kinetic analysis. Among these extracts, 8 herbal medicines (Ledebouriella divaricata, Sparganium simplex, Panax ginseng, Aster tataricus, Citrus aurantium, Sanguisorba officianlis, Arisaema consanguineum, and Polygonum aviculare) had a strong recovery effect on acetaminophen-induced damage in HEK 293 cells. Dose response non-linear regression analysis demonstrated that P. aviculare showed the best recovery rate (98%), and that its EC(50) (0.1ng/mL) was the smallest among the screened candidate herbal medicines. Additional studies of these herbal medicines should be conducted to determine if they possess novel therapeutic agents for the prevention or treatment of renal disorders.