Embelin as a Novel Inhibitor of PKC in the Prevention of Platelet Activation and Thrombus Formation

Demystifying the Potential of Embelin-Loaded Nanoformulations: a Comprehensive Review

Phytoconstituent based therapies have the potential to reduce the adverse effects and enhance overall patient compliance for different diseased conditions. Embelin (EMB) is a natural compound extracted from Embelia ribes that has demonstrated high therapeutic potential, particularly as anti-inflammatory and anticancer therapeutic applications. However, its poor water solubility and low oral bioavailability limitations make it challenging to use in biomedical applications. Nanostructure-based novel formulations have shown the potential to improve physicochemical and biological characteristics of active pharmaceutical ingredients obtained from plants. Different nanoformulations that have been utilized to encapsulate/entrap EMB for various therapeutic applications are nanoliposomes, nanostructured lipid carriers, niosomes, polymeric nanoparticles, nanosuspensions, phytosomes, self nanoemulsifying drug delivery system, silver nanoparticles, microparticles, solid lipid nanoparticle, gold nanoparticles and nanomicelles. The common methods reported for the preparation of EMB nanoformulations are thin film hydration, nanoprecipitation, ethanol injection, emulsification followed by sonication. The size of nanoformulations ranged in between 50 and 345 nm. In this review, the mentioned EMB loaded nanocarriers are methodically discussed for size, shape, drug entrapment, zeta potential, in vitro release & permeation and in vivo studies. Potential of EMB with other drugs (dual drug approach) incorporated in nanocarriers are also discussed (physicochemical and preclinical characteristics). Patents related to EMB nanoformulations are also presented which showed the clinical translation of this bioactive for future utilization in different indications.

Protective effects of Embelin in Benzo[α]pyrene induced cognitive and memory impairment in experimental model of mice

Alzheimer's disease (AD) is a neurodegenerative disease that affects the neurons in the hippocampus, resulting in cognitive and memory impairment. The most prominent clinical characteristics of AD are the production of amyloid-beta (Aβ) plaques, neurofibrillary tangles, and neuroinflammation in neurons. It has been proven that embelin (Emb) possesses antioxidant, anti-inflammatory, and neuroprotective properties. Therefore, we assessed the therapeutic potential of Emb in Benzo [α]pyrene (BaP)-induced cognitive impairment in experimental mice. BaP (5 mg/kg, i. p) was given to mice daily for 28 days, and Emb (2.5, 5, and 10 mg/kg, i. p) was given from 14 to 28 days of a protocol. In addition, locomotor activity was evaluated using open-field and spatial working, and non-spatial memory was evaluated using novel object recognition tasks (NORT), Morris water maze (MWM), and Y- maze. At the end of the study, the animal tissue homogenate was used to check biochemicals, neuroinflammation, and neurotransmitter changes. BaP-treated mice showed a significant decline in locomotor activity, learning and memory deficits and augmented oxidative stress (lipid peroxidation, nitrite, and GSH). Further, BaP promoted the release of inflammatory tissue markers, decreased acetylcholine, dopamine, GABA, serotonin, and norepinephrine, and increased glutamate concentration. However, treatment with Emb at dose-dependently prevented biochemical changes, improved antioxidant levels, reduced neuroinflammation, restored neurotransmitter concentration, and inhibited the NF-κB pathway. The current study's finding suggested that Emb improved cognitive functions through antioxidant, anti-inflammatory, and neuroprotective mechanisms and inhibition of acetylcholinesterase (AChE) enzyme activities and Aβ-42 accumulation.

'Vidangadi Lauha' for obese type 2 diabetes mellitus patients - An open-label randomized controlled clinical trial

BACKGROUND

Type 2 diabetes mellitus in obese persons is becoming alarming due to the increasing prevalence of its microvascular and macrovascular complications. Multi-targeted treatment can be considered better than single-targeted treatment because of the multiple pathways involved in the pathogenesis of diabetes and its complications.

OBJECTIVE

The study aimed to evaluate the efficacy of 'Vidangadi Lauha' (VL) (an Ayurveda formulation) compared with Metformin for obese type II diabetes mellitus.

METHODOLOGY

This is an open-label randomized controlled clinical study.Participants were divided into two groups. The trial Group received VL 5 gm BID, and the control group received tablet metformin (MT) 500 mg BID for three months.

RESULTS

VL showed reduction in HbA1c from 8.048(0.95) to 7.14(0.73), (CI, 0.7810 to 1.035; p < 0.0001) while MT showed reduction in HbA1C from 8.3(0.99) to7.18(0.67), (CI, 0.9220 to 1.305; p < 0.0001). VL showed improvement in the Quality of life instrument for the Indian Diabetes questionnaire(QOLID) score from 113.87(11.36) to 136.47(8.703) (CI, -25.68 to -19.52; p < 0.0001) as compared to MT 128.57(7.9) to 102.32(7.9), (CI, 23.19 to 29.39; p < 0.0001) VL showed reduction in bowel symptom questionnaire 30.275(8.077) to 13.2(1.265), (CI, 14.60-19.51; p < 0.0001) as compared to MT from 23.85(7.530) to 38.25(6.332), (CI, -15.99 to -12.80; p < 0.0001).

CONCLUSION

Both treatments were equally effective in reducing blood sugar fasting (F), post-meal (PM) glycated hemoglobin (HbA1C), and body mass index (BMI). VL is more effective than MT in reducing Ayurvedic symptoms, waist-hip ratio, cholesterol, quality of life, and bowel symptom questionnaire score.

Synthesis of Quinoline and Dihydroquinoline Embelin Derivatives as Cardioprotective Agents

A set of new dihydroquinoline embelin derivatives was obtained from the reaction of the natural benzoquinone embelin (1) with anilines and aromatic aldehydes in the presence of AgOTf. The synthesis of these compounds involves the formation of a Knoevenagel adduct, followed by nucleophilic addition of aniline and subsequent electrocyclic ring closure. The scope of the reaction regarding the aldehydes and anilines was determined. Quinoline derivatives were also obtained from the corresponding dihydroquinolines under oxidation with DDQ. The cardioprotective activity of the synthesized compounds was screened using a doxorubicin-induced cardiotoxicity model in H9c2 cardiomyocytes. Some structure-activity relationships were outlined, and the best activities were achieved with quinoline-embelin derivatives having a 4-nitrophenyl group attached at the pyridine ring. The obtained results indicated that embelin derivatives 4i, 6a, 6d, 6k, and 6m could have potential as cardioprotective agents, as they attenuated a DOX-induced cardiotoxicity effect acting on oxidative stress and apoptosis.

COVID-19 patient with B Cell Lymphoma co-morbidity managed with co-administration of Ayurvedic formulation

‘Renaissance took place in Chaos and plague’. It was COVID-19 pandemic, when world realized ayurveda co-interventions are praiseworthy even in acute, infective and fatal conditions like COVID-19. We report perhaps first case of COVID-19 patient with cancer managed with poly-herbal ayurvedic formulation and integrated approach. In the first wave of COVID-19 (June 2020), a 47 year old male with history of Chronic kidney disease and active B Cell Lymphoma complained of fever, malaise, cattarah and ageusia. He was found positive on RT-PCR which was done promptly and was later treated in home quarantine with antipyretics, Vitamin C and Madhav rasayan a polyherbal preparation containing Piper longum, Glycyrrhiza glabra, Eclipta alba, Achyranthes aspera, Embelia ribes and Aloe vera designed to modulate host response. It was challenging to treat a patient with cancer with immunocompromised status as he had recently finished his chemotherapy cycle (R–CHOP regimen). Patient well tolerated the intervention and recovered symptomatically. He did not developed any respiratory complications and oxygen saturation remained maintained. On 7th day RT-PCR was found to be negative. Plethora of literature is available on anti-viral and immunomodulatory efficacies of Ayurveda herbs based on in vitro studies. Such efficacies can be replicated at patient's level if supported with wisdom of Ayurveda epistemology. Early diagnosis on RT-PCR and early inception of ayurveda medicine and diet interventions might be crucial element for better recovery.

Embelin: A novel XIAP inhibitor for the prevention and treatment of chronic diseases

Chronic diseases are a serious health concern worldwide, especially in the elderly population. Most chronic diseases like cancer, cardiovascular ailments, neurodegenerative disorders, and autoimmune diseases are caused due to the abnormal functioning of multiple signaling pathways that give rise to critical anomalies in the body. Although a lot of advanced therapies are available, these have failed to entirely cure the disease due to their less efficacy. Apart from this, they have been shown to manifest disturbing side effects which hamper the patient's quality of life to the extreme. Since the last few decades, extensive studies have been done on natural herbs due to their excellent medicinal benefits. Components present in natural herbs target multiple signaling pathways involved in diseases and therefore hold high potential in the prevention and treatment of various chronic diseases. Embelin, a benzoquinone, is one such agent isolated from Embelia ribes, which has shown excellent biological activities toward several chronic ailments by upregulating a number of antioxidant enzymes (e.g., SOD, CAT, GSH, etc.), inhibiting anti-apoptotic genes (e.g., TRAIL, XIAP, survivin, etc.), modulating transcription factors (e.g., NF-κB, STAT3, etc.) blocking inflammatory biomarkers (e.g., NO, IL-1β, IL-6, TNF-α, etc.), monitoring cell cycle synchronizing genes (e.g., p53, cyclins, CDKs, etc.), and so forth. Several preclinical studies have confirmed its excellent therapeutic activities against malicious diseases like cancer, obesity, heart diseases, Alzheimer's, and so forth. This review presents an overview of embelin, its therapeutic prospective, and the molecular targets in different chronic diseases.

A comprehensive insight on the biological potential of embelin and its derivatives

Naturally occurring bioactive molecules are known for their diverse biological applications such as antimicrobial, anticancer, anti-inflammatory, and analgesic activities. Also, some of the natural products act as medicinal drugs. Further, bioactive cell-permeable molecule embelin has been reported for its diverse biological activities such as antimalarial, anticancer, and anti-inflammatory in the literature. With the continuation of our research work on biologically active molecules, based on structural activity relationship and docking studies of embelin and its derivatives, we have reported target-specific anticancer and antimalarial activities of embelin and its analogs. Also, it has been reported in many recent research articles that embelin and its derivatives are known to possess medicinal properties. This review mainly highlights recent reports on broad-spectrum biological activities of the embelin and its analogs to date.

Embelin's Versatile Photochemistry Makes It a Potent Photosensitizer for Photodynamic Therapy

Embelin, a natural product isolated from Embelia ribes, is a promising small-molecular drug for photodynamic anticancer therapy. Using modern quantum chemical methodology, embelin is shown to possess a versatile photochemistry comprising the capability of singlet oxygen generation, excited-state proton transfer, and oxidation. In particular, the detailed molecular mechanisms of singlet oxygen generation and proton transfer upon excitation are studied in great detail. While excited-state proton transfer can damage the protein itself, it also mediates intersystem crossing along its reaction pathway, thus facilitating singlet oxygen generation. When embelin is bound to proteins, all these processes can lead to protein damage and the desired phototoxicity.

Phytochemical analysis, antioxidant activities and optimized extraction of embelin from different genotypes of Embelia ribes Burm f.: a woody medicinal climber from Western Ghats of India

Medicinal importance of Embelia ribes Burm f. is known since ancient time. Its berries are the main ingredient in Vidanga' or 'Baibidanga'-a component of ayurvedic formulations and possess medicinal properties such as antihelmintic, anticancer, neuroprotective and antidiabetic. Studies were conducted on phytochemicals, antioxidant activities, extraction efficiency of embelin from ten genotypes. Methanolic extract of berries from Nagavelli accession exhibited the highest total phenolic content (18.18 ± 0.14 mg GAE/g DW); whereas, ethanolic extract showed highest total flavonoid content (8.35 ± 0.20 mg RE/g DW). The antioxidant activities (AOA) were assessed and noted that ethanolic and methanolic extracts of berries from Nagavelli (NAG) accession revealed highest activities in terms of DPPH radical scavenging activity (67.48 ± 0.17%) and FRAP (66.73 ± 0.60 mg Fe(II)/g DW), respectively. In AOA analysis, berries extracted with different solvents were positively correlated with TPC. Principal component analysis revealed TPC and TFC were the most influencing components for strong antioxidant activities in E. ribes. Reverse phase high performance liquid chromatography (RP-HPLC) was used to quantify embelin content and its optimize extraction using various methods. In the preliminary studies, berries from NAG accession revealed highest (1.770%) embelin content. Further, berries from NAG accession were subjected to various extraction methods and found three fold increase (5.08%) in embelin content in microwave assisted extraction (90 s). Present study suggested that NAG accession found to be a promising source of natural antioxidants and embelin that can be used in pharmaceutical industries.

Efficient Multicomponent Synthesis of Diverse Antibacterial Embelin-Privileged Structure Conjugates

A library of embelin derivatives has been synthesized through a multicomponent reaction from embelin (1), aldehydes and privileged structures such as 4-hydroxycoumarin, 4-hydroxy-2H-pyran-2-one and 2-naphthol, in the presence of InCl₃ as catalyst. This multicomponent reaction implies Knoevenagel condensation, Michael addition, intramolecular cyclization and dehydration. Many of the synthesized compounds were active and selective against Gram-positive bacteria, including one important multiresistant Staphylococcus aureus clinical isolate. It was found how the conjugation of diverse privileged substructure with embelin led to adducts having enhanced antibacterial activities.

Quinones as preventive agents in Alzheimer's diseases: focus on NLRP3 inflammasomes

OBJECTIVES

Alzheimer's disease (AD) is a hidden neurological degenerative disease, which main clinical manifestations are cognitive dysfunction, memory impairment and mental disorders. Neuroinflammation is considered as a basic response of the central nervous system. NLRP3 (Nucleotide-binding domain leucine-rich repeat (NLR) and pyrin domain containing receptor 3) inflammasome is closely related to the occurrence of neuroinflammation. Activation of the NLRP3 inflammasome results in the release of cytokines, pore formation and ultimately pyroptosis, which has demonstrated one of the critical roles in AD pathogenesis. Inhibition of the activity of NLRP3 is one of the focuses of the research. Therefore, NLRP3 represents an attractive pharmacological target, and discovery compounds with good NLRP3 inhibitory activity are particularly important.

KEY FINDINGS

Quinones have good neuroprotective effects and prevent AD, which may be related to their regulation of inflammatory response. The molecular docking was used to explore 12 quinones with AD prevention and treatment and NLRP3. Docking results showed that the combination of anthraquinones and NLRP3 were the best, and the top two chemical compounds were Purpurin and Rhein, which are the most promising NLRP3 inhibitors.

SUMMARY

These quinones may provide the theoretical basis for finding lead compounds for novel neuroprotective agents.