Naturally Occurring Carbazole Alkaloids from Murraya koenigii as Potential Antidiabetic Agents

Design, Synthesis, and Biological Evaluation of 1,4-Dihydropyridine-Indole as a Potential Antidiabetic Agent via GLUT4 Translocation Stimulation

In the quest for the discovery of antidiabetic compounds, a series of 27 1,4-dihydropyridine-indole derivatives were synthesized using a diversity approach. These compounds were systematically evaluated for their antidiabetic activity, starting with an in vitro assessment for GLUT4 translocation stimulation in L6-GLUT4myc myotubes, followed by in vivo antihyperglycemic activity evaluation in a streptozotocin (STZ)-induced diabetic rat model. Among the synthesized compounds, 12, 14, 15, 16, 19, 27, and 35 demonstrated significant potential to stimulate GLUT4 translocation in skeletal muscle cells. Compound 19 exhibited the highest potency and was selected for in vivo evaluation. A notable reduction of 21.6% (p < 0.01) in blood glucose levels was observed after 5 h of treatment with compound 19 in STZ-induced diabetic rats. Furthermore, pharmacokinetic studies affirmed that compound 19 was favorable to oral exposure with suitable pharmacological parameters. Overall, compound 19 emerged as a promising lead compound for further structural modification and optimization.

Sustainable strategies for using natural extracts in smart food packaging

The growing demand for sustainable and eco-friendly food packaging has prompted research on innovative solutions to environmental and consumer health issues. To enhance the properties of smart packaging, the incorporation of bioactive compounds derived from various natural sources has attracted considerable interest because of their functional properties, including antioxidant and antimicrobial effects. However, extracting these compounds from natural sources poses challenges because of their complex chemical structures and low concentrations. Traditional extraction methods are often environmentally harmful, expensive and time-consuming. Thus, green extraction techniques have emerged as promising alternatives, offering sustainable and eco-friendly approaches that minimise the use of hazardous solvents and reduce environmental impact. This review explores cutting-edge research on the green extraction of bioactive compounds and their incorporation into smart packaging systems in the last 10 years. Then, an overview of bioactive compounds, green extraction techniques, integrated techniques, green extraction solvents and their application in smart packaging was provided, and the impact of bioactive compounds incorporated in smart packaging on the shelf lives of food products was explored. Furthermore, it highlights the challenges and opportunities within this field and presents recommendations for future research, aiming to contribute to the advancement of sustainable and efficient smart packaging solutions.

Beneficial Effects of Natural Alkaloids from Berberis glaucocarpa as Antidiabetic Agents: An In Vitro, In Silico, and In Vivo Approach

Diabetes, also known as diabetes mellitus (DM), is a metabolic disorder characterized by an abnormal rise in blood sugar (glucose) levels brought on by a complete or partial lack of insulin secretion along with corresponding changes in the metabolism of lipids, proteins, and carbohydrates. It has been reported that medicinal plants play a pivotal role in the treatment of various ailments such as diabetes mellitus, dyslipidemia, and hypertension. The current study involved exploring the acute toxicity and in vivo antidiabetic activity of berberine (WA1), palmatine (WA2), and 8-trichloromethyl dihydroberberine (WA3) previously isolated from Berberis glaucocarpa Stapf using a streptozotocin (STZ)-induced diabetic rat model. Body weight and blood glucose level were assessed on a day interval for 4 weeks. Biochemical parameters, antioxidant enzymes, and oxidative stress markers were also determined. In an acute toxicity profile, the WA1, WA2, and WA3 were determined to be nontoxic up to 500 mg/kg (b.w). After the second and third weeks of treatment (14 and 21 days), the blood glucose levels in the WA1-, WA2-, and WA3-treated groups were significantly lower than those in the diabetic control group (476.81 ± 8.65 mg/dL, n = 8, P < 0.001). On the 21st day, there was a decrease in the blood glucose level and the results obtained were 176.33 ± 4.69, 197.21 ± 4.80, and 161.99 ± 4.75 mg/dL (n = 8, P < 0.001) for WA1, WA2, and WA3 at 12 mg/kg, respectively, as opposed to the diabetic control group (482.87 ± 7.11 mg/dL, n = 8, P < 0.001). Upon comparison with the diabetic group at the end of the study (28 days), a substantial drop in the glucose level of WA3 at 12 mg/kg (110.56 ± 4.11 mg/dL, n = 8, P < 0.001) was observed that was almost near the values of the normal control group. The treated groups (WA1, WA2, and WA3) treated with the samples displayed a significant decline in the levels of HbA1c. Treatment of the samples dramatically lowered the lipid level profile. In groups treated with samples, plasma levels of triglycerides, total cholesterol, and LDL were significantly lowered [F (5, 42) = 100.6, n = 8, P < 0.001]; these levels were also significantly decreased [F (5, 42) = 129.6 and 91.17, n = 8, P < 0.001]. In contrast to the diabetes group, all treated groups had significantly higher HDL levels [F (5, 42) = 15.46, n = 8, P < 0.001]. As a result, hypolipidemic activity was anticipated in the samples. In addition to that, the activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) was considerably elevated in the groups treated with the sample compared to the diabetic control group (n = 8, P < 0.001).

Substituent-controlled regioselective arylation of carbazoles using dual catalysis

Regioselective arylation of carbazoles is reported using dual palladium-photoredox catalysis. Controlled monoarylation and diarylation of symmetrical and unsymmetrical carbazoles were achieved under mild reaction conditions with a broad substrate scope and functional group tolerance. Steric and electronic control the regioselectivity of the arylation of unsymmetrical carbazoles. Late-stage functionalization of a caprofen drug derivative and large-scale synthesis of mono- and di-arylated carbazoles were demonstrated to showcase the synthetic versatility of the method. Finally, we also showcased the synthesis of hyellazole analogues (a marine alkaloid) in a short route using our strategy.

Site-selective synthesis and pharmacological elucidation of novel semi-synthetic analogues of koenimbine as a potential anti-inflammatory agent

Koenimbine (1), a carbazole alkaloid isolated from Murraya koenigii, belongs to the Rutaceae family. Various pharmacological effects such as anti-diabetic, melanogenesis inhibition, anti-diarrheal, anti-cancer, and anti-inflammatory properties of koenimbine have already been reported. In the current study, we investigated the anti-inflammatory role of koenimbine (1) and its novel semi-synthetic derivative 8-methoxy-3,3,5-trimethylpyrano[3,2-a] carbazole-11(3H)-yl) (3-(trifluoromethyl) phenyl) methanone (1G) in both in vitro and in vivo biological systems. Our results demonstrated that the anti-inflammatory activity of 1G significantly lowered the production of NO, pro-inflammatory cytokines (IL-6, TNF-α & IL-1β), LTB4 following LPS stimulation in RAW 264.7 macrophages. Furthermore, 1G significantly attenuated the expression levels of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in a dose dependent manner and also decreased the production of reactive oxygen species (ROS) in LPS-activated RAW 264.7 cells. In addition, the oral administration of 1G reduced the inflammatory response in carrageenan-induced paw edema in BALB/C mice. Moreover, it effectively reduced NO, IL-6, IL-1β & TNF-α levels, liver markers (AST, ALT), and kidney markers (BUN, CRE, and Urea). Also, 1G reverted the infiltration of inflammatory cells and tissue damage in lungs, liver and kidney enhanced the survival rate in LPS-challenged mice. 1G blocks NF-κB p65 from translocating into the nucleus and activating inflammatory gene transcription. These results illustrated that 1G suppresses the inflammatory effects both in-vitro and in-vivo studies via downregulating the nuclear factor kappa-B (NF-κB) signaling pathway. In conclusion, our results demonstrate that semi-synthetic derivative 1G can effectively attenuate the inflammatory response via NF-κB and MAPK signaling pathways; suggesting 1G is a potential novel anti-inflammatory drug candidate in treating inflammatory disorders.

Dual Palladium-Photoredox-Mediated Regioselective Acylation of Carbazoles and Indolines

We have described a dual palladium-photoredox-catalyzed highly regioselective acylation of carbazoles and indolines using molecular oxygen as the green oxidant. The reaction shows a broad substrate scope and good functional group tolerance. Late-stage functionalization of a carprofen drug derivative, further manipulation of products, and gram-scale synthesis of the acylated products were illustrated to show the versatility of the method.

C-H Bond Functionalization of N-Heteroarenes Mediated by Selectfluor

Herein, recent developments for Selectfluor-mediated C-H functionalization of N-heteroarenes are described. This type of C-H bond activation is an attractive and competitive alternative to traditional methodologies, allowing the functionalization of a variety of chemical functions. In addition, Selectfluor is a more sustainable and economically accessible oxidant compared with expensive/toxic metals or hazardous peroxides. For a practical understanding, the current review classified systematically the reported strategies in four subsections as follows: (1) carbon-carbon formation, (2) carbon-nitrogen bond formation, (3) carbon-chalcogen bond, and (4) carbon-halogen bond formation. Mechanistic aspects and reaction conditions are fully discussed to provide an understanding of the aspects that govern C-H functionalization in N-heteroarenes mediated by Selectfluor.

Design, synthesis, and evaluation of benzofuran-based chromenochalcones for antihyperglycemic and antidyslipidemic activities

A series of benzofuran-based chromenochalcones (16-35) were synthesized and evaluated for in vitro and in vivo antidiabetic activities in L-6 skeletal muscle cells and streptozotocin (STZ)-induced diabetic rat models, respectively, and further in vivo dyslipidemia activity of the compounds was evaluated in a Triton-induced hyperlipidemic hamster model. Among them, compounds 16, 18, 21, 22, 24, 31, and 35 showed significant glucose uptake stimulatory effects in skeletal muscle cells and were further evaluated for in vivo efficacy. Compounds 21, 22, and 24 showed a significant reduction in blood glucose levels in STZ-induced diabetic rats. Compounds 16, 20, 21, 24, 28, 29, 34, 35, and 36 were found active in antidyslipidemic studies. Furthermore, compound 24 effectively improved the postprandial and fasting blood glucose levels, oral glucose tolerance, serum lipid profile, serum insulin level, and the HOMA-index of db/db mice, following 15 days of successive treatment.

Furostanol saponins from Asparagus racemosus as potential hypoglycemic agents

Bioactivity guided phytochemical investigation led to isolation of six undescribed furostanol saponins, furoasparoside A-F along with five known compounds, gallic acid, methyl gallate, quercetin-3-O-β-glucopyranoside, liquiritigenin 4^׳-O-β-apiofuranosyl-(1 → 2)-β-glucopyranoside and β-glucogallin for the first time from the roots of Asparagus racemosus. Isolated saponins were screened for their antidiabetic potential in L6-GLUT4myc myotubes in vitro followed by an in vivo evaluation in streptozocin-induced diabetic rats and db/db mice. Furoasparoside E produced a notable decrease in the postprandial blood glucose profile, in leptin receptor-deficient db/db mice, type 2 diabetes model. The effect of furoasparoside E on GLUT4 translocation was found to be mediated by the AMPK-dependent signaling pathway in L6-GLUT4myc myotubes. Moreover, it emerged as a stable plant metabolite with higher bioavailability and efficacy in in vivo pharmacokinetic studies. Therefore, these studies indicated that furoasparoside E may serve as a propitious lead for the management of type 2 diabetes and its secondary complications from natural source.

Transition metal-catalyzed regioselective functionalization of carbazoles and indolines with maleimides

The directing group-assisted regioselective C-H activation of carbazoles and indolines is achieved via transition metal-catalyzed reactions. This C-H functionalization protocol provides a rapid approach to install diversely functionalized succinimide groups at the C-1 position of the carbazole moiety. In addition, this protocol demonstrates the intrinsic reactivity of indolines in providing C-2 succinimide-substituted indoles via cascade direct oxidation and C-H functionalization. This protocol also provides C-7 succinimide-substituted indolines under mild reaction conditions. The features of this reaction include a wide substrate scope and excellent regioselectivity for the installation of the succinimide moiety on biologically interesting molecules.

Phyto-Carbazole Alkaloids from the Rutaceae Family as Potential Protective Agents against Neurodegenerative Diseases

Plant-derived (phyto) carbazole alkaloids are an important class of compounds, presented in the family of Rutaceae (Genera Murraya, Clausena, Glycosmis, Micromelum and Zanthoxylum). Due to several significant biological activities, such as antitumor, antibacterial, antiviral, antidiabetic, anti-HIV and neuroprotective activities of the parent skeleton (3-methylcarbazole), carbazole alkaloids are recognized as an important class of potential therapeutic agents. Neurodegenerative diseases (NDs) may exhibit a vast range of conditions, affecting neurons primarily and leading ultimately to the progressive losses of normal motor and cognitive functions. The main pathophysiological indicators of NDs comprise increasing atypical protein folding, oxidative stresses, mitochondrial dysfunctions, deranged neurotransmissions and neuronal losses. Phyto-carbazole alkaloids can be investigated for exerting multitarget approaches to ameliorating NDs. This review presents a comprehensive evaluation of the available scientific literature on the neuroprotective mechanisms of phyto-carbazole alkaloids from the Rutaceae family in ameliorating NDs.

Nutritive Importance and Therapeutics Uses of Three Different Varieties (Murraya koenigii, Micromelum minutum, and Clausena indica) of Curry Leaves: An Updated Review

Murraya koenigii (M. koenigii), Micromelum minutum (M. minutum), and Clausena indica (C. indica) are three varieties of curry leaves in the family Rutaceae. They have been widely used in Ayurvedic medicine worldwide in the treatment and prevention of various diseases. Earlier findings provide strong evidence to support the three curry leaf species' potent pharmaceutical and biological effects, including antioxidant, antidiabetic, anti-inflammatory, and antitumor activities. Various parts of these plants, such as leaves, seeds, flowers, and fruit, contain constituents responsible for the modulation of numerous biological processes. Leading constituents of curry leaves play a crucial role in diabetic and anticancer management by regulating various molecular pathways, including Bcl-2, Bax, NF-κB, and TNFα, according to in vitro and in vivo models established. Therefore, this review summarizes the current knowledge on research achievements made in terms of phytoconstituents, their structures, biological activities, and pharmacological actions with clinical studies of curry leaves up to date. The review also emphasizes the necessity for comprehensive research studies on the pharmacological actions and the mechanisms of selected phytochemicals of M. koenigii, M. minutum, and C. indica to validate their efficacy as potent herbal remedies for many ailments.

Roles of Alkaloids from Medicinal Plants in the Management of Diabetes Mellitus

Medicinal plants play a fundamental part in health sectors via the management of different infectious diseases because of their wide plenitude wellspring of bioactive phytochemicals. Research activities on them have got attention throughout the world in the present days in search of low-cost and safe compounds for the management of diabetes. This is the literature-based analysis of alkaloids from medicinal plants in preventive or treatment approaches to diabetes. The most abundant and diversified group of secondary metabolites, i.e., alkaloids, show antidiabetic activity through the inhibition of enzymes (α-amylase, α-glucosidase, aldose reductase, dipeptidyl peptidase-IV, and protein tyrosine phosphatase-1B); inhibition of advanced glycation end products; increment of insulin secretion and its sensitivity; enhancement of glucose uptake; and their antioxidant ability. The study is useful for the examination of dynamic alkaloids for the advancement of a new medication for mankind.

Plants Secondary Metabolites as Blood Glucose-Lowering Molecules

Recently, significant advances in modern medicine and therapeutic agents have been achieved. However, the search for effective antidiabetic drugs is continuous and challenging. Over the past decades, there has been an increasing body of literature related to the effects of secondary metabolites from botanical sources on diabetes. Plants-derived metabolites including alkaloids, phenols, anthocyanins, flavonoids, stilbenoids, saponins, tannins, polysaccharides, coumarins, and terpenes can target cellular and molecular mechanisms involved in carbohydrate metabolism. In addition, they can grant protection to pancreatic beta cells from damage, repairing abnormal insulin signaling, minimizing oxidative stress and inflammation, activating AMP-activated protein kinase (AMPK), and inhibiting carbohydrate digestion and absorption. Studies have highlighted many bioactive naturally occurring plants' secondary metabolites as candidates against diabetes. This review summarizes the current knowledge compiled from the latest studies published during the past decade on the mechanism-based action of plants-derived secondary metabolites that can target various metabolic pathways in humans against diabetes. It is worth mentioning that the compiled data in this review will provide a guide for researchers in the field, to develop candidates into environment-friendly effective, yet safe antidiabetics.

Novel Phytochemical Constituents and their Potential to Manage Diabetes

BACKGROUND

Diabetes is a chronic disease affecting a large population worldwide and stands as one of the major global health challenges to be tackled. According to World Health Organization, about 400 million are having diabetes worldwide and it is the seventh leading cause of deaths in 2016. Plant-based natural products have been in use from ancient times as ethnomedicine for the treatment of several diseases, including diabetes. As a result of that, there are several reports on plant-based natural products displaying antidiabetic activity. In the current review, such antidiabetic potential compounds reported from all plant sources along with their chemical structures are collected, presented and discussed. These kinds of reports are essential to pool the available information to one source, followed by statistical analysis and screening to check the efficacy of all known compounds in a comparative sense. This kind of analysis can give rise to a few potential compounds from hundreds, which can further be screened through in vitro and in vivo studies, and human trails leading to the drug development.

METHODS

Phytochemicals, along with their potential antidiabetic property, were classified according to their basic chemical skeleton. The chemical structures of all the compounds with antidiabetic activities were elucidated in the present review. In addition to this, the distribution and their other remarkable pharmacological activities of each species are also included.

RESULTS

The scrutiny of literature led to the identification of 44 plants with antidiabetic compounds (70) and other pharmacological activities. For the sake of information, the distribution of each species in the world is given. Many plant derivatives may exert anti-diabetic properties by improving or mimicking insulin production or action. Different classes of compounds including sulfur compounds (1-4), alkaloids (5-11), phenolic compounds (12-17), tannins (18-23), phenylpropanoids (24-27), xanthanoids (28-31), amino acid (32), stilbenoid (33), benzofuran (34), coumarin (35), flavonoids (36-49) and terpenoids (50-70) were found to be potential active compounds for antidiabetic activity. Of the 70 listed compounds, majorly 17 compounds are obtained from triterpenoids, 13 from flavonoids and 7 from alkaloids. Among all the 44 plant species, the maximum number (7) of compounds were isolated from Lagerstroemia speciosa followed by Momordica charantia (6) and S. oblonga with 5 compounds.

CONCLUSION

This is the first paper to summarize the established chemical structures of phytochemicals that have been successfully screened for antidiabetic potential and their mechanisms of inhibition. The reported compounds could be considered as potential lead molecules for the treatment of type-2 diabetes. Further, molecular and clinical trials are required to select and establish therapeutic drug candidates.

Antidiabetic effect of Sophora pachycarpa seeds extract in streptozotocin-induced diabetic mice: a statistical evaluation

Undoubtedly, identification of the chemical composition of organic extracts or secondary metabolites of plant materials and evaluation of their potential bioactivity are among the main objectives of natural products-based investigations. In the present study, we report the chemical composition and antidiabetic activity of Sophora pachycarpa (Family Fabaceae) seeds extract (SPE) for the first time. First, the plant seeds were macerated in ethanol. The extract was subjected to analysis on a gas chromatography-mass spectrometry (GC-MS) system to identify the chemical composition. In vivo assay was run to evaluate the antidiabetic activity of the extract. Forty mice were divided into four groups, namely healthy mice, untreated diabetic mice, diabetic mice treated with metformin and diabetic mice treated with SPE. The antidiabetic activity of SPE was analyzed using three statistical methods, namely analysis of variance, K-means, and principal component analysis. According to GC-MS analysis, alkaloids of sophoridine, oleic acid, linoleic acid, and n-hexadecanoic acid were among the most abundant constituent components of SPE. The extract also exhibited a notable antidiabetic activity and remarkably decreased the levels of alkaline phosphatase (ALP), serum glutamic pyruvic transaminase (SGPT), and serum glutamic oxaloacetic transaminase (SGOT) enzymes. The statistical analyses revealed there are no significant differences between the ability of SPE and metformin in the regulation of fasting blood sugar level and liver enzymes (ALP, SGPT, and SGOT). A quinolizidine alkaloid, namely sophoridine, along with fatty acids, viz oleic, linoleic, and n-hexadecanoic acid, were characterized as the major compounds in S. tachycardia seeds extract. The plant extract was also found as a potent agent to reduce blood glucose and liver enzymes.

Semi-Synthesis of Small Molecules of Aminocarbazoles: Tumor Growth Inhibition and Potential Impact on p53

The tumor suppressor p53 is inactivated by mutation in approximately 50% of human cancers. Small molecules that bind and stabilize those mutants may represent effective anticancer drugs. Herein, we report the tumor cell growth inhibitory activity of carbazole alkaloids and amino derivatives, as well as their potential activation of p53. Twelve aminocarbazole alkaloids were semi-synthesized from heptaphylline (1), 7-methoxy heptaphylline (2), and 7-methoxymukonal (3), isolated from Clausena harmandiana, using a reductive amination protocol. Naturally-occurring carbazoles 1–3 and their amino derivatives were evaluated for their potential effect on wild-type and mutant p53 activity using a yeast screening assay and on human tumor cell lines. Naturally-occurring carbazoles 1–3 showed the most potent growth inhibitory effects on wild-type p53-expressing cells, being heptaphylline (1) the most promising in all the investigated cell lines. However, compound 1 also showed growth inhibition against non-tumor cells. Conversely, semi-synthetic aminocarbazole 1d showed an interesting growth inhibitory activity in tumor cells expressing both wild-type and mutant p53, exhibiting low growth inhibition on non-tumor cells. The yeast assay showed a potential reactivation of mutant p53 by heptaphylline derivatives, including compound 1d. The results obtained indicate that carbazole alkaloids may represent a promising starting point to search for new mutp53-reactivating agents with promising applications in cancer therapy.

Synthesis and biological evaluation of pyranocarbazole derivatives as Anti-tumor agents

A series of pyrano[3,2-a]carbazole alkaloids were designed and synthesized as derivatives of Girinimbine. The anticancer activities of these derivatives (3, 4a-j, 5a, 5c, 5f, 5i, 6c, 7a, 7c, 7f, 7i) against 10 cancer cell lines were studied. Among them, compounds 3 and 7i with N-methyl piperazine showed significant anticancer activity against MCF-7 cell lines with the IC50 values of 1.77 and 4.32 μM, respectively. Furthermore, their effects on altering cell morphology, inducing cell cycle arrest and apoptosis in MCF-7 cells were studied in vitro. In addition, the molecular docking study was carried out by using Discovery Studio software to predict the interactions between these derivatives and tubulin. All in all, these consequences reveal that pyranocarbazole derivatives with N-methyl piperazine can be used as potential anticancer lead compounds and provide useful points for the further optimization of pyranocarbazole alkaloids.

Antimalarial application of quinones: A recent update

Atovaquone belongs to a naphthoquinone class of drugs and is used in combination with proguanil (Malarone) for the treatment of acute, uncomplicated malaria caused by Plasmodium falciparum (including chloroquine-resistant P. falciparum/P. vivax). Numerous quinone-derived compounds have attracted considerable attention in the last few decades due to their potential in antimalarial drug discovery. Several semi-synthetic derivatives of natural quinones, synthetic quinones (naphtho-/benzo-quinone, anthraquinones, thiazinoquinones), and quinone-based hybrids were explored for their in vitro and in vivo antimalarial activities. A careful literature survey revealed that this topic has not been compiled as a review article so far. Therefore, we herein summarise the recent discovery (the year 2009-2020) of quinone based antimalarial compounds in chronological order. This compilation would be very useful towards the exploration of novel quinone-derived compounds against malarial parasites with promising efficacy and lesser side effects.

Metronidazole-conjugates: A comprehensive review of recent developments towards synthesis and medicinal perspective

Nitroimidazoles based compounds remain a hot topic of research in medicinal chemistry due to their numerous biological activities. Moreover, many clinical candidates based on this chemical core have been reported to be valuable in the treatment of human diseases. Metronidazole (MTZ) derived conjugates demonstrated a potential application in medicinal chemistry research over the last decade. In this review, we summarize the synthesis, key structure-activity-relationship (SAR) and associated biological activities such as antimicrobial, anticancer, antidiabetic, anti-inflammatory, anti-HIV and anti-parasitic (Anti-trichomonas, antileishmanial, antiamoebic and anti-giardial) of explored MTZ-conjugates. The molecular docking analysis is also presented simultaneously, which will assist in developing an understanding towards designing of new MTZ-conjugates for target-based drug discovery against multiple disease areas.

Nitric Oxide Inhibitory Carbazole Alkaloids from the Folk Medicine Murraya tetramera C.C. Huang

The phytochemical investigation of the leaves and stems of Murraya tetramera C.C. Huang, a traditional folk medicine used as an anti-inflammatory agent, yielded 19 simple carbazole alkaloids, two of which (1-ethoxy-3-methyl-9H-carbazol-2-ol (1) and 7-hydroxy-2,8-dimethoxy-6-methyl-9H-carbazole-1-carbaldehyde (2)) are new ones. The structures of the new compounds were determined by extensive spectroscopic analysis including NMR and HR-EI-MS experiments, as well as comparison with the reported data. Most of the isolates showed potent inhibitory effects on NO production in LPS-stimulated BV-2 microglial cells with IC₅₀ values ranging from 5.1 to 15.1 μM.

Medicinal Profile, Phytochemistry, and Pharmacological Activities of Murraya koenigii and its Primary Bioactive Compounds

The discovery of several revitalizing molecules that can stop or reduce the pathology of a wide range of diseases will be considered a major breakthrough of the present time. Available synthetic compounds may provoke side effects and health issues, which heightens the need for molecules from plants and other natural resources under discovery as potential methods of replacing synthetic compounds. In traditional medicinal therapies, several plant extracts and phytochemicals have been reported to impart remedial effects as better alternatives. Murraya koenigii (M. koenigii) belongs to the Rutaceae family, which is commonly used as a medicinally important herb of Indian origin in the Ayurvedic system of medicine. Previous reports have demonstrated that the leaves, roots, and bark of this plant are rich sources of carbazole alkaloids, which produce potent biological activities and pharmacological effects. These include antioxidant, antidiabetic, anti-inflammatory, antitumor, and neuroprotective activities. The present review provides insight into the major components of M. koenigii and their pharmacological activities against different pathological conditions. The review also emphasizes the need for more research on the molecular basis of such activity in various cellular and animal models to validate the efficacy of M. koenigii and its derivatives as potent therapeutic agents.

Design, Synthesis and In Vitro Characterization of Novel Antimicrobial Agents Based on 6-Chloro-9H-carbazol Derivatives and 1,3,4-Oxadiazole Scaffolds

In this paper, we aimed to exploit and combine in the same molecule the carbazole and the 1,3,4-oxadiazole pharmacophores, to obtain novel carprofen derivatives, by using two synthesis pathways. For the first route, the following steps have been followed: (i) (RS)-2-(6-chloro-9H-carbazol-2-yl)propanonic acid (carprofen) treatment with methanol, yielding methyl (RS)-2-(6-chloro-9H-carbazol-2-yl)propanoate; (ii) the resulted methylic ester was converted to (RS)-2-(6-chloro-9H-carbazol-2-yl)propane hydrazide (carprofen hydrazide) by treatment with hydrazine hydrate; (iii) reaction of the hydrazide derivative with acyl chlorides led to N-[(2RS)-2-(6-chloro-9H-carbazol-2-yl)propanoil]-N′-R-substituted-benzoylhydrazine formation, which; (iv) in reaction with phosphorus oxychloride gave the (RS)-1-(6-chloro-9H-carbazol-2-yl)-1-(1,3,4-oxadiazol-2-yl)ethane derivatives. In the second synthesis pathway, new 1,3,4-oxadiazole ring compounds were obtained starting from carprofen which was reacted with isoniazid, in the presence of phosphorus oxychloride to form (RS)-1-(6-chloro-9H-carbazol-2-yl)-1-[5-(4-pyridyl)-1,3,4-oxadiazol-2-yl]ethane. The synthesized compounds were characterized by IR, ¹H-NMR and ¹³C-NMR, screened for their drug-like properties and evaluated for in vitro cytotoxicity and antimicrobial activity. The obtained compounds exhibited a good antimicrobial activity, some of the compounds being particularly active on E. coli, while others on C. albicans. The most significant result is represented by their exceptional anti-biofilm activity, particularly against the P. aeruginosa biofilm. The cytotoxicity assay revealed that at concentrations lower than 100 μg/mL, the tested compounds do not induce cytotoxicity and do not alter the mammalian cell cycle. The new synthesized compounds show good drug-like properties. The ADME-Tox profiles indicate a good oral absorption and average permeability through the blood brain barrier. However, further research is needed to reduce the predicted mutagenic potential and the hepatotoxicity.

Identification of Racemic and Chiral Carbazole Derivatives Containing an Isopropanolamine Linker as Prospective Surrogates against Plant Pathogenic Bacteria: In Vitro and In Vivo Assays and Quantitative Proteomics

Recent observations on the emergence of drug-resistant plant pathogenic bacteria have highlighted and elicited an acute campaign to develop novel, highly efficient antibiotic surrogates for managing bacterial diseases in agriculture. Thus, a type of racemic and chiral carbazole derivative containing an isopropanolamine pattern was systematically synthesized to discover low-cost and efficient antibacterial candidates. Screening results showed that compounds 2f, 6c, and 2j could significantly suppress the growth of tested plant pathogens, namely Xanthomonas oryzae pv oryzae, X. axonopodis pv citri, and Pseudomonas syringae pv actinidiae, and provided the corresponding EC₅₀ values of 1.27, 0.993, and 0.603 μg/mL, which were significantly better than those of existing commercial drugs. In vivo studies confirmed their prospective applications for controlling plant bacterial diseases. Label-free quantitative proteomics analysis indicated that compound 2f could dramatically induce the up- and down-regulation of a total of 247 differentially expressed proteins, which was further validated by the parallel reaction monitoring technique. Moreover, fluorescence spectra and SEM images were obtained to further explore the antibacterial mechanism.

Antihyperglycemic Activity of Murraya koenigii Leaves Extract on Blood Sugar Level in Streptozotocin-Nicotinamide Induced Diabetes in Rats

The effects of Murraya koenigii leaves are very less studied in streptozotocin-nicotinamide (STZ-NA) induced diabetes rat model, in spite of several studies reported its antidiabetic effects in alloxan and STZ induced diabetes. The present study was undertaken to assess the effects of Murraya koenigii leaves extract on the blood sugar level (BSL) of STZ-NA diabetic rats. Experimental diabetes was induced by STZ injection intraperitoneally (i. p) after 30 min of NA injection i. p in all groups apart from normal control group. Group I (normal control) and Group II (diabetic control) rats received distilled water. Group III rats treated Metformin, Group IV and Group V rats treated Murraya koenigii aqueous extract and Murraya koenigii methanolic extract respectively. BSL and body weights of rats were measured at each week of the period of 28 days. Our results indicate that oral administration of Murraya koenigii reduces BSL significantly compared with the diabetic group. No weight loss was observed in all groups. The findings of the present study suggest that Murraya koenigii is proven as anti-diabetic agent in diabetic rats.

Aplysinopsin-type and Bromotyrosine-derived Alkaloids from the South China Sea Sponge Fascaplysinopsis reticulata

Seven pairs of new oxygenated aplysinopsin-type enantiomers, (+)- and (-)-oxoaplysinopsins A‒G (1‒7), two new bromotyrosine-derived alkaloids, subereamollines C and D (18 and 19), together with ten known compounds (8‒17) were isolated from the Xisha Islands sponge Fascaplysinopsis reticulata. The planar structures were determined by extensive NMR and MS spectroscopic data. Each of the optically pure enantiomers was achieved by chiral HPLC separation. The absolute configurations were assigned by the quantum chemical calculation methods. Compound 19 showed cytotoxicity against Jurkat cell lines with IC₅₀ value of 0.88 μM. Compounds 2, 16 and 17 showed tyrosine phosphatase 1B (PTP1B) inhibition activity with IC₅₀ value ranging from 7.67 to 26.5 μM, stronger than the positive control of acarbose and 1-deoxynojirimycin. A structural activity relationship for the aplysinopsin-type enantiomers were observed in PTP1B inhibition activity of 2 and cytotoxicity of 3 that the dextrorotary (+)-2 and (+)-3 showed stronger activity than the levorotary (-)-2 and (-)-3.

Role of medicinal plants in the management of diabetes mellitus: a review

Medicinal plants have a vast potential in the treatment of various ailments due to the presence of therapeutically important phytochemicals. Diabetes is a serious metabolic disorder and several marketed medications are available to alleviate the symptoms of diabetes. However, these over the counter drugs are expensive and associated with several complications. Herbal medicines are gaining importance as they are cost-effective and also display improved therapeutic effects with lesser side effects. The present review includes the reports available on medicinal plants used for treating diabetes complications. The aim of the review is to categorize and summarize the available information on medicinal plants with anti-diabetic properties and suggesting outlooks for future research. A systematic search was performed on medicinal plants with anti-diabetic properties using several search engines such as Google Scholar, PubMed, Science Direct and other online journals and books. All the plants listed in this review are native to Asian countries and are routinely used by the traditional practitioners for the treatment of various ailments. Based on the literature data available, a total of 81 medicinal plants with anti-diabetic, anti-hyperglycemic, hypoglycemic, anti-lipidemic and insulin mimetic properties have been compiled in this review. This review provides useful information about the different medicinal plants for treating diabetes-associated complications. Further research can be carried out to study the active constituents and mechanism of these plants.

Anti-colon cancer activity of Murraya koenigii leaves is due to constituent murrayazoline and O-methylmurrayamine A induced mTOR/AKT downregulation and mitochondrial apoptosis

In recent years, many alkaloids of plant origin have attracted great attention due to their diverse range of biological properties including anti-hyperglycemic, anti-oxidant, anti-inflammatory, anti-diabetic and anti-tumor activity. Herein, the pyranocarbazole alkaloids were isolated from leaves of Murraya koenigii and their anti-cancer potential was investigated in different cancer cell lines. Among all tested compounds, murrayazoline and O-methylmurrayamine A demonstrated potent anti-cancer activity against DLD-1 colon cancer cells with the IC₅₀ values of 5.7μM and 17.9μM, respectively, without any non-specific cytotoxicity against non-cancer HEK-293 and HaCaT cells. Further, studies of pure compounds revealed that the anti-cancer activity of compounds corresponds with altered cellular morphology, cell cycle arrest in G2/M phase, reactive oxygen species level and mitochondrial membrane depolarization of colon cancer cells. In addition, these compounds activated caspase-3 protein and upregulated Bax/Bcl-2 protein expression ratio leading to induction of caspase-dependent apoptosis in DLD-1 cells. These event induced by carbazole alkaloids also coincides with downregulation of Akt/mTOR suggesting downstream targeting of cell survival pathway. Thus, our in vitro studies not only provided scientific basis of the use of M. koenigii leaves in the traditional Indian Ayurveda medicines, but also expands possibilities of medicinal uses of M. koenigii leaves against colon cancer. Particularly, these findings will help in further investigating murrayazoline and O-methylmurrayamine A or their improvised derivatives as new therapeutics for the treatment of colon cancer.

Total synthesis and neuroprotective effect of O-methylmurrayamine A and 7-methoxymurrayacine

O-Methylmurrayamine A (7) and 7-methoxymurrayacine (8) are natural products isolated from Murraya koenigii and Murraya siamensis, respectively. In this paper, we report the synthesis of 7 and 8 which are featured in the key step of cyclization to form carbazole intermediate 5 with mild conditions. The structures were confirmed by ¹H NMR, ¹³C NMR, and HR-ESI-MS. In addition, compounds 7 and 8 were tested for their neuroprotective effects against H₂O₂-induced PC12 cell damage. The results showed that compounds 7 and 8 have neuroprotective effect.

Methodology and applications of the hexadehydro-Diels–Alder (HDDA) reaction

Hexadehydro-Diels–Alder (HDDA) reactions between alkynes and 1,3-diynes readily generate highly reactive and synthetically useful arynes.

Hexadehydro-Diels-Alder (HDDA)-Enabled Carbazolyne Chemistry: Single Step, de Novo Construction of the Pyranocarbazole Core of Alkaloids of the Murraya koenigii (Curry Tree) Family

Here we report the use of the hexadehydro-Diels-Alder (HDDA) reaction for the de novo construction of a benzenoid ring in fused polycyclic heteroaromatic carbazole (i.e., [2,3]-benzoindole) skeletons. The strategy allows creation of highly substituted benzenoids. We also describe the HDDA-enabled chemical synthesis of the natural product alkaloids mahanimbine and koenidine. Trapping of the intermediate carbazolyne with a conjugated enal, proceeding through formal [2+2] cycloaddition, 4π-electrocyclic ring opening, and 6π-electrocyclic ring-closing events, constitutes a robust method for producing pyranocarbazoles.