Antibacterial activity of Clausena heptaphylla

Use of stability statistics in the selection of Clausena heptaphylla (Roxb.) Wight & Arn for novel anethole rich strain (Jor Lab CH-2)

INTRODUCTION

Anethole is an industrially important compound which is extensively used in pharmaceuticals, cosmetics, perfumery, food and confectioneries. Anethole is primarily obtained from fennel, anise, and star anise which is highly expensive. Therefore, a study was performed to identify a cost-effective and natural anethole rich strain of Clausena heptaphylla through selection and confirmed through multilocation trial.

METHODS

The study was conducted using 23 accessions collected from North eastern region of India from 2014-2018 (initial evaluation trial) and 2018-2022 (multilocation trial). The initial trial was conducted in the experimental farm of CSIR-NEIST, Jorhat, Assam using Complete Randomized Block Design with three replications. Five agronomical traits (plant height, leaf length, leaf width, number of stem branching, herbage yield per plant per cutting) along with essential oil yield and anethole content were evaluated which led to the identification of anethole rich strain of C. heptaphylla. This identified strain was further evaluated along with the two check genotypes for stability based on three yield parameters viz. herbage yield, essential oil yield and anethole content at four multi-locations (Imphal, Jorhat, Runne and Madang) for four years using the same experimental design.

RESULTS AND DISCUSSION

The identified superior line (Jor Lab CH-2) showed consistent performance for the studied yield parameters across all the environments maintaining its superiority. The identified strain exhibited average herbage yield of 1.2 Kg/plant/cutting and essential oil yield of 1.22%. The GC-MS analysis of the essential oil depicted trans anethole as the major constituent (93.25%) followed by estragole (4.85%) while benzene, 1,2-dimethoxy-4-(1-propenyl Isoeugenol methyl ether and cis-anethole were the trace components. This is the first novel report of anethole rich variant of C. heptaphylla which has undergone multilocational trial over the years. Jor Lab CH-2 strain will open a new scope for the industries to isolate anethole from a different source in a cost-effective approach.

The Journey of 1-Keto-1,2,3,4-Tetrahydrocarbazole Based Fluorophores: From Inception to Implementation

Carbazole is a unique template associated with several biological activities. It is due to the diverse and versatile biological properties of carbazole derivatives that they are of immense interest to the research community. 1-keto-1,2,3,4-tetrahydrocarbazoles are important synthetic intermediates to obtain carbazole derivatives. Several members of this family emit fluorescence on photoexcitation. In the context of biochemical and biophysical research, designing and characterising small molecule environment sensitive fluorophores is extremely significant. This article aims to be a state of the art review with synthetic and photophysical details of a variety of fluorophores based on 1-keto-1,2,3,4-tetrahydrocarbazole skeleton.

Antimicrobial activities of the extracts and secondary metabolites from Clausena genus – A review

Antimicrobial drug resistance has become a global challenge and one of utmost concern due to the global epidemiological infections. Medicinal plants have long performed an essential role in medicine and can be an essential source of recent antimicrobials and techniques for treating resistance. Clausena is a genus in the Rutaceae family which are widely recognized and utilized in traditional medicines. Many members of this genus have been a primary source of medications and drug history. The antimicrobial effectiveness of the secondary metabolites from the roots, stems, leaves, rhizomes, twigs, seeds, fruits, and flowers of several Clausena species has been widely examined and was found to be more effective against bacteria with Clausena anisata being the most promising specie. A total of 16 active compounds including 12 alkaloids, 2 coumarins, and 2 terpenoids were reported to be isolated from different parts of the plant species with mukonal being the only compound that shows dual potency both against fungi and protozoa. This review aims to sum up research advances made from 2000 to date, on the antibacterial, antifungal, and antiprotozoal activities of Clausena species, and highlight the potential use of Clausena plants in the prevention and treatment of infectious diseases.

Anethole rich Clausena heptaphylla (Roxb.) Wight & Arn., essential oil pharmacology and genotoxic efficiencies

Anethole, a widely used industrial flavoring agent is majorly sourced from anise and star anise. The present study is aimed to the in-depth pharmacological analysis i.e. anti-diabetic, skin whitening, neurodegenerative disorder inhibitory activities of anethole-rich Clausena heptaphylla leaf essential oil (ARCHEO) (88.59%) as revealed by the Gas Chromatography/Mass Spectrometry (GC/MS) analysis and further confirmed by proton nuclear magnetic resonance ¹H-NMR as well as to compare with standard compound anethole. ARCHEO (ABTS EC₅₀ 6.97 ± 0.004 µg/mL; Protease assay 4.51 ± 0.004 µg/mL) outperformed the standard compound anethole (ABTS EC₅₀ 9.48 ± 0.048 µg/mL; Protease assay EC₅₀ 22.64 ± 0.016 µg/mL) in antioxidant and anti-inflammatory experiments. ARCHEO was also shown to be more effective than the reference compound anethole in terms of anti-diabetic activity (EC₅₀ 22.35 ± 0.121 µg/mL), tyrosinase inhibitory activity (EC₅₀ 16.45 ± 0.012 µg/mL), and anti-cholinesterase activity (EC₅₀ 22.32 ± 0.016 µg/mL). However, ARCHEO exhibited lower antimicrobial activity towards all the tested microbes compared to standard compound anethole and as for the MIC, ARCHEO was effective only towards Salmonella typhimurium (60 µg/mL), Streptococcus mutans (20 µg/mL), and Aspergillus fumigatus (75 µg/mL). ARCHEO (11.11%) and anethole (12.33%) showed no genotoxic effect based on Allium cepa assay mitotic index value. Thus, ARCHEO could be a commercially viable and widely available cheaper source of anethole, which has buoyant demand in the field of food flavoring, fragrance, and pharmaceutical industries.

Convenient One-Pot Synthesis of 9H-Carbazoles by Microwave Irradiation Employing a Green Palladium-Based Nanocatalyst

An efficient palladium-catalyzed tandem reaction for the one-pot synthesis of 9H-carbazoles under microwave irradiation is developed. This approach involves a sequential Buchwald–Hartwig amination and a direct arylation from affordable and inexpensive anilines and 1,2-dihaloarenes. For the development of this purpose, a novel and magnetically recoverable palladium nanocatalyst supported on a green biochar under ligand-free conditions is used. Compared to other existing palladium-based protocols, the present synthetic methodology shows a drastic reduction in reaction times and excellent compatibility with different functional groups allowing to obtain a small library of 9H-carbazoles in high yields and with good regioselectivity. This procedure represents the first example in the direct synthesis of carbazoles using a heterogeneous palladium nanocatalyst from commercial precursors. To examine the application of this protocol, a direct and scalable synthesis of the bioactive carbazole alkaloid clausenalene from commercially available starting materials is described.

Monitoring the Competence of a New Keto-tetrahydrocarbazole Based Fluorosensor Under Homogeneous, Micro-Heterogeneous and Serum Albumin Environments

We present here a detailed photophysical study of a recently synthesised fluorophore 8-methyl-8,9-dihydro-5H-[1,3]dioxolo[4,5-b]carbazol-6(7H)-one. This is a synthetic precursor of bio-active carbazole skeleton Clausenalene. Spectroscopic investigation of the fluorophore has been carried out in different protic and aprotic solvents, as well as in binary solvent mixtures, using absorption, steady-state and time-resolved fluorescence techniques. This fluorophore is particularly responsive to the hydrogen bonding nature as well as polarity of the solvent molecules. When considered in micelles and β-cyclodextrin, this behaves as a reporter of its immediate microenvironment. Steady state and time resolved fluorometric and circular dichroism techniques have been used to explore the binding interaction of the fluorophore with transport proteins, bovine serum albumin and human serum albumin. The probable binding sites of the fluorophore in the proteinous environments have been evaluated from fluorescence resonance energy transfer study. Laser flash photolysis experiments also have been performed to observe the triplet excited state interaction between the fluorophore and albumin proteins.

Simultaneous determination of nine analytes in Clausena harmandiana Pierre. by new developed high-performance liquid chromatography method and the influence of locations in Thailand on level of nordentatin and dentatin

Background:

Clausena harmandiana Pierre. (CH) contains various bioactive analytes with pharmacological benefits. Most researches were focused on carbazole analytes determined by isocratic high-performance liquid chromatography (HPLC), only few were focused on coumarin analytes and harvested location.

Objective:

To develop and validate gradient HPLC method to analyze the variance of nine target analytes contained in roots of CH grown naturally in four different provinces of Thailand.

Materials and Methods:

The analytical method was undertaken by gradient HPLC with 3% tetrahydrofuran in acetonitrile, and 0.05% phosphoric acid in water as mobile phases, on Hypersil ODS column (4.0 × 250 mm, 5 μm), at flow rate 1.0 mL/min and detected at wavelength 280 nm. The method was validated for system linearity, limit of detection, limit of quantitation, precision and accuracy.

Results:

The new-developed method was able to detect the nine target analytes in CH root. The validation showed the reliability of the method. All system suitability parameters were within the satisfied limits. The linear responses of method were observed at r² ≥ 0.999 for all analytes. The obtained amount of nine analytes showed the biodiversity of contents in different provinces. Of the nine target analytes, the level of nordentatin and dentatin in coumarin groups were considerably high in plants collected from one specific province of Thailand.

Conclusion:

This study has shown that the new-developed method is reliable, precise, accurate and sensitive to determine and quantify the nine target analytes in CH. Nordentatin and dentatin obviously show the higher level in one specific province of Thailand.

Antibacterial, antifungal and antioxidant activities of the ethanol extract of the stem bark of Clausena heptaphylla

Background

There is wide spread interest in drugs derived from plants as green medicine is believed to be safe and dependable, compared with costly synthetic drugs that have adverse effects.

Methods

We have attempted to evaluate the antioxidant, In vitro thrombolytic, antibacterial, antifungal and cytotoxic effects of Clausena heptaphylla (Rutaceae) stem bark extract ethanol extract.

Results

Ethanolic stem bark extract of Clausena heptaphylla (CHET) contains flavonoids, alkaloids, saponins and steroids but it lacks tannins, anthraquinones and resins. Phenol content of the extract was 13.42 mg/g and flavonoid content was 68.9 mg/g. CHET exhibited significant DPPH free radical scavenging activity with IC₅₀ value of 3.11 μg/ml. Reducing power of CHET was also moderately stronger. In the cytotoxicity assay, LC₅₀ and Chi-square value of the ethanolic extract against brine shrimp nauplii were 144.1461 μg/ml and 0.8533 demonstrating potent cytotoxic effect of the extract. In vitro thrombolytic activity of CHET is significant with 45.38% clot lysis capability compared to that of Streptokinase (65.78%). In antibacterial screening, moderate zone of inhibition (6.5-9.0 mm in diameter) was observed against gram-positive Bacillus subtilis ATCC 11774, Bacillus cereus ATCC 10876, Staphylococcus aureus ATCC 25923, Bacillus polymyxa ATCC 842 and Bacillus megaterium ATCC 13578 and less promising zone of inhibition (3.0-4.5 mm in diameter) against gram-negative Salmonella typhi ATCC 65154, Shigella flexneri ATCC 12022, Proteus vulgaris ATCC 13315 and Escherichia coli ATCC 25922. Shigella sonnei ATCC 8992 did not show any sensitivity. The MIC values against these bacteria were ranged from 2,000 to 3,500 μg/ml. The extract showed significant zone of inhibition against Rhizopus oryzae DSM 2200, Aspergillus niger DSM 737 and Aspergillus ochraceus DSM 824 in antifungal assay.

Conclusions

Further advanced research is necessary to isolate and characterize the chemical components responsible for the therapeutic properties of the plant.