Identification of alkaloids from Justicia adhatoda as potent SARS CoV-2 main protease inhibitors: An in silico perspective.

The COVID-19 pandemic, caused by SARS CoV-2, is responsible for millions of death worldwide. No approved/proper therapeutics is currently available which can effectively combat this outbreak. Several attempts have been undertaken in the search of effective drugs to control the spread of SARS CoV-2 infection. The main protease (Mpro), key component for the cleavage of the viral polyprotein, is considered to be one of the important drug targets for treating COVID-19. Various phytochemicals, including polyphenols and alkaloids, have been proposed as potent inhibitors of Mpro. The alkaloids from leaf extracts of Justicia adhatoda have also been reported to possess anti-viral activity. But whether these alkaloids exhibit any inhibitory effect on SARS CoV-2 Mpro is far from clear. To explore this in detail, we have adopted computational approaches. Justicia adhatoda alkaloids possessing proper drug-likeness properties and two anti-HIV drugs (lopinavir and darunavir; having binding affinity -7.3 to -7.4 kcal/mol) were docked against SARS CoV-2 Mpro to study their binding properties. Only one alkaloid (anisotine) had interaction with both the catalytic residues (His41 and Cys145) of Mpro and exhibited good binding affinity (-7.9 kcal/mol). Molecular dynamic simulations (100 ns) revealed that Mpro-anisotine complex is more stable, conformationally less fluctuated; slightly less compact and marginally expanded than Mpro-darunavir/lopinavir complex. Even the number of intermolecular H-bonds and MM-GBSA analysis suggested that anisotine is a more potent Mpro inhibitor than the two previously recommended antiviral drugs (lopinavir and darunavir) and may evolve as a promising anti-COVID-19 drug if proven in animal experiments and on patients.

Simultaneous determination of pyrroquinazoline alkaloids and flavonoids in Adhatoda beddomei and Adhatoda vasica and their marketed herbal formulations using ultra-high-performance liquid chromatography coupled with triple quadrupole linear ion trap mass spectrometry.

Adhatoda beddomei and Adhatoda vasica leaf, known as 'Vasaka' and/or 'Vasa' in Ayurveda and 'Malabar nut' in English, is an official drug in the Indian Pharmacopoeia. The medicinal properties of these plants are due to the presence of pyrroquinazoline alkaloids. An UHPLC-ESI/MS/MS method in both positive and negative electrospray ionization in multiple-reaction-monitoring mode was developed and validated for the estimation of alkaloids and flavonoids in Adhatoda species and their marketed herbal formulations. Chromatographic separation was achieved on an Acquity UPLC® BEH C18 -column using a gradient elution with 0.1% formic acid in water and methanol. The developed method was validated as per International Conference on Harmonization guidelines and found to be accurate with overall recovery in the range 94.2-105.0% (RSD ≤ 1.71%), precise (RSD ≤ 3.44%) and linear (R2 ≥ 0.9992) over the concentration range of 0.5-1000 ng/mL. The total content of alkaloids and flavonoids were highest in the chloroform and aqueous fraction of A. vasica leaf, respectively. The results indicated that the developed method was simple, rapid, sensitive, selective and accurate for the estimation of multiple bioactive constituents in crude mixture, and therefore could make a contribution to the quality control of Adhatoda species and its derived herbal formulations.

Antibacterial Activity of Green Synthesized Silver Nanoparticles Using Vasaka (Justicia adhatoda L.) Leaf Extract.

There is an increasing demand for silver nanoparticles due to its wide applicability in various area of biological science such as in field of antimicrobial and therapeutics, biosensing, drug delivery etc. To use in bioprocess the silver nanoparticles should be biocompatible and free from toxic chemicals. In the present study we report a cost effective and environment friendly route for green synthesis of silver nanoparticles using Vasaka (Justicia adhatoda L.) leaf extract as reducing as well as capping agent. This plant has been opted for the present study for its known medicinal properties and it is easily available. The biosynthesized silver nanoparticles are characterized by UV-Vis spectroscopy and TEM analysis. It is observed the nanoparticles are well shaped and the average particle size is 20 nm in the range of 5-50 nm. The antibacterial activity of these nanoparticles against Pseudomonas aeruginosa MTCC 741 has been measured by disc diffusion method, agar cup assay and serial dilution turbidity measurement assay. The results show green synthesized silver nanoparticles, using Vasaka leaf extract, have a potential to inhibit the growth of bacteria.

Exploring the pharmacological and chemical aspects of pyrrolo-quinazoline derivatives in Adhatoda vasica.

Adhatoda or Justicia is one of the biggest and complex genera of the Acanthaceae family. Adhatoda vasica is commonly known as 'Adosa'. It is an ayurvedic medicine with a medicinal history of more than a thousand years in India. Traditionally, it is used to treat cough, asthma, phlegm, bleeding hemorrhoids, for both adults and youth. This plant possesses antiarthritis, antiseptic, antimicrobial, anti-tuberculosis, anti-inflammatory and abortifacient properties. Alkaloids are the major phytoconstituents present in the plant in the form of pyrrolo-quinazoline derivatives viz vasicine, vasicinone, vasicinol, adhatodine, adhatodinine, adhavasinone and anisotine etc. The asserted objectives are to conduct a systematic review on the phytochemistry, pharmacology and traditional uses of A. vasica, as well as highlighting the challenges found in the research. This will promote the utilization of A. vasica at extract level and further development of new drug leads based on the compounds isolated and used for treatment of various ailments. The present review covers the literature survey from 1888 to 2023. The relevant data has been collected from various peer-reviwed journals, and books via Sci-Finder, PubMed, Science Direct, Google Scholar, EBSCO, online electronic journals, SpringerLink and Wiley. This paper aims to present a systematic review of known traditional applications, pharmacological and chemical aspects in Adhatoda vasica.

Inhibition of TRPA1, Endoplasmic Reticulum Stress, Human Airway Epithelial Cell Damage, and Ectopic MUC5AC Expression by Vasaka (Adhatoda vasica; Malabar Nut) Tea.

This study tested whether a medicinal plant, Vasaka, typically consumed as a tea to treat respiratory malaise, could protect airway epithelial cells (AECs) from wood smoke particle-induced damage and prevent pathological mucus production. Wood/biomass smoke is a pneumotoxic air pollutant. Mucus normally protects the airways, but excessive production can obstruct airflow and cause respiratory distress. Vasaka tea pre- and co-treatment dose-dependently inhibited mucin 5AC (MUC5AC) mRNA induction by AECs treated with wood smoke particles. This correlated with transient receptor potential ankyrin-1 (TRPA1) inhibition, an attenuation of endoplasmic reticulum (ER) stress, and AEC damage/death. Induction of mRNA for anterior gradient 2, an ER chaperone/disulfide isomerase required for MUC5AC production, and TRP vanilloid-3, a gene that suppresses ER stress and wood smoke particle-induced cell death, was also attenuated. Variable inhibition of TRPA1, ER stress, and MUC5AC mRNA induction was observed using selected chemicals identified in Vasaka tea including vasicine, vasicinone, apigenin, vitexin, isovitexin, isoorientin, 9-oxoODE, and 9,10-EpOME. Apigenin and 9,10-EpOME were the most cytoprotective and mucosuppressive. Cytochrome P450 1A1 (CYP1A1) mRNA was also induced by Vasaka tea and wood smoke particles. Inhibition of CYP1A1 enhanced ER stress and MUC5AC mRNA expression, suggesting a possible role in producing protective oxylipins in stressed cells. The results provide mechanistic insights and support for the purported benefits of Vasaka tea in treating lung inflammatory conditions, raising the possibility of further development as a preventative and/or restorative therapy.

Validation of Different Methods of Preparation of Adhatoda vasica Leaf Juice by Quantification of Total Alkaloids and Vasicine.

Leaf of Adhatoda vasica (Vasaka) is an important drug of Ayurveda, prescribed as an expectorant. Quinazoline alkaloids present in the leaves are established as active principles. In Ayurveda, its leaf juice (Vasa swarasa) is incorporated in many formulations. Classical method for extracting the juice (swarasa) from the leaf is an elaborate process, which involves subjecting a bolus of crushed fresh leaf to heat followed by squeezing out the juice. Commercially, to prepare the juice of Vasaka, manufacturers have been adopting different methods other than the traditional method. In an effort to evaluate these modified processes phytochemically to identify the process which gives juice of the quality that is obtained by traditional method, in terms of its alkaloid content, we prepared the leaf juice by traditional Ayurvedic method, its modification by steaming of leaf to simulate the traditional method and other methods adopted by some manufacturers. These juice samples were evaluated for the total alkaloid content by spectrophotometric method and vasicine content by thin layer chromatography densitometric method using high performance thin layer chromatography. The high performance thin layer chromatography method was validated for precision, repeatability and accuracy. The total alkaloid content varied from 0.3 mg/ml to 5.93 mg/ml and that of vasicine content varied from 0.2 mg/ml to 5.64 mg/ml in the juice samples prepared by different methods. The present study revealed that steaming of fresh leaves under 15 lb pressure yielded same quantity of juice as the traditional bolus method (25 ml/100 g leaf) and its total alkaloid content and vasicine content (4.05+/-0.12 and 3.46+/-0.06 mg/ml, respectively) were very high when compared to the other methods, though the traditional method was found to give the best quality juice with highest amount of total alkaloids (5.93+/-0.55 mg/ml) and vasicine (5.64+/-0.10 mg/ml) content.