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Background & objectives: Mosquitoes alone transmit diseases to around 700 million individuals annually, killing approximately 0.7 million people every year worldwide. Considering the potential health risks linked with synthetic repellents, it has become vital to identify eco-friendly, natural repellents for mosquito control as well as to understand the underlying mechanism for mosquito repellent activity. To address this, objectives were set to extract essential oils from Citrus macroptera peel and Homalomena aromatica (Spreng.) Schott. rhizomes, evaluate their mosquito repellent activity against Aedes aegypti, and further explore their mosquito odorant receptor inhibition potential. Methods: The oils were extracted using Clevenger's apparatus, and properties like specific gravity, refractive index, and boiling point were evaluated and characterised using Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectroscopy (GC-MS). Aedes aegypti mosquito eggs collected from the Indian Council of Medical Research (ICMR), Dibrugarh, were reared in the Department of Pharmaceutical Sciences, Research Laboratory, to obtain adult Aedes aegypti mosquitoes for the mosquito repellent activity evaluation of the essential oils using the Human Bait technique'. Molecular docking studies were performed for the oil components against mosquito odorant binding proteins. Further, toxicity studies of these two oils were evaluated against human dermal fibroblast adult (HDFa) cells. Results: The results revealed the presence of limonene (86.76%) and linalool (52.35%), respectively, in Citrus macroptera and Homalomena aromatica oils. It was found that the combination of the oils in a ratio of 1:1 showed mosquito repellent activity for up to 6.33 ± 0.23 h. Molecular docking studies showed the presence of major oil components having mosquito odorant receptor blocking potential comparable to N, N-diethyl-meta-toluamide (DEET), indicating a rationale for extended mosquito repellent action. Further, both of these oils were found to be non-cytotoxic against HDFa cells after 24 h. Interpretation & conclusion: The encouraging mosquito repellent activity of these two oils as compared to synthetic mosquito repellent DEET might pave the way for the development of novel herbal mosquito repellent formulations containing these essential oils.

Background Despite tremendous advancements in cancer treatment delivery, we are still far from achieving successful cancer prognosis and cure. The use of new nanocarriers for site-specific delivery of anticancer medicines with lower toxicity has shown promise. However, the successful translation of these works into products remains a challenge. Hence, a thorough examination of the various nanocarrier systems is required, with particular emphasis on the more recent approaches. Area Covered The review discusses how nanocarrier designs have evolved with each generation based on EPR, overexpressed receptors, stimuli-responsive systems, intracellular and extracellular targeting, immunotherapy, and the recent multifunctional theranostic approach, as well as their potential and limitations. The clinical translations of these systems, as well as the issues that have arisen, have been examined, along with potential future opportunities. Newer immunosystems and multifunctional theranostic methods have received special attention. Expert Opinion It has been observed that nanocarrier systems have evolved in three major generations. Despite all of the efforts, clinical success is limited to the first generation of EPR-based passive targeting. Active targeting is mostly limited to the preclinical stage. Tumor heterogeneity and poor delivery to the location remain a key worry and roadblock. Hence, the newer generation nanocarriers need a more multifunctional approach, combining active targeting with immunotherapy and diagnostic contrast agent delivery. Newer theranostic designs with combined effects of chemotherapy, immunotherapy, and other therapies such as photodynamic, photothermal, and photoacoustic need to be worked on. Besides, there is a need of finding new cancer markers, toxicity studies, and scale-up approaches to these nanosystems.

Background Equisetum diffusum D. Don commonly known as ‘Himalayan horsetail’, has been traditionally used in the treatment of back pain, bone fracture and dislocation, and arthritis by various tribal communities of India. Our previous study confirmed the anti-inflammatory efficacy of the plant through in silico, in vitro , and in vivo model studies. Therefore, the current research is focused on safety dose evaluation for the first-time of the whole-plant methanol extract (EDME) of E. diffusum through appropriate in silico, in vitro, and in vivo approaches. Method The whole plant, along with its rhizomes, was collected, and the methanol extract was prepared. The in silico ADMET study was performed to predict the pharmacokinetics profile and toxicity of all the identified phyto-compounds of EDME previously screened by GC–MS study. In vitro cytotoxicity study of EDME was performed using two cell lines: kidney (HEK293) and liver (Huh7) cell lines. The in vivo toxicity study of EDME was validated by the acute toxicity (OECD 423, 2002) and sub-acute toxicity assays (OECD 407, 2008) in the Wistar Albino rat model. Results The in silico ADMET study of all 47 bioactives predicted good pharmacokinetic and low toxicity profiles. In vitro cytotoxicity showed higher IC 50 values of EDME viz., 672 ± 15.7 μg/mL and 1698 ± 6.54 μg/mL for both kidney (HEK293) and liver (Huh7) cell lines, respectively, which were considered as low-toxic. Based on acute oral toxicity, the LD 50 value of the extract was considered “non-toxic” up to a feeding range of 2000 mg/kg of body weight. The regular consumption of the extract for an extended period (28 days) was also qualified as safe based on the body and organ weight, hematological, biochemical, and histoarchitecture results in the sub-acute toxicity assay. Conclusion The detailed in silico , in vitro , in vivo (acute and sub-acute oral toxicity) studies gave us a new insight to the safety dose evaluation of Equisetum diffusum , which may serve as a reliable documentation for undertaking the experimental validation of the ethnobotanical uses of the plant which would help in the field of drug development for the treatment of inflammation related complications.

Background Lung cancer remains a leading cancer type, but current chemotherapy is limited by issues including poor drug delivery, toxicity, and resistance. To address these challenges, we developed a novel PLGA-PEG-LHRH (PPL) nanoconjugate system for improved drug delivery. Curcumin, known for its anticancer and P-gp inhibition properties, was co-loaded with bcl2siRNA (bclsR) to inhibit the bcl2 protein, thus overcoming both resistance mechanisms. Results The PPL conjugate was successfully synthesized and characterized using FTIR, 1 H NMR, XRD, XPS and BCA assay. Curcumin and bclsR-loaded PLGA nanoemulsions were prepared by double emulsion solvent evaporation method and characterized. The optimized nanoconjugate had size of 179 ± 16 nm, favorable zeta potential, high drug entrapment, and was confirmed via TEM. Controlled release studies indicated 83% drug release within 24 h. In vitro studies revealed significant cytotoxicity against A549 lung cancer cells, with the nanoconjugate showing IC50 of 8.24 µg/mL compared to 21.26 µg/mL for plain curcumin. Enhanced cellular uptake and effective targeting of A549 cells were observed. Molecular analyses demonstrated significant downregulation of MDR1 and Bcl2 RNA and protein expression, highlighting the nanoconjugates' ability to suppress resistance mechanisms. Pharmacokinetic studies in Wistar rats showed superior plasma drug concentrations, half-life, and AUC for the nanoconjugate versus pure drug suspension. Biodistribution studies showed increased drug accumulation in the lungs. In vivo efficacy studies in Balb/c mice demonstrated higher tumor inhibition ratios for CUR-siRNA PPL NPs (66.89%) and CUR-PPL NPs (59.84%) which was further confirmed with TNFα and p53 levels in blood. Histopathological studies showed good healing in the CUR-siRNA PPL NP- and CUR-PPL NP-treated mice compared to suspension. Conclusion From the study, it may be concluded that the PPL nanoconjugate system, loaded with curcumin and bcsR, can be potentially effective, multifunctional targeted approach for lung cancer therapy. Graphical Abstract

Triterpenes are naturally occurring derivatives biosynthesized following the isoprene rule of Ruzicka. The triterpenes have been reported to possess a wide range of therapeutic applications including anti-viral properties. In this review, the recent studies (2010–2020) concerning the anti-viral activities of triterpenes have been summarized. The structure activity relationship studies have been described as well as brief biosynthesis of these triterpenes is discussed.

Purpose Ursolic acid (UA), a pentacyclic triterpenoid extracted from plants, shows promising inhibitory effect in different tumor bearing cell lines. In the present study we fabricated UA loaded PLGA nanoparticles (UA-NPs) as the drug carrier and thoroughly evaluated in vitro and in vivo the differential tumor targeting effects of UA and UA-NPs in B16F10 melanoma cells. Methods Ursolic acid loaded PLGA nanoparticles were prepared by emulsion solvent evaporation technique and evaluated for particle size, polydispersity, zeta potential and drug release potency. MTT assay as well as flow cytometric and confocal microscopic analyses were done in B16F10 mouse melanoma cell lines. Formulations were labeled with technetium-99m to evaluate the biodistribution and perform scintigraphic imaging studies following intravenous administration in tumor bearing mice model. Results Single emulsification technique produced smooth spherical nanoparticles of small size with relatively narrow size distribution (154 ± 4.56 nm). On B16F10 cell line, the formulation showed higher cytotoxicity compared to the free drug due to increased in vitro cellular uptake. The formulation was successfully radiolabeled and remained substantially (>90%) stable when incubated (37°C, 6 h) separately in normal saline or freshly collected rat serum or histidine solution. The radiolabeled UA-NPs exhibited slower blood clearance and comparatively high uptake in tumor region as evidenced by biodistribution and scintigraphic studies. Conclusions The in vitro and in vivo studies have proved the tumor targeting potential of UA-NPs in B16F10 melanoma cell lines.

In recent years the authors have reported on 99mTc(CO)3-labeled peptides that serve as carriers for biomolecules or radiopharmaceuticals to the tumors. In continuation of that work they report the synthesis of a pentapeptide (Met-Phe-Phe-Gly-His; pep-1), a hexapeptide (Met-Phe-Phe-Asp-Gly-His; pep-2), and a tetrapeptide (Asp-Gly-Arg-His; pep-3) and the attachment of 3-amino-1,2,4-triazole to the β carboxylic function of the aspartic acid unit of pep-2 and pep-3. The pharmacophores were radiolabeled in high yields with [99mTc(CO)3(H2O)3]+ metal aqua ion, characterized for their stability in serum and saline, as well as in His solution, and found to be substantially stable. B16F10 cell line binding studies showed favorable uptake and internalization. In vivo behavior of the radiolabeled triazolyl peptides was assessed in mice bearing induced tumor. The 99mTc(CO)3-triazolyl pep-3 demonstrated rapid urinary clearance and comparatively better tumor uptake. Imaging studies showed visualization of the tumor using 99mTc(CO)3-triazolyl pep-3, but due to high abdominal background, low delineation occurred. Based on the results further experiments will be carried out for targeting tumor with triazolyl peptides.

In recent years the authors have reported on (99m)Tc(CO)3-labeled peptides that serve as carriers for biomolecules or radiopharmaceuticals to the tumors. In continuation of that work they report the synthesis of a pentapeptide (Met-Phe-Phe-Gly-His; pep-1), a hexapeptide (Met-Phe-Phe-Asp-Gly-His; pep-2), and a tetrapeptide (Asp-Gly-Arg-His; pep-3) and the attachment of 3-amino-1,2,4-triazole to the β carboxylic function of the aspartic acid unit of pep-2 and pep-3. The pharmacophores were radiolabeled in high yields with [(99m)Tc(CO)3(H2O)3](+) metal aqua ion, characterized for their stability in serum and saline, as well as in His solution, and found to be substantially stable. B16F10 cell line binding studies showed favorable uptake and internalization. In vivo behavior of the radiolabeled triazolyl peptides was assessed in mice bearing induced tumor. The (99m)Tc(CO)3-triazolyl pep-3 demonstrated rapid urinary clearance and comparatively better tumor uptake. Imaging studies showed visualization of the tumor using (99m)Tc(CO)3-triazolyl pep-3, but due to high abdominal background, low delineation occurred. Based on the results further experiments will be carried out for targeting tumor with triazolyl peptides.