Arun D. Natu

Artemisia pallens alleviates acetaminophen induced toxicity via modulation of endogenous biomarkers

Abstract Context: Acetaminophen (APAP) leads to severe hepatic and renal necrosis and thus causes significant clinical problems. Artemisia pallens Walls ex D.C. (Asteraceae) possesses various pharmacological properties such as antidiabetic, antioxidant, analgesic, and anti-inflammatory activity. Objective: The objective was to evaluate the protective effects of Artemisia pallens methanol extract (APME) in APAP-induced hepatic and nephro-toxicity. Materials and methods: The methanolic extract of aerial parts of Artemisia pallens (APME) was prepared. Toxicity was induced in male Wistar rats (180–220 g) by administration of APAP (700 mg/kg, p.o., 14 d). APME (100, 200, and 400 mg/kg, p.o.) was administered to rats 2 h before APAP oral administration. Various biochemical and molecular parameters along with histopathological aberration were studied in the kidney and liver of rats. Results: Pretreatment with APME (200 and 400 mg/kg, p.o.) significantly (p < 0.01 and p < 0.001) decreased aspartate transaminase (AST), alanine transaminase (ALT), bilirubin, blood urea nitrogen (BUN), and serum creatinine as compared with APAP-treated rat. Decreased level of serum albumin, serum uric acid, and HDL were significantly (p < 0.01 and p < 0.001) restored by APME (200 and 400 mg/kg, p.o.) pre-treatment. Administration of APME (200 and 400 mg/kg, p.o.) significantly (p < 0.01 and p < 0.001) reduced the elevated level of cholesterol, LDL, LDH, triglyceride, and VLDL. It also significantly (p < 0.01 and p < 0.001) restored the altered level of hepatic and renal antioxidant enzymes (superoxide dismutase (SOD) and glutathione (GSH)). The increased level of malondialdehyde (MDA) and nitric oxide (NO) in hepatic as well as renal tissue was significantly (p < 0.01 and p < 0.001) decreased by APME (200 and 400 mg/kg, p.o.) administration. Histological alternation induced by APAP in liver and kidney was also reduced by the APME (200 and 400 mg/kg, p.o.) pre-treatment. Conclusion: It is concluded that the methanol extract of Artemisia pallens alleviates APAP induced in rats toxicity through its antioxidative and anti-inflammatory actions.

One pot solvent free synthesis and in vitro antitubercular screening of 3-Aracylphthalides against Mycobacterium tuberculosis

One pot synthesis of 3-Aracylphthalide was accomplished in good yield by reacting 2-carboxy benzaldehyde with various aromatic methyl ketones in presence of methane sulphonic acid. Various phthalides thus obtained were characterized with spectral techniques. These phthalides were subjected to in vitro antitubercular screening against Mycobacterium tuberculosis H37Ra (MTB) by using XRMA protocol. Among the phthalides screened, four exhibited half maximal inhibitory concentration (IC(50)) in the range of 0.81-1.24 μg/ml thereby providing potential lead compounds for future drug discovery studies.

Facile and Highly Selective Deprotection of tert‐Butyldimethyl Silyl Ethers using Sulfated SnO2 as a Solid Catalyst

Abstract Highly selective deprotection of tert‐butyldimethylsilyl ethers at room temperature has been described using sulfated SnO2 as an efficient solid catalyst.

Unusual Trisulphide Linkage in Bromine–Thiourea Reaction: Crystal Structure of Formamidinium Trisulphide Complex with Bromine

A new complex of formamidinium trisulphide with bromine has been synthesized. Single-crystal X-ray analysis of this compound revealed a novel trisulphide linkage in the formamidinium trisulphide moiety. The crystals belong to orthorhombic space group Fdd2 with a = 14.9119(15), b = 16.5241(17), c = 8.5114(9) Å, V = 2097.3(4) Å3, R1 = 0.0326, and wR2 = 0.0846 for 2666 reflections. All four amine groups are hydrogen linked to four different formamidinium trisulphide molecules through bromine atoms, making a beautiful three-dimensional network of hydrogen bonds, which stabilize the crystal structure.

In vitro and ex vivo antitubercular activity of diarylheptanoids from the rhizomes of Alpinia officinarum Hance

Abstract Phytochemical investigation of methanol extract of the rhizomes of Alpinia officinarum Hance afforded four known diarylheptanoids 1,7-diphenylhept-4-en-3-one (1), 5-hydroxy-1,7-diphenyl-3-heptanone (2), 5-hydroxy-7-(4″-hydroxy-3″-methoxyphenyl)-1-phenyl-3-heptanone (3), and 7-(4″-hydroxy-3″-methoxyphenyl)-1-phenyl heptan-3-one (4).The acetate derivative of (4), 7-(4″-actetate-3″-methoxy phenyl)-1-phenyl heptan-3-one (5), was prepared. These diarylheptanoids exhibited promising in vitro and ex vivo antitubercular activity for the first time against dormant Mycobacterium tuberculosis H37Ra with the IC50 values between 0.34–47.69 and 0.13–22.91 μM, respectively. All compounds showed comparable activity against Mycobacterium bovis BCG (dormant phage) and did not show any activity against two gram + ve and two gram –ve bacterial strains. These compounds were also weakly cytotoxic up to 300 μM against three human cancer cell lines THP-1, Panc-1 and A549.

Synthesis of Naturally Occurring Pyranonaphthoquinones: (±) 9-Demethoxyeleutherin, (±) 9-Demethoxyisoeleutherin, and Pentalongin via Nef Reaction

Abstract The article describes alternative method for the synthesis of (±) 9-demethoxyeleutherin and (±) 9-demethoxyisoeleutherin, the analogs of naturally occurring pyranonaphthoquinones antibiotics eleutherin and isoeleutherin. This methodology has provided the target molecules using a shorter route involving five simple chemical transformations with Nef reaction as a key step. All the intermediates and target molecules were completely characterized by spectral techniques and confirmed by comparison with literature data. Further we have extended Nef protocol toward formal synthesis of naturally occuring pyranonaphthoquinone pentalongin. We accomplished synthesis of of 2-(1,4-dimethoxynaphthalen-2-yl)acetic acid devoid of very toxic cyanide intermediates, which has been converted into pentalongin. GRAPHICAL ABSTRACT

Convenient syntheses of 3‑aryl‑3,4‑dihydroisocoumarins

A convenient method for the synthesis of naturally occurring 3,4-dihydroisocoumarins by judicious use of Friedel-Craft acylation, regioselective formylation and oxidative cyclisation reactions is described. O-methylated analogues of montroumarin and thunberginols C and D and have been synthesised using 3,5-dimethoxyphenylacetic acid as a starting material. Furthermore, the starting material 3,5-dimethoxyphenylacetic acid was synthesised by a route involving an oxidative Nef reaction.

CONVENIENT SYNTHESIS OF 2-ALLYL-3-BROMO-1,4- DIMETHOXYNAPHTHALENE: KEY INTERMEDIATE AS BUILDING BLOCK FOR BIOACTIVE PYRANONAPHTHOQUINONES

Abstract Synthesis of a key precursor 2-allyl-3-bromo-1,4-dimethoxynaphthalene (1) used in constructing various naturally occurring biologically active pyranonaphthoquinones is carried out utilizing easily available 1-methoxynaphthalene as a starting material. The synthesis was accomplished with Dakins oxidation and Claisen rearrangement, thereby providing another easy approach toward (1) without involving highly lachrymatric 2-bromonaphthoquinone. GRAPHICAL ABSTRACT

Efficient total synthesis of naturally occurring anti-TMV compound gramniphenol G

ABSTRACT An efficient synthesis of Gramniphenol G identified as 2-(4′-Methoxyphenyl)-7,7-dimethyl-7H-furo[3,2-g]chromene and originally isolated from the plant Arundina gramnifolia belonging to orchidaceae family was accomplished starting from resorcinol. The key step involves the oxidative cyclization of o-vinyl phenol to provide benzofuran moiety. GRAPHICAL ABSTRACT

Convenient synthesis of bioactive pyranonaphthoquinones (±)9-demethoxyeleutherin and (±)9-demethoxyisoeleutherin

A convenient synthesis of (±)9-demethoxyeleutherin and (±)9-demethoxyisoeleutherin, the analogues of naturally occurring pyranonaphthoquinone antibiotics eleutherin and isoeleutherin, is described. The synthesis was achieved from 4-methoxy-1-napthol in four simple steps including Claisen rearrangement and oxymercuration–demercuration reactions.