High performance thin layer chromatography qualitative densitometry as a sensitive method to assess shelf life of polyherbal formulations: A study on Hutabhugadi Churna.

INTRODUCTION: Measuring chemical stability of polyherbal formulations is very challenging due to diversity in phytochemical composition. As there are no comprehensive guidelines for stability testing of herbal products, there is a need for a sensitive tool to detect how the quality of herbal products varies with time under the influence of environmental conditions. AIMS: To validate the employability of high-performance thin layer chromatography (HPTLC) for real-time stability of Hutabhugadi Churna (HC). MATERIALS AND METHODS: The chromatograms were developed using toluene/ethyl acetate/formic acid (10:5:1) and ethyl acetate/formic acid (10:1) as a mobile phase for chloroform and ethanolic extract, respectively. The plates were scanned under 254, 366, 540 (pre-derivatization) and 540 nm (post-derivatization). Samples were analyzed immediately after preparation and after 3(rd) and 6(th) months of storage. Alteration of fingerprint profiles from the initial pattern, in terms of number of peaks, was employed as diagnostic tools. Percentage variation in composition at given period was calculated. RESULTS: HC is found to be stable at room temperature up to 1.3 months using the method of calculation of 10% degradation period employing slope and intercept values for the initial, 3(rd) and 6(th) months' deviation in number of bands. The data obtained were subjected to regression analysis in context to number of bands obtained. The curve was found to be linear with R(2) value of 0.89-0.96 supported by their tolerance range of 0.04-0.11. CONCLUSION: The proposed model is a new logic with prospects to become working method for stability assessment of polyherbal formulations under controlled conditions.

Synthesis of some halogen-containing 1,2,4-triazolo-1,3,4-thiadiazines and their antibacterial and anticancer screening studies--part I.

A series of 7-arylidene-6-(2,4-dichloro-5-fluorophenyl)-3-substituted-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines (3) were prepared by the condensation of 4-amino-5-mercapto-3-substituted-1,2,4-triazoles (1) and 3-aryl-1-(2,4-dichloro-5-fluorophenyl)-2-bromo-2-propen-1-one (2). An alternative route for the synthesis of the title compound 3 has been described. The newly synthesised compounds were characterised on the basis of N-analyses, IR, 1H NMR and mass spectral data. Some of the newly synthesised compounds were tested for their antibacterial activities against Gram + ve and Gram - ve bacteria. Among the tested compounds 3n showed the highest degree of antibacterial activity against S. aureus and evaluation of the LD50 value of this compound was carried out. Some of the newly synthesised compounds were also screened for their anticancer activities. Among these, compounds 3b, 3g, 3n and 3p are found to be active against NCI-H460 (lung), MCF7 (breast), SF 268 (CNS) in the preliminary anticancer screening studies. Further, 60-cell-line anticancer studies of these compounds were carried out. The results of such studies are discussed in this paper.

Synthesis of some new biologically active bis-(thiadiazolotriazines) and bis-(thiadiazolotriazinyl) alkanes.

4-Amino-3-mercapto-1,2,4-triazin-5(4H)-ones (1) were condensed with dicarboxylic acids 2 to yield bis-(4-oxo-4H-1,3,4-thiadiazolo[2,3-c]-1,2,4-triazin-7-yl)alkanes (3b-d,f-h,j-l,n-p) and bis-thiadiazolotriazines (3a,e,i,m). All the newly synthesised compounds were characterised by analytical, IR, NMR and mass spectral studies. Some of the newly synthesised compounds were screened for their antibacterial and antifungal properties. Among the tested compounds, compound 7,7'-(1,4-butanediyl)-his-(3-t-butyl-4-oxo-4H-1,3,4-thia-diazolo[2,3-c]-1,2,4-triazine (3p) exhibited highest degree of antifungal activity.

Studies on nitrophenylfuran derivatives part Xii. synthesis, characterization, antibacterial and antiviral activities of some nitrophenylfurfurylidene-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines.

Synthesis of four 1-aryl-3-[5-(p-nitrophenyl)-2-furyl]-2-propen-1-ones starting from substituted acetophenones and p-nitrophenylfurfuraldehyde is described. These propenones were then converted into corresponding dibromo derivatives which on dehydrobromination afforded alpha-bromopropenones rather than acetylenic ketones. Condensation of these dibromopropanones with 4-amino-5-mercapto-1,2,4-triazoles yielded a new class of nitrophenylfurfurylidene-1,2,4-triazolothiadiazines. The structures of nitrophenylfurfurylidene-1,2,4-triazolothiadiazines were established on the basis of analytical, IR, NMR and mass spectral studies. The formation of 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines rather than 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazepines in the above condensation was unambiguously confirmed by X-ray crystallographic analysis of one of them. A possible mechanism is proposed to account for the formation of nitrophenylfurfurylidene-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines. Some of the newly synthesized triazolothiadiazines were screened for their antibacterial and antiviral properties.

Studies on arylfuran derivatives. Part XI. Synthesis, characterisation and biological studies on some Mannich bases carrying 2,4-dichlorophenylfurfural moiety.

A series of 3-substituted-4-[5-(2,4-dichlorophenyl)-2-furfurylidine]amino-5-me rcapto-1, 2,4-triazoles (3) are synthesised. Aminomethylation of 3 with formaldehyde and a primary/secondary amine furnished Mannich bases 4 and 5. Both Schiff bases 3 and Mannich bases 4 and 5 are characterised on the basis of IR, 1H NMR, mass spectral data and elemental analysis. All the newly synthesised compounds are tested for their antibacterial activities. Some of the selected compounds are also tested for their fungicidal and herbicidal properties.

Studies on arylfuran derivatives: part X. Synthesis and antibacterial properties of arylfuryl-delta2-pyrazolines.

Arylfurylpropenones 3 were synthesized by Claisen-Schmidt condensation of arylfurfurals 1 with various substituted acetophenones 2. Cyclocondensation of these arylfurylpropenones 3 with hydrazine hydrate and phenylhydrazine furnished 1H-pyrazolines 4 and N-phenylpyrazolines 6, respectively. In order to study the structure-activity relationships, pyrazolines 4 were converted into their N-acetyl derivatives 5. The antibacterial properties of the new pyrazoline derivatives were studied.

Synthesis and antibacterial studies of a new series of 1,2-bis(1,3, 4-oxadiazol-2-yl)ethanes and 1,2-bis(4-amino-1,2, 4-triazol-3-yl)ethanes.

The acylhydrazones 3, obtained by the treatment of succinic acid dihydrazide 2 with furfural, nitrofurfuraldehydediacetate and substituted arylfurfurals, on oxidative cyclization with bromine in acetic acid yielded 1,2-bis(1,3,4-oxadiazol-2-yl)ethanes 4 which are further converted into 1,2-bis(4-amino-1,2,4-triazol-3-yl)ethanes 5 with hydrazine hydrate. The newly synthesised compounds are characterised by analytical, IR, NMR and mass spectral data. Most of the newly synthesised compounds have been found to be active against both Gram positive and Gram negative bacteria at less than 6 microg/mL concentration.

Synthesis of some new biologically active thiadiazolotriazinones--Part II.

4-Amino-6-phenyl/methyl-3-mercapto-1,2,4-triazin-5(4H)-ones (1) are condensed with an aromatic carboxylic acid, aryloxyacetic acid or anilinoacetic acid (2), to yield 7-substituted-3-phenyl/methyl-4H-1,3,4-thiadiazolo-[2,3-c]-1,2,4-+ ++triazin-4- ones (3). Phosphorus oxychloride is used as a cyclizing agent. All the synthesized compounds are screened for their antibacterial activities against S. aureus, E. coli, P. aeruginosa and G. bacillus.

Studies on arylfuran derivatives- Part VIII. Synthesis, characterization and antibacterial activities of some 1-aminomethyl-3-substituted-4-[5-(4-nitrophenyl-2-furfurylidene)] amino-1,2,4-triazole-5-thiones.

A series of 4-[5-(4-nitrophenyl-2-furfurylidene)]amino-5- mercapto-3-substituted-s-triazoles (3) and their Mannich bases (4) are synthesized. The structures of these compounds are established on the basis of elemental analysis, IR, NMR and mass spectral data. The newly synthesized compounds are screened for their antibacterial activities.

Synthesis of some new biologically active thiadiazolotriazinones.

4-Amino-6-arylmethyl-3-mercapto-1,2,4-triazin-5(4H)-ones 1 are condensed with aromatic carboxylic acids, aryloxyacetic acids and anilinoacetic acids 2 to yield 7-substituted-3-arylmethyl-4H-1,3,4-thiadiazolo[2,3-c]-1,2,4-tr iazin-4-ones 3. Phosphorus oxychloride is used as cyclizing agent. Some of the newly synthesized compounds are screened for their antibacterial activities.

Studies on arylmethyltriazinone derivatives-Part II. Synthesis and antifungal properties of 2-aminomethyl-4-(arylidene)amino-6-arylmethyl- 3-mercapto-1,2,4-triazin-5(4H)-ones.

The preparation of twenty new 2-aminomethyl-4-(arylidene)amino- 6-arylmethyl-3-mercapto-1,2,4-triazin-5(4H)-ones(4) is described. The structural elucidation of all the compounds is carried out on the basis of analytical and spectral data. The newly synthesized compounds are evaluated for their antifungal activity against Candida albicans and Paecileomyces variotti.

Synthesis of biologically active bis-[4-amino-5-mercapto-1,2,4- triazol-3yl]-alkanes and their derivatives.

The preparation of bis-(4-amino-5-mercapto-1,2,4-triazol-3yl)alkanes is described. These bis-(amino-mercapto-triazolyl) alkanes are characterized by analytical and spectral data. They are also characterized by the preparation of the Schiff bases by condensing them with various benzaldehydes and nitro furfural diacetate in dimethyl formamide-ethanol medium in the presence of concentrated sulphuric acid. The structures of Schiff bases are assigned based on analytical and spectral data. The newly synthesized compounds are screened for their antibacterial properties against Gram-positive and Gram-negative bacteria. Most of them showed significant activity.

Studies on arylfuran derivatives. Part VII. Synthesis and characterization of some Mannich bases carrying halophenylfuryl moieties as promising antibacterial agents.

A series of 4-[5-(halophenyl)-2-furfurylidene)] amino-3-mercapto-5-substituted-1,2,4-triazoles (3) were synthesized. Aminomethylation of 3 with formaldehyde and a secondary amine furnished Mannich bases, 4. Both Schiff bases and Mannich bases were characterized on the basis of IR, NMR, mass spectral data and elemental analysis. All the newly synthesized compounds were tested for their antibacterial activities. Some of them carrying morpholino and N-methylpiperazino residues were found to be promising antibacterial agents.

Studies on some N-bridged heterocycles derived from bis-[4-amino-5-mercapto-1,2,4-triazol-3-yl] alkanes.

A series of bis-[4-amino-5-mercapto-1,2,4-triazol-3-yl] alkanes have been synthesized and were converted into bis-[1,2,4-triazolo[3,4-b]-1,3,4-thiadiazol-4-yl] alkanes. The newly synthesized compounds were characterized by analytical IR, NMR and mass spectral studies. Some of the newly synthesized compounds were screened for their antibacterial properties and exhibited activity with MIC in the range 3-12.5 micrograms/ml.

Studies on arylfuran derivatives-Part VI. Synthesis, characterization and antibacterial activities of some 6-(5-aryl-2-furyl)-1,2,4-triazolo [3,4-b]-1,3,4-thiadiazoles and 6-(5-nitro-2-furyl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles.

A series of 4-[5-aryl-2-furfurylidene]amino-3-mercapto-5-substituted-1,2,4-tri azoles and 4-[5-Nitro-2-furfurylidene]amino-3-mercapto-5-substituted-1,2,4-tr iazoles have been synthesized and were converted into 1,2,4-triazolo [3,4-b]-1,3,4-thiadiazoles. These triazolothiadiazoles are also synthesized by an alternative method in better yields employing arylfuroic acids and s-triazoles in the presence of phosphorus oxychloride. The newly synthesized compounds are screened for their antibacterial properties.

Synthesis, characterisation and antifungal activity of some N-bridged heterocycles derived from 3-(3-bromo-4-methoxyphenyl)-4-amino-5-mercapto-1,2,4-triazole.

3-(3-Bromo-4-methoxyphenyl)-4-amino-5-mercapto-1,2,4-triazole was prepared starting from p-anisic acid. This new triazole was employed in the synthesis of some N-bridged heterocycles. All the newly synthesized compounds were characterized by analytical, IR, 1H-NMR and Mass Spectral studies. Some of the newly synthesized compounds were screened for their antifungal property against Thielaviopsis paradoxa, a fungus which is reported to cause stem-bleeding disease in coconut plants.

Studies on the synthesis and biological activity of 3-(substituted anilinomethyl)-4-(5-substituted-2-furfurylidene)amino-1,2,4 -triazole-5- thiones and their Mannich bases.

A series of 3-(substituted anilinomethyl)-4-(5-substituted-2- furfurylidene)amino-1,2,4-triazole-5-thiones were synthesized as potential biologically active agents. They were converted to Mannich bases, by treating with suitable amine in the presence of formaldehyde in alcohol medium. The newly synthesized compounds were screened for their antibacterial and antifungal activities.

Studies on arylfuran derivatives--Part V. Synthesis and antibacterial properties of 7H,6-[5-(4-nitrophenyl)-2-furyl]-1,2,4-triazolo [3,4-b]-1,3,4-thiadiazines.

The preparation of fifteen new 7H, 6-[5-(4-nitrophenyl)-2-furyl]-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine is described. The structural elucidation of all the compounds is carried out on the basis of analytical and spectral data. The newly synthesized compounds are evaluated for their antibacterial activity against both Gram-positive and Gram-negative bacteria.

Studies on arylfuran derivatives--Part IV. Synthesis and antibacterial properties of arylfurylvinylquinazolinones.

A number of arylfurylvinylquinazolinones were prepared as possible antibacterial agents. The structural elucidations of all the compounds were carried out on the basis of analytical and spectral data. The newly synthesised compounds were screened for their antibacterial properties against both Gram-positive and Gram-negative bacteria.

A new class of substituted 1,2,4-triazolo-1,3,4-thiadiazepines.

A series of 3-aryloxymethyl-(5-nitro-2-furyl)-6-phenyl-1,2,4- triazolo[3,4-b][1,3,4]thiadiazepine compounds have been synthesized recently by a new route. Reported here are the structures of two such compounds with para-substituted aryloxymethyl groups: one has a chloro group, 3-(4-chlorophenyl-oxymethyl)-8-(5-nitro-2-furyl)-6-phenyl-1,2,4- triazolo[3,4-b][1,3,4]thiadiazepine, C22H14C1N5O4S, TD1, and the other a methyl group, 3-(p-tolyloxy-methyl)-8-(5-nitro-2-furyl)-6-phenyl-1,2,4- triazolo-[3,4-b][1,3,4]thiadiazepine, C23H17N5O4S, TD7. The nitrofuryl and phenyl groups on the thiadiazepine ring are each found to adopt a similar conformation in the two structures, whereas the aryloxymethyl substituents on the triazole rings are conformationally different from each other. Each thiadiazepine ring adopts a boat conformation with the S atom at the apex. The interplanar angle between the triazole ring and the thiadiazepine ring is 30 degrees for both compounds. The conformation of the aryloxy-methyl group is dependent on the intermolecular interactions that arise as a result of the polarity of the para substituent. The Cl group in TD1 is involved in a C-Cl...O non-bonded interaction with a Cl...O distance of 3.100 (3) A and a C-Cl...O angle of 138.4 (1) degree. TD7 has a stacking interaction involving the nitrofuryl groups.