Nandini Sharma

A comprehensive review on vanilla flavor: extraction, isolation and quantification of vanillin and others constituents.

Vanilla, being the worlds most popular flavoring materials, finds extensive applications in food, beverages, perfumery and pharmaceutical industry. With the high demand and limited supply of vanilla pods and the continuing increase in their cost, numerous efforts of blending and adulteration in natural vanilla extracts have been reported. Thus, to ensure the quality of vanilla extracts and vanilla-containing products, it is important to develop techniques to verify their authenticity. Quantitatively, vanillin is the major compound present in the vanilla pods and the determination of vanillin is a vital consideration in natural vanilla extracts. This paper provides a comprehensive account of different extraction processes and chromatographic techniques applied for the separation, identification and determination of chemical constituents of vanilla. The review also provides an account of different methods applied for the quantification and the authentification of chemical constituents of vanilla extract. As the various properties of vanilla are attributed to its main constituent vanillin, its physico-chemical and bioactive properties have also been outlined.

Isolation and Identification of a Novel Strain of Pseudomonas chlororaphis Capable of Transforming Isoeugenol to Vanillin

Vanillin is undoubtedly one of the most popular and widely used flavoring agents in the world. Taking into consideration the worldwide demand for natural vanillin and its limited supply, alternative routes for its production including biotransformation are being constantly explored. In this regard, a novel soil bacterium capable of converting isoeugenol to vanillin was isolated by conventional enrichment process from soils of Ocimum field. On the basis of morphological and physiochemical characteristics and 16S rRNA gene sequence analysis, the isolate was identified as Pseudomonas chlororaphis CDAE5 (EMBL # AM158279). Vanillin formation was analyzed by gas chromatography (GC), and its structure was confirmed by GC-mass spectrometry and nuclear magnetic resonance. After 24-h reaction, the vanillin concentration reached 1.2 g L−1 from 10 g L−1 isoeugenol in 20-mL reaction solution at 25°C and 180 rpm. The strain showed potential to be a good candidate for biotechnological production of vanillin from isoeugenol. Further studies for standardization and optimization for higher yield of vanillin production needs to be investigated.

Green and recyclable glycine nitrate (GlyNO3) ionic liquid triggered multicomponent Biginelli reaction for the efficient synthesis of dihydropyrimidinones

Herein we report the use of an amino acid ionic liquid as a green catalyst for the multicomponent synthesis of 3,4-dihydropyrimidin-2(1H)-ones in excellent yields and short reaction time. The ionic liquid is inexpensive and biodegradable and can be reused for more than ten consecutive reactions. The potential of the protocol for gram scale synthesis adds to its practical applicability.

Qualitative and quantitative analysis of anthraquinone derivatives in rhizomes of tissue culture-raised Rheum emodi Wall. plants.

This paper presents quantification of five anthraquinone derivatives (emodin glycoside, chrysophanol glycoside, emodin, chrysophanol and physcion) in rhizomes of hardened micro-propagated Rheum emodi plants using high-performance liquid chromatography (HPLC). Aseptic shoot cultures were raised using rhizome buds. Shoot multiplication occurred in both agar gelled and liquid Murashige and Skoog (MS) medium supplemented with 10.0 microM 6-benzylaminopurine (BAP) and 5.0 microM indole-3-butyric acid (IBA). Rooted plantlets obtained on plant growth regulator (PGR)-free medium were transferred to soil with 92% survival. HPLC analysis revealed the presence of five anthraquinone derivatives: emodin glycoside, chrysophanol glycoside, emodin, chrysophanol and physcion in rhizomes of tissue culture-raised plants. Only emodin glycoside (1) and chrysophanol glycoside (2) were present in 6-month-old hardened tissue cultured plants. In addition, the other three derivatives (emodin (3), chrysophanol (4) and physcion (5)) were also detected after 9 months.

Biocatalysts for multicomponent Biginelli reaction: bovine serum albumin triggered waste-free synthesis of 3,4-dihydropyrimidin-2-(1H)-ones.

Bovine serum albumin (BSA) promoted simple and efficient one-pot procedure was developed for the direct synthesis of 3,4-dihydropyrimidin-2(1H)-ones including potent mitotic kinesin Eg5 inhibitor monastrol under mild reaction conditions. The catalyst recyclability and gram scale synthesis have also been demonstrated to enhance the practical utility of process.

Microwave-Assisted Efficient Extraction and Stability of Juglone in Different Solvents from Juglans regia: Quantification of Six Phenolic Constituents by Validated RP-HPLC and Evaluation of Antimicrobial Activity

Abstract In the present study, microwave-assisted extraction was compared with conventional approaches for the efficient extraction of juglone and other phenolics from Juglans regia bark. The effect of different solvents was also studied and ethyl acetate was found to be a better solvent in terms of juglone yield and stability. Further, a simple and fast RP-HPLC method was developed and validated for the determination of juglone and other bioactive phenolics like gallic acid, caffeic acid, quercetin, myricetin, and quercitrin in these extracts. In addition, the extracts were tested for antimicrobial activity against 16 microorganisms where all the extracts showed broad spectrum activity.

gIsolation and purification of acetylshikonin and β-acetoxyisovalerylshikonin from cell suspension cultures of Arnebia euchroma (Royle) Johnston using rapid preparative HPLC*

Shikonin and its derivatives are important red colored naphthoquinone pigments found in a large number of Arnebia species, including A. euchroma, that are responsible for the various pharmacological activities exhibited by the plant. The precise separation of each naphthoquinone is essential for total quality evaluation and bioactivity analysis of herbal formulations of A. euchroma. Furthermore, the overexploitation of this useful plant has resulted in species becoming endangered. With this in mind, a simple and rapid preparative scale HPLC method with single compound recovery for the isolation and purification of two shikonin derivatives (i. e. acetylshikonin, beta-acetoxyisovalerylshikonin) from cell suspension cultures of A. euchroma is presented. The compounds were separated on a C(18) column within 10 min using acetonitrile/methanol (95:5) as mobile phase in isocratic mode. The isolated compounds were found to be more than 98% pure. The LOD for acetylshikonin and beta-acetoxyisovalerylshikonin was estimated at 0.063 and 0.146 mug/mL, respectively, while the LOQ was found to be 0.209 and 0.487 mug/mL, respectively. The recoveries accomplished for both the shikonin derivatives were in the range of 94.7-96.8%. The repeatability, expressed as %RSD, of acetylshikonin and beta-acetoxyisovalerylshikonin was found to be 1.74 and 1.27, respectively.

Simultaneous densitometric determination of shikonin, acetylshikonin, and β-acetoxyisovaleryl-shikonin in ultrasonic-assisted extracts of four Arnebia species using reversed-phase thin layer chromatography.

A simple, precise, and rapid high-performance thin-layer chromatographic (HPTLC) method for the simultaneous quantification of pharmacologically important naphthoquinone shikonin (1) together with its derivatives acetylshikonin (2), and beta-acetoxyisovalerylshikonin (3) in four species of genus Arnebia (A. euchroma, A. guttata, A. benthamii, and A. hispidissima) from the Indian subcontinent has been developed. In addition, the effect of solvents with varying polarity (hexane, chloroform, ethyl acetate, and methanol) for the extraction of these compounds was studied. HPTLC was performed on precoated RP-18 F(254S )TLC plates. For achieving good separation, mobile phase consisting of ACN/methanol/5% formic acid in water (40:02:08 v/v/v) was used. The densitometric determination of shikonin derivatives was carried out at 520 nm in reflection/absorption mode. The method was validated in terms of linearity, accuracy, precision, robustness, and specificity. The calibration curves were linear in the range of 100-600 ng for shikonin and acetylshikonin, and 100-1800 ng for beta-acetoxyisovalerylshikonin. Lower LOD obtained for compounds 1-3 were 18, 15, and 12 ng, respectively, while the LOQ obtained were 60, 45, and 40 ng, respectively.

Metal-free activation of H2O2 by synergic effect of ionic liquid and microwave: chemoselective oxidation of benzylic alcohols to carbonyls and unexpected formation of anthraquinone in aqueous condition

H2O2 mediated oxidation of alcohols in ionic liquid is revisited, wherein, ionic liquids under the influence of microwave irradiation have been found to facilitate activation of H2O2 without any metal catalyst in aqueous condition. The method utilizes a neutral ionic liquid [hmim]Br both as catalyst and solvent for efficient and chemoselective oxidation of benzyl alcohol derivatives on aromatic (β, γ) alcohols, cyclic and aliphatic analogues, which can be a useful synthetic approach in total synthesis of complex organic compounds/natural products. Moreover, an unexpected oxidation of 9-anthracenyl propanol, a polyaromatic benzyl alcohol, resulting in the formation of 9,10-anthraquinone by the loss of propyl side chain was observed. Plausible mechanism and further exploration of this method on various other related substrates are discussed in detail.

Ultrafast UPLC‐ESI‐MS and HPLC with monolithic column for determination of principal flavor compounds in vanilla pods

In this study, two novel chromatographic methods based on monolithic column high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography (UPLC) were developed for the ultrafast determination of principal flavor compounds namely vanillin, vanillic acid, p-hydroxybenzoic acid, and p-hydroxybenzaldehyde in ethanolic extracts of Vanilla planifolia pods. Good separation was achieved within 2.5 min using Chromolith RP18e column (100 mm x 4.6 mm) for HPLC and Acquity BEH C-18 (100 mm x 2.1 mm, 1.7 microm) column for UPLC. Both methods were compared in terms of total analysis time, mobile phase consumption, sensitivity, and validation parameters like precision, accuracy, LOD, and LOQ. Further, system suitability test data including resolution, capacity factor, theoretical plates, and tailing factor was determined for both the methods by ten replicate injections. Monolithic column based HPLC gave better results for most of the selected parameters while UPLC was found to be more eco-friendly with low mobile phase consumption and better sensitivity. Both methods may be used conveniently for the high throughput analysis of large number of samples in comparison to traditional particulate column.