A high performance thin layer chromatography (HPTLC) method for the quality assessment of citronella oil: application in commercial sample analysis.

Citronella oil, extracted from Cymbopogon species (winterianus and nardus) is a commercially valuable essential oil used in personal-care products and insect repellents. Routine analysis in gas chromatography is incapable of detecting high-boiling adulterants therein. In this study, an HPTLC technique was developed for the absolute quantification of citronellal (characteristic chemical marker) and triglyceride (main constituent of vegetable oil adulterant) in citronella oil for its quality assessment. It was validated in terms of specificity, linearity, sensitivity, accuracy and precision. Further, the developed method was employed to quantify citronellal and triglyceride in twenty commercial samples. The results showed a wide variation in citronellal content (trace to 30.65% w/w) and could differentiate its two chemotypes. Also, it revealed the possibility of vegetable oil adulteration through the detection and quantification of triglyceride in selected samples. It can be a simple and rapid technique for the quality control of citronella oil.

A high performance thin layer chromatography (HPTLC) method for the quality assessment of agarwood (Aquilaria malaccensis) oil from Northeast India.

The high-value agarwood oil, largely used in perfumery is generally graded by the traditional method of sensorial assessment. The compositional complexity and variation made its quality control challenging. Besides, non-volatile contaminants and adulterants are the bottlenecks in gas-chromatographic detection. Herein, a HPTLC based technique was developed for the quality assessment of agarwood oil from Northeast India. A 'marker band' (anisylacetone and oxygenated sesquiterpene rich) on HPTLC profile, containing major peaks of the oil and characteristic agarwood aroma was quantified to assess the quality. The developed method was validated in terms of specificity, linearity, sensitivity, recovery and precision. The application of the method in test samples of three different grades indicated a positive correlation between 'marker band' quantity and oil quality. Its abundance in the superior grade oil was >50% and <20% in poor grade. It can be an efficient analytical tool for the quality assessment and grading of agarwood oil.

Effect of natural gas flaring upon the butterfly, Eurema hecabe (Lepidoptera: Pieridae) and its host plant, Cassia tora (Fabales: Fabaceae) in two group gathering stations of Assam, India: an approach of environmental monitoring.

Apart from other pollutants, flaring of natural gas adds carbon dioxide into the environment and changes the atmospheric composition, including temperature and humidity. As a major gaseous product, carbon dioxide changes plant structural components as well as herbivores, i.e., insect by dilution of nitrogen under such circumstances. Present analysis demonstrated the impact of gas flaring upon adjoining biota especially Eurema hecabe butterfly and its host plant, Cassia tora in some wells (group gathering stations) of Assam, India. Analysis, pertaining from the current investigation, documented higher carbon dioxide as well as temperature in the studied flaring sites. Apart from this, reduction of leaf nitrogen, SLA, and chlorophyll with increasing in LDMC, thickness, and carbon in the studied plant as well as poor developmental rate, RGR, ECD with high RCR in insect indicated severe impact of flaring in those areas. Simulation studies with different concentration of CO2 in open top chamber on the plant and butterfly also revealed similar trend of results.

Chaetanaphothrips kiyosumianus (Thysanoptera, Thripidae) new to India with first record of the male.

The male of Chaetanaphothrips kiyosumianus Kudô is diagnosed for the first time along with the first record of this species from India. Molecular data of mitochondrial cytochrome c oxidase (mtCOI) from specimens of this species are also generated as additional data for future studies.

A carbazole alkaloid deactivates mTOR through the suppression of rictor and that induces apoptosis in lung cancer cells.

Non-small cell lung cancer (NSCLC) is known to be a difficult cancer to treat because of its poor prognosis, limited option for surgery, and resistance to chemo or radiotherapy. In this study, we have demonstrated that suppression of rictor expression in A549 and H1299 NSCLC cells by mahanine, a carbazole alkaloid, disrupted constitutive activation of mTOR and Akt. Mahanine suppression of rictor gene expression and consequent attenuation of its protein expression affected the inhibition of mTOR (Ser-2481) and Akt (Ser-473) phosphorylation. Since mahanine treatment revealed this new insight of rictor-mTOR relationship, we examined an association between mTOR activation with rictor expression. Interestingly, in rictor knockdown (KD) NSCLC cells, mTOR activation was significantly impaired. Transfection of rictor over-expression vector into the NSCLC cells reversed this situation. In fact, both rictor KD and mahanine treated cells showed considerably depleted phospho-mTOR level. These results indicate that rictor is required to maintain constitutive activation of mTOR in lung cancer cells. When mTOR kinase activity in rictor KD cells was examined with Akt as substrate, a significant reduction of Akt phosphorylation indicated impairment of mTOR kinase potentiality. Disruption of mTOR and Akt activation caused drastic mortality of NSCLC cancer cells through apoptosis. Hence, our study reveals a new dimension in mTOR-rictor relationship, where rictor stands to be a suitable therapeutic target for lung cancer.

Morphological and genetic diversity studies among populations of tea mosquito bug, Helopeltis theivora from Assam, India.

Multilocus DNA fingerprinting and morphometry were compared to evaluate genetic diversity of tea mosquito bug, Helopeltis theivora Waterhouse (Hemiptera: Miridae). Eighty-one female individuals representing 27 populations of H. theivora from tea plantations of different regions of Assam, India were collected and evaluated. Observation of 12 characters i.e. body length, antennae length, head width, stylet length, thorax width, forewing length, forewing width, hind wing length, hind wing width and length of foreleg, middle leg, hind leg revealed distinct pattern in different population of H. theivora. On the basis of morphological traits, six different types of population groups have been identified. Genetic analysis produced a total number of 262 bands, of which 221 (84.35 %) were polymorphic. The number of bands produced per primer varied from 2 to 17. The dendrogram derived from UPGMA cluster analysis indicates three clusters containing 24 populations at 63 % of similarity while three populations viz. H23, H19 and H14 excluded from the major cluster and come out as a discrete cluster. The cluster 1 includes populations from 9 different districts of Assam, cluster 2 again included 5 populations, cluster 3 constitute 3 populations and cluster 4 again consist of 3 populations. Both marker (morphological and molecular) systems indicated that genetic variability within populations examined was significantly high. Appropriate quality and quantity of chemical pesticides used in pest control programmes is a fundamental goal in the tea industry. It is supported by the knowledge of patterns of population connectivity and historical demography.

Vapor of volatile oils from Litsea cubeba seed induces apoptosis and causes cell cycle arrest in lung cancer cells.

Non-small cell lung carcinoma (NSCLC) is a major killer in cancer related human death. Its therapeutic intervention requires superior efficient molecule(s) as it often becomes resistant to present chemotherapy options. Here we report that vapor of volatile oil compounds obtained from Litsea cubeba seeds killed human NSCLC cells, A549, through the induction of apoptosis and cell cycle arrest. Vapor generated from the combined oils (VCO) deactivated Akt, a key player in cancer cell survival and proliferation. Interestingly VCO dephosphorylated Akt at both Ser(473) and Thr(308); through the suppression of mTOR and pPDK1 respectively. As a consequence of this, diminished phosphorylation of Bad occurred along with the decreased Bcl-xL expression. This subsequently enhanced Bax levels permitting the release of mitochondrial cytochrome c into the cytosol which concomitantly activated caspase 9 and caspase 3 resulting apoptotic cell death. Impairment of Akt activation by VCO also deactivated Mdm2 that effected overexpression of p53 which in turn upregulated p21 expression. This causes enhanced p21 binding to cyclin D1 that halted G1 to S phase progression. Taken together, VCO produces two prong effects on lung cancer cells, it induces apoptosis and blocked cancer cell proliferation, both occurred due to the deactivation of Akt. In addition, it has another crucial advantage: VCO could be directly delivered to lung cancer tissue through inhalation.

Insect pests of tea and their management.

Globally, 1031 species of arthropods are associated with the intensively managed tea Camellia sinensis (L.) O. Kuntze monoculture. All parts of the plant, leaf, stem, root, flower, and seed, are fed upon by at least one pest species, resulting in an 11%-55% loss in yield if left unchecked. There has been heavy use of organosynthetic pesticides since the 1950s to defend the plant against these pests, leading to rapid conversion of innocuous species into pests, development of resistance, and undesirable pesticide residues in made tea. As a result of importer and consumer concerns, pesticide residues have become a major problem for the tea industry. Integrated pest management (IPM) may help to overcome the overuse of pesticides and subsequent residues. We review the advances made in our understanding of the biology and ecology of major insect and mite pests of tea, host plant resistance, cultural practices, biocontrol measures, and need-based application of botanicals and safer pesticides to understand the present status of IPM and to identify future challenges to improvement.