Antifeedant neo-clerodanes from Teucrium tomentosum Heyne. (Labiatae)

Kumari, G. N. Krishna; Sivasubramanian, Aravind; Balachandran, Jaya; Ganesh, Munuswamy Ramanujam; Devi, S. Soundarya; Rajan, S. S.; Malathi, R.; Ravikumar, K.

doi:10.1016/s0031-9422(03)00510-7

Cited by 38 publications

(6 citation statements)

References 17 publications

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“…Moreover, based on the cross-peaks from H-19 a ( δ H 4.84) to H-7 ax ( δ H 1.86), and from H-19 b ( δ H 4.77) to H-1 ax ( δ H 1.42)/H-3 ax ( δ H 2.21), the C-19/C-20 γ -lactone moiety was positioned on the alpha face of the decalin ring [49][50][51] . The absolute configurations in 15 were established by single-crystal X-ray crystallography, which also indicated two independent molecules in the asymmetric unit of 15 ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Mechanisms of cellular resistance to imatinib in human chronic myeloid leukemia cells

2007

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A major advancement in the treatment of chronic myeloid leukemia (CML) has been the development of imatinib, which has shown striking activity in the chronic phase and the accelerated phase, but less so in the blast phase of the disease. Despite high rates of hematologic and cytogenetic responses to therapy, the emergence of resistance to imatinib has been recognized as a major problem in the treatment of patients with CML. Various cellular mechanisms may be involved in the nature of cellular resistance. Increased amount of target, alteration in structure of target proteins, decreased drug uptake and increased detoxification are well-known mechanisms of resistance. On the other hand, in some cases, even if anticancer drugs reach their sites of action, bypassing drug efflux system of the cells, some cells still may survive via the dysregulation of apoptotic signalling. In this study, mechanisms of resistance to imatinib-induced apoptosis in human Meg-01 CML cells were examined. Continuous exposure of cells to step-wise increasing concentrations of imatinib resulted in the selection of 200- and 1000 nM imatinib-resistant sub-lines referred to as Meg-01/IMA-0,2 and Meg-01/IMA-1, respectively. MTT cell proliferation, cell cycle analyses and trypan blue dye exclusion analyses showed that Meg-01/IMA-1 cells were resistant to imatinib-induced apoptosis as compared to parental sensitive cells. There was an increased expression of BCR/ABL, Bcl-2 and an increase in mitochondrial membrane potential (MMP) detected in resistant cells comparing to parental sensitive cells. There was no mutation detected in imatinib binding site of ABL kinase region. Various diverse mechanisms have been reported for their involvement in the multidrug resistance. In this study, it has been shown that the degree of BCR/ABL expression appears to be directly proportional to the levels of imatinib resistance. In addition, there have been BCR/ABL-independent mechanisms reported for deriving resistance against imatinib. Our results revealed that besides BCR/ABL overexpression, imatinib resistance also depends on the inhibition of apoptosis as a result of up-regulation of anti-apoptotic stimuli and down-regulation of pro-apoptotic stimuli through MMP but does not depend on any mutation on imatinib binding site of ABL kinase.

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Section: Resultsmentioning

confidence: 99%

Mechanisms of cellular resistance to imatinib in human chronic myeloid leukemia cells

2007

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“…For different plant materials, various effects such as antifeedant activities, growth inhibition, and insecticidal activities have been reported (Giordano et al 2001; Krishna et al 2003 ; Nishida et al 2004 ; Gonzalez-Coloma et al 2005 ). Although the phytochemicals of C. infortunatum had a high antifeedant activity against H. armigera , when these compounds were applied topically on 3 rd instar larvae of H. armigera , very low mortality was observed compared to the control larvae.…”

Section: Discussionmentioning

confidence: 99%

Insecticidal and antifeedant activities of clerodane diterpenoids isolated from the Indian bhant tree, Clerodendron infortunatum, against the cotton bollworm, Helicoverpa armigera

Abbaszadeh

Srivastava

Walia

2014

Journal of Insect Science

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The Indian bhant tree, Clerodendron infortunatum L. (Lamialus: Lamiaceae), is a well-known medicinal plant, but little information about its bioefficacy against agricultural pests exists. This scarcity was addressed in the present study, in which dried leaves of C. infortunatum were subjected to extraction with hexane and methanol and then partitioned using different solvents of varying polarity. In a preliminary bioassay, the antifeedant effects of the crude extracts and fractions were tested on a highly polyphagous pest, the cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), using the no-choice test method with cabbage leaf discs. The methanol fraction resulted in maximum antifeedant activity. This fraction was further subjected to crystallization and column chromatography in order to isolate the compounds responsible for the activity. Three pure compounds were isolated and identified as clerodin (CL), 15-methoxy-14, 15-dihydroclerodin (MD), and 15-hydroxy-14, 15-dihyroclerodin (HD). The antifeedant activity of these compounds was studied using a choice as well as a no-choice test method with 24 and 48 hr observation periods. Insecticidal activity was measured using the topical application method at 0.5, 1, 1.5, 2, 2.5, and 3% concentrations, and data were recorded 24, 48, and 72 hr after treatment. In the no-choice test conditions, compounds CL and MD showed significantly higher antifeedant activity compared to the key ingredient in many commercial pesticides, azadirachtin, at its highest concentration. Compound HD also showed very good antifeedant activity, which did not differ significantly from that of azadirachtin. In the choice test conditions, all three compounds and azadirachtin showed 100% antifeedant activity at the highest concentration. Antifeedant Index (AI50) values of CL, MD, and HD were 6, 6, and 8 ppm in choice tests, and increased to 8, 9, and 11 ppm in the no-choice tests, respectively. Insecticidal activity of the isolated compounds was not significant compared to the control condition, even at the highest con-concentrations of the compounds. These results suggest that extracts of C. infortunatum have very good antifeedant effects against H. armigera due to the presence of specific compounds. These compounds could be utilized in the development of new biopesticides.

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“…[10] Folk medicine indicates that a decoction of T. massiliense aerial parts was used as a febrifuge and antimalaric effect. [10,11,13] The occurrence of some pharmacologically active compounds in T. massiliense extracts have been reported, especially, neoclerodane diterpenoids [14,15] were reported as insect antifeedants [16,17] and antifungal, antimicrobial and moluscicidal agents. [18,19] To the best of our knowledge, only one study reported the chemical composition and antioxidant activity of T. massiliense essential oil from Sardinia.…”

Section: Introductionmentioning

confidence: 99%

Qualitative and quantitative analysis of volatile components of Teucrium massiliense L. – identification of 6‐methyl‐3‐heptyl acetate as a new natural product

Djabou¹,

Paolini²,

Desjobert³

et al. 2010

Flavour & Fragrance J

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Volatile components extracted from the aerial parts and separated organs of Corsican and Sardinian Teucrium massiliense have been studied. The chemical composition of essential oils obtained by hydrodistillation (HD) has been investigated using GC-RI, GC-MS (EI and CI modes) and 13 CNMR spectroscopy. For the first time, a real concentration via calibration curves and response factor calculations has been determined for each oil component. The concentrations of the major components were 6-methyl-3-heptyl acetate (23.83-18.16 g/100 g), 3-octyl acetate (10.55-6.95 g/100 g), isobutyl isovalerate (7.67-2.91 g/100 g), germacrene D (6.13-1.01 g/100 g) and linalool (6.63-5.23 g/100 g). To the best of our knowledge, the occurrence of 6-methyl-3-heptyl acetate as a natural product is reported for the first time. Furthermore, the chemical composition of volatile fractions emitted from the aerial parts and separated organs of T. massiliense L. has been studied by HS-SPME/ GC-RI and GC-MS after optimization of SPME parameters. Concerning the contribution of plant organs to the aromatic plant fingerprint, we noted that the flowers produced more volatiles than other organs. The volatile fractions obtained from the different organs were qualitatively quite similar to each other but differed in the percentages of their major components. Also, the influence of HS-SPME extraction parameters (equilibrium and extraction times and temperature) on the chemical composition of the plant volatile fraction is discussed.

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Antifeedant neo-clerodanes from Teucrium tomentosum Heyne. (Labiatae)

Cited by 38 publications

References 17 publications

Mechanisms of cellular resistance to imatinib in human chronic myeloid leukemia cells

Mechanisms of cellular resistance to imatinib in human chronic myeloid leukemia cells

Insecticidal and antifeedant activities of clerodane diterpenoids isolated from the Indian bhant tree, Clerodendron infortunatum, against the cotton bollworm, Helicoverpa armigera

Qualitative and quantitative analysis of volatile components of Teucrium massiliense L. – identification of 6‐methyl‐3‐heptyl acetate as a new natural product

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