4 research outputs found
Regional variation in the composition and structure of mixed-species bird flocks in the Western Ghats and Sri Lanka
Mixed-species bird flocks are attractive models for the
investigation of geographical variation in animal communities,
as they represent a subset of the avifauna in
most forested regions of the world. Yet studies of the
regional variation in flock size and the composition of
flocks are few, due to the predominance of studies
carried out at single study site. Here, we review nine
studies of mixed-species flocks conducted at 16 sites
along the Western Ghats in India and in Sri Lanka.
We find that flock size varies as much within this
region as it does globally, with observation time being
a confounding variable. Flock composition, however,
is predictably related to elevation. Flocks at high elevations
(>1200 m) in the Western Ghats strongly resemble
flocks at high elevations in the mountain
ranges of Sri Lanka in their composition, especially at
the family level. We compare these flocks to flocks of
other regions and make recommendations on study
methodology that can facilitate comparisons across
studies
Regional variation in the composition and structure of mixed-species bird flocks in the Western Ghats and Sri Lanka
Mixed-species bird flocks are attractive models for the investigation of geographical variation in animal communities, as they represent a subset of the avifauna in most forested regions of the world. Yet studies of the regional variation in flock size and the composition of flocks are few, due to the predominance of studies carried out at single study site. Here, we review nine studies of mixed-species flocks conducted at 16 sites along the Western Ghats in India and in Sri Lanka. We find that flock size varies as much within this region as it does globally, with observation time being a confounding variable. Flock composition, however, is predictably related to elevation. Flocks at high elevations (>1200 m) in the Western Ghats strongly resemble flocks at high elevations in the mountain ranges of Sri Lanka in their composition, especially at the family level. We compare these flocks to flocks of other regions and make recommendations on study methodology that can facilitate comparisons across studies
Design, synthesis and cytotoxic effects of curcuminoids on HeLa, K562, MCF-7 and MDA-MB-231 cancer cell lines
Background
Curcumin is one of the leading compound extracted from the dry powder of Curcuma longa (Zingiberaceae family), which possess several pharmacological properties. However, in vivo administration exhibited limited applications in cancer therapies.
Results
Twenty-four curcumin derivatives have synthesized, which comprises cyclohexanone 1–10, acetone 11–17 and cyclopentanone 18–24 series. All the curcuminoids were synthesized by the acid or base catalyzed Claisen Schmidt condenstion reactions, in which β-diketone moiety of curcumin was modified with mono-ketone. These curcuminoids 1–24 were screened against HeLa, K562, MCF-7 (an estrogen-dependent) and MDA-MB-231 (an estrogen-independent) cancer cell lines. Among them, acetone series 11–17 were found to be more selective and potential cytotoxic agents. The compound 14 was exhibited (IC50 = 3.02 ± 1.20 and 1.52 ± 0.60 µg/mL) against MCF-7 and MDA-MB-231 breast cancer cell lines. Among the cyclohexanone series, the compound 4 exhibited (IC50 = 11.04 ± 2.80, 6.50 ± 01.80, 8.70 ± 3.10 and 2.30 ± 1.60 µg/mL) potential cytotoxicity against four proposed cancer cell lines, respectively. All the curcucminoids were characterized with the detailed 1H NMR, IR, UV–Vis, and mass spectroscopic techniques. The structure of compound 4 was confirmed by using the single X-ray crystallography. Additionally, we are going to report the first time spectral data of (2E,6E)-2,6-bis(2-methoxybenzylidene)cyclohexanone (1). Structure–activity relationships revealed that the mono-carbonyl with 2,5-dimethoxy substituted curcuminoids could be an essential for the future drugs against cancer diseases.
Conclusions
Curcuminoids with diferuloyl(4-hydroxy-3-methoxycinnamoyl) moiety with mono carbonyl exhibiting potential cytotoxic properties. The compound 14 was exhibited (IC50 = 3.02 ± 1.20 and 1.52 ± 0.60 µg/mL) against MCF-7 and MDA-MB-231 breast cancer cell lines