Modificações químicas de polissacarídeos das algas Lobophora variegata e Dictyota mertensii potencializam suas atividades farmacológicas
Laminarin (1,3-β-glucan) and fucan (sulfated polysaccharide consisting of sulfated Lfucose) are synthesized by brown seaweeds and have several pharmacological activities described. However, polysaccharides and their activities can be modified, increasing their activities. Thereunto, various techni...
সংরক্ষণ করুন:
| প্রধান লেখক: | |
|---|---|
| অন্যান্য লেখক: | |
| বিন্যাস: | doctoralThesis |
| ভাষা: | pt_BR |
| প্রকাশিত: |
Brasil
|
| বিষয়গুলি: | |
| অনলাইন ব্যবহার করুন: | https://repositorio.ufrn.br/jspui/handle/123456789/28102 |
| ট্যাগগুলো: |
ট্যাগ যুক্ত করুন
কোনো ট্যাগ নেই, প্রথমজন হিসাবে ট্যাগ করুন!
|
| সংক্ষিপ্ত: | Laminarin (1,3-β-glucan) and fucan (sulfated polysaccharide consisting of sulfated Lfucose) are synthesized by brown seaweeds and have several pharmacological
activities described. However, polysaccharides and their activities can be modified,
increasing their activities. Thereunto, various techniques are used, such as those
called green methods. Given the above, and bearing in mind that the potiguar coast,
as well as the northeastern, holds several species of seaweed that have not had their
neutral and sulfated polysaccharides completely studied, this work aimed to prospect
the main chemical modifications in neutral polysaccharides (laminarins) from
Lobophora variegata and sulfated polyscarides (fucanas) from Dicytiota mertensii
and verify their farmacological activities, choosing the best modifications for structural
characterization. Algae were collected at Pirangi beach, Natal, RN, washed and
submitted to proteolysis. Using acetone differential fractionation and molecular mass
separation techniques, a 12.4 kDa laminarin was obtained. Physicochemical analysis
showed that laminarin (LM) consists only of glucose. Dielectric barrier discharge
(DBD), sulfation and galification techniques were used to obtain modified laminarins
called LMC, LMS and LMG. The modifications promoted different amounts functional
groups inserted: for LMS 1.4% of sulfate was observed, for LMG 1.5% of gallic acid
and LMC 11.7% of uronic acids. The modification that most enhanced the antioxidant
activities of laminarins was galification, therefore, LM and LMG had their structure
elucidated by Nuclear Magnetic Resonance (NMR). The data obtained by NMR
analysis corroborate with the previous data proving the structure of laminarin in LM
and gallified laminarin in LMG. LM and LMG were not cytotoxic and did not alter the
cell cycle of normal canine kidney cells (MDCK) compared to the control. In parallel, it
was possible to obtain fucans from D. mertensii after proteolysis and precipitation
with methanol. Therefore, silver nanoparticles with fucan called NF were synthesized
and called NF. The seventh day was the optimal synthesis day for this particle,
whose size was approximately 104 nm. The NF had a round shape very
homogeneous size distribution, and stability for 16 months and showed a higher
antitumor activity (1mg / mL) compared to fucan. NF also had better antibacterial
activity than native fucan and immunomodulatory activities (nitric oxide production
and cytokine production) had similar results when compared to NF with native
fucans. In general, it we observed that the gallification was the best chemical modification in L. variegata laminarins and the NF potentiated the pharmacological
activities of the fucans. |
|---|