Blog

Seaweed health benefits determination

In this article, you will discover the health benefits of seaweed through the use of Memmert laboratory vacuum oven working on lipid extracts.

A research article from 2020 used the Memmert vacuum oven VO to investigate the health benefits of seaweed. The full report can be read here. This article details key highlights and findings of the study which used the vacuum drying oven from Memmert’s heating and drying oven range.

Detailed information is now available in the vacuum oven whitepaper. Here you can download the whitepaper.

Interested to know what is a vacuum oven? Or what is a vacuum oven used for? All answers about the vacuum ovens, its features, purpose and applications are available in the Memmert blog, and in this expert interview.

This is an image of a seaweed fisherman at Inle Lake, Myanmar.

Seaweed fisherman at Inle Lake, Myanmar. Image licensed under the Creative Commons.

Background

Seaweed has a wide array of applications in food, fertilizers, phycocolloids, and cosmetic ingredients for nutraceuticals and pharmaceuticals. It is, however, considered underutilized as a resource.

Benefits of seaweed

The problem

The researchers have identified a key issue in the underutilization of seaweed. It is said that not enough work has been done to fully explore its application capacities.

...further work needs to be performed to identify the metabolites components of seaweed that are useful for industrial and pharmaceutical applications.

The objective

It is believed that a more holistic method is needed to confirm health benefits of seaweed through biochemical profiling.

  • Evaluate chemical compositions
  • Research α-glucosidase inhibitory and cytotoxic activities of extracts (types of seaweed used are U. intestinalis, H. macroloba, and S. ilicifolium) against five cancer cell lines including MCF-7 cells, MDA-MB-231 cells, HT-29 cells, Hep G2 cells, and 3T3 cells
  • Investigate for the commercial cultivation of edible seaweed as human food

Materials and methods

Preparation

Samples are collected from a place these are abundantly native to, in Malaysia, and cleaned.

This is an image of the 2 Seaweed sample S. ilicifolium that was worked on for its lipid content using a Memmert vacuum oven VO.
Seaweed sample S. ilicifolium. Courtesy of Hindawi.
This is a picture of aeaweed sample H. macroloba whose lipid content was investigated using a laboratory vacuum oven from Memmert.
Seaweed sample H. macroloba. Courtesy of Hindawi.
This is an image of Seaweed sample U. intestinalis that was part of an experiment to research its lipid content using a Memmert laboratory vacuum oven.
Seaweed sample U. intestinalis. Courtesy of Hindawi.

A portion was checked for taxonomic identification. Afterwards, the seaweed is once more washed, frozen overnight, lyophilized in a freeze dryer until constant biomass weight is achieved. Then, these freeze-dried samples are pulverized and sieved.

Finely prepared sample powder is mixed in methanol; this resulting solution is sonicated for an extraction. The solvent extract is filtered, and dried residue undergoes methanol mixing once more. The process repeats a third time. The extracts are dried in a rotary evaporator.

Determination of total carotenoids & chlorophyll contents with Memmert vacuum oven VO

Lipid extraction of seaweed samples take place: A portion of the freeze-dried powder is homogenized and filtered. The filtrate is mixed with sodium chloride and centrifuged at 2000rpm for 8min. Chloroform is collected and repeated rounds of solvent extraction is done to reach high lipid count.

A laboratory vacuum oven from Memmert, the VO, is used at this point. Concentrated lipid extracted that is collected is needed for this part.

  • The concentrated lipid extract is dried is placed in the vacuum oven
  • Oven temperature is maintained at 40°C
  • Process runs until constant weight is achieved
This is an image of the Memmert vacuum oven VO.

Memmert vacuum drying oven.

The newly dried lipid samples are stored. At this point, the total carotenoids and chlorophyll a and b contents of dried seaweed lipid extracts is measured. For exact figures, read the published study.

For detailed info on how the Memmert vacuum oven is best suited for applications and its benefits, reach out for a personal consultation.

α-Glucosidase Inhibition Assay

The researchers, at this point, determine the assay for a-glucosidase inhibition activity. ρ-Nitrophenyl-ρ-D-glucopyranoside (PNPG) substrate is used. Seaweed extracts are prepared, mixed in a 96-well microplate and incubated at room temperature for 5 minutes. 75μL of PNPG is added to wells consisting of sample, blank substrate, and negative/positive controls. Leftover wells are filled with 75μL of 30mM phosphate buffer. The wells are incubated for 15 minutes at room temperature. Reaction mixtures are applied with stopping agent. Absorbance is measured with a spectrophotometer set to 405nm. The resulting a-glucosidase inhibition activity is expressed as percentage (%) of inhibition.

Cells and culture conditions

The following are used:

  • MCF-7 cells (human breast adenocarcinoma cell line, estrogen receptor positive)
  • MDA-MB-231 cells (human breast adenocarcinoma cell line, estrogen receptor negative)
  • HT-29 cells (human colorectal adenocarcinoma cell line)
  • Hep G2 cells (human liver hepatocellular carcinoma cell line)
  • 3T3 cells (mouse embryonic fibroblast cells)

As for the condition, these cells were maintained for research purposes in RPMI medium which is supplemented with 10% fetal calf serum (FCS), 100 unit/ml penicillin, and 0.1mg/ml streptomycin.

MTT Assay Conditions

The sample extracts are tested for cytotoxicity levels. The extracts are tested on the above-mentioned cells. Protocol used in the anticancerous Effect of Typhonium flagelliforme on Human T4-Lymphoblastoid Cell Line CEM-ss research is used to determine the cytotoxicity using MTT assay. At the beginning, the cell culture was prepared (at a concentration of 1×105 cells/mL) and plated (100μL/well) into 96-well plates. Then incubation takes place, diluted ranges are dissolved in dimethyl sulfoxide (DMSO) and concentration of the DMSO is 0.1% (v/v).

Concentrations are plated as triplicate with untreated cell controls and blank cell-free control in each. A positive control was maintained as well. 68-hour incubation period followed, 20μL of MTT (5mg/mL) was added to individual wells to allow for formazan crystals formation and afterwards incubation took place to then remove the media later.

Diligent notes are made; the absorbance is recorded, percentage of cellular viability is noted, concentration which inhibited 50% of the cellular growth (IC50 value) is measured, inhibitory rate of cell proliferation is calculated, cytotoxicity of sample on cancer cells was expressed as IC50 values, and further, mycoplasma contamination tests on these samples resulted as negative.

Gas Chromatography-Mass Spectrometry Analysis

This part of the experimentation is carried out to characterize and quantify bioactive substances in the seaweed extracts. The study made use, with modifications, of course, of the method found in research surrounding the triterpene Glycosides from Sea Cucumber Holothuria leucospilota.

Findings

This is an image of a table showing the contents of carotenoids, chlorophyll a, and chlorophyll b from different species of seaweed.

The contents of carotenoids, chlorophyll a, and chlorophyll b from different species of seaweed. Courtesy of Hindawi.
This is an image of a table showing the IC50 value of the a-glucosidase activities of the methanolic extract of Halimeda macroloba, Ulva intestinalis, Sargassum ilicifolium, and quercetin in ppm unit.

The IC50 value of the a-glucosidase activities of the methanolic extract of Halimeda macroloba, Ulva intestinalis, Sargassum ilicifolium, and quercetin in ppm unit. Courtesy of Hindawi
This is an image of a table showing Potential cytotoxic activity of methalonic extracts of 3 seaweed species; U. intestinalis, H. macroloba, and S. ilicifolium on five different cell lines.

Potential cytotoxic activity of methalonic extracts of 3 seaweed species; U. intestinalis, H. macroloba, and S. ilicifolium on five different cell lines. Courtesy of Hindawi
This is an image of a table showing Cytotoxic activities of methanolic extract of H. macroloba at different concentrations (6.25–100 μg/ml against five different cancer cell lines in an MTT assay.

Cytotoxic activities of methanolic extract of H. macroloba at different concentrations (6.25–100 μg/ml against five different cancer cell lines in an MTT assay. Courtesy of Hindawi.
This is an image of a table showing Cytotoxic activities of methanolic extract of U. intestinalis at different concentrations (6.25–100 μg/ml against five different cancer cell lines in an MTT assay.

Cytotoxic activities of methanolic extract of S. ilicifolium at different concentrations (6.25–100 μg/ml against five different cancer cell lines in an MTT assay. Courtesy of Hindawi.
This is an image of a table showing cytotoxic activities of methanolic extract of S. ilicifolium at different concentrations (6.25–100 μg/ml against five different cancer cell lines in an MTT assay.

Cytotoxic activities of methanolic extract of U. intestinalis at different concentrations (6.25–100 μg/ml against five different cancer cell lines in an MTT assay. Courtesy of Hindawi.

 

For more information, read the data on the chemical composition of Ulva intestinalisHalimeda macroloba and Sargassum ilicifolium.

Takeaways

This study on U. intestinalis, H. macroloba, and S. ilicifolium seaweed have shown:

  • They can be good sources of bioactive, nutritionally and physiologically essential compounds
  • These compounds have opportunities for applications in nutraceuticals and pharmaceutical industries in the form of food and medicine
  • Seaweed pigments (total carotenoids, chlorophylls a and b) posses antidiabetic and anticancer potential

About Memmert vacuum oven

Memmert GmbH + Co.KG, operating out of Schwabach and manufacturing from Büchenbach, produces the vacuum oven VO as part of its diverse heating and drying oven range. 

It offers features such as:

  • Temperature range up to +200 °C
  • Vacuum control range: 5 to 1100 mbar
  • 3 model sizes (29 to 101 litres volume)
  • Anti-splinter; VDE-tested door construction for all models
  • Pump control: Optimised rinsing of the pump membrane as well as signal output for switching the pump ON/OFF according to requirements.
  • Optional: Pump base cabinet and energy-efficient vacuum pump
  • Nearly exclusive use of high-quality, rust-resistant and easy to clean stainless steel for interior and exterior housing
  • Precise and homogenous temperature control thanks to a product-specific heating concept
  • A wide range of options for programming and documentation using interfaces, integrated data loggers and the AtmoCONTROL software
  • 3 years guarantee worldwide

Read the blog for other vacuum oven application articles. Visit the homepage, or sign up for the newsletter, for more information on products such as climate chambers, incubators, laboratory water baths; medical devices such as sterilizers, blanket warmers and more. For detailed information, please send a message via email or inquiry form.