Optimized extraction of sulfated polysaccharide from brown seaweed Sargassum polycystum and its evaluation for anti-cancer and wound healing potential

https://doi.org/10.1016/j.sajb.2022.03.015Get rights and content

Highlights

  • Optimized acidic hot water extraction of WSCSPs.

  • WSCSPs exhibit antioxidant property.

  • WSCSPs promote wound healing in RAW 264.7 cells.

  • WSCSPs is not cytotoxic to normal L6 myoblast cells.

  • WSCSPs induce death of HeLa cancer cells.

Abstract

In the present study, we optimized the extraction of water-soluble crude sulfated polysaccharide (WSCSP) from Sargassum polycystum and its biological activity was investigated. The WSCSP was extracted from S. polycystum by the acidic water extraction method. The Box-Behnken experimental design was used as a tool for the extraction and evaluated in variable conditions extraction temperature as 60 °C, extraction time duration as 60 min, pH 5.0 and acid hot water: algal ratio 1:50 (g/ml) on these conditions, respectively. The use of acid hot water extraction was efficient to obtain a high WSCSP yield (59.80 ± 2.52%) and further characterization and morphology were analyzed by Fourier-transform infrared spectroscopy (FTIR), Nuclear magnetic resonance spectroscopy (NMR), Thermogravimetry analysis (TGA), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and the dynamic light scattering (DLS). WSCSP was shown to possess antioxidant activity, as evident by the DPPH assay. Moreover, WSCSP did not induce any significant cytotoxicity in L6 myoblast normal cell line. WSCSP also triggers wound healing in RAW 264.7 cells. WSCSP also induces significant death of HeLa (cervical cancer) cells, marking its cancer specificity. Hence WSCSP derived from Sargassum polycystum can be used as an anticancer candidate in future.

Introduction

Cancer is uncontrolled cell proliferation, leading to metastasis in later stages (Bray et al., 2018; Jemal et al., 2007). Of various cancer types, Cervical cancer (carcinoma of the uterine cervix) is a significant health issue faced by women, and every year, approximately 120,000 women develop this disease. Cervical cancer is the fourth most frequent cancer in women, with an estimated 570,000 new cases in 2018 representing 6.6% of all female cancers. Approximately 90% of deaths from cervical cancer occur in middle-income countries (Ferlay et al., 2019). Despite the availability of many chemotherapeutics in practice for cervical cancer, their harmful side effects pose a serious problem. Hence the quest for phytotherapeutics with anticancer effects and minimal aftereffects has been booming nowadays.

India is a land with significant biodiversity, which is recognized as a rich source of functionally novel and potentially active biometabolites in its marine ecosystem. The marine algae comprise approximately 20,000 red, brown and green algae (Vanavil et al., 2020). These marine algae are potential sources of bioactive compounds such as polyphenols, carotenoids, vitamins, phycobilins, phycocyanins and their derivatives, including sulfate, phosphate and polysaccharides. These constituents exhibit anti-adhesive, antioxidant, antiviral, antitumor, antiulcerogenic, antithrombotic, anticoagulant and anti-proliferative activities (Mansur, 2020; Motshakeri et al., 2013; Sinurat et al., 2016).

Studies have shown Fucoidans possess antitumor effects through activating cellular apoptosis, inhibiting tumor metastasis and potentiating the toxic effect of chemical drugs. Ascophyllum sp., Fucus spp., Laminaria spp. and Sargassum spp. were commonly used in biotechnological aspects. Sulfated polysaccharides obtained from Sargassum sp. were considered as a potential natural resource (Gomaa et al., 2018; Hifney et al., 2016; Ly et al., 2005). However, Sargassum polycystum is a less exploited genus despite it growing wildly in enormous quantities almost all over the world. Hence

In the present study, S. polycystum was selected as the botanical source of sulfated polysaccharides. Extraction of sulfated polysaccharides can be done with acid treatment, which greatly influences the extracted polysaccharides' yield and physicochemical properties (Vauchel et al., 2008). Recently, response surface methodology (RSM) was applied to optimize the extraction temperature, acid concentration, and solvent consumption in the polysaccharide yield response (Mazumder et al., 2016). However, to receive a higher yield and maintain the physico-chemical properties of crude polysaccharide, an optimization study is required to determine various factors' influence and inpolysaccharidesnce. The study was designed as an optimization study for the extraction of sulfated polysaccharides from S. polycystum. Evaluation of antioxidant and anti-carcinogenic potential of these extracted sulfated polysaccharides WSCSP were analyzed using HeLa cell line. Cytotoxicity of WSCSP was assessed using a normal L6 myoblast cell line.

Section snippets

Collection and identification

The seaweeds of Sargassum polycystum were collected from the Mandapam coastal region, Gulf of Mannar (9°16′54.5″N 79°11′16.9″E) Rameshwaram, Tamil Nadu, India. After collection, the seaweeds were washed with seawater, followed by washing with distilled water to remove the debris and shade dried at room temperature. The dried seaweeds were cut into small pieces and powdered for extraction.

Extraction of WSCSP

The extraction of water-soluble crude sulphated polysaccharides (WSCSP) was performed as described (

BBD-Optimization by RSM

The RSM-BBD design was adopted to extract water-soluble crude polysaccharide (WSCSP) of S. polycystum. It was carried out with three different extraction protocols: extraction with acid water, alkaline water, and neutral water. In Table 2, the detailed experimental design and selected variables for the optimization of the study.

To examine the combinatorial extraction method variables (A: buffer to algae ratio, B: time duration, C: extraction temperature, D: pH) on the WSCSP extraction by

Conclusion

In conclusion, we demonstrated the optimization of WSCSP extraction from S. polycystum. BBD-RSM design was utilized to upgrade the extraction conditions by acidic high hot water extraction. The optimum conditions were acidic water to an algal ratio of 1:50 g/dl, extraction time for 60 min and extraction temperature at 60℃ under these conditions, the extraction yield of WSCSP 59.8 ± 0.75% agreed with the predictive value of 59.8 ± 2.52%. Correspondingly, the WSCSP exhibits the potential of

Declaration of competing interest

None.

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