Effects of Carboxymethyl Modification on the Acidic Polysaccharides from Calocybe indica: Physicochemical Properties, Antioxidant, Antitumor and Anticoagulant Activities

Ambika Nataraj; Sudha Govindan; Archana Rajendran; Prasanna Ramani; Krishnamoorthy Akkana Subbaiah; Paulo E S Munekata; Mirian Pateiro; José M Lorenzo

doi:10.3390/antiox12010105

Effects of Carboxymethyl Modification on the Acidic Polysaccharides from Calocybe indica: Physicochemical Properties, Antioxidant, Antitumor and Anticoagulant Activities

Antioxidants (Basel). 2022 Dec 31;12(1):105. doi: 10.3390/antiox12010105.

Authors

Ambika Nataraj¹, Sudha Govindan¹, Archana Rajendran^{2

3}, Prasanna Ramani^{2

3}, Krishnamoorthy Akkana Subbaiah⁴, Paulo E S Munekata⁵, Mirian Pateiro⁵, José M Lorenzo^{5

6}

Affiliations

¹ Department of Biochemistry, School of Biosciences, Periyar University, Salem 636001, India.
² Dhanvanthri Laboratory, Department of Sciences, Amrita School of Physical Sciences, Amrita Vishwa Vidyapeetham, Coimbatore 641112, India.
³ Center of Excellence in Advanced Materials & Green Technologies (CoE-AMGT), Amrita School of Engineering, Amrita Vishwa Vidyapeetham, Coimbatore 641112, India.
⁴ Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore 641003, India.
⁵ Centro Tecnológico de la Carne de Galicia, Avd. Galicia No. 4, Parque Tecnológico de Galicia, 32900 San Cibrao das Viñas, Spain.
⁶ Área de Tecnoloxía dos Alimentos, Facultade de Ciencias, Universidade de Vigo, 32004 Ourense, Spain.

Abstract

An acidic polysaccharide fraction was obtained from Calocybe indica (CIP3a) after subjecting it to hot water extraction followed by purification through DEAE-cellulose 52 and Sepaharose 6B column chromatography. The CIP3a was further modified using chloroacetic acid to yield carboxymethylated derivatives (CMCIP3a). The modified polysaccharide was characterized using various spectroscopic methods. In addition, further antioxidant, antitumor and anticoagulant activities were also investigated. The polysaccharides CIP3a and CMCIP3a were heterogeneous in nature and composed of various molar percentages of glucose, arabinose and mannose with molecular weights of 1.456 × 10³ and 4.023 × 10³ Da, respectively. The NMR and FT-IR data demonstrated that the carboxymethylation on the polysaccharide was successful. In comparison to CIP3a polysaccharides, the modified derivatives had lower sugar and protein contents, and higher levels of uronic acid. The in vitro antioxidant activity showed that CMCIP3a with higher molecular weight displayed an elevated ability in scavenging the DPPH radical, ABTS, superoxide, hydroxyl radical, ferric reducing power, cupric reducing power and erythrocyte hemolysis inhibition with an EC₅₀ value of 2.49, 2.66, 4.10, 1.60, 3.48, 1.41 and 2.30 mg/mL, respectively. The MTT assay results revealed that CMCIP3a displayed a dose-dependent inhibition on five cancer cells (HT29, PC3, HeLa, Jurkat and HepG-2) in the range of 10-320 μg/mL. The APTT, PT and TT were significantly extended by CMCIP3a in relation to dosage, indicating that the anticoagulant effect of CIP was both extrinsic and intrinsic, along with a common coagulation pathway. These findings demonstrated that carboxymethylation might effectively improve the biological potential of the derivatives and offer a theoretical framework for the creation of novel natural antioxidants, low-toxicity antitumor and antithrombotic drugs.

Keywords: Calocybe indica; anticoagulation activity; antioxidant activity; antitumor activity; carboxymethylation; polysaccharides.

Grants and funding

This research received no external funding.