Antioxidant Potential and Cytotoxic Effect of Isoflavones Extract from Thai Fermented Soybean (Thua-Nao)

Abstract

Thua-nao, or Thai fermented soybeans, is a traditional Lanna fermented food in Northern Thailand. It is produced by using a specific bacterial species called Bacillus subtilis var. Thua-nao. We investigated the antioxidant activity and cytotoxic effect of isoflavones from Thua-nao. The phenolic compound contents and total flavonoid contents were determined by spectrophotometry. The antioxidant activity was examined using the ABTS, FRAP, and DPPH assays. The isoflavone contents and phenolic compositions were examined by the high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) techniques. The ability of isoflavones to inhibit human cancer cell growth was assessed by the MTT assay. The total phenolic content, total flavonoid content, and antioxidant activities of the isoflavones were 49.00 ± 0.51 mg GAE/g of dry extract (DE), 10.76 ± 0.82 mg QE/g of DE, 61.03 ± 0.97 µmol Trolox/g of DE, 66.54 ± 3.97 µM FeSO4/g of DE, and 22.47 ± 1.92% of DPPH inhibition, respectively. Additionally, the isoflavone extracts from Thua-nao had high isoflavone contents and polyphenolic compound compositions, especially daidzein and genistein. The isoflavone demonstrated a weak inhibition of MCF-7 and HEK293 cancer cell growth. It has a high antioxidant component, which is beneficial and can be developed for new therapeutic uses. However, further studies on the benefits of Thua-nao should be performed for realizing better and more effective uses soon.

Potential Properties of Natural Nutraceuticals and Antioxidants in Eye Protection

“…With this method of formulation two important limits could be avoided: the degrading action in the gastrointestinal system and the bioavailability of the compounds following digestion [249][250][251]. Second of all, the total antioxidant potential of the mixture should be calculated, which is not necessarily equal to the sum of that of the individual components [252][253][254]. Finally, specific toxicity experiments should be conducted in order to demonstrate that the mixture under consideration does not cause harm in any body district [255,256].…”

Nutritional, Phytochemical, and In Vitro Antioxidant Activity Analysis of Different States of Soy Products

“…Altogether, these findings summarized that FF in aqueous extract shows better antioxidant activity compared to other products. Interestingly, a previous study also described the in vitro antioxidant activity of soybean and soy products and also found that antioxidants from soybean can reduce free radicals in ABTS methods equivalent to Trolox [ 47 ]. Additionally, another study also found that the IC 50 of soybean was 77.9 mg and 5.5 mg per gram extract equivalent to gallic acid standard in DPPH and ABTS methods, respectively [ 48 ].…”

Modulation of redox-sensitive transcription factors with polyphenols as pathogenetically grounded approach in therapy of systemic inflammatory response

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