Soybean Callus—A Potential Source of Tocopherols

Liliana Mureșan,Doina Clapa,Teodor Rusu,Thomas T Y Wang,Jae B Park

doi:10.3390/plants10122571

Abstract

In vitro cultures have been used as an effective means to achieve a high level of secondary metabolites in various plants, including soy. In this study, the contents of α-, γ-, and δ- tocopherol were quantified in soybean callus, and their amounts were compared to those of soybeans cultivated using the conventional tillage system with three weed controls (respectively without herbicide and with two variants of herbicide). Soybean callus was produced using Murashige and Skoog 1962 (MS) medium supplemented with 0.1 mg/L 6-Benzylaminopurine (BAP) and 0. 1 mg/L Thidiazuron (TDZ). The highest amount of fresh callus was obtained from soybeans from the conventional tillage system with second weed control (S-metolachlor 960 g/L, imazamox 40 g/L, and propaquizafop 100 g/L) respectively 13,652.4 ± 1177.62 mg. The analyzed tocopherols were in much higher content in soy dry callus than the soybean seeds (5.63 µg/g compared with the 0.35 α-toco in soybean, 47.57 µg/g compared with 18.71 µg/g γ-toco or, 5.56 µg/g compared with 1.74 µg/g β-toco). The highest content of the three analyzed tocopherols was γ -tocopherol, both in callus and soybeans. Furthermore, the data showed that herbicides used in soybean culture significantly influenced both the in vitro callus production and the tocopherol callus content (p ˂ 0.05). Altogether, soybean callus can be an important source of tocopherols, and herbicides significantly influence in vitro callus production and the tocopherol callus content.

Highlights

Soybean (Glycine max (L.) Merr.) is a key species used by the nutraceutical and functional food industries for its secondary metabolites such as polyphenolic compounds, tocopherols, tannins, lignins, and alkaloids
The analyzed tocopherols were in much higher content in soy dry callus than the soybean seeds (5.63 μg/g compared with the 0.35 α-toco in soybean, 47.57 μg/g compared with 18.71 μg/g γ-toco or, 5.56 μg/g compared with 1.74 μg/g β-toco)
Γ-tocopherol was 81% in callus compared with 88% in soybean, α-tocopherol was 10% in callus compared with 2% in soybean, and δ-tocopherols was 9% in callus compared with 10% in soybean

Summary

Introduction

Soybean (Glycine max (L.) Merr.) is a key species used by the nutraceutical and functional food industries for its secondary metabolites such as polyphenolic compounds, tocopherols, tannins, lignins, and alkaloids. Soybean is an excellent source of tocopherols with about 300 μg g−1/seed total tocopherols [1]. Γ-tocopherol is found in higher concentrations (more than 60%), and α-tocopherol accounts for less than 10% of total tocopherols in soybean seeds [2]. As the α-tocopherol is an essential nutrient that functions as a peroxyl radical scavenger in the body, the dietary reference intake for vitamin E is currently based solely on α-tocopherol [3,4]. Αtocopherol is reported to have the most significant antioxidant activity among tocopherols and is preferred by the human body, as it is the predominant form of vitamin E found in the blood and tissues. Vitamin E is of vital importance for the nervous system, as a deficiency in humans leads to ataxia and myopathy [6]. α-tocopherol is found naturally in plant sources as RRR-a-tocopherol and synthetically manufactured as all-rac-a-tocopherol

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