Tyrosinase Inhibitory Activity and Thermostability of the Flavonoid Complex from &lt;i&gt;Sophora japonica&lt;/i&gt; L (Fabaceae)

Js Lai,C Lin,Tm Chiang

doi:10.4314/tjpr.v13i2.12

Abstract

Purpose: To investigate the tyrosinase inhibitory activity and thermostability of weak acid-treated Sophora japonica L. flavonoid complex (SJ-FC) in different solutions.Methods: The flavonoid complex of S. japonica was isolated and treated with weak acid to generate SJ-FC. The anti-tyrosinase activities of SJ-FC and well-known tyrosinase inhibitors were compared by mushroom tyrosinase activity assay. The thermostabilities of SJ-FC and other inhibitors in differentsolution environments for long-term storage were also investigated.Results: The results indicate that SJ-FC has potent tyrosinase inhibitory activity, and at a concentration of 0.1 %, SJ-DC has a tyrosinase inhibitory activity equal to that of 1 % ascorbic acid or hydroquinone. In addition, SJ-FC in both propylene glycol (PG) and glycerol solutions exhibited obvious tyrosinase inhibitory activity. Ascorbic acid and arbutin, two other tyrosinase inhibitors, exhibit < 60 % of their initial activity in both PG and H2O solutions after 6 months of storage. However, SJ-FC stored in PG and H2O solutions retained almost 100 % of its activity over a 6-month period.Conclusion: SJ-FC is an effective and stable anti-tyrosinase agent and may be used as a function agent in medicines, foods and cosmetics.Keywords: Flavonoid, Sophora japonica L., Tyrosinase inhibitor, Thermostability

Highlights

The flowers and flower buds of Sophora japonicaL. (Fabaceae), widely cultivated in Asia, and referred to as Styphnolobium japonicum (L.)Schott., are famous traditional Chinese medicines [1]
The inhibition of S. japonica flavonoid complex (SJ-FC) at higher concentrations in both solutions did not differ significant, the results indicated that SJ-FC in propylene glycol (PG) has greater tyrosinase inhibitory
The results indicate that ascorbic acid decomposes in both PG and H2O solutions

Summary

Introduction

The flowers and flower buds of Sophora japonicaL. (Fabaceae), widely cultivated in Asia, and referred to as Styphnolobium japonicum (L.)Schott., are famous traditional Chinese medicines [1]. The flowers and flower buds of Sophora japonica. S. japonica has antioxidant [2,3], anti-inflammatory [4]. Anti-platelet activities [5] and can prevent weight gain in highfat diet-induced obese mice [6]. S. japonica reduces the damage caused by cerebral infarction, partly because of its antioxidant and anti-inflammatory activities [1,7]. Flavonoids are secondary metabolites in plants and are of interest to the pharmaceutical, nutritional and cosmetic industries because of their biological activities [8,9]. The primary components of S. japonica include flavones, tetraglycosides, isoflavones, isoflavone tetraglycosides, triterpene glycosides, phospholipids, alkaloids, amino acids and polysaccharides [10]. The major components of the flowers and flower buds of S

Results

Discussion

Conclusion