Effects of Microbial Transformation on the Biological Activities of Prenylated Chalcones from Angelica keiskei.

Yina Xiao,Ik-Soo Lee

doi:10.3390/foods11040543

Abstract

Microbial transformation is an alternative method for structural modification. The current study aimed at application of microbial transformation for discovering new derivatives and investigating the structure-activity relationship of isobavachalcone (1), 4-hydroxyderricin (2), and xanthoangelol (3) isolated from the herb Angelica keiskei. In the initial screening process, 1–3 were incubated with microbes using a two-stage fermentation method and analyzed through TLC monitoring. The screening results showed that Rhizopus oryzae and Mucor hiemalis were able to transform 1 and 2, respectively. Additionally, M. hiemalis and Mortierella ramanniana var. angulispora were able to transform 3. Following scale-up fermentation, four new (4, 5, 7, and 10) and five known (6, 8, 9, 11, and 12) metabolites were produced. Cytotoxicity of all the compounds (1–12) was investigated using three human cancer cell lines including A375P, HT-29, and MCF-7 by MTT method. Meanwhile, the tyrosinase inhibitory activity of 1–12 was evaluated using l-tyrosine as a substrate. Overall, 1 and 3 displayed the highest cytotoxicity, and 5 and 7 exhibited the most potent tyrosinase inhibitory activity with relatively low cytotoxicity. This allowed us to postulate that the introduction of 4′-O-glucopyranosyl group led to the reduction in cytotoxicity and improvement in tyrosinase inhibitory activity.

Highlights

Angelica keiskei (Umbelliferae) is a perennial leafy herb, mainly distributed in Asian countries, including Korea and Japan
Another prevalent name in Korean for A. keiskei is ‘Sinsuncho’ meaning the herb of eternal youth [1]. It is drunk as a tea and cooked as a vegetable. It is consumed as medicinal herb with tonic, mild cathartic, diuretic, and galactagogue effects [2]
Dulbecco’s modified Eagle medium (DMEM), penicillin, and streptomycin were purchased from Gibco (Invitrogen, Carlsbad, CA, USA)

Summary

Introduction

Angelica keiskei (Umbelliferae) is a perennial leafy herb, mainly distributed in Asian countries, including Korea and Japan. The herb is named as ‘Myeong-il yeob’ in Korean and ‘Ashitaba’ in Japanese, both literally meaning tomorrow’s leaves Another prevalent name in Korean for A. keiskei is ‘Sinsuncho’ meaning the herb of eternal youth [1]. In daily life, it is drunk as a tea and cooked as a vegetable. Preceding phytochemical investigations on A. keiskei revealed the presence of abundant prenylated chalcones in its leaves, stems, and roots [3] These chalcones are proposed as effective agents for diverse health-beneficial properties such as anti-tumor [4], anti-inflammatory [5], anti-bacterial [6], anti-diabetic [7], anti-melanogenic [8], and anti-obesity [9] effects.

Objectives

Methods

Conclusion