摘要：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.
