Astin A

Antitumor astins originate from the fungal endophyte Cyanodermella asteris living within the medicinal plant Aster tataricus.[Pubmed:31811021]

Proc Natl Acad Sci U S A. 2019 Dec 6. pii: 1910527116.

Medicinal plants are a prolific source of natural products with remarkable chemical and biological properties, many of which have considerable remedial benefits. Numerous medicinal plants are suffering from wildcrafting, and thus biotechnological production processes of their natural products are urgently needed. The plant Aster tataricus is widely used in traditional Chinese medicine and contains unique active ingredients named astins. These are macrocyclic peptides showing promising antitumor activities and usually containing the highly unusual moiety 3,4-dichloroproline. The biosynthetic origins of astins are unknown despite being studied for decades. Here we show that astins are produced by the recently discovered fungal endophyte Cyanodermella asteris We were able to produce astins in reasonable and reproducible amounts using axenic cultures of the endophyte. We identified the biosynthetic gene cluster responsible for astin biosynthesis in the genome of C. asteris and propose a production pathway that is based on a nonribosomal peptide synthetase. Striking differences in the production profiles of endophyte and host plant imply a symbiotic cross-species biosynthesis pathway for astin C derivatives, in which plant enzymes or plant signals are required to trigger the synthesis of plant-exclusive variants such as Astin A. Our findings lay the foundation for the sustainable biotechnological production of astins independent from aster plants.

Simultaneous separation and determination of phenolic acids, pentapeptides, and triterpenoid saponins in the root of Aster tataricus by high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry.[Pubmed:25491750]

J Sep Sci. 2015 Feb;38(4):571-5.

We established a qualitative method to analyze the main chemical compositions of the root of Aster tataricus. Most of the peaks were separated on a C(18) column packed with 5.0 mum particles, and 28 compounds were identified, including 11 chlorogenic acids, ten astins/asterinins, and seven astersaponins, four of which were reported for the first time from A. tataricus. Furthermore, we developed a reliable method for the simultaneous quantification of 3-caffeoylquinic acid, 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, Astin A, astin B, astin C, astersaponin A, and astersaponin C, and the qualified separations were achieved only on a C18 column packed with 2.7 mum particles. The method was used to measure the concentrations of eight components in samples from two major producing areas in China, and the average contents in samples from Bozhou (Anhui) were higher than those in samples from Anguo (Hebei).