Cycloartane- and Lanostane-Type Triterpenoids from the Resin of Parthenium argentatum AZ-2, a Byproduct of Guayule Rubber Production

Ya-Ming Xu; Chandrashekhar Madasu; Manping X Liu; E M Kithsiri Wijeratne; David Dierig; Bob White; István Molnár; A A Leslie Gunatilaka

doi:10.1021/acsomega.1c01714

Cycloartane- and Lanostane-Type Triterpenoids from the Resin of Parthenium argentatum AZ-2, a Byproduct of Guayule Rubber Production

ACS Omega. 2021 Jun 4;6(23):15486-15498. doi: 10.1021/acsomega.1c01714. eCollection 2021 Jun 15.

Authors

Ya-Ming Xu¹, Chandrashekhar Madasu¹, Manping X Liu¹, E M Kithsiri Wijeratne¹, David Dierig², Bob White², István Molnár¹, A A Leslie Gunatilaka¹

Affiliations

¹ Southwest Center for Natural Products Research, School of Natural Resources and the Environment, College of Agriculture and Life Sciences, University of Arizona, 250 E. Valencia Road, Tucson, Arizona 85706, United States.
² Guayule Research, Bridgestone Americas, Inc., 4140 West Harmon Road, Eloy, Arizona 85131, United States.

Abstract

A total of 12 new cycloartane- and lanostane-type triterpenoids including 16-deoxyargentatin A (1), 16-deoxyisoargentatin A (2), 7-oxoisoargentatin A (3), 24-epi-argentatin H (4), 24-O-p-anisoylargentatin C (5), 24-O-trans-cinnamoylargentatin C (6), 16-dehydroargentatin C (7), 16,17(20)-didehydroargentatin C (8), isoargentatin C (9), isoargentatin H (10), 3-epi-quisquagenin (11), and isoquisquagenin (12) together with 10 known triterpenoids (13-22) were isolated from the resin of Parthenium argentatum AZ-2 obtained as a byproduct of Bridgestone guayule rubber production. The structures of new triterpenoids 1-12 and argentatin H (13), which has previously been characterized as its diacetate (23), were elucidated by extensive analysis of their spectroscopic data and chemical conversions, and the known compounds 14-22 were identified by comparison of their spectroscopic data with those reported. Of these, 13, 14, and 18 exhibited weak cytotoxic activity for several cancer cell lines.