Icacinlactone H and Icacintrichantholide from the Tuber of Icacina trichantha

Abstract

The 17-norpimarane diterpene is a small group of natural products. A new member, icacinlactone H (1), and a new rearranged 17-norpimarane with an unprecedented carbon skeleton, icacintrichantholide (2), were isolated from Icacina trichantha. Their structures including the absolute configuration were elucidated by spectroscopic analysis, single-crystal X-ray diffraction, and electronic circular dichroism analysis. A plausible biogenetic pathway for 1 and 2 is proposed. Both 1 and 2 showed no significant activity against herpes simplex viruses HSV-1 and HSV-2 as well as the Epstein-Barr virus at 50 μM.

(9βH)-Pimaranes and Derivatives from the Tuber of Icacina trichantha

“…3–5, 7–9 Those diterpenoids bearing 9 β -H are generally more active. 3, 4 Based on the fact that 9-H (if any) of all Icacina diterpenoids is β -oriented, these compounds are proposed to be biosynthesized through a (9 β H)-pimarane pathway rather than a pimarane pathway, 5 as shown in Scheme 1.…”

“…1, 2 Our previous studies showed this plant is rich in (9 β H)-pimarane, 17- nor -(9 β H)-pimarane, and 17- nor -pimarane diterpenoids. 3–5 Furthermore, a rearranged 17- nor -pimarane poessessing an unprecedented carbon skeleton, icacintrichantholide, was identified. 5 Several of these compounds were cytotoxic against MDA-MB-435 (human melanoma cancer), MDA-MB-231 (human breast cancer), and OVCAR3 (human ovarian cancer) cell lines.…”

“…3–5 Furthermore, a rearranged 17- nor -pimarane poessessing an unprecedented carbon skeleton, icacintrichantholide, was identified. 5 Several of these compounds were cytotoxic against MDA-MB-435 (human melanoma cancer), MDA-MB-231 (human breast cancer), and OVCAR3 (human ovarian cancer) cell lines. 3, 4 During the course of continuing search for new chemical ingredients from I. trichantha , two 17- nor -pimaranes, two (9 β H)-pimaranes, and a 17- nor -(9 β H)-pimarane were obtained.…”

Di-nor- and 17-nor-pimaranes from Icacina trichantha

“…11 This is the first report of the isolation of a 16,17-di nor -pimarane ( 1 ) and a 17,19-di nor -pimarane ( 2 ) from Icacina plants. Theoretically, compound 1 could have been derived from the loss of either C15/C-16 or C16/C-17.…”

Natural Products Research in China From 2015 to 2016

“…Hyperattenin A ( 612 ) was characterized as a bicycle bicyclo[3.3.1]nonane derivative containing a rare hemiacetal functionality (Li et al, 2015a ). A new rearranged 17-norpimarane, icacintrichantholide 613 , was isolated from Icacina trichantha (Zhao et al, 2015a ). Three dimeric cadinane sesquiterpenoids, involucratustones A–C, were produced by the rhizomes of Stahlianthus involucratus .…”