Diterpenes Isolated from Three Different Plectranthus Sensu Lato Species and Their Antiproliferative Activities against Gynecological and Glioblastoma Cancer Cells

TL;DR

This study isolated diterpenes from three Plectranthus species and found some to be highly effective at stopping the growth of gynecological and brain cancer cells.

Contribution

The discovery of three new diterpenes and their strong antiproliferative activity against glioblastoma and gynecological cancer cells.

Findings

Three new diterpenes were isolated from Coleus comosus.

Royleanone- and hydroquinone-type abietane diterpenes showed the strongest antiproliferative effects.

IC50 values for these diterpenes against glioblastoma cells ranged from 1.1 to 15.6 μM.

Abstract

Fourteen diterpenes were isolated from methanol extracts of the
aerial parts ofColeus comosus,Coleus forsteri “Marginatus”, and Plectranthus ciliatus. The compounds belong to the
abietane (1–4, 9–11, and 13), ent-clerodane (5–8), and ent-kaurane
(14, 15) classes. Three new compounds were
isolated from C. comosus, including 3-O-acetylornatin G (2), 3,12-di-O-acetylornatin
G (3), ornatin B methyl ester (5), and ornatin
F (4), for which we proposed a revised structure. The
structures of the compounds were determined by comprehensive spectroscopic
data analysis. The isolated diterpenes were examined in silico for
their physicochemical and early ADME properties. Their antiproliferative
effects were determined in vitro using human breast (MDA-MB-231 and
MCF-7), cervical (HeLa), and glioblastoma (U-87 MG) cancer cell lines.
The royleanone- and hydroquinone-type abietane diterpenes (9–13)exhibited the most potent antiproliferative
activity against all cancer cell lines tested, particularly against
glioblastoma cells, with IC50 values ranging from 1.1 to
15.6 μM.

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