Antimicrobial and Antiparasitic Abietane Diterpenoids from the Roots of Clerodendrum eriophyllum

Abstract

Chromatographic separation of the roots of a Kenyan medicinal plant, Clerodendrum eriophyllum, led to the isolation of ten abietane diterpenoids (1-10), one of which (1) was isolated for the first time from a natural source. Using spectroscopic data, the structure of 1 was determined to be 12-hydroxy-8,12-abietadiene-3,11,14-trione. Circular dichroism (CD) spectra showed that the stereochemistry of compounds 1, 3, and 6-8 belongs to the normal series of abietane diterpenes, which confirmed the absolute stereochemistry of the isolated compounds. Compounds 2-10 were evaluated for their in vitro antiplasmodial, antileishmanial, antifungal and antibacterial activities. Compounds 3 and 7 exhibited potent antifungal activity (IC50/MIC 0.58/1.25 and 0.96/2.5 µg/mL, respectively) against C. neoformans, whereas 3, 6 and 7 showed strong antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus with IC50/MIC values between 1.33–1.75/2.5–5 and 0.96–1.56/2.5 µg/mL, respectively. In addition, compounds 3 and 9 exhibited potent antileishmanial activity (IC50 0.08 and 0.20 µg/mL, respectively) against L. donovani, while 3 and 7 displayed weak antimalarial activity against Plasmodium falciparum, but 9 was inactive.

In Vitro Antiprotozoal Activity of Abietane Diterpenoids Isolated from Plectranthus barbatus Andr.

“…These results are in agreement with literature data on diterpenoids isolated from other plant species [19–25]. Our result for taxodione ( 3 ) was consistent with that obtained by Machumi et al [19] who reported antileishmanial and antimalarial activities for taxodione isolated from the roots of Clerodendrum eriophyllum .…”

“…Our result for taxodione ( 3 ) was consistent with that obtained by Machumi et al [19] who reported antileishmanial and antimalarial activities for taxodione isolated from the roots of Clerodendrum eriophyllum . Van Zyl et al [20] reported on seven abietane diterpenes from the Plectranthus species P. hadiensis , P. lucidus , P. ecklonii , P. purpuratus subsp.…”

Antileishmanial and Cytotoxic Activity of Some Highly Oxidized Abietane Diterpenoids from the Bald Cypress, Taxodium distichum

“…18 Compound 10 has been described in the past as a potent antileishmanial agent against L. donovani promastigotes in vitro after it was isolated from other plant species, including Clerodendrum eriophyllum Gürke (Verbenaceae) and Cupressus sempervirens L. (Cupressaceae). 43,44 More recently, this compound has been reported to be an inhibitor of human and trypanosomal farnesyl diphosphate synthase (FPPS), 45 which could explain the biological activity observed both in this study and in others, but putatively for 2 as well based on their structural similarity. Many of the compounds isolated from the active fraction were tested but were inactive (IC 50 >10 μM) in the antileishmanial bioassays.…”

Identification of new p300 histone acetyltransferase inhibitors from natural products by a customized virtual screening method

“…Compound NP-15 (taxodione) is an abietane diterpenoid, which can be separated from the roots of a Kenyan medicinal plant, Clerodendrum eriophyllum. 16 NP-15 has a simple, different scaffold compared with NP-2, NP-3 and NP-9, and its p300 HAT inhibitory activity may be due to predicted hydrogen bonds with the three key residues observed in docking studies (Fig. 3D).…”