Laura Faiella

Diterpenes and phenolic compounds from Sideritis pullulans

Phytochemical investigation of Sideritis pullulans aerial part and root extracts allowed to isolate six ent-kaurane diterpenes, two phenylpropanoids, and one coumarin, identified as 1α,3α,7β,18-tetrahydroxy-ent-kaur-16-ene (sideripullol A) (1), 3α,11α,18-trihydroxy-ent-kaur-16-ene (sideripullol B) (2), 3α,7β,18-trihydroxy-17-nor-ent-kauran-16-one (sideritone A) (3), 3α,7β-dihydroxy-18-acetyloxy-17-nor-ent-kauran-16-one (sideritone B) (4), 3α,7β,16α,17-tetrahydroxy-18-acetyloxy-ent-kaurane (sideripullol C) (5), 7β,16α,17,18-tetrahydroxy-ent-kaurane (sideripullol D) (6), β-(3-methoxy-4-hydroxyphenyl)-ethyl-O-α-l-arabinopiranosyl-(1→2)-α-l-rhamnopyranosyl-(1→3)-6-O-t-feruloyl-β-d-glucopyranoside (sideritiside A) (7), β-(3,4-dihydroxyphenyl)-ethyl-O-α-l-arabinopiranosyl-(1→2)-α-l-rhamnopyranosyl-(1→3)-6-O-t-feruloyl-β-d-glucopyranoside (sideritiside B) (8), and 7-demethyl-8-methoxycoumarsabin (9), respectively. Twenty known compounds, including phenolics, flavonol glycosides, iridoids, diterpenes, sesquiterpenes, lignans, coumarins, and phenylpropanoids were also isolated and characterized. All diterpenes were evaluated for their cytotoxic activity.

Diterpenes and Phenylpropanoids from Clerodendrum splendens

Four new clerodane diterpenes (1-4) and one new phenylpropanoid (5) have been isolated from Clerodendrum splendens aerial parts, together with nine known compounds. Their structures were determined by spectroscopic and spectrometric analysis and chemical methods. The absolute configuration of the 15,16-diol moiety in 4 was determined by Snatzkes method. Antiproliferative activity of diterpenes in HeLa cells was also evaluated. The IC50 values were 98 ± 11 µM for 3 and 101 ± 8 µM for 1, respectively.