M. Angeles Castro

Acetylated lignans from Juniperus sabina

Abstract Two new natural products, the acetates of epipodophyllotoxin and epipicropodophyllotoxin, were isolated from the lignan fraction of a n -hexane extract of the leaves of Juniperus sabina , along with deoxypodophyllotoxin, deoxipicropodophyllotoxin, (−)-deoxypodorhizon, β-peltatin A methyl ether and picropodophyllotoxin.

Cytotoxic cyclolignans related to podophyllotoxin

The cyclolignan family of natural products includes compounds with important antineoplastic and antiviral properties such as podophyllotoxin and two of their semisynthetic derivatives, etoposide and teniposide. The latter are included in a wide variety of cancer chemotherapy protocols. Due to these biological activities, cyclolignans have been the objective of numerous studies focused to prepare better and safer anticancer drugs. Several cyclolignans related to podophyllotoxin have been prepared and evaluated for their cytotoxic activities on four neoplastic cell lines (P-388, A-549, HT-29 and MEL-28); some of them have antiviral and immunosuppressive activities.

Synthesis and evaluation of pyrazolignans. A new class of cytotoxic agents.

A series of fused pyrazole derivatives of cyclolignans have been prepared through simple chemical routes and evaluated for their cytotoxic activities in culture cells of P-388 murine leukemia, A-549 lung carcinoma and HT-29 colon carcinoma. Despite the lack of the lactone moiety in their structures, they show IC50 values at microM levels.

Further antineoplastic terpenylquinones and terpenylhydroquinones.

Influences of the quinone/hydroquinone fragment and other structural features are considered in relation with the antineoplastic activity and selectivity of terpenylquinones/hydroquinones. Several compounds have shown IC50 values under the microM level.

Two diterpenoids from leaves of Juniperus sabina

Abstract Two new diterpenoids, 19-acetoxy-labd- 13( E )-en-8,15-diol and 4- epi -palustric acid 9α, 13α-endoperoxide, as well as some other known sesquiterpenoids and diterpenoids have been isolated from the n -hexane extract of J. sabina .

Synthesis and Cytotoxic Evaluation of 6-(3-Pyrazolylpropyl) Derivatives of 1,4-Naphthohydroquinone-1,4-diacetate

Several new 6‐(3‐pyrazolylpropyl) derivatives of 1,4‐naphthohydroquinone‐1,4‐diacetate (NHQ‐DA) have been prepared by chemical modifications of the Diels–Alder adduct of α‐myrcene and 1,4‐benzoquinone. All these new compounds and precursors have been evaluated in vitro for their cytotoxicity against cultured human cancer cells of MB‐231 breast‐adeno carcinoma, A‐549 lung carcinoma, and HT‐29 colon carcinoma. GI50 values ranged in and below the micromolar concentration level.

Synthesis, characterisation, and antineoplastic cytotoxicity of hybrid naphthohydroquinone–nucleic base mimic derivatives

From a partially degraded Diels–Alder adduct of α-myrcene and 1,4-benzoquinone, several model compounds belonging to a new series of 1,4-naphthohydroquinone derivatives have been prepared. Phenyl, pyridyl, imidazolyl and some nucleic base mimic heterocycles have been attached to the naphthohydroquinone system through linkers of different size and type, leading to potentially antineoplastic hybrid structures. The new compounds have been evaluated in vitro for their cytotoxicity against cultured human cancer cells of A-549 lung carcinoma, HT-29 colon adenocarcinoma and MDA-MB-231 breast carcinoma. GI50 values ranged in the μM level.

Cytotoxic‐Antineoplastic Derivatives of Prenyl‐1,2‐naphthohydroquinone

Several new prenyl‐1,2‐naphthohydroquinone derivatives have been prepared by chemical modifications of Diels–Alder products which were obtained from cycloaddition of α‐myrcene to 1,2‐benzoquinone and then evaluated in vitro for their cytotoxic activity against A‐549 lung carcinoma, HT‐29 colon carcinoma, and MB‐231 breast adeno‐carcinoma culture cells. Most of them exhibited GI50 values in the μM‐concentration level.

13C NMR DATA FOR 7- AND/OR 9-AZA-SUBSTITUTED NAPHTHALENECYCLOLIGNANS

13C NMR assignments are provided for 45 7‐ and/or 9‐aza‐substituted naphthalenecyclolignans.