Monoterpenes have been identified as responsible of important therapeutic effects of plant-extracts. In this work, we try to compare the cytotoxic effect of six monoterpenes (carvacrol, thymol, carveol, carvone, eugenol and isopulegol) as well as their molecular mechanisms. The in vitro antitumor activity of the tested products, evaluated against five tumor cell lines, show that the carvacrol is the most cytotoxic monoterpene. The investigation of an eventual synergistic effect of the six natural monoterpenes with two anticancer drugs revealed that there is a significant synergy between them (p<5%). On the other hand, the effect of the tested products on cell cycle progression was examined by flow cytometry after DNA staining in order to investigate the molecular mechanism of their cytotoxic activity. The results revealed that carvacrol and carveol stopped the cell cycle progression in S phase; however, thymol and isopulegol stopped it in G0/G1 phase. Regarding carvone and eugenol, no effect on cell cycle was observed.

This investigation aimed to evaluate the in vitro and in vivo antitumor potential of a Moroccan propolis extracts. For in vitro assays, three mammalian tumor cell lines were used: BSR (hamster renal adenocarcinoma), Hep-2 (human laryngeal carcinoma) and P815 (murin mastocytoma). The propolis ethanolic extract as well as the ethyl acetate extract, exert an in vitro cytotoxic activity in dose-dependent manner. The IC50 values were ranging from 15 µg/mL to 38 µg/mL. This activity depends not only on the extract's chemical composition (analysed by HPLC/ESI-MS), but also on the target tumor cells. Interestingly, the cytotoxic effect of these extracts on the normal human peripheral blood mononuclear cells (PBMC) was weak when compared to that induced on tumor cells. On the other hand, oral route treatment of P815 tumor-bearing mice (DBA2/P815) with propolis ethanolic extract (5 mg per mouse every fourth day, five times for group A, and 2.5 mg per mouse every fourth day, five times for group B) significantly reduced the tumor volume (1.2 cm³ for group A and 2.7 cm³ for group B at the 22nd day after tumor graft). These effects are statistically significant as compared to those obtained with the control untreated mice (tumor volume 3.5 cm³ at day 22).

Artemisia herba-alba Asso., Asteraceae, is widely used in Morrocan folk medicine for the treatment of different health disorders. However, no scientific or medical studies were carried out to assess the cytotoxicity of A. herba-alba essential oil against cancer cell lines. In this study, eighteen volatile compounds were identified by GC-MS analysis of the essential oil obtained from the plant's aerial parts. The main volatile constituent in A. herba-alba was found to be a monoterpene, Verbenol, contributing to about 22% of the total volatile components. The essential oil showed significant antiproliferative activity against the acute lymphoblastic leukaemia (CEM) cell line, with 3 µg/mL as IC50 value. The anticancer bioactivity of Moroccan A. herba-alba essential oil is described here for the first time.

Muitas espécies de Tomilho têm sido amplamente utilizadas na medicina popular morroquina como agentes antiinflamatório, antioxidante e antinociceptivo. Este estudo foi realizado para analisar a composição química e a atividade antitumoral in vitro dos óleos essenciais e de vários extratos de espécies de tomilho coletadas em diferentes regiões do Marrocos. O óleo essencial, obtido através de hidrodestilação, e os vários extratos, obtidos por extração em aparelho de Soxhlet, utilizando solventes de diferentes polaridades, foram analisados através de cromatografia gasosa acoplada à espectrometria de massas (CG/EM). Tanto os componentes majoritários quanto os minoritário foram analisados. De um modo geral, os constituintes principais da composição química das populações de tomilho morroquinas foram carvacrol, timol, borneol e p-cimeno. A quantidade desses componentes pode ser de 85%, 42%, 59%, e 23%, respectivamente. Em adição, os óleos essenciais bem como dois produtos puros (carvacrol e timol) foram testados quanto à sua atividade antitumoral contra mastocitoma da linhagem P815. Enquanto todos esses produtos mostraram efeito citotóxico dependente da dose, o carvacrol foi o mais citotóxico quando comparado aos outros. Interessantemente, quando estes produtos foram testados contra células mononucleares sangüíneas periféricas humanas normais, mostraram efeito proliferativo em vez de citotóxico.

Many species of Thyme have been widely used in Moroccan folk medicine as anti-inflammatory, antioxidant and antinociceptive agents. This study was designed to examine the chemical composition and the in vitro antitumor activity of the essential oils and various extracts of thyme species collected in different regions of Morocco. The essential oil, obtained by hydrodistillation, and the various extracts, obtained by Soxhlet extraction, using solvents of varying polarity, were analysed by gas chromatography coupled to mass spectrometry (GC-MS). Both major and trace components were analysed. Overall, the major constituents in the chemical composition of Moroccan thyme populations were carvacrol, thymol, borneol and p-cymene. The rate of these components can hit respectively to 85%, 42%, 59%, and 23%. Furthermore, the essential oils as well as two pure products (carvacrol and thymol) were tested for their antitumoral activity against P815 mastocytoma cell line. While all these products showed a dose dependent cytotoxic effect, the carvacrol was the most cytotoxic one compared to the others. Interestingly, when these products were tested against the normal human peripheral blood mononuclear cells, they show a proliferative effect instead of a cytotoxic one.