State of knowledge: Histolocalisation in phytochemical study of medicinal plants.

BACKGROUND AND AIM: The renewed interest in medicinal plants has led us to examine more closely the usefulness of metabolite histolocalisation in screening work before any in-depth phytochemical studies. Indeed, this method is a histochemical technique allowing characterizing plant tissues constituents; and in particular metabolites of therapeutic interest, without destroying or altering as much as possible the studied plant material. This work aims at allowing us carring out a wide screening to highlight bioactive metabolites in plants studied from our rich university heritage collection. MATERIAL AND METHODS: The histochemical characterisation used in our work is a chemical, morphological and topographical (localisation) technique that uses precipitation reactions using dyes, among others. To do this we made thin cross-sections using razor blades on fresh plant material. The sections were then coloured using conventional chemical stains and observations were made using a MOTIC BA210 microscope equipped with a MOTICAM camera. RESULTS AND CONCLUSION: In view of obtained results, this technique, therefore, proves to be a useful screening and analysis method when applied in phytochemical studies on plants such as Datura stramonium, Peperomia obtusifolia, Cecropia obtusa, Orthosiphon aristatus and Vitex agnus castus. The obtained results confirm presence of sought metabolites, and allow their precise histological localisation. This will make extraction process more profiTable, simpler or even more ecological by avoiding waste.

Velamo do campo: its volatile constituents, secretory elements, and biological activity.

The volatile components from Croton campestris root bark were localized by an anatomical study and analyzed by gas chromatography-mass spectrometry for the first time. The roots of this plant showed secretory cells. These volatile constituents, isolated from the dichloromethane extract by hydrodistillation, were analyzed by gas chromatography-mass spectrometry. We found 69 components. They were characterized, and the major constituents of crude oil root barks were spathulenol (23.3%) and borneol (18.7%). Growth inhibitory activity of the active compounds in solution was evaluated by measuring minimal inhibitory concentrations using a broth micromethod. The minimal inhibitory concentration of root bark volatile constituents was 1.56 µg/mL for Staphylococcus aureus, 3.125 µg/mL for Candida albicans, and 6.25 µg/mL for Aspergillusniger.

Oregano: chemical analysis and evaluation of its antimalarial, antioxidant, and cytotoxic activities.

GC-FID and GC-MS analysis of essential oil from oregano leaves (Origanum compactum) resulted in the identification of 46 compounds, representing more than 98% of the total composition. Carvacrol was the predominant compound (36.46%), followed by thymol (29.74%) and p-cymene (24.31%). Serial extractions with petroleum ether, ethyl acetate, ethanol, and water were performed on aerials parts of Origanum compactum. In these extracts, different chemical families were characterized: polyphenols (gallic acid equivalent 21.2 to 858.3 g/kg), tannins (catechin equivalent 12.4 to 510.3 g/kg), anthocyanins (cyanidin equivalent 0.38 to 5.63 mg/kg), and flavonoids (quercetin equivalent 14.5 to 54.7 g/kg). The samples (essential oil and extracts) were subjected to a screening for antioxidant (DPPH and ABTS assays) and antimalarial activities and against human breast cancer cells. The essential oil showed a higher antioxidant activity with an IC50=2±0.1 mg/L. Among the extracts, the aqueous extract had the highest antioxidant activity with an IC50=4.8±0.2 mg/L (DPPH assay). Concerning antimalarial activity, Origanum compactum essential oil and ethyl acetate extract showed the best results with an IC50 of 34 and 33 mg/mL, respectively. In addition, ethyl acetate extract (30 mg/L) and ethanol extract (56 mg/L) showed activity against human breast cancer cells (MCF7). The oregano essential oil was considered to be nontoxic.

Chemical study, antimalarial and antioxidant activities, and cytotoxicity to human breast cancer cells (MCF7) of Argania spinosa.

INTRODUCTION: In our work, we evaluate the potential antioxidant, antimalarial activity and also activity against human breast cancer cells (MCF7) of Argan fruit extracts using in vitro models to validate the traditional use of this plant. Its chemical composition was also studied to begin the understanding of its activities, waiting to find the structure-activity relationship. RESULTS: Polyphenols (89.4-218.5 eqGallic acid (mg/g dry)), tannins (39.3-214.0 eqCatechin (mg/g dry)), flavonoids (3.4-11.1 eqQuercetin (mg/g dry)) and anthocyanins (0.74-10.92 eqCyanindin (mug/g dry)) were quantified. A good (ethyl acetate and decoction) and moderate (petroleum ether) antioxidant activity were obtained for DPPH (IC(50) 32.3-600.8 microg/ml) and ABTS (IC(50) 11.9-988.8 microg/ml) assays. In addition, we found a good antimalarial activity (IC(50) 35 to >100 microg/ml) and human breast cancer cells activity (IC(50) 42 to >100 microg/ml). CONCLUSIONS: The ethyl acetate extract and the decoction show interesting antimalarial and antioxidant activities. The results indicate a good correlations between anthocyanins quantitiy and the potential antioxidant (R(2)=0.9867) and also to antimalarial activity (R(2)=0.8175).