Microwave-assisted extraction (MAE) or simply microwave extraction is a relatively new extraction technique that combines microwave and traditional solvent extraction. Application of microwaves for heating the solvents and plant tissues in extraction process, which increases the kinetic of extraction, is called microwave-assisted extraction. MAE has a number of advantages, e.g., shorter extraction time, less solvent, higher extraction rate and lower cost, over traditional method of extraction of compounds from various matrices, especially natural products. The use of MAE in natural products extraction started in the late 1980s, and through the technological developments, it has now become one of the popular and cost-effective extraction methods available today, and several advanced MAE instrumentations and methodologies have become available, e.g., pressurized microwave-assisted extraction (PMAE) and solvent-free microwave-assisted extraction (SFMAE). This chapter provides an overview of the MAE and presents a number of specific protocols for natural products extraction.

Background and the purpose of the studyThe objectives of the present study were phytochemical screening and study of the effects of ethanolic extract of aerial parts of Ocimum basilicum (basil) on cardiac functions and histopathological changes in isoproterenol-induced myocardial infarction (MI).MethodsThe leaves of the plant were extracted with ethanol by maceration and subjected to colorimetry to determine flavonoids and phenolic compounds. High-performance TLC analysis and subsequent CAMAG's TLC scanning were performed to quantify rosmarinic acid content. Wistar rats were assigned to 6 groups of normal control, sham, isoproterenol, and treatment with 10, 20, and 40 mg/kg of the extract two times per day concurrent with MI induction. A subcutaneous injection of isoproterenol (100 mg/kg/day) for 2 consecutive days was used to induce MI.ResultsPhytochemical screening indicated the presence of phenolic compounds (5.36%) and flavonoids (1.86%). Rosmarinic acid was the principal phenolic compound with a 15.74% existence. The ST-segment elevation induced by isoproterenol was significantly suppressed by all doses of the extract. A severe myocardial necrosis and fibrosis with a sharp reduction in left ventricular contractility and a marked increase in left ventricular end-diastolic pressure were seen in the isoproterenol group, all of which were significantly improved by the extract treatment. In addition to in-vitro antioxidant activity, the extract significantly suppressed the elevation of malondialdehyde levels both in the serum and the myocardium.ConclusionThe results of the study demonstrate that Ocimum basilicum strongly protected the myocardium against isoproterenol-induced infarction and suggest that the cardioprotective effects could be related to antioxidative activities.

BackgroundCynodon dactylon, a valuable medicinal plant, is widely used in Iranian folk medicine for the treatment of various cardiovascular diseases such as heart failure and atherosclerosis. Moreover, its anti-diabetic, anti-cancer and anti-microbial properties have been also reported. Concerning the critical role of angiogenesis in the incidence and progression of tumors and also its protective role in cardiovascular diseases, we investigated the effects of the aqueous extract prepared from the rhizomes of C. dactylon on vascular endothelial growth factor (VEGF) expressions in Human Umbilical Vein Endothelial Cells (HUVECs) and also on angiogenesis in carrageenan induced air-pouch model in rats.MethodsIn the air-pouch model, carrageenan was injected into an air-pouch on the back of the rats and following an IV injection of carmine red dye on day 6, granulation tissue was processed for the assessment of the dye content. Furthermore, in an in vitro study, angiogenic property of the extract was assessed through its effect on VEGF expression in HUVECs.ResultsOral administration of 400 mg/kg/day of the extract significantly increased angiogenesis (p < 0.05) and markedly decreased neutrophil (p < 0.05) and total leukocyte infiltration (p < 0.001) into the granulation tissues. Moreover, the extract increased the expression of total VEGF in HUVECs at a concentration of (100 μl/ml).ConclusionThe present study showed that the aqueous extract of C. dactylon promotes angiogenesis probably through stimulating VEGF expression.

Obesity is a major health problem world-wide. Medical intervention is often needed to tackle this problem, and accordingly the need for developing more effective, safer and cheaper weight reducing drugs has become paramount in recent years. In the present study, the effects of lime (Citrus aurantifolia) essential oils in reducing body weight, individually and in co-administration with ketotifen, an antihistaminic drug that causes weight gain, has been investigated using a mouse model. During the 45 days experimental period, the mice that received ketotifen demonstrated an enhancement both in the amount of food intake and body weight compared with the control group. Groups treated with lime essential oil displayed a reduction in body weight and food consumption in mice, possibly through promoting anorexia which might have played a role in weight loss. Interestingly, co-administration of the lime essential oil and ketotifen caused significant suppression in gaining weight, as well as decreased body weights of mice. The data obtained in this study suggested that lime essential oil plays an important role in weight loss and could be useful in the treatment of drug-induced obesity and related diseases. The GC-MS analysis of the essential oils of C. aurantifolia was also performed and approximately 22 main components, with limonene (28.27%) being the principal one, were identified and quantified.

This study evaluated the effects of a hydro-alcoholic extract of Melissa officinalis (HAEMO) on anxiety-and depressive-like behaviours, oxidative stress and apoptosis markers in restraint stress-exposed mice. In order to induce a depression-like model, mice were subjected to restraint stress (3 h day −1 for 14 days) and received normal saline or HAEMO (50, 75 and 150 mg kg −1 day −1 ) for 14 days. The administered doses of HAEMO were designated based on the concentration of one of the main phenolic compounds present in the extract, rosmarinic acid (2.55 mg kg −1 at lowest dose); other phytochemical analyses including assays for antioxidant activity, total phenols and flavonoids were also carried out. The behavioural changes in an open field task, elevated plus maze, tail suspension and forced swimming tests were evaluated. Also, malondialdehyde (MDA) levels and enzyme activities of superoxide dismutase and glutathione peroxidase, and total antioxidant capacity were assessed in the prefrontal cortex and hippocampus. Moreover, levels of Bcl-2, Bax and caspase 3 in the brain as well as serum concentration of corticosterone were evaluated. HAEMO (75 and 150 mg kg −1 ) significantly reversed anxiety-and depressive-like behaviours. Also, HAEMO reduced MDA levels, enhanced enzymatic antioxidant activities and restored serum levels of corticosterone. An immunoblotting analysis also demonstrated that HAEMO decreased levels of pro-apoptotic markers and increased anti-apoptotic protein levels in the prefrontal cortex and hippocampus of restraint stress-exposed mice. Our findings suggested that HAEMO reduced inflammation and had anxiolytic and antidepressant effects in mice.

Aim: Developing antitumor drugs from natural products is receiving increasing interest worldwide due to limitations and side effects of therapy strategies for the second leading cause of disease related mortality, cancer. Methods: The antiproliferative activity of a methanolic extract from the aerial parts of Marrubium persicum extract was assessed with the MCF-7 breast cancer cell line using the MTT test for cell viability and cytotoxicity indices. In addition, antioxidant properties of the extract were evaluated by measuring its ability to scavenge free DPPH radicals. Moreover, the total phenolic and flavonoid content of the extract was determined based on Folin-Ciocalteu and colorimetric aluminum chloride methods. Results: The findings of the study for the antiproliferative activity of the methanolic extract of M. persicum showed that growth of MCF-7 cells was inhibited by the extract in a dose and time dependent manner, where a gradual increase of cytotoxicity effect has been achieved setting out on 200 µg/mL concentration of the plant extract. The antioxidant assay revealed that the extract was a strong scavenger of DPPH radicals with an RC 50 value of 52 µg/mL. The total phenolic and flavonoids content of the plant extract was 409.3 mg gallic acid equivalent and 168.9 mg quercetin equivalent per 100g of dry plant material. Conclusion: Overall, M. persicum possesses potential antiproliferative and antioxidant activities on the malignant MCF-7 cell line that could be attributed to the high content of phenolics and flavonoids, and therefore warrants further exploration.

In the present investigation metronidazole-loaded alginate beads consisting of calcium silicate as a porous carrier or NaHCO(3) as a gas-forming agent were prepared for local eradication of Helicobacter Pylori. Gelation method was used for preparation of conventional sodium alginate beads. Drug entrapment efficiency, drug loading, floating properties, drug release, crystallinity and release kinetic as well as morphology of the prepared beads were assessed. The silicate based beads showed slower release pattern, compared to the gas-forming beads due to network structure strengthening effect of the calcium silicate. Furthermore, the gas-forming-based beads had shorter initial buoyancy lag time, owing to the fact that the NaHCO(3) produced larger pores than those of silicate treated ones. Drug entrapment efficiency ranged between 61.7 and 93.1% for the prepared formulations. The maximum value of drug loading for gas-forming and silicate-based beads were 66.64% and 34.97%, respectively. Kinetically, release pattern of metronidazole in simulated gastric fluid from the beads fitted best to Reciprocal powered time, Weibull and log-probability models with the respect overall mean percentage error values of 4.50, 5.30 and 7.76. By and large, these systems can float in the gastric condition and control the drug release from the beads.

Developing an efficient floating dosage form is reliant on a better understanding of the relation between formulation variables and performance of the floating systems. Generally, the combination of two buoyancy mechanisms and gas-generating systems with swellable polymers would be beneficial for obtaining an appropriate floating lag time and duration of buoyancy, which in turn guarantees optimum efficiency of the pharmaceutical dosage form.