The medicinal benefits of Plantago major have been acknowledged around the world for hundreds of years. This plant contains a number of effective chemical constituents including flavonoids, alkaloids, terpenoids, phenolic acid derivatives, iridoid glycosides, fatty acids, polysaccharides and vitamins which contribute to its exerting specific therapeutic effects. Correspondingly, studies have found that Plantago major is effective as a wound healer, as well as an antiulcerative, antidiabetic, antidiarrhoeal, anti-inflammatory, antinociceptive, antibacterial, and antiviral agent. It also combats fatigue and cancer, is an antioxidant and a free radical scavenger. This paper provides a review of the medicinal benefits and chemical constituents of Plantago major published in journals from year 1937 to 2015 which are available from PubMed, ScienceDirect and Google Scholar.

Thymus vulgaris L. (Lamiaceae) is a well-known medicinal plant that contains important compounds such as thymol and carvacrol and it has been used in many pharmaceutical dosage forms. Thymol and carvacrol in essential oils are often quantified by gas chromatography (GC) technique but in this work, a validated and reliable high performance liquid chromatography (HPLC) method has been developed for the analysis of these two components in T. vulgaris essential oil. The essential oil of the plant was analyzed by HPLC and GC techniques. The HPLC system consisted of ACE C18 column and an isocratic acetonitrile:water (50:50) as the mobile phase which was kept at a flow rate of 1 ml/min. The method was validated for selectivity, linearity (r2 > 0.997 for both thymol and carvacrol), precision (intra-day 0.8-1.9, 1.7-2.6; and inter-day 3.5-4.5, 3.6-4.7) and recovery (97.7%, 97.6%) for thymol and carvacrol, respectively. The limits of detection (LODs) and limits of quantization (LOQs) were calculated to be 2.8, 0.6 µg/ml and 8.6, 1.8 µg/ml for thymol and carvacrol, respectively. The GC system consisted of flame ionization detector (FID) and CP-SIL 8 column. The concentrations of thymol and carvacrol in essential oil obtained by HPLC (41.2%, 4.3%) and GC (40.7%, 4.2%) were compared by statistical methods and they showed good agreement.

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Purpose Various studies suggest that some of natural agents create a specific action of hypocholesterolemic effect. Considering this fact, the aim of this paper is to work on describing selected natural agents that may reduce cholesterol concentrations by different mechanism of actions. Design/methodology/approach The advantages, phytochemical components and the mechanisms of the agents were reviewed and supported from the findings of the in vitro, double-blind and clinical studies from published journals, books and articles. The journals used in this review were published between 1987 and 2016, and are available from PubMed, ScienceDirect and Google Scholar. Findings Plant stanols and sterols, turmeric, fenugreek, avocado, tomato, artichoke, red yeast rice and garlic showed a positive effect in maintaining cholesterol levels by specific mechanisms or actions. These agents each had a specific action in creating a hypocholesterolemic effect either by inhibition of the enzyme significant to the synthesis process, disturbing the absorption of cholesterol, conversion of cholesterol to other related forms and through the reduction of the oxidative stress. Research limitations/implications However, this field still needs more studies as, currently, there is not any detailed information regarding the main active ingredients responsible for the mechanism to reduce cholesterol levels in humans. Originality/value This paper enlightens the authors’ understanding of some natural agents that have the potential to be used in controlling cholesterol.