Synthesis of silver nanoparticles: chemical, physical and biological methods

Silver nanoparticles (NPs) have been the subjects of researchers because of their unique properties (e.g., size and shape depending optical, antimicrobial, and electrical properties). A variety of preparation techniques have been reported for the synthesis of silver NPs; notable examples include, laser ablation, gamma irradiation, electron irradiation, chemical reduction, photochemical methods, microwave processing, and biological synthetic methods. This review presents an overview of silver nanoparticle preparation by physical, chemical, and biological synthesis. The aim of this review article is, therefore, to reflect on the current state and future prospects, especially the potentials and limitations of the above mentioned techniques for industries.

Phytochemical analysis of Pinus eldarica bark

Bark extract of Pinus pinaster contains numerous phenolic compounds such as catechins, taxifolin, and phenolic acids. These compounds have received considerable attentions because of their anti-inflammatory, antimutagenic, anticarcinogenic, antimetastatic and high antioxidant activities. Although P. pinaster bark has been intensely investigated in the past; there is comparably less information available in the literature in regard to P. eldarica bark. Therefore, the aim of this study was to determine the chemical composition of P. eldarica commonly found in Iran. A reversed-phase high pressure liquid chromatography (RP-HPLC) method for the determination of catechin, caffeic acid, ferulic acid, and taxifolin in P. pinaster and P. eldarica was developed. A mixture of 0.1% formic acid in deionized water and 0.1% formic acid in acetonitrile was used as the mobile phase, and chromatographic separation was achieved on a Nova pack C18 at 280 nm. The two studied Pinus species contained high amounts of polyphenolic compounds. Among four marker compounds, the main substances identified in P. pinaster and P. eldarica were taxifolin and catechin, respectively. Furthermore, the composition of the bark oil of P. eldarica obtained by hydrodistillation was analyzed by gas chromatography/mass spectroscopy (GC/MS). Thirty-three compounds accounting for 95.1 % of the oil were identified. The oils consisted mainly of mono- and sesquiterpenoid fractions, especially α-pinene (24.6%), caryophyllene oxide (14.0%), δ-3-carene (10.7%), (E)-β-caryophyllene (7.9%), and myrtenal (3.1%).

The effects of chloroform, ethyl acetate and methanolic extracts of Brassica rapa L. on cell-mediated immune response in mice

Turnips with a long history of usage, are helpful in preventing breast and prostate cancer, inflammation and body`s immune system dysfunction. In this study, we investigated the effects of chloroform, ethyl acetate and methanolic extracts of Brassica rapa L. on cell-mediated immune response in mice. Chloroform, ethyl acetate and methanolic extracts of B. rapa glands were prepared by maceration method. To study the effects of B. rapa on acquired immunity, groups of Balb/c mice (n=8) were used. Sheep red blood cell (SRBC) was injected (s.c., 1×10(8)cells/ml, 0.02 ml) and 5 days later, different extracts (10, 100 and 500 mg/kg), betamethasone (4 mg/kg) and Levamisol (4 mg/kg) as a positive control and normal saline as a negative control were given i.p. After 1 h SRBC was injected to footpad (s.c., 1×10(8)cells/ml, 0.02 ml) and footpad swelling was measured up to 72 h. To investigate the effects of B. rapa on innate immunity the same procedure was used, but animals only received one injection of SRBC 1 h after i.p. injection of test compounds. Our findings showed that SRBC induced an increase in paw swelling with maximum response at 6-8 and 2-4 h for innate and acquired immunity, respectively. Betamethasone inhibited and levamisol increased paw thickness in both models. In both innate and acquired immunity models, chloroform, ethyl acetate and methanolic extracts of B. rapa glands significantly and dose-dependently reduced paw thickness. Ethyl acetate extract showed better effect. As glucosinolates are better extracted by ethyl acetate, it may be concluded that they are contributed in the more pronounced effects of ethyl acetate extract.

Effects of methanolic and butanolic fractions of Allium elburzense Wendelbo bulbs on blood glucose level of normal and STZ-induced diabetic rats

Allium elburzense (A. elborzense, Alliaceae), a plant rich in saponins, is an edible vegetable in northern Iran with a folk background use as antidiabetic which has not yet been examined for this indication. To evaluate the antidiabetic potential of A. elburzense, its hydroalcoholic (HdAE) and butanolic extracts (BuE) were examined. The acute (1, 2, 3, 4, 8 h) and sub-acute (11 days) effects of oral (p.o.) and intraperitoneal (i.p.) administration of HdAE and BuE of A. elburzense bulbs in different doses were evaluated on blood glucose levels of normal and streptozotocin (STZ, 55 mg/kg body weight)-induced diabetic rats. Glibenclamide (1 mg/kg b.w.) was used as reference drug. Sub-acute treatment with HdAE for 11 days reduced significantly blood glucose levels in diabetic rats (at least P<0.05), while BuE was effective only following i.p. administration (P<0.01). Acute administration did not reduce blood glucose level in normal and diabetic animals. It is concluded that HdAE of A. elburzense exhibited a significant antihyperglycemic activity following chronic administration. These results provide evidence for potential use of A. elburzense in diabetes mellitus considering the fact that this plant is endemic to a location of Iran where diabetes is a high prevalence disorder.

Pharmaceutical and nutraceutical effects of Pinus pinaster bark extract

In everyday life, our body generates free radicals and other reactive oxygen species which are derived either from the endogenous metabolic processes (within the body) or from external sources. Many clinical and pharmacological studies suggest that natural antioxidants can prevent oxidative damage. Among the natural antioxidant products, Pycnogenol(®) (French Pinus pinaster bark extract) has been received considerable attention because of its strong free radical-scavenging activity against reactive oxygen and nitrogen species. P. pinaster bark extract (PBE) contains polyphenolic compounds (these compounds consist of catechin, taxifolin, procyanidins of various chain lengths formed by catechin and epicatechin units, and phenolic acids) capable of producing diverse potentially protective effects against chronic and degenerative diseases. This herbal medication has been reported to have cardiovascular benefits, such as vasorelaxant activity, angiotensin-converting enzyme inhibiting activity, and the ability to enhance the microcirculation by increasing capillary permeability. Moreover, effects on the immune system and modulation of nitrogen monoxide metabolism have been reported. This article provides a brief overview of clinical studies describing the beneficial and health-promoting effects of PBE.

Pre-marriage prevention of thalassaemia: report of a 100,000 case experience in Isfahan

BACKGROUND

Iran like other middle east countries has a large number of major thalassaemics. Due to religious restrictions on abortion, the routine prevention of the birth of thalassaemic children by this means is not possible. The aim of this study is to describe an alternative means to prevent the birth of thalassaemic children.

METHODS

From January 1993 to January 1996, 10,000 people preparing for marriage were screened for the thalassaemia trait, using CBC and HbA2 level measurement. High risk couples were referred for further consultation regarding the disease and the means of its prevention. The proposed actions of the couples regarding thalassaemia prevention were evaluated immediately after consultation and then re-evaluated three months later.

RESULT

After the project had been running for three years the average of high risk couple initially deciding not to marry was 90% and no new cases of thalassemia were detected in the children of the screened population.

CONCLUSION

Where both members of the couple were trait-positive their preferred choice was not to marry, rather than to marry and use other or no methods of preventing a thalassemia affected child being born to them. Cultural and religious ideas can affect such decisions and in some Islamic countries the establishment and use of a genetic counselling centre can help prevent most of new thalassaemia cases.