The use of herbal medicinal products and supplements has increased tremendously over the past three decades with not less than 80% of people worldwide relying on them for some part of primary health care. Although therapies involving these agents have shown promising potential with the efficacy of a good number of herbal products clearly established, many of them remain untested and their use are either poorly monitored or not even monitored at all. The consequence of this is an inadequate knowledge of their mode of action, potential adverse reactions, contraindications and interactions with existing orthodox pharmaceuticals and functional foods to promote both safe and rational use of these agents. Since safety continues to be a major issue with the use of herbal remedies, it becomes imperative, therefore, that relevant regulatory authorities put in place appropriate measures to protect public health by ensuring that all herbal medicines are safe and of suitable quality. This review discusses toxicity related-issues and major safety concerns arising from the use of herbal medicinal products and also highlights some important challenges associated with effective monitoring of their safety.

/pdf/the-growing-use-of-herbal-medicines-issues-relating-to-1ckeueyb3l.pdf

The growing use of herbal medicines: issues relating to adverse reactions and challenges in monitoring safety

Chemical studies of anthocyanins: A review

Phenolics and polyphenolics in foods, beverages and spices: Antioxidant activity and health effects – A review

Quantification of biological or biochemical processes are of utmost importance for medical, biological and biotechnological applications. However, converting the biological information to an easily processed electronic signal is challenging due to the complexity of connecting an electronic device directly to a biological environment. Electrochemical biosensors provide an attractive means to analyze the content of a biological sample due to the direct conversion of a biological event to an electronic signal. Over the past decades several sensing concepts and related devices have been developed. In this review, the most common traditional techniques, such as cyclic voltammetry, chronoamperometry, chronopotentiometry, impedance spectroscopy, and various field-effect transistor based methods are presented along with selected promising novel approaches, such as nanowire or magnetic nanoparticle-based biosensing. Additional measurement techniques, which have been shown useful in combination with electrochemical detection, are also summarized, such as the electrochemical versions of surface plasmon resonance, optical waveguide lightmode spectroscopy, ellipsometry, quartz crystal microbalance, and scanning probe microscopy. The signal transduction and the general performance of electrochemical sensors are often determined by the surface architectures that connect the sensing element to the biological sample at the nanometer scale. The most common surface modification techniques, the various electrochemical transduction mechanisms, and the choice of the recognition receptor molecules all influence the ultimate sensitivity of the sensor. New nanotechnology-based approaches, such as the use of engineered ion-channels in lipid bilayers, the encapsulation of enzymes into vesicles, polymersomes, or polyelectrolyte capsules provide additional possibilities for signal amplification. In particular, this review highlights the importance of the precise control over the delicate interplay between surface nano-architectures, surface functionalization and the chosen sensor transducer principle, as well as the usefulness of complementary characterization tools to interpret and to optimize the sensor response.

/pdf/electrochemical-biosensors-sensor-principles-and-5i1lr0kwi6.pdf

Electrochemical Biosensors - Sensor Principles and Architectures

A critical review of methods for characterisation of polyphenolic compounds in fruits and vegetables.

Analysis and biological activities of anthocyanins.

Arrays of highly ordered n-type silicon nanowires (SiNW) are fabricated using complementary metal-oxide semiconductor (CMOS) compatible technology, and their applications in biosensors are investigated. Peptide nucleic acid (PNA) capture probe-functionalized SiNW arrays show a concentration-dependent resistance change upon hybridization to complementary target DNA that is linear over a large dynamic range with a detection limit of 10 fM. As with other SiNW biosensing devices, the sensing mechanism can be understood in terms of the change in charge density at the SiNW surface after hybridization, the so-called "field effect". The SiNW array biosensor discriminates satisfactorily against mismatched target DNA. It is also able to monitor directly the DNA hybridization event in situ and in real time. The SiNW array biosensor described here is ultrasensitive, non-radioactive, and more importantly, label-free, and is of particular importance to the development of gene expression profiling tools and point-of-care applications.

Silicon Nanowire Arrays for Label-Free Detection of DNA

The main objective of this paper is to review recent advances in plant drug research and developments in orchid study, in an attempt to provide useful references for plant drug studies. Plants have been used as medicine for millennia. Out of estimated 250 000 to 350 000 plant species identified so far, about 35 000 are used worldwide for medicinal purposes. It has been confirmed by WHO that herbal medicines serve the health needs of about 80 percent of the world's population; especially for millions of people in the vast rural areas of developing countries. Meanwhile, consumers in developed countries are becoming disillusioned with modern healthcare and are seeking alternatives. The recent resurgence of plant remedies results from several factors: 1) the effectiveness of plant medicines; 2) the side effect of most modern drugs; and 3) the development of science and technology. It has been estimated that in the mid-1990s over 200 companies and research organizations worldwide are screening plant and animal compounds for medicinal properties. Actually, several important drugs used in modern medicine have come from medicinal plant studies, eg, taxol/paclitaxel, vinblastine, vincristine, topotecan, irinotecan, etoposide, teniposide, etc. As for drugs derived from orchids, some novel discoveries, both in phytochemical and pharmacological properties, were reported by some universities. However, studies on plants are very limited. Only about a third of the million or so species of higher plants have been identified and named by scientists. Of those named, only a tiny fraction has been studied. Nowadays the linking of the indigenous knowledge of medicinal plants to modern research activities provides a new approach, which makes the rate of discovery of drugs much more effective than with random collection.

Recent advances in traditional plant drugs and orchids.

A nanogapped microelectrode-based biosensor array is fabricated for ultrasensitive electrical detection of microRNAs (miRNAs). After peptide nucleic acid (PNA) capture probes were immobilized in nanogaps of a pair of interdigitated microelectrodes and hybridization was performed with their complementary target miRNA, the deposition of conducting polymer nanowires, polyaniline (PAn) nanowires, is carried out by an enzymatically catalyzed method, where the electrostatic interaction between anionic phosphate groups in miRNA and cationic aniline molecules is exploited to guide the formation of the PAn nanowires onto the hybridized target miRNA. The conductance of the deposited PAn nanowires correlates directly to the amount of the hybridized miRNA. Under optimized conditions, the target miRNA can be quantified in a range from 10 fM to 20 pM with a detection limit of 5.0 fM. The biosensor array is applied to the direct detection of miRNA in total RNA extracted from cancer cell lines.

Detection of MicroRNAs using target-guided formation of conducting polymer nanowires in nanogaps.

A versatile method, based on the metallization of DNA strands, is developed to prepare palladium nanoparticles on indium tin oxide (ITO) coated glass surface. Resulted palladium nanoparticles are distributed along the DNA strands and their size is controllable in the range of 10–100 nm. This is contrast to the branched palladium aggregates formed on bare ITO surface. When used as an electrochemical sensor, the nanoparticles show strong catalytic activity for the reduction of hydrogen peroxide and the oxidation of ascorbic acid, respectively. Higher catalytic activity is observed with the nanoparticles formed on double-stranded DNA (dsDNA) templates than those on single-stranded DNA (ssDNA) templates.

Jin-Ming Kong

Papers

Analysis and biological activities of anthocyanins.

Silicon Nanowire Arrays for Label-Free Detection of DNA

Recent advances in traditional plant drugs and orchids.

Detection of MicroRNAs using target-guided formation of conducting polymer nanowires in nanogaps.

DNA-templated preparation of palladium nanoparticles and their application