Evaluation of 5α-reductase inhibitory activity of certain herbs useful as antiandrogens.

This study demonstrates 5α-reductase inhibitory activity of certain herbs useful in the management of androgenic disorders. Ganoderma lucidum (Curtis) P. Karst (GL), Urtica dioica Linn. (UD), Caesalpinia bonducella Fleming. (CB), Tribulus terrestris Linn. (TT), Pedalium murex Linn. (PM), Sphaeranthus indicus Linn. (SI), Cuscuta reflexa Roxb. (CR), Citrullus colocynthis Schrad. (CC), Benincasa hispida Cogn. (BH), Phyllanthus niruri Linn. (PN) and Echinops echinatus Linn. (EE) were included in the study. Petroleum ether, ethanol and aqueous extracts of these herbs were tested for their 5α-reductase inhibitory activity against the standard 5α-reductase inhibitor, finasteride. A biochemical method to determine the activity of 5α-reductase was used to evaluate the inhibition of different extracts to the enzyme. The optical density (OD) value of each sample was measured continuously with ultraviolet spectrophotometer for the reason that the substrate NADPH has a specific absorbance at 340 nm. As the enzyme 5α-reductase uses NADPH as a substrate, so in the presence of 5α-reductase inhibitor, the NADPH concentration will increase with the function of time. This method thus implicates the activity of 5α-reductase. The method proved to be extremely useful to screen the herbs for their 5α-reductase inhibitory potential. GL, UD, BH, SI and CR came out to be promising candidates for further exploring their antiandrogenic properties.

Ganoderma lucidum is an inhibitor of testosterone-induced prostatic hyperplasia in rats.

The aim of the present study was to find out whether Ganoderma lucidum (GL) can be used as a clinically effective medicine for the management of prostatic hyperplasia. In vitro studies were conducted to assess the 5α-reductase inhibitory potential of GL. A biochemical marker viz. ß-sitosterol was identified and characterised in the extracts utilising high-performance thin-layer chromatography. Testosterone (3 mg kg(-1) s.c.) was administered to the rats along with the test extracts (10, 20 and 50 mg kg(-1) p.o.) and ß-sitosterol (10 and 20 mg kg(-1) p.o.) for a period of 28 days. Finasteride was used as a positive control (1 mg kg(-1) p.o.). GL extracts attenuated the increase in the prostate/body weight ratio induced by testosterone. Petroleum ether extract exhibiting the best activity. Ethanolic extract also exhibited significant activity. The urine output also improved significantly, which emphasise the clinical implications of the study. Testosterone levels measured weekly and prostate-specific antigen (PSA) levels measured at the end of the study also support our claims. The PSA levels decreased in the extract-treated groups, indicating their usefulness in the treatment of benign prostatic hyperplasia. Histological studies have shown a considerable improvement in the prostatic histoarchitecture in the extract-treated groups when compared to the testosterone-treated group.

Ameliorative effects of stinging nettle (Urtica dioica) on testosterone-induced prostatic hyperplasia in rats.

The present study investigated the effects of stinging nettle (Urtica dioica L.) (UD) on benign prostatic hyperplasia (BPH) induced by testosterone. In vitro studies were conducted to assess the 5α-reductase inhibitory potential of UD. Two biochemical markers viz., ß-sitosterol and scopoletin, were isolated and characterised in the extracts utilising High-performance thin layer chromatographic, FTIR, NMR and overlain UV spectral studies. Hyperplasia was induced in rats by subcutaneous administration of testosterone (3 mg kg(-1) s.c.) for 28 days in all the groups except the vehicle-treated group. Simultaneous administration of petroleum ether and ethanolic extracts (10, 20 and 50 mg kg(-1) p.o.) and isolated ß-sitosterol (10 and 20 mg kg(-1) p.o.) was undertaken. Finasteride was used as a positive control (1 mg kg(-1) p.o.). Measurement of prostate/body weight ratio, weekly urine output and serum testosterone levels, prostate-specific antigen levels (on day 28) and histological examinations carried out on prostates from each group led us to conclude that UD can be used as an effective drug for the management of BPH.

Terahertz spectroscopy of plasmonic fractals.

We use terahertz time-domain spectroscopy to study the transmission properties of metallic films perforated with aperture arrays having deterministic or stochastic fractal morphologies ("plasmonic fractals"), and compare them with random aperture arrays. All of the measured plasmonic fractals show transmission resonances and antiresonances at frequencies that correspond to prominent features in their structure factors in k space. However, in sharp contrast to periodic aperture arrays, the resonant transmission enhancement decreases with increasing array size. This property is explained using a density-density correlation function, and is utilized for determining the underlying fractal dimensionality, D(<2). Furthermore, a sum rule for the transmission resonances and antiresonances in plasmonic fractals relative to the transmission of the corresponding random aperture arrays is obtained, and is shown to be universal.

Spectrofluorimetric Estimation of Scopoletin in Evolvulus alsinoides Linn. and Convulvulus pluricaulis Choisy.

A simple sensitive spectrofluorimetric method was developed for the analysis of total coumarins calculated as scopoletin in the plants Evolvulus alsinoides and Convulvulus pluricaulis. The fluorescent nature of scopoletin proved to be of immense value in the development of the spectrofluorimetric method. The excitation and emission wavelengths for scopoletin were 430 nm and 460 nm respectively and the instrument was Shimadzu RF 5301 PC spectrofluorophotometer. The method was validated in terms of linearity, accuracy and precision. The proposed spectrofluorimetric method provides a faster and cost effective qualitative and quantitative control for routine analysis of scopoletin in Evolvulus alsinoides and Convulvulus pluricaulis and their formulations.

Nonlinear optical generation and detection of ultrashort electrical pulses in transmission lines.

The nonlinear optical generation and detection of subpicosecond electrical pulses on coplanar transmission lines is demonstrated. The electrical pulses are generated by optical rectification of ultrashort optical pulses and detected by electro-optic sampling. Both processes are the result of a second-order nonlinear optical response that occurs in the same poled polymer medium. A bipolar temporal waveform with a FWHM duration of 180 fs for the positive lobe that was measured after a propagation distance of 125 mum was observed. Pulse broadening was minimized by careful attention to the device structure.

Single-shot measurement of terahertz electromagnetic pulses by use of electro-optic sampling.

We demonstrate a simple scheme for capturing the temporal waveforms of a freely propagating terahertz electromagnetic transient in a single shot. The method relies on electro-optic sampling in a noncollinear geometry for the terahertz radiation and the visible probe beam, coupled with multichannel detection. The approach provides time resolution that is comparable to that of conventional electro-optic sampling measurements.

Measurement of the vector character of electric fields by optical second-harmonic generation.

We present a scheme for the determination of the vector nature of an electric field by optical second-harmonic generation. We demonstrate the technique by mapping the two-dimensional electric-field vector of a biased transmission line structure on silicon with a spatial resolution of ~10mum .

Detection of freely propagating terahertz radiation by use of optical second-harmonic generation.

We report the application of electric-field-induced optical second-harmonic generation as a new technique for measuring the field of freely propagating terahertz radiation. Using silicon as the nonlinear medium, we demonstrate subpicosecond time resolution and a sampling signal that varies linearly with the terahertz electric field. This approach, which is attractive for centrosymmetric media, permits a significantly broadened class of materials to be exploited for free-space sampling measurements.

Generation of subpicosecond electrical pulses by optical rectification.

We describe the generation of subpicosecond electrical pulses by optical rectification of ultrashort optical pulses. The electrical pulses are generated by the second-order nonlinear response of a LiTaO(3) crystal bonded to a coplanar transmission line. A bipolar temporal waveform with a width of 875 fs was measured after a propagation distance of 175mum . This pulse width was limited by the response time of the photoconductive sampler. We observed both broadening and amplitude reduction in the temporal waveform owing to propagation.