A thin-layer chromatography-bioautographic method for detecting dipeptidyl peptidase IV inhibitors in plants

A thin-layer chromatography (TLC)-bioautographic method was developed with the aim to detect dipeptidyl peptidase IV (DPP IV) inhibitors from plant extracts. The basic principle of the method is that the enzyme (DPP IV) hydrolyzes substrate (Gly-Pro-p-nitroaniline) into p-nitroaniline (pNA), which diazotizes with sodium nitrite, and then reacts with N-(1-naphthyl) ethylenediamine dihydrochloride in turn to form a rose-red azo dye which provides a rose-red background on the TLC plates. The DPP IV inhibitors showed white spots on the background as they blocked enzymolysis of the substrate to produce pNA. The method was validated with respect to selectivity, sensitivity, linearity, precision, recovery, and stability after optimizing key parameters including plate type, time and temperature of incubation, concentration of substrate, enzyme and derivatization reagents, and absorption wavelength. The results showed good lineary within amounts over 0.01–0.1 μg range for the positive control, diprotin A, with the coefficient of determination (r2) = 0.9668. The limits of detection (LOD) and quantification (LOQ) were 5 and 10 ng, respectively. The recoveries ranged from 98.9% to 107.5%. The averages of the intra- and inter-plate reproducibility were in the range of 4.1–9.7% and 7.6–14.7%, respectively. Among the nine methanolic extracts of medicinal herbs screened for DPP IV inhibitors by the newly developed method, Peganum nigellastrum Bunge was found to have one white active spot, which was then isolated and identified as harmine. By spectrophotometric method, harmine hydrochloride was found to have DPP-IV inhibitory activity of 32.4% at 10 mM comparing to that of 54.8% at 50 μM for diprotin A.

How women use and experience western herbal practice for distress: implications for health care and self-management approaches.

Introduction: In the UK, common mental health disorders account for one in five of all work days lost, and cost employers £25bn each year. Herbal medicine has been shown to potentially be of use for mental distress, including conditions like anxiety. In 2008, 35% of British adults surveyed claimed to have used herbal medicine at some stage, the majority of whom were women. However, there is little research into how the users of western herbal medicine (WHM) experience the practice of herbal medicine, or how these experiences may change over time. Our research is studying women in the south-east of the UK who are suffering from distress (either as a primary complaint, or associated with another condition) who are seeking the services of a herbalist who practices WHM. Aim: To investigate the experiences of western herbal practice by women who are suffering with distress. Methods: The study is using semi-structured interviews of around thirty women, to elicit patient narratives at two time points. Thematic analysis is being used to consider how distressed women perceive and experience their distress, their reasons for using WHM, what contribution the women perceive the consultation and treatment with WHM may or may not make to their wellbeing, and whether their experiences change over time. Currently, sixteen women have been interviewed, and a preliminary thematic analysis has commenced. Results: Preliminary finding suggest that not only do women internalise their distress, but that they are surprisingly isolated in how they deal with it, whilst some also express social embarrassment about their experiences. The women perceived that their distress is not always considered seriously from their medical practitioners’ point of view. These women are drawn to herbalists not only in a search for effective treatment, but also to be given time to have their story heard, to form a collaborative relationship, and to attempt to regain some control of their life. The herbal treatment is valued due to its perceived naturalness, and reduced risk of adverse side effects. Nevertheless, WHM is just one of a number of self-care strategies that women utilise to help manage their distress. Discussion: Effective treatment is not only dependent upon the herbs, but also upon an effective therapeutic relationship. Feeling that the herbalist hears their story, provides a treatment plan that is individually tailored to the patient, and is available (even outside of the consultation) are all important in helping to establish this relationship.