Quantitative HPLC analysis of two key flavonoids and inhibitory activities against aldose reductase from different parts of the Korean thistle, Cirsiummaackii

Previously, the correlation between antioxidant activity and HPLC profiles of several Korean thistles has been recognized. In our ongoing study of the comparative evaluation of Korean thistles, we chose Cirsiummaackii to assess the antioxidant and aldose reductase (AR) inhibitory activities of its varying parts, including the leaves, roots, stems, and flowers, along with two major components, luteolin 5-O-β-d-glucopyranoside (1) and the aglycone luteolin (2). In order to determine selective and efficient usage of the individual parts, HPLC quantitative analysis of the two key flavonoids of each C. maackii part has been performed for the first time. From the results of the comparative evaluation between the oxidative stress-related diabetic complications and quantitative phytochemical analysis from various parts of C. maackii, the content of 1 and 2 might contribute to the antioxidant and AR inhibitory activities of this thistle, clearly suggesting their potential for use in the development of therapeutic or preventive agents for diabetic complications and oxidative stress-related diseases. Furthermore, our present study will pave the way of the guidelines for the efficacy and differentiation and standardization of individual parts of this herbal material, and as such, this bioactive thistle could serve as an alternative source of 1 and 2.     

Diabetes complications and their potential prevention: Aldose reductase inhibition and other approaches

Despite recent advances both in the chemistry and molecular pharmacology of antidiabetic drugs, diabetes still remains a life-threatening disease, which tends to spread all over the world. The clinical profile of diabetic subjects is often worsened by the presence of several long-term complications, namely neuropathy, nephropathy, retinopathy, and cataract. Several attempts have been made to prevent or at least to delay them. The most relevant are reported in this review, including the development of compounds acting as aldose reductase inhibitors, anti-advanced glycation end-product drugs, free radical scavengers, vasoactive agents, essential fatty acid supplementation, and neurotropic growth factors. © 1999 John Wiley & Sons, Inc. Med Res Rev, 19, No. 1, 3–23, 1999.     

Novel aldose reductase inhibitors: a patent survey (2006 – present)

Introduction: Initially studied for its central role in the pathogenesis of chronic diabetic complications, aldose reductase (ALR2) gains more attention over the years as its implication in inflammatory diseases is being established, along with the therapeutic potential of its inhibitors.

Areas covered: Reviewing the patents that were published since 2006, it is getting clear that the search for new chemical entities has subsided, giving rise to natural products and plant extracts with ALR2 inhibitory activity. Other aspects that were prominent were the search for proper forms of known inhibitors, in a way to improve their impaired physicochemical profile, as well as potential combination therapies with other compounds of pharmaceutical interest. On the spotlight were patents enhancing the therapeutic usage of aldose reductase inhibitors (ARIs) to various pathological conditions including cancer and inflammation-mediated diseases such as sepsis, asthma, and cancer.

Expert opinion: Although new chemical entities are scarcely registered and patented after many years of inconclusive clinical trials, the involvement of ALR2 to inflammatory pathologies might renew the interest in the field of ARIs.     

Extraction and identification of three major aldose reductase inhibitors from Artemisia montana

Aldose reductase inhibitors (ARIs) provide an important therapeutic and preventive opportunity against hyperglycemia associated diabetic complications. The methanolic extracts of 12 species from the genus Artemisia exhibited significant in vitro rat lens AR (RLAR) inhibitory activities with IC₅₀ values ranging from 0.51 to 13.45 μg/mL (quercetin, 0.64 μg/mL). Since the whole plant of Artemisia montana showed the highest RLAR inhibitory activity, bioassay-guided fractionation was performed to obtain ethyl acetate and n-butanol fractions. Repeated column chromatography of two active fractions, yielded fifteen compounds, including four chlorogenic acids (3,5-di-O-caffeoylquinic acid, chlorogenic acid, neochlorogenic acid, cryptochlorogenic acid), six flavonoids (apigenin, luteolin, quercetin, isoquercitrin, hyperoside, luteolin 7-rutinoside), and five coumarins (umbelliferone, scoparone, scopoletin, esculetin, and scopolin); their structures were confirmed by spectroscopic methods. 3,5-Di-O-caffeoylquinic acid and chlorogenic acid, as well as test flavonoids, displayed the most potent RLAR inhibitory activities with IC₅₀ values ranging from 0.19 to 5.37 μM. Furthermore, the HPLC profiles of the ethyl acetate and n-butanol fractions indicated that 3,5-di-O-caffeoylquinic acid, chlorogenic acid, and hyperoside, as major compounds, might play crucial roles in RLAR inhibition. The results suggest that A. montana and three key AR inhibitors therein would clearly be potential candidates as therapeutic or preventive agents for diabetic complications.     

Utility of multiplex real-time PCR for diagnosing paediatric acute respiratory tract infection in a tertiary care hospital

BackgroundAcute respiratory infections (ARIs) are responsible for considerable morbidity and mortality among children all over the world. Many of the etiologic agents of the infections especially viral go undiagnosed for lack of requisite facility and the cost factors. We have used a commercially available platform for diagnosis of ARIs in children receiving inpatient and outpatient services in a tertiary care centre.MethodsThe framework of the study was prospective and observational. In this study, clinical samples of children suffering from ARIs were subjected to real-time multiplex PCR targeting both viral and bacterial pathogens.ResultsOf 94 samples received at our centre (49 male and 45 female), the positivity for respiratory pathogens was detected in 50 (53.19%) samples. Clinical symptoms of patients and age distribution have been elaborated in text. A single pathogen (n = 29/50), two pathogens (15/50) and three pathogens (n = 6/50) were detected by multiplex RT-PCR. Of 77 isolates detected, maximum numbers were of human rhinovirus (HRV) (n = 14) (18.18%) Streptococcus pneumoniae (n = 14) (18.18%) followed by Staphylococcus aureus (n = 10) (12.98%).ConclusionThe epidemiology of ARIs considering viral etiologies is poorly understood due to less number of studies especially in Indian subcontinent. The advent of latest advanced molecular methods has made it possible to identify common respiratory pathogens and has contributed to cover the gap in existing knowledge.