RESUMO
Convolvulus arvensis L. is an evergreen herb growing in various regions of Pakistan. Despite of several medicinal properties associated to this herb, it was not investigated scientifically for its bioactive compounds and detailed pharmaceutical properties. Therefore, its methanolic extract was divided into hexane (CA-H), chloroform (CA-C), ethyl acetate (CA-E) and butanol (CA-B) soluble fractions. CA-H and CA-C were found rich in phenolics (30.73±0.63 and 20.15±0.59â mg GAE/g of the extract, respectively), and the same fractions exhibited significant antioxidant activities (DPPH: 5.23±0.11 & 12.34±0.17â mg TE/g extract, respectively; ABTS: 36.82±0.04 & 56.74±0.61â mg TE/g extract, respectively). Also in CUPRAC activity assay, CA-H and CA-C exhibited highest activities as 87.30±0.46 and 56.74±0.61â mg TE/g extract, respectively, while CA-C was most active in FRAP activity assay with value of 40.21±2.19â mg TE/g extract. Total antioxidant capacity (1.23±0.033â mmol TE/g extract) was also found higher for CA-C, while CA-H activity was also comparable, however, CA-H showed higher metal chelating activity (22.74±0.001â mg EDTAE/g extract) than that of CA-C (17.55±0.22â mg EDTAE/g extract). These activities clearly revealed a direct relation between antioxidant potential and phenolic contents of CA-H and CA-C. In AChE and BChE inhibitory assay, CA-H and CA-E showed better inhibition (AChE: 8.24±0.77 & 4.46±0.007â mg GALAE/g extract; BChE: 5.40±0.02 & 1.92±0.24â mg GALAE/g extract) as compared to other fractions, whereas, against tyrosinase, CA-B was most active (37.35±0.53â mg KAE/g extract). CA-H and CA-C also showed higher inhibitory potential (0.98±0.08 & 0.58±0.01â mmol ACAE/g extract) against α-Amylase; while against α-Glucosidase, CA-E was the most active fraction. UHPLC/MS analysis of the methanolic extract of C. arvensis disclosed the presence of 62 compounds as sterols, triterpenes, flavonoids, fatty acids, alkaloids and coumarins. In Multivariate Analysis, the total phenolic contents were correlated strongly with all antioxidant assays except FRAP and DPPH. Regarding enzyme inhibitory properties, only AChE, BChE and α-amylase were correlated with the total phenolic contents in the extracts. Docking analyses confirmed these findings, as identified compounds had high binding free energy and inhibition constants with the enzymes studied. It was finally concluded that C. arvensis is a potential industrial crop, which can be a component of nutraceuticals and functional foods, if evaluated for its toxicity.
Assuntos
Antioxidantes , Convolvulus , Antioxidantes/química , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Cromatografia Líquida de Alta Pressão , alfa-Amilases , Fenóis/química , Metanol/química , Análise Multivariada , Indústria Farmacêutica , Recursos Naturais , Compostos Fitoquímicos/farmacologia , Compostos Fitoquímicos/análiseRESUMO
Over the last decade, it has become clear that antimicrobial drugs are losing their effectiveness due to the evolution of pathogen resistance. There is therefore a continuing need to search for new antibiotics, especially as new drugs only rarely reach the market. Natural products are both fundamental sources of new chemical diversity and integral components of today's pharmaceutical compendium, and the aim of this review is to explore and highlight the diverse natural products that have potential to lead to more effective and less toxic antimicrobial drugs. Although more than 300 natural metabolites with antimicrobial activity have been reported in the period 2000-2008, this review will describe only those with potentially useful antimicrobial activity, viz. with MICs in the range 0.02-10 microg mL(-1). A total of 145 compounds from 13 structural classes are discussed, and over 100 references are cited.