Phytochemical screening and preliminary clinical trials of the aqueous extract mixture of Andrographis paniculata (Burm. f.) Wall. ex Nees and Syzygium polyanthum (Wight.) Walp leaves in metformin treated patients with type 2 diabetes
Objective
Bay leaf, one of the plants in Indonesia that has been shown to have activities to reduce cholesterol in the blood. HMG-CoA Reductase inhibition is one of many mechanisms in lowering the level of cholesterol in the blood. Here, we reported the inhibitory activity of HMG-CoA Reductase of bay leaves ethanol extracts that we suspected to be the mechanism of action of bay leaves in reducing cholesterol in the blood. In this research we also investigated the correlation between the inhibitory activities, the total phenol content and antioxidant activities of bay leaves (
Syzygium polianthum
) ethanol extracts.
Methods
The inhibitory activity of HMG-CoA Reductase was determined kinetically at 340 nm using simvastatin as positive control.
In vitro
scavenging assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric ion reducing antioxidant power (FRAP), and beta-carotene method were used to determine the antioxidant activities. The total phenolic content was determined by Folin-Ciocalteu's method.
Results
The IC
50
of bay leaves ethanolic extract obtained by percolation and soxhlet extraction method towards HMG-CoA Reductase enzyme activity were 49.50 ± 0.700 μg/mL and 15.50 ± 0.707 μg/mL, respectively, while the IC
50
of simvastatin was 0.00238 ± 0.00004 μg/mL. The antioxidant activity and total phenolic content of bay leaves ethanolic extract obtained by Soxhlet extraction method was higher compared to the percolation method (DPPH and beta-carotene assay results). The 3D linear analysis showed that there was a high correlation between the inhibition activities of HMG-CoA Reductase pattern of both extract types and the total phenol pattern and also the antioxidant pattern of these extracts.
Conclusion
The result showed that the bay leaves ethanolic extract have a potent activity to reduce the cholesterol serum level by inhibition of HMG-CoA Reductase activity. The activity was due to the phenolic compounds in the extracts as well as the antioxidant activity of the extracts.
The hexane, ethyl acetate, ethanol and water extracts of Synedrella nodiflora (L.) Gaertn. (Asteraceae) were assessed for their antibacterial and antioxidant capacities. The antioxidant capacities were evaluated using the ferric reducing antioxidant power (FRAP) and β-carotene bleaching assays. The antimicrobial activities were assessed using the classical pour-plate disc diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and death kinetic assays, against six bacterial strains. The ethanol extract displayed significant antioxidant capacities both in the FRAP and β-carotene bleaching assays. The ethanol extract abrogated the growth of all the bacteria tested. Folin-Ciocalteu and aluminium chloride spectrometry assays indicated the presence phenolic compounds, including flavonoids in the ethanol extract.
The aim of this study was to investigate the antioxidant and anti-inflammatory potentials of crude extracts of Lopholaena coriifolia (Sond.) E. Phillips & C.A. Sm. and its isolated compounds. Separation and structure elucidation of Lopholaena coriifolia (Sond.) E. Phillips & C.A. Sm. were conducted using chromatographic and spectroscopic method. The antioxidant activities of the extracts in this study were determined by the ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene bleaching assays meanwhile the anti-inflammatory activity was evaluated using the 5-lipoxygenase assay. Seven known compounds quercetin 3-O-glucoside (1), naringenin 7-O-glucoside (2), seneciphylline-O-glucoside (3), chrysoeriol (4), retrorsine (5), adonifiline (6) and 5,4'-di-O-methyl alpinumisoflavone (7) were isolated from ethanol extract of Lopholaena coriifolia (Sond.) E. Phillips & C.A. Sm. The ethanol and water extracts of Lopholaena coriifolia (Sond.) E. Phillips & C.A. Sm. elicited potent antioxidant and anti-inflammatory properties. Amongst the isolated compounds quercetin 3-O-glucoside gave strong antioxidant activity and adonifiline strongly inhibited 5-lipoxygenase activity.
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