Phenolic content and in vitro inhibitory effects on oxidation and protein glycation of some Thai medicinal plants

Article (PDF Available)inPakistan journal of pharmaceutical sciences 23(4):403-8 · October 2010with539 Reads
Source: PubMed
Abstract
Fifteen medicinal plant extracts were investigated for: total phenolic content and free radical scavenging effect by DPPH and ABTS assays; anti-lipid peroxidation activity by TBARS; and for antiglycation activity. The results revealed that the total phenolic content showed good correlation with free radical scavenging by ABTS (r = 0.721) and anti-lipid peroxidation by TBARS (r = -0.659), but showed no correlation with antiglycation. Three extracts from Tamarindus indica, Camellia sinensis and Artocarpus lakoocha demonstrated a significant antioxidant effect, and also showed a promising antiglycation effect. The IC50 (mg/ml) were 0.9-0.16 for the DPPH method; TEAC values (mg Trolox/mg sample) of 1.72-2.83 for the ABTS method; IC50 (mg/ml) of 0.64-1.22 for the TBARS method; and IC50 ranging from 0.01 to 3.20 for the antiglycation method. These three herbs were found to possess effective antioxidant and antiglycation activities, and could be further developed for use in anti-aging cosmetics.
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    • "Glycation is a non-enzymatic spontaneous reaction between reducing sugar and coexisting protein. This reaction undergoes formation of labile Schiff base that rearranges to a stable Amadori product, which is followed by a complex cascade of reactions leading to the formation of advanced glycation end products (AGEs) [23][24][25][26]. Glycation depends on the generation of reactive oxygen species through trace amounts of redox active metal ions [27] and on the degree and duration of hyperglycemia in vivo [28]. "
    [Show abstract] [Hide abstract] ABSTRACT: The present study was aimed to synthesize and characterize a series of Pd(II)-benzohydrazide complexes with subsequent high throughput screening to seek their effects as enzyme inhibitors and antiglycating agents. Based on complete characterization via elemental (CHN, Pd) analysis, physical (conductivity, magnetic moment) measurements and spectral (FT-IR, 1H-NMR, 13C-NMR) techniques, all Pd(II) complexes were identified as diamagnetic, neutral and orienting in trans square planar geometry with general formula [PdL2Cl2]. The benzohydrazide (L) in these complexes depicts monodentate behavior, providing terminal amino nitrogen as a donor atom. Compared to inactive precursors (free benzohydrazides and Pd2+), almost all Pd(II) complexes showed in vitro antiglycation activity, illustrating the potential role of resulting complexes in the suppression of diabetes and related disorders. The presence of free carbonyl group in complexes has been recognized as possible cause of antiglycation. This study also indicated Pd(II) compounds as far more superior inhibitors of urease and phosphodiesterase-I than parent ligands; many of them exhibited inhibitions equivalent or even greater than the standard inhibitors (thiourea, urease; EDTA, phosphodiesterase), which shows their potential use in future in the control of peptic ulcer and arthritis, respectively. The structure activity relationship (SAR) study demonstrated that complexation, steric hindrance, position of substituents, electron density around metal centre, hydrogen bonding and coordination mode of complexed ligands play prime role in modulating the biological activities of complexes.
    Full-text · Article · Nov 2016
    Qurrat-ul-AinSaima RasheedSaima RasheedMohammad Mahroof-TahirMohammad Mahroof-Tahir+3 more authors ...Sana MustafaSana Mustafa
    • "The results of the FRAP, DPPH and LPO assays revealed that all tested Scutellaria extracts have potent antioxidant activity. S. alpina extracts demonstrated similar EC 50 values as Zingiber officinale (75 µg/mL), while S. altissima was comparable to Myristica fragrans (100 µg/mL) [16] and Camelia sinensis (100 µg/mL) [17]. The antioxidant properties of Scutellaria plants can be explained by the presence of different flavones and the phenylethanoid glycoside verbascoside, also known as acteoside. "
    [Show abstract] [Hide abstract] ABSTRACT: Methanolic extracts from the aerial parts and roots of two Scutellaria species, S. alpina and S. altissima, and five polyphenols from these plants demonstrated a significant ability to inhibit the formation of advanced glycation end-products (AGE) in vitro. S. alpina, which is richer in polyphenolic compounds, had strong antiglycation properties. These extracts demonstrated also high activity in the FRAP (ferric-reducing antioxidant power), antiradical (DPPH) and lipid peroxidation inhibition assays. Among the pure compounds, baicalin was the strongest glycation inhibitor (90.4% inhibition at 100 μg/mL), followed by luteolin (85.4%). Two other flavone glycosides had about half of this activity. Verbascoside was similar to the reference drug aminoguanidine (71.2% and 75.9%, respectively). The strong correlation observed between AGE inhibition and total flavonoid content indicated that flavonoids contribute significantly to antiglycation properties. A positive correlation was also observed between antiglycative and antioxidant activities. The studied skullcap species can be considered as a potential source of therapeutic agents for hyperglycemia-related disorders.
    Full-text · Article · Jun 2016
    • "Previous studies have found the correlations between total phenolic compounds and the inhibitory effect on AGE formation of different extracts [39, 43]. Povichit et al. described negative correlation that medicinal plants exhibited high antiglycation activity while they had low phenolic content [44]. The present findings indicate that total phenolic compounds strongly correlate with the MG-trapping abilities of the extract, whereas they demonstrate moderate association with the inhibition of MG-derived AGEs. "
    [Show abstract] [Hide abstract] ABSTRACT: Background Methylglyoxal (MG) is one of the most reactive glycating agents, which result the formation of advanced glycation end-products (AGEs) that have been implicated in the progression of age-related diseases. Inhibition of MG-induced AGE formation is the imperative approach for alleviating diabetic complications. The objective of this study was to investigate the MG-trapping abilities of herbal medicines and their inhibitory activities on the formation of MG-derived AGEs. Methods The aqueous extract of herbal medicines was measured for the content of total phenolic compounds and the antioxidant activity by Folin-Ciocalteu assay and the 1,1-diphenyl 2-picrylhydrazyl (DPPH) radical scavenging activity, respectively. The extracts were investigated the MG-trapping ability by high performance liquid chromatography (HPLC). The extracts were incubated with BSA and MG at 37 °C for 1 day. The formation of MG-derived AGEs was measured. Results Total phenolic compounds of eleven herbal medicines showed marked variations, ranging from 12.16 to 272.36 mg gallic acid equivalents/g extract. All extracts (1 mg/mL) markedly exhibited the DPPH radical scavenging activity (0.31–73.52 %) and the MG-trapping abilities (13.97–58.97 %). In addition, they also inhibited the formation of MG-derived AGEs by 4.01–79.98 %. The results demonstrated that Rhinacanthus nasutus, Syzygium aromaticum, and Phyllanthus amarus were the potent inhibitors against the formation of MG-derived AGEs. The positive correlations between the contents of phenolics and % MG trapping (r = 0.912, p < 0.01) and % inhibition of MG-derived AGEs (r = 0.716, p < 0.01) were observed in the study. Furthermore, there was a moderate positive correlation between % MG trapping and % inhibition of MG-derived AGEs (r =0.584, p < 0.01). Conclusions Rhinacanthus nasutus, Syzygium aromaticum, and Phyllanthus amarus could reduce the formation of MG-derived AGEs through their MG-trapping abilities. These findings are relevant for focusing on potential herbal medicines to prevent or ameliorate AGE-mediated diabetic complications.
    Full-text · Article · Dec 2015
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