Evaluation of antioxidants activity of Momordica charantia using LC-MS metabolomics approach

Objectives: The present study was design to identify the significant biomarkers from M.charantia that possessing antioxidant activity using liquid chromatography-mass spectrometry (LC-MS) based metabolomics approaches. Design and method: Initially, the fruit was extracted by soaking in different solvents with different concentrations of ethanol in water (0, 20, 40, 60, 80, 100%, v/v). Then, the extracts were tested for antioxidant activity using 1, 1-diphenyl-2 picrylhydrazyl (DPPH) and ferric reducing antioxidant power assay. LC-MS based metabolomics approach correlated with multivariate data analysis was applied to profile the bioactive compounds present in the extract. Results The 80% ethanol extract showed a high inhibitory activity on 1, 1-diphenyl-2 picrylhydrazyl (DPPH) radical and high ferric reducing antioxidant power, LC-MS based metabolomics approaches helped to identify several antioxidants in this extract such as ascorbic acid, margarolic acid, brevifolincarboxylic acid, quercetin 3-O-glycoside, kuguacin H, cucurbitacin E, 3-malonylmomordicin I, goyaglycoside G. Conclusion: The results of the present study shows possible antioxidants from M. charantia fruit can be identified Keywords: Momordica charantia, LCMS, Metabolomics, antioxidant, multivariate data analysis

Antioxidant effects of some selected flavonoids: a structure-activity relationship based study

Objective: To investigate the antioxidant and radical scavenging activities of some selected flavonoids with respect to identify key positions responsible for antioxidant effects as well as the effect of derivatisation on the antioxidative effects. Design and method: Antioxidant potential was evaluated using different sets of assays viz., rapid test by dot blot, 1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging, ABTS+ radical cation scavenging, ferric reducing antioxidant powder (FRAP) and xanthine oxidase inhibitory (XOI) assays. Results: It was determined that the total number and the configuration of hydroxyl group play an important role in regulating bioactivity of flavonoids in scavenging DPPH radical, ABTS+ radical cation and FRAP assays. Presence of catechol and the absence of C-2-C-3 double bond as well as ketonic group at C-4 reduced the xanthine oxidase inhibitory activity. Methylation and acetylation of hydroxyl groups at particular positions were also found to decrease the in vitro bioactivity of flavonoids. Conclusions: The results of this study will further help to understand the role of flavonoids as natural antioxidants which might facilitate in the development of nutritional products and semi synthetic analogs that retain substantial antioxidant capacity with minimal adverse effects. Keywords: Flavonoids; antioxidant activity; derivatisation, structure activity relationshi

Identification of α-glucosidase inhibitorsfrom Clinacanthus nutans leaf extract using liquid chromatography-mass spectrometry-based metabolomics and protein-ligand interaction with molecular docking

The present study used in vitro and in silico techniques, as well as the metabolomics approach to characterise α-glucosidase inhibitors from different fractions of Clinacanthus nutans. C. nutans is a medicinal plant belonging to the Acanthaceae family, and is traditionally used to treat diabetes in Malaysia. n-Hexane, n-hexane: ethyl acetate (1:1, v/v), ethyl acetate, ethyl acetate: methanol (1:1, v/v), and methanol fractions were obtained via partitioning of the 80% methanolic crude extract. The in vitro α-glucosidase inhibitory activity was analyzed using all the fractions collected, followed by profiling of the metabolites using liquid chromatography combined with mass spectrometry. The partial least square (PLS) statistical model was developed using the SIMCA P+14.0 software and the following four inhibitors were obtained: (1) 4,6,8-Megastigmatrien-3-one; (2) N-Isobutyl-2-nonen-6,8-diynamide; (3) 1′,2′-bis(acetyloxy)-3′,4′-didehydro-2′-hydro-β, ψ-carotene; and (4) 22-acetate-3-hydroxy-21-(6-methyl-2,4-octadienoate)-olean-12-en-28-oic acid. The in silico study performed via molecular docking with the crystal structure of yeast isomaltase (PDB code: 3A4A) involved a hydrogen bond and some hydrophobic interactions between the inhibitors and protein. The residues that interacted include ASN259, HID295, LYS156, ARG335, and GLY209 with a hydrogen bond, while TRP15, TYR158, VAL232, HIE280, ALA292, PRO312, LEU313, VAL313, PHE314, ARG315, TYR316, VAL319, and TRP343 with other forms of bonding

Characterization of antioxidant activity of Momordica charantia fruit by infrared-based fingerprinting

Momordica charantia is widely consumed edible fruit. The food and pharmaceutical industries use it as a natural antioxidant. However, the quality control of M. charantia-based medicinal products is questionable due to the complexity of metabolites in this fruit. Hence, this study has developed a statistical model in predicting the antioxidant value through the 2, 2-diphenyl-1 picrylhydrazyl radical scavenging activity and ferric reducing antioxidant power based on infrared spectroscopy with attenuated total reflectance. This technique was reliably used for quality control. Six ethanol extracts (0, 20, 40, 60, 80, and 100% in water) of this plant’s fruit were prepared. The radical scavenging and ferric reducing antioxidant power activities were measured and the chemical profiling of the extracts was fingerprinted by infrared spectroscopy between 4,000 and 600 cm−1 at a resolution of 4 cm−1. Statistical analysis was developed by correlating the bioactivity and infrared spectra of each extract using orthogonal partial least square discriminant analysis. The C–N, C˭O, C–O, C–H, and OH infrared signals were positively correlated with biological activity. The antioxidant activity of the fruit of M. charantia may be due to the presence of several antioxidants that work synergistically

Antidiabetic and antioxidants activities of Clinacanthus nutans (Burm F.) Lindau leaves extracts

Clinacanthus nutans (C. nutans) is a local plant belongs to the family Acanthaceae. It is consumed as ‘jamu’ (healthy drink) in Indonesia and as ‘ulam’ in Malaysia. This plant has been claimed for its ability to prevent many diseases including diabetes. However, its scientific proof on this claim is still lacking. Thus, this study was designed to evaluate the antidiabetic potential and antioxidant capacity of C. nutans leaves extracts using in vitro bioassay tests. The 80% methanolic crude extract of this plant was further partitioned using different polarity solvents viz., hexane, hexane: ethyl acetate (1:1, v/v), ethyl acetate, ethyl acetate: methanol (1:1, v/v) and methanol. All the sub-fractions were analysed for antioxidant effect via 2, 2-diphenyl-2-picrylhydrazil (DPPH) scavenging activity, ferric reducing power (FRAP) and xanthine oxidase (XO) assays followed by antidiabetic evaluation via α-glucosidase and dipeptidyl peptidase-IV (DPP-IV) inhibitory assays and glucose uptake experiment. The ethyl acetate fraction showed a good antioxidant potential while hexane exhibit high α-glucosidase and DPP-IV enzyme inhibition. The hexane fraction also improved glucose uptake in a dose-dependent manner. The study provides an informative data on the potential of C. nutans to be developed as a functional food in preventing diabetes

Evaluation of antidiabetic properties of Momordica charantia in streptozotocin induced diabetic rats using metabolomics approach

Momordica charantia, also known as bitter melon or 'peria katak' in Malaysia, is a member of the family Cucurbitaceae. Bitter melon is an excellent source of vitamins and minerals that made it extensively nutritious. Moreover, the seed, fruit and leave of the plant contain bioactive compounds with a wide range of biological activities that have been used in traditional medicines in the treatment of several diseases, including inflammation, infections, obesity and diabetes. The aim of this study was to evaluate changes in urinary metabolite profile of the normal, streptozotocin-induced type 1 diabetes and M. charantia treated diabetic rats using proton nuclear magnetic resonance (1H-NMR) -based metabolomics profiling. Study had been carried out by inducing diabetes in the rats through injection of streptozotocin, which exhibited type 1 diabetes. M. charantia extract (100 and 200 mg/kg body weight) was administrated to the streptozotocin-induced diabetic rats for one week. Blood glucose level after administration was measured to examine hypoglycemic effect of the extract. The results obtained indicated that M. charantia was effective in lowering blood glucose level of the diabetic rats. The loading plot of Partial Least Square (PLS) component 1 showed that diabetic rats had increased levels of lactate and glucose in urine whereas normal and the extract treated diabetic rats had higher levels of succinate, creatine, creatinine, urea and phenylacetylglycine in urine. While the loading plot of PLS component 2 showed a higher levels of succinate, citrate, creatine, creatinine, sugars, and hippurate in urine of normal rat compared to the extract treated diabetic rat. Administration of M. charantia extract was found to be able to regulate the altered metabolic processes. Thus, it could be potentially used to treat the diabetic patients

Antioxidant and antidiabetic effects of flavonoids: a structure-activity relationship based study

The best described pharmacological property of flavonoids is their capacity to act as potent antioxidant that has been reported to play an important role in the alleviation of diabetes mellitus. Flavonoids biochemical properties are structure dependent; however, they are yet to be thoroughly understood. Hence, the main aim of this work was to investigate the antioxidant and antidiabetic properties of some structurally related flavonoids to identify key positions responsible, their correlation, and the effect of methylation and acetylation on the same properties. Antioxidant potential was evaluated through dot blot, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ABTS+ radical scavenging, ferric reducing antioxidant power (FRAP), and xanthine oxidase inhibitory (XOI) assays. Antidiabetic effect was investigated through α-glucosidase and dipeptidyl peptidase-4 (DPP-4) assays. Results showed that the total number and the configuration of hydroxyl groups played an important role in regulating antioxidant and antidiabetic properties in scavenging DPPH radical, ABTS+ radical, and FRAP assays and improved both α-glucosidase and DPP-4 activities. Presence of C-2-C-3 double bond and C-4 ketonic group are two essential structural features in the bioactivity of flavonoids especially for antidiabetic property. Methylation and acetylation of hydroxyl groups were found to diminish the in vitro antioxidant and antidiabetic properties of the flavonoids

Toxicity and teratogenicity evaluation of ethanolic extract from Momordica charantia fruit using zebrafish (Danio rerio) embryo model

Zebra fish (Danio rerio), a freshwater fish, has become a favoured animal model to assess the teratogenicity effects of various compounds. Momordica charantia is a fruit traditionally used as a functional food to treat various ailments. In the present work, 80% ethanolic extract of M. charantia fruit was investigated for its teratogenicity effects on the zebrafish embryos. The embryos of 12 h post-fertilisation were immersed in the ethanolic extract at various concentrations of 250, 500, 750, 1,000, and 1,250 mg/L prepared in 2% DMSO. Microscopic observation was carried out every 24 h. Results showed an increased mortality rate, and a delayed hatching rate with increasing concentration. Some of the deformities observed included hyperactivity, crooked backbone, reduced pigmentation, awkward positioning, and coagulation at the highest concentration. Probit analysis resulted in 725.90 mg/L as the median lethal concentration (LC50). Chromatographic analysis revealed the presence of propanedioic acid, malic acid, contrunculin-A, glutamine, D-fructose, sorbopyranose, xylitol, galactonic acid, D-mannitol, and mannose. These compounds may contribute to the deformities observed in a concentration-dependent manner. Therefore, M. charantia fruit must be consumed with caution and within the recommended amount

Rapid investigation of α-glucosidase inhibitory activity of Clinacanthus nutans leaf using infrared fingerprinting

The analytical method used in the quality control of Clinacanthus nutans leaves has not been well developed. Therefore, this study aimed to develop a simple analytical method to predict α-glucosidase inhibitory activity of this herb based on its infrared fingerprinting. The dried extracts obtained from maceration using solvents with different polarities were evaluated for the α-glucosidase inhibitory activity and analysed through infrared spectroscopy. Multivariate data analysis was performed by correlating the bioactivity and infrared spectrum of each extract using partial least square method. The loading plot from multivariate data analysis revealed that C single bond H and Cdouble bond O infrared signals from terpenoids in the extract were positively correlated with the α-glucosidase inhibitory activity. The developed partial least square model was validated through a testing on the external samples. The result concludes that the developed model is valid and capable of predicting α-glucosidase inhibitory activity of the external samples

Antidiabetic and antioxidants activities of Clinacanthus nutans (Burm F.) Lindau leaves extracts

Clinacanthus nutans (Acanthaceae) is a local plant consumed as tisane in Indonesia and ‘ulam’ in Malaysia. This plant has been claimed for its ability to prevent many diseases including diabetes. However, the scientific proof on this claim is still lacking. Therefore, the present work study was designed to evaluate the antidiabetic potential and antioxidant capacity of C. nutans leaves extracts using in vitro bioassay tests. The 80% methanolic crude extract of this plant was further partitioned using different polarity solvents namely hexane, hexane:ethyl acetate (1:1, v/v), ethyl acetate, ethyl acetate:methanol (1:1, v/v), and methanol. All the sub-fractions were analysed for antioxidant effect via 2, 2-diphenyl-2-picrylhydrazil (DPPH) scavenging activity, ferric reducing power (FRAP) and xanthine oxidase (XO) assays followed by antidiabetic evaluation via α-glucosidase and dipeptidyl peptidase-IV (DPP-IV) inhibitory assays and glucose uptake experiment. The ethyl acetate fraction showed a good antioxidant potential while the hexane fraction exhibited high α-glucosidase and DPP-IV enzyme inhibition. The hexane fraction also improved glucose uptake in a dose-dependent manner. The present work thus provides an informative data on the potential of C. nutans to be developed as a functional food in preventing diabetes