Viduranga Y. Waisundara

Evaluation of the Total Antioxidant Capacity, Polyphenol Contents and Starch Hydrolase Inhibitory Activity of Ten Edible Plants in an In vitro Model of Digestion

The total phenolics contents, total antioxidant capacity (TAC) and starch hydrolase inhibitory activity of the aqueous extracts of 10 edible plants and the stability of these parameters after the gastric and duodenal digestion in an in vitro model was investigated. The TAC was evaluated using the oxygen radical absorbance capacity (ORAC) assay, ferric reducing antioxidant power (FRAP) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH•) and 2, 2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) radical scavenging assays. Characterization and quantification of five polyphenol compounds which were previously identified to be present in all the selected plants were carried out. None of the extracts showed a decrease in the total phenolics content or the ORAC and FRAP values following digestion. None of the quantified phenolic compounds had decreased during any of the digestion phases – an observation which was deemed as beneficial in terms of therapeutic properties. Overall, the parameters analyzed were relatively stable throughout the digestive process in all the extracts.

Health, Wellness, and Safety Aspects of the Consumption of Kombucha

Functional foods have been identified as whole foods and fortified, enriched, or enhanced products which have a potentially beneficial effect on health when consumed as part of a varied diet on a regular basis, at effective levels. As consumer awareness on functional food escalates, the interest towards conducting scientific studies in this field has also proportionately increased. Many of the traditional food products are known to possess bioactive components, thus qualifying as functional food. Kombucha tea is produced by fermenting sugared black tea with a mixed culture of yeast and bacteria. Kombucha tea has gained immense popularity in recent times due to many associated health benefits. The therapeutic effects of this beverage are thought to be derived from the chemical composition of this beverage, mainly the polyphenols and secondary metabolites which are produced during fermentation. However, the safety aspects of the beverage also need to be taken into account when qualifying the beverage as a functional food. Nevertheless, Kombucha tea could be easily recognized as a beverage which is able to replace the consumption of carbonated beverages due to its possession of health benefits and therapeutic properties.

Antidiabetic Properties, Bioactive Constituents, and Other Therapeutic Effects of Scoparia dulcis.

This review discusses the antidiabetic activities of Scoparia dulcis as well as its antioxidant and anti-inflammatory properties in relation to the diabetes and its complications. Ethnomedical applications of the herb have been identified as treatment for jaundice, stomach problems, skin disease, fever, and kidney stones, reproductory issues, and piles. Evidence has been demonstrated through scientific studies as to the antidiabetic effects of crude extracts of S. dulcis as well as its bioactive constituents. The primary mechanisms of action of antidiabetic activity of the plant and its bioactive constituents are through α-glucosidase inhibition, curbing of PPAR-γ and increased secretion of insulin. Scoparic acid A, scoparic acid D, scutellarein, apigenin, luteolin, coixol, and glutinol are some of the compounds which have been identified as responsible for these mechanisms of action. S. dulcis has also been shown to exhibit analgesic, antimalarial, hepatoprotective, sedative, hypnotic, antiulcer, antisickling, and antimicrobial activities. Given this evidence, it may be concluded that S. dulcis could be promoted among the masses as an alternative and complementary therapy for diabetes, provided further scientific studies on the toxicological and pharmacological aspects are carried out through either in vivo or clinical means.

Free radical scavenging ability of Aspalathus linearis in two in vitro models of diabetes and cancer

The free radical scavenging activity of Aspalathus linearis (Rooibos tea) and its effect on reactive oxygen species (ROS), catalase (CAT), and superoxide dismutase (SOD) were investigated in two in vitro disease models of cancer and diabetes. Although the antioxidant activity of this tea has been reported in several studies, its effects in disease models of ROS-induced oxidative stress have not been systematically evaluated to date. The oxygen radical absorbance capacity (ORAC) assay was used in this study to quantify the antioxidant capacity of the extract, whereas the ROS scavenging ability in hyperglycemia-induced human umbilical vein endothelial cells (HUVECs) and HeLa cells were investigated. The CAT and SOD assays were also carried out in the two disease models in order to evaluate the effect of the extract in the stimulation of these two enzyme activities. The extract was observed to have reduced ROS in a dose-dependent manner in both HUVECs and HeLa cells. The stimulation of the CAT and SOD enzyme activities were observed to be dose-dependent as well. The high ORAC value of the extract indicated the presence of antioxidant compounds which could directly quench ROS, whereby this mechanism of action could be hypothesized to have been further complemented through the stimulation of CAT and SOD. Overall, the Aspalathus linearis extract was observed to have increased the CAT and SOD activities in two in vitro disease models of cancer and hyperglycemia. Given the correlation between the ORAC values, the increases in CAT and SOD activities and the reduction in ROS in a dose-dependent manner, it could be hypothesized that the extract had a significant therapeutic potential for either the prevention of the onset of the two diseases or their progression because ROS has been identified as their root causes.

Determination of the Total Antioxidant Capacity and Quantification of Phenolic Compounds of Different Solvent Extracts of Black Mustard Seeds (Brassica nigra)

The total antioxidant capacity of Brassica nigra seeds (black mustard seeds) and the presence of phenolic compounds which are known to exist in seeds of this family were quantified. Oxygen radical absorbance capacity assay, ferric reducing antioxidant power, and the 2, 2-diphenyl-1-picrylhydrazyl and 2, 2-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging assays were conducted on dichloromethane, ethanol, ethyl acetate, hexane, methanol, and water extracts of the seeds. Water and ethanol extracts displayed the highest antioxidant activity. Phenolic compounds which have been known to demonstrate antioxidant properties such as catechin, epicatechin, gallic acid, myricetin, quercetin, and rutin were present in all extracts.

An appraisal of eighteen commonly consumed edible plants as functional food based on their antioxidant and starch hydrolase inhibitory activities

BACKGROUND Eighteen edible plants were assessed for their antioxidant potential based on oxygen radical absorbance capacity (ORAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, total phenolics, vitamin C content and various lipophilic antioxidants. The inhibitory activities of the plant extracts against the enzymatic activities of α-amylase and α-glucosidase were also evaluated. RESULTS The antioxidant and starch hydrolase activities of the plants varied widely across a single batch of analysis. The ORAC and DPPH radical scavenging EC50 values varied between 298 and 1984 Trolox equivalents g(-1) fresh weight and between 91 and 533 mg kg(-1) fresh weight, respectively. The total phenolics and vitamin C contents varied between 32 and 125 mg gallic acid equivalents g(-1) fresh weight and between 96 and 285 µg g(-1) fresh weight, respectively. All the plants contained neoxanthin, violaxanthin, and α- and β-carotene in varying amounts. Coccinia grandis, Asparagus racemosus, Costus speciosus, Amaranthus viridis and Annona muricata displayed the highest inhibitory activities against starch hydrolases. They were the most efficient against the breakdown of seven starches exposed to the two enzymes as well. CONCLUSIONS Overall, the edible plants were observed to display a high antioxidant potential with starch hydrolase inhibitory properties, which were beneficial in their being recognized as functional food.

Review: Mimosa pudica Linn.: the garden weed with therapeutic properties

Mimosa pudica is a commonly found weed which is easily dismissed as an invasive plant. Despite its inferior status, M. pudica has a significant history in several traditional medicinal systems as a potent therapeutic agent possessing antioxidant, anti-inflammatory and antimicrobial properties. In terms of diseases, it has been traditionally used for the prevention and control of diabetes and cancer as well as their prevailing complications. Several terpenoids, flavonoids, glycosides, alkaloids, quinines, phenols, tannins, saponins, and coumarins have been identified in all plants of the plant. In particular, mimosine – an amine containing anti-cancer properties –has been identified in abundance in the plant extracts. Given the need for plants as well as their bioactive compounds of ethno-botanical significance displaying a complete range of biological activities, M. pudica can be easily highlighted as a plant material of interest which warrants further clinical investigation.

The Antioxidant and Starch Hydrolase Inhibitory Activity of Ten Spices in an In Vitro Model of Digestion: Bioaccessibility of Anthocyanins and Carotenoids

The antioxidant and starch hydrolase inhibitory activities of cardamom, cloves, coriander, cumin seeds, curry leaves, fenugreek, mustard seeds, nutmeg, sweet cumin, and star anise extracts were investigated in an in vitro model of digestion mimicking the gastric and duodenal conditions. The total phenolic contents in all spice extracts had statistically significantly (P < 0.05) increased following both gastric and duodenal digestion. This was also in correlation with the antioxidant assays quantifying the water-soluble antioxidant capacity of the extracts. The lipophilic Oxygen Radical Absorbance Capacity assay did not indicate a statistically significant change in the values during any of the digestion phases. Statistically significant (P < 0.05) reductions in the anthocyanin contents were observed during the digestion phases in contrast to the carotenoid contents. With the exception of the cumin seed extract, none of the spice extracts showed statistically significant changes in the initial starch hydrolase enzyme inhibitory values prior to gastric and duodenal digestion. In conclusion, this study was able to prove that the 10 spices were a significant source of total phenolics, antioxidant, and starch hydrolase inhibitory activities.

The classification of sri lankan medicinal herbs: an extensive comparison of the antioxidant activities.

Sri Lanka has variety of herbs whose effectiveness has been proven across many generations. These herbs are classified into two groups - ′heating′ and ′cooling′, based on the physiological reactions upon consumption. Application-wise, the ′cooling′ herbs are administered to patients contracted with diabetes, imbalances in the lipid profile, or even cancer. However, this classification has been misunderstood due to inconsistent interpretations and lack of scientific reasoning. This study systematically determines the rationale behind this classification, by specifically evaluating the antioxidant activity of 18 herbs - nine herbs from each category. The oxygen radical absorbance capacities, DPPH radical scavenging activities, and the total phenolic contents are analyzed here. The ′heating′ herbs have a comparatively lower antioxidant potential than the ′cooling′ herbs. The total phenolic contents correlate with the antioxidant values. It can be hypothesized that the high antioxidant potential of the ′cooling′ herbs may have been responsible for the containment of the diseases mentioned previously.

Bittergourd (Momordica charantia) scavenges free radicals by enhancing the expression of superoxide dismutase in in vitro models of diabetes and cancer

The free radical scavenging activity of the bittergourd extract (Momordica charantia) and its effect on reactive oxygen species (ROS) and superoxide dismutase (SOD) was investigated. Although its anti-hyperglycemic effects have been thoroughly studied, its effects against hyperglycemia-induced oxidative stress have not been systematically assessed. The oxygen radical absorbance capacity (ORAC) assay quantified the antioxidant capacity of the extract, while the ROS scavenging ability in hyperglycemia-induced human umbilical vein endothelial cells and HeLa cells was investigated. The SOD assay was also carried out. The extract was observed to have reduced ROS in a dose-dependent manner. The stimulation of SOD activity was also dose dependent. The low ORAC value of the extract indicated the absence of antioxidant compounds, which could directly quench ROS. Instead, the extract had stimulated the SOD expression, thereby quenching the ROS. The extract was observed to be beneficial for diseases that are associated with free radical-induced oxidative damage.